Geomorphic Proxies to Test Strain Accommodation in Southwestern Puerto Rico from Digital Elevation Models

NASA Astrophysics Data System (ADS)

Barrios Galindez, I. M.; Xue, L.; Laó-Dávila, D. A.

2017-12-01

The Puerto Rico and the Virgin Island microplate is located in at the northeastern corner of the Caribbean plate boundary with North America is placed within an oblique subduction zone in which strain patterns remain unresolved. Seismic hazard is a major concern in the region as seen from the seismic history of the Caribbean-North America plate boundary zone. Most of the tectonic models of the microplate show the accommodation of strain occurring offshore, despite evidence from seismic activity, trench studies, and geodetic studies suggesting the existence of strain accomodation in southwest Puerto Rico. These studies also suggest active faulting specially in the western part of the island, but limited work has been done regarding their mechanism. Therefore, this work aims to define and map these active faults in western Puerto Rico by integrating data from analysis of fluvial terrains, and detailed mapping using digital elevation model (DEM) extracted from Shuttle Radar Topography Mission (SRTM) and LIDAR data. The goal is to (1) identify structural features such as surface lineaments and fault scarps for the Cerro Goden fault, South Lajas fault, and other active faults in the western of Puerto Rico, (2) correlate these information with the distribution pattern and values of the geomorphic proxies, including Chi integral (χ), normalized steepness (ksn) and Asymmetric factor (AF). Our preliminary results from geomorphic proxies and Lidar data provide some insight of the displacement and stage of activities of these faults (e.g. Boqueron-Punta Malva Fault and Cerro Goden fault). Also, the anomaly of the geomorphic proxies generally correlate with the locations of the landslides in the southwestern Puerto Rico. The geomorphic model of this work include new information of active faulting fundamental to produce better seismic hazards maps. Additionally, active tectonics studies are vital to issue and adjust construction buildings codes and zonification codes.

Airborne laser swath mapping of the Denton Hills, Transantarctic Mountains, Antarctica: Applications for structural and glacial geomorphic mapping

USGS Publications Warehouse

Wilson, Terry; Csathó, Beata

2007-01-01

High-resolution digital elevation data acquired by airborne laser scanning (ALS) for the Denton Hills, along the coastal foothills of the Royal Society Range, Transantarctic Mountains, are examined for applications to bedrock and glacial geomorphic mapping. Digital elevation models (DEMs), displayed as shaded-relief images and slope maps, portray geomorphic landscape features in unprecedented detail across the region. Structures of both ductile and brittle origin, ranging in age from the Paleozoic to the Quaternary, can be mapped from the DEMs. Glacial features, providing a record of the limits of grounded ice, of lake paleoshorelines, and of proglacial lake-ice conveyor deposits, are also prominent on the DEMs. The ALS-derived topographic data have great potential for a range of mapping applications in regions of ice-free terrain in Antarctica

White Sands Missile Range Main Cantonment and NASA Area Faults, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nash, Greg

This is a zipped ArcGIS shapefile containing faults mapped for the Tularosa Basin geothermal play fairway analysis project. The faults were interpolated from gravity and seismic (NASA area) data, and from geomorphic features on aerial photography. Field work was also done for validation of faults which had surface expressions.

Geomorphic evidence of deformation in the northern part of the New Madrid seismic zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, K.J.; Schumm, S.A.

1993-03-01

A geomorphic evaluation of the northern portion of the New Madrid seismic zone between Hickman, KY and Osceola, AR has identified several locations where anomalous geomorphic conditions indicate possible surface deformation. For example, the slope, course, sinuosity and dimensions of the Mississippi River have been affected by the Lake County uplift and Tertiary-age sediments are exposed in its channel. Also, anomalous channel behavior near Caruthersville, MO and Barfield, AR suggests that these two reaches of the Mississippi River are structurally controlled. The Black River northeast of Pocahontas follows a peculiar angular course that suggests fracture control, and course changes ofmore » the Black, St. Francis, and Little Rivers may be related to subsurface faulting, uplift, or downwarping, as well as to differential compaction or the effects of groundwater withdrawal. The topography of Crowley's Ridge suggests that, between Jonesboro and Castor River, it is composed of at least three structural blocks, that are bounded by northeast-southwest trending faults. Near Jonesboro, river patterns appear to be affected by the Jonesboro, AR pluton. The geomorphic evaluation has identified anomalous surface features in the New Madrid seismic zone. Some can be directly linked to mapped structures in the region, whereas others may result from previously unidentified areas of surface deformation. The identification of these anomalies should provide direction for scientists who are employing subsurface techniques in order to locate tectonic deformation in the area.« less

Recently active contractile deformation in the forearc of southern Peru

NASA Astrophysics Data System (ADS)

Hall, S. R.; Farber, D.; Audin, L.; Finkel, R. C.

2010-12-01

In the Precordillera and Western Cordillera of southern Peru (14°-18°S), vast pediment surfaces have been abandoned through drainage diversion and river incision, with the major drainages carving deep canyons. Within this region, we have identified range-sub-parallel contractile structures that accommodate significant distributed crustal deformation. Young geomorphic features document both the presence and youthfulness of these contractile structures. Here, we determine exposure ages on geomorphic features such as pediment surfaces and fluvial terraces using in situ produced cosmogenic radionuclides, in conjunction with field and remote mapping. This chronologic data reveals that ancient surfaces have been preserved as a result of very low erosion rates. We measure this rate to be <0.5m/Ma on genetically similar surfaces spanning over 4 degrees of latitude throughout this region. While many ancient surfaces are preserved in forearc localities, we also observe young (30ka-1Ma) low-relief pediment surfaces modified by recent processes. Specifically, active structures accommodating compressional stresses locally displace active drainages and offset river terraces leading to their abandonment. Based on our chronology and geomorphic mapping, we calculate a Pleistocene river incision rate of ~0.3mm/yr determined from data collected along exoreic rivers. This rate is consistent with longer-term incision rates measured in other localities along this margin. We suggest that, in this region of southern Peru, the steep western wedge of the Andean margin supports the high topography of the Altiplano through a combination of uplift along steeply dipping contractile west-vergent structures and isostatic responses to the focused removal of large amounts of crustal material through canyon incision. Further, that these range sub-parallel structures are related at depth to a thrust system that plays a role in not only the maintenance of the Andean margin, but potentially in its formation as well.

High-resolution topography along surface rupture of the 16 October 1999 Hector Mine, California (Mw 7.1) from airborne laser swath mapping

USGS Publications Warehouse

Hudnutt, K.W.; Borsa, A.; Glennie, C.; Minster, J.-B.

2002-01-01

In order to document surface rupture associated with the Hector Mine earthquake, in particular, the area of maximum slip and the deformed surface of Lavic Lake playa, we acquired high-resolution data using relatively new topographic-mapping methods. We performed a raster-laser scan of the main surface breaks along the entire rupture zone, as well as along an unruptured portion of the Bullion fault. The image of the ground surface produced by this method is highly detailed, comparable to that obtained when geologists make particularly detailed site maps for geomorphic or paleoseismic studies. In this case, however, for the first time after a surface-rupturing earthquake, the detailed mapping is along the entire fault zone rather than being confined to selected sites. These data are geodetically referenced, using the Global Positioning System, thus enabling more accurate mapping of the rupture traces. In addition, digital photographs taken along the same flight lines can be overlaid onto the precise topographic data, improving terrain visualization. We demonstrate the potential of these techniques for measuring fault-slip vectors.

Neotectonics and geomorphic evolution of the northwestern arm of the Yellowstone Tectonic Parabola: Controls on intra-cratonic extensional regimes, southwest Montana

USGS Publications Warehouse

Ruleman, Chester A.; Larsen, Mort; Stickney, Michael C.

2014-01-01

The catastrophic Hebgen Lake earthquake of 18 August 1959 (MW 7.3) led many geoscientists to develop new methods to better understand active tectonics in extensional tectonic regimes that address seismic hazards. The Madison Range fault system and adjacent Hebgen Lake–Red Canyon fault system provide an intermountain active tectonic analog for regional analyses of extensional crustal deformation. The Madison Range fault system comprises fault zones (~100 km in length) that have multiple salients and embayments marked by preexisting structures exposed in the footwall. Quaternary tectonic activity rates differ along the length of the fault system, with less displacement to the north. Within the Hebgen Lake basin, the 1959 earthquake is the latest slip event in the Hebgen Lake–Red Canyon fault system and southern Madison Range fault system. Geomorphic and paleoseismic investigations indicate previous faulting events on both fault systems. Surficial geologic mapping and historic seismicity support a coseismic structural linkage between the Madison Range and Hebgen Lake–Red Canyon fault systems. On this trip, we will look at Quaternary surface ruptures that characterize prehistoric earthquake magnitudes. The one-day field trip begins and ends in Bozeman, and includes an overview of the active tectonics within the Madison Valley and Hebgen Lake basin, southwestern Montana. We will also review geologic evidence, which includes new geologic maps and geomorphic analyses that demonstrate preexisting structural controls on surface rupture patterns along the Madison Range and Hebgen Lake–Red Canyon fault systems.

New geomorphic data on the active Taiwan orogen: A multisource approach

NASA Technical Reports Server (NTRS)

Deffontaines, B.; Lee, J.-C.; Angelier, J.; Carvalho, J.; Rudant, J.-P.

1994-01-01

A multisource and multiscale approach of Taiwan morphotectonics combines different complementary geomorphic analyses based on a new elevation model (DEM), side-looking airborne radar (SLAR), and satellite (SPOT) imagery, aerial photographs, and control from independent field data. This analysis enables us not only to present an integrated geomorphic description of the Taiwan orogen but also to highlight some new geodynamic aspects. Well-known, major geological structures such as the Longitudinal Valley, Lishan, Pingtung, and the Foothills fault zones are of course clearly recognized, but numerous, previously unrecognized structures appear distributed within different regions of Taiwan. For instance, transfer fault zones within the Western Foothills and the Central Range are identified based on analyses of lineaments and general morphology. In many cases, the existence of geomorphic features identified in general images is supported by the results of geological field analyses carried out independently. In turn, the field analyses of structures and mechanisms at some sites provide a key for interpreting similar geomorphic featues in other areas. Examples are the conjugate pattern of strike-slip faults within the Central Range and the oblique fold-and-thrust pattern of the Coastal Range. Furthermore, neotectonic and morphological analyses (drainage and erosional surfaces) has been combined in order to obtain a more comprehensive description and interpretation of neotectonic features in Taiwan, such as for the Longitudinal Valley Fault. Next, at a more general scale, numerical processing of digital elevation models, resulting in average topography, summit level or base level maps, allows identification of major features related to the dynamics of uplift and erosion and estimates of erosion balance. Finally, a preliminary morphotectonic sketch map of Taiwan, combining information from all the sources listed above, is presented.

An evaluation of the effectiveness of low-cost UAVs and structure from motion for geomorphic change detection

NASA Astrophysics Data System (ADS)

Cook, Kristen L.

2017-02-01

The measurement of topography and of topographic change is essential for the study of many geomorphic processes. In recent years, structure from motion (SfM) techniques applied to photographs taken by camera-equipped unmanned aerial vehicles (UAVs) has become a powerful new tool for the generation of high resolution topography. The variety of available UAV systems continues to increase rapidly, but it is not clear whether increased UAV sophistication translates into improved quality of the calculated topography. To evaluate the lower end of the UAV spectrum, a simple low cost UAV was deployed to calculate high resolution topography in the Daan River gorge in western Taiwan, a site with a complicated 3D morphology and a wide range of surface types, making it a challenging site for topographic measurement. Terrestrial lidar surveys were conducted in parallel with UAV surveys in both June and November 2014, enabling an assessment of the reliability of the UAV survey to detect geomorphic changes in the range of 30 cm to several meters. A further UAV survey was conducted in June 2015 in order to quantify changes resulting from the 2015 spring monsoon. To evaluate the accuracy of the UAV derived topography, it was compared to terrestrial lidar data collected during the same survey period using the cloud-to-cloud comparison algorithm M3C2. The UAV-generated point clouds match the lidar point clouds well, with RMS errors of 30-40 cm; however, the accuracy of the SfM point clouds depends strongly on the characteristics of the surface being considered, with vegetation, water, and small scale texture causing inaccuracies. The lidar and SfM data yield similar maps of change from June to November 2014, with the same areas of geomorphic change detected by both methods. The SfM-generated change map for November 2014 to June 2015 indicates that the 2015 spring monsoon caused erosion throughout the gorge and highlights the importance of event-driven erosion in the Daan River. The results suggest that even very basic UAVs can yield data suitable for measuring geomorphic change on the scale of a channel reach.

Advances in Planetary Geology

NASA Technical Reports Server (NTRS)

Grant, John A., III; Nedell, Susan S.

1987-01-01

The surface of Mars displays a broad range of channel and valley features. There is as great a range in morphology as in scale. Some of the features of Martian geography are examined. Geomorphic mapping, crater counts on selected surfaces, and a detailed study of drainage basins are used to trace the geologic evolution of the Margaritifer Sinus Quandrangle. The layered deposits in the Valles Marineris are described in detail and the geologic processes that could have led to their formation are analyzed.

Part 1: The geomorphic evolution of Eastern Margaritifer Sinus, Mars

NASA Technical Reports Server (NTRS)

Grant, John A., III

1987-01-01

Geomorphic mapping, crater counts on selected surfaces, and a detailed study of drainage basins, were used to trace the geologic evolution of Margaritifer Sinus Quandrangle. The oldest dated surface covering these basins evolved during the period of intense bombardment. Since that time four resurfacing events have occurred. The first three were all of regional extent, while the fourth, occurred locally, filling basins. Valley networks, incised in the third event unit, are always buried by the fourth event unit when present. A peak in geomorphic activity occurred from 10,000 to 5000. Events during this period included the formation of Uzboi/Ladon Valles with deposition in Ladon Basin, and the formation of Samara and Parana/Loire Valles in MC19SE. Flow out of Ladon Basin and to a lesser extent Samara and Parana/Loire Valles created etched terrain at their confluence that was synchronous with initiation of Margaritifer and Iani Chaos. The range of dates for the chaos may be due to periodic collapse. The extensive, well integrted nature of Samara and Parana/Loire Valles requires the existence of a long period of favorable climatic conditions to allow their formation. Development of these two systems was probably through sapping processes.

Exploring discrepancies between quantitative validation results and the geomorphic plausibility of statistical landslide susceptibility maps

NASA Astrophysics Data System (ADS)

Steger, Stefan; Brenning, Alexander; Bell, Rainer; Petschko, Helene; Glade, Thomas

2016-06-01

Empirical models are frequently applied to produce landslide susceptibility maps for large areas. Subsequent quantitative validation results are routinely used as the primary criteria to infer the validity and applicability of the final maps or to select one of several models. This study hypothesizes that such direct deductions can be misleading. The main objective was to explore discrepancies between the predictive performance of a landslide susceptibility model and the geomorphic plausibility of subsequent landslide susceptibility maps while a particular emphasis was placed on the influence of incomplete landslide inventories on modelling and validation results. The study was conducted within the Flysch Zone of Lower Austria (1,354 km2) which is known to be highly susceptible to landslides of the slide-type movement. Sixteen susceptibility models were generated by applying two statistical classifiers (logistic regression and generalized additive model) and two machine learning techniques (random forest and support vector machine) separately for two landslide inventories of differing completeness and two predictor sets. The results were validated quantitatively by estimating the area under the receiver operating characteristic curve (AUROC) with single holdout and spatial cross-validation technique. The heuristic evaluation of the geomorphic plausibility of the final results was supported by findings of an exploratory data analysis, an estimation of odds ratios and an evaluation of the spatial structure of the final maps. The results showed that maps generated by different inventories, classifiers and predictors appeared differently while holdout validation revealed similar high predictive performances. Spatial cross-validation proved useful to expose spatially varying inconsistencies of the modelling results while additionally providing evidence for slightly overfitted machine learning-based models. However, the highest predictive performances were obtained for maps that explicitly expressed geomorphically implausible relationships indicating that the predictive performance of a model might be misleading in the case a predictor systematically relates to a spatially consistent bias of the inventory. Furthermore, we observed that random forest-based maps displayed spatial artifacts. The most plausible susceptibility map of the study area showed smooth prediction surfaces while the underlying model revealed a high predictive capability and was generated with an accurate landslide inventory and predictors that did not directly describe a bias. However, none of the presented models was found to be completely unbiased. This study showed that high predictive performances cannot be equated with a high plausibility and applicability of subsequent landslide susceptibility maps. We suggest that greater emphasis should be placed on identifying confounding factors and biases in landslide inventories. A joint discussion between modelers and decision makers of the spatial pattern of the final susceptibility maps in the field might increase their acceptance and applicability.

Multiple resource evaluation of region 2 US forest service lands utilizing LANDSAT MSS data. [San Juan Mountains, Colorado

NASA Technical Reports Server (NTRS)

Krebs, P. V.; Hoffer, R. M. (Principal Investigator)

1976-01-01

The author has identified the following significant results. LANDSAT MSS imagery provided an excellent overview which put a geomorphic study into a regional perspective, using scale 1:250,000 or smaller. It was used for deriving a data base for land use planning for southern San Juan Mountains. Stereo pairing of adjacent images was the best method for all geomorphic mapping. Combining this with snow enhancement, seasonal enhancement, and reversal aided in interpretation of geomorphic features. Drainage patterns were mapped in much greater detail from LANDSAT than from a two deg quadrangle base.

Changes in Landscape-level Carbon Balance of an Arctic Coastal Plain Tundra Ecosystem Between 1970-2100, in Response to Projected Climate Change

NASA Astrophysics Data System (ADS)

Lara, M. J.; McGuire, A. D.; Euskirchen, E. S.; Genet, H.; Sloan, V. L.; Iversen, C. M.; Norby, R. J.; Zhang, Y.; Yuan, F.

2014-12-01

Northern permafrost regions are estimated to cover 16% of the global soil area and account for approximately 50% of the global belowground organic carbon pool. However, there are considerable uncertainties regarding the fate of this soil carbon pool with projected climate warming over the next century. In northern Alaska, nearly 65% of the terrestrial surface is composed of polygonal tundra, where geomorphic land cover types such as high-, flat-, and low-center polygons influence local surface hydrology, plant community composition, nutrient and biogeochemical cycling, over small spatial scales. Due to the lack of representation of these fine-scale geomorphic types and ecosystem processes, in large-scale terrestrial ecosystem models, future uncertainties are large for this tundra region. In this study, we use a new version of the terrestrial ecosystem model (TEM), that couples a dynamic vegetation model (in which plant functional types compete for water, nitrogen, and light) with a dynamic soil organic model (in which temperature, moisture, and associated organic/inorganic carbon and nitrogen pools/fluxes vary together in vertically resolved layers) to simulate ecosystem carbon balance. We parameterized and calibrated this model using data specific to the local climate, vegetation, and soil associated with tundra geomorphic types. We extrapolate model results at a 1km2 resolution across the ~1800 km2 Barrow Peninsula using a tundra geomorphology map, describing ten dominant geomorphic tundra types (Lara et al. submitted), to estimate the likely change in landscape-level carbon balance between 1970 and 2100 in response to projected climate change. Preliminary model runs for this region indicated temporal variability in carbon and active layer dynamics, specific to tundra geomorphic type over time. Overall, results suggest that it is important to consider small-scale discrete polygonal tundra geomorphic types that control local structure and function in regional estimates of carbon balance in northern Alaska.

Identification of Geomorphic Conditions Favoring Preservation of Multiple Individual Displacements Across Transform Faults

NASA Astrophysics Data System (ADS)

Williams, P. L.; Phillips, D. A.; Bowles-Martinez, E.; Masana, E.; Stepancikova, P.

2010-12-01

Terrestrial and airborne LiDAR data, and low altitude aerial photography have been utilized in conjunction with field work to identify and map single and multiple-event stream-offsets along all strands of the San Andreas fault in the Coachella Valley. Goals of the work are characterizing the range of displacements associated with the fault’s prehistoric surface ruptures, evaluating patterns of along-fault displacement, and disclosing processes associated with the prominent Banning-Mission Creek fault junction. Preservation offsets is associated with landscape conditions including: (1) well-confined and widely spaced source streams up-slope of the fault; (2) persistent geomorphic surfaces below the fault; (3) slope directions oriented approximately perpendicular to the fault. Notably, a pair of multiple-event offset sites have been recognized in coarse fan deposits below the Mission Creek fault near 1000 Palms oasis. Each of these sites is associated with a single source drainage oriented approximately perpendicular to the fault, and preserves a record of individual fault displacements affecting the southern portion of the Mission Creek branch of the San Andreas fault. The two sites individually record long (>10 event) slip-per-event histories. Documentation of the sites indicates a prevalence of moderate displacements and a small number of large offsets. This is consistent with evidence developed in systematic mapping of individual and multiple event stream offsets in the area extending 70 km south to Durmid Hill. Challenges to site interpretation include the presence of closely spaced en echelon fault branches and indications of stream avulsion in the area of the modern fault crossing. Conversely, strong bar and swale topography produce high quality offset indicators that can be identified across en echelon branches in most cases. To accomplish the detailed mapping needed to fully recover the complex yet well-preserved geomorphic features under investigation, a program of terrestrial laser scanning (TLS) was conducted at the 1000 Palms oasis stream offset sites. Data products and map interpretations will be presented along with initial applications of the study to characterizing San Andreas fault rupture hazard. Continuing work will seek to more fully populate the dataset of larger offsets, evaluate means to objectively date the larger offsets, and, as completely as possible, to characterize magnitudes of past surface ruptures of the San Andreas fault in the Coachella Valley.

Eastern Denali Fault surface trace map, eastern Alaska and Yukon, Canada

USGS Publications Warehouse

Bender, Adrian M.; Haeussler, Peter J.

2017-05-04

We map the 385-kilometer (km) long surface trace of the right-lateral, strike-slip Denali Fault between the Totschunda-Denali Fault intersection in Alaska, United States and the village of Haines Junction, Yukon, Canada. In Alaska, digital elevation models based on light detection and ranging and interferometric synthetic aperture radar data enabled our fault mapping at scales of 1:2,000 and 1:10,000, respectively. Lacking such resources in Yukon, we developed new structure-from-motion digital photogrammetry products from legacy aerial photos to map the fault surface trace at a scale of 1:10,000 east of the international border. The section of the fault that we map, referred to as the Eastern Denali Fault, did not rupture during the 2002 Denali Fault earthquake (moment magnitude 7.9). Seismologic, geodetic, and geomorphic evidence, along with a paleoseismic record of past ground-rupturing earthquakes, demonstrate Holocene and contemporary activity on the fault, however. This map of the Eastern Denali Fault surface trace complements other data sets by providing an openly accessible digital interpretation of the location, length, and continuity of the fault’s surface trace based on the accompanying digital topography dataset. Additionally, the digitized fault trace may provide geometric constraints useful for modeling earthquake scenarios and related seismic hazard.

Preliminary atlas of active shallow tectonic deformation in the Puget Lowland, Washington

USGS Publications Warehouse

Barnett, Elizabeth A.; Haugerud, Ralph A.; Sherrod, Brian L.; Weaver, Craig S.; Pratt, Thomas L.; Blakely, Richard J.

2010-01-01

This atlas presents an up-to-date map compilation of the geological and geophysical observations that underpin interpretations of active, surface-deforming faults in the Puget Lowland, Washington. Shallow lowland faults are mapped where observations of deformation from paleoseismic, seismic-reflection, and potential-field investigations converge. Together, results from these studies strengthen the identification and characterization of regional faults and show that as many as a dozen shallow faults have been active during the Holocene. The suite of maps presented in our atlas identifies sites that have evidence of deformation attributed to these shallow faults. For example, the paleoseismic-investigations map shows where coseismic surface rupture and deformation produced geomorphic scarps and deformed shorelines. Other maps compile results of seismic-reflection and potential-field studies that demonstrate evidence of deformation along suspected fault structures in the subsurface. Summary maps show the fault traces derived from, and draped over, the datasets presented in the preceding maps. Overall, the atlas provides map users with a visual overview of the observations and interpretations that support the existence of active, shallow faults beneath the densely populated Puget Lowland.

Geomorphic and geologic controls of geohazards induced by Nepal’s 2015 Gorkha earthquake

USGS Publications Warehouse

Kargel, J.S.; Leonard, G.J.; Shugar, D. H.; Haritashya, U. K.; Bevington, A.; Fielding, E.J.; Fujita, K.; Geertsema, M.; Miles, E. S.; Steiner, J.; Anderson, E.; Bajracharya, S.; Bawden, G.W.; Breashears, D. F.; Byers, A.; Collins, B.; Dhital, M. R.; Donnellan, A.; Evans, T. L.; Geai, M. L.; Glasscoe, M. T.; Green, D.; Gurung, D. R.; Heijenk, R.; Hilborn, A.; Hudnut, K.; Huyck, C.; Immerzeel, W. W.; Liming, Jiang; Jibson, R.; Kaab, A.; Khanal, N. R.; Kirschbaum, D.; Kraaijenbrink, P. D. A.; Lamsal, D.; Shiyin, Liu; Mingyang, Lv; McKinney, D.; Nahirnick, N. K.; Zhuotong, Nan; Ojha, S.; Olsenholler, J.; Painter, T.H.; Pleasants, M.; Pratima, K. C.; Yuan, Q. I.; Raup, B.H.; Regmi, D.; Rounce, D. R.; Sakai, A.; Donghui, Shangguan; Shea, J. M.; Shrestha, A. B.; Shukla, A.; Stumm, D.; van der Kooij, M.; Voss, K.; Xin, Wang; Weihs, B.; Lizong, Wu; Xiaojun, Yao; Yoder, M. R.; Young, N.

2016-01-01

The Gorkha earthquake (magnitude 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9000 people and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes’ induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision-makers. We mapped 4312 coseismic and postseismic landslides. We also surveyed 491 glacier lakes for earthquake damage but found only nine landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions.

Evaluation of LiDAR Imagery as a Tool for Mapping the Northern San Andreas Fault in Heavily Forested Areas of Mendocino and Sonoma Counties, California

NASA Astrophysics Data System (ADS)

Prentice, C. S.; Koehler, R. D.; Baldwin, J. N.; Harding, D. J.

2004-12-01

We are mapping in detail active traces of the San Andreas Fault in Mendocino and Sonoma Counties in northern California, using recently acquired airborne LiDAR (also known as ALSM) data. The LiDAR data set provides a powerful new tool for mapping geomorphic features related to the San Andreas Fault because it can be used to produce high-resolution images of the ground surfaces beneath the forest canopy along the 70-km-long section of the fault zone encompassed by the data. Our effort represents the first use of LiDAR data to map active fault traces in a densely vegetated region along the San Andreas Fault. We are using shaded relief images generated from bare-earth DEMs to conduct detailed mapping of fault-related geomorphic features (e.g. scarps, offset streams, linear valleys, shutter ridges, and sag ponds) between Fort Ross and Point Arena. Initially, we map fault traces digitally, on-screen, based only on the geomorphology interpreted from LiDAR images. We then conduct field reconnaissance using the initial computer-based maps in order to verify and further refine our mapping. We found that field reconnaissance is of utmost importance in producing an accurate and detailed map of fault traces. Many lineaments identified as faults from the on-screen images were determined in the field to be old logging roads or other features unrelated to faulting. Also, in areas where the resolution of LiDAR data is poor, field reconnaissance, coupled with topographic maps and aerial photographs, permits a more accurate location of fault-related geomorphic features. LiDAR images are extremely valuable as a base for field mapping in this heavily forested area, and the use of LiDAR is far superior to traditional mapping techniques relying only on aerial photography and 7.5 minute USGS quadrangle topographic maps. Comparison with earlier mapping of the northern San Andreas fault (Brown and Wolfe, 1972) shows that in some areas the LiDAR data allow a correction of the fault trace location of up to several hundred meters. To date we have field checked approximately 24 km of the 70-km-long section of the fault for which LiDAR data is available. The remaining 46 km will be field checked in 2005. The result will be a much more accurate map of the active traces of the northern San Andreas Fault, which will be of great use for future fault studies.

Impact of 1985 hurricanes on Isles Dernieres, Louisiana: Temporal and spatial analysis of coastal geomorphic changes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debusshere, K.; Westphal, K.; Penland, S.

1989-09-01

Catastrophic geomorphic changes occurred in the Isles Dernieres barrier island arc as a result of the direct impact of three hurricanes in 1985. The severity of the impact of hurricanes Danny, Elena, and Juan had not been equaled since the landfall of hurricanes Betsy and Camille in the late 1960s. The Isles Dernieres had not been subjected to a direct hurricane landfall since hurricane Bob in 1979. The recent hurricane impacts provided the USGS/LGS Louisiana Cooperative Barrier Island and Land Loss Study the opportunity to examine the process-response characteristics of this low-profile transgressive barrier island arc to multiple hurricane impactsmore » in a single hurricane season. The geomorphic changes along the Isles Dernieres were determined using four sequential airborne videotape surveys acquired in July 1984, July 1985 (pre-storm), August 1985 (post-Danny) and November 1985 (post-Juan) and mapped on 1:24,000 base maps produced from concurrent vertical aerial photography. A coastal geomorphic classification was developed to describe, quantify, and map the alongshore geomorphic, sedimentologic , and vegetative character of this barrier shoreline. The classification consists of three levels of descriptors: (1) primary morphology to define the predominant longshore morphology, (2) modifiers to depict the small-scale longshore features, and (3) variants to locate and quantify important coastal features, not mappable at the scale used.« less

Mapping process and age of Quaternary deposits on Santa Rosa Island, Channel Islands National Park, California

NASA Astrophysics Data System (ADS)

Schmidt, K. M.; Minor, S. A.; Bedford, D.

2016-12-01

Employing a geomorphic process-age classification scheme, we mapped the Quaternary surficial geology of Santa Rosa (SRI) within the Channel Islands National Park. This detailed (1:12,000 scale) map represents upland erosional transport processes and alluvial, fluvial, eolian, beach, marine terrace, mass wasting, and mixed depositional processes. Mapping was motivated through an agreement with the National Park Service and is intended to aid natural resource assessments, including post-grazing disturbance recovery and identification of mass wasting and tectonic hazards. We obtained numerous detailed geologic field observations, fossils for faunal identification as age control, and materials for numeric dating. This GPS-located field information provides ground truth for delineating map units and faults using GIS-based datasets- high-resolution (sub-meter) aerial imagery, LiDAR-based DEMs and derivative raster products. Mapped geologic units denote surface processes and Quaternary faults constrain deformation kinematics and rates, which inform models of landscape change. Significant findings include: 1) Flights of older Pleistocene (>120 ka) and possibly Pliocene marine terraces were identified beneath younger alluvial and eolian deposits at elevations as much as 275 m above modern sea level. Such elevated terraces suggest that SRI was a smaller, more submerged island in the late Neogene and (or) early Pleistocene prior to tectonic uplift. 2) Structural and geomorphic observations made along the potentially seismogenic SRI fault indicate a protracted slip history during the late Neogene and Quaternary involving early normal slip, later strike slip, and recent reverse slip. These changes in slip mode explain a marked contrast in island physiography across the fault. 3) Many of the steeper slopes are dramatically stripped of regolith, with exposed bedrock and deeply incised gullies, presumably due effects related to past grazing practices. 4) Surface water presence is spatially discontinuous and correlated with major fault traces and geologic unit boundaries.

Mapping the Riverscape of the Middle Fork John Day River with Structure-from-Motion

NASA Astrophysics Data System (ADS)

Dietrich, J. T.

2014-12-01

Aerial photography has proven an efficient method to collect a wide range of continuous variables for large sections of rivers. These data include variables such as the planimetric shape, low-flow and bank-full widths, bathymetry, and sediment sizes. Mapping these variables in a continuous manner allows us to explore the heterogeneity of the river and build a more complete picture of the holistic riverscape. To explore a low-cost option for aerial photography and riverscape mapping, I used the combination of a piloted helicopter and an off-the-shelf digital SLR camera to collect aerial imagery for a 32 km segment of the Middle Fork John Day River in eastern Oregon. This imagery was processed with Structure-from-Motion (SfM) photogrammetry to produce high-resolution 10 cm orthophotos and digital surface models that were used to extract riverscape variables. The Middle Fork John Day River is an important spawning river for anadromous Chinnook and Steelhead and has been the focus of widespread restoration and conservation activities in response to the legacies of extensive grazing and mining activity. By mapping the riverscape of the Middle Fork John Day, I explored downstream relationships between several geomorphic variables with hyperscale analysis. These riverscape data also provided an opportunity to make a continuous map of habitat suitability for migrating adult Chinook. Both the geomorphic and habitat suitability analysis provide an important assessment of the natural variation in the river and the impact of human modification, both positive and negative.

Using focal mechanism solutions to correlate earthquakes with faults in the Lake Tahoe-Truckee area, California and Nevada, and to help design LiDAR surveys for active-fault reconnaissance

NASA Astrophysics Data System (ADS)

Cronin, V. S.; Lindsay, R. D.

2011-12-01

Geomorphic analysis of hillshade images produced from aerial LiDAR data has been successful in identifying youthful fault traces. For example, the recently discovered Polaris fault just northwest of Lake Tahoe, California/Nevada, was recognized using LiDAR data that had been acquired by local government to assist land-use planning. Subsequent trenching by consultants under contract to the US Army Corps of Engineers has demonstrated Holocene displacement. The Polaris fault is inferred to be capable of generating a magnitude 6.4-6.9 earthquake, based on its apparent length and offset characteristics (Hunter and others, 2011, BSSA 101[3], 1162-1181). Dingler and others (2009, GSA Bull 121[7/8], 1089-1107) describe paleoseismic or geomorphic evidence for late Neogene displacement along other faults in the area, including the West Tahoe-Dollar Point, Stateline-North Tahoe, and Incline Village faults. We have used the seismo-lineament analysis method (SLAM; Cronin and others, 2008, Env Eng Geol 14[3], 199-219) to establish a tentative spatial correlation between each of the previously mentioned faults, as well as with segments of the Dog Valley fault system, and one or more earthquake(s). The ~18 earthquakes we have tentatively correlated with faults in the Tahoe-Truckee area occurred between 1966 and 2008, with magnitudes between 3 and ~6. Given the focal mechanism solution for a well-located shallow-focus earthquake, the nodal planes can be projected to Earth's surface as represented by a DEM, plus-or-minus the vertical and horizontal uncertainty in the focal location, to yield two seismo-lineament swaths. The trace of the fault that generated the earthquake is likely to be found within one of the two swaths [1] if the fault surface is emergent, and [2] if the fault surface is approximately planar in the vicinity of the focus. Seismo-lineaments from several of the earthquakes studied overlap in a manner that suggests they are associated with the same fault. The surface trace of both the Polaris fault and the Dog Valley fault system are within composite swaths defined by overlapping seismo-lineaments. Composite seismo-lineaments indicate that multiple historic earthquakes might be associated with a fault. This apparently successful correlation of earthquakes with faults in an area where geologic mapping is good suggests another use for SLAM in areas where fault mapping is incomplete, inadequate or made particularly difficult because of vegetative cover. If no previously mapped fault exists along a composite swath generated using well constrained focal mechanism solutions, the swath might be used to guide the design of a LiDAR survey in support of reconnaissance for the causative fault. The acquisition and geomorphic analysis of LiDAR data along a compound seismo-lineament swath might reveal geomorphic evidence of a previously unrecognized fault trace that is worthy of additional field study.

The Development of 3d Sub-Surface Mapping Scheme and its Application to Martian Lobate Debris Aprons

NASA Astrophysics Data System (ADS)

Baik, H.; Kim, J.

2017-07-01

The Shallow Subsurface Radar (SHARAD), a sounding radar equipped on the Mars Reconnaissance Orbiter (MRO), has produced highly valuable information about the Martian subsurface. In particular, the complicated substructures of Mars such as polar deposit, pedestal crater and the other geomorphic features involving possible subsurface ice body has been successfully investigated by SHARAD. In this study, we established a 3D subsurface mapping strategy employing the multiple SHARAD profiles. A number of interpretation components of SHARAD signals were integrated into a subsurface mapping scheme using radargram information and topographic data, then applied over a few mid latitude Lobate Debris Aprons (LDAs). From the identified subsurface layers of LDA, and the GIS data base incorporating the other interpretation outcomes, we are expecting to trace the origin of LDAs. Also, the subsurface mapping scheme developed in this study will be further applied to other interesting Martian geological features such as inter crater structures, aeolian deposits and fluvial sediments. To achieve higher precision sub-surface mapping, the clutter simulation employing the high resolution topographic data and the upgraded clustering algorithms assuming multiple sub-surface layers will be also developed.

Interpretation of recent alpine landscape system evolution using geomorphic mapping and L-band InSAR analyses

NASA Astrophysics Data System (ADS)

Imaizumi, Fumitoshi; Nishiguchi, Takaki; Matsuoka, Norikazu; Trappmann, Daniel; Stoffel, Markus

2018-06-01

Alpine landscapes are typically characterized by inherited features of past glaciations and, for the more recent past, by the interplay of a multitude of types of geomorphic processes, including permafrost creep, rockfalls, debris flows, and landslides. These different processes usually exhibit large spatial and temporal variations in activity and velocity. The understanding of these processes in a wide alpine area is often hindered by difficulties in their surveying. In this study, we attempt to disentangle recent changes in an alpine landscape system using geomorphic mapping and L-band DInSAR analyses (ALOS-PALSAR) in the Zermatt Valley, Swiss Alps. Geomorphic mapping points to a preferential distribution of rock glaciers on north-facing slopes, whereas talus slopes are concentrated on south-facing slopes. Field-based interpretation of ground deformation in rock glaciers and movements in talus slopes correlates well with the ratio of InSAR images showing potential ground deformation. Moraines formed during the Little Ice Age, rock glaciers, and talus slopes on north-facing slopes are more active than landforms on south-facing slopes, implying that the presence of permafrost facilitates the deformation of these geomorphic units. Such deformations of geomorphic units prevail also at the elevation of glacier termini. For rock cliffs, the ratio of images indicating retreat is affected by slope orientation and elevation. Linkages between sediment supply from rock cliffs and sediment transport in torrents are different among tributaries, affected by relative locations between sediment supply areas and the channel network. We conclude that the combined use of field surveys and L-band DInSAR analyses can substantially improve process understanding in steep, high-mountain terrain.

Geomorphic and geologic controls of geohazards induced by Nepal's 2015 Gorkha earthquake.

PubMed

Kargel, J S; Leonard, G J; Shugar, D H; Haritashya, U K; Bevington, A; Fielding, E J; Fujita, K; Geertsema, M; Miles, E S; Steiner, J; Anderson, E; Bajracharya, S; Bawden, G W; Breashears, D F; Byers, A; Collins, B; Dhital, M R; Donnellan, A; Evans, T L; Geai, M L; Glasscoe, M T; Green, D; Gurung, D R; Heijenk, R; Hilborn, A; Hudnut, K; Huyck, C; Immerzeel, W W; Liming, Jiang; Jibson, R; Kääb, A; Khanal, N R; Kirschbaum, D; Kraaijenbrink, P D A; Lamsal, D; Shiyin, Liu; Mingyang, Lv; McKinney, D; Nahirnick, N K; Zhuotong, Nan; Ojha, S; Olsenholler, J; Painter, T H; Pleasants, M; Pratima, K C; Yuan, Q I; Raup, B H; Regmi, D; Rounce, D R; Sakai, A; Donghui, Shangguan; Shea, J M; Shrestha, A B; Shukla, A; Stumm, D; van der Kooij, M; Voss, K; Xin, Wang; Weihs, B; Wolfe, D; Lizong, Wu; Xiaojun, Yao; Yoder, M R; Young, N

2016-01-08

The Gorkha earthquake (magnitude 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9000 people and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes' induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision-makers. We mapped 4312 coseismic and postseismic landslides. We also surveyed 491 glacier lakes for earthquake damage but found only nine landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions. Copyright © 2016, American Association for the Advancement of Science.

Geomorphic and Geologic Controls of Geohazards induced by Nepal's 2015 Gorkha Earthquake

NASA Technical Reports Server (NTRS)

Kargel, J. S.; Leonard, G. J.; Shugar, D. H.; Haritashya, U.K.; Bevington, A.; Fielding, E. J.; Fujita, K.; Geertsema, M.; Miles, E. S.; Steiner, J.;

Aircraft and satellite remote sensing of desert soils and landscapes

NASA Technical Reports Server (NTRS)

Petersen, G. W.; Connors, K. F.; Miller, D. A.; Day, R. L.; Gardner, T. W.

1987-01-01

Remote sensing data on desert soils and landscapes, obtained by the Landsat TM, Heat Capacity Mapping Mission (HCMM), Simulated SPOT, and Thermal IR Multispectral Scanner (TIMS) aboard an aircraft, are discussed together with the analytical techniques used in the studies. The TM data for southwestern Nevada were used to discriminate among the alluvial fan deposits with different degrees of desert pavement and varnish, and different vegetation cover. Thermal-IR data acquired from the HCMM satellite were used to map the spatial distribution of diurnal surface temperatures and to estimate mean annual soil temperatures in central Utah. Simulated SPOT data for northwestern New Mexico identified geomorphic features, such as differences in eolian sand cover and fluvial incision, while the TIMS data depicted surface geologic features of the Saline Valley in California.

Active Structures as Deduced from Geomorphic Features: A case in Hsinchu Area, northwestern Taiwan

NASA Astrophysics Data System (ADS)

Chen, Y.; Shyu, J.; Ota, Y.; Chen, W.; Hu, J.; Tsai, B.; Wang, Y.

2002-12-01

Hsinchu area is located in the northwestern Taiwan, the fold-and thrust belt created by arc-continent collision between Eurasian and Philippine. Since the collision event is still ongoing, the island is tectonically active and full of active faults. According to the historical records, some of the faults are seismically acting. In Hsinchuarea two active faults, the Hsinchu and Hsincheng, have been previously mapped. To evaluate the recent activities, we studied the related geomorphic features by using newly developed Digital Elevation Model (DEM), the aerial photos and field investigation. Geologically, both of the faults are coupled with a hanging wall anticline. The anticlines are recently active due to the deformation of the geomorphic surfaces. The Hsinchu fault system shows complicate corresponding scarps, distributed sub-parallel to the fault trace previously suggested by projection of subsurface geology. This is probably caused by its strike-slip component tearing the surrounding area along the main trace. The scarps associated with the Hsincheng fault system are rather simple and unique. It offsets a flight of terraces all the way down to recent flood plain, indicating its long lasting activity. One to two kilometers to east of main trace a back-thrust is found, showing coupled vertical surface offsets with the main fault. The striking discovery in this study is that the surface deformation is only distributed in the southern bank of Touchien river, also suddenly decreasing when crossing another tear fault system, which is originated from Hsincheng fault in the west and extending southeastward parallel to the Touchien river. The strike-slip fault system mentioned above not only bisects the Hsinchu fault, but also divides the Hsincheng fault into segments. The supporting evidence found in this study includes pressure ridges and depressions. As a whole, the study area is tectonically dominated by three active fault systems and two actively growing anticlines. The interactions between active structural systems formed the complicate geomorphic features presented in this paper.

Geomorphic adjustment to hydrologic modifications along a meandering river: Implications for surface flooding on a floodplain

NASA Astrophysics Data System (ADS)

Edwards, Brandon L.; Keim, Richard F.; Johnson, Erin L.; Hupp, Cliff R.; Marre, Saraline; King, Sammy L.

2016-09-01

Responses of large regulated rivers to contemporary changes in base level are not well understood. We used field measurements and historical analysis of air photos and topographic maps to identify geomorphic trends of the lower White River, Arkansas, USA, in the 70 years following base-level lowering at its confluence with the Mississippi River and concurrent with flood control by dams. Incision was identified below a knickpoint area upstream of St. Charles, AR, and increases over the lowermost 90 km of the study site to 2 m near the confluence with the Mississippi River. Mean bankfull width increased by 30 m (21%) from 1930 to 2010. Bank widening appears to be the result of flow regulation above the incision knickpoint and concomitant with incision below the knickpoint. Hydraulic modeling indicated that geomorphic adjustments likely reduced flooding by 58% during frequent floods in the incised, lowermost floodplain affected by backwater flooding from the Mississippi River and by 22% above the knickpoint area. Dominance of backwater flooding in the incised reach indicates that incision is more important than flood control on the lower White River in altering flooding and also suggests that the Mississippi River may be the dominant control in shaping the lower floodplain. Overall, results highlight the complex geomorphic adjustment in large river-floodplain systems in response to anthropogenic modifications and their implications, including reduced river-floodplain connectivity.

Geomorphic Mapping and Paleoterrain Generation for use in Modeling Holocene (8,000 1,500 yr) Agropastoral Landuse and Landscape Interactions in Southeast Spain

NASA Astrophysics Data System (ADS)

Arrowsmith, J. R.; Dimaggio, E. N.; Barton, C. M.; Sarjoughian, H. S.; Fall, P.; Falconer, S. E.; Ullah, I. I.

2006-12-01

Dramatic changes in land use were associated with the rise of agriculture in the mid Holocene. Both the surface properties and the drainage networks were changed. Along with the direct modifications to surface properties (vegetation change, sediment liberation, and compaction) and drainage network alteration (terracing, canals), up and downstream responses in the watersheds communicated these changes throughout the landscape. The magnitude, rate, and feedbacks with the growing human populations are critical questions in our effort to assess human-landscape interactions. Our interdisciplinary team has focused on two field sites around the Mediterranean for model development and testing. We are combining high resolution process- based models of landscape change implemented within the GRASS GIS with agent based models of agropastoral behavior and driven by high resolution climate and vegetation models. In the Spanish field area (Penaguila Valley, 38.41 N 0.23 W), we have produced detailed (1:10,000) geomorphic maps which we combine with high resolution Digital Elevation Models (DEMs) on which we can run the surface process models to assess the portions of the landscape that are most sensitive to the postulated agropastoral landuse changes. To support this modeling we have produced the 1 m DEMs from softcopy photogrammetry. This DEM has greatly improved our overall spatial resolution to permit more accurate terrace correlations and improved quantitative assessment of morphologic processes (e.g. channel erosion, slope stability). In stereo, we have mapped overall landscape morphology that emphasizes areas of active erosion and alluvial terrace surfaces. Alluvial terraces are crucial to this research because they record periods of past stable topography and those of mid Holocene age were settled and farmed. We have correlated mapped terraces across the landscape using elevation and morphological distinctions. Using ArcGIS, we interpolated surfaces across equivalent terraces using triangulated irregular networks (TINs) allowing reconstruction of multiple regional landscapes to establish a chronosequence of absolute landscape change. This mapping and reconstruction will be field checked and numerical age constraints applied. Interestingly, our tentative age assessment of the lowest broad surface indicates that it was occupied about 5 ka, and now has been incised by 20 m. Archeological sites have been cut by the incision. This change from a broad low relief alluvial surface to one cut by narrow channels may have been an important change for the local populations and caused them to change their behaviors, even though it may have been initially triggered by distributed landscape change in the watershed, due to agropastoral activities.

Surficial Geologic Map of the Ashby-Lowell-Sterling-Billerica 11-Quadrangle Area in Northeast-Central Massachusetts

USGS Publications Warehouse

Stone, Byron D.; Stone, Janet R.

2007-01-01

The surficial geologic map shows the distribution of nonlithified earth materials at land surface in an area of eleven 7.5-minute quadrangles (total 505 mi2) in northeast-central Massachusetts. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic features, stratigraphic relationships, and age. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for water resources, construction aggregate resources, earth-surface hazards assessments, and land-use decisions. This compilation of surficial geologic materials is an interim product that defines the areas of exposed bedrock, and the boundaries between glacial till, glacial stratified deposits, and overlying postglacial deposits. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text (PDF), a regional map at 1:50,000 scale (PDF), quadrangle maps at 1:24,000 scale (PDF files), GIS data layers (ArcGIS shapefiles), metadata for the GIS layers, scanned topographic base maps (TIF), and a readme.txt file.

Surficial Geologic Map of the Salem Depot-Newburyport East-Wilmington-Rockport 16-Quadrangle Area in Northeast Massachusetts

USGS Publications Warehouse

Stone, Byron D.; Stone, Janet Radway; DiGiacomo-Cohen, Mary L.

2006-01-01

The surficial geologic map shows the distribution of nonlithified earth materials at land surface in an area of 16 7.5-minute quadrangles (total 658 mi2) in northeast Massachusetts. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (grain size, sedimentary structures, mineral and rock-particle composition), constructional geomorphic features, stratigraphic relationships, and age. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for water resources, construction aggregate resources, earth-surface hazards assessments, and land-use decisions. This compilation of surficial geologic materials is an interim product that defines the areas of exposed bedrock, and the boundaries between glacial till, glacial stratified deposits, and overlying postglacial deposits. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text (PDF), a regional map at 1:50,000 scale (PDF), quadrangle maps at 1:24,000 scale (PDF files), GIS data layers (ArcGIS shapefiles), metadata for the GIS layers, scanned topographic base maps (TIF), and a readme.txt file.

Surficial Geologic Map of the Pocasset-Provincetown-Cuttyhunk-Nantucket 24-Quadrangle Area of Cape Cod and Islands, Southeast Massachusetts

USGS Publications Warehouse

Stone, Byron D.; DiGiacomo-Cohen, Mary L.

2006-01-01

The surficial geologic map layer shows the distribution of nonlithified earth materials at land surface in an area of 24 7.5-minute quadrangles (555 mi2 total) in southeast Massachusetts. Across Massachusetts, these materials range from a few feet to more than 500 ft in thickness. They overlie bedrock, which crops out in upland hills and as resistant ledges in valley areas. On Cape Cod and adjacent islands, these materials completely cover the bedrock surface. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic features, stratigraphic relations, and age. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for assessing water resources, construction aggregate resources, and earth-surface hazards, and for making land-use decisions. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text (PDF), quadrangle maps at 1:24,000 scale (PDF files), GIS data layers (ArcGIS shapefiles), metadata for the GIS layers, scanned topographic base maps (TIF), and a readme.txt file.

Geomorphic domains and linear features on Landsat images, Circle Quadrangle, Alaska

USGS Publications Warehouse

Simpson, S.L.

1984-01-01

A remote sensing study using Landsat images was undertaken as part of the Alaska Mineral Resource Assessment Program (AMRAP). Geomorphic domains A and B, identified on enhanced Landsat images, divide Circle quadrangle south of Tintina fault zone into two regional areas having major differences in surface characteristics. Domain A is a roughly rectangular, northeast-trending area of relatively low relief and simple, widely spaced drainages, except where igneous rocks are exposed. In contrast, domain B, which bounds two sides of domain A, is more intricately dissected showing abrupt changes in slope and relatively high relief. The northwestern part of geomorphic domain A includes a previously mapped tectonostratigraphic terrane. The southeastern boundary of domain A occurs entirely within the adjoining tectonostratigraphic terrane. The sharp geomorphic contrast along the southeastern boundary of domain A and the existence of known faults along this boundary suggest that the southeastern part of domain A may be a subdivision of the adjoining terrane. Detailed field studies would be necessary to determine the characteristics of the subdivision. Domain B appears to be divisible into large areas of different geomorphic terrains by east-northeast-trending curvilinear lines drawn on Landsat images. Segments of two of these lines correlate with parts of boundaries of mapped tectonostratigraphic terranes. On Landsat images prominent north-trending lineaments together with the curvilinear lines form a large-scale regional pattern that is transected by mapped north-northeast-trending high-angle faults. The lineaments indicate possible lithlogic variations and/or structural boundaries. A statistical strike-frequency analysis of the linear features data for Circle quadrangle shows that northeast-trending linear features predominate throughout, and that most northwest-trending linear features are found south of Tintina fault zone. A major trend interval of N.64-72E. in the linear feature data, corresponds to the strike of foliations in metamorphic rocks and magnetic anomalies reflecting compositional variations suggesting that most linear features in the southern part of the quadrangle probably are related to lithologic variations brought about by folding and foliation of metamorphic rocks. A second important trend interval, N.14-35E., may be related to thrusting south of the Tintina fault zone, as high concentrations of linear features within this interval are found in areas of mapped thrusts. Low concentrations of linear features are found in areas of most igneous intrusives. High concentrations of linear features do not correspond to areas of mineralization in any consistent or significant way that would allow concentration patterns to be easily used as an aid in locating areas of mineralization. The results of this remote sensing study indicate that there are several possibly important areas where further detailed studies are warranted.

Geomorphic Flood Area (GFA): a DEM-based tool for flood susceptibility mapping at large scales

NASA Astrophysics Data System (ADS)

Manfreda, S.; Samela, C.; Albano, R.; Sole, A.

2017-12-01

Flood hazard and risk mapping over large areas is a critical issue. Recently, many researchers are trying to achieve a global scale mapping encountering several difficulties, above all the lack of data and implementation costs. In data scarce environments, a preliminary and cost-effective floodplain delineation can be performed using geomorphic methods (e.g., Manfreda et al., 2014). We carried out several years of research on this topic, proposing a morphologic descriptor named Geomorphic Flood Index (GFI) (Samela et al., 2017) and developing a Digital Elevation Model (DEM)-based procedure able to identify flood susceptible areas. The procedure exhibited high accuracy in several test sites in Europe, United States and Africa (Manfreda et al., 2015; Samela et al., 2016, 2017) and has been recently implemented in a QGIS plugin named Geomorphic Flood Area (GFA) - tool. The tool allows to automatically compute the GFI, and turn it into a linear binary classifier capable of detecting flood-prone areas. To train this classifier, an inundation map derived using hydraulic models for a small portion of the basin is required (the minimum is 2% of the river basin's area). In this way, the GFA-tool allows to extend the classification of the flood-prone areas across the entire basin. We are also defining a simplified procedure for the estimation of the river depth, which may be helpful for large-scale analyses to approximatively evaluate the expected flood damages in the surrounding areas. ReferencesManfreda, S., Nardi, F., Samela, C., Grimaldi, S., Taramasso, A. C., Roth, G., & Sole, A. (2014). Investigation on the use of geomorphic approaches for the delineation of flood prone areas. J. Hydrol., 517, 863-876. Manfreda, S., Samela, C., Gioia, A., Consoli, G., Iacobellis, V., Giuzio, L., & Sole, A. (2016). Flood-prone areas assessment using linear binary classifiers based on flood maps obtained from 1D and 2D hydraulic models. Nat. Hazards, Vol. 79 (2), pp 735-754. Samela, C., Manfreda, S., Paola, F. D., Giugni, M., Sole, A., & Fiorentino, M. (2016). DEM-Based Approaches for the Delineation of Flood-Prone Areas in an Ungauged Basin in Africa. J. Hydrol. Eng,, 06015010. Samela, C., Troy, T. J., & Manfreda, S. (2017a). Geomorphic classifiers for flood-prone areas delineation for data-scarce environments. Adv. Water Resour., 102, 13-28.

Characterizing the geomorphic setting of precariously balanced rocks using terrestrial laser scanning technology

NASA Astrophysics Data System (ADS)

Haddad, D. E.; Arrowsmith, R.

2009-12-01

Terrestrial laser scanning (TLS) technology is rapidly becoming an effective three-dimensional imaging tool. Precariously balanced rocks are a subset of spheroidally weathered boulders. They are balanced on bedrock pedestals and are formed in upland drainage basins and pediments of exhumed plutons. Precarious rocks are used as negative evidence of earthquake-driven extreme ground motions. Field surveys of PBRs are coupled with cosmogenic radionuclide (CRN) surface exposure dating techniques to determine their exhumation rates. These rates are used in statistical simulations to estimate the magnitudes and recurrences of earthquake-generated extreme ground shaking as a means to physically validate seismic hazard analyses. However, the geomorphic setting of PBRs in the landscape is poorly constrained when interpreting their exhumation rates from CRN surface exposure dates. Are PBRs located on steep or gentle hillslopes? Are they located near drainages or hillslope crests? What geomorphic processes control the spatial distribution of PBRs in a landscape, and where do these processes dominate? Because the fundamental hillslope transport laws are largely controlled by local hillslope gradient and contributing area, the location of a PBR is controlled by the geomorphic agents and their rates acting on it. Our latest efforts involve using a combination of TLS and airborne laser swath mapping (ALSM) to characterize the geomorphic situation of PBRs. We used a Riegl LPM 800i (LPM 321) terrestrial laser scanner to scan a ~1.5 m tall by ~1 m wide precariously balanced rock in the Granite Dells, central Arizona. The PBR was scanned from six positions, and the scans were aligned to a point cloud totaling 3.4M points. We also scanned a ~50 m by ~150 m area covering PBR hillslopes from five scan positions. The resulting 5.5M points were used to create a digital terrain model of precarious rocks and their hillslopes. Our TLS- and ALSM-generated surface models and DEMs provide a unique opportunity to understand the roles of hillslope-scale geomorphic processes in the PBR life cycle. Initial results show that the studied PBRs are located near hillslope crests ~33 m above the nearest drainages and on slopes >17°. No PBRs were found on gentle slopes adjacent to channels, suggesting that hillslope crests are conducive to preserving PBRs. Understanding these landscape morphometrics for precarious rock zones is critical to building our confidence in interpreting PBR exhumation rates from CRN dating techniques, thus improving the evaluation of seismic hazard analyses.

The geomorphic evolution of the lunar surface.

NASA Technical Reports Server (NTRS)

Ronca, L. B.

1972-01-01

The solution of the function relating craters of the continuous degradation sequence with degree of erosion was defined as the geomorphic index of the area. Studies of the geomorphic index of stratigraphic surfaces show that areas covered by considerable ballistic sediments have a geomorphic index which is not a monotonic function of time. On the other hand, areas covered almost exclusively by mare flooding show an index which is a monotonic function of the age of the flooding. As each mare surface shows a considerable range in indices, it is concluded that maria are covered by surfaces formed through a considerable length of time. By using Apollo 11 and 12 radiometric ages it is suggested that the time of mare flooding lasted on the order of one billion years. The geomorphic index of highland surfaces shows a remarkable degree of order - i.e., the farther an area is inland from the mare shores, the higher will be the index. No explanation is given for this phenomenon, but it is suggested that lunar erosion is not just a localized phenomenon centered on the locus of an impact, but has lateral trends of regional dimensions.

Tracking Geomorphic Signatures of Watershed Suburbanization with Multi-Temporal LiDAR

EPA Science Inventory

Urban development practices redistribute surface materials through filling, grading and terracing, causing drastic changes to the geomorphic organization of the landscape. Many studies document the hydrologic, biologic, or geomorphic consequences of urbanization using space-for-t...

Comparison of Terrestrial Laser Scanning (TLS) and Structure from Motion (SfM) photogrammetry from unmanned aerial systems (UAS) for geomorphic change detection in beach-dune systems.

NASA Astrophysics Data System (ADS)

Heathfield, D.; Walker, I. J.; Grilliot, M. J.

2016-12-01

The recent emergence of terrestrial laser scanning (TLS) and unmanned aerial systems (UAS) as mapping platforms in geomorphology research has allowed for expedited acquisition of high spatial and temporal resolution, three-dimensional topographic datasets. TLS provides dense 3D `point cloud' datasets that require careful acquisition strategies and appreciable post-processing to produce accurate digital elevation models (DEMs). UAS provide overlapping nadir and oblique imagery that can be analysed using Structure from Motion (SfM) photogrammetry software to provide accurate, high-resolution orthophoto mosaics and accurate digital surface models (DSMs). Both methods yield centimeter to decimeter scale accuracy, depending on various hardware and field acquisition considerations (e.g., camera resolution, flight height, on-site GNSS control, etc.). Combined, the UAS-SfM workflow provides a comparable and more affordable solution to the more expensive TLS or aerial LiDAR methods. This paper compares and contrasts SfM and TLS survey methodologies and related workflow costs and benefits as used to quantify and examine seasonal beach-dune erosion and recovery processes at a site (Calvert Island) on British Columbia's central coast in western Canada. Seasonal SfM- and TLS-derived DEMs were used to quantify spatial patterns of surface elevation change, geomorphic responses, and related significant sediment volume changes. Cluster maps of positive (depositional) and negative (erosional) change are analysed to detect and interpret the geomorphic and sediment budget responses following an erosive water level event during winter 2016 season (Oct. 2015 - Apr. 2016). Vantage cameras also provided qualitative data on the frequency and magnitude of environmental drivers (e.g., tide, wave, wind forcing) of erosion and deposition events during the observation period. In addition, we evaluate the costs, time expenditures, and accuracy considerations for both SfM and TLS methodologies.

Large Scale Geomorphic Mapping of Cryoplanation Terraces in Central and Eastern Alaska

NASA Astrophysics Data System (ADS)

Queen, C.; Nyland, K. E.; Nelson, F. E.

2017-12-01

Cryoplanation terraces (CTs) are large periglacial landforms characterized by alternating treads and risers, giving the appearance of giant staircases ascending ridgecrests and hillsides. The risers (scarps) are typically covered with coarse clastic material, while the surfaces of the nearly planar treads are a mosaic of vegetation, rock debris, and surficial periglacial landforms. CTs are best developed in areas of moderate relief across Beringia, the largely unglaciated region between the Lena and Mackenzie rivers, including Bering Sea islands that were formerly highlands on the Bering Land Bridge. CTs are generally thought to develop through locally intensified weathering at the base of scarps by processes associated with late lying bodies of snow. This hypothesis has been the subject of much speculative literature, but until recently there have been few process-oriented field studies performed on them. The work reported here builds on foundational work by R. D. Reger, who inventoried and investigated a large number of CTs in central and western Alaska. The resultant large-scale (1:2000) maps of cryoplanation terraces at Eagle Summit and Mount Fairplay in east-central Alaska were created using traditional and GPS-based mapping methodologies. Pits were excavated at representative locations across treads to obtain information about subsurface characteristics. The resulting maps show the location and morphology of surficial geomorphic features on CT scarps, treads, and sideslopes, superimposed on high-resolution topographic maps and perspective diagrams. GIS-based analysis of the assembled map layers promotes three-dimensional understanding of the spatial relationships between CT morphology, material properties, and erosional processes, and provides key insights into intra- and inter- terrace relationships. In concert with relative and absolute dating of material on the landforms, this research is generally supportive of the "nivation hypothesis of CT development."

Geomorphic mapping to support river restoration on the Trinity River downstream from Lewiston Dam, California, 1980-2011

USGS Publications Warehouse

Curtis, Jennifer A.; Guerrero, Timothy M.

2015-01-01

Historic land use, dam construction, water storage, and flow diversions in the Trinity River watershed have resulted in downstream geomorphic change, loss of salmonid habitat, and declines in salmonid populations. The USGS in cooperation with the Trinity River Restoration Program, a multi-agency partnership tasked with implementing federally mandated restoration, completed a geomorphic change assessment to inform the planning process for future restoration work. This report documents an ARCMAP geodatabase (v.10.0) containing geomorphic features digitized from a series of rectified orthophotographs (http://dx.doi.org/10.5066/F7TT4P04). Upland, riparian, and channel features were digitized from six available base images (1980, 1997, 2001, 2006, 2009, and 2011). This report describes the structure of the geodatabase and the methods used to delineate individual geomorphic features.

Geomorphic Flood Area (GFA): a QGIS tool for a cost-effective delineation of the floodplains

NASA Astrophysics Data System (ADS)

Samela, Caterina; Albano, Raffaele; Sole, Aurelia; Manfreda, Salvatore

2017-04-01

The importance of delineating flood hazard and risk areas at a global scale has been highlighted for many years. However, its complete achievement regularly encounters practical difficulties, above all the lack of data and implementation costs. In conditions of scarce data availability (e.g. ungauged basins, large-scale analyses), a fast and cost-effective floodplain delineation can be carried out using geomorphic methods (e.g., Manfreda et al., 2011; 2014). In particular, an automatic DEM-based procedure has been implemented in an open-source QGIS plugin named Geomorphic Flood Area - tool (GFA - tool). This tool performs a linear binary classification based on the recently proposed Geomorphic Flood Index (GFI), which exhibited high classification accuracy and reliability in several test sites located in Europe, United States and Africa (Manfreda et al., 2015; Samela et al., 2016, 2017; Samela, 2016). The GFA - tool is designed to make available to all users the proposed procedure, that includes a number of operations requiring good geomorphic and GIS competences. It allows computing the GFI through terrain analysis, turning it into a binary classifier, and training it on the base of a standard inundation map derived for a portion of the river basin (a minimum of 2% of the river basin's area is suggested) using detailed methods of analysis (e.g. flood hazard maps produced by emergency management agencies or river basin authorities). Finally, GFA - tool allows to extend the classification outside the calibration area to delineate the flood-prone areas across the entire river basin. The full analysis has been implemented in this plugin with a user-friendly interface that should make it easy to all user to apply the approach and produce the desired results. Keywords: flood susceptibility; data scarce environments; geomorphic flood index; linear binary classification; Digital elevation models (DEMs). References Manfreda, S., Di Leo, M., Sole, A., (2011). Detection of Flood Prone Areas using Digital Elevation Models, Journal of Hydrologic Engineering, 16(10), 781-790. Manfreda, S., Nardi, F., Samela, C., Grimaldi, S., Taramasso, A. C., Roth, G., & Sole, A. (2014). Investigation on the Use of Geomorphic Approaches for the Delineation of Flood Prone Areas, Journal of Hydrology, 517, 863-876. Manfreda, S., Samela, C., Gioia, A., Consoli, G., Iacobellis, V., Giuzio, L., & Sole, A. (2015). Flood-prone areas assessment using linear binary classifiers based on flood maps obtained from 1D and 2D hydraulic models. Natural Hazards, Vol. 79 (2), pp 735-754. Samela, C. (2016), 100-year flood susceptibility maps for the continental U.S. derived with a geomorphic method. University of Basilicata. Dataset. Samela, C., Manfreda, S., Paola, F. D., Giugni, M., Sole, A., & Fiorentino, M. (2016). DEM-Based Approaches for the Delineation of Flood-Prone Areas in an Ungauged Basin in Africa. Journal of Hydrologic Engineering, 21(2), 1-10. Samela, C., Troy, T.J., Manfreda, S. (2017). Geomorphic classifiers for flood-prone areas delineation for data-scarce environments, Advances in Water Resources (under review).

Improving dust emission characterization in dust models using dynamic high-resolution geomorphic erodibility map

NASA Astrophysics Data System (ADS)

Parajuli, S. P.; Yang, Z.; Kocurek, G.

2013-12-01

Dust is known to affect the earth radiation budget, biogeochemical cycle, precipitation, human health and visibility. Despite the increased research effort, dust emission modeling remains challenging because dust emission is affected by complex geomorphological processes. Existing dust models overestimate dust emission and rely on tuning and a static erodibility factor in order to make simulated results comparable to remote sensing and ground-based observations. In most of current models, dust emission is expressed in terms of threshold friction speed, which ultimately depends mainly upon the percentage clay content and soil moisture. Unfortunately, due to the unavailability of accurate and high resolution input data of the clay content and soil moisture, estimated threshold friction speed commonly does not represent the variability in field condition. In this work, we attempt to improve dust emission characterization by developing a high resolution geomorphic map of the Middle East and North Africa (MENA), which is responsible for more than 50% of global dust emission. We develop this geomorphic map by visually examining high resolution satellite images obtained from Google Earth Pro and ESRI base map. Albeit subjective, our technique is more reliable compared to automatic image classification technique because we incorporate knowledge of geological/geographical setting in identifying dust sources. We hypothesize that the erodibility is unique for different geomorphic landforms and that it can be quantified by the correlation between observed wind speed and satellite retrieved aerosol optical depth (AOD). We classify the study area into several key geomorphological categories with respect to their dust emission potential. Then we quantify their dust emission potential using the correlation between observed wind speed and satellite retrieved AOD. The dynamic, high-resolution geomorphic erodibility map thus prepared will help to reduce the uncertainty in current dust models associated with poor characterization of dust sources. The baseline dust scheme used in this study is the Dust Entrainment and Deposition (DEAD) model, which is also a component of the community land model (CLM). Proposed improvements in the dust emission representation will help to better understand the accurate effect of dust on climate processes.

Coastal system mapping: a new approach to formalising and conceptualising the connectivity of large-scale coastal systems

NASA Astrophysics Data System (ADS)

French, J.; Burningham, H.; Whitehouse, R.

2010-12-01

The concept of the coastal sediment cell has proved invaluable as a basis for estimating sediment budgets and as a framework for coastal management. However, whilst coastal sediment cells are readily identified on compartmentalised coastlines dominated by beach-grade material, the cell concept is less suited to handling broader linkages between estuarine, coastal and offshore systems, and for incorporating longer-range suspended sediment transport. We present a new approach to the conceptualisation of large-scale coastal geomorphic systems based on a hierarchical classification of component landforms and management interventions and mapping of the interactions between them. Coastal system mapping is founded on a classification that identifies high-level landform features, low-level landform elements and engineering interventions. Geomorphic features define the large-scale organisation of a system and include landforms that define gross coastal configuration (e.g. headland, bay) as well as fluvial, estuarine and offshore sub-systems that exchange sediment with and influence the open coast. Detailed system structure is mapped out with reference to a larger set of geomorphic elements (e.g. cliff, dune, beach ridge). Element-element interactions define cross-shore linkages (conceptualised as hinterland, backshore and foreshore zones) and alongshore system structure. Both structural and non-structural engineering interventions are also represented at this level. Element-level mapping is rationalised to represent alongshore variation using as few elements as possible. System linkages include both sediment transfer pathways and influences not associated with direct mass transfer (e.g. effect of a jetty at an inlet). A formal procedure for capturing and graphically representing coastal system structure has been developed around free concept mapping software, CmapTools (http://cmap.ihmc.us). Appended meta-data allow geographic coordinates, data, images and literature pertaining to specific locations to be embedded in system maps. Exported maps can be analysed separately to quantify abundance of system components and their scales of interaction. Our approach is demonstrated for different scales and geomorphic contexts in the UK, including Alnmouth Bay (NE England; 15km), Lowestoft to Felixstowe (E England; 73km) and Cardigan Bay (Wales; 267km). Aerial imagery provides the primary basis for identifying features and elements and likely modes of interaction. This interpretation is then checked against relevant research literature and site data. Coastal system mapping is a kind of knowledge formalisation that generalises disparate sources of information (‘plain data’) into usable knowledge. Consensus-derived system maps are highly effective as a catalyst for structured discussion of geomorphic system behaviour and its implications for coastal management. They also function as a repository for results from quantitative analyses and modelling.

Geomorphically based predictive mapping of soil thickness in upland watersheds

NASA Astrophysics Data System (ADS)

Pelletier, Jon D.; Rasmussen, Craig

2009-09-01

The hydrologic response of upland watersheds is strongly controlled by soil (regolith) thickness. Despite the need to quantify soil thickness for input into hydrologic models, there is currently no widely used, geomorphically based method for doing so. In this paper we describe and illustrate a new method for predictive mapping of soil thicknesses using high-resolution topographic data, numerical modeling, and field-based calibration. The model framework works directly with input digital elevation model data to predict soil thicknesses assuming a long-term balance between soil production and erosion. Erosion rates in the model are quantified using one of three geomorphically based sediment transport models: nonlinear slope-dependent transport, nonlinear area- and slope-dependent transport, and nonlinear depth- and slope-dependent transport. The model balances soil production and erosion locally to predict a family of solutions corresponding to a range of values of two unconstrained model parameters. A small number of field-based soil thickness measurements can then be used to calibrate the local value of those unconstrained parameters, thereby constraining which solution is applicable at a particular study site. As an illustration, the model is used to predictively map soil thicknesses in two small, ˜0.1 km2, drainage basins in the Marshall Gulch watershed, a semiarid drainage basin in the Santa Catalina Mountains of Pima County, Arizona. Field observations and calibration data indicate that the nonlinear depth- and slope-dependent sediment transport model is the most appropriate transport model for this site. The resulting framework provides a generally applicable, geomorphically based tool for predictive mapping of soil thickness using high-resolution topographic data sets.

Correlation of LANDSAT lineaments with Devonian gas fields in Lawrence County, Ohio

NASA Technical Reports Server (NTRS)

Johnson, G. O.

1981-01-01

In an effort to locate sources of natural gas in Ohio, the fractures and lineaments in Black Devonian shale were measured by: (1) field mapping of joints, swarms, and fractures; (2) stereophotointerpretation of geomorphic lineaments with precise photoquads; and (3) by interpreting the linear features on LANDSAT images. All results were compiled and graphically represented on 1:250,000 scale maps. The geologic setting of Lawrence County was defined and a field fracture map was generated and plotted as rose patterns at the exposure site. All maps were compared, contrasted, and correlated by superimposing each over the other as a transparency. The LANDSAT lineaments had significant correlation with the limits of oil and gas producing fields. These limits included termination of field production as well as extensions to other fields. The lineaments represent real rock fractures with zones of increased permeability in the near surface bedrock.

Surficial Geologic Map of the Clinton-Concord-Grafton-Medfield 12-Quadrangle Area in East Central Massachusetts

USGS Publications Warehouse

Stone, Janet R.; Stone, Byron D.

2006-01-01

The surficial geologic map shows the distribution of nonlithified earth materials at land surface in an area of twelve 7.5-minute quadrangles (total 660 square miles) in east-central Massachusetts. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (grain size, sedimentary structures, mineral and rock-particle composition), constructional geomorphic features, stratigraphic relationships, and age. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for water resources, construction aggregate resources, earth-surface hazards assessments, and land-use decisions. This compilation of surficial geologic materials is an interim product that defines the areas of exposed bedrock, and the boundaries between glacial till, glacial stratified deposits, and overlying postglacial deposits. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text (PDF), a regional map at 1:50,000 scale (PDF), quadrangle maps at 1:24,000 scale (12 PDF files), GIS data layers (ArcGIS shapefiles), scanned topographic base maps (TIF), metadata for the GIS layers, and a readme.txt file.

Earthquake geology of Kashmir Basin and its implications for future large earthquakes

NASA Astrophysics Data System (ADS)

Shah, A. A.

2013-09-01

Two major traces of active thrust faults were identified in the Kashmir Basin (KB) using satellite images and by mapping active geomorphic features. The ~N130°E strike of the mapped thrust faults is consistent with the regional ~NE-SW convergence along the Indian-Eurasian collision zone. The ~NE dipping thrust faults have uplifted the young alluvial fan surfaces at the SW side of the KB. This created a major tectono-geomorphic boundary along the entire strike length of the KB that is characterised by (1) a low relief with sediment-filled sluggish streams to the SE and (2) an uplifted region, with actively flowing streams to the SW. The overall tectono-geomorphic expression suggests that recent activity along these faults has tilted the entire Kashmir valley towards NE. Further, the Mw 7.6 earthquake, which struck Northern Pakistan and Kashmir on 8 October 2005, also suggests a similar strike and NE dipping fault plane, which could indicate that the KB fault is continuous over a distance of ~210 km and connects on the west with the Balakot Bagh fault. However, the geomorphic and the structural evidences of such a structure are not very apparent on the north-west, which thus suggest that it is not a contiguous structure with the Balakot Bagh fault. Therefore, it is more likely that the KB fault is an independent thrust, a possible ramp on the Main Himalayan Thrust, which has uplifting the SW portion of the KB and drowning everything to the NE (e.g. Madden et al. 2011). Furthermore, it seems very likely that the KB fault could be a right stepping segment of the Balakot Bagh fault, similar to Riasi Thrust, as proposed by Thakur et al. (2010). The earthquake magnitude is measured by estimating the fault rupture parameters (e.g. Wells and Coppersmith in Bull Seismol Soc Am 84:974-1002, 1994). Therefore, the total strike length of the mapped KB fault is ~120 km and by assuming a dip of 29° (Avouac et al. in Earth Planet Sci Lett 249:514-528, 2006) and a down-dip limit of 20 km, a Mw of 7.6 is possible on this fault.

Continuous catchment-scale monitoring of geomorphic processes with a 2-D seismological array

NASA Astrophysics Data System (ADS)

Burtin, A.; Hovius, N.; Milodowski, D.; Chen, Y.-G.; Wu, Y.-M.; Lin, C.-W.; Chen, H.

2012-04-01

The monitoring of geomorphic processes during extreme climatic events is of a primary interest to estimate their impact on the landscape dynamics. However, available techniques to survey the surface activity do not provide a relevant time and/or space resolution. Furthermore, these methods hardly investigate the dynamics of the events since their detection are made a posteriori. To increase our knowledge of the landscape evolution and the influence of extreme climatic events on a catchment dynamics, we need to develop new tools and procedures. In many past works, it has been shown that seismic signals are relevant to detect and locate surface processes (landslides, debris flows). During the 2010 typhoon season, we deployed a network of 12 seismometers dedicated to monitor the surface processes of the Chenyoulan catchment in Taiwan. We test the ability of a two dimensional array and small inter-stations distances (~ 11 km) to map in continuous and at a catchment-scale the geomorphic activity. The spectral analysis of continuous records shows a high-frequency (> 1 Hz) seismic energy that is coherent with the occurrence of hillslope and river processes. Using a basic detection algorithm and a location approach running on the analysis of seismic amplitudes, we manage to locate the catchment activity. We mainly observe short-time events (> 300 occurrences) associated with debris falls and bank collapses during daily convective storms, where 69% of occurrences are coherent with the time distribution of precipitations. We also identify a couple of debris flows during a large tropical storm. In contrast, the FORMOSAT imagery does not detect any activity, which somehow reflects the lack of extreme climatic conditions during the experiment. However, high resolution pictures confirm the existence of links between most of geomorphic events and existing structures (landslide scars, gullies...). We thus conclude to an activity that is dominated by reactivation processes. It highlights the major interest of a seismic monitoring since it allows a detailed spatial and temporal survey of events that classic approaches are not able to observe. In the future, dense two dimensional seismological arrays will assess in real-time the landscape dynamics of an entire catchment, tracking sediments from slopes to rivers.

Soil-geomorphic significance of land surface characteristics in an arid mountain range, Mojave Desert, USA

USGS Publications Warehouse

Hirmas, D.R.; Graham, R.C.; Kendrick, K.J.

2011-01-01

Mountains comprise an extensive and visually prominent portion of the landscape in the Mojave Desert, California. Landform surface properties influence the role these mountains have in geomorphic processes such as dust flux and surface hydrology across the region. The primary goal of this study was to describe and quantify land surface properties of arid-mountain landforms as a step toward unraveling the role these properties have in soil-geomorphic processes. As part of a larger soil-geomorphic study, four major landform types were identified within the southern Fry Mountains in the southwestern Mojave Desert on the basis of topography and landscape position: mountaintop, mountainflank, mountainflat (intra-range low-relief surface), and mountainbase. A suite of rock, vegetation, and morphometric land surface characteristic variables was measured at each of 65 locations across the study area, which included an associated piedmont and playa. Our findings show that despite the variation within types, landforms have distinct land surface properties that likely control soil-geomorphic processes. We hypothesize that surface expression influences a feedback process at this site where water transports sediment to low lying areas on the landscape and wind carries dust and soluble salts to the mountains where they are washed between rocks, incorporated into the soil, and retained as relatively long-term storage. Recent land-based video and satellite photographs of the dust cloud emanating from the Sierra Cucapá Mountains in response to the 7.2-magnitude earthquake near Mexicali, Mexico, support the hypothesis that these landforms are massive repositories of dust.

Mapping geomorphic process domains to predict hillslope sediment size distribution using remotely-sensed data and field sampling, Inyo Creek, California

NASA Astrophysics Data System (ADS)

Leclere, S.; Sklar, L. S.; Genetti, J. R.

2014-12-01

The size distribution of sediments produced on hillslopes and supplied to channels depends on the geomorphic processes that weather, detach and transport rock fragments down slopes. Little in the way of theory or data is available to predict patterns in hillslope size distributions at the catchment scale from topographic and geologic maps. Here we use aerial imagery and a variety of remote sensing techniques to map and categorize geomorphic landscape units (GLUs) by inferred sediment production process regime, across the steep mountain catchment of Inyo Creek, eastern Sierra Nevada, California. We also use field measurements of particle size and local geomorphic attributes to test and refine GLU determinations. Across the 2 km of relief in this catchment, landcover varies from bare bedrock cliffs at higher elevations to vegetated, regolith-covered convex slopes at lower elevations. Hillslope gradient could provide a simple index of sediment production process, from rock spallation and landsliding at highest slopes, to tree-throw and other disturbance-driven soil production processes at lowest slopes. However, many other attributes are needed for a more robust predictive model, including elevation, curvature, aspect, drainage area, and color. We combine tools from ArcGIS, ERDAS Imagine and Envi with groundtruthing field work to find an optimal combination of attributes for defining sediment production GLUs. Key challenges include distinguishing: weathered from freshly eroded bedrock, boulders from intact bedrock, and landslide deposits from talus slopes. We take advantage of emerging technologies that provide new ways of conducting fieldwork and comparing field data to mapping solutions. In particular, cellphone GPS is approaching the accuracy of dedicated GPS systems and the ability to geo-reference photos simplifies field notes and increases accuracy of later map creation. However, the predictive power of the GLU mapping approach is limited by inherent uncertainty in remotely sensed data and aerial imagery. This work is a contribution toward the long-term goal of reliable and automated mapping of hillslope sediment size distributions for use in sediment budgets and hazard delineation, and for understanding the feedbacks between climate, erosion and topography that drive sediment production.

Recovery of perennial vegetation in military target sites in the eastern Mohave Desert, Arizona

USGS Publications Warehouse

Steiger, John W.; Webb, Robert H.

2000-01-01

The effect of the age of geomorphic surfaces on the recovery of desert vegetation in military target sites was studied in the Mohave and Cerbat Mountains of northwestern Arizona. The target sites were cleared of all vegetation during military exercises in 1942-1943 and have not been subsequently disturbed. The degree of recovery was measured by calculating percentage-similarity (PS) and correlation-coefficient indices on the basis of differences in cover, density, and volume of species growing in and out of each target site. PS values, ranging from 22.7 to 95.1 percent (100 percent = identical composition), indicate a wide range of recovery that is partially controlled by the edaphic properties of the geomorphic surfaces. Statistical analyses show a strong pattern that indicates a greater variability in the degree of recovery for sites on older surfaces than on younger surfaces and a weak pattern that indicates an inverse relation between the degree of recovery and geomorphic age. Comparisons of the different effects of target site construction on the edaphic characteristics of each target site provides an explanation for these patterns and suggests the soil properties critical to the recovery process. Statistically significant negative or positive response to disturbance for most species are independent of the age of the geomorphic surfaces; however, there is strong evidence for a shift in response for the common perennial species Acamptopappus sphaerocephalus, and to a lesser extent, Salazaria mexicana, Encelia farinosa, and Coldenia canescens, among different geomorphic surfaces.

Are the benches at Mormon Point, Death Valley, California, USA, scarps or strandlines?

USGS Publications Warehouse

Knott, J.R.; Tinsley, J. C.; Wells, S.G.

2002-01-01

The benches and risers at Mormon Point, Death Valley, USA, have long been interpreted as strandlines cut by still-stands of pluvial lakes correlative with oxygen isotope stage (OIS) 5e/6 (120,000-186,000 yr B.P.) and OIS-2 (10,000-35,000 yr B.P.). This study presents geologic mapping and geomorphic analyses (Gilbert's criteria, longitudinal profiles), which indicate that only the highest bench at Mormon Point (~90 m above mean sea level (msl)) is a lake strandline. The other prominent benches on the north-descending slope immediately below this strandline are interpreted as fault scarps offsetting a lacustrine abrasion platform. The faults offsetting the abrasion platform most likely join downward into and slip sympathetically with the Mormon Point turtleback fault, implying late Quaternary slip on this low-angle normal fault. Our geomorphic reinterpretation implies that the OIS-5e/6 lake receded rapidly enough not to cut strandlines and was ~90 m deep. Consistent with independent core studies of the salt pan, no evidence of OIS-2 lake strandlines was found at Mormon Point, which indicates that the maximum elevation of the OIS-2 lake surface was -30 m msl. Thus, as measured by pluvial lake depth, the OIS-2 effective precipitation was significantly less than during OIS-5e/6, a finding that is more consistent with other studies in the region. The changed geomorphic context indicates that previous surface exposure dates on fault scarps and benches at Mormon Point are uninterpretable with respect to lake history. ?? 2002 University of Washington.

Quantifying geomorphic change at ephemeral stream restoration sites using a coupled-model approach

USGS Publications Warehouse

Norman, Laura M.; Sankey, Joel B.; Dean, David; Caster, Joshua J.; DeLong, Stephen B.; Henderson-DeLong, Whitney; Pelletier, Jon D.

2017-01-01

Rock-detention structures are used as restoration treatments to engineer ephemeral stream channels of southeast Arizona, USA, to reduce streamflow velocity, limit erosion, retain sediment, and promote surface-water infiltration. Structures are intended to aggrade incised stream channels, yet little quantified evidence of efficacy is available. The goal of this 3-year study was to characterize the geomorphic impacts of rock-detention structures used as a restoration strategy and develop a methodology to predict the associated changes. We studied reaches of two ephemeral streams with different watershed management histories: one where thousands of loose-rock check dams were installed 30 years prior to our study, and one with structures constructed at the beginning of our study. The methods used included runoff, sediment transport, and geomorphic modelling and repeat terrestrial laser scanner (TLS) surveys to map landscape change. Where discharge data were not available, event-based runoff was estimated using KINEROS2, a one-dimensional kinematic-wave runoff and erosion model. Discharge measurements and estimates were used as input to a two-dimensional unsteady flow-and-sedimentation model (Nays2DH) that combined a gridded flow, transport, and bed and bank simulation with geomorphic change. Through comparison of consecutive DEMs, the potential to substitute uncalibrated models to analyze stream restoration is introduced. We demonstrate a new approach to assess hydraulics and associated patterns of aggradation and degradation resulting from the construction of check-dams and other transverse structures. Notably, we find that stream restoration using rock-detention structures is effective across vastly different timescales.

Hyperspectral remote sensing exploration of carbonatite - an example from Epembe, Kunene region, Namibia

NASA Astrophysics Data System (ADS)

Zimmermann, Robert; Brandmeier, Melanie; Andreani, Louis; Gloaguen, Richard

2015-04-01

Remote sensing data can provide valuable information about ore deposits and their alteration zones at surface level. High spectral and spatial resolution of the data is essential for detailed mapping of mineral abundances and related structures. Carbonatites are well known for hosting economic enrichments in REE, Ta, Nb and P (Jones et al. 2013). These make them a preferential target for exploration for those critical elements. In this study we show how combining geomorphic, textural and spectral data improves classification result. We selected a site with a well-known occurrence in northern Namibia: the Epembe dyke. For analysis LANDSAT 8, SRTM and airborne hyperspectral (HyMap) data were chosen. The overlapping data allows a multi-scale and multi-resolution approach. Results from data analysis were validated during fieldwork in 2014. Data was corrected for atmospherical and geometrical effects. Image classification, mineral mapping and tectonic geomorphology allow a refinement of the geological map by lithological mapping in a second step. Detailed mineral abundance maps were computed using spectral unmixing techniques. These techniques are well suited to map abundances of carbonate minerals, but not to discriminate the carbonatite itself from surrounding rocks with similar spectral signatures. Thus, geometric indices were calculated using tectonic geomorphology and textures. For this purpose the TecDEM-toolbox (SHAHZAD & GLOAGUEN 2011) was applied to the SRTM-data for geomorphic analysis. Textural indices (e.g. uniformity, entropy, angular second moment) were derived from HyMap and SRTM by a grey-level co-occurrence matrix (CLAUSI 2002). The carbonatite in the study area is ridge-forming and shows a narrow linear feature in the textural bands. Spectral and geometric information were combined using kohonen Self-Organizing Maps (SOM) for unsupervised clustering. The resulting class spectra were visually compared and interpreted. Classes with similar signatures were merged according to geological context. The major conclusions are: 1. Carbonate minerals can be mapped using spectral unmixing techniques. 2. Carbonatites are associated with specific geometric pattern 3. The combination of spectral and geometric information improves classification result and reduces misclassification. References Clausi, D. A. (2002): An analysis of co-occurrence texture statistics as a function of grey-level quantization. - Canadian Journal of Remote Sensing, 28 (1), 45-62 Jones, A. P., Genge, M. and Carmody, L (2013): Carbonate Melts and Carbonatites. - Reviews in Mineralogy & Geochemistry, 75, 289-322 Shahzad, F. & Gloaguen, R. (2011): TecDEM: A MATLAB based toolbox for tectonic geomorphology, Part 2: Surface dynamics and basin analysis. - Computers and Geosciences, 37 (2), 261-271

Surficial geologic map of the Heath-Northfield-Southwick-Hampden 24-quadrangle area in the Connecticut Valley region, west-central Massachusetts

USGS Publications Warehouse

Stone, Janet R.; DiGiacomo-Cohen, Mary L.

2010-01-01

The surficial geologic map layer shows the distribution of nonlithified earth materials at land surface in an area of 24 7.5-minute quadrangles (1,238 mi2 total) in west-central Massachusetts. Across Massachusetts, these materials range from a few feet to more than 500 ft in thickness. They overlie bedrock, which crops out in upland hills and as resistant ledges in valley areas. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic features, stratigraphic relationships, and age. Surficial materials also are known in engineering classifications as unconsolidated soils, which include coarse-grained soils, fine-grained soils, and organic fine-grained soils. Surficial materials underlie and are the parent materials of modern pedogenic soils, which have developed in them at the land surface. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for assessing water resources, construction aggregate resources, and earth-surface hazards, and for making land-use decisions. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text, quadrangle maps at 1:24,000 scale (PDF files), GIS data layers (ArcGIS shapefiles), metadata for the GIS layers, scanned topographic base maps (TIF), and a readme.txt file.

Surficial geologic map of the Norton-Manomet-Westport-Sconticut Neck 23-quadrangle area in southeast Massachusetts

USGS Publications Warehouse

Stone, Byron D.; Stone, Janet R.; DiGiacomo-Cohen, Mary L.; Kincare, Kevin A.

2012-01-01

The surficial geologic map shows the distribution of nonlithified earth materials at land surface in an area of 23 7.5-minute quadrangles (919 mi2 total) in southeastern Massachusetts. Across Massachusetts, these materials range from a few feet to more than 500 ft in thickness. They overlie bedrock, which crops out in upland hills and as resistant ledges in valley areas. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic features, stratigraphic relationships, and age. Surficial materials also are known in engineering classifications as unconsolidated soils, which include coarse-grained soils, fine-grained soils, and organic fine-grained soils. Surficial materials underlie and are the parent materials of modern pedogenic soils, which have developed in them at the land surface. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for assessing water resources, construction aggregate resources, and earth-surface hazards, and for making land-use decisions. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text (PDF), quadrangle maps at 1:24,000 scale (PDF files), GIS data layers (ArcGIS shapefiles), metadata for the GIS layers, scanned topographic base maps (TIF), and a readme.txt file.

Surficial geologic map of the Mount Grace-Ashburnham-Monson-Webster 24-quadrangle area in central Massachusetts

USGS Publications Warehouse

Stone, Janet R.

2013-01-01

The surficial geologic map shows the distribution of nonlithified earth materials at land surface in an area of 24 7.5-minute quadrangles (1,238 mi2 total) in central Massachusetts. Across Massachusetts, these materials range from a few feet to more than 500 ft in thickness. They overlie bedrock, which crops out in upland hills and as resistant ledges in valley areas. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic features, stratigraphic relationships, and age. Surficial materials also are known in engineering classifications as unconsolidated soils, which include coarse-grained soils, fine-grained soils, and organic fine-grained soils. Surficial materials underlie and are the parent materials of modern pedogenic soils, which have developed in them at the land surface. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for assessing water resources, construction-aggregate resources, and earth-surface hazards, and for making land-use decisions. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This report includes explanatory text (PDF), quadrangle maps at 1:24,000 scale (PDF files), GIS data layers (ArcGIS shapefiles), metadata for the GIS layers, scanned topographic base maps (TIF), and a readme.txt file.

Commercial vs professional UAVs for mapping

NASA Astrophysics Data System (ADS)

Nikolakopoulos, Konstantinos G.; Koukouvelas, Ioannis

2017-09-01

The continuous advancements in the technology behind Unmanned Aerial Vehicles (UAVs), in accordance with the consecutive decrease to their cost and the availability of photogrammetric software, make the use of UAVs an excellent tool for large scale mapping. In addition with the use of UAVs, the problems of increased costs, time consumption and the possible terrain accessibility problems, are significantly reduced. However, despite the growing number of UAV applications there has been a little quantitative assessment of UAV performance and of the quality of the derived products (orthophotos and Digital Surface Models). Here, we present results from field experiments designed to evaluate the accuracy of photogrammetrically-derived digital surface models (DSM) developed from imagery acquired with onboard digital cameras. We also show the comparison of the high resolution vs moderate resolution imagery for largescale geomorphic mapping. The acquired data analyzed in this study comes from a small commercial and a professional UAV. The test area was mapped using the same photogrammetric grid by the two UAVs. 3D models, DSMs and orthophotos were created using special software. Those products were compared to in situ survey measurements and the results are presented in this paper.

Development of Envelope Curves for Predicting Void Dimensions from Overturned Trees

DTIC Science & Technology

2014-07-01

transport due to tree root throw: integrating tree population dynamics, wildfire, and geomorphic response (Gallaway et al. 2009...Johnson. 2009. Sediment transport due to tree root throw: Integrating tree population dynamics, wildfire and geomorphic response. Earth Surface Processes...environment, but not vegetation (Peterson and Leach 2008) ............................................................ 17 4.7 Pedologic and geomorphic impacts

Geologic/geomorphic map of the Galindo Quadrangle (V-40), Venus

USGS Publications Warehouse

Chapman, Mary G.

2000-01-01

The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the venusian atmosphere on October 12, 1994. Magellan had the objectives of (1) improving knowledge of the geologic processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving knowledge of the geophysics of Venus by analysis of venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three datasets: synthetic aperture radar (SAR) images of the surface, passive microwave thermal emission observations, and measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging and altimetric and radiometric mapping of the venusian surface were done in mission cycles 1, 2, and 3, from September 1990 until September 1992. Ninety-eight percent of the surface was mapped with radar resolution of approximately 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution; these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal-receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied from about 20° to 45°. High-resolution Doppler tracking of the spacecraft was done from September 1992 through October 1994 (mission cycles 4, 5, 6). High-resolution gravity observations from about 950 orbits were obtained between September 1992 and May 1993, while Magellan was in an elliptical orbit with a periapsis near 175 kilometers and an apoapsis near 8,000 kilometers. Observations from an additional 1,500 orbits were obtained following orbitcircularization in mid-1993. These data exist as a 75° by 75° harmonic field.

Geomorphic Classification and Assessment of Channel Dynamics in the Missouri National Recreational River, South Dakota and Nebraska

USGS Publications Warehouse

Elliott, Caroline M.; Jacobson, Robert B.

2006-01-01

A multiscale geomorphic classification was established for the 39-mile, 59-mile, and adjacent segments of the Missouri National Recreational River administered by the National Park Service in South Dakota and Nebraska. The objective of the classification was to define naturally occurring clusters of geomorphic characteristics that would be indicative of discrete sets of geomorphic processes, with the intent that such a classification would be useful in river-management and rehabilitation decisions. The statistical classification was based on geomorphic characteristics of the river collected from 1999 orthophotography and the persistence of classified units was evaluated by comparison with similar datasets for 2003 and 2004 and by evaluating variation of bank erosion rates by geomorphic class. Changes in channel location and form were also explored using imagery and maps from 1993-2004, 1941 and 1894. The multivariate classification identified a hierarchy of naturally occurring clusters of reach-scale geomorphic characteristics. The simplest level of the hierarchy divides the river from segments into discrete reaches characterized by single and multithread channels and additional hierarchical levels established 4-part and 10-part classifications. The classification system presents a physical framework that can be applied to prioritization and design of bank stabilization projects, design of habitat rehabilitation projects, and stratification of monitoring and assessment sampling programs.

Study of ice-related flow features around Tanaica Montes, Mars: Implications for late amazonian debris-covered glaciation

NASA Astrophysics Data System (ADS)

Sinha, Rishitosh K.; Vijayan, S.; Bharti, Rajiv R.

2017-11-01

Lobate debris aprons (LDA) and lineated valley fill (LVF) have been broadly recognized in the mid-latitudes of Mars and their subsequent analyses using data from the SHAllow RADar (SHARAD) instrument has suggested evidence for contemporary ice preserved beneath these features. In this study, we conduct detailed characterization of newly identified LDA flow units within the Tanaica Montes region (39.55˚ N, 269.17˚ E) of Mars to assess and understand the similarities in their emplacement with respect to LDA flow units mapped in other regions of Mars. We utilize the Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) images and SHAllow RADar (SHARAD) datasets for geomorphic and subsurface analysis and Mars Global Surveyor (MGS) Mars Orbiter Laser Altimeter (MOLA) point tracks for topographic analysis. Geomorphic observation of LDA flow units surrounding the montes flanks and massif walls reveal integrated pattern of convergence and divergence and evidence of bending and deflection within the flow lines that resulted in concentric, loop-like flow patterns in the downslope. Brain-terrain texture and craters with varying morphological characteristics (ring-mold type) is suggestive that LDAs may be similar to ice-rich, debris-covered glaciers. MOLA point track based convex-up topographic profiles of LDAs suggest that their thickness vary in the range of ∼100-200 m in both the northwestern and southeastern portions of study region. Further, the slope values of mapped LDA surfaces within the study region are within ∼0.1˚-4˚. The extent of mapped LDAs within the study region is such that some of the low elevation (∼0.8-1.3 km) portions of montes flanks are surrounded by relatively less extent (up to ∼0.5-0.8 km) of LDA flow units. Geomorphic and topographic evidence for flow units that appear to be superposed on the main LDA body collectively suggest the possibility of episodic glacial activity in the region. Furthermore, based on the alignment of subsurface reflectors with the surrounding plains when a permittivity of ice (3.2) is assumed and the radargram is depth-corrected, we infer that some of the portions of LDA flow units have preserved ice in their subsurface up to ∼300-500 m depth. Crater size frequency distribution of craters counted on LDA surface indicates that the best-fit age is ∼110 Ma. In addition, the LDA surfaces exhibit different best-fit ages for different types of crater morphologies (bowl-shaped, ring-mold and infilled craters) included in the crater count statistics. Together, these observations and the interpretations suggest that most, if not all, of the LDAs in the study region are like classical LDAs mapped in other regions of Mars (e.g. along the mid-latitude dichotomy boundary and eastern Hellas region). These results indicate that a widespread accumulation and preservation of ice has occurred during the Late Amazonian as suggested in previous studies.

Geomorphic Mapping of Lava Flows on Mars, Earth, and Mercury

NASA Astrophysics Data System (ADS)

Golder, K. B.; Burr, D. M.

2018-06-01

To advance understanding of flood basalts, we have mapped lava flows on three planets, Mars, Earth, and Mercury, as part of three projects. The common purpose of each project is to investigate potential magma sources and/or emplacement conditions.

Synergies between geomorphic hazard and risk and sediment cascade research fields: exploiting geomorphic processes' susceptibility analyses to derive potential sediment sources in the Oltet, river catchment, southern Romania

NASA Astrophysics Data System (ADS)

Jurchescu, Marta-Cristina

2015-04-01

Identifying sediment sources and sediment availability represents a major problem and one of the first concerns in the field of sediment cascade. This paper addresses the on-site effects associated with sediment transfer, investigating the degree to which studies pertaining to the field of geomorphic hazard and risk research could be exploited in sediment budget estimations. More precisely, the paper investigates whether results obtained in assessing susceptibility to various geomorphic processes (landslides, soil erosion, gully erosion) could be transferred to the study of sediment sources within a basin. The study area is a medium-sized catchment (> 2400 km2) in southern Romania encompassing four different geomorphic units (mountains, hills, piedmont and plain). The region is highly affected by a wide range of geomorphic processes which supply sediments to the drainage network. The presence of a reservoir at the river outlet emphasizes the importance of estimating sediment budgets. The susceptibility analyses are conducted separately for each type of the considered processes in a top-down framework, i.e. at two different scales, using scale-adapted methods and validation techniques in each case, as widely-recognized in the hazard and risk research literature. The analyses start at a regional scale, which has in view the entire catchment, using readily available data on conditioning factors. In a second step, the suceptibility analyses are carried out at a medium scale for selected hotspot-compartments of the catchment. In order to appraise the extent to which susceptibility results are relevant in interpreting sediment sources at catchment scale, scale-induced differences are analysed in the case of each process. Based on the amount of uncertainty revealed by each regional-scale analysis in comparison to the medium-scale ones, decisions are made on whether the first are acceptable to the aim of identifying potential sediment source areas or if they should be refined using more precise methods and input data. The three final basin-wide susceptibility maps are eventually coverted, on a threshold basis, to maps showing the potential areas of sediment production by landslides, soil erosion and gully erosion respectively. These are then combined into one single map of potential sediment sources. The susceptibility assessments indicate that the basin compartments most prone to landslides and soil erosion correspond to the Subcarpathian hills, while the one most threatened by gully erosion corresponds to the piedmont relief. The final map of potential sediment sources shows that approximately 34% of the study catchment is occupied by areas potentially generating sediment through landslides and gully erosion, extending over most of the high piedmont and Subcarpathian hills. The results prove that there is an important link between the two research fields, i.e. geomorphic hazard and risk and sediment cascade, by allowing the transfer of knowledge from geomorphic processes' susceptibility analyses to the estimation of potential sediment sources within catchments. The synergy between the two fields raises further challenges to be tackled in future (e.g. how to derive sediment transfer rates from quantitative hazard estimates).

Estimating Earthquake Magnitude from the Kentucky Bend Scarp in the New Madrid Seismic Zone Using Field Geomorphic Mapping and High-Resolution LiDAR Topography

NASA Astrophysics Data System (ADS)

Kelson, K. I.; Kirkendall, W. G.

2014-12-01

Recent suggestions that the 1811-1812 earthquakes in the New Madrid Seismic Zone (NMSZ) ranged from M6.8-7.0 versus M8.0 have implications for seismic hazard estimation in the central US. We more accurately identify the location of the NW-striking, NE-facing Kentucky Bend scarp along the northern Reelfoot fault, which is spatially associated with the Lake County uplift, contemporary seismicity, and changes in the Mississippi River from the February 1812 earthquake. We use 1m-resolution LiDAR hillshades and slope surfaces, aerial photography, soil surveys, and field geomorphic mapping to estimate the location, pattern, and amount of late Holocene coseismic surface deformation. We define eight late Holocene to historic fluvial deposits, and delineate younger alluvia that are progressively inset into older deposits on the upthrown, western side of the fault. Some younger, clayey deposits indicate past ponding against the scarp, perhaps following surface deformational events. The Reelfoot fault is represented by sinuous breaks-in-slope cutting across these fluvial deposits, locally coinciding with shallow faults identified via seismic reflection data (Woolery et al., 1999). The deformation pattern is consistent with NE-directed reverse faulting along single or multiple SW-dipping fault planes, and the complex pattern of fluvial deposition appears partially controlled by intermittent uplift. Six localities contain scarps across correlative deposits and allow evaluation of cumulative surface deformation from LiDAR-derived topographic profiles. Displacements range from 3.4±0.2 m, to 2.2±0.2 m, 1.4±0.3 m, and 0.6±0.1 m across four progressively younger surfaces. The spatial distribution of the profiles argues against the differences being a result of along-strike uplift variability. We attribute the lesser displacements of progressively younger deposits to recurrent surface deformation, but do not yet interpret these initial data with respect to possible earthquake magnitudes. Additional efforts hopefully will address shallow subsurface evidence of single- or multiple-deformational events at selected localities.

Tectonic geomorphology of the Andes with SIR-A and SIR-B

NASA Technical Reports Server (NTRS)

Bloom, Arthur L.; Fielding, Eric J.

1986-01-01

Data takes from SIR-A and SIR-B (Shuttle Imaging Radar) crossed all of the principal geomorphic provinces of the central Andes between 17 and 34 S latitude. In conjunction with Thematic Mapping images and photographs from hand-held cameras as well as from the Large Format Camera that was flown with SIR-B, the radar images give an excellent sampling of Andean geomorphology. In particular, the radar images show new details of volcanic rocks and landforms of late Cenozoic age in the Puna, and the exhumed surfaces of tilted blocks of Precambrian crystalline basement in the Sierras Pampeanas.

Near-shore Evaluation of Holocene Faulting and Earthquake Hazard in the New York City Metropolitan Region

NASA Astrophysics Data System (ADS)

Cormier, M. H.; King, J. W.; Seeber, L.; Heil, C. W., Jr.; Caccioppoli, B.

2016-12-01

During its relatively short historic period, the Atlantic Seaboard of North America has experienced a few M6+ earthquakes. These events raise the specter of a similar earthquake occurring anywhere along the eastern seaboard, including in the greater New York City (NYC) metropolitan area. Indeed, the NYC Seismic Zone is one of several concentrations of earthquake activity that stand out in the field of epicenters over eastern North America. Various lines of evidence point to a maximum magnitude in the M7 range for metropolitan NYC - a dramatic scenario that is counterbalanced by the low probability of such an event. Several faults mapped near NYC strike NW, sub-normal to the NE-striking structural trends of the Appalachians, and all earthquake sequences with well-established fault sources in the NYC seismic zone originate from NW-striking faults. With funding from the USGS Earthquake Hazard Program, we recently (July 2016) collected 85 km of high-resolution sub-bottom (CHIRP) profiles along the north shore of western Long Island Sound, immediately adjacent to metropolitan NYC. This survey area is characterized by a smooth, 15.5 kyr-old erosional surface and overlying strata with small original relief. CHIRP sonar profiles of these reflectors are expected to resolve fault or fold-related vertical relief (if present) greater than 50 cm. They would also resolve horizontal fault displacements with similar resolution, as may be expressed by offsets of either sedimentary or geomorphic features. No sedimentary cover on the land portion of the metro area offers such ideal reference surfaces, which are continuous in both time and space. Seismic profiles have a spacing of 200 m and have been acquired mostly perpendicular to the NW-striking faults mapped on land. These new data will be analyzed systematically for all resolvable features and then interpreted, distinguishing sedimentary, geomorphic, and tectonic features. The absence of evidence of post-glacial tectonic deformation would be a reliable negative result with implications regarding the lateral dimensions and southeastward continuity of the brittle faults mapped on land, and their potential for generation of large earthquakes with surface ruptures.

The geomorphic legacy of water and erosion control structures in a semiarid rangeland watershed

USGS Publications Warehouse

Nichols, Mary H.; Magirl, Christopher S.; Sayre, N.F.; Shaw, Jeremy R.

2018-01-01

Control over water supply and distribution is critical for agriculture in drylands where manipulating surface runoff often serves the dual purpose of erosion control. However, little is known of the geomorphic impacts and legacy effects of rangeland water manipulation infrastructure, especially if not maintained. This study investigated the geomorphic impacts of structures such as earthen berms, water control gates, and stock tanks, in a semiarid rangeland in the southwestern USA that is responding to both regional channel incision that was initiated over a century ago, and a more recent land use change that involved cattle removal and abandonment of structures. The functional condition of remnant structures was inventoried, mapped, and assessed using aerial imagery and lidar data. Headcut initiation, scour, and channel incision associated with compromised lateral channel berms, concrete water control structures, floodplain water spreader berms, and stock tanks were identified as threats to floodplains and associated habitat. Almost half of 27 identified lateral channel berms (48%) have been breached and 15% have experienced lateral scour; 18% of 218 shorter water spreader berms have been breached and 17% have experienced lateral scour. A relatively small number of 117 stock tanks (6%) are identified as structurally compromised based on analysis of aerial imagery, although many currently do not provide consistent water supplies. In some cases, the onset of localized disturbance is recent enough that opportunities for mitigation can be identified to alter the potentially damaging erosion trajectories that are ultimately driven by regional geomorphic instability. Understanding the effects of prior land use and remnant structures on channel and floodplain morphologic condition is critical because both current land management and future land use options are constrained by inherited land use legacy effects.

Geomorphic and hydraulic assessment of the Bear River in and near Evanston, Wyoming

USGS Publications Warehouse

Smith, M.E.; Maderak, M.L.

1993-01-01

Geomorphic and hydraulic characteristics of the Bear River in and near Evanston, Wyoming, were assessed to assist planners in stabilizing the river channel. Present-day channel instability is the result of both human-made and natural factors. The primary factor is channelization of the river in Evanston, where several meander loops were cut off artificially during early development of the city. Other contributing factors include channel-width constrictions, bank stabilization, isolated bend cutoffs upstream from the city, and flooding in 1983 and 1984. A geomorphic analysis of bankfull-channel pattern, based on four aerial photographs taken during 1946-86, quantified geomorphic properties (reach sinuosity, bend sinuosity, bend radius of curvature, and bed length) that are characteristic of the study reach. The reach sinuosity of reach 2 (the channelized reach in Evanston) was 1.18 in 1986 and remained about the same throughout the period (1946-86). The reach sinuosity of reach 2 prior to channelization was substantially larger, about 2.3 as determined from maps prepared before 1946. Hydraulic analysis of the present-day channel (surveyed 1981-87) using a one-dimensional water-surface-profile computer model identified a bankfull discharge for the study reach of 3,600 cu ft/sec. A comparison of bankfull hydraulic properties for reaches 1, 2, and 3 indicated that the effects in reach 2 of channelization and channel-width constriction--increased slope, faster velocities, and greater hydraulic radii. The present-day channel slope in reach 2 is 0.00518 ft/ft, whereas a more stable slope would be between 0.00431 ft/ft (present-day slope in reach 1) and 0.00486 ft/ft (present-day slope in reach 3).

Late glacial and Holocene history of the Greenland Ice Sheet margin, Nunatarssuaq, Northwestern Greenland

NASA Astrophysics Data System (ADS)

Farnsworth, L. B.; Kelly, M. A.; Axford, Y.; Bromley, G. R.; Osterberg, E. C.; Howley, J. A.; Zimmerman, S. R. H.; Jackson, M. S.; Lasher, G. E.; McFarlin, J. M.

2015-12-01

Defining the late glacial and Holocene fluctuations of the Greenland Ice Sheet (GrIS) margin, particularly during periods that were as warm or warmer than present, provides a longer-term perspective on present ice margin fluctuations and informs how the GrIS may respond to future climate conditions. We focus on mapping and dating past GrIS extents in the Nunatarssuaq region of northwestern Greenland. During the summer of 2014, we conducted geomorphic mapping and collected rock samples for 10Be surface exposure dating as well as subfossil plant samples for 14C dating. We also obtained sediment cores from an ice-proximal lake. Preliminary 10Be ages of boulders deposited during deglaciation of the GrIS subsequent to the Last Glacial Maximum range from ~30-15 ka. The apparently older ages of some samples indicate the presence of 10Be inherited from prior periods of exposure. These ages suggest deglaciation occurred by ~15 ka however further data are needed to test this hypothesis. Subfossil plants exposed at the GrIS margin on shear planes date to ~ 4.6-4.8 cal. ka BP and indicate less extensive ice during middle Holocene time. Additional radiocarbon ages from in situ subfossil plants on a nunatak date to ~3.1 cal. ka BP. Geomorphic mapping of glacial landforms near Nordsø, a large proglacial lake, including grounding lines, moraines, paleo-shorelines, and deltas, indicate the existence of a higher lake level that resulted from a more extensive GrIS margin likely during Holocene time. A fresh drift limit, characterized by unweathered, lichen-free clasts approximately 30-50 m distal to the modern GrIS margin, is estimated to be late Holocene in age. 10Be dating of samples from these geomorphic features is in progress. Radiocarbon ages of subfossil plants exposed by recent retreat of the GrIS margin suggest that the GrIS was at or behind its present location at AD ~1650-1800 and ~1816-1889. Results thus far indicate that the GrIS margin in northwestern Greenland responded sensitively to Holocene climate changes. Ongoing research will improve the chronological constraints on these fluctuations.

Constructing a sequence of palaeoDEMs to obtain erosion rates in a drainage basin.N

NASA Astrophysics Data System (ADS)

Castelltort, F. Xavier; Carles Balasch, J.; Cirés, Jordi; Colombo, Ferran

2017-04-01

DEMs made in a present-day drainage basin, considering it as a geomorphic unit, represent the end result of a landscape evolution. This process has had to follow a model of erosion. Trying to establish a conceptual erosion model in landscape evolution represents the first difficulty in constructing a sequence of palaeoDEMs. But if one is able to do it, the result will be easier and believable. The next step to do is to make a catalogue of base level types present in the drainage basin. The list has to include elements with determinate position and elevation (x, y, z) from the centre of the basin until hillslopes. A list of base level types may contain fluvial terrace remnants, erosive surfaces, palaeosols, alluvial covers of glacis, alluvial fans, rockfalls, landslides and scree zones. It is very important to know the spatial and temporal relations between the elements of the list, even if they are disconnected by erosion processes. Relative chronologies have to be set for all elements of the catalogue, and as far as possible absolute chronologies. To do it,it is essential to have established first the spatial relations between them, including those elements that are gone. Moreover, it is also essential to have adapted all the elements to the conceptual erosion model proposed. In this step, it has to be kept in mind that erosion rates can be very different in determinate areas within the same geomorphic unit. Erosion processes are focused in specific zones while other areas are maintained in stability. A good technique to construct a palaeoDEM is to start making, by hand, a map of contour lines. At this point, it is valuable to use the elements' catalogue. The use of those elements belonging to the same palaeosurface will result in a map. Several maps can be obtained from a catalogue. Contour maps can be gridded into a 3D surface by means of a specific application and a set of surfaces will be obtained. Algebraic operations can be done with palaeoDEMs obtaining positive or negative volumes corresponding to processes of erosion or aggradation. A case study of the application of palaeoDEMs is presented in the process of homoclinal shifting that is the origin of the strike valley of La Plana de Vic in the NE of Iberian Peninsula.

From Hype to an Operational Tool: Efforts to Establish a Long-Term Monitoring Protocol of Alluvial Sandbars using `Structure-from-Motion' Photogrammetry

NASA Astrophysics Data System (ADS)

Rossi, R.; Buscombe, D.; Grams, P. E.; Schmidt, J. C.; Wheaton, J. M.

2016-12-01

Despite recent advances in the use of `Structure-from-Motion' (SfM) photogrammetry to accurately map landforms, its utility for reliably detecting and monitoring geomorphic change from repeat surveys remains underexplored in fluvial environments. It is unclear how the combination of various image acquisition platforms and techniques, survey scales, vegetation cover, and terrain complexities translate into accuracy and precision metrics for SfM-based construction of digital elevation models (DEMs) of fluvial landforms. Although unmanned aerial vehicles offer the potential to rapidly image large areas, they can be relatively costly, require skilled operators, are vulnerable in adverse weather conditions, and often rely on GPS-positioning to improve their stability. This research details image acquisition techniques for an underrepresented SfM platform: the pole-mounted camera. We highlight image acquisition and post-processing limitations of the SfM method for alluvial sandbars (10s to 100s m2) located in Marble and Grand Canyons in a remote, fluvial landscape with limited field access, strong light gradients, highly variable surface texture and limited ground control. We recommend a pole-based SfM protocol and evaluate it by comparing SfM-derived DEMs against concurrent, total station surveys. Error models of the sandbar surfaces are developed for a variety of surface characteristics (e.g., bare sand, steep slopes, and areas of shadow). The Geomorphic Change Detection (GCD) Software is used to compare SfM DEMs from before and after the 2014 high flow release from Glen Canyon Dam. Complementing existing total-station based sandbar surveys with potentially more efficient and cost-effective SfM methods will contribute to the understanding of morphodynamic responses of sandbars to high flow releases from Glen Canyon Dam. In addition, the development and implementation of a SfM-based operational method for monitoring geomorphic change will provide a methodological foundation for extending the approach to other fluvial environments.

From Hype to an Operational Tool: Efforts to Establish a Long-Term Monitoring Protocol of Alluvial Sandbars using 'Structure-from-Motion' Photogrammetry

NASA Astrophysics Data System (ADS)

Rossi, R.; Buscombe, D.; Grams, P. E.; Wheaton, J. M.

2015-12-01

Despite recent advances in the use of 'Structure-from-Motion' (SfM) photogrammetry to accurately map landforms, its utility for reliably detecting and monitoring geomorphic change from repeat surveys remains underexplored in fluvial environments. It is unclear how the combination of various image acquisition platforms and techniques, survey scales, vegetation cover, and terrain complexities translate into accuracy and precision metrics for SfM-based construction of digital elevation models (DEMs) of fluvial landforms. Although unmanned aerial vehicles offer the potential to rapidly image large areas, they can be relatively costly, require skilled operators, are vulnerable in adverse weather conditions, and often rely on GPS-positioning to improve their stability. This research details image acquisition techniques for an underrepresented SfM platform: the pole-mounted camera. We highlight image acquisition and post-processing limitations of the SfM method for alluvial sandbars (10s to 100s m2) located in Marble and Grand Canyons in a remote, fluvial landscape with limited field access, strong light gradients, highly variable surface texture and limited ground control. We recommend a pole-based SfM protocol and evaluate it by comparing SfM-derived DEMs against concurrent, total station surveys and TLS derived DEMs. Error models of the sandbar surfaces are developed for a variety of surface characteristics (e.g., bare sand, steep slopes, and areas of shadow). The Geomorphic Change Detection (GCD) Software is used to compare SfM DEMs from before and after the 2014 high flow release from Glen Canyon Dam. Complementing existing total-station based sandbar surveys with potentially more efficient and cost-effective SfM methods will contribute to the understanding of morphodynamic responses of sandbars to high flow releases from Glen Canyon Dam. In addition, the development and implementation of a SfM-based operational protocol for monitoring geomorphic change will provide a methodological foundation for extending the approach to other fluvial environments.

Scaling Considerations Related to Interactions of Hydrologics, Pedologic and Geomorphic Processes

EPA Science Inventory

Hydrologic, pedologic, and geomorphic processes are strongly interrelated and affected by scale. These interactions exert important controls on runoff generation, preferential flow, contaminant transport, surface erosion, and mass wasting. Measurement of hydraulic conductivity (K...

High Resolution Mapping and Interpretation of Channel and Floodplain Topography With a Narrow-Beam Terrestrial-Aquatic Lidar

NASA Astrophysics Data System (ADS)

McKean, J.; Isaak, D.; Tonina, D.; Wright, W.; Kinzel, P.

2007-12-01

Basic description of channel and floodplain topography remains a fundamental challenge for modeling flow and sediment transport or even simply mapping habitat. Standard field wading and boat surveys of stream topography are limited by costs and logistics to relatively small sample reaches and floodplain maps are seldom well- integrated with channel bathymetry. We used the NASA Experimental Advanced Airborne Research Lidar (EAARL) to map channel and floodplain topography and investigate geomorphic controls on physical habitat in two diverse channels in the watershed of the Middle Fork Salmon River, Idaho. Bear Valley Creek is a small low-gradient gravel-bed stream flowing across an unconfined valley filled with glacial outwash materials. A hierarchy of nested geomorphic features is evident in this channel with the broadest fluvial domains a legacy of ~15,000 years of post-glacial valley evolution. Contemporary hydraulics operate on this broad template and control two smaller scales of pool-riffle morphology. Salmon spawning patterns closely reflect these nested physical domains, demonstrating how geomorphic history can influence modern distributions of aquatic habitat and organisms. In contrast, Big Creek is a higher-gradient stream predominately confined by steep side slopes in a deep valley. Here, the distribution of geomorphic domains and physical habitat is controlled by modern erosion processes and rock quality. Tributaries and valley walls contribute coarse debris, up to large boulders, to the channel, resulting in very rough and poorly organized bed topography. Tributary fans also function as local grade control with sediment deposition in lower-gradient reaches upstream of fans. A GIS toolkit is under development to extract at-a-station channel metrics from EAARL data, including for example, cross section and longitudinal profile characteristics. A new investigation has also begun to further investigate the quality of EAARL data. This study will explore the question of how well we must describe channel topography to adequately: i) map the spatial distribution of physical habitat for management purposes and in support of organism population growth models, and ii) define boundary conditions for flow and sediment transport predictions using the USGS model MD SWMS.

Geomorphic degradations on the surface of venus: an analysis of venera 9 and venera 10 data.

PubMed

Florensky, C P; Ronca, L B; Basilevsky, A T

1977-05-20

On the basis of the physical and chemical measurements made on the surface of Venus and transmitted back to Earth by the Soviet automatic landers Venera 9 and Venera 10, a geomorphically inactive environment should be expected. An analysis of the television photographs reveals, however, that at least two processes of degradation occur. One operates on a scale of decimeters to meters and is responsible for the fracturing of a layered source rock and the subsequent downslope movement of the fragments. Mass-wasting, perhaps activated by venusian quakes or by unknown geological processes, is likely to be the agent. Another geomorphic degradation process occurs on the scale of a centimeter or less and is responsible for the rounding of edges and the pitting of rock surfaces. The agents of this process are not known, but atmospheric action, perhaps in connection with volcanic episodes, may be the cause. From a geomorphic point of view, the landscape of the Venera 9 landing site can be considered young and that of the Venera 10 landing site, mature.

Late Quaternary faulting in the Cabo San Lucas-La Paz Region, Baja California

NASA Astrophysics Data System (ADS)

Busch, M.; Arrowsmith, J. R.; Umhoefer, P. J.; Gutiérrez, G. M.; Toke, N.; Brothers, D.; Dimaggio, E.; Maloney, S.; Zielke, O.; Buchanan, B.

2006-12-01

While Baja California drifts, active deformation on and just offshore indicates that spreading is not completely localized to the rift axis in the Gulf of California. Using on and offshore data, we characterize normal faulting- related deformation in the Cabo San Lucas-La Paz area. We mapped sections of the north trending faults in a 150 km long left-stepping fault array. Starting in the south, the San Jose del Cabo fault (east dipping) bounds the ~2 km high Sierra La Laguna. It is >70 km long with well defined 1-10 meter fault scarps cutting the youngest late Quaternary geomorphic surfaces. Our preliminary mapping along the north central section exhibits extensive late Quaternary terraces with riser heights of tens of meters above Holocene terraces. The San Jose del Cabo fault trace becomes diffuse and terminates in the area of Los Barriles. Moving northward, the fault system steps to the west, apparently transferring slip to the faults of San Juan de Los Planes and Saltito, which then step left again across the La Paz basin to the NNW trending Carrizal Fault. It has an on shore length of > 60 km. We produced a 25 km detailed strip map along the northern segment. It is embayed by convex east arcs several km long and 100 m deep. In the south, few-m-high scarps cut a pediment of thin Quaternary cover over tertiary volcanic rocks. The escarpment along the fault is hundreds of meters high and scarps 1-10 m high where it goes offshore in the north. Near Bonfil, a quarry cut exposes the fault zone. It comprises a 5-10 m wide bedrock shear zone with sheared tertiary volcanic units. On the footwall, the lower silty and sandy units have moderately well developed pedogenic carbonate, whereas the upper coarse gravel does not. These late Quaternary units appear to be faulted by one to three earthquakes. Finally, we mapped the Saltito fault zone NNE of La Paz. It is a NW trending structure with well developed 5- 10 meter high bedrock scarps defining its NW 5 km and slightly concave east with a 500 m left. Along all the fault zones studied, offset geomorphic surfaces indicate late Pleistocene to Holocene offset. These surfaces can be exploited to determine slip rates and produce a regional chronosequence to test for synchroneity of climatically modulated variations in sediment supply and transport capacity. In addition, a shallow marine geophysics and coring extends our mapping and provides important age control and improved stratigraphic assessment of fault activity.

­Chronology of the Last Termination of Tsagaan Gol-Potanin Glacier Valley, Altai Mountains, Mongolia using 10Be surface-exposure dating

NASA Astrophysics Data System (ADS)

Radue, M. J.; Putnam, A. E.; Strand, P.; Norris, N. R.

2017-12-01

The last termination ( 19-11 ka) marks the end of the last ice age and the transition to modern interglacial conditions. Increasing Northern Hemisphere summer insolation alone cannot account for the rapid global warming during the termination and the mechanisms that triggered the dramatic deglaciation are unresolved. Various hypotheses for deglacial warming include an increase in atmospheric CO­2, changes in ocean circulation, shifting wind belts, and water vapor. Here, we investigate the last termination in the Mongolian Altai (49°N, 88°E), a mountain range in the heart of Asia, to constrain the nature of the termination in the center of Earth's largest continent. We present a 10Be surface-exposure chronology for a system of glacial landforms in the Tsagaan Gol- Potanin Glacier Valley. Our chronology is underpinned by detailed glacial geomorphic maps made using satellite and unmanned aerial vehicle (UAV) imagery. Based on our glacial reconstruction, we estimate changes in atmospheric temperature from the Last Glacial Maximum to the Late Holocene using snowline reconstruction techniques. Mongolia is an ideal location to document past climate because it is isolated from oceanic influences; therefore, our record should provide insight into the roles of local radiation forcing from changes in Earth's orbital configuration, greenhouse gases, and atmospheric heat transfer in Asian climate dynamics. With a high-resolution chronology and detailed glacial geomorphic maps of the Potanin-Tsagaan Gol Valley in the Mongolian Altai, we compare the timing of deglaciation in interior Asia with records of climate drivers, such as CO­2­­, to understand what caused this major global warming event.

Geomorphic Evolution and Slip rate Measurements of the Noushki Segment , Chaman Fault Zone, Pakistan

NASA Astrophysics Data System (ADS)

Abubakar, Y.; Khan, S. D.; Owen, L. A.; Khan, A.

2012-12-01

The Nushki segment of the Chaman fault system is unique in its nature as it records both the imprints of oblique convergence along the western Indian Plate boundary as well as the deformation along the Makran subduction zone. The left-lateral Chaman transform zone has evolved from a subduction zone along the Arabian-Eurasian collision complex to a strike-slip fault system since the collision of the Indian Plate with the Eurasia. The geodetically and geologically constrained displacement rates along the Chaman fault varies from about 18 mm/yr to about 35 mm/yr respectively throughout its total length of ~ 860 km. Two major hypothesis has been proposed by workers for these variations; i) Variations in rates of elastic strain accumulation along the plate boundary and, ii) strain partitioning along the plate boundary. Morphotectonic analysis is a very useful tool in investigations of spatial variations in tectonic activities both regionally and locally. This work uses morphotectonic analysis to investigate the degree of variations in active tectonic deformation, which can be directly related to elastic strain accumulation and other kinematics in the western boundary of the plate margin. Geomorphic mapping was carried out using remotely sensed data. ASTER and RADAR data were used in establishing Quaternary stratigraphy and measurement of geomorphic indices such as stream length gradient index, valley floor width to height ratio and, river/stream longitudinal profile within the study area. High resolution satellite images (e.g., IKONOS imagery) and 30m ASTER DEMs were employed to measure displacement recorded by landforms along individual strands of the fault. Results from geomorphic analysis shows three distinct levels of tectonic deformation. Areas showing high levels of tectonic deformation are characterized by displaced fan surfaces, deflected streams and beheaded streams. Terrestrial Cosmogenic nuclide surface exposure dating of the displaced landforms is being carried out to calculate slip-rates. Slip-rates estimation along this segment of this plate boundary will help in understanding of tectonic evolution of this plate boundary and seismic activity in the region.

The Use of a Geomorphometric Classification to Estimate Subsurface Heterogeneity in the Unconsolidated Sediments of Mountain Watersheds

NASA Astrophysics Data System (ADS)

Cairns, D.; Byrne, J. M.; Jiskoot, H.; McKenzie, J. M.; Johnson, D. L.

2013-12-01

Groundwater controls many aspects of water quantity and quality in mountain watersheds. Groundwater recharge and flow originating in mountain watersheds are often difficult to quantify due to challenges in the characterization of the local geology, as subsurface data are sparse and difficult to collect. Remote sensing data are more readily available and are beneficial for the characterization of watershed hydrodynamics. We present an automated geomorphometric model to identify the approximate spatial distribution of geomorphic features, and to segment each of these features based on relative hydrostratigraphic differences. A digital elevation model (DEM) dataset and predefined indices are used as inputs in a mountain watershed. The model uses periglacial, glacial, fluvial, slope evolution and lacustrine processes to identify regions that are subsequently delineated using morphometric principles. A 10 m cell size DEM from the headwaters of the St. Mary River watershed in Glacier National Park, Montana, was considered sufficient for this research. Morphometric parameters extracted from the DEM that were found to be useful for the calibration of the model were elevation, slope, flow direction, flow accumulation, and surface roughness. Algorithms were developed to utilize these parameters and delineate the distributions of bedrock outcrops, periglacial landscapes, alluvial channels, fans and outwash plains, glacial depositional features, talus slopes, and other mass wasted material. Theoretical differences in sedimentation and hydrofacies associated with each of the geomorphic features were used to segment the watershed into units reflecting similar hydrogeologic properties such as hydraulic conductivity and thickness. The results of the model were verified by comparing the distribution of geomorphic features with published geomorphic maps. Although agreement in semantics between datasets caused difficulties, a consensus yielded a comparison Dice Coefficient of 0.65. The results can be used to assist in groundwater model calibration, or to estimate spatial differences in near-surface groundwater behaviour. Verification of the geomorphometric model would be augmented by evaluating its success after use in the calibration of the groundwater simulation. These results may also be used directly in momentum-based equations to create a stochastic routing routine beneath the soil interface for a hydrometeorological model.

Alabama-Mississippi Coastal Classification Maps - Perdido Pass to Cat Island

USGS Publications Warehouse

Morton, Robert A.; Peterson, Russell L.

2005-01-01

The primary purpose of the USGS National Assessment of Coastal Change Project is to provide accurate representations of pre-storm ground conditions for areas that are designated high-priority because they have dense populations or valuable resources that are at risk from storm waves. Another purpose of the project is to develop a geomorphic (land feature) coastal classification that, with only minor modification, can be applied to most coastal regions in the United States. A Coastal Classification Map describing local geomorphic features is the first step toward determining the hazard vulnerability of an area. The Coastal Classification Maps of the National Assessment of Coastal Change Project present ground conditions such as beach width, dune elevations, overwash potential, and density of development. In order to complete a hazard vulnerability assessment, that information must be integrated with other information, such as prior storm impacts and beach stability. The Coastal Classification Maps provide much of the basic information for such an assessment and represent a critical component of a storm-impact forecasting capability. The map above shows the areas covered by this web site. Click on any of the location names or outlines to view the Coastal Classification Map for that area.

Comparing the information content of coral reef geomorphological and biological habitat maps, Amirantes Archipelago (Seychelles), Western Indian Ocean

NASA Astrophysics Data System (ADS)

Hamylton, S.; Andréfouët, S.; Spencer, T.

2012-10-01

Increasing the use of geomorphological map products in marine spatial planning has the potential to greatly enhance return on mapping investment as they are commonly two orders of magnitude cheaper to produce than biologically-focussed maps of benthic communities and shallow substrates. The efficacy of geomorphological maps derived from remotely sensed imagery as surrogates for habitat diversity is explored by comparing two map sets of the platform reefs and atolls of the Amirantes Archipelago (Seychelles), Western Indian Ocean. One mapping campaign utilised Compact Airborne Spectrographic Imagery (19 wavebands, 1 m spatial resolution) to classify 11 islands and associated reefs into 25 biological habitat classes while the other campaign used Landsat 7 + ETM imagery (7 bands, 30 m spatial resolution) to generate maps of 14 geomorphic classes. The maps were compared across a range of characteristics, including habitat richness (number of classes mapped), diversity (Shannon-Weiner statistic) and thematic content (Cramer's V statistic). Between maps, a strong relationship was revealed for habitat richness (R2 = 0.76), a moderate relationship for class diversity and evenness (R2 = 0.63) and a variable relationship for thematic content, dependent on site complexity (V range 0.43-0.93). Geomorphic maps emerged as robust predictors of the habitat richness in the Amirantes. Such maps therefore demonstrate high potential value for informing coastal management activities and conservation planning by drawing on information beyond their own thematic content and thus maximizing the return on mapping investment.

The topographic signature of anthropogenic geomorphic processes

NASA Astrophysics Data System (ADS)

Tarolli, P.; Sofia, G.

2014-12-01

Within an abiotic-dominated context, geomorphologic patterns and dynamics are single expressions of trade-offs between the physical resistance forces, and the mechanical and chemical forces related to climate and erosion. Recently, however, it has become essential for the geomorphological community to take into account also biota as a fundamental geomorphologic agent acting from local to regional scales. However, while there is a recent flourishing literature about the impacts of vegetation on geomorphic processes, the study of anthropogenic pressure on geomorphology is still at its early stages. Humans are indeed among the most prominent geomorphic agents, redistributing land surface, and causing drastic changes to the geomorphic organization of the landscape (e.g. intensive agriculture, urbanization), with direct consequences on land degradation and watershed response. The reconstruction or identification of artificial or anthropogenic topographies, therefore, provides a mechanism for quantifying anthropogenic changes to the landscape systems in the context of the Anthropocene epoch. High-resolution topographic data derived from the recent remote sensing technologies (e.g. lidar, SAR, SfM), offer now new opportunities to recognize better understand geomorphic processes from topographic signatures, especially in engineered landscapes where the direct anthropic alteration of processes is significant. It is possible indeed to better recognize human-induced geomorphic and anthropogenic features (e.g. road networks, agricultural terraces), and the connected erosion. The study presented here may allow improved understanding and targeted mitigation of the processes driving geomorphic changes during urban development and help guide future research directions for development-based watershed studies. Human society is deeply affecting the environment with consequences on the landscape. It is therefore fundamental to establish greater management control over the Earth's rapidly changing ecosystems. Tarolli, P. (2014). High-resolution topography for understanding Earth surface processes: opportunities and challenges, Geomorphology, 216, 295-312, doi:10.1016/j.geomorph.2014.03.008.

The geomorphic effect of recent storms - Quantifying meso scale abrasion across a shore platform

NASA Astrophysics Data System (ADS)

Cullen, Niamh; Bourke, Mary; Naylor, Larissa

2017-04-01

Boulder abrasion trails (BATs) are lineations on the surface of rock platforms formed by the movement of traction-load clasts by waves. They have been observed on a variety of platform lithologies, including limestone, granite and basalt. Despite previous reporting of these features, the abrasion styles and geomorphic work done by boulder transport has not been quantified. We present the first quantitative measurement of shore platform erosion by boulder transport during extreme storms that occurred in the winter of 2015-2016. Following two storm events in 2016 we mapped and measured 33 individual BATs on a sandstone platform on the west coast of Ireland. The total (minimum) abraded surface area was 10m2. The total (minimum) volume of material abraded was 0.2m3. In order to test the efficacy of this process during non-storm conditions we conducted field experiments on the same platform. We identified two sites on the platform that were similar, but differed in their intertidal roughness. We installed an RBR solo wave pressure transducer (PT) at 0m OD at both locations to record wave data. We measured platform roughness, determined as the fractal dimension of the platform profiles at both sites. We deployed an array of boulders of known dimensions and mass, parallel to the shoreline at 0.5m intervals from the PTs. The experiments were conducted 1. during relatively calm conditions and 2. during higher energy conditions. Data was collected for one tidal cycle. Any boulder displacement distance and direction was measured and geomorphic effects were documented. We find that BATs are formed under a range of wave energy conditions. Our observations indicate that along the North Atlantic coastline, BATs can occur at a high frequency, only limited by sediment supply. Our data show that abrasion by boulder transport is a potentially significant geomorphological process acting to abrade platforms under contemporary climate conditions. In addition, our preliminary findings suggest that platform roughness exerts a strong influence on wave energy and potential boulder transport. We find that abrasion of the platform surface is a fundamentally important process which contributes to lowering of the platform surface over time.

Geomorphic changes in Ras Al-Subiyah area, Kuwait

NASA Astrophysics Data System (ADS)

Al Hurban, A.; El-Gamily, H.; El-Sammak, A.

2008-06-01

The Ras Al-Subiyah area is considered one of the most promising areas in Kuwait for future development. This development will include a new town called Subiyah and its associated infrastructure. This area is also being considered as the location for connection between Boubyan Island, which is now undergoing major development and the Kuwait mainland. The present study investigates the geomorphology of the Ras Al-Sabiyah area in the northern sector of Kuwait. The study area is generally flat, and it is located west of the Jal Az-Zor escarpment. It is bordered on the east by the Khor Al-Sabiyah tidal channel and on the south by Kuwait Bay. The area receives sediments from several sources; currently the most important are aeolian sediments and the deposition of mud delivered through the Khor Al-Sabiyah from the Iraqi marshes. The study area has been subjected to severe environmental changes due to the Gulf wars and the drainage of Iraqi marshes and the associated artificial changes in fluvial system. Twenty-two surface sediments were collected from the Ras Al-Subiyah area. Samples were collected to include the main geomorphologic characteristic features of the study area. Field observations and remote sensing images from 1990 and 2001 were used to produce an updated geomorphologic map for the Ras Al-Subiyah and a map showing geomorphic changes between 1990 and 2001. Grain size of the surface sediment ranges from gravel to medium sand. In general, grain size statistical analysis indicates that most of the areas are composed of two or more classes of sands transported and deposited from different sources including aeolian, sabkhas, river and the bays. The variability in the grain size statistical parameters may be attributed to the complexity of surface morphology as well as the diversity in the type of depositional environment in the Ras Al-Subiyah area. The total area subjected to change during the 12-year period (1990 2001) is about 32 km2 as calculated using GIS techniques.

Geomorphology, active duplexing, and earthquakes within the Central Himalayan seismic gap

NASA Astrophysics Data System (ADS)

Morell, K. D.; Sandiford, M.; Rajendran, C. C.; Rajendran, K.

2013-12-01

The ~500 km long 'Central Himalayan seismic gap' of northwest India, is the largest section of the Himalaya that has not experienced a very large earthquake (Mw > 7.0) in the past 200-500 years. The slip deficit associated with this seismic quiescence has led many to suggest that the region is overdue for a great earthquake (Mw >8), an event which could be potentially devastating given the region's high population (>10 million). Despite the recognition that the region is under considerable seismic risk, the geometry of active fault structures that could potentially fail during large earthquakes remains poorly defined. This has arisen, to a certain extent, because moderate earthquakes, such as the Mw 6.3 1999 event near the city of Chamoli and the Mw 7.0 1991 earthquake near Uttarkashi (responsible for ~1000 deaths), have not produced obvious surface ruptures and do not appear to coincide with surficially mapped faults. We present new geomorphic and river longitudinal profile data that define a prominent ~400 km long distinctive geomorphic transition at the base of the high Himalaya in the seismic gap, defined as a sharp dividing line north of which there are significant increases in normalized river steepness (ksn), hillslope angles, and local relief. We interpret the morphologic changes across the geomorphic boundary to be produced due to a northward increase in rock uplift rate, given that the boundary cross-cuts mapped structures and lithologic contacts, yet coincides exactly with: 1) the axial trace of the geophysically-imaged ramp-flat transition in the Main Himalayan Thrust, 2) significant northward increases in instrumentally-recorded seismicity, and 3) an order of magnitude change in published Ar-Ar bedrock cooling ages. The available datasets suggest that such an increase in rock uplift rate is best explained by a ~400 km long by ~50 km wide active duplex along the Main Himalayan Thrust ramp, with the leading edge of the duplex giving rise to the geomorphic boundary. The observation that the geomorphic boundary of the seismic gap lies ~350 km to the west of the analogous PT2 of Central Nepal (yet there is no such well-defined physiographic transition in the region between them) suggests that the changing along-strike character of the middle/high Himalaya transition could reflect changes, on the order of 102 km, in the geometry and/or kinematics of the plate boundary thrust along-strike. These along-strike variations could segment the plate boundary and effectively restrict the locality and rupture length of large earthquakes. This hypothesis is supported by historical records of seismicity which indicate that the Mw ~7.5 earthquake of 1803 occurred roughly within the section of the seismic gap containing the geomorphic boundary, and the Mw ~7.7 earthquake of 1833 ruptured the ~350 km long section of the plate boundary occupied by the Nepalese PT2.

Geomorphic response to tectonically-induced ground deformation in the Wabash Valley

USGS Publications Warehouse

Fraser, G.S.; Thompson, T.A.; Olyphant, G.A.; Furer, L.; Bennett, S.W.

1997-01-01

Numerous low- to moderate-intensity earthquakes have been recorded in a zone of diffuse modern seismicity in southwest Indiana, southeast Illinois, and northernmost Kentucky. Structural elements within the zone include the Wabash Valley Fault System, the LaSalle Anticlinal Belt in western Illinois, and the Rough Creek-Shawneetown Fault System in northern Kentucky. The presence of seismically-induced liquefaction features in the near-surface alluvial sediments in the region indicates that strong ground motion has occurred in the recent geological past, but because the glacial and alluvial sediments in the Wabash Valley appear to be otherwise undisturbed, post-Paleozoic ground deformation resulting from movement on these structural elements has not yet been documented. Morphometric analysis of the land surface, detailed mapping of geomorphic elements in the valley, reconnaissance drilling of the Holocene and Pleistocene alluvium, and structural analysis of the bedrock underlying the valley were used to determine whether the geomorphology of the valley and the patterns of alluviation of the Wabash River were affected by surface deformation associated with the seismic zone during the late Pleistocene and Holocene. Among the observed features in the valley that can be attributed to deformation are: (1) tilting of the modern land surface to the west, (2) preferred channel migration toward the west side of the valley, with concomitant impact on patterns of soil development and sedimentation rate, (3) a convex longitudinal profile of the Wabash River where it crosses the LaSalle Anticlinal Belt, and (4) increased incision of the river into its floodplain downstream from the anticlinal belt.

Geomorphic Function and Restoration Potential of Spring Creeks in Southeastern Idaho: Analysis and Communication

NASA Astrophysics Data System (ADS)

Hanrahan, T. P.; Hill, Z.; Levell, A.; Maguire, T.; Risso, D.

2014-12-01

A large wetland and floodplain complex adjacent to the Snake River in southeastern Idaho, USA, encompasses numerous spring-fed creeks that originate on the floodplain and discharge at their confluence with the Snake River and American Falls Reservoir. Resource managers are implementing a program to restore these spring creeks for the recovery of Yellowstone cutthroat trout and ecosystem health. Our objectives were to evaluate the physical characteristics of these spring creeks, develop a conceptual model of their geomorphic function, compare the restoration potential of individual reaches, and communicate our findings to a broad audience of resource managers and regional stakeholders in order to foster restoration planning. A geomorphic assessment along 38 km of three spring creeks was completed by collecting data at several transects within distinct geomorphic reaches, and by collecting data continuously throughout all reaches. These data were summarized in a GIS database and used to quantify the overall geomorphic functioning of each reach. The geomorphic functional scores were scaled from 0% (non-functional) to 100% (fully functional). Among all three spring creeks, geomorphic function ranged from 29% to 63%, with bank conditions and riparian vegetation being the primary causes of overall channel degradation. Results from the geomorphic assessment fostered the development of a conceptual model for spring creek function, whereby degraded bank conditions represent the primary controlling factor of decreased geomorphic function and fish habitat quality. The reach-based geomorphic functional scoring provides an indicator of relative restoration potential for each reach, and is one of the factors used in determining site-specific priorities for protecting, enhancing, and restoring spring creeks on the Fort Hall Bottoms. The study results, conceptual model and restoration strategy were communicated to resource managers and regional stakeholders through a graphically-rich, large format atlas document. Presentation of hard copy and electronic versions of maps and infographics fostered a high level of engagement among those interested in restoring these spring creek systems.

Quantitative analysis of geomorphic processes using satellite image data at different scales

NASA Technical Reports Server (NTRS)

Williams, R. S., Jr.

1985-01-01

When aerial and satellite photographs and images are used in the quantitative analysis of geomorphic processes, either through direct observation of active processes or by analysis of landforms resulting from inferred active or dormant processes, a number of limitations in the use of such data must be considered. Active geomorphic processes work at different scales and rates. Therefore, the capability of imaging an active or dormant process depends primarily on the scale of the process and the spatial-resolution characteristic of the imaging system. Scale is an important factor in recording continuous and discontinuous active geomorphic processes, because what is not recorded will not be considered or even suspected in the analysis of orbital images. If the geomorphic process of landform change caused by the process is less than 200 m in x to y dimension, then it will not be recorded. Although the scale factor is critical, in the recording of discontinuous active geomorphic processes, the repeat interval of orbital-image acquisition of a planetary surface also is a consideration in order to capture a recurring short-lived geomorphic process or to record changes caused by either a continuous or a discontinuous geomorphic process.

Hydro-geomorphic connectivity and landslide features extraction to identifying potential threats and hazardous areas

NASA Astrophysics Data System (ADS)

Tarolli, Paolo; Fuller, Ian C.; Basso, Federica; Cavalli, Marco; Sofia, Giulia

2017-04-01

Hydro-geomorphic connectivity has significantly emerged as a new concept to understand the transfer of surface water and sediment through landscapes. A further scientific challenge is determining how the concept can be used to enable sustainable land and water management. This research proposes an interesting approach to integrating remote sensing techniques, connectivity theory, and geomorphometry based on high-resolution digital terrain model (HR-DTMs) to automatically extract landslides crowns and gully erosion, to determine the different rate of connectivity among the main extracted features and the river network, and thus determine a possible categorization of hazardous areas. The study takes place in two mountainous regions in the Wellington Region (New Zealand). The methodology is a three step approach. Firstly, we performed an automatic detection of the likely landslides crowns through the use of thresholds obtained by the statistical analysis of the variability of landform curvature. After that, the research considered the Connectivity Index to analyse how a complex and rugged topography induces large variations in erosion and sediment delivery in the two catchments. Lastly, the two methods have been integrated to create a unique procedure able to classify the different rate of connectivity among the main features and the river network and thus identifying potential threats and hazardous areas. The methodology is fast, and it can produce a detailed and updated inventory map that could be a key tool for erosional and sediment delivery hazard mitigation. This fast and simple method can be a useful tool to manage emergencies giving priorities to more failure-prone zones. Furthermore, it could be considered to do a preliminary interpretations of geomorphological phenomena and more in general, it could be the base to develop inventory maps. References Cavalli M, Trevisani S, Comiti F, Marchi L. 2013. Geomorphometric assessment of spatial sediment connectivity in small Alpine catchments. Geomorphology 188: 31-41 DOI: 10.1016/j.geomorph.2012.05.007 Sofia G, Dalla Fontana G, Tarolli P. 2014. High-resolution topography and anthropogenic feature extraction: testing geomorphometric parameters in floodplains. Hydrological Processes 28 (4): 2046-2061 DOI: 10.1002/hyp.9727 Tarolli P, Sofia G, Dalla Fontana G. 2012. Geomorphic features extraction from high-resolution topography: landslide crowns and bank erosion. Natural Hazards 61 (1): 65-83 DOI: 10.1007/s11069-010-9695-2

Correlation between land cover and ground vulnerability in Alexandria City (Egypt) using time series SAR interferometry and optical Earth observation data

NASA Astrophysics Data System (ADS)

Seleem, T.; Stergiopoulos, V.; Kourkouli, P.; Perrou, T.; Parcharidis, Is.

2017-10-01

The main scope of this study is to investigate the potential correlation between land cover and ground vulnerability over Alexandria city, Egypt. Two different datasets for generating ground deformation and land cover maps were used. Hence, two different approaches were followed, a PSI approach for surface displacement mapping and a supervised classification algorithm for land cover/use mapping. The interferometric results show a gradual qualitative and quantitative differentiation of ground deformation from East to West of Alexandria government. We selected three regions of interest, in order to compare the obtained interferometric results with the different land cover types. The ground deformation may be resulted due to different geomorphic and geologic factors encompassing the proximity to the active deltaic plain of the Nile River, the expansion of the urban network within arid regions of recent deposits, the urban density increase, and finally the combination of the above mentioned parameters.

Monitoring of heavy flooding by orbital remote sensing: The example of the Doce river valley. [Doce River Valley, Brazil

NASA Technical Reports Server (NTRS)

Dejesusparada, N. (Principal Investigator); Novo, E. M. L. D.; Dossantos, A. P.

1981-01-01

The application of temporal LANDSAT data to study floods was verified, and the natural features responsible for this phenomenon were surveyed using the Doce river valley as a test site, because of the catastrophic (1978-1979) flood. Data from LANDSAT images and CCT's were used. Geomorphical mapping evaluated morphostructural features. Seven and nine classes of water surfaces for dry and rainy seasons were analyzed. The magnitude of the changes from preflood to postflood stage are estimated. The single Pixel program was applied to correlate the drainage basin characteristics to the grey level of LANDSAT data.

Remote sensing studies of the geomorphology of Surtsey, 1987-1991

USGS Publications Warehouse

Garvin, James B.; Williams, R. S.

1992-01-01

The volcanic island of Surtsey, formed by explosive submarine and effusive subaerial eruptions between November 1963 and June 1967, consists of a complex combination of primary and redeposited tephra and alkaline olivine basalt lava flows in a 2.5 km2 area (Thorarinsson, 1967; Thorarinsson et al., 1964; Fridriksson, 1975). During the past 24 years, wave and wind erosion of this subaerial mid-ocean ridge (MOR) vent complex have modified Surtsey's coastal morphology, including the deposition of a 0.5 km-long northern peninsula (ness) composed of tephra and rounded lava fragments derived from the southern half of the island. Detailed geomorphologic and sedimentologic mapping of the various surface units now present on Surtsey has been accomplished throughout the history of the evolving island, most recently by Calles et al. (1980) and Ingolfsson (1980). On the basis of these studies, an effort to quantify the topographic characteristics of the primary geomorphic units on the island was initiated by the National Aeronautics and Space Administration (NASA) and the United States Geological Survey (USGS) in 1987. The objective has been to directly measure the microtopographic properties of the widest range of surface types possible, with special emphasis on the pristine or dynamic types. While large-scale topographic maps of Surtsey were prepared in 1968 and 1975 (Norrman, 1980; Norrman and Erlingsson, 1991; Calles et al, 1980), and geodetic leveling surveys have been carried out (Moore, 1980), there have been no recent attempts to geodetically determine the local topography of the island. Because of the rapid rates of geomorphic processes, such as erosion and deposition, on a small, geologically isolated volcanic island such as Surtsey, it is desirable to determine the meter-scale topographic character of its surface units and landforms, and later a remeasurement of the same surfaces to further quantify volumetric change, subsidence, and process rates. In addition, precise measurements of sub-meter-scale topography of pristine geologic surfaces provides necessary data for the investigation of whether various geologic processes demonstrate fractal or self-affine behavior at a range of length-scales within the interval 0.1 in to 1 km. Thus Surtsey offers a unique opportunity to apply new remote sensing techniques to the measurement of the evolving surface "roughness" characteristics of pristine geologic surfaces within an historically well-monitored environment.

Comparison between flood prone areas' geomorphic features in the Abruzzo region

NASA Astrophysics Data System (ADS)

Orlando, D.; Giglioni, M.; Magnaldi, S.

2017-07-01

Flood risk maps are one of the main non-structural measures for risk mitigation, but, as the risk knowledge degree is directly proportional to the community interest and financial capability, many sites are devoid of flood inundation areas studies. Recently many authors have investigated the capability of flood prone areas individuation with geomorphological DIGITAL ELEVATION MODEL(DEM) based approaches. These approaches highlight the role of geomorphic features derived from DEM, in this case slope, curvature, elevation, and topographic wetness index, to preliminary inundated areas' identification, without using hydraulic simulations. The present studies aim to analyze the geomorphic features of different hazard levels that lie under the identified inundated areas that have been carried out by the Abruzzo Region Basin Authority. The Aterno-Pescara and Foro river basins have been investigated. The results show that the characteristics of the flooded areas can be clearly distinguished from those of the entire basin,however, the difficultly of geomorphic features in individuatingthe areas of different hazard classifications is obvious.

An integrated Landsat/ancillary data classification of desert rangeland

NASA Technical Reports Server (NTRS)

Price, K. P.; Ridd, M. K.; Merola, J. A.

1985-01-01

Range inventorying methods using Landsat MSS data, coupled with ancillary data were examined. The study area encompassed nearly 20,000 acres in Rush Valley, UT. The vegetation is predominately desert shrub and annual grasses, with same annual forbs. Three Landsat scenes were evaluated using a Kauth-Thomas brightness/greenness data transformation (May, June, and August dates). The data was classified using a four-band maximum-likelihood classifier. A print map was taken into the field to determine the relationship between print symbols and vegetation. It was determined that classification confusion could be greatly reduced by incorporating geomorphic units and soil texture (coarse vs fine) into the classification. Spectral data, geomorphic units, and soil texture were combined in a GIS format to produce a final vegetation map identifying 12 vegetation types.

An integrated LANDSAT/ancillary data classification of desert rangeland

NASA Technical Reports Server (NTRS)

Price, K. P.; Ridd, M. K.; Merola, J. A.

1984-01-01

Range inventorying methods using LANDSAT MSS data, coupled with ancillary data were examined. The study area encompassed nearly 20,000 acres in Rush Valley, Utah. The vegetation is predominately desert shrub and annual grasses, with some annual forbs. Three LANDSAT scenes were evaluated using a Kauth-Thomas brightness/greenness data transformation (May, June, and August dates). The data was classified using a four-band maximum-likelihood classifier. A print map was taken into the field to determine the relationship between print symbols and vegetation. It was determined that classification confusion could be greatly reduced by incorporating geomorphic units and soil texture (coarse vs fine) into the classification. Spectral data, geomorphic units, and soil texture were combined in a GIS format to produce a final vegetation map identifying 12 vegetation types.

Geomorphic Map of Worcester County, Maryland, Interpreted from a LIDAR-Based, Digital Elevation Model

USGS Publications Warehouse

Newell, Wayne L.; Clark, Inga

2008-01-01

A recently compiled mosaic of a LIDAR-based digital elevation model (DEM) is presented with geomorphic analysis of new macro-topographic details. The geologic framework of the surficial and near surface late Cenozoic deposits of the central uplands, Pocomoke River valley, and the Atlantic Coast includes Cenozoic to recent sediments from fluvial, estuarine, and littoral depositional environments. Extensive Pleistocene (cold climate) sandy dune fields are deposited over much of the terraced landscape. The macro details from the LIDAR image reveal 2 meter-scale resolution of details of the shapes of individual dunes, and fields of translocated sand sheets. Most terrace surfaces are overprinted with circular to elliptical rimmed basins that represent complex histories of ephemeral ponds that were formed, drained, and overprinted by younger basins. The terrains of composite ephemeral ponds and the dune fields are inter-shingled at their margins indicating contemporaneous erosion, deposition, and re-arrangement and possible internal deformation of the surficial deposits. The aggregate of these landform details and their deposits are interpreted as the products of arid, cold climate processes that were common to the mid-Atlantic region during the Last Glacial Maximum. In the Pocomoke valley and its larger tributaries, erosional remnants of sandy flood plains with anastomosing channels indicate the dynamics of former hydrology and sediment load of the watershed that prevailed at the end of the Pleistocene. As the climate warmed and precipitation increased during the transition from late Pleistocene to Holocene, dune fields were stabilized by vegetation, and the stream discharge increased. The increased discharge and greater local relief of streams graded to lower sea levels stimulated down cutting and created the deeply incised valleys out onto the continental shelf. These incised valleys have been filling with fluvial to intertidal deposits that record the rising sea level and warmer, more humid climate in the mid-Atlantic region throughout the Holocene. Thus, the geomorphic details provided by the new LIDAR DEM actually record the response of the landscape to abrupt climate change. Holocene trends and land-use patterns from Colonial to modern times can also be interpreted from the local macro- scale details of the landscape. Beyond the obvious utility of these data for land-use planning and assessments of resources and hazards, the new map presents new details on the impact of climate changes on a mid-latitude, outer Coastal plain landscape.

Andrean examples of mega-geomorphology themes

NASA Technical Reports Server (NTRS)

Bloom, A. L.

1985-01-01

Geomorphic (or physiographic) provinces have been a well known and useful method of regional landform classification for a century. Every earth scientist will recognize a phrase such as Appalachian Plateau or Southern Rocky Mountains as defining a discrete region of consistent geologic structure that has experienced a similar interval of erosion by a similar process or set of processes. The geomorphic provinces formalized in the United States by Fenneman in the 1920's continue to be highly satisfactory even though some boundaries were only vaguely drawn. Mosaics of LANDSAT images illustrate better than any earlier maps the validity and coherence of Fenneman's provinces. The concept of geomorphic provinces has been used subconsciously or intuitively, to describe the relief of the ocean floor and the topography of the Moon and other planets.

Using surface curvature to map geomorphic process regimes in a bedrock landscape, Henry Mountains, Utah

NASA Astrophysics Data System (ADS)

Corbett, S.; Sklar, L. S.; Davis, J.

2009-12-01

Linkages between form and process are much better understood in soil-mantled landscapes than in bedrock landscapes, despite the wide occurrence of bedrock landscapes in arid and mountainous terrain. Soil-mantled hillslope topography can be characterized by hillslope gradient and its spatial derivative, which is commonly referred to as curvature and defined as the Laplacian of elevation. Surface curvature can also be quantified using techniques that are invariant to the orientation of the surface. These approaches are useful in many geoscience applications, including structural analysis of folded surfaces within deforming crustal blocks. Here we explore the use of surface curvature of bedrock topography as a metric to identify and map distinct geomorphic process regimes in a landscape devoid of soil cover. Our study site is Simpson Creek, a 2.5 km2 watershed on the east flank of Mt. Hillers in the Henry Mountains, Utah, which drains to the Colorado River in Glen Canyon. The land surface is entirely exposed Navajo Sandstone bedrock, with isolated patches of wind-blown sand deposits. The channel network is discontinuous, with alternating reaches of steep, deeply-incised, frequently-potholed slots, and lower-gradient, sand-bedded channels. Hillslope topography is characterized by dome-shaped and sub-linear ridges, and is influenced by prominent structural joints. We calculate two measures of the surface-normal curvature using an ALSM-derived digital elevation model. The mean and Gaussian surface curvatures are the average and product respectively of the magnitudes of the maximum and minimum curvature vectors, obtained by differentiating a polynomial fit at each point in a grid with 1 m spacing. Plots of mean versus Gaussian curvature reveal distinct clusters of landscape elements, which we associate with specific process regimes. In this parameter space, there are four quadrants, classified as dome, basin, synformal saddle and antiformal saddle. The channel and valley network corresponds to negative mean curvature, where concave and convex profile segments plot as basins and synformal saddles (positive and negative Gaussian curvature) respectively. We are able to use surface curvature to map what can be interpreted as bedrock channel width, as well as knickpoints, sand-bedrock bed transitions, and even individual large potholes. The tips of the channel network also have a distinct surface-curvature signature, and are associated with prominent polygonal bedrock fracturing at the sub-meter scale. In the hillslope portion of the landscape (positive mean curvature), the distribution of landscape elements has several modes, including a characteristic dome curvature that may be associated with sheet jointing and weathering-influenced exfoliation erosion, and an antiformal saddle curvature where solution pits occur, particularly on higher ridges most distant from the main-stem slot canyon channels. One key goal of this work is to quantify the effect of variable erosion rate on the distribution of process regime as expressed by these characteristic modes of bedrock surface curvature.

Lunar and Planetary Science XXXV: Mars: Surface Coatings, Mineralogy, and Surface Properties

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Mars: Surface Coatings, Mineralogy, and Surface Properties" contained the following reports:High-Silica Rock Coatings: TES Surface-Type 2 and Chemical Weathering on Mars; Old Desert Varnish-like Coatings and Young Breccias at the Mars Pathfinder Landing Site; Analyses of IR-Stealthy and Coated Surface Materials: A Comparison of LIBS and Reflectance Spectra and Their Application to Mars Surface Exploration; Contrasting Interpretations of TES Spectra of the 2003 Rover:Opportunity-Landing Site: Hematite Coatings and Gray Hematite; A New Hematite Formation Mechanism for Mars; Geomorphic and Diagenetic Analogs to Hematite Regions on Mars: Examples from Jurassic Sandstones of Southern Utah, USA; The Geologic Record of Early Mars: A Layered, Cratered, and "Valley-"ed: Volume; A Simple Approach to Estimating Surface Emissivity with THEMIS; A Large Scale Topographic Correction for THEMIS Data; Thermophysical Properties of Meridiani Planum, Mars; Thermophysical and Spectral Properties of Gusev, the MER-Spirit Landing Site on Mars; Determining Water Content of Geologic Materials Using Reflectance Spectroscopy; and Global Mapping of Martian Bound Water at 6.1 Microns Based on TES Data: Seasonal Hydration.

Modeling hydrologic and geomorphic hazards across post-fire landscapes using a self-organizing map approach

USGS Publications Warehouse

Friedel, Michael J.

2011-01-01

Few studies attempt to model the range of possible post-fire hydrologic and geomorphic hazards because of the sparseness of data and the coupled, nonlinear, spatial, and temporal relationships among landscape variables. In this study, a type of unsupervised artificial neural network, called a self-organized map (SOM), is trained using data from 540 burned basins in the western United States. The sparsely populated data set includes variables from independent numerical landscape categories (climate, land surface form, geologic texture, and post-fire condition), independent landscape classes (bedrock geology and state), and dependent initiation processes (runoff, landslide, and runoff and landslide combination) and responses (debris flows, floods, and no events). Pattern analysis of the SOM-based component planes is used to identify and interpret relations among the variables. Application of the Davies-Bouldin criteria following k-means clustering of the SOM neurons identified eight conceptual regional models for focusing future research and empirical model development. A split-sample validation on 60 independent basins (not included in the training) indicates that simultaneous predictions of initiation process and response types are at least 78% accurate. As climate shifts from wet to dry conditions, forecasts across the burned landscape reveal a decreasing trend in the total number of debris flow, flood, and runoff events with considerable variability among individual basins. These findings suggest the SOM may be useful in forecasting real-time post-fire hazards, and long-term post-recovery processes and effects of climate change scenarios.

Faults and structure in the Pierre Shale, central south Dakota

USGS Publications Warehouse

Nichols, Thomas C.; Collins, Donley S.; Jones-Cecil, Meridee; Swolfs, Henri S.

1994-01-01

Numerous faults observed at the surface and (or) determined by geometric and geophysical methods to be present as much as several hundred meters below the surface (near-surface faults) have been mapped in a 2,000-km2 area west of Pierre, S. Dakota. Many of these faults surround an east-west-trending structural high that has been mapped on the lower part of the Virgin Creek Member of the Pierre Shale. Generally, the geometry and displacement of many of the faults precludes slumping from surficial erosion as a mechanism to explain the faults. Seismic-reflection data indicate that several of the faults directly overlie faults in Precambrian basement that have cumulative vertical displacements of as much as 340 m. The structural high is interpreted to have been uplifted by displacements along faults that cut Upper Cretaceous sedimentary rocks. Recent low-level seismicity and fluvial-geomorphic studies of stream patterns, gradients, and orders suggest that rejuvenation of drainages may be taking place as a result of rebound or other tectonic activity. The studies indicate that repeated uplift and subsidence may have been the cause of extensive faulting mapped in the Pierre Shale since its deposition in Cretaceous time. Surficial fault displacements that cause damage to engineered structures are thought to be the result of construction-induced rebound in the Pierre Shale, although tectonic uplift cannot be ruled out as a cause.

Tundra landform and vegetation productivity trend maps for the Arctic Coastal Plain of northern Alaska

NASA Astrophysics Data System (ADS)

Lara, Mark J.; Nitze, Ingmar; Grosse, Guido; McGuire, A. David

2018-04-01

Arctic tundra landscapes are composed of a complex mosaic of patterned ground features, varying in soil moisture, vegetation composition, and surface hydrology over small spatial scales (10-100 m). The importance of microtopography and associated geomorphic landforms in influencing ecosystem structure and function is well founded, however, spatial data products describing local to regional scale distribution of patterned ground or polygonal tundra geomorphology are largely unavailable. Thus, our understanding of local impacts on regional scale processes (e.g., carbon dynamics) may be limited. We produced two key spatiotemporal datasets spanning the Arctic Coastal Plain of northern Alaska (~60,000 km2) to evaluate climate-geomorphological controls on arctic tundra productivity change, using (1) a novel 30 m classification of polygonal tundra geomorphology and (2) decadal-trends in surface greenness using the Landsat archive (1999-2014). These datasets can be easily integrated and adapted in an array of local to regional applications such as (1) upscaling plot-level measurements (e.g., carbon/energy fluxes), (2) mapping of soils, vegetation, or permafrost, and/or (3) initializing ecosystem biogeochemistry, hydrology, and/or habitat modeling.

Tundra landform and vegetation productivity trend maps for the Arctic Coastal Plain of northern Alaska.

PubMed

Lara, Mark J; Nitze, Ingmar; Grosse, Guido; McGuire, A David

2018-04-10

Arctic tundra landscapes are composed of a complex mosaic of patterned ground features, varying in soil moisture, vegetation composition, and surface hydrology over small spatial scales (10-100 m). The importance of microtopography and associated geomorphic landforms in influencing ecosystem structure and function is well founded, however, spatial data products describing local to regional scale distribution of patterned ground or polygonal tundra geomorphology are largely unavailable. Thus, our understanding of local impacts on regional scale processes (e.g., carbon dynamics) may be limited. We produced two key spatiotemporal datasets spanning the Arctic Coastal Plain of northern Alaska (~60,000 km 2 ) to evaluate climate-geomorphological controls on arctic tundra productivity change, using (1) a novel 30 m classification of polygonal tundra geomorphology and (2) decadal-trends in surface greenness using the Landsat archive (1999-2014). These datasets can be easily integrated and adapted in an array of local to regional applications such as (1) upscaling plot-level measurements (e.g., carbon/energy fluxes), (2) mapping of soils, vegetation, or permafrost, and/or (3) initializing ecosystem biogeochemistry, hydrology, and/or habitat modeling.

Evaluation of SIR-B imagery for geologic and geomorphic mapping, hydrology, and oceanography in Australia

NASA Technical Reports Server (NTRS)

Honey, F. R.; Simpson, C. J.; Huntington, J.; Horwitz, R.; Byrne, G.; Nilsson, C.

1984-01-01

The objectives of a study to evaluate the potential of Shuttle Imaging Radar-B (SIR-B) imagery for various applications are outlined. Specific goals include: the development of techniques for registration multiple acquisition, varied illumination, and incidence-angle SIR-B imagery, and a model for estimation of the relative contributions to the backscattered radiation of topography, surface roughness, and dielectric and conductivity components; (2) the evaluation of SIR-B imagery for delineation of agricultural lands affected by secondary salinity in the southwest and southeast agricultural regions of Australia; (3) the development of techniques for application of SIR-B imagery for geologic, geomorphologic and soils mapping and mineral exploration; and (4) the evaluation of the use of SIR-B imagery in determining ocean currents, current shear patterns, internal waves and bottom features for specific locations off the Australian coast.

Effects of Fault Segmentation, Mechanical Interaction, and Structural Complexity on Earthquake-Generated Deformation

ERIC Educational Resources Information Center

Haddad, David Elias

2014-01-01

Earth's topographic surface forms an interface across which the geodynamic and geomorphic engines interact. This interaction is best observed along crustal margins where topography is created by active faulting and sculpted by geomorphic processes. Crustal deformation manifests as earthquakes at centennial to millennial timescales. Given that…

Applications of Skylab EREP photographs to mapping of landforms and environmental geology in the Great Plains and Midwest. [Illinois, Iowa, Kansas, Missouri, Nebraska, and South Dakota

NASA Technical Reports Server (NTRS)

Morrison, R. B. (Principal Investigator)

1974-01-01

The author has identified the following significant results. The utility of Skylab 2 and 3 S-190A multispectral photos for environmental-geologic/geomorphic applications is being tested by using them to prepare 1:250,000-scale maps of geomorphic features, surficial geology, geologic linear features, and soil associations of large, representative parts of the Great Plains and Midwest. Parts of Nebraska, Iowa, Missouri, and South Dakota were mapped. The maps were prepared primarily by interpretation of the S-190A photos, supplemented by information from topographic, geologic, and soil maps and reports. The color band provides the greatest information on geology, soils, and geomorphology; its resolution also is the best of all the multispectral bands and permits maximum detail of mapping. The color-IR band shows well the differences in soil drainage and moisture, and vegetative types, but has only moderate resolution. The B/W-red band is superior for topographic detail and stream alinements. The B/W-infrared bands best show differences in soil moisture and drainage but have poor resolution, especially those from SL 2. The B/W-green band generally is so low contrast and degraded by haze as to be nearly useless. Where stereoscopic coverage is provided, interpretation and mapping are done most efficiently using a Kern PG-2 stereoplotter.

Geomorphic Consequences of Volcanic Eruptions in Alaska: A Review

USGS Publications Warehouse

Waythomas, Christopher F.

2015-01-01

Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta–Katmai eruption, the 1989–1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed.A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment–water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite large, with flow volumes in the range of 107–109 m3. A review of the lahars generated during the 2009 eruption of Redoubt volcano will illustrate the geomorphic impacts of lahars on stream channels and riparian habitat. Although much work is needed to develop a comprehensive understanding of the geomorphic consequences of volcanic activity in Alaska, this review provides a synthesis of some of the best-studied eruptions and perhaps will serve as a starting point for future work on this topic.

Geomorphic consequences of volcanic eruptions in Alaska: A review

USGS Publications Warehouse

Waythomas, Christopher F.

2015-01-01

Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta–Katmai eruption, the 1989–1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed.A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment–water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite large, with flow volumes in the range of 107–109 m3. A review of the lahars generated during the 2009 eruption of Redoubt volcano will illustrate the geomorphic impacts of lahars on stream channels and riparian habitat. Although much work is needed to develop a comprehensive understanding of the geomorphic consequences of volcanic activity in Alaska, this review provides a synthesis of some of the best-studied eruptions and perhaps will serve as a starting point for future work on this topic.

Comparison of Different Machine Learning Algorithms for Lithological Mapping Using Remote Sensing Data and Morphological Features: A Case Study in Kurdistan Region, NE Iraq

NASA Astrophysics Data System (ADS)

Othman, Arsalan; Gloaguen, Richard

2015-04-01

Topographic effects and complex vegetation cover hinder lithology classification in mountain regions based not only in field, but also in reflectance remote sensing data. The area of interest "Bardi-Zard" is located in the NE of Iraq. It is part of the Zagros orogenic belt, where seven lithological units outcrop and is known for its chromite deposit. The aim of this study is to compare three machine learning algorithms (MLAs): Maximum Likelihood (ML), Support Vector Machines (SVM), and Random Forest (RF) in the context of a supervised lithology classification task using Advanced Space-borne Thermal Emission and Reflection radiometer (ASTER) satellite, its derived, spatial information (spatial coordinates) and geomorphic data. We emphasize the enhancement in remote sensing lithological mapping accuracy that arises from the integration of geomorphic features and spatial information (spatial coordinates) in classifications. This study identifies that RF is better than ML and SVM algorithms in almost the sixteen combination datasets, which were tested. The overall accuracy of the best dataset combination with the RF map for the all seven classes reach ~80% and the producer and user's accuracies are ~73.91% and 76.09% respectively while the kappa coefficient is ~0.76. TPI is more effective with SVM algorithm than an RF algorithm. This paper demonstrates that adding geomorphic indices such as TPI and spatial information in the dataset increases the lithological classification accuracy.

A Photographic Atlas of Rock Breakdown Features in Geomorphic Environments

NASA Technical Reports Server (NTRS)

Bourke, Mary C. (Editor); Brearley, J. Alexander; Haas, Randall; Viles, Heather A.

2007-01-01

A primary goal of geomorphological enquiry is to make genetic associations between process and form. In rock breakdown studies, the links between process, inheritance and lithology are not well constrained. In particular, there is a need to establish an understanding of feature persistence. That is, to determine the extent to which in situ rock breakdown (e.g., aeolian abrasion or salt weathering) masks signatures of earlier geomorphic transport processes (e.g., fluvial transport or crater ejecta). Equally important is the extent to which breakdown during geomorphic transport masks the imprint of past weathering. The use of rock features in this way raises the important question: Can features on the surface of a rock reliably indicate its geomorphic history? This has not been determined for rock surfaces on Earth or other planets. A first step towards constraining the links between process, inheritance, and morphology is to identify pristine features produced by different process regimes. The purpose of this atlas is to provide a comprehensive image collection of breakdown features commonly observed on boulders in different geomorphic environments. The atlas is intended as a tool for planetary geoscientists and their students to assist in identifying features found on rocks on planetary surfaces. In compiling this atlas, we have attempted to include features that have formed 'recently' and where the potential for modification by another geomorphic process is low. However, we acknowledge that this is, in fact, difficult to achieve when selecting rocks in their natural environment. We group breakdown features according to their formative environment and process. In selecting images for inclusion in the atlas we were mindful to cover a wide range of climatic zones. For example, in the weathering chapter, clast features are shown from locations such as the hyper-arid polar desert of Antarctica and the semi-arid canyons of central Australia. This is important as some features (e.g., alveoli) occur across climate regimes. We have drawn on the published geomorphological literature and our own field experience. We use, where possible, images of extrusive igneous rocks as the data returned from Mars, Venus and the Moon indicates that this is the predominant rock type. One of the purposes of this atlas is to expand the range of surface features that are known to indicate a particular geomorphic environment or process history. The surface features on boulders in some environments such as aeolian and weathering are well understood. In contrast, those in fluvial or ejecta environments are not. Therefore we have presented a comprehensive assemblage of features that are likely to be produced in each of the geomorphic environments. We hope that this atlas will trigger more research on diagnostic features, particularly their morphometry and detailed morphology, their persistence and rates of formation. In this first edition of the atlas we detail the features found on clasts in three geomorphic environments: aeolian, fluvial and weathering. Future editions of the atlas will include chapters on ejecta, micro-impacts, coastal, colluvial, glacial and structural features.

Geomorphic Controls on Floodplain Soil Organic Carbon in the Yukon Flats, Interior Alaska, From Reach to River Basin Scales

NASA Astrophysics Data System (ADS)

Lininger, K. B.; Wohl, E.; Rose, J. R.

2018-03-01

Floodplains accumulate and store organic carbon (OC) and release OC to rivers, but studies of floodplain soil OC come from small rivers or small spatial extents on larger rivers in temperate latitudes. Warming climate is causing substantial change in geomorphic process and OC fluxes in high latitude rivers. We investigate geomorphic controls on floodplain soil OC concentrations in active-layer mineral sediment in the Yukon Flats, interior Alaska. We characterize OC along the Yukon River and four tributaries in relation to geomorphic controls at the river basin, segment, and reach scales. Average OC concentration within floodplain soil is 2.8% (median = 2.2%). Statistical analyses indicate that OC varies among river basins, among planform types along a river depending on the geomorphic unit, and among geomorphic units. OC decreases with sample depth, suggesting that most OC accumulates via autochthonous inputs from floodplain vegetation. Floodplain and river characteristics, such as grain size, soil moisture, planform, migration rate, and riverine DOC concentrations, likely influence differences among rivers. Grain size, soil moisture, and age of surface likely influence differences among geomorphic units. Mean OC concentrations vary more among geomorphic units (wetlands = 5.1% versus bars = 2.0%) than among study rivers (Dall River = 3.8% versus Teedrinjik River = 2.3%), suggesting that reach-scale geomorphic processes more strongly control the spatial distribution of OC than basin-scale processes. Investigating differences at the basin and reach scale is necessary to accurately assess the amount and distribution of floodplain soil OC, as well as the geomorphic controls on OC.

Morphotectonic Index Analysis as an Indicator of Neotectonic Segmentation of the Nicoya Peninsula, Costa Rica

NASA Astrophysics Data System (ADS)

Morrish, S.; Marshall, J. S.

2013-12-01

The Nicoya Peninsula lies within the Costa Rican forearc where the Cocos plate subducts under the Caribbean plate at ~8.5 cm/yr. Rapid plate convergence produces frequent large earthquakes (~50yr recurrence interval) and pronounced crustal deformation (0.1-2.0m/ky uplift). Seven uplifted segments have been identified in previous studies using broad geomorphic surfaces (Hare & Gardner 1984) and late Quaternary marine terraces (Marshall et al. 2010). These surfaces suggest long term net uplift and segmentation of the peninsula in response to contrasting domains of subducting seafloor (EPR, CNS-1, CNS-2). In this study, newer 10m contour digital topographic data (CENIGA- Terra Project) will be used to characterize and delineate this segmentation using morphotectonic analysis of drainage basins and correlation of fluvial terrace/ geomorphic surface elevations. The peninsula has six primary watersheds which drain into the Pacific Ocean; the Río Andamojo, Río Tabaco, Río Nosara, Río Ora, Río Bongo, and Río Ario which range in area from 200 km2 to 350 km2. The trunk rivers follow major lineaments that define morphotectonic segment boundaries and in turn their drainage basins are bisected by them. Morphometric analysis of the lower (1st and 2nd) order drainage basins will provide insight into segmented tectonic uplift and deformation by comparing values of drainage basin asymmetry, stream length gradient, and hypsometry with respect to margin segmentation and subducting seafloor domain. A general geomorphic analysis will be conducted alongside the morphometric analysis to map previously recognized (Morrish et al. 2010) but poorly characterized late Quaternary fluvial terraces. Stream capture and drainage divide migration are common processes throughout the peninsula in response to the ongoing deformation. Identification and characterization of basin piracy throughout the peninsula will provide insight into the history of landscape evolution in response to differential uplift. Conducting this morphotectonic analysis of the Nicoya Peninsula will provide further constraints on rates of segment uplift, location of segment boundaries, and advance the understanding of the long term deformation of the region in relation to subduction.

Identification of Suitable Water Harvesting Zones Based on Geomorphic Resources for Drought Areas: A Case Study of Una District, Himachal Pradesh, India.

NASA Astrophysics Data System (ADS)

Prakasam, D. C., Jr.; Zaman, B.

2014-12-01

Water is one of the most vital natural resource and its availability and quality determine ecosystem productivity, both for agricultural and natural systems. Una district is one of the major potential agricultural districts in Himachal Pradesh, India. More than 70% of the population of this district is engaged in agriculture and allied sectors and major crops grown are maize, wheat, rice, sugarcane, pulses and vegetables. The region faces drought every year and about 90 per cent of the area is water stressed. This has resulted in crop loss and shortage of food and fodder. The sources of drinking water, small ponds and bowlies dry-up during summer season resulting in scarcity of drinking water. Una district receives rainfall during monsoons from June to September and also during non-monsoon period (winter). The annual average rainfall in the area is about 1040 mm with 55 average rainy days. But due to heavy surface run-off the farmers not able to cultivate the crops more than once in a year. Past research indicate that the geomorphology of the Una district might be responsible for such droughts as it controls the surface as well as ground water resources. The research proposes to develop a water stress model for Una district using the geomorphic parameters, water resource and land use land cover data of the study area. Using Survey of India topographical maps (1:50000), the geomorphic parameters are extracted. The spatial layers of these parameters i.e. drainage density, slope, relative relief, ruggedness index, surface water body's frequency are created in GIS. A time series of normalized remotely sensed data of the study area is used for land use land cover classification and analyses. Based on the results from the water stress model, the drought/water stress areas and water harvesting zones are identified and documented. The results of this research will help the general population in resolving the drinking water problem to a certain extent and also the cultivators to water the crops more than twice per year which might increase the crop yield in Una district.

The geological history of Northeast Syrtis Major, Mars

NASA Astrophysics Data System (ADS)

Bramble, Michael S.; Mustard, John F.; Salvatore, Mark R.

2017-09-01

As inferred from orbital spectroscopic data, Northeast Syrtis Major bears considerable mineral diversity that spans the Noachian-Hesperian boundary despite its small geographic area. In this study we use observations from the High Resolution Imaging Science Experiment, supplemented with Context Camera imagery, to characterize and map the lateral extent of geomorphic units in Northeast Syrtis Major, and constrain the geomorphic context of the orbital-identified mineral signatures. Using recent observations, we confirm previous mineralogy identified with the Compact Reconnaissance Imaging Spectrometer for Mars, and greatly extend the lateral extent of visible to near-infrared investigation utilizing the greater coverage. Analysis of Thermal Emission Imaging System observations reveals further physical properties and distribution of the geomorphic units. The stratigraphy, which spans the Noachian-Hesperian boundary, displays significant morphological heterogeneity at the decameter scale, but it is unifiable under five distinct geomorphic units. Our paired morphological and mineralogical analysis allows us to construct a detailed geological history of Northeast Syrtis Major. Several geological events that occurred in Northeast Syrtis Major-including the formation of the post-Isidis crust, the emplacement of an olivine-rich unit, the formation of sulfate minerals, and the emplacement of the Syrtis Major Volcanics-can be related to regional and global processes constraining the local chronology. Other mineralogical indicators, particularly the formation of Al-phyllosilicates, are difficult to place in the temporal sequence. They are observed in isolated patches on the post-Isidis crust, not as a distinct stratigraphic unit as observed elsewhere in Nili Fossae, suggesting their formation via isolated leaching or through alteration of initial compositional heterogeneities within the crust. Exposures of an olivine-rich unit are intermittently observed to form quasi-circular landforms, suggestive of emplacement in circular depressions, which may indicate a period of cratering between the formation of the Isidis basin and the deposition of the olivine-rich unit. We identify and discuss intriguing large linear features of the olivine-rich unit, reminiscent of dyke-fed volcanism, that have raised bounding ridges suggestive of contact metamorphism with the crust. We compile, review, and discuss many of the outstanding questions and running hypotheses relevant to our mapping area. A synthesis of our geomorphic mapping with recent literature reveals a well-defined geological history with extensive aqueous activity at Northeast Syrtis Major that is amassed in a stratigraphic sequence spanning a time likely greater than 250 million years of geological history. Our geomorphic and spectral analyses confirm that Northeast Syrtis Major exhibits considerable geomorphic and mineralogic diversity within a relatively small geographic area that is representative of the geologic processes occurring throughout the broader Nili Fossae region during the Noachian and Hesperian. Northeast Syrtis Major adds to this sequence by exposing the diverse environmental history of this region as observed through the presence of alteration minerals not present in this fidelity or proximity elsewhere in Nili Fossae.

GEOMORPHIC CONTROLS ON MEADOW ECOSYSTEMS – INSIGHTS INTO LOCAL PROCESSES USING NEAR-SURFACE SEISMIC TECHNIQUES AND GROUND PENETRATING RADAR

EPA Science Inventory

Geomorphic controls on riparian meadows in the Central Great Basin of Nevada are an important aspect in determining the formation of and planning the management of these systems. The current hypothesis is that both alluvial fan sediment and faulted bedrock steps interact to cont...

Application of Terrestrial Geomorphic Threshold Theory to the Analysis of Small Channels on Mars

NASA Technical Reports Server (NTRS)

Rosenshein, E. B.; Greeley, R.; Arrowsmith, J. R.

2001-01-01

New terrestrial work on the geomorphic thresholds for channel initiation use the drainage area above a channel head vs. the slope at the channel head to delineate surface process types. This method has been used to characterize martian landscapes. Additional information is contained in the original extended abstract.

Seismotectonic, structural, volcanologic, and geomorphic study of New Zealand; indigenous forest assessment in New Zealand; mapping, land use and environmental studies in New Zealand, volume 3

NASA Technical Reports Server (NTRS)

Probine, M. C.; Suggate, R. P.; Mcgreevy, M. G.; Stirling, I. F. (Principal Investigator)

1977-01-01

The author has identified the following significant results. The present resolution of LANDSAT precludes its use for topographic mapping at scales larger than 1:250,000. Encouraging potential was displayed for environmental and land use studies at scales up to 1:100,000.

Mapping, Monitoring, and Modeling Geomorphic Processes to Identify Sources of Anthropogenic Sediment Pollution in West Maui, Hawai'i

NASA Astrophysics Data System (ADS)

Cerovski-Darriau, C.; Stock, J. D.; Winans, W. R.

2016-12-01

Episodic storm runoff in West Maui (Hawai'i) brings plumes of terrestrially-sourced fine sediment to the nearshore ocean environment, degrading coral reef ecosystems. The sediment pollution sources were largely unknown, though suspected to be due to modern human disturbance of the landscape, and initially assumed to be from visibly obvious exposed soil on agricultural fields and unimproved roads. To determine the sediment sources and estimate a sediment budget for the West Maui watersheds, we mapped the geomorphic processes in the field and from DEMs and orthoimagery, monitored erosion rates in the field, and modeled the sediment flux using the mapped processes and corresponding rates. We found the primary source of fine sands, silts and clays to be previously unidentified fill terraces along the stream bed. These terraces, formed during legacy agricultural activity, are the banks along 40-70% of the streams where the channels intersect human-modified landscapes. Monitoring over the last year shows that a few storms erode the fill terraces 10-20 mm annually, contributing up to 100s of tonnes of sediment per catchment. Compared to the average long-term, geologic erosion rate of 0.03 mm/yr, these fill terraces alone increase the suspended sediment flux to the coral reefs by 50-90%. Stakeholders can use our resulting geomorphic process map and sediment budget to inform the location and type of mitigation effort needed to limit terrestrial sediment pollution. We compare our mapping, monitoring, and modeling (M3) approach to NOAA's OpenNSPECT model. OpenNSPECT uses empirical hydrologic and soil erosion models paired with land cover data to compare the spatially distributed sediment yield from different land-use scenarios. We determine the relative effectiveness of calculating a baseline watershed sediment yield from each approach, and the utility of calibrating OpenNSEPCT with M3 results to better forecast future sediment yields from land-use or climate change scenarios.

A Geomorphic Analysis of Floodplain Lakes along the Embanked Lower Mississippi River for Managing Hydrologic Connectivity

NASA Astrophysics Data System (ADS)

Hudson, Paul; Boot, Dax; Sounny-Slitinne, M. Anwar; Kristensen, Kristiaan

2015-04-01

A Geomorphic Analysis of Floodplain Lakes along the Embanked Lower Mississippi River for Managing Hydrologic Connectivity Floodplain lakes are vital to the environmental integrity of lowland rivers. Embankment by levees (dikes) for flood control greatly reduces the size of lowland floodplains and is detrimental to the quality and functioning of floodplain water bodies, presenting a challenge to government agencies charged with environmental management. The embanked floodplain of the Lower Mississippi River is an enormous surface which includes a variety of lake types formed by geomorphic and anthropogenic processes. While much is known about the channel and hydrologic regime, very little is known about the physical structure and functioning of the embanked floodplain of the lower Mississippi. Importantly, management agencies do not have an inventory of the basic characteristics (e.g., type, frequency, location, size, shape) of water bodies within the lower Mississippi embanked floodplain. An analysis of lakes along the Lower Mississippi River embanked floodplain is performed by utilizing the National Hydrographic Dataset (NHD) from the U.S. Geological Survey, a LiDAR digital elevation model (DEM), as well as streamflow data from the USGS. The vector NHD data includes every official mapped water body (blue line polygons) on USGS topographic maps at scales of 1:100,000 and 1:24,000. Collectively, we identify thousands of discreet water bodies within the embanked floodplain. Utilizing planimetric properties the water bodies were classified into the following lake types: cutoffs (neck and chute), sloughs, crevasse (scour), local drainage (topographic), and borrow pits. The data is then statistically analyzed to examine significant differences in the spatial variability in lake types along the entire lower Mississippi embanked floodplain in association with geomorphic divisions and hydrologic regime. The total embanked floodplain area of the LMR is 7,303 km2,. The total area of floodplain lakes within the embanked floodplain is 382 km2, or 5.2% of the embanked floodplain surface area. Considerable variability in embanked floodplain area along the lower Mississippi, however, results in spatial variability in the frequency of specific lake types. Meander cutoff lakes represent the largest proportion of lake area, at 49%, with approximately half of this area comprised of artificial cutoff lakes. The next largest class of lakes are borrow pit lakes (at 16%), which are anthropogenic water bodies created for the process of levee (dike) construction and maintenance, but which represent valuable environmental habitat. Meander cutoff lakes are especially dominant in the upper reaches of the Lower Mississippi and diminish moving downstream, where the area of embanked floodplain also decreases. Interestingly, anthropogenic lakes (borrow pits) become increasingly prevalent further downstream and dominate over natural formed lakes. The location of lake types along the Lower Mississippi does not correspond with recent historic geomorphic and hydrologic activity. The highest frequency of meander cutoff and crevasse lakes are not located within floodplain sections which historically had the highest rates of lateral migration (m/yr) and flooding (duration). Although overbank hydrologic connectivity varies along the river, it does not vary necessarily where it would be most advantageous to the connectivity of specific types of lakes. The research results provide government agencies with a spatial inventory and methodological approach to improve the management of floodplain water bodies for sustaining valuable aquatic habitat, whether by artificially restricting or enhancing hydrologic connectivity. Key words: floodplain lakes, fluvial geomorphology, hydrologic connectivity, anthropogenic impacts, Lower Mississippi River

Comparing long-term geomorphic model outcomes with sediment archives highlights the need for high-resolution Holocene land cover reconstructions

NASA Astrophysics Data System (ADS)

De Brue, Hanne; Verstraeten, Gert

2013-04-01

During the last decade, several global land cover reconstructions have been produced that enable to quantify human impact on the landscape since the introduction of agriculture. Application of these land cover maps in geomorphic models potentially allows to estimate the anthropogenic impact on sediment fluxes and thus to reconstruct changes in landscape morphology through time. However, current land cover reconstructions face some drawbacks. First of all, their low spatial resolution (i.e. 5 arc-minutes at best) questions their use in geomorphic models, as sub-catchment vegetation patterns play an important role in sediment dynamics. Existing global land cover reconstructions also do not differentiate the typology of human impact (cropland, grazing land, disturbed forests), although the susceptibility of different anthropogenic land uses towards erosion varies greatly. Finally, the various land cover reconstructions differ significantly regarding the estimated intensity of human impact for the preindustrial period. In this study, we assessed the performance of a spatially distributed erosion and sediment redistribution model that operates at high resolution (100 m) to the quality and spatial resolution of input land cover maps. This was done through a comparison of two sets of model runs. Firstly, low-resolution land cover (expressed as percentage of non-natural vegetation) maps were resampled to a spatial resolution of 100 m without differentiation of non-natural vegetation types. For the second set of model runs, estimated non-natural vegetation was differentiated in areas of cropland and grassland, and spatially allocated to a high-resolution grid (100 m) using a logistic model that relates contemporary land cover classes to slope, soil characteristics, landforms and distance to rivers. For both land cover maps, different scenarios for the ratio between cropland and grassland were simulated. Analyses were performed for several time periods throughout the Holocene, for the Scheldt River Basin (19,000 km2) in Belgium and northern France. Results indicate that low-resolution land cover information, regardless of the considered cropland/grassland ratio, leads to largely overestimated sediment fluxes when compared to field-based sediment budgets. Allocation of land cover to a higher spatial resolution yields far better results. Variations in model outcomes are related to differences in landscape connectivity between allocated and non-allocated land cover. These results point towards the need for higher-resolution land cover maps that incorporate the patchiness of vegetation at relevant scales regarding geomorphic processes. Also, model results with allocated and non-allocated land cover maps differ greatly for different cropland/grassland ratios. This indicates that there is not only a need for land cover reconstructions at high spatial resolution, but also that differentiation between cropland and grassland is essential for accurate geomorphic modeling. Further improvements in land cover reconstructions are thus needed before reliable quantitative estimates of anthropogenic impact on soil profiles and sediment redistribution can be simulated at continental scales. Detailed historic sediment budgets can provide an important tool not only for validating but also for reconstructing land cover histories.

Mapping coastal morphodynamics with geospatial techniques, Cape Henry, Virginia, USA

NASA Astrophysics Data System (ADS)

Allen, Thomas R.; Oertel, George F.; Gares, Paul A.

2012-01-01

The advent and proliferation of digital terrain technologies have spawned concomitant advances in coastal geomorphology. Airborne topographic Light Detection and Ranging (LiDAR) has stimulated a renaissance in coastal mapping, and field-based mapping techniques have benefitted from improvements in real-time kinematic (RTK) Global Positioning System (GPS). Varied methodologies for mapping suggest a need to match geospatial products to geomorphic forms and processes, a task that should consider product and process ontologies from each perspective. Towards such synthesis, coastal morphodynamics on a cuspate foreland are reconstructed using spatial analysis. Sequential beach ridge and swale topography are mapped using photogrammetric spot heights and airborne LiDAR data and integrated with digital bathymetry and large-scale vector shoreline data. Isobaths from bathymetric charts were digitized to determine slope and toe depth of the modern shoreface and a reconstructed three-dimensional antecedent shoreface. Triangulated irregular networks were created for the subaerial cape and subaqueous shoreface models of the cape beach ridges and sets for volumetric analyses. Results provide estimates of relative age and progradation rate and corroborate other paleogeologic sea-level rise data from the region. Swale height elevations and other measurements quantifiable in these data provide several parameters suitable for studying coastal geomorphic evolution. Mapped paleoshorelines and volumes suggest the Virginia Beach coastal compartment is related to embryonic spit development from a late Holocene shoreline located some 5 km east of the current beach.

Geology of Holden Crater and the Holden and Ladon Multi-Ring Impact Basins, Margaritifer Terra, Mars

NASA Technical Reports Server (NTRS)

Irwin, R. P., III; Grant, J. A.

2008-01-01

Geologic mapping at 1:500K scale of Mars quads 15s027, 20s027, 25s027, and 25s032 (Fig. 1) is in progress to constrain the geologic and geomorphic history of southwestern Margaritifer Terra. This work builds on earlier maps at 1:5M [1] and 1:15M scales [2], recent to concurrent 1:500Kscale mapping of adjacent areas to the east [3-5], and studies of drainage basin evolution along the Uzboi-Ladon-M (ULM; the third valley in the sequence has no formal name) Valles basin overflow system and nearby watersheds [6-9]. Two of the six landing sites under consideration for the Mars Science Laboratory rover are in this map area, targeting finely layered, phyllosilicate-rich strata and alluvial fans in Holden crater [10-12] (26degS, 34degW, 150 km diameter) or deposits southeast of a likely delta in Eberswalde crater [13-16] (24degS, 33degW, 50 km in diameter). Diverse processes including larger and smaller impacts, a wide range in fluvial activity, and local to regional structural influences have all affected the surface morphology.

Geologic applications of thermal-inertia mapping from satellite. [Powder River, Wyoming; Cubeza Prieta, Arizona, and Yellowstone National Park

NASA Technical Reports Server (NTRS)

Offield, T. W. (Principal Investigator); Watson, K.; Hummer-Miller, S.

1981-01-01

In the Powder River Basin, Wyo., narrow geologic units having thermal inertias which contrast with their surroundings can be discriminated in optimal images. A few subtle thermal inertia anomalies coincide with areas of helium leakage believed to be associated with deep oil and gas concentrations. The most important results involved delineation of tectonic framework elements some of which were not previously recognized. Thermal and thermal inertia images also permit mapping of geomorphic textural domains. A thermal lineament appears to reveal a basement discontinuity which involves the Homestake Mine in the Black Hill, a zone of Tertiary igneous activity and facies control in oil producing horizons. Applications of these data to the Cabeza Prieta, Ariz., area illustrate their potential for igneous rock type discrimination. Extension to Yellowstone National Park resulted in the detection of additional structural information but surface hydrothermal features could not be distinguished with any confidence. A thermal inertia mapping algorithm, a fast and accurate image registration technique, and an efficient topographic slope and elevation correction method were developed.

Basin-scale characterization of river hydromorphology by map derived information: A case study on the Red River (Sông Hông), Vietnam

NASA Astrophysics Data System (ADS)

Schmitt, R. J.; Bizzi, S.; Castelletti, A.

2012-12-01

The understanding of river hydromorphological processes has been recognized in the last decades as a priority of modern catchment management, since fluvial geomorphic processes shape physical habitat, affect river infrastructures and influence freshwater ecological processes. Characterization of river hydromorphological features is commonly location specific and highly demanding in terms of field-works, resource and expertise required. Therefore, its routine application at regional or national scales, although an urgent need of catchment management, is infeasible at present. Recently available high-resolution data, such as DEM or LIDAR, opens up novel potential for basin-wide analysis of fluvial processes at limited effort and cost. Specifically, in this study we assess the feasibility of characterizing river hydromorphology from specific map derived geomorphic controls namely: channel gradient, bankfull flow, specific stream power, and degree of channel confinement. The river network, extracted from a digital elevation model and validated with available network shape-files and optical satellite imagery, available flow gauging stations and GIS processing allow producing continuous values of geomorphic drivers defined over given length segments at catchment or regional scales. This generic framework was applied to the Red River (Sông Hông) basin, the second largest basin (87,800 km2) in Vietnam. Besides its economic importance, the river since few years is experiencing severe river bed incisions due to the building of new dams in the upstream part of the catchment and sand mining in the surrounding of the capital city Hanoi. In this context, characterized by an high developing rate, current efforts to increase water productivity by infrastructure and management measures require a thorough understanding of fluvial system and, in particular, of the basin-wide river hydromorphology. The framework proposed has allowed producing high-dimensional samples of spatially distributed geomorphic drivers at catchment scale for the Red River basin. This novel dataset has been then analysed using self-organizing maps (SOM) an artificial neural network model that is capable of learning from complex, multidimensional data without specification of what the outputs should be, and of generating a nonlinear classification of visually decipherable clusters. The use of the above framework allowed to analyze the spatial distribution of geomorphic features at catchment scale, reviling patterns of similarities and dissimilarities within the catchment and allowing classification of river reaches characterized by similar geomorphic drivers and then likely (but still to be validated) fluvial processes. The paper proposes an innovative and promising technique to produce hydromorphological classifications at catchment scale opening the way towards regional or national scale hydromorphological assessments through automatic GIS and statistical procedures with moderate effort, an urgent requirement of modern catchment management.

Recognition of fiducial surfaces in lidar surveys of coastal topography

USGS Publications Warehouse

Brock, J.C.; Sallenger, A.H.; Krabill, W.B.; Swift, R.N.; Wright, C.W.

2001-01-01

A new method for the recognition and mapping of surfaces in coastal landscapes that provide accurate and low variability topographic measurements with respect to airborne lidar surveys is described and demonstrated in this paper. Such surfaces are herein termed "fiducial" because they can represent reference baseline morphology in Studies of coastal change due to natural or anthropogenic causes. Non-fiducial surfaces may also be identified in each separate lidar survey to be used in a given geomorphic change analysis. Sites that are non-fiducial in either or both lidar surveys that bracket the time period under investigation may be excluded from consideration in subsequent calculations of survey-to-survey elevation differences to eliminate spurious indications of landscape change. This new analysis method, or lidar fiducial surface recognition (LFSR) algorithm, is intended to more fully enable the non-ambiguous Use of topographic lidar in a range of coastal investigations. The LFSR algorithm may be widely applied, because it is based solely on the information inherent in the USGS/NASA/NOAA airborne topographic lidar coverage that exists for most of the contiguous U.S. coastline.

Geomorphologic Analysis of Drainage Basins in Damavand Volcano Cone, Iran

NASA Astrophysics Data System (ADS)

Zareinejad, M.

2011-12-01

Damavand volcanic cone is located in the center of the Alborz chain, in the southern Caspian Sea in Iran. Damavand is a dormant volcano in Iran. It is not only the country's highest peak but also the highest mountain on the Middle East; its elevation is 5619 m. The main purpose of this paper is recognition and appraisement of drainage basins in Damavand cone from geomorphic point of view. Water causes erosion in nature in different forms and creates diverse forms on the earth surface depending on the manner of its appearance in nature. Although water is itself a former factor, it flows under morphological effect of earth surface. The difference of earth surface topography and as a result water movement on it, cause the formation of sub-basins. Identification of region drainage basins is considered as one of the requirements for Damavand cone morphometric. Thereupon, five drainage basins were identified in this research by relying on main criteria including topographic contours with 10 m intervals, drainage system, DEM map, slope map, aspect map and satellite images. (Fig 1) Area, perimeter, height classification for classifying morphological landforms in different levels, hypsometric calculations, drainage density, etc. were then calculated by using ArcGIS software. (Table 1) Damavand cone, with a height more than 5,000 meters from the sea surface, has very hard pass slopes and our purpose in this paper is to identify the effect of drainage basins conditions in the region on erosion and the formation of morphological landforms by using SPOT, ASTER, satellite images as well as papering of data in GIS environment.

Prediction of Ba, Mn and Zn for tropical soils using iron oxides and magnetic susceptibility

NASA Astrophysics Data System (ADS)

Marques Júnior, José; Arantes Camargo, Livia; Reynaldo Ferracciú Alleoni, Luís; Tadeu Pereira, Gener; De Bortoli Teixeira, Daniel; Santos Rabelo de Souza Bahia, Angelica

2017-04-01

Agricultural activity is an important source of potentially toxic elements (PTEs) in soil worldwide but particularly in heavily farmed areas. Spatial distribution characterization of PTE contents in farming areas is crucial to assess further environmental impacts caused by soil contamination. Designing prediction models become quite useful to characterize the spatial variability of continuous variables, as it allows prediction of soil attributes that might be difficult to attain in a large number of samples through conventional methods. This study aimed to evaluate, in three geomorphic surfaces of Oxisols, the capacity for predicting PTEs (Ba, Mn, Zn) and their spatial variability using iron oxides and magnetic susceptibility (MS). Soil samples were collected from three geomorphic surfaces and analyzed for chemical, physical, mineralogical properties, as well as magnetic susceptibility (MS). PTE prediction models were calibrated by multiple linear regression (MLR). MLR calibration accuracy was evaluated using the coefficient of determination (R2). PTE spatial distribution maps were built using the values calculated by the calibrated models that reached the best accuracy by means of geostatistics. The high correlations between the attributes clay, MS, hematite (Hm), iron oxides extracted by sodium dithionite-citrate-bicarbonate (Fed), and iron oxides extracted using acid ammonium oxalate (Feo) with the elements Ba, Mn, and Zn enabled them to be selected as predictors for PTEs. Stepwise multiple linear regression showed that MS and Fed were the best PTE predictors individually, as they promoted no significant increase in R2 when two or more attributes were considered together. The MS-calibrated models for Ba, Mn, and Zn prediction exhibited R2 values of 0.88, 0.66, and 0.55, respectively. These are promising results since MS is a fast, cheap, and non-destructive tool, allowing the prediction of a large number of samples, which in turn enables detailed mapping of large areas. MS predicted values enabled the characterization and the understanding of spatial variability of the studied PTEs.

Prediction of Ba, Co and Ni for tropical soils using diffuse reflectance spectroscopy and X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Arantes Camargo, Livia; Marques Júnior, José; Reynaldo Ferracciú Alleoni, Luís; Tadeu Pereira, Gener; De Bortoli Teixeira, Daniel; Santos Rabelo de Souza Bahia, Angélica

2017-04-01

Environmental impact assessments may be assisted by spatial characterization of potentially toxic elements (PTEs). Diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF) are rapid, non-destructive, low-cost, prediction tools for a simultaneous characterization of different soil attributes. Although low concentrations of PTEs might preclude the observation of spectral features, their contents can be predicted using spectroscopy by exploring the existing relationship between the PTEs and soil attributes with spectral features. This study aimed to evaluate, in three geomorphic surfaces of Oxisols, the capacity for predicting PTEs (Ba, Co, and Ni) and their spatial variability by means of diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF). For that, soil samples were collected from three geomorphic surfaces and analyzed for chemical, physical, and mineralogical properties, and then analyzed in DRS (visible + near infrared - VIS+NIR and medium infrared - MIR) and XRF equipment. PTE prediction models were calibrated using partial least squares regression (PLSR). PTE spatial distribution maps were built using the values calculated by the calibrated models that reached the best accuracy using geostatistics. PTE prediction models were satisfactorily calibrated using MIR DRS for Ba, and Co (residual prediction deviation - RPD > 3.0), Vis DRS for Ni (RPD > 2.0) and FRX for all the studied PTEs (RPD > 1.8). DRS- and XRF-predicted values allowed the characterization and the understanding of spatial variability of the studied PTEs.

Drainage lineaments in late Quaternary sediments, Ascension and East Baton Rouge Parishes, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birdseye, R.U.; Christians, G.L.; Olson, J.L.

1988-09-01

Analysis of conventional aerial photographs, NHAP imagery, and topographic maps covering Ascension and East Baton Rouge Parishes in southeastern Louisiana reveals fine-textured parallel sets of drainage lineaments and numerous fluvial anomalies. Linear physiographic features include stream channels, natural levees, stream valleys, rectangular drainage patterns, and terrace scarps. Late Pleistocene and Holocene surfaces are involved, but only small drainages are affected and no such control is exerted on the Mississippi river. Most lineaments show preferred northeast and northwest trends. Orientations of mapped joint systems are similar to lineament orientations, which suggests that trends of physiographic lineaments are controlled by underlying structure.more » Several surface faults are mapped in the northern portion of the region, all of which strike essentially east-west. Salt domes are located in the subsurface to the south; however, they have no geomorphic expression and do not seem to be associated with the lineaments. Therefore, joints rather than faults or salt diapirs are a likely structural control. Joints may provide paths of weakness along which surface drainage might develop preferentially. Thus, joints probably exert an important control on the geomorphology of the region. The joint pattern appears to be related to the local distribution of the Mesozoic and Cenozoic strata, and may result from regional subsidence due to the thick accumulation of deltaic sediments. Conclusive subsurface data are currently unavailable, and shallow seismic surveys in the future may strengthen the case for an interpretation of structural control of drainage.« less

Why do sand furrow distributions vary in the North Polar latitudes on Mars?

NASA Astrophysics Data System (ADS)

Bourke, Mary; McGaley-Towle, Zoe

2014-05-01

Sand dunes on Mars display geomorphic evidence of an active and dynamic sediment flux. Barchan dunes migrate, ripples move and the slipface morphology changes annually. Aeolian sediment transport is seasonally constrained and linked to cryogenic processes. Sand furrows are geomorphic features that are eroded into the surface of dunes. They form during sublimation of the seasonal carbon dioxide deposit which moves gas and sand through vents in the ice (cryo-venting) (Bourke, 2013). They are visible on the surface of dunes using the highest resolution images available for Mars. Previous work has noted that the distribution of furrows varies spatially both on individual dunes and at different Polar locations. Here we report on the preliminary findings of a mapping project that seeks to confirm this previous qualitative observation. In addition, we aim to explain the observed spatial and temporal variation in sand furrows on North Polar dunes. Ten polar sites that reflect a latitudinal range of 9.5º are being analysed. The HiRISE images were acquired between 16/2/2012 and 31/05/2012, over a period of 105 Earth days or 102 Sols. We have completed mapping of 1711 sand furrows in an 84 km2 area of sand dunes, i.e. at four of the ten sites. The data confirm that there is variability in the distribution of sand furrows in the Polar Region. While data from all ten sites will be required to fully test the assertion of a latitudinal control, it is worth noting that the two most northerly sites have a significantly higher density of furrows compared to the two lower latitude sites. As the seasonal ice thickness is known to increases pole-ward on Mars, our data suggest that effective furrow formation may be linked to ice deposit thickness. In particular, it suggests that a threshold in ice thickness must be crossed in order for effective cryo-venting to occur. Bourke, M.C., 2013. Sand Furrows: A new surface feature on Martian dunes, EGU, EGU2013-11859, Vienna.

Analysis of Landslide Kinematics using Multi-temporal UAV Imagery, La Honda, California

NASA Astrophysics Data System (ADS)

Carey, J.; Pickering, A.; Prentice, C. S.; Pinter, N.; DeLong, S.

2017-12-01

High-resolution topographic data are vital to studies of earth-surface processes. The combination of unmanned aerial vehicle (UAV) photography and structure-from-motion (SfM) digital photogrammetry provide a quickly deployable and cost-effective method for monitoring geomorphic change and landscape evolution. We acquired imagery of an active landslide in La Honda, California using a GPS-enabled quadcopter UAV with a 12.4 megapixel camera. Deep-seated landslides were previously documented in this region during the winter of 1997-98, with movement recurring and the landslide expanding during the winters of 2004-05 and 2005-06. This study documents the kinematics of a new and separate landslide immediately adjacent to the previous ones, throughout the winter of 2016-17. The roughly triangular-shaped, deep-seated landslide covers an area of approximately 10,000 m2. The area is underlain by SW dipping late Miocene to Pliocene sandstones and mudstones. A 3 m high head scarp stretches along the northeast portion of the slide for approximately 100 m. Internally, the direction of movement is towards the southwest, with two prominent NW-SE striking extensional grabens and numerous tension cracks across the landslide body. Here we calculate displaced landslide volumes and surface displacements from multi-temporal UAV surveys. Photogrammetric reconstruction of UAV/SfM-derived point clouds allowed creation of six digital elevation models (DEMs) with spatial resolutions ranging from 3 to 15 cm per pixel. We derived displacement magnitude, direction and rate by comparing multiple generations of DEMs and orthophotos, and estimated displaced volumes by differencing subsequent DEMs. We then correlated displacements with total rainfall and rainfall intensity measurements. Detailed geomorphic maps identify major landslide features, documenting dominant surface processes. Additionally, we compare the accuracy of the UAV/SfM-derived DEM with a DEM sourced from a synchronous terrestrial lidar survey. Conservative measurements yield 5.4 m of maximum horizontal displacement across the central portion of the slide. This study demonstrates the ability of the UAV/SfM workflow to map and monitor active mass-wasting processes in regions where landslides pose a direct threat to the surrounding community.

Features and dimensions of the Hayward Fault Zone in the Strawberry and Blackberry Creek Area, Berkeley, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, P.L.

1995-03-01

This report presents an examination of the geometry of the Hayward fault adjacent to the Lawrence Berkeley Laboratory and University of California campuses in central Berkeley. The fault crosses inside the eastern border of the UC campus. Most subtle geomorphic (landform) expressions of the fault have been removed by development and by the natural processes of landsliding and erosion. Some clear expressions of the fault remain however, and these are key to mapping the main trace through the campus area. In addition, original geomorphic evidence of the fault`s location was recovered from large scale mapping of the site dating frommore » 1873 to 1897. Before construction obscured and removed natural landforms, the fault was expressed by a linear, northwest-tending zone of fault-related geomorphic features. There existed well-defined and subtle stream offsets and beheaded channels, fault scarps, and a prominent ``shutter ridge``. To improve our confidence in fault locations interpreted from landforms, we referred to clear fault exposures revealed in trenching, revealed during the construction of the Foothill Housing Complex, and revealed along the length of the Lawson Adit mining tunnel. Also utilized were the locations of offset cultural features. At several locations across the study area, distress features in buildings and streets have been used to precisely locate the fault. Recent published mapping of the fault (Lienkaemper, 1992) was principally used for reference to evidence of the fault`s location to the northwest and southeast of Lawrence Berkeley Laboratory.« less

Mapping Prehistoric, Historic, and Channel Sediment Distribution, South Fork Noyo River: A Tool For Understanding Sources, Storage, and Transport

Treesearch

Rich D. Koehler; Keith I. Kelson; Graham Matthews; K.H. Kang; Andrew D. Barron

2007-01-01

The South Fork Noyo River (SFNR) watershed in coastal northern California contains large volumes of historic sediment that were delivered to channels in response to past logging operations. This sediment presently is stored beneath historic terraces and in present-day channels. We conducted geomorphic mapping on the SFNR valley floor to assess the volume and location...

Application of ground-penetrating radar imagery for three-dimensional visualisation of near-surface structures in ice-rich permafrost, Barrow, Alaska

USGS Publications Warehouse

Munroe, Jeffrey S.; Doolittle, James A.; Kanevskiy, Mikhail; Hinkel, Kenneth M.; Nelson, Frederick E.; Jones, Benjamin M.; Shur, Yuri; Kimble, John M.

2007-01-01

Three-dimensional ground-penetrating radar (3D GPR) was used to investigate the subsurface structure of ice-wedge polygons and other features of the frozen active layer and near-surface permafrost near Barrow, Alaska. Surveys were conducted at three sites located on landscapes of different geomorphic age. At each site, sediment cores were collected and characterised to aid interpretation of GPR data. At two sites, 3D GPR was able to delineate subsurface ice-wedge networks with high fidelity. Three-dimensional GPR data also revealed a fundamental difference in ice-wedge morphology between these two sites that is consistent with differences in landscape age. At a third site, the combination of two-dimensional and 3D GPR revealed the location of an active frost boil with ataxitic cryostructure. When supplemented by analysis of soil cores, 3D GPR offers considerable potential for imaging, interpreting and 3D mapping of near-surface soil and ice structures in permafrost environments.

Using Geomorphic Change Detection to Understand Restoration Project Success Relative to Stream Size

NASA Astrophysics Data System (ADS)

Yeager, A.; Segura, C.

2017-12-01

Large wood (LW) jams have long been utilized as a stream restoration strategy to create fish habitat, with a strong focus on Coho salmon in the Pacific Northwest. These projects continue to be implemented despite limited understanding of their success in streams of different size. In this study, we assessed the changes triggered by LW introductions in 10 alluvial plane bed reaches with varying drainage areas (3.9-22 km²) and bankfull widths (6.4-14.7 m) in one Oregon Coast Range basin. In this basin, LW was added in an effort to improve winter rearing habitat for Coho salmon. We used detailed topographic mapping (0.5 m² resolution) to describe the local stream and floodplain geometry. Pebble counts were used to monitor changes in average substrate size after the LW addition. Field surveys were conducted immediately after the LW were installed, in the summer of 2016, and one year after installation, in the summer of 2017. We used geomorphic change detection analysis to quantify the amount of scour and deposition at each site along with changes in average bankfull width. Then we determined the relative amount of change among all sites to identify which size stream changed the most. We also modeled fluctuations in water surface elevation at each site, correlating frequency and inundation of the LW with geomorphic changes detected from the topographic surveys. Preliminary results show an increase in channel width and floodplain connectivity at all sites, indicating an increase in off-channel habitat for juvenile Coho salmon. Bankfull widths increased up to 75% in small sites and up to 25% in large sites. Median grain size became coarser in large streams (increased up to 20%), while we saw a similar amount of fining at smaller sites. The overall increase in channel width is compensated by an overall decrease in bed elevation at both large and small sites, suggesting the maintenance of overall geomorphic equilibrium. Further work will include quantifying these geomorphic changes in the context of critical salmon habitat factors. By identifying which size stream changes the most after LW introduction, and linking this change to salmon habitat metrics, we will provide information to aid in optimizing future LW stream restoration efforts that focus on stream reaches likely to experience the greatest increase in fish habitat.

Performance evaluation of CESM in simulating the dust cycle

NASA Astrophysics Data System (ADS)

Parajuli, S. P.; Yang, Z. L.; Kocurek, G.; Lawrence, D. M.

2014-12-01

Mineral dust in the atmosphere has implications for Earth's radiation budget, biogeochemical cycles, hydrological cycles, human health and visibility. Mineral dust is injected into the atmosphere during dust storms when the surface winds are sufficiently strong and the land surface conditions are favorable. Dust storms are very common in specific regions of the world including the Middle East and North Africa (MENA) region, which contains more than 50% of the global dust sources. In this work, we present simulation of the dust cycle under the framework of CESM1.2.2 and evaluate how well the model captures the spatio-temporal characteristics of dust sources, transport and deposition at global scale, especially in dust source regions. We conducted our simulations using two existing erodibility maps (geomorphic and topographic) and a new erodibility map, which is based on the correlation between observed wind and dust. We compare the simulated results with MODIS satellite data, MACC reanalysis data, and AERONET station data. Comparison with MODIS satellite data and MACC reanalysis data shows that all three erodibility maps generally reproduce the spatio-temporal characteristics of dust optical depth globally. However, comparison with AERONET station data shows that the simulated dust optical depth is generally overestimated for all erodibility maps. Results vary greatly by region and scale of observational data. Our results also show that the simulations forced by reanalysis meteorology capture the overall dust cycle more realistically compared to the simulations done using online meteorology.

Root tensile strength assessment of Dryas octopetala L. and implications for its engineering mechanism on lateral moraine slopes (Turtmann Valley, Switzerland)

NASA Astrophysics Data System (ADS)

Eibisch, Katharina; Eichel, Jana; Dikau, Richard

2015-04-01

Geomorphic processes and properties are influenced by vegetation. It has been shown that vegetation cover intercepts precipitation, enhances surface detention and storage, traps sediment and provides additional surface roughness. Plant roots impact the soil in a mechanical and hydrological manner and affect shear strength, infiltration capacity and moisture content. Simultaneously, geomorphic processes disturb the vegetation development. This strong coupling of the geomorphic and ecologic system is investigated in Biogeomorphology. Lateral moraine slopes are characterized by a variety of geomorphic processes, e. g. sheet wash, solifluction and linear erosion. However, some plant species, termed engineer species, possess specific functional traits which allow them to grow under these conditions and also enable them to influence the frequency, magnitude and even nature of geomorphic processes. For lateral moraine slopes, Dryas octopetala L., an alpine dwarf shrub, was identified as a potential engineer species. The engineering mechanism of D. octopetala, based on its morphological (e.g., growth form) and biomechanical (e.g., root strength) traits, yet remains unclear and only little research has been conducted on alpine plant species. The objectives of this study are to fill this gap by (A) quantifying D. octopetala root tensile strength as an important trait considering anchorage in and stabilization of the slope and (B) linking plant traits to the geomorphic process they influence on lateral moraine slopes. D. octopetala traits were studied on a lateral moraine slope in Turtmann glacier forefield, Switzerland. (A) Root strength of single root threads of Dryas octopetala L. were tested using the spring scale method (Schmidt et al., 2001; Hales et al., 2013). Measurement equipment was modified to enable field measurements of roots shortly after excavation. Tensile strength of individual root threads was calculated and statistically analyzed. First results show that Dryas roots appear to be quite strong compared to other alpine species with a mean tensile strength of 22,63 N mm -². (B) On a micro scale, morphological and biomechanical features of above and below-ground biomass were qualitatively studied through field observations on D. octopetala individuals. Findings indicate that D. octopetala's dense cushions, covering many square meters of the moraines surface, traps fine sediment, stores moisture and significantly reduces erosion through wind and water. Furthermore, Dryas is well adapted to rock fall or burial by forming stabilized patches of ground despite steep slope inclinations and strong, episodic surface runoff and creep processes. Anchorage is provided by its strong root, which in all studied cases grew upslope parallel to the moraines surface. Insights from this study allow to relate root tensile strength and other specific plant traits of Dryas octopetala to an engineering mechanism and effect on geomorphic processes on lateral moraine slopes. Knowledge about Dryas as an engineering species may help to understand its biotic influence on the geomorphic system of a lateral moraine and aid in the selection of species for erosion control or rehabilitation of ecosystems, where Dryas is native.

Tundra landform and vegetation productivity trend maps for the Arctic Coastal Plain of northern Alaska

PubMed Central

Lara, Mark J.; Nitze, Ingmar; Grosse, Guido; McGuire, A. David

2018-01-01

Arctic tundra landscapes are composed of a complex mosaic of patterned ground features, varying in soil moisture, vegetation composition, and surface hydrology over small spatial scales (10–100 m). The importance of microtopography and associated geomorphic landforms in influencing ecosystem structure and function is well founded, however, spatial data products describing local to regional scale distribution of patterned ground or polygonal tundra geomorphology are largely unavailable. Thus, our understanding of local impacts on regional scale processes (e.g., carbon dynamics) may be limited. We produced two key spatiotemporal datasets spanning the Arctic Coastal Plain of northern Alaska (~60,000 km2) to evaluate climate-geomorphological controls on arctic tundra productivity change, using (1) a novel 30 m classification of polygonal tundra geomorphology and (2) decadal-trends in surface greenness using the Landsat archive (1999–2014). These datasets can be easily integrated and adapted in an array of local to regional applications such as (1) upscaling plot-level measurements (e.g., carbon/energy fluxes), (2) mapping of soils, vegetation, or permafrost, and/or (3) initializing ecosystem biogeochemistry, hydrology, and/or habitat modeling. PMID:29633984

Tundra landform and vegetation productivity trend maps for the Arctic Coastal Plain of northern Alaska

USGS Publications Warehouse

Lara, Mark J.; Nitze, Ingmar; Grosse, Guido; McGuire, A. David

2018-01-01

Arctic tundra landscapes are composed of a complex mosaic of patterned ground features, varying in soil moisture, vegetation composition, and surface hydrology over small spatial scales (10–100 m). The importance of microtopography and associated geomorphic landforms in influencing ecosystem structure and function is well founded, however, spatial data products describing local to regional scale distribution of patterned ground or polygonal tundra geomorphology are largely unavailable. Thus, our understanding of local impacts on regional scale processes (e.g., carbon dynamics) may be limited. We produced two key spatiotemporal datasets spanning the Arctic Coastal Plain of northern Alaska (~60,000 km2) to evaluate climate-geomorphological controls on arctic tundra productivity change, using (1) a novel 30 m classification of polygonal tundra geomorphology and (2) decadal-trends in surface greenness using the Landsat archive (1999–2014). These datasets can be easily integrated and adapted in an array of local to regional applications such as (1) upscaling plot-level measurements (e.g., carbon/energy fluxes), (2) mapping of soils, vegetation, or permafrost, and/or (3) initializing ecosystem biogeochemistry, hydrology, and/or habitat modeling.

Morphotectonic evolution of Maviboğaz canyon and Suğla polje, SW central Anatolia, Turkey

NASA Astrophysics Data System (ADS)

Doğan, Uğur; Koçyiğit, Ali

2018-04-01

This study focuses on the morphotectonic evolutionary history of two significant geomorphic features, Suğla structural-border polje and Maviboğaz canyon, located within the Suğla-Seydişehir, Akören-Kavakköy, and Bozkır grabens in the central Taurides. Data were obtained by detailed field mapping of faults, rocks, and geomorphic features. Three phases of tectonic deformation were determined. The three erosional surfaces developed, especially in the form of tectonically controlled steps, during Oligocene-early Miocene, middle Miocene, and late Miocene-early Pliocene, sequentially. Southwest- to northeast-trending karstified hanging paleovalleys are present on the high erosional surfaces, which have been attributed to the end of early Miocene and late Miocene. Faulting-induced tectonic movements enabled the formation of Suğla-Seydişehir paleograben in early Miocene. We suggest that the Maviboğaz canyon was formed by captures at the beginning of late Miocene and late Pliocene and by incision in Late Pliocene-Quaternary, depending on the headward erosion of Çarşamba River. Starting from the beginning of Quaternary, a tensional neotectonic regime became prominent and then a series of modern graben-horst structures formed along the reactivated older grabens. One of these is the Suğla-Seydişehir reactivated graben. Suğla structural-border polje developed within the graben. Total visible tectonic subsidence of the polje is 134 m. Underground capture of surface water occurred on the southern slopes of the graben. Waters of Suğla polje are transported intermittently into Konya basin on the surface and into the Mediterranean basin via natural swallow holes. Beach deposits, water marks, cliffs, and notches marking the late Pleistocene lake level (10 m) and two perched corrosion surfaces ( 50 and 22 m) were detected around the polje.

Distribution of Early, Middle, and Late Noachian cratered surfaces in the Martian highlands: Implications for resurfacing events and processes

NASA Astrophysics Data System (ADS)

Irwin, Rossman P.; Tanaka, Kenneth L.; Robbins, Stuart J.

2013-02-01

Most of the geomorphic changes on Mars occurred during the Noachian Period, when the rates of impact crater degradation and valley network incision were highest. Fluvial erosion around the Noachian/Hesperian transition is better constrained than the longer-term landscape evolution throughout the Noachian Period, when the highland intercrater geomorphic surfaces developed. We interpret highland resurfacing events and processes using a new global geologic map of Mars (at 1:20,000,000 scale), a crater data set that is complete down to 1 km in diameter, and Mars Orbiter Laser Altimeter topography. The Early Noachian highland (eNh) unit is nearly saturated with craters of 32-128 km diameter, the Middle Noachian highland (mNh) unit has a resurfacing age of ~4 Ga, and the Late Noachian highland unit (lNh) includes younger composite surfaces of basin fill and partially buried cratered terrain. These units have statistically distinct ages, and their distribution varies with elevation. The eNh unit is concentrated in the high-standing Hellas basin annulus and in highland terrain that was thinly mantled by basin ejecta near 180° longitude. The mNh unit includes most of Arabia Terra, the Argyre vicinity, highland plateau areas between eNh outcrops, and the Thaumasia range. The lNh unit mostly occurs within highland basins. Crater depth/diameter ratios do not vary strongly between the eNh and mNh units, although crater losses to Noachian resurfacing appear greater in lower lying areas. Noachian resurfacing was spatially non-uniform, long-lived, and gravity-driven, more consistent with arid-zone fluvial and aeolian erosion and volcanism than with air fall mantling or mass wasting.

Geologic and mineral and water resources investigations in western Colorado using ERTS-1 data

NASA Technical Reports Server (NTRS)

Knepper, D. H., Jr. (Compiler)

1973-01-01

The author has identified the following significant results. Geologic interpretation of ERTS-1 imagery is dependent on recognition of the distribution, continuity, trend, and geometry of key surface features. In the examination of ERTS-1 imagery, lithology must be interpreted largely from the geomorphic expression of the terrain. ERTS-1 imagery is extremely useful in detecting local structures. Most mapped structures are topographically-expressed. Consequently, ERTS-1 imagery acquired during mid-winter, when the solar illumination angle is low, provides the largest amount of structural information. Stereoscopic analyses of ERTS-1 images significantly aid geologic interpretation. Positive transparencies of ERTS-1 images (1:1,000,000) commonly contain more geologic information than can be adequately annotated during geologic interpretation.

A Bird's-Eye View of Eco-Geomorphology From a Small Unmanned Aircraft System (UAS)

NASA Astrophysics Data System (ADS)

LeClair, A. J.; Hugenholtz, C.

2012-12-01

Physical disturbance regimes play important roles in shaping ecosystems and landscapes; however, our ability to detect disturbance often depends on the method and scale of observation. Here we use a relatively new method in order to detect and map the eco-geomorphic impacts of fossorial mammals in a grassland setting. It is well-known that digging and mound building activity by these animals is a form of biological disturbance that has a number of eco-geomorphic consequences, including: soil formation, hydrology, nutrient cycling, and succession. All these processes contribute to landscape heterogeneity and often increase local micro-topographic variations through mound formation. Most studies that have examined the eco-geomorphic role of fossorial mammals have been limited to observations using traditional field-based methods. While this has yielded important data about the localized effects, the cumulative, landscape-level impacts of such small-scale disturbance events are still largely unknown. While fossorial mammals such as pocket gophers (family Geomyidae) are assumed to be ubiquitous in the environments in which they occur, the small size of individual mounds has meant that mapping their biological footprint using traditional methods has been extremely difficult. Individual mounds disappear in the pixels of conventional remote sensing imagery, while their spatial distribution makes it impractical to study them beyond the plot scale. However, recent advances in both low cost, high-resolution digital cameras, and unmanned aerial systems (UAS), have made it possible to acquire landscape-level data that matches the scale of their disturbance, thus potentially bridging the gap between ground-based field methods and traditional remote sensing imagery. In this study we used UAS-acquired, sub-decimeter resolution imagery to map and quantify the extent of fossorial mammal disturbance in a 4 km2 area of the Great Sand Hills - a stabilized dune field in southwestern Saskatchewan, Canada. This area is densely populated by both the northern pocket gopher (Thomomys talpoides) and the thirteen-lined ground squirrel (Ictidomys tridecemlineatus), both of which are active throughout the growing season. Mounds of bare sand occur both singly, and in larger, clustered networks. Older mounds are darker due to higher vegetation cover and litter accumulation, while more recent mounds are brighter due to absence of vegetation and litter. Based on objective image classification we estimate that nearly 20% of the landscape is affected by mound disturbance, while in some localized regions up to 50% of the surface is affected by recent disturbance. Overall, our case study demonstrates the potential value of UAS platforms for acquiring high-resolution remote sensing data for detecting and mapping small-scale biological disturbance.

New geologic slip rates for the Agua Blanca Fault, northern Baja California, Mexico

NASA Astrophysics Data System (ADS)

Gold, P. O.; Behr, W. M.; Fletcher, J. M.; Hinojosa-Corona, A.; Rockwell, T. K.

2015-12-01

Within the southern San Andreas transform plate boundary system, relatively little is known regarding active faulting in northern Baja California, Mexico, or offshore along the Inner Continental Borderland. The inner offshore system appears to be fed from the south by the Agua Blanca Fault (ABF), which strikes northwest across the Peninsular Ranges of northern Baja California. Therefore, the geologic slip rate for the ABF also provides a minimum slip rate estimate for the offshore system, which is connected to the north to faults in the Los Angeles region. Previous studies along the ABF determined slip rates of ~4-6 mm/yr (~10% of relative plate motion). However, these rates relied on imprecise age estimates and offset geomorphic features of a type that require these rates to be interpreted as minima, allowing for the possibility that the slip rate for the ABF may be greater. Although seismically quiescent, the surface trace of the ABF clearly reflects Holocene activity, and given its connectivity with the offshore fault system, more quantitative slip rates for the ABF are needed to better understand earthquake hazard for both US and Mexican coastal populations. Using newly acquired airborne LiDAR, we have mapped primary and secondary fault strands along the segmented western 70 km of the ABF. Minimal development has left the geomorphic record of surface slip remarkably well preserved, and we have identified abundant evidence meter to km scale right-lateral displacement, including new Late Quaternary slip rate sites. We verified potential reconstructions at each site during summer 2015 fieldwork, and selected an initial group of three high potential slip rate sites for detailed mapping and geochronologic analyses. Offset landforms, including fluvial terrace risers, alluvial fans, and incised channel fill deposits, record displacements of ~5-80 m, and based on minimal soil development, none appear older than early Holocene. To quantitatively constrain landform ages, we collected surface and depth profile samples for 10Be cosmogenic exposure dating. We also identified sites for new paleoseismic excavations, and documented evidence of the last two earthquakes, each of which produced ~2.5 m of surface displacement. We expect new Holocene slip rates for the Agua Blanca Fault to be forthcoming in fall of 2015.

Assessment of habitat representation across a network of marine protected areas with implications for the spatial design of monitoring.

PubMed

Young, Mary; Carr, Mark

2015-01-01

Networks of marine protected areas (MPAs) are being adopted globally to protect ecosystems and supplement fisheries management. The state of California recently implemented a coast-wide network of MPAs, a statewide seafloor mapping program, and ecological characterizations of species and ecosystems targeted for protection by the network. The main goals of this study were to use these data to evaluate how well seafloor features, as proxies for habitats, are represented and replicated across an MPA network and how well ecological surveys representatively sampled fish habitats inside MPAs and adjacent reference sites. Seafloor data were classified into broad substrate categories (rock and sediment) and finer scale geomorphic classifications standard to marine classification schemes using surface analyses (slope, ruggedness, etc.) done on the digital elevation model derived from multibeam bathymetry data. These classifications were then used to evaluate the representation and replication of seafloor structure within the MPAs and across the ecological surveys. Both the broad substrate categories and the finer scale geomorphic features were proportionately represented for many of the classes with deviations of 1-6% and 0-7%, respectively. Within MPAs, however, representation of seafloor features differed markedly from original estimates, with differences ranging up to 28%. Seafloor structure in the biological monitoring design had mismatches between sampling in the MPAs and their corresponding reference sites and some seafloor structure classes were missed entirely. The geomorphic variables derived from multibeam bathymetry data for these analyses are known determinants of the distribution and abundance of marine species and for coastal marine biodiversity. Thus, analyses like those performed in this study can be a valuable initial method of evaluating and predicting the conservation value of MPAs across a regional network.

Assessment of Habitat Representation across a Network of Marine Protected Areas with Implications for the Spatial Design of Monitoring

PubMed Central

Young, Mary; Carr, Mark

2015-01-01

Networks of marine protected areas (MPAs) are being adopted globally to protect ecosystems and supplement fisheries management. The state of California recently implemented a coast-wide network of MPAs, a statewide seafloor mapping program, and ecological characterizations of species and ecosystems targeted for protection by the network. The main goals of this study were to use these data to evaluate how well seafloor features, as proxies for habitats, are represented and replicated across an MPA network and how well ecological surveys representatively sampled fish habitats inside MPAs and adjacent reference sites. Seafloor data were classified into broad substrate categories (rock and sediment) and finer scale geomorphic classifications standard to marine classification schemes using surface analyses (slope, ruggedness, etc.) done on the digital elevation model derived from multibeam bathymetry data. These classifications were then used to evaluate the representation and replication of seafloor structure within the MPAs and across the ecological surveys. Both the broad substrate categories and the finer scale geomorphic features were proportionately represented for many of the classes with deviations of 1-6% and 0-7%, respectively. Within MPAs, however, representation of seafloor features differed markedly from original estimates, with differences ranging up to 28%. Seafloor structure in the biological monitoring design had mismatches between sampling in the MPAs and their corresponding reference sites and some seafloor structure classes were missed entirely. The geomorphic variables derived from multibeam bathymetry data for these analyses are known determinants of the distribution and abundance of marine species and for coastal marine biodiversity. Thus, analyses like those performed in this study can be a valuable initial method of evaluating and predicting the conservation value of MPAs across a regional network. PMID:25760858

Seasat radar geomorphic applications in coastal and wetland environments, southeastern U.S

NASA Technical Reports Server (NTRS)

Macdonald, H. C.

1981-01-01

The application of Seasat Synthetic Aperture Radar (SAR) to the assessment of terrain conditions in coastal environments is considered. Drainage patterns and plant community spatial relationships can be adequately mapped as is shown by Seasat L-band imagery of the southeastern Gulf Coast and Atlantic Coastal Plain. Anomalously bright radar signatures are identified as characteristic of mangrove and cypress swamps. Marshes have a low radar return, less than that from non-marsh areas and open water in tidal channels. Drainage patterns for coastal plain transition zones can also be determined. Spaceborne imaging radar provides information which complements geomorphic analyses presently obtained with optical sensors.

75 FR 75501 - Notice of Permit Applications Received Under the Antarctic Conservation Act of 1978 (Pub. L. 95-541)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-03

... surface of ponds. The goal of the project is to define the rate of geomorphic change in Garwood Valley in response to changing climate conditions. The geomorphic record will be reconstructed over the past 1-=2- kyr to infer past climate-driven landscape alteration at the end of the LGM and examine the current...

Anthropogenic features and hillslope processes interaction

NASA Astrophysics Data System (ADS)

Tarolli, Paolo; Sofia, Giulia

2016-04-01

Topography emerges as a result of natural driving forces, but some human activities (such as mining, agricultural practices and the construction of road networks) directly or indirectly move large quantities of soil, which leave clear topographic signatures embedded on the Earth's morphology. These signatures can cause drastic changes to the geomorphological organization of the landscape, with direct consequences on Earth surface processes (Tarolli and Sofia, 2016). To this point, the present research investigates few case studies highlighting the influences of anthropogenic topographic signatures on hillslope processes, and it shows the effectiveness of High-Resolution Topography (HRT) derived from the recent remote sensing technologies (e.g. lidar, satellite, structure from motion photogrammetry), to better understand this interaction. The first example is related to agricultural terraces. In recent times, terraced areas acquired a new relevance to modern concerns about erosion and land instability, being the agricultural land mostly threatened by abandonment or intensification and specialization of agriculture, resulting in more landslide-prone bench terraces, or heavy land levelling with increased erosion. The second case study discusses about the role of agricultural and forest roads on surface erosion and landslides. The third case study investigates geomorphic processes in an open pit mine. In all case studies, HRT served as the basis for the development of new methodologies able to recognize and analyze changes on Earth surface processes along hillslopes. The results show how anthropogenic elements have crucial effects on sediment production and sediment delivery, also influencing the landscape connectivity. The availability of HRT can improve our ability to actually model anthropogenic morphologies, quantify them, and analyse the links between anthropogenic elements and geomorphic processes. The results presented here, and the creation and dissemination of HR datasets might allow the transfer the knowledge of geomorphic processes from the scientific to the practical world. Thus, it may allow an improved understanding and targeted mitigation of geomorphic changes during anthropogenic development and help guide future research directions for development-based watershed studies. References Tarolli, P., Sofia, G. (2016). Human topographic signatures and derived geomorphic processes across landscapes, Geomorphology, 255, 140-161, 10.1016/j.geomorph.2015.12.007.

Equilibrium-line altitude during the Antarctic Cold Reversal at Río Tranquilo glacier (47°S), Central Patagonia

NASA Astrophysics Data System (ADS)

Sagredo, E. A.; Ward, D.; Gonzalez, M. A.; Lowell, T. V.; Kelly, M. A.; Aravena, J. C.

2013-12-01

Documenting the magnitude of former glacial fluctuations is critical for understanding the mechanisms and climate signals underlying these glacial events. Here, we estimate the equilibrium line altitudes (ELA) associated with the most prominent glacial advance occurred during the Last Glacial Termination (T1) at Tranquilo glacier (47°S). Geomorphic evidence suggest that, following the Last Glacial Maximum, several small glaciers, which today occupy the headwalls of Río Tranquilo valley, expanded and coalesced, forming the extended version of the Tranquilo glacier at least three different times. 10Be ages suggest that the most prominent of these glacial advances occurred ~13 kyr BP, at the end of the Antarctic Cold Reversal (ACR). Based on glacial geomorphic mapping and the application of a glaciological model (GC2D), we reconstruct the former glacial surface at Tranquilo glacier and estimate the ELA for this major glacial advance. Preliminary data show that the equilibrium line altitude at Tranquilo glacier during the ACR could have been up to 500 m lower than the present. This study represents the first effort to quantify the ELA during the Antarctic Cold Reversal in Patagonia, and provides a baseline to decipher the climatic signals driving this glacial event.

Impact of flow routing on catchment area calculations, slope estimates, and numerical simulations of landscape development

NASA Astrophysics Data System (ADS)

Shelef, Eitan; Hilley, George E.

2013-12-01

Flow routing across real or modeled topography determines the modeled discharge and wetness index and thus plays a central role in predicting surface lowering rate, runoff generation, likelihood of slope failure, and transition from hillslope to channel forming processes. In this contribution, we compare commonly used flow-routing rules as well as a new routing rule, to commonly used benchmarks. We also compare results for different routing rules using Airborne Laser Swath Mapping (ALSM) topography to explore the impact of different flow-routing schemes on inferring the generation of saturation overland flow and the transition between hillslope to channel forming processes, as well as on location of saturation overland flow. Finally, we examined the impact of flow-routing and slope-calculation rules on modeled topography produced by Geomorphic Transport Law (GTL)-based simulations. We found that different rules produce substantive differences in the structure of the modeled topography and flow patterns over ALSM data. Our results highlight the impact of flow-routing and slope-calculation rules on modeled topography, as well as on calculated geomorphic metrics across real landscapes. As such, studies that use a variety of routing rules to analyze and simulate topography are necessary to determine those aspects that most strongly depend on a chosen routing rule.

Application of a new genetic classification and semi-automated geomorphic mapping approach in the Perth submarine canyon, Australia

NASA Astrophysics Data System (ADS)

Picard, K.; Nanson, R.; Huang, Z.; Nichol, S.; McCulloch, M.

2017-12-01

The acquisition of high resolution marine geophysical data has intensified in recent years (e.g. multibeam echo-sounding, sub-bottom profiling). This progress provides the opportunity to classify and map the seafloor in greater detail, using new methods that preserve the links between processes and morphology. Geoscience Australia has developed a new genetic classification approach, nested within the Harris et al (2014) global seafloor mapping framework. The approach divides parent units into sub-features based on established classification schemes and feature descriptors defined by Bradwell et al. (2016: http://nora.nerc.ac.uk/), the International Hydrographic Organization (https://www.iho.int) and the Coastal Marine and Ecological Classification Standard (https://www.cmecscatalog.org). Owing to the ecological significance of submarine canyon systems in particular, much recent attention has focused on defining their variation in form and process, whereby they can be classified using a range of topographic metrics, fluvial dis/connection and shelf-incising status. The Perth Canyon is incised into the continental slope and shelf of southwest Australia, covering an area of >1500 km2 and extending from 4700 m water depth to the shelf break in 170 m. The canyon sits within a Marine Protected Area, incorporating a Marine National Park and Habitat Protection Zone in recognition of its benthic and pelagic biodiversity values. However, detailed information of the spatial patterns of the seabed habitats that influence this biodiversity is lacking. Here we use 20 m resolution bathymetry and acoustic backscatter data acquired in 2015 by the Schmidt Ocean Institute plus sub-bottom datasets and sediment samples collected Geoscience Australia in 2005 to apply the new geomorphic classification system to the Perth Canyon. This presentation will show the results of the geomorphic feature mapping of the canyon and its application to better defining potential benthic habitats.

Comprehensive Seismological Monitoring of Geomorphic Processes in Taiwan

NASA Astrophysics Data System (ADS)

Chao, W. A.; Chen, C. H.

2016-12-01

Geomorphic processes such as hillslope mass wasting and river sediment transport are important for studying landscape dynamics. Mass movements induced from geomorphic events can generate seismic waves and be recorded by seismometers. Recent studies demonstrate that seismic monitoring techniques not only fully map the spatiotemporal patterns of geomorphic activity but also allow for exploration of the dynamic links between hillslope failures and channel processes, which may not be resolved by conventional techniques (e.g., optical remote sensing). We have recently developed a real-time landquake monitoring system (RLMS, here we use the term `landquake' to represent all hillslope failures such as rockfall, rock avalanche and landslide), which has been continuously monitoring landquake activities in Taiwan since June 2015 based on broadband seismic records, yielding source information (e.g., location, occurrence time, magnitude and mechanism) for large-sized events (http://140.112.57.117/main.html). Several seismic arrays have also been deployed over the past few years around the catchments and along the river channels in Taiwan for monitoring erosion processes at catchment scale, improving the spatiotemporal resolution in exploring the interaction between geomorphic events and specific meteorological conditions. Based on a forward model accounting for the impulsive impacts of saltating particles, we can further invert for the sediment load flux, a critical parameter in landscape evolution studies, by fitting the seismic observations only. To test the validity of the seismologically determined sediment load flux, we conduct a series of controlled dam breaking experiments that are advantageous in well constraining the spatiotemporal variations of the sediment transport. Incorporating the seismological constrains on geomorphic processes with the effects of tectonic and/or climate perturbations can provide valuable and quantitative information for more fully understanding and modeling of the dynamics of erosional mountain landscapes. Comprehensive seismic monitoring also yields important information for the evaluation, assessment and emergency response of hazardous geomorphic events.

Monitoring Corals and Submerged Aquatic Vegetation in Western Pacific Using Satellite Remote Sensing Integrated with Field Data

NASA Astrophysics Data System (ADS)

Roelfsema, C. M.; Phinn, S. R.; Lyons, M. B.; Kovacs, E.; Saunders, M. I.; Leon, J. X.

2013-12-01

Corals and Submerged Aquatic Vegetation (SAV) are typically found in highly dynamic environments where the magnitude and types of physical and biological processes controlling their distribution, diversity and function changes dramatically. Recent advances in the types of satellite image data and the length of their archives that are available globally, coupled with new techniques for extracting environmental information from these data sets has enabled significant advances to be made in our ability to map and monitor coral and SAV environments. Object Based Image Analysis techniques are one of the most significant advances in information extraction techniques for processing images to deliver environmental information at multiple spatial scales. This poster demonstrates OBIA applied to high spatial resolution satellite image data to map and monitor coral and SAV communities across a variety of environments in the Western Pacific that vary in their extent, biological composition, forcing physical factors and location. High spatial resolution satellite imagery (Quickbird, Ikonos and Worldview2) were acquired coincident with field surveys on each reef to collect georeferenced benthic photo transects, over various areas in the Western Pacific. Base line maps were created, from Roviana Lagoon Solomon island (600 km2), Bikini Atoll Marshall Island (800 Km2), Lizard Island, Australia (30 km2) and time series maps for geomorphic and benthic communities were collected for Heron Reef, Australia (24 km2) and Eastern Banks area of Moreton Bay, Australia (200 km2). The satellite image data were corrected for radiometric and atmospheric distortions to at-surface reflectance. Georeferenced benthic photos were acquired by divers or Autonomous Underwater Vehicles, analysed for benthic cover composition, and used for calibration and validation purposes. Hierarchical mapping from: reef/non-reef (1000's - 10000's m); reef type (100's - 1000's m); 'geomorphic zone' (10's - 100's m); to dominant components of benthic cover compositions (1 - 10's m); and individual benthic cover type scale (0.5-5.0's m), was completed using object based segmentation and semi-automated labelling through membership rules. Accuracy assessment of the satellite image based maps and field data sets scales maps produced with 90% maximum accuracy larger scales and less complex maps, versus 40 % at smaller scale and complex maps. The study showed that current data sets and object based analysis are able to reliable map at various scales and level of complexity covering a variety of extent and environments at various times; as a result science and management can use these tools to assess and understand the ecological processes taking place in coral and SAV environments.

Characterizing the Iron Wash fault: A fault line scarp in Utah

NASA Astrophysics Data System (ADS)

Kozaci, O.; Ostenaa, D.; Goodman, J.; Zellman, M.; Hoeft, J.; Sowers, J. M.; Retson, T.

2015-12-01

The Iron Wash fault (IWF) is an approximately 30 mile-long, NW-SE trending structure, oriented perpendicular to the San Rafael Monocline near Green River in Utah. IWF exhibits well-expressed geomorphic features such as a linear escarpment with consistently north side down displacement. The fault coincides with an abrupt change in San Rafael Monocline dip angle along its eastern margin. The IWF is exposed in incised drainages where Jurassic Navajo sandstone (oldest) and Lower Carmel Formation (old), are juxtaposed against Jurassic Entrada sandstone (younger) and Quaternary alluvium (youngest). To assess the recency of activity of the IWF we performed detailed geomorphic mapping and a paleoseismic trenching investigation. A benched trench was excavated across a Quaternary fluvial terrace remnant across the mapped trace of the IWF. The uppermost gravel units and overlying colluvium are exposed in the trench across the projection of the fault. In addition, we mapped the basal contact of the Quaternary gravel deposit in relation to the adjacent fault exposures in detail to show the geometry of the basal contact near and across the fault. We find no evidence of vertical displacement of these Quaternary gravels. A preliminary U-series date of calcite cementing unfaulted fluvial gravels and OSL dating of a sand lens within the unfaulted fluvial gravels yielded approximately 304,000 years and 78,000 years, respectively. These preliminary results of independent dating methods constrains the timing of last activity of the IWF to greater than 78,000 years before present suggesting that IWF not an active structure. Its distinct geomorphic expression is most likely the result of differential erosion, forming a fault-line scarp.

Assessing geomorphic sensitivity in relation to river capacity for adjustment

NASA Astrophysics Data System (ADS)

Reid, H. E.; Brierley, G. J.

2015-12-01

River sensitivity describes the nature and rate of channel adjustments. An approach to analysis of geomorphic river sensitivity outlined in this paper relates potential sensitivity based on the expected capacity of adjustment for a river type to the recent history of channel adjustment. This approach was trialled to assess low, moderate and high geomorphic sensitivity for four different types of river (10 reaches in total) along the Lower Tongariro River, North Island, New Zealand. Building upon the River Styles framework, river types were differentiated based upon valley setting (width and confinement), channel planform, geomorphic unit assemblages and bed material size. From this, the behavioural regime and potential for adjustment (type and extent) were determined. Historical maps and aerial photographs were geo-rectified and the channel planform digitised to assess channel adjustments for each reach from 1928 to 2007. Floodplain width controlled by terraces, exerted a strong influence upon reach scale sensitivity for the partly-confined, wandering, cobble-bed river. Although forced boundaries occur infrequently, the width of the active channel zone is constrained. An unconfined braided river reach directly downstream of the terrace-confined section was the most geomorphically sensitive reach. The channel in this reach adjusted recurrently to sediment inputs that were flushed through more confined, better connected upstream reaches. A meandering, sand-bed river in downstream reaches has exhibited negligible rates of channel migration. However, channel narrowing in this reach and the associated delta indicate that the system is approaching a threshold condition, beyond which channel avulsion is likely to occur. As this would trigger more rapid migration, this reach is considered to be more geomorphically sensitive than analysis of its low migration rate alone would indicate. This demonstrates how sensitivity is fashioned both by the behavioural regime of a reach and flow/sediment input from upstream. The approach to assess geomorphic river sensitivity outlined here could support 'room to move' or 'freedom space' approaches to river management by relating likely channel adjustments for the type of river under consideration to the area of land that is required to contain 'natural' patterns and rates of geomorphic functionality.

Enhancing the hydrogeological landscape (HGL) characterisation of the Greater Launceston area (GLA) through better understanding of dolerite weathering, stream water properties and a revised landscape evolution model

NASA Astrophysics Data System (ADS)

Moore, Leah; Nicholson, Allan; Cook, Wayne; Sweeney, Margaret

2014-05-01

In the Greater Launceston Area (GLA) in northern Tasmania, Australia, there is a widespread urban salinity problem with severe impacts on urban/peri-urban infrastructure in localised areas. Salinity patterns in the landscape (elevated flux to waterways; salt efflorescence at the land surface) could be related to: the underlying rock type, the thickness of regolith materials and hence the volume of the salt store, the landforms present and the amount of water passing over and through the landscape. In northern Tasmania secondary mineralogy on dolerite typically includes formation of Fe/Ca smectite phases (e.g. nontronite, saponite) and Fe-Ti oxides/sesquioxides (e.g. hematite, goethite) with some primary phases (e.g. Ca-plagioclase feldspar, augite) weathering through to a suite dominated by kaolinite clay and Fe-Ti oxides/sesquioxides. Deeply weathered profiles in the GLA have weathered to the kaolintite-clay dominant mineralogy and in places there are gibbsite/beidellite/hematite/goethite bauxites developed. Most existing salinity mapping emphasises salt manifestation over paleo-estuarine sediments of the Paleogene Tamar-Esk River system, so incorporation of deeply weathered Jurassic dolerite materials into the salt budget considerably augments the estimated potential hazard. Rapid stream surveys provide a snapshot of stream electrical conductivity (EC) over the study area at regular intervals allowing a broad evaluation of salt flux patterns in surfaces waters. Higher EC readings were obtained from selected streams draining: deeply weathered dolerite profiles (0.37 1.86 dS/m) and deeply weathered Paleogene paleo-estuarine sediments (0.49 to 1.16 dS/m). Lower values were measured on up-faulted dolerite blocks (<0.10 dS/m); moderately weathered, high relief dolerite (<0.03 dS/m), and in incised streams flowing over a rocky dolerite substrate (<0.03 dS/m). The patterns of stream EC reflect the nature of the regolith materials the streams drain, and match mapped patterns for distribution of deeply weathered Jurassic dolerite and moderately to deeply weathered bedded paleo-estuarine sediments of the Paleogene Tamar-Esk river system, some Quaternary terrace deposits along the Tamar and Esk Rivers; and some Holocene estuarine sediments. Recent geomorphic mapping has enabled development of a more comprehensive and consistent landscape evolution model that builds on existing knowledge. This model describes the influence of a progressively incising Tamar-Esk river system in response to episodic lowering of the local base level, with multiple episodes of valley widening as the river system stabilised after incision. Successive lowering events dissected earlier landforms, but locally remnant surfaces are preserved that represent former fluvial plain and terrace features. These processes were partially controlled by the structural configuration and contrasting resistance of the underlying lithologies, influencing the planform geometries of the rivers, and consequently the potential to preserve paleo-fluvial features. Because the Tamar River is an estuarine system, some of the lowermost preserved surfaces are likely to reflect marine processes (e.g. 5-7m; 10-12m ASL). The geomorphic mapping was conducted independently of the hydrogeological landscape (HGL) characterisation in the GLA, but there is strong correlation between the areas identified as having elevated salinity hazard (HGL) and newly mapped remnant surfaces in this landscape. This work complements HGL research and supports development of an increasingly rigorous evidence-based framework for GLA salinity hazard management.

Complex geohazard susceptibility zoning for effective landuse planning and catastroph prevention in developing countries

NASA Astrophysics Data System (ADS)

Hradecky, P.; Baron, I.

2012-04-01

The Czech Geological Survey conducted projects of geological mapping and complex geohazard susceptibility zoning in Nicaragua in the years 1997-2009. For selected areas in vicinity of major cities and towns basic geological maps at a scalle 1:50,000, maps of geomorphic features (Geomorphic Inventory Maps), Morphostructural Maps of estimated fault zones, and derived Geohazard Susceptibility maps were done. These maps were prepared during field campaigns by direct field mapping, analysis of remote-sensing data, communicating the local authorities, interwieving the local inhabitants and with very close cooperation with the local partner of the projects - the Instituto Nicaragüense de Estudios Territoriales (INETER). The resulting maps and explanatory reports presented the dangerous natural processes that occurred in each respective area in the past and proposed preventive measures in detail. Zones evaluated as highly susceptible, e.g., to (i) mass movements, (ii) large inundations, (iii) torrential flooding, (iv) seismogenic liquefaction, etc., were presented in bold colours on the maps. Such maps and reports were presented to local authorities and inhabitants of respective cities during public breefings at the end of each mapping campaign. In such a way, areas of Pacific volcanic ridge (1997-2003), Jinotega (2004), Somoto (2005), Estelí (2006), Boaco and Santa Lucia (2007, 2008), Sebaco (2008) and Jalapa (2009) were elaborated. The maps then served to the INETER for implementation into the landuse plans, evacuation routes and other preventive measures to protect and save human lives and inftrastructure. This approach could serve as a muster for a simple, cost effective and relatively fast geohazards susceptibility evaluation of any area in any developing country. The projects also paid attention to capacity building of our Nicaraguan partners. These projects of the Czech Geological Survey were conducted as the international aid of the Czech Republic to Nicaragua, financed by the Ministry of the Czech Republic

Human geomorphic footprint and global geomorphic change: implications for hydrogeomorphic hazards

NASA Astrophysics Data System (ADS)

Remondo, Juan

2010-05-01

The human geomorphic footprint (HGF), expressed as the area affected by the construction of new 'anthropogeoforms' or the volume of geologic materials directly or indirectly displaced by human action has grown considerably in the last decades. Available data suggest that the present HGF is roughly 50,000 km2 a-1 of new anthropogeoforms and 300 x109 t a-1 of solid materials transferred from one part of the earth's surface to another. The latter represents a 'technological denudation' that could be 1-2 orders of magnitude greater than denudation by natural agents or sediment transport by the world's rivers. This implies a profound modification of geomorphic processes that produces a series of often disregarded environmental consequences. Some of those can by directly linked to excavation/accumulation activities and are essentially local, but in other cases the possible relationship appears to be more indirect and could have a widespread character. The transformation of land surface by human action is shown not only by landform construction and transfer of geologic materials, but also by land-use change in general and modification of the characteristics of the surface layer. This seems to affect both the hydrologic response and the sensitivity of that surface layer to different geomorphic agents. The magnitude of the above mentioned modification is logically related to the intensity of human activities, themselves related to the number of people on the planet and their economic and technological capabilities, which grow practically in all regions of the planet. It is thus reasonable to expect that the HGF and its effects should grow with time. If this were so, we should expect to find evidences of a general acceleration of geomorphic processes in the world that could represent a 'global geomorphic change'. The final expression of geomorphic processes, which could be used to test that hypothesis, is sediment generation and deposition. Data are presented on sedimentation rates in different areas showing that in most of them sedimentation has increased significantly during the last century (by about one order of magnitude in most cases) and that such increase does not seem to be related to climate but rather to human activity. If a global geomorphic change is indeed taking place, an increase in the frequency/intensity of related hazards, such as landslides or floods, should be expected. Data are presented indicating that it could be so. If what the data presented suggest is confirmed by further and deeper analyses, existing hazard and risk assessments for those processes should be reconsidered, because they would likely represent underestimates. The CAMGEO Team is formed by the following persons: Antonio Cendrero1, Gonzalo Méndez2, Jaime Bonachea1, José Gómez-Arozamena1, José Luis Cavallotto5, José Manuel Naredo3, Juan Remondo1, Lazaro V. Zuquette6, Luis Salas1, Luis M. Forte4, Marcilene Dantas-Ferreira6, Maria Angélica de O. Bezerra7, Mario da Silva, Martín A. Hurtado4, Osni J. Pejon6, Victoria Rivas1, Viola M. Bruschi1. 1) Universidad de Cantabria, Spain; 2) Universidad de Vigo, Spain; 3) Universidad Politécnica de Madrid, Spain; 4) Universidad Nacional de La Plata, Argentina; 5) Servicio de Hidrografía Naval, Argentina; 6) Universidade de Sao Paulo, Sao Carlos, Brazil; 7) Universidade Federal de Mato Grosso do Sul, Brazil.

Active, capable, and potentially active faults - a paleoseismic perspective

USGS Publications Warehouse

Machette, M.N.

2000-01-01

Maps of faults (geologically defined source zones) may portray seismic hazards in a wide range of completeness depending on which types of faults are shown. Three fault terms - active, capable, and potential - are used in a variety of ways for different reasons or applications. Nevertheless, to be useful for seismic-hazards analysis, fault maps should encompass a time interval that includes several earthquake cycles. For example, if the common recurrence in an area is 20,000-50,000 years, then maps should include faults that are 50,000-100,000 years old (two to five typical earthquake cycles), thus allowing for temporal variability in slip rate and recurrence intervals. Conversely, in more active areas such as plate boundaries, maps showing faults that are <10,000 years old should include those with at least 2 to as many as 20 paleoearthquakes. For the International Lithosphere Programs' Task Group II-2 Project on Major Active Faults of the World our maps and database will show five age categories and four slip rate categories that allow one to select differing time spans and activity rates for seismic-hazard analysis depending on tectonic regime. The maps are accompanied by a database that describes evidence for Quaternary faulting, geomorphic expression, and paleoseismic parameters (slip rate, recurrence interval and time of most recent surface faulting). These maps and databases provide an inventory of faults that would be defined as active, capable, and potentially active for seismic-hazard assessments.

Prediction of lake depth across a 17-state region in the United States

USGS Publications Warehouse

Oliver, Samantha K.; Soranno, Patricia A.; Fergus, C. Emi; Wagner, Tyler; Winslow, Luke A.; Scott, Caren E.; Webster, Katherine E.; Downing, John A.; Stanley, Emily H.

2016-01-01

Lake depth is an important characteristic for understanding many lake processes, yet it is unknown for the vast majority of lakes globally. Our objective was to develop a model that predicts lake depth using map-derived metrics of lake and terrestrial geomorphic features. Building on previous models that use local topography to predict lake depth, we hypothesized that regional differences in topography, lake shape, or sedimentation processes could lead to region-specific relationships between lake depth and the mapped features. We therefore used a mixed modeling approach that included region-specific model parameters. We built models using lake and map data from LAGOS, which includes 8164 lakes with maximum depth (Zmax) observations. The model was used to predict depth for all lakes ≥4 ha (n = 42 443) in the study extent. Lake surface area and maximum slope in a 100 m buffer were the best predictors of Zmax. Interactions between surface area and topography occurred at both the local and regional scale; surface area had a larger effect in steep terrain, so large lakes embedded in steep terrain were much deeper than those in flat terrain. Despite a large sample size and inclusion of regional variability, model performance (R2 = 0.29, RMSE = 7.1 m) was similar to other published models. The relative error varied by region, however, highlighting the importance of taking a regional approach to lake depth modeling. Additionally, we provide the largest known collection of observed and predicted lake depth values in the United States.

Anthropogenic control on geomorphic process rates: can we slow down the erosion rates? (Geomorphology Outstanding Young Scientist Award & Penck Lecture)

NASA Astrophysics Data System (ADS)

Vanacker, V.

2012-04-01

The surface of the Earth is changing rapidly, largely in response to anthropogenic perturbation. Direct anthropogenic disturbance of natural environments may be much larger in many places than the (projected) indirect effects of climate change. There is now large evidence that humans have significantly altered geomorphic process rates, mainly through changes in vegetation composition, density and cover. While much attention has been given to the impact of vegetation degradation on geomorphic process rates, I suggest that the pathway of restoration is equally important to investigate. First, vegetation recovery after crop abandonment has a rapid and drastic impact on geomorphic process rates. Our data from degraded catchments in the tropical Andes show that erosion rates can be reduced by up to 100 times when increasing the protective vegetation cover. During vegetation restoration, the combined effects of the reduction in surface runoff, sediment production and hydrological connectivity are stronger than the individual effects together. Therefore, changes in erosion and sedimentation during restoration are not simply the reverse of those observed during degradation. Second, anthropogenic perturbation causes a profound but often temporary change in geomorphic process rates. Reconstruction of soil erosion rates in Spain shows us that modern erosion rates in well-vegetated areas are similar to long-term rates, despite evidence of strong pulses in historical erosion rates after vegetation clearance and agriculture. The soil vegetation system might be resilient to short pulses of accelerated erosion (and deposition), as there might exist a dynamic coupling between soil erosion and production also in degraded environments.

Geomorphic factors related to the persistence of subsurface oil from the Exxon Valdez oil spill

USGS Publications Warehouse

Nixon, Zachary; Michel, Jacqueline; Hayes, Miles O.; Irvine, Gail V.; Short, Jeffrey

2013-01-01

Oil from the 1989 Exxon Valdez oil spill has persisted along shorelines of Prince William Sound, Alaska, for more than two decades as both surface and subsurface oil residues. To better understand the distribution of persistent subsurface oil and assess the potential need for further restoration, a thorough and quantitative understanding of the geomorphic factors controlling the presence or absence of subsurface oil is required. Data on oiling and geomorphic features were collected at 198 sites in Prince William Sound to identify and quantify the relationships among these geomorphic factors and the presence and absence of persistent subsurface oil. Geomorphic factors associated with the presence of subsurface oil were initial oil exposure, substrate permeability, topographic slope, low exposure to waves, armoring on gravel beaches, tombolos, natural breakwaters, and rubble accumulations. Geomorphic factors associated with the absence of subsurface oil were impermeable bedrock; platforms with thin sediment veneer; fine-grained, well-sorted gravel beaches with no armor; and low-permeability, raised bay-bottom beaches. Relationships were found between the geomorphic and physical site characteristics and the likelihood of encountering persistent subsurface oiling at those sites. There is quantitative evidence of more complex interactions between the overall wave energy incident at a site and the presence of fine-scale geomorphic features that may have provided smaller, local wave energy sheltering of oil. Similarly, these data provide evidence for interactions between the shoreline slope and the presence of angular rubble, with decreased likelihood for encountering subsurface oil at steeply sloped sites except at high-angle sheltered rubble shoreline locations. These results reinforce the idea that the interactions of beach permeability, stability, and site-specific wave exposure are key drivers for subsurface oil persistence in exposed and intermittently exposed mixed gravel beach and rocky shoreline environments.

Using earthquake-triggered landslides as a hillslope-scale shear strength test: Insights into rock strength properties at geomorphically relevant spatial scales in high-relief, tectonically active settings

NASA Astrophysics Data System (ADS)

Gallen, Sean; Clark, Marin; Godt, Jonathan; Lowe, Katherine

2016-04-01

The material strength of rock is known to be a fundamental property in setting landscape form and geomorphic process rates as it acts to modulate feedbacks between earth surface processes, tectonics, and climate. Despite the long recognition of its importance in landscape evolution, a quantitative understanding of the role of rock strength in affecting geomorphic processes lags our knowledge of the influence of tectonics and climate. This gap stems largely from the fact that it remains challenging to quantify rock strength at the hillslope scale. Rock strength is strongly scale dependent because the number, size, spacing, and aperture of fractures sets the upper limit on rock strength, making it difficult to extrapolate laboratory measurements to landscape-scale interpretations. Here we present a method to determine near-surface rock strength at the hillslope-scale, relying on earthquake-triggered landslides as a regional-scale "shear strength" test. We define near-surface strength as the average strength of rock sample by the landslides, which is typically < 10 m. Based on a Newmark sliding block model, which approximates slope stability during an earthquake assuming a material with frictional and cohesive strength, we developed a coseismic landslide model that is capable of reproducing statistical characteristics of the distribution of earthquake-triggered landslides. We present results from two well-documented case-studies of earthquakes that caused widespread mass-wasting; the 2008 Mw 7.9 Wenchuan Earthquake, Sichuan Province, China and the 1994 Mw. 6.8 Northridge Earthquake, CA, USA. We show how this model can be used to determine near-surface rock strength and reproduce mapped landslide patterns provided the spatial distribution of local hillslope gradient, earthquake peak ground acceleration (PGA), and coseismic landsliding are well constrained. Results suggest that near-surface rock strength in these tectonically active settings is much lower than that obtained using typical laboratory shear strength measurements on intact rock samples. Furthermore, the near-surface material strength is similar between the study areas despite differences in tectonic, climatic, and lithologic conditions. Variations in near-surface strength within each setting appear to be more strongly associated with factors contributing to the weakening rock through chemical or physical weathering, such as mean annual precipitation and distance to active faults (a proxy for rock shattering intensity), rather than intrinsic lithologic properties. We hypothesize that the shattering of rock through long-term permanent strain accumulation and by repeated earthquakes is an important mechanism that can explain low rock strength values among the different study sites and the spatial pattern of rock strength within each location. These findings emphasize the potential role of factors other than lithology in controlling the spatial distribution of near-surface rock strength in high-relief, tectonically active settings, which has important implications for understanding the evolution of landscapes, interpreting tectonic and climatic signals from topography, critical zone processes, and natural hazard assessment.

LiDAR DTMs and anthropogenic feature extraction: testing the feasibility of geomorphometric parameters in floodplains

NASA Astrophysics Data System (ADS)

Sofia, G.; Tarolli, P.; Dalla Fontana, G.

2012-04-01

In floodplains, massive investments in land reclamation have always played an important role in the past for flood protection. In these contexts, human alteration is reflected by artificial features ('Anthropogenic features'), such as banks, levees or road scarps, that constantly increase and change, in response to the rapid growth of human populations. For these areas, various existing and emerging applications require up-to-date, accurate and sufficiently attributed digital data, but such information is usually lacking, especially when dealing with large-scale applications. More recently, National or Local Mapping Agencies, in Europe, are moving towards the generation of digital topographic information that conforms to reality and are highly reliable and up to date. LiDAR Digital Terrain Models (DTMs) covering large areas are readily available for public authorities, and there is a greater and more widespread interest in the application of such information by agencies responsible for land management for the development of automated methods aimed at solving geomorphological and hydrological problems. Automatic feature recognition based upon DTMs can offer, for large-scale applications, a quick and accurate method that can help in improving topographic databases, and that can overcome some of the problems associated with traditional, field-based, geomorphological mapping, such as restrictions on access, and constraints of time or costs. Although anthropogenic features as levees and road scarps are artificial structures that actually do not belong to what is usually defined as the bare ground surface, they are implicitly embedded in digital terrain models (DTMs). Automatic feature recognition based upon DTMs, therefore, can offer a quick and accurate method that does not require additional data, and that can help in improving flood defense asset information, flood modeling or other applications. In natural contexts, morphological indicators derived from high resolution topography have been proven to be reliable for feasible applications. The use of statistical operators as thresholds for these geomorphic parameters, furthermore, showed a high reliability for feature extraction in mountainous environments. The goal of this research is to test if these morphological indicators and objective thresholds can be feasible also in floodplains, where features assume different characteristics and other artificial disturbances might be present. In the work, three different geomorphic parameters are tested and applied at different scales on a LiDAR DTM of typical alluvial plain's area in the North East of Italy. The box-plot is applied to identify the threshold for feature extraction, and a filtering procedure is proposed, to improve the quality of the final results. The effectiveness of the different geomorphic parameters is analyzed, comparing automatically derived features with the surveyed ones. The results highlight the capability of high resolution topography, geomorphic indicators and statistical thresholds for anthropogenic features extraction and characterization in a floodplains context.

Preliminary Investigation and Surficial Mapping of the Faults North and South of Blacktail Butte, Teton County, Wyoming

NASA Astrophysics Data System (ADS)

Wittke, S.

2016-12-01

The Wyoming State Geological Survey has focused on surficial mapping and examination of the location and offset of faults north and south of Blacktail Butte in eastern Jackson Hole, Wyoming. The fault strands south of Blacktail Butte are classified as Late Quaternary, the faults north of the butte are considered Class B structures by the USGS. Little to no detailed studies, including paleoseismic investigations or fault scarp morphology, have been conducted on these fault strands. The acquisition of LiDAR for the Grand Teton National Park and recent aerial photographs provided data necessary for revised mapping and geomorphic interpretation of fault-related features north and south of Blacktail Butte. New fault traces and geomorphic features were identified in the LiDAR data which had not been previously mapped. Mapped fault traces are intermittent, forming a 1.5 km-long graben that extends south from Blacktail Butte and crosses a loess-mantle late-Pleistocene terrace generated from the Pinedale glaciation. Other lineaments were identified that continued for another 0.5 km to the south. With very little vertical offset across the system and comparatively short fault strands, the faults may represent secondary features related to movement on another unidentified fault within the basin. The secondary faults north of Blacktail Butte were mapped based on geomorphic features and through LiDAR-based spatial analysis. The fault scarps are relatively short and are present on alluvial fan and/or terrace deposits related to the Pinedale glaciation or on undated Holocene deposits. The scarps have little net vertical offset, suggesting they could also be secondary features related to movement from another unidentified fault within the basin. Improved understanding of these fault strands is significant because of the vicinity to populated areas within Jackson Hole and the possible relevance to the Teton Fault system. To our knowledge, these fault strands have not been proposed as antithetic to the Teton fault. The faults are located on the eastern edge of the valley, approximately 8-16 km from the Teton fault, and based on their orientation and sense of slip, the Teton fault may be the unidentified fault within the basin. Detailed paleoseismic surveys, including fault trenching, may shed light on the question in the future.

Identification of large geomorphological anomalies based on 2D discrete wavelet transform

NASA Astrophysics Data System (ADS)

Doglioni, A.; Simeone, V.

2012-04-01

The identification and analysis based on quantitative evidences of large geomorphological anomalies is an important stage for the study of large landslides. Numerical geomorphic analyses represent an interesting approach to this kind of studies, allowing for a detailed and pretty accurate identification of hidden topographic anomalies that may be related to large landslides. Here a geomorphic numerical analyses of the Digital Terrain Model (DTM) is presented. The introduced approach is based on 2D discrete wavelet transform (Antoine et al., 2003; Bruun and Nilsen, 2003, Booth et al., 2009). The 2D wavelet decomposition of the DTM, and in particular the analysis of the detail coefficients of the wavelet transform can provide evidences of anomalies or singularities, i.e. discontinuities of the land surface. These discontinuities are not very evident from the DTM as it is, while 2D wavelet transform allows for grid-based analysis of DTM and for mapping the decomposition. In fact, the grid-based DTM can be assumed as a matrix, where a discrete wavelet transform (Daubechies, 1992) is performed columnwise and linewise, which basically represent horizontal and vertical directions. The outcomes of this analysis are low-frequency approximation coefficients and high-frequency detail coefficients. Detail coefficients are analyzed, since their variations are associated to discontinuities of the DTM. Detailed coefficients are estimated assuming to perform 2D wavelet transform both for the horizontal direction (east-west) and for the vertical direction (north-south). Detail coefficients are then mapped for both the cases, thus allowing to visualize and quantify potential anomalies of the land surface. Moreover, wavelet decomposition can be pushed to further levels, assuming a higher scale number of the transform. This may potentially return further interesting results, in terms of identification of the anomalies of land surface. In this kind of approach, the choice of a proper mother wavelet function is a tricky point, since it conditions the analysis and then their outcomes. Therefore multiple levels as well as multiple wavelet analyses are guessed. Here the introduced approach is applied to some interesting cases study of south Italy, in particular for the identification of large anomalies associated to large landslides at the transition between Apennine chain domain and the foredeep domain. In particular low Biferno valley and Fortore valley are here analyzed. Finally, the wavelet transforms are performed on multiple levels, thus trying to address the problem of which is the level extent for an accurate analysis fit to a specific problem. Antoine J.P., Carrette P., Murenzi R., and Piette B., (2003), Image analysis with two-dimensional continuous wavelet transform, Signal Processing, 31(3), pp. 241-272, doi:10.1016/0165-1684(93)90085-O. Booth A.M., Roering J.J., and Taylor Perron J., (2009), Automated landslide mapping using spectral analysis and high-resolution topographic data: Puget Sound lowlands, Washington, and Portland Hills, Oregon, Geomorphology, 109(3-4), pp. 132-147, doi:10.1016/j.geomorph.2009.02.027. Bruun B.T., and Nilsen S., (2003), Wavelet representation of large digital terrain models, Computers and Geoscience, 29(6), pp. 695-703, doi:10.1016/S0098-3004(03)00015-3. Daubechies, I. (1992), Ten lectures on wavelets, SIAM.

Surficial Geologic Map of the Worcester North-Oxford- Wrentham-Attleboro Nine-Quadrangle Area in South- Central Massachusetts

USGS Publications Warehouse

Stone, Byron D.; Stone, Janet R.; DiGiacomo-Cohen, Mary L.

2008-01-01

The surficial geologic map layer shows the distribution of nonlithified earth materials at land surface in an area of nine 7.5-minute quadrangles (417 mi2 total) in south-central Massachusetts (fig. 1). Across Massachusetts, these materials range from a few feet to more than 500 ft in thickness. They overlie bedrock, which crops out in upland hills and in resistant ledges in valley areas. The geologic map differentiates surficial materials of Quaternary age on the basis of their lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic features, stratigraphic relationships, and age. Surficial materials also are known in engineering classifications as unconsolidated soils, which include coarse-grained soils, fine-grained soils, or organic fine-grained soils. Surficial materials underlie and are the parent materials of modern pedogenic soils, which have developed in them at the land surface. Surficial earth materials significantly affect human use of the land, and an accurate description of their distribution is particularly important for water resources, construction aggregate resources, earth-surface hazards assessments, and land-use decisions. The mapped distribution of surficial materials that lie between the land surface and the bedrock surface is based on detailed geologic mapping of 7.5-minute topographic quadrangles, produced as part of an earlier (1938-1982) cooperative statewide mapping program between the U.S. Geological Survey and the Massachusetts Department of Public Works (now Massachusetts Highway Department) (Page, 1967; Stone, 1982). Each published geologic map presents a detailed description of local geologic map units, the genesis of the deposits, and age correlations among units. Previously unpublished field compilation maps exist on paper or mylar sheets and these have been digitally rendered for the present map compilation. Regional summaries based on the Massachusetts surficial geologic mapping studies discuss the ages of multiple glaciations, the nature of glaciofluvial, glaciolacustrine, and glaciomarine deposits, and the processes of ice advance and retreat across Massachusetts (Koteff and Pessl, 1981; papers in Larson and Stone, 1982; Oldale and Barlow, 1986; Stone and Borns, 1986; Warren and Stone, 1986). This compilation of surficial geologic materials is an interim product that defines the areas of exposed bedrock and the boundaries between glacial till, glacial stratified deposits, and overlying postglacial deposits. This work is part of a comprehensive study to produce a statewide digital map of the surficial geology at a 1:24,000-scale level of accuracy. This surficial geologic map layer covering nine quadrangles revises previous digital surficial geologic maps (Stone and others, 1993; MassGIS, 1999) that were compiled on base maps at regional scales of 1:125,000 and 1:250,000. The purpose of this study is to provide fundamental geologic data for the evaluation of natural resources, hazards, and land information within the Commonwealth of Massachusetts.

Rates of surface lowering and landscape development in southern South Africa: a cosmogenic view

NASA Astrophysics Data System (ADS)

Richardson, Janet; Vanacker, Veerle; Lang, Andreas; Hodgson, David

2016-04-01

The landscape of southern South Africa is characterised by large-scale erosion surfaces, including extensive pediments and multiple strath terraces, which document discordant river evolution through resistant quarzitic lithologies of the Cape Fold Belt (CFB). The timing and rate of erosion is poorly constrained. New cosmogenic ages from surfaces in South Africa are presented using in situ produced 10Be. Strath terraces in deeply incised rivers at two sites within the CFB indicate slow rates of erosion (1.54 - 11.79 m/Ma), which are some of the lowest rates recorded globally. Four pediment surfaces and a depth profile of the thickest pediment were also dated, and the results indicate that there are low rates of surface lowering on the pediments (0.44 - 1.24 m/Ma). The pediments are long-lived features (minimum exposure ages of 0.47 - 1.09 Ma), and are now deeply dissected. Given the minimum exposure ages, calculated river incision rates (42- 203 m/Ma) suggest that after a long period of geomorphic stability during pediment formation there was a discrete phase of increased geomorphic activity. The calculated minimum exposure ages are considered dubious because: 1) known rates of surrounding river incision (published and ours); 2) the climate conditions and time necessary for ferricrete formation on the pediment surfaces and; 3) the deeply incised catchments in the CFB on which the pediments sit, which all point to the pediments being much older. The pediments are fossilised remnants of a much larger geomorphic surface that formed after the main phase of exhumation in southern Africa. They form a store of sediment that currently sit above the surrounding rivers that have some of the lowest erosion rates in the world. These results indicate that steep topography can prevail even in areas of low erosion and tectonic quiescence, and that whilst cosmogenic dating of landscapes is an exciting development in earth sciences, care is needed especially in ancient settings. We strongly suggest benchmarking chronometric information with geomorphic and stratigraphic information.

Martian crater counts on Elysium Mons

NASA Technical Reports Server (NTRS)

Mcbride, Kathleen; Barlow, Nadine G.

1990-01-01

Without returned samples from the Martian surface, relative age chronologies and stratigraphic relationships provide the best information for determining the ages of geomorphic features and surface regions. Crater-size frequency distributions of six recently mapped geological units of Elysium Mons were measured to establish their relative ages. Most of the craters on Elysium Mons and the adjacent plains units are between 500 and 1000 meters in diameter. However, only craters 1 km in diameter or larger were used because of inadequate spatial resolution of some of the Viking images and to reduce probability of counting secondary craters. The six geologic units include all of the Elysium Mons construct and a portion of the plains units west of the volcano. The surface area of the units studied is approximately 128,000 sq km. Four of the geologic units were used to create crater distribution curves. There are no craters larger than 1 km within the Elysium Mons caldera. Craters that lacked raised rims, were irregularly shaped, or were arranged in a linear pattern were assumed to be endogenic in origin and not counted. A crater frequency distribution analysis is presented.

Investigating Strain Transfer Along the Southern San Andreas Fault: A Geomorphic and Geodetic Study of Block Rotation in the Eastern Transverse Ranges, Joshua Tree National Park, CA

NASA Astrophysics Data System (ADS)

Guns, K. A.; Bennett, R. A.; Blisniuk, K.

2017-12-01

To better evaluate the distribution and transfer of strain and slip along the Southern San Andreas Fault (SSAF) zone in the northern Coachella valley in southern California, we integrate geological and geodetic observations to test whether strain is being transferred away from the SSAF system towards the Eastern California Shear Zone through microblock rotation of the Eastern Transverse Ranges (ETR). The faults of the ETR consist of five east-west trending left lateral strike slip faults that have measured cumulative offsets of up to 20 km and as low as 1 km. Present kinematic and block models present a variety of slip rate estimates, from as low as zero to as high as 7 mm/yr, suggesting a gap in our understanding of what role these faults play in the larger system. To determine whether present-day block rotation along these faults is contributing to strain transfer in the region, we are applying 10Be surface exposure dating methods to observed offset channel and alluvial fan deposits in order to estimate fault slip rates along two faults in the ETR. We present observations of offset geomorphic landforms using field mapping and LiDAR data at three sites along the Blue Cut Fault and one site along the Smoke Tree Wash Fault in Joshua Tree National Park which indicate recent Quaternary fault activity. Initial results of site mapping and clast count analyses reveal at least three stages of offset, including potential Holocene offsets, for one site along the Blue Cut Fault, while preliminary 10Be geochronology is in progress. This geologic slip rate data, combined with our new geodetic surface velocity field derived from updated campaign-based GPS measurements within Joshua Tree National Park will allow us to construct a suite of elastic fault block models to elucidate rates of strain transfer away from the SSAF and how that strain transfer may be affecting the length of the interseismic period along the SSAF.

Using age of colonizing douglas-fir for the dating of young geomorphic surfaces: a case study

USGS Publications Warehouse

Pierson, Thomas C.

2013-01-01

Dating of many types of young (<500 year), dynamic, geomorphic landforms (e.g. mass-movement erosional tracks and deposits, alluvial terraces, flood plains, etc.) for purposes of hazard assessment and mitigation commonly requires greater dating precision than is available through radiocarbon dating or other methods. Ages of trees growing on landform surfaces have been used in a number of studies to estimate the time of landform creation or surface clearing, but the time lag between surface formation or disturbance and the reestablishment of trees can vary from 1 to more than 200 years (Desloges and Ryder 1990; Frenzen et al. 1988, 2005; Larsen and Bliss 1998; McCarthy and Luckman 1993; Sigafoos and Hendricks 1969; Winter et al. 2002). Appropriate lag times for selected tree species and for particular climatic and altitudinal ranges must be determined for the method to be useful.

LIDAR data to support coastal erosion analysis: the Conero study case

NASA Astrophysics Data System (ADS)

Calligaro, Simone; Sofia, Giulia; Guarnieri, Alberto; Tarolli, Paolo

2013-04-01

In the last decades, the topic of coastal erosion and the derived risk have been subject of a growing interest for public authorities and researchers. Recent major natural events, such as hurricanes, tsunamis, and sea level rising, called the attention of media and society, underlining serious concerns about such problems. In a high-density populated country such as Italy, where tourism is one of the major economic activities, the coastal erosion is really a critical issue. In April 2010, along a reach of the coast of Ventotene Island, two young students tragically died, killed by a rock fall. This event dramatically stressed public authorities about the effectiveness of structural and non-structural measures for the mitigation of such phenomena. It is clear that an improving of the actual knowledge about coastal erosion is needed, especially to monitor such events and to set alert systems. In the last few years, airborne LIDAR technology led to a dramatic increase in terrain information. Airborne LiDAR and Terrestrial Laser Scanner (TLS) derived high-resolution Digital Terrain Models (DTMs) have opened avenues for hydrologic and geomorphologic studies (Tarolli et al., 2009). In general, all the main surface processes signatures are correctly recognized using a DTM with cell sizes of 1 m. Having said that, some sub-meter grid sizes may be more suitable in those situations where the analysis of micro topography related to micro changes due to slope failures is critical for risk assessment, and the Terrestrial Laser Scanner (TLS) has been proven to be a useful tool for such detailed field survey. The acquired elevation data with TLS allow to derive a centimeters high quality DTMs. The possibility to detect in detail the slope failures signatures results in a better understanding and mapping of the erosion susceptibility, and of those areas where slope failures are more likely to happen. In addition, these information can be also considered as the basis to develop risk maps. At this regard, a clear example is the case of coastal erosion. In this work a detailed TLS survey was carried out in summer 2012, in the Conero Regional Park (Marche, province of Ancona), along the "spiaggia Urbani" and "spiaggia San Michele". These two study areas present several sections affected by erosion, rock falls and slope failures. They are also a part of a very prestigious place for tourism during the summer season; therefore deriving risk maps is critical. Thanks to the TLS survey, it was possible to obtain a 10 cm resolution DTM covering a reach of about 1.5 km of the coast. This high resolution DTM was used to derive topographic attributes such as curvature from which it has been possible to automatically recognize (Tarolli et al, 2012) and map the surface features related to any surface instabilities. These topographic information and results will also serve as the reference point for future yearly TLS surveys, that absolutely will help in recognizing any micro changes and slope failures, improving the delineation of risk maps. References Tarolli, P., Arrowsmith, J.R., Vivoni, E.R. (2009). Understanding earth surface processes from remotely sensed digital terrain models, Geomorphology, 113, 1-3, doi:10.1016/j.geomorph. 2009.07.005. Tarolli, P., Sofia, G., Dalla Fontana, G. (2012). Geomorphic features extraction from high-resolution topography: landslide crowns and bank erosion, Natural Hazards, 61, 65-83, doi:10.1007/s11069-010-9695-2.

Modelling geomorphic responses to human perturbations: Application to the Kander river, Switzerland

NASA Astrophysics Data System (ADS)

Ramirez, Jorge; Zischg, Andreas; Schürmann, Stefan; Zimmermann, Markus; Weingartner, Rolf; Coulthard, Tom; Keiler, Margreth

2017-04-01

Before 1714 the Kander river (Switzerland) flowed into the Aare river causing massive flooding and for this reason the Kander river was deviated (Kander correction) to lake Thun. The Kander correction was a pioneering hydrological project and induced a major human change to the landscape, but had unintended hydrological and geomorphic impacts that cascaded upstream and downstream. For example doubling the catchment area of Lake Thun, which gave rise to major flood problems, cessation of direct sediment delivery to the Aare, and sediment flux to lake Thun forming the Kander delta. More importantly the Kander correction shortened the Kander river and substantially increased the slope and bed shear of the Kander upstream from the correction. Consequently impacts of the correction cascaded upstream as a migrating knickpoint and eroded the river channel at unprecedented rates. Today we may have at our disposal the theoretical and empirical foundations to foresee the consequences of human intervention into natural systems. One method to investigate such geomorphic changes are numerical models that estimate the evolution of rivers by simulating the movement of water and sediment. Although much progress has been made in the development of these geomorphic models, few models have been tested in circumstances with rare perturbations and extreme forcings. As such, it remains uncertain if geomorphic models are useful and stable in extreme situations that include large movements of sediment and water. Here, in this study, we use historic maps and documents to develop a detailed geomorphic model of the Kander river starting in the year 1714. We use this model to simulate the extreme geomorphic events that preceded the deviation of the Kander river into Lake Thun and simulate changes to the river until conditions become relatively stable. We test our model by replicating long term impacts to the river that include 1) rates of incision within the correction, 2) knickpoint migration, and 3) delta formation in Lake Thun. In doing this we build confidence in the model and gain understanding of how the river system responded to anthropogenic perturbations.

UAS-SfM for coastal research: Geomorphic feature extraction and land cover classification from high-resolution elevation and optical imagery

USGS Publications Warehouse

Sturdivant, Emily; Lentz, Erika; Thieler, E. Robert; Farris, Amy; Weber, Kathryn; Remsen, David P.; Miner, Simon; Henderson, Rachel

2017-01-01

The vulnerability of coastal systems to hazards such as storms and sea-level rise is typically characterized using a combination of ground and manned airborne systems that have limited spatial or temporal scales. Structure-from-motion (SfM) photogrammetry applied to imagery acquired by unmanned aerial systems (UAS) offers a rapid and inexpensive means to produce high-resolution topographic and visual reflectance datasets that rival existing lidar and imagery standards. Here, we use SfM to produce an elevation point cloud, an orthomosaic, and a digital elevation model (DEM) from data collected by UAS at a beach and wetland site in Massachusetts, USA. We apply existing methods to (a) determine the position of shorelines and foredunes using a feature extraction routine developed for lidar point clouds and (b) map land cover from the rasterized surfaces using a supervised classification routine. In both analyses, we experimentally vary the input datasets to understand the benefits and limitations of UAS-SfM for coastal vulnerability assessment. We find that (a) geomorphic features are extracted from the SfM point cloud with near-continuous coverage and sub-meter precision, better than was possible from a recent lidar dataset covering the same area; and (b) land cover classification is greatly improved by including topographic data with visual reflectance, but changes to resolution (when <50 cm) have little influence on the classification accuracy.

Distribution and nature of UV absorbers on Trition's surface

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1995-01-01

Substantial evidence suggests that a UV (ultraviolet) Spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAM's exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SAM material. We hope to determine if UV-SAM's on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAM's has been determined, further constraints on their composition can be made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on Voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

Distribution and nature of UV absorbers on Triton's surface

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1995-01-01

Substantial evidence suggests that a UV spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAMs exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SaM material. We hope to determine if UV-SAMs on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAMs has been determined, further constraints on their composition cable made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

Distribution and nature of UV absorbers on Triton's surface

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1994-01-01

Substantial evidence suggests that a UV Spectrally Absorbing Material (UV-SAM) exists on Triton's surface. This evidence is found in the positive slope in Triton's spectrum from the UV to the near-IR, and the increasing contrast in Triton's light curve in the blue and UV. Although it is now widely-thought that UV-SAM's exist on Triton, little is known about their distribution and spectral properties. The goal of this NDAP Project is to determine the spatial distribution and geological context of the UV-SAM material. We hope to determine if UV-SAM's on Triton are correlated with geologic wind streaks, craters, calderas, geomorphic/topographic units, regions containing (or lacking) volatile frosts, or some other process (e.g., magnetospheric interactions). Once the location and distribution of UV-SAM's has been determined, further constraints on their composition can be made by analyzing the spectrographic data set. To accomplish these goals, various data sets will be used, including Voyager 2 UV and visible images of Triton's surface, IUE and HST spectra of Triton, and a geologic map of the surface based on Voyager 2 and spectrophotometric data. The results of this research will be published in the planetary science literature.

Lineaments of Texas - possible surface expressions of deep-seated phenomena. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodruff, C.M. Jr.; Caran, S.C.

1984-04-01

Lineaments were identified on 51 Landsat images covering Texas and parts of adjacent states in Mexico and the United States. A method of identifying lineaments was designed so that the findings would be consistent, uncomplicated, objective, and reproducible. Lineaments denoted on the Landsat images were traced onto 1:250,000-scale work maps and then rendered cartographically on maps representing each of the 51 Landsat images at a scale of 1:500,000. At this stage more than 31,000 lineaments were identified. It included significant areas outside of Texas. In preparing the final lineament map of Texas at 1:1,000,000-scale from the 1:500,000-scale maps, all featuresmore » that lay outside Texas and repetition among features perceived by individual workers were eliminated. Cultural features were checked for before reducing and cartographically fitting the mosaic of 51 individual map sheets to a single map base. Lineaments that were partly colinear but with different end points were modified into a single lineament trace with the combined length of the two or more colinear lineaments. Each lineament was checked to determine its validity according to our definition. The features were edited again to eliminate processing artifacts within the image itself, as well as representations of cultural features (fencelines, roads, and the like) and geomorphic patterns unrelated to bedrock structure. Thus the more than 31,000 lineaments originally perceived were reduced to the approximately 15,000 presented on the 1:1,000,000 map. Interpretations of the lineaments are presented.« less

Near-census Delineation of Laterally Organized Geomorphic Zones and Associated Sub-width Fluvial Landforms

NASA Astrophysics Data System (ADS)

Pasternack, G. B.; Hopkins, C.

2017-12-01

A river channel and its associated riparian corridor exhibit a pattern of nested, geomorphically imprinted, lateral inundation zones (IZs). Each zone plays a key role in fluvial geomorphic processes and ecological functions. Within each zone, distinct landforms (aka geomorphic or morphological units, MUs) reside at the 0.1-10 channel width scale. These features are basic units linking river corridor morphology with local ecosystem services. Objective, automated delineation of nested inundation zones and morphological units remains a significant scientific challenge. This study describes and demonstrates new, objective methods for solving this problem, using the 35-km alluvial lower Yuba River as a testbed. A detrended, high-resolution digital elevation model constructed from near-census topographic and bathymetric data was produced and used in a hypsograph analysis, a commonly used method in oceanographic studies capable of identifying slope breaks at IZ transitions. Geomorphic interpretation mindful of the river's setting was required to properly describe each IZ identified by the hypsograph analysis. Then, a 2D hydrodynamic model was used to determine what flow yields the wetted area that most closely matches each IZ domain. The model also provided meter-scale rasters of depth and velocity useful for MU mapping. Even though MUs are discharge-independent landforms, they can be revealed by analyzing their overlying hydraulics at low flows. Baseflow depth and velocity rasters are used along with a hydraulic landform classification system to quantitatively delineate in-channel bed MU types. In-channel bar and off-channel flood and valley MUs are delineated using a combination of hydraulic and geomorphic indicators, such as depth and velocity rasters for different discharges, topographic contours, NAIP imagery, and a raster of vegetation. The ability to objectively delineate inundation zones and morphological units in tandem allows for better informed river management and restoration strategies as well as scientific studies about abiotic-biotic linkages.

Scale-dependent geomorphic responses to active restoration and implications for cutthroat trout

NASA Astrophysics Data System (ADS)

Salant, N.; Miller, S. W.

2009-12-01

The predominant goal of instream habitat restoration is to increase the diversity, density and/or biomass of aquatic organisms through enhanced physical heterogeneity and increased food availability. In physically homogenized systems, habitat restoration is most commonly achieved at the reach-scale through the addition of structures or channel reconfiguration. Despite the completion of over 6,000 restoration projects in the United States, studies of fish responses to habitat restoration have largely produced equivocal results. Paradoxically, restoration monitoring overwhelmingly focuses on fish response without understanding how these responses link to the physical variables being altered and the scale at which geomorphic changes occur. Our study investigates whether instream habitat restoration affects geomorphic conditions at spatial scales relevant to the organism of interest (i.e. the spatial scale of the variables limiting to that organism). We measure the effects of active restoration on geomorphic metrics at three spatial scales (local, unit, and reach) using a before-after-control-impact design in a historically disturbed and heavily managed cutthroat trout stream. Observed trout habitat preferences (for spawning and juvenile/adult residence) are used to identify the limiting physical variables and are compared to the scale of spatially explicit geomorphic responses. Four reaches representing three different stages of restoration (before, one month and one year after) are surveyed for local-scale physical conditions, unit- and reach-scale morphology, resident fish use, and redd locations. Local-scale physical metrics include depth, nearbed and average velocity, overhead cover, particle size, and water quality metrics. Point measurements stratified by morphological unit are used to determine physical variability among unit types. Habitat complexity and availability are assessed at the reach-scale from topographic surveys and unit maps. Our multi-scale, process-based approach evaluates whether a commonly used restoration strategy creates geomorphic heterogeneity at scales relevant to fish diversity and microhabitat utilization, an understanding that will improve the efficiency and success of future restoration projects.

Riparian vegetation patterns in relation to fluvial landforms and channel evolution along selected rivers of Tuscany (Central Italy)

USGS Publications Warehouse

Hupp, C.R.; Rinaldi, M.

2007-01-01

Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, landforms, and processes are described and interpreted for selected rivers of Tuscany, Central Italy; with emphasis on channel evolution following human impacts. Field surveys were conducted along thirteen gauged reaches for species presence, fluvial landforms, and the type and amount of channel/riparian zone change. Inundation frequency of different geomorphic surfaces was determined, and vegetation data were analyzed using BDA (binary discriminate analysis) and DCA (detrended correspondence analysis) and related to hydrogeomorphology. Multivariate analyses revealed distinct quantitative vegetation patterns relative to six major fluvial geomorphic surfaces. DCA of the vegetation data also showed distinct associations of plants to processes of adjustment that are related to stage of channel evolution, and clearly separated plants along disturbance/landform/soil moisture gradients. Species richness increases from the channel bed to the terrace and on heterogeneous riparian areas, whereas species richness decreases from moderate to intense incision and from low to intense narrowing. ?? 2007 by Association of American Geographers.

Tectono-geomorphic indices of the Erin basin, NE Kashmir valley, India

NASA Astrophysics Data System (ADS)

Ahmad, Shabir; Alam, Akhtar; Ahmad, Bashir; Afzal, Ahsan; Bhat, M. I.; Sultan Bhat, M.; Farooq Ahmad, Hakim; Tectonics; Natural Hazards Research Group

2018-01-01

The present study aims to assess the tectonic activity in the Erin basin (NE Kashmir) on the basis of several relevant geomorphic indices and field observations. We use Digital Elevation Model (SRTM) and Survey of India (SoI) topographic maps in GIS environment to compute the geomorphic indices. The indices i.e., convex hypsometric curve, high hypsometric integral value (Hi > 0.5), low basin elongation ratio (Eb = 0.17), low mountain front sinuosity values (Smf = 1.08 average), low valley floor width ratios (Vf < 1), topographic assymetric character (T < 1), uneven basin asymmetry factor (AF < 50), elongated shape (Bs > 4) suggest that the area is tectonically active. Moreover, prominent irregularities (knickpoints/knickzones) along longitudinal profile of the Erin River even in homogenous resistant lithology (Panjal trap) and anomalous stream gradient index (SL) values reflect that the Erin basin is dissected by two faults (EF-1 and EF-2) with NNW-SSE and SSW-NNE trends respectively. The results of this preliminary study further substantiate the recent GPS studies, which argue that the maximum strain is accumulating in the NE part of the Kashmir Himalaya.

Geomorphology and failure history of the earthquake-induced Farmington Siding landslide complex, Davis County, Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, M.; Harty, K.M.

1993-04-01

The Farmington Siding landslide complex covers an area of 19.5 km[sup 2] in central Davis County. First identified and mapped in the 1970s, the feature was classified by previous researchers as a liquefaction-induced lateral spread based on surface geomorphology and exposures on the landslide complex. This was the first landslide in Utah to be attributed to earthquake-induced liquefaction. Geomorphic and geologic evidence indicate that the Farmington Sliding landslide complex likely consists of liquefaction-induced landslides that failed by means of both flow failure and lateral spreading. The landslide complex is located in an area underlain primarily by fine-grained deposits of Pleistocenemore » Lake Bonneville and Holocene Great Salt Lake. Geomorphic features of the landslide complex include main and minor scarps, hummocks, closed depressions, and transverse lineaments. The main scarp consists mostly of a series of arcuate scallops near the left flank of the landslide, but it is a relatively linear, single scarp near the right flank of the landslide. Hummocks and closed depressions are most common near the head region of the landslide complex. Failure of the Farmington Sliding landslide complex has occurred at least twice. The older, distal portion of the landslide complex is cut by the Gilbert shoreline of the Bonneville lake cycle, indicating that landsliding occurred more than 10,000 years ago. In the younger portion of the landslide complex, landsliding has disrupted the Gilbert shoreline. Radiocarbon age estimates from trenches on a hummock near the main scarp of the younger landslide indicate that slope failure occurred sometime between about 2,730 [+-] 370 cal. yr B.P. and 4,530 [+-] 300 cal. yr B.P., possibly during the penultimate or antepenultimate surface-faulting earthquake on the Weber segment of the Wasatch fault zone.« less

Sapping Features of the Colorado Plateau: a Comparative Planetary Geology Field Guide

NASA Technical Reports Server (NTRS)

Howard, Alan D. (Editor); Kochel, R. Craig (Editor); Holt, Henry E. (Editor)

1987-01-01

This book is an attempt to determine geomorphic criteria to be used to distinguish between channels formed predominantly by sapping and seepage erosion and those formed principally by surface runoff processes. The geologic nature of the Colorado Plateau has resulted in geomorphic features that show similarities to some areas on Mars, especially certain valley networks within thick sandstone formations. Where spring sapping is an effective process, the valleys that develop are unique in terms of their morphology and network pattern.

Influences of watershed geomorphology on extent and composition of riparian vegetation

Treesearch

Blake M. Engelhardt; Peter J. Weisberg; Jeanne C. Chambers

2011-01-01

Watershed (drainage basin) morphometry and geology were derived from digital data sets (DEMs and geologic maps). Riparian corridors were classified into five vegetation types (riparian forest, riparian shrub, wet/mesic meadow, dry meadow and shrub dry meadow) using high-resolution aerial photography. Regression and multivariate analyses were used to relate geomorphic...

Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Attachment 2, Geology report. Revised final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-12-01

Detailed investigations of geologic, geomorphic, and seismic conditions at the Bodo Canyon disposal site were conducted. The purpose of these investigations was basic site characterization and identification of potential geologic hazards that could affect long-term site stability. Subsequent engineering studies, such as analyses of hydrologic and liquefaction hazards, used the data developed in these studies. The geomorphic analysis was employed in the design of effective erosion protection. Studies of the regional and local seismotectonic setting, which included a detailed search for possible capable faults within a 65 kilometer radius of the site, provided the basis for seismic design parameters. Themore » scope of work performed included the following: Compilation and analysis of previous published and unpublished geologic literature and maps; Review of historical and instrumental earthquake data; Review of site-specific subsurface geologic data, including lithologic and geophysical logs of exploratory boreholes advanced in the site area; Photogeologic interpretations of existing conventional aerial photographs; and, Ground reconnaissance and mapping of the site region.« less

Calibration and Validation of Tundra Plant Functional Type Fractional Cover Mapping

NASA Astrophysics Data System (ADS)

Macander, M. J.; Nelson, P.; Frost, G. V., Jr.

2017-12-01

Fractional cover maps are being developed for selected tundra plant functional types (PFTs) across >500,000 sq. km of arctic Alaska and adjacent Canada at 30 m resolution. Training and validation data include a field-based training dataset based on point-intercept sampling method at hundreds of plots spanning bioclimatic and geomorphic gradients. We also compiled 50 blocks of 1-5 cm resolution RGB image mosaics in Alaska (White Mountains, North Slope, and Yukon-Kuskokwim Delta) and the Yukon Territory. The mosaics and associated surface and canopy height models were developed using a consumer drone and structure from motion processing. We summarized both the in situ measurements and drone imagery to determine cover of two PFTs: Low and Tall Deciduous Shrub, and Light Fruticose/Foliose Lichen. We applied these data to train 2 m (limited extent) and 30 m (wall to wall) maps of PFT fractional cover for shrubs and lichen. Predictors for 2 m models were commercial satellite imagery such as WorldView-2 and Worldview-3, analyzed on the ABoVE Science Cloud. Predictors for 30 m models were primarily reflectance composites and spectral metrics developed from Landsat imagery, using Google Earth Engine. We compared the performance of models developed from the in situ and drone-derived training data and identify best practices to improve the performance and efficiency of arctic PFT fractional cover mapping.

Application of Remote Sensing to Assess the Impact of Short Term Climate Variability on Coastal Sedimentation

NASA Technical Reports Server (NTRS)

Moeller, Christopher C.; Gunshor, Mathew M.; Menzel, W. Paul; Huh, Oscar K.; Walker, Nan D.; Rouse, Lawrence J.; Frey, Herbert V. (Technical Monitor)

2001-01-01

The University of Wisconsin and Louisiana State University have teamed to study the forcing of winter season cold frontal wind systems on sediment distribution patterns and geomorphology in the Louisiana coastal zone. Wind systems associated with cold fronts have been shown to modify coastal circulation and resuspend sediments along the microtidal Louisiana coast. The assessment includes quantifying the influence of cumulative winter season atmospheric forcing (through surface wind observations) from year to year in response to short term climate variability, such as El Nino events. A correlation between winter cyclone frequency and the strength of El Nino events has been suggested. The atmospheric forcing data are being correlated to geomorphic measurements along western Louisiana's prograding muddy coast. Remote sensing data is being used to map and track sediment distribution patterns for various wind conditions. Transferring a suspended sediment concentration (SSC) algorithm to EOS MODIS observations will enable estimates of SSC in case 2 waters over the global domain. Progress in Year 1 of this study has included data collection and analysis of wind observations for atmospheric forcing characterization, a field activity (TX-2001) to collect in situ water samples with co-incident remote sensing measurements from the NASA ER-2 based MODIS Airborne Simulator (MAS) and the EOS Terra based MODerate resolution Imaging Spectroradiometer (MODIS) instruments, aerial photography and of sediment burial pipe field measurements along the prograding muddy Chenier Plain coast of western Louisiana for documenting coastal change in that dynamic region, and routine collection of MODIS 250 in resolution data for monitoring coastal sediment patterns. The data sets are being used in a process to transfer an SSC estimation algorithm to the MODIS platform. Work is underway on assessing coastal transport for the winter 2000-01 season. Water level data for use in a Geomorphic Impact Index, which relates wind energy, water level conditions, and geomorphic change along the microtidal western Louisiana coastline is being assembled.

Geomorphic Controls on Aquifer Geometry in Northwestern India

NASA Astrophysics Data System (ADS)

van Dijk, W. M.; Densmore, A. L.; Sinha, R.; Gupta, S.; Mason, P. J.; Singh, A.; Joshi, S. K.; Nayak, N.; Kumar, M.; Shekhar, S.

2014-12-01

The Indo-Gangetic foreland basin suffers from one of the highest rates of groundwater extraction in the world, especially in the Indian states of Punjab, Haryana and Rajasthan. To understand the effects of this extraction on ground water levels, we must first understand the geometry and sedimentary architecture of the aquifer system, which in turn depend upon its geomorphic setting. We use satellite images and digital elevation models to map the geomorphology of the Sutlej and Yamuna river systems, while aquifer geometry is assessed using ~250 wells that extend to ~300 m depth in Punjab and Haryana. The Sutlej and Yamuna rivers have deposited large sedimentary fans at their outlets. Elongate downslope ridges on the fan surfaces form distributary networks that radiate from the Sutlej and Yamuna fan apices, and we interpret these ridges as paleochannel deposits associated with discrete fan lobes. Paleochannels picked out by soil moisture variations illustrate a complex late Quaternary history of channel avulsion and incision, probably associated with variations in monsoon intensity. Aquifer bodies on the Sutlej and Yamuna fans have a median thickness of 7 and 6 m, respectively, and follow a heavy-tailed distribution, probably because of stacked sand bodies. The percentage of aquifer material in individual lithologs decreases downstream, although the exponent on the thickness distribution remains the same, indicating that aquifer bodies decrease in number down fan but do not thin appreciably. Critically, the interfan area between the Sutlej and Yamuna fans has thinner aquifers and a lower proportion of aquifer material, despite its proximal location. Our data show that the Sutlej and Yamuna fan systems form the major aquifer systems in this area, and that their geomorphic setting therefore provides a first-order control on aquifer distribution and geometry. The large spatial heterogeneity of the system must be considered in any future aquifer management scheme.

Quantitative analysis of terrain units mapped in the northern quarter of Venus from Venera 15/16 data

NASA Technical Reports Server (NTRS)

Schaber, G. G.

1991-01-01

The contacts between 34 geological/geomorphic terrain units in the northern quarter of Venus mapped from Venera 15/16 data were digitized and converted to a Sinusoidal Equal-Area projection. The result was then registered with a merged Pioneer Venus/Venera 15/16 altimetric database, root mean square (rms) slope values, and radar reflectivity values derived from Pioneer Venus. The resulting information includes comparisons among individual terrain units and terrain groups to which they are assigned in regard to percentage of map area covered, elevation, rms slopes, distribution of suspected craters greater than 10 km in diameter.

Preliminary Surficial Geologic Map of the Mesquite Lake 30' X 60' Quadrangle, California and Nevada

USGS Publications Warehouse

Schmidt, Kevin M.; McMackin, Matthew

2006-01-01

The Quaternary surficial geologic map of the Mesquite Lake, California-Nevada 30'X60' quadrangle depicts deposit age and geomorphic processes of erosion and deposition, as identified by a composite of remote sensing investigations, laboratory analyses, and field work, in the arid to semi-arid Mojave Desert area, straddling the California-Nevada border. Mapping was motivated by the need to address pressing scientific and social issues such as understanding and predicting the effects of climate and associated hydrologic changes, human impacts on landscapes, ecosystem function, and natural hazards at a regional scale. As the map area lies just to the south of Las Vegas, Nevada, a rapidly expanding urban center, land use pressures and the need for additional construction materials are forecasted for the region. The map contains information on the temporal and spatial patterns of surface processes and hazards that can be used to model specific landscape applications. Key features of the geologic map include: (1) spatially extensive Holocene alluvial deposits that compose the bulk of Quaternary units (~25%), (2) remote sensing and field studies that identified fault scarps or queried faults in the Kingston Wash area, Shadow Mountains, southern Pahrump Valley, Bird Spring Range, Lucy Gray Mountains and Piute Valley, (3) a lineament indicative of potential fault offset is located in Mesquite Valley, (4) active eolian dunes and sand ramps located on the east side of Mesquite, Ivanpah, and Hidden Valleys adjacent to playas, (4) groundwater discharge deposits in southern Pahrump Valley, Spring Mountains, and Lucy Gray Mountains and (5) debris-flow deposits spanning almost the entire Quaternary period in age.

Zoogeomorphology in the Anthropocene

NASA Astrophysics Data System (ADS)

Butler, David R.

2018-02-01

The Anthropocene embodies the concept of human impacts on the natural environment, but disagreements exist as to when to identify its inception/starting date. In this paper I illustrate that regardless of the proposed starting date of the Anthropocene, important zoogeomorphic impacts were initiated at each of these proposed starting dates. Humans have profoundly altered geomorphic pathways through extinctions and the near-extirpation of native populations of animal species that strongly influenced hydrology and removal of surface sediment and through the introduction of populations of animals that bring to bear a suite of different geomorphic effects on environmental systems. Domestication of animals brought its own suite of zoogeomorphic implications. Introductions of exotic species, and the spread of feral species, often led to dramatic new geomorphic landscapes because of the absence of natural controls on population expansion. In the mountains of the western USA and elsewhere, the geomorphic actions of animals are being impacted by human-induced climate change. Climate change in some cases affects the spatial pattern and range of species, whereas in other cases it may lead to the extirpation of species with zoogeomorphic impacts.

Preliminary Geological Map of the Peace Vallis Fan Integrated with In Situ Mosaics From the Curiosity Rover, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Sumner, D. Y.; Palucis, M.; Dietrich, B.; Calef, F.; Stack, K. M.; Ehlmann, B.; Bridges, J.; Dromart, J.; Eigenbrode, J.; Farmer, J.;

Geomorphic evidence for ancient seas in west Deuteronilus Mensae, Mars-1: Regional geomorphology

NASA Technical Reports Server (NTRS)

Parker, Timothy J.; Schneeberger, Dale M.; Pieri, David C.; Saunders, R. Stephen

1987-01-01

The fretted terrain in west Deuteronilus Mensae consists of extensive cratered upland penninsulas or isolated plateaus cut by long, finger-like canyons typically 10 to 20 km wide and upwards of 300 km long. The longest of these canyons trend roughly north-south to north-northeast, which may reflect some local structural and/or topographic control. At least three geomorphic zones roughly parallel to the lowland/upland boundary, suggestive of increasing modification northward, can be recognized on the fretted region of the region. The southern-most zone (zone A) consists of sharply defined fretted terrain. The middle zone (zone B) consists of well defined fretted terrain in which the plateau surfaces appear smoother, with a somewhat darker and much less varied albedo surface than those of zone A. The northern-most zone (zone C) consists of rounded or softened fretted terrain. The zones were interpreted as surface exposures of successively lower stratigraphic units.

Evaluation of EREP techniques for geological mapping. [southern Pyrenees and Ebro basin in Spain

NASA Technical Reports Server (NTRS)

Vandermeermohr, H. E. C.; Srivastava, G. S. (Principal Investigator)

1975-01-01

The author has identified the following significant results. Skylab photographs may be successfully utilized for preparing a reconnaissance geological map in the areas where no maps or semi-detailed maps exist. Large coverage of area and regional perspective from Skylab photographs can help better coordination in regional mapping. It is possible to delineate major structural trends and other features like mega-lineaments, geofractures, and faults, which have evaded their detection by conventional methods. The photointerpretability is better in areas dominated by sedimentary rocks. Rock units of smaller extent and having poor geomorphic expressions are difficult to map. Demarcation of quaternary river alluvium can be made with better precision and ease with the Skylab photographs. Stereoscopic viewing greatly helps in interpretation of area structures. Skylab photographs are not good for preparing geological maps larger than 1:270,000 scale.

UAV and SfM in Detailed Geomorphological Mapping of Granite Tors: An Example of Starościńskie Skały (Sudetes, SW Poland)

NASA Astrophysics Data System (ADS)

Kasprzak, Marek; Jancewicz, Kacper; Michniewicz, Aleksandra

2017-11-01

The paper presents an example of using photographs taken by unmanned aerial vehicles (UAV) and processed using the structure from motion (SfM) procedure in a geomorphological study of rock relief. Subject to analysis is a small rock city in the West Sudetes (SW Poland), known as Starościńskie Skały and developed in coarse granite bedrock. The aims of this paper were, first, to compare UAV/SfM-derived data with the cartographical image based on the traditional geomorphological field-mapping methods and the digital elevation model derived from airborne laser scanning (ALS). Second, to test if the proposed combination of UAV and SfM methods may be helpful in recognizing the detailed structure of granite tors. As a result of conducted UAV flights and digital image post-processing in AgiSoft software, it was possible to obtain datasets (dense point cloud, texture model, orthophotomap, bare-ground-type digital terrain model—DTM) which allowed to visualize in detail the surface of the study area. In consequence, it was possible to distinguish even the very small forms of rock surface microrelief: joints, aplite veins, rills and karren, weathering pits, etc., otherwise difficult to map and measure. The study includes also valorization of particular datasets concerning microtopography and allows to discuss indisputable advantages of using the UAV/SfM-based DTM in geomorphic studies of tors and rock cities, even those located within forest as in the presented case study.

Alaskan Permafrost Analogs of Martian Small Valley Networks, Thermokarst, Terrain Softening, Terraces, and Volcanic Craters

NASA Technical Reports Server (NTRS)

Kargel, Jeffrey S.; Wessels, Rick; Beget, James E.; Eddy, Thomas; Lloyd, Sandra; Macaulay, Don; Proch, Mark; Skinner, Jim; Tanaka, Kenneth L.

2004-01-01

A geomorphic landscape analog in the Bering Land Bridge National Preserve (Alaska) offers a model for Mars where (1) fluvial and alluvial deposition, volcanism, and other processes first produced a layered ice-rich upper crust, and then (2) severe permafrost conditions (mild by today's Martian standards) and heterogeneous heat flow and volcanism have modified this terrain to produce a geomorphic areal mosaic that is alternately dominated by (a) geothermal meltwater and sublimation (bottom-up heat flow) and (b) surface-driven meltwater and sublimation (top-down heat flow).

Influence of flow variability on floodplain formation and destruction, Little Missouri River, North Dakota

USGS Publications Warehouse

Miller, J.R.; Friedman, J.M.

2009-01-01

Resolving observations of channel change into separate planimetric measurements of floodplain formation and destruction reveals distinct relations between these processes and the flow regime. We analyzed a time sequence of eight bottomland images from 1939 to 2003 along the Little Missouri River, North Dakota, to relate geomorphic floodplain change to flow along this largely unregulated river. At the decadal scale, floodplain formation and destruction varied independently. Destruction was strongly positively correlated with the magnitude of infrequent high flows that recur every 5-10 yr, whereas floodplain formation was negatively correlated with the magnitude of frequent low flows exceeded 80% of the time. At the century scale, however, a climatically induced decrease in peak flows has reduced the destruction rate, limiting the area made available for floodplain formation. The rate of destruction was not uniform across the floodplain. Younger surfaces were consistently destroyed at a higher rate than older surfaces, suggesting that throughput of contaminants would have occurred more rapidly than predicted by models that assume uniform residence time of sediment across the floodplain. Maps of floodplain ages produced by analysis of sequential floodplain images are similar to maps of forest ages produced through dendrochronology, confirming the assumption of dendrogeomorphic studies that riparian tree establishment in this system is limited to recent channel locations. ?? 2009 Geological Society of America.

Controls on morphological variability and role of stream power distribution pattern, Yamuna River, western India

NASA Astrophysics Data System (ADS)

Bawa, Nupur; Jain, Vikrant; Shekhar, Shashank; Kumar, Niraj; Jyani, Vikas

2014-12-01

Understanding the controls on the morphological variability of river systems constitutes one of the fundamental questions in geomorphic investigation. Channel morphology is an important indicator of river processes and is of significance for mapping the hydrology-ecologic connectivity in a river system and for predicting the future trajectory of river health in response to external forcings. This paper documents the spatial morphological variability and its natural and anthropogenic controls for the Yamuna River, a major tributary of the Ganga River, India. The Yamuna River runs through a major urban centre i.e. Delhi National Capital Region. The Yamuna River was divided into eight geomorphically distinct reaches on the basis of the assemblages of geomorphic units and the association of landscape, valley and floodplain settings. The morphological variability was analysed through stream power distribution and sediment load data at various stations. Stream power distribution of the Yamuna River basin is characterised by a non-linear pattern that was used to distinguish (a) high energy ‘natural' upstream reaches, (b) ‘anthropogenically altered', low energy middle stream reaches, and (c) ‘rejuvenated' downstream reaches again with higher stream power. The relationship between stream power and channel morphology in these reaches was integrated with sediment load data to define the maximum flow efficiency (MFE) as the threshold for geomorphic transition. This analysis supports the continuity of river processes and the significance of a holistic, basin-scale approach rather than isolated local scale analysis in river studies.

Rapid geomorphic change caused by glacial outburst floods and debris flows along Tahoma Creek, Mount Rainier, Washington, USA

USGS Publications Warehouse

Walder, J.S.; Driedger, C.L.

1994-01-01

As part of a hazards-assessment study, we examined the nature and rate of geomorphic change caused by outburst floods and debris flows along Tahoma Creek. Mount Rainier, since 1967. Archival aerial photographs of the area proved to be a rich source of qualitative geomorphic information. On the basis of limited direct evidence and considerations of stream hydrology, we conclude that nearly all of these debris flows began as outburst floods from South Tahoma Glacier. The water floods transformed to debris flows by incorporating large masses of sediment in a 2-km-long channel reach where the stream has incised proglacial sediments and debris-rich, stagnant glacier ice. Comparison of topographic maps for 1970 and 1991 shows that the average sediment flux out of the incised reach has been about 2 to 4 × 105 m3 a-1 corresponding to an average denudation rate in the upper part of the Tahoma Creek drainage basin of about 20 to 40 mm a-1, a value exceeded only rarely in basins affected by debris flows. However, little of this sediment has yet passed out of the Tahoma Creek basin. Comparison of geomorphic change at Tahoma Creek to that in two other alpine basins affected by outburst floods suggests that debris-rich stagnant ice can be an important source of sediment for debris flows as long as floods are frequent or channel slope is great.

Natural and human forcing in recent geomorphic change; case studies in the Rio de la Plata basin.

PubMed

Bonachea, Jaime; Bruschi, Viola M; Hurtado, Martín A; Forte, Luis M; da Silva, Mario; Etcheverry, Ricardo; Cavallotto, José L; Dantas, Marcilene F; Pejon, Osni J; Zuquette, Lázaro V; Bezerra, Maria Angélica de O; Remondo, Juan; Rivas, Victoria; Gómez-Arozamena, José; Fernández, Gema; Cendrero, Antonio

2010-06-01

An analysis of geomorphic system's response to change in human and natural drivers in some areas within the Río de la Plata basin is presented. The aim is to determine whether an acceleration of geomorphic processes has taken place in recent years and, if so, to what extent it is due to natural (climate) or human (land-use) drivers. Study areas of different size, socio-economic and geomorphic conditions have been selected: the Río de la Plata estuary and three sub-basins within its watershed. Sediment cores were extracted and dated ((210)Pb) to determine sedimentation rates since the end of the 19th century. Rates were compared with time series on rainfall as well as human drivers such as population, GDP, livestock load, crop area, energy consumption or cement consumption, all of them related to human capacity to disturb land surface. Data on river discharge were also gathered. Results obtained indicate that sedimentation rates during the last century have remained essentially constant in a remote Andean basin, whereas they show important increases in the other two, particularly one located by the São Paulo metropolitan area. Rates in the estuary are somewhere in between. It appears that there is an intensification of denudation/sedimentation processes within the basin. Rainfall remained stable or varied very slightly during the period analysed and does not seem to explain increases of sedimentation rates observed. Human drivers, particularly those more directly related to capacity to disturb land surface (GDP, energy or cement consumption) show variations that suggest human forcing is a more likely explanation for the observed change in geomorphic processes. It appears that a marked increase in denudation, of a "technological" nature, is taking place in this basin and leading to an acceleration of sediment supply. This is coherent with similar increases observed in other regions. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Active tectonics in the Mygdonia basin (northern Greece): a combined seismological and remote-sensed geomorphology approach

NASA Astrophysics Data System (ADS)

Gkarlaouni, Charikleia; Andreani, Louis; Pennos, Chris; Gloaguen, Richard; Papadimitriou, Eleftheria; Kilias, Adamantios; Michail, Maria

2014-05-01

In Greek mainland, active extensional deformation resulted in the development of numerous seismogenic E- to SE-trending basins. The Mygdonia graben located in central Macedonia produced major historical earthquakes and poses a serious threat to the neighbouring city of Thessaloniki. Our aim is to determine which active seismic sources have the potential to generate strong events. Active tectonics shape the landscape, control the evolution of the fluvial network and cause the occurrence of strong and frequent earthquakes generated by fault populations. Thus, our approach combined both seismology and remote-sensed geomorphology. Seismological investigation and more especially relocation analysis was performed for recent seismicity in the area (2000-2012). Low magnitude earthquakes not exceeding 4.8 constitute the seismicity pattern for this period. Accurately determined focal parameters indicate that seismicity is not only localized along major fault zones. Smaller faults seem also to be activated. Temporal and spatial investigation show that seismicity is clustered and seismic bursts often migrate to adjacent faults. The hypocentral distribution of precisely determined microearthquake foci reveals the existence of high-angle (> 60º) normal faults dipping both south and north. This is consistent with fault plane solutions of stronger earthquakes. The largest amount of earthquakes is generated along the NW-SE sub-basin bounded from "Assiros-Analipsi" and "Lagina" fault zone, as well as in "Sochos" fault in the north which dips with approximately 70º-80º to the south. All these structures played an important role in the seismotectonic evolution of the area. We used geomorphic indices in order to analyse the landscapes of the Mygdonia region. Geomorphic indices were derived from DEM and computed using MATLAB scripts. We classified the landscapes according to their erosional stages using hypsometric integral and surface roughness. Both indices suggest stronger erosion along the southern flank of the Mygdonia graben. Observed differences may be related to a diachronic evolution. River profiles crossing the Thessaloniki-Gerakarou fault system (TGFS) south of the Mygdonia basin display anomalies such as knickpoints or convex segments. These anomalies reflect significant changes in river base-levels possibly triggered by uplift/subsidence processes. We also computed the normalized steepness index (ksn) for concave segments in rivers. We observe an increase of ksn values towards the south while the lithology remains almost constant. These changes in ksn values may be thus related to an increase in deformation rates along the southern TGFS. Our geomorphic analysis also highlighted several flat paleo-surfaces located on top of main ranges at elevations comprised between 300 and 450m above the basin infill. Finally, we produced thematic maps combining present-day seismicity, historical earthquakes and geomorphic features derived from DEM. The combined use of both seismology and remote-sensed geomorphology allowed us to better understand the at-depth and surface expressions of active structures within the Mygdonia basin. It also provided further insights into the tectonic evolution of the study area. This project is funded by the German Academic Exchange Service (DAAD) and the Greek State Scholarschips Foundation (IKY) under the IKYDA initiative.

Inference of Eco-geomorphic Processes Using Integrated Historical Data for a Rapidly Changing Mediterranean-climate River Corridor: Lower Santa Clara River, California

NASA Astrophysics Data System (ADS)

Beller, E. E.; Grossinger, R. M.; Downs, P. W.; Orr, B. K.

2010-12-01

Environmental conservation demands reach-specific data as the basis for place-based restoration and management measures. However, areas such as the lower Santa Clara River valley have been subject to intensive modification since the at least the nineteenth century, but without regular hydrogeomorphic or ecological monitoring (e.g., flow gauging, repeat topographic surveys, vegetation mapping) until the mid-twentieth century. This gap has limited data on former river corridor form and understanding of historical eco-geomorphic processes. The result is a lack of consensus about the range of potential riparian and aquatic habitats to consider as restoration targets, their appropriate relative distribution, and the relationship between such ecological targets and physical processes on the river, past and present. To address this data gap on the lower Santa Clara River, we initiated an effort to extend the documentation of river characteristics beyond readily available early data sets (such as aerial photography from 1927) by integrating historical cartographic, textual, and visual accounts to create a heterogeneous but substantial dataset describing hydrologic, geomorphic, and riparian characteristics back to 1769 - the date of the first non-native exploration of the region. We collected over 1,000 documents, including General Land Office survey data, early maps from the county surveyor, and traveler’s accounts of the region, evaluating each source for its accuracy and reliability. These data were synthesized to evaluate the location and composition of riparian areas that persisted despite substantial flood events and impacts of rapidly changing land use, and to determine aspects of the former hydrology of the river affecting riparian pattern that are still relevant today. The data also indicate the general resilience of mainstem channel form in response to these events in contrast to the present-day eco-geomorphic system, which is far more sensitive to change. Used with caution, such historical data can help scientists and managers better contextualize contemporary processes on the river, and so provide informed decisions about the river’s future.

Geomorphic evidence of Quaternary tectonics within an underlap fault zone of southern Apennines, Italy

NASA Astrophysics Data System (ADS)

Giano, Salvatore Ivo; Pescatore, Eva; Agosta, Fabrizio; Prosser, Giacomo

2018-02-01

A composite seismic source, the Irpinia - Agri Valley Fault zone, located in the axial sector of the fold-and-thrust belt of southern Apennines, Italy, is investigated. This composite source is made up of a series of nearly parallel, NW-striking normal fault segments which caused many historical earthquakes. Two of these fault segments, known as the San Gregorio Magno and Pergola-Melandro, and the fault-related mountain fronts, form a wedge-shaped, right-stepping, underlap fault zone. This work is aimed at documenting tectonic geomorphology and geology of this underlap fault zone. The goal is to decipher the evidence of surface topographic interaction between two bounding fault segments and their related mountain fronts. In particular, computation of geomorphic indices such as mountain front sinuosity (Smf), water divide sinuosity (Swd), asymmetry factor (AF), drainage basin elongation (Bs), relief ratio (Rh), Hypsometry (HI), normalized steepness (Ksn), and concavity (θ) is integrated with geomorphological analysis, the geological mapping, and structural analysis in order to assess the recent activity of the fault scarp sets recognized within the underlap zone. Results are consistent with the NW-striking faults as those showing the most recent tectonic activity, as also suggested by presence of related slope deposits younger than 38 ka. The results of this work therefore show how the integration of a multidisciplinary approach that combines geomorphology, morphometry, and structural analyses may be key to solving tectonic geomorphology issues in a complex, fold-and-thrust belt configuration.

Spatial heterogeneity of within-stream methane concentrations

NASA Astrophysics Data System (ADS)

Crawford, John T.; Loken, Luke C.; West, William E.; Crary, Benjamin; Spawn, Seth A.; Gubbins, Nicholas; Jones, Stuart E.; Striegl, Robert G.; Stanley, Emily H.

2017-05-01

Streams, rivers, and other freshwater features may be significant sources of CH4 to the atmosphere. However, high spatial and temporal variabilities hinder our ability to understand the underlying processes of CH4 production and delivery to streams and also challenge the use of scaling approaches across large areas. We studied a stream having high geomorphic variability to assess the underlying scale of CH4 spatial variability and to examine whether the physical structure of a stream can explain the variation in surface CH4. A combination of high-resolution CH4 mapping, a survey of groundwater CH4 concentrations, quantitative analysis of methanogen DNA, and sediment CH4 production potentials illustrates the spatial and geomorphic controls on CH4 emissions to the atmosphere. We observed significant spatial clustering with high CH4 concentrations in organic-rich stream reaches and lake transitions. These sites were also enriched in the methane-producing mcrA gene and had highest CH4 production rates in the laboratory. In contrast, mineral-rich reaches had significantly lower concentrations and had lesser abundances of mcrA. Strong relationships between CH4 and the physical structure of this aquatic system, along with high spatial variability, suggest that future investigations will benefit from viewing streams as landscapes, as opposed to ecosystems simply embedded in larger terrestrial mosaics. In light of such high spatial variability, we recommend that future workers evaluate stream networks first by using similar spatial tools in order to build effective sampling programs.

Abandoned floodplain plant communities along a regulated dryland river

USGS Publications Warehouse

Reynolds, L. V.; Shafroth, Patrick B.; House, P. K.

2014-01-01

Rivers and their floodplains worldwide have changed dramatically over the last century because of regulation by dams, flow diversions and channel stabilization. Floodplains no longer inundated by river flows following dam-induced flood reduction comprise large areas of bottomland habitat, but the effects of abandonment on plant communities are not well understood. Using a hydraulic flow model, geomorphic mapping and field surveys, we addressed the following questions along the Bill Williams River, Arizona: (i) What per cent of the bottomland do abandoned floodplains comprise? and (ii) Are abandoned floodplains quantitatively different from adjacent xeric and riparian surfaces in terms of vegetation composition and surface sediment? We found that nearly 70% of active channel and floodplain area was abandoned following dam installation. Abandoned floodplains along the Bill Williams River tend to be similar to each other yet distinct from neighbouring habitats: they have been altered physically from their historic state, leading to distinct combinations of surface sediments, hydrology and plant communities. Abandoned floodplains may transition to xeric communities over time but are likely to retain some riparian qualities as long as there is access to relatively shallow ground water. With expected increases in water demand and drying climatic conditions in many regions, these surfaces and associated vegetation will continue to be extensive in riparian landscapes worldwide

Recently active traces of the Bartlett Springs Fault, California: a digital database

USGS Publications Warehouse

Lienkaemper, James J.

2010-01-01

The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Bartlett Springs Fault Zone, California. The location and recency of the mapped traces is primarily based on geomorphic expression of the fault as interpreted from large-scale aerial photography. In a few places, evidence of fault creep and offset Holocene strata in trenches and natural exposures have confirmed the activity of some of these traces. This publication is formatted both as a digital database for use within a geographic information system (GIS) and for broader public access as map images that may be browsed on-line or download a summary map. The report text describes the types of scientific observations used to make the map, gives references pertaining to the fault and the evidence of faulting, and provides guidance for use of and limitations of the map.

Bend-scale geomorphic classification and assessment of the Lower Missouri River from Sioux City, Iowa, to the Mississippi River for application to pallid sturgeon management

USGS Publications Warehouse

Jacobson, Robert B.; Colvin, Michael E.; Bulliner, Edward A.; Pickard, Darcy; Elliott, Caroline M.

2018-06-07

Management actions intended to increase growth and survival of pallid sturgeon (Scaphirhynchus albus) age-0 larvae on the Lower Missouri River require a comprehensive understanding of the geomorphic habitat template of the river. The study described here had two objectives relating to where channel-reconfiguration projects should be located to optimize effectiveness. The first objective was to develop a bend-scale (that is, at the scale of individual bends, defined as “cross-over to cross-over”) geomorphic classification of the Lower Missouri River to help in the design of monitoring and evaluation of such projects. The second objective was to explore whether geomorphic variables could provide insight into varying capacities of bends to intercept drifting larvae. The bend-scale classification was based on geomorphic and engineering variables for 257 bends from Sioux City, Iowa, to the confluence with the Mississippi River near St. Louis, Missouri. We used k-means clustering to identify groupings of bends that shared the same characteristics. Separate 3-, 4-, and 6-cluster classifications were developed and mapped. The three classifications are nested in a hierarchical structure. We also explored capacities of bends to intercept larvae through evaluation of linear models that predicted persistent sand area or catch per unit effort (CPUE) of age-0 sturgeon as a function of the same geomorphic variables used in the classification. All highly ranked models that predict persistent sand area contained mean channel width and standard deviation of channel width as significant variables. Some top-ranked models also included contributions of channel sinuosity and density of navigation structures. The sand-area prediction models have r-squared values of 0.648–0.674. In contrast, the highest-ranking CPUE models have r-squared values of 0.011–0.170, indicating much more uncertainty for the biological response variable. Whereas the persistent sand model documents that physical processes of transport and accumulation are systematic and predictable, the poor performance of the CPUE models indicate that additional processes will need to be considered to predict biological transport and accumulation.

Geomorphic controls on salmon nesting patterns described by a new, narrow-beam terrestrial-aquatic lidar

Treesearch

Jim A. McKean; Dan J. Isaak; Charles W. Wright

2008-01-01

Riverine aquatic biodiversity is rapidly being lost worldwide, but preservation efforts are hampered, in part because studies of these dynamic environments are limited by cost and logistics to small local surveys. Full understanding of stream ecosystems requires precise, high-resolution mapping of entire stream networks and adjacent landforms. We use a narrow-beam,...

Kinematic Slip Model for 12 May 2008 Wenchuan-Beichuan Mw 7.9 Earthquake from Joint Inversion of ALOS, Envisat, and Teleseismic Data

NASA Technical Reports Server (NTRS)

Fielding, Eric; Sladen, Anthony; Avouac, Jean-Philippe; Li, Zhenhong; Ryder, Isabelle; Burgmann, Roland

2008-01-01

The presentations explores kinematics of the Wenchaun-Beichuan earthquake using data from ALOS, Envisat, and teleseismic recordings. Topics include geomorphic mapping, ALOS PALSAR range offsets, ALOS PALSAR interferometry, Envisat IM interferometry, Envisat ScanSAR, Joint GPS-InSAR inversion, and joint GPS-teleseismic inversion (static and kinematic).

Kasei Vallis of Mars: Dating the Interplay of Tectonics and Geomorphology

NASA Technical Reports Server (NTRS)

Wise, D. U.

1985-01-01

Crater density age dates on more than 250 small geomorphic surfaces in the Kasei Region of Mars show clusterings indicative of times of peak geomorphic and tectonic activity. Kasei Vallis is part of a 300 km wide channel system breaching a N-S trending ancient basement high (+50,000 crater age) separating the Chryse Basin from the Tharsis Volcanic Province of Mars. The basement high was covered by a least 3 groups of probable volcanic deposits. Major regional fracturing took place at age 4,000 to 5,000 and was immediately followed by deposition of regional volcanics of the Fesenkov Plains (age 3,000 to 4,200). Younger clusterings of dates in the 900 to 1,500 and 500 to 700 range represent only minor modification of the basic tectonic geomorphic landform. The data suggest that Kasei gap is a structurally controlled breach of a buried ridge by a rather brief episode of fluvial activity.

Influences of Geomorphic Complexity and Rehabilitation on Nutrient Uptake in an Urban Stream

NASA Astrophysics Data System (ADS)

Mueller, J. S.; Baker, D. W.; Bledsoe, B. P.

2006-12-01

Headwater streams, which are highly vulnerable to anthropogenic impacts associated with land use change, have large surface-to-volume ratios that favor retention and removal of nitrogen. We describe a study focused on how geomorphic complexity is related to nutrient retention in impacted and restored headwater streams along a gradient of human land use. A key element of the study is a detailed protocol for characterizing the spatial distribution of physical habitat units composed of relatively distinct combinations of flow hydraulics and textural facies. We are using the detailed physical characterization and nutrient injections in paired segments of a Colorado Front Range urban stream to examine associations among geomorphic complexity, nitrogen uptake, and the degree and style of channel rehabilitation. The results of the study have implications for the viability of stream rehabilitation as a tool for reducing N delivery to downstream aquatic systems that are vulnerable to eutrophication.

Relation of urbanization to stream habitat and geomorphic characteristics in nine metropolitan areas of the United States

USGS Publications Warehouse

Fitzpatrick, Faith A.; Peppler, Marie C.

2010-01-01

The relation of urbanization to stream habitat and geomorphic characteristics was examined collectively and individually for nine metropolitan areas of the United States?Portland, Oregon; Salt Lake City, Utah; Denver, Colorado; Dallas?Forth Worth, Texas; Milwaukee?Green Bay, Wisconsin; Birmingham, Alabama; Atlanta, Georgia; Raleigh, North Carolina; and Boston, Massachusetts. The study was part of a larger study conducted by the U.S. Geological Survey from 1999 to 2004 to examine the effects of urbanization on the physical, chemical, and biological components of stream ecosystems. The objectives of the current study were to determine how stream habitat and geomorphic characteristics relate to different aspects of urbanization across a variety of diverse environmental settings and spatial scales. A space-for-time rural-to-urban land-cover gradient approach was used. Reach-scale habitat data and geomorphic characteristic data were collected once during low flow and included indicators of potential habitat degradation such as measures of channel geometry and hydraulics, streambed substrate, low-flow reach volume (an estimate of base-flow conditions), habitat complexity, and riparian/bank conditions. Hydrologic metrics included in the analyses were those expected to be altered by increases in impervious surfaces, such as high-flow frequency and duration, flashiness, and low-flow duration. Other natural and human features, such as reach-scale channel engineering, geologic setting, and slope, were quantified to identify their possible confounding influences on habitat relations with watershed-scale urbanization indicators. Habitat and geomorphic characteristics were compared to several watershed-scale indicators of urbanization, natural landscape characteristics, and hydrologic metrics by use of correlation analyses and stepwise linear regression. Habitat and geomorphic characteristics were related to percentages of impervious surfaces only in some metropolitan areas and environmental settings. The relations between watershed-scale indicators of urbanization and stream habitat depended on physiography and climate, hydrology, pre-urban channel alterations, reach-scale slope and presence of bedrock, and amount of bank stabilization and grade control. Channels increased in size with increasing percentages of impervious surfaces in southeastern and midwestern metropolitan areas regardless of whether the pre-existing land use was forest or agriculture. The amount of enlargement depended on annual precipitation and frequency of high-flow events. The lack of a relation between channel enlargement and increasing impervious surfaces in other metropolitan areas was thought to be confounded by pre-urbanization hydrologic and channel alterations. Direct relations of channel shape and streambed substrate to urbanization were variable or lacking, probably because the type, amount, and source of sediment are dependent on the phase of urbanization. Reach-scale slope also was important for determining variations in streambed substrate and habitat complexity (percentage of riffles and runs). Urbanization-associated changes in reach-scale riparian vegetation varied geographically, partially depending on pre-existing riparian vegetation characteristics. Bank erosion increased in Milwaukee?Green Bay and Boston urban streams, and bank erosion also increased with an increase in a streamflow flashiness index. However, potential relations likely were confounded by the frequent use of channel stabilization and bank protection in urban settings. Low-flow reach volume did not decrease with increasing urbanization, but instead was related to natural landscape characteristics and possibly other unmeasured factors. The presence of intermittent bedrock in some sampled reaches likely limited some geomorphic responses to urbanization, such as channel bed erosion. Results from this study emphasize the importance of including a wide range of landscape variables at m

Multidata remote sensing approach to regional geologic mapping in Venezuela

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.N.

1996-08-01

Remote Sensing played an important role in evaluating the exploration potential of selected lease blocks in Venezuela. Data sets used ranged from regional Landsat and airborne radar (SLAR) surveys to high-quality cloud-free air photos for local but largely inaccessible terrains. The resulting data base provided a framework for the conventional analyses of surface and subsurface information available to the project team. (1) Regional surface geology and major structural elements were interpreted from Landsat MSS imagery supplemented by TM and a regional 1:250,000 airborne radar (SLAR) survey. Evidence of dextral offset, en echelon folds and major thoroughgoing faults suggest a regionalmore » transpressional system modified by local extension and readjustment between small-scale crustal blocks. Surface expression of the major structural elements diminishes to the east, but can often be extended beneath the coastal plain by drainage anomalies and subtle geomorphic trends. (2) Environmental conditions were mapped using the high resolution airborne radar images which were used to relate vegetation types to surface texture and elevation; wetlands, outcrop and cultural features to image brightness. Additional work using multispectral TM or SPOT imagery is planned to more accurately define environmental conditions and provide a baseline for monitoring future trends. (3) Offshore oil seeps were detected using ERS-1 satellite radar (SAR) and known seeps in the Gulf of Paria as analogs. While partially successful, natural surfactants, wind shadow and a surprising variety of other phenomena created {open_quotes}false alarms{close_quotes} which required other supporting data and field sampling to verify the results. Key elements of the remote sensing analyses will be incorporated into a comprehensive geographic information (GIS) which will eventually include all of Venezuela.« less

A Mid-Latitude Geomorphologic Map of Titan

NASA Astrophysics Data System (ADS)

Lopes, Rosaly M. C.; Malaska, Michael; Schoenfeld, Ashley; Solomonidou, Anezina; Birch, Samuel; Hayes, Alexander; Williams, David A.; Janssen, Michael A.; Le Gall, Alice; Turtle, Elizabeth P.; Radebaugh, Jani; Cassini RADAR Team

2016-10-01

We investigated the geologic history of Titan through mapping and analyzing the distribution of observed geomorphic features using a combination of Cassini data collected by RADAR, VIMS, and ISS. Determining the spatial and superposition relationships between geomorphologic units on Titan leads to an understanding of the likely time evolution of the landscape and gives insight into the process interactions that drive its evolution. We have used all available datasets to extend the mapping initially done by Lopes et al. [1]. We now have the mid-latitudes (60N to 60S) of Titan mapped at 1:800,000 scale in all areas covered by Synthetic Aperture Radar (SAR). A map of the polar regions has been done by Birch et al. [2]. For the mid-latitudes, we have defined five broad classes of terrains following Malaska et al. [3], largely based on prior mapping [1]. These broad classes are: craters, hummocky/mountainous, labyrinth, plains, and dunes. We have found that the hummocky/mountainous terrains are the oldest units on the surface and appear radiometrically cold, indicating icy materials [5]. Dunes are the youngest units and appear radiometrically warm, indicating organic sediments. VIMS analysis shows that compositional variations can also exist within the same class of unit [6, 7]. Future work aims to combine the polar maps of Birch et al. [2] with the mid-latitude maps presented here and harmonize the units at the 60 degrees boundaries. We also plan to extend the map in regions not covered by SAR to produce a 1:1,500,000 scale map compatible with USGS standards.References: [1] Lopes, R.M.C., et al.: Icarus, 205, 540-588, 2010; [2] Birch et al., submitted to Icarus. [3] Malaska, M., et al.: Icarus, 270, 130-161, 2016; [4] Barnes, J., et al.: Pl. Scie., 2:1, 2013; [5] Janssen et al., 2016 Icarus 270, 443-459, 2016. [6] Solomonidou, A., et al. : DPS abstract, 2016. [7] Lopes, R.M.C., et al, Icarus, 270, 162-182, 2016.

On the role of "internal variability" on soil erosion assessment

NASA Astrophysics Data System (ADS)

Kim, Jongho; Ivanov, Valeriy; Fatichi, Simone

2017-04-01

Empirical data demonstrate that soil loss is highly non-unique with respect to meteorological or even runoff forcing and its frequency distributions exhibit heavy tails. However, all current erosion assessments do not describe the large associated uncertainties of temporal erosion variability and make unjustified assumptions by relying on central tendencies. Thus, the predictive skill of prognostic models and reliability of national-scale assessments have been repeatedly questioned. In this study, we attempt to reveal that the high variability in soil losses can be attributed to two sources: (1) 'external variability' referring to the uncertainties originating at macro-scale, such as climate, topography, and land use, which has been extensively studied; (2) 'geomorphic internal variability' referring to the micro-scale variations of pedologic properties (e.g., surface erodibility in soils with multi-sized particles), hydrologic properties (e.g., soil structure and degree of saturation), and hydraulic properties (e.g., surface roughness and surface topography). Using data and a physical hydraulic, hydrologic, and erosion and sediment transport model, we show that the geomorphic internal variability summarized by spatio-temporal variability in surface erodibility properties is a considerable source of uncertainty in erosion estimates and represents an overlooked but vital element of geomorphic response. The conclusion is that predictive frameworks of soil erosion should embed stochastic components together with deterministic assessments, if they do not want to largely underestimate uncertainty. Acknowledgement: This study was supported by the Basic Science Research Program of the National Research Foundation of Korea funded by the Ministry of Education (2016R1D1A1B03931886).

Scaling considerations related to interactions of hydrologic, pedologic and geomorphic processes (Invited)

NASA Astrophysics Data System (ADS)

Sidle, R. C.

2013-12-01

Hydrologic, pedologic, and geomorphic processes are strongly interrelated and affected by scale. These interactions exert important controls on runoff generation, preferential flow, contaminant transport, surface erosion, and mass wasting. Measurement of hydraulic conductivity (K) and infiltration capacity at small scales generally underestimates these values for application at larger field, hillslope, or catchment scales. Both vertical and slope-parallel saturated flow and related contaminant transport are often influenced by interconnected networks of preferential flow paths, which are not captured in K measurements derived from soil cores. Using such K values in models may underestimate water and contaminant fluxes and runoff peaks. As shown in small-scale runoff plot studies, infiltration rates are typically lower than integrated infiltration across a hillslope or in headwater catchments. The resultant greater infiltration-excess overland flow in small plots compared to larger landscapes is attributed to the lack of preferential flow continuity; plot border effects; greater homogeneity of rainfall inputs, topography and soil physical properties; and magnified effects of hydrophobicity in small plots. At the hillslope scale, isolated areas with high infiltration capacity can greatly reduce surface runoff and surface erosion at the hillslope scale. These hydropedologic and hydrogeomorphic processes are also relevant to both occurrence and timing of landslides. The focus of many landslide studies has typically been either on small-scale vadose zone process and how these affect soil mechanical properties or on larger scale, more descriptive geomorphic studies. One of the issues in translating laboratory-based investigations on geotechnical behavior of soils to field scales where landslides occur is the characterization of large-scale hydrological processes and flow paths that occur in heterogeneous and anisotropic porous media. These processes are not only affected by the spatial distribution of soil physical properties and bioturbations, but also by geomorphic attributes. Interactions among preferential flow paths can induce rapid pore water pressure response within soil mantles and trigger landslides during storm peaks. Alternatively, in poorly developed and unstructured soils, infiltration occurs mainly through the soil matrix and a lag time exists between the rainfall peak and development of pore water pressures at depth. Deep, slow-moving mass failures are also strongly controlled by secondary porosity within the regolith with the timing of activation linked to recharge dynamics. As such, understanding both small and larger scale processes is needed to estimate geomorphic impacts, as well as streamflow generation and contaminant migration.

Drainage evolution in the debris avalanche deposits near Mount Saint Helens, Washington

NASA Technical Reports Server (NTRS)

Beach, G. L.; Dzurisin, D.

1984-01-01

The 18 May 1980 eruption of Mount St. Helens was initiated by a massive rockslide-debris avalanche which completely transformed the upper 25 km of the North Fork Toutle River valley. The debris was generated by one of the largest gravitational mass movements ever recorded on Earth. Moving at an average velocity of 35 m/s, the debris avalanche buried approximately 60 sq km of terrain to an average depth of 45 m with unconsolidated, poorly sorted volcaniclastic material, all within a period of 10 minutes. Where exposed and unaltered by subsequent lahars and pyroclastic flows, the new terrain surface was characterized predominantly by hummocks, closed depressions, and the absence of an identifiable channel network. Following emplacement of the debris avalanche, a complex interrelationship of fluvial and mass wasting processes immediately began operating to return the impacted area to an equilibrium status through the removal of material (potential energy) and re-establishment of graded conditions. In an attempt to chronicle the morphologic evolution of this unique environmental setting, a systematic series of interpretative maps of several selected areas was produced. These maps, which document the rate and character of active geomorphic processes, are discussed.

Airborne and spaceborne radar images for geologic and environmental mapping in the Amazon rain forest, Brazil

NASA Technical Reports Server (NTRS)

Hurtak, James J.; Ford, John P.

1986-01-01

Spaceborne and airborne radar image of portions of the Middle and Upper Amazon basin in the state of Amazonas and the Territory of Roraima are compared for purposes of geological and environmental mapping. The contrasted illumination geometries and imaging parameters are related to terrain slope and surface roughness characteristics for corresponding areas that were covered by each of the radar imaging systems. Landforms range from deeply dissected mountain and plateau with relief up to 500 m in Roraima, revealing ancient layered rocks through folded residual mountains to deeply beveled pediplain in Amazonas. Geomorphic features provide distinct textural signatures that are characteristic of different rock associations. The principle drainages in the areas covered are the Rio Negro, Rio Branco, and the Rio Japura. Shadowing effects and low radar sensitivity to subtle linear fractures that are aligned parallel or nearly parallel to the direction of radar illumination illustrate the need to obtain multiple coverage with viewing directions about 90 degrees. Perception of standing water and alluvial forest in floodplains varies with incident angle and with season. Multitemporal data sets acquired over periods of years provide an ideal method of monitoring environmental changes.

LiDAR-Assisted identification of an active fault near Truckee, California

USGS Publications Warehouse

Hunter, L.E.; Howle, J.F.; Rose, R.S.; Bawden, G.W.

2011-01-01

We use high-resolution (1.5-2.4 points/m2) bare-earth airborne Light Detection and Ranging (LiDAR) imagery to identify, map, constrain, and visualize fault-related geomorphology in densely vegetated terrain surrounding Martis Creek Dam near Truckee, California. Bare-earth LiDAR imagery reveals a previously unrecognized and apparently youthful right-lateral strike-slip fault that exhibits laterally continuous tectonic geomorphic features over a 35-km-long zone. If these interpretations are correct, the fault, herein named the Polaris fault, may represent a significant seismic hazard to the greater Truckee-Lake Tahoe and Reno-Carson City regions. Three-dimensional modeling of an offset late Quaternary terrace riser indicates a minimum tectonic slip rate of 0.4 ?? 0.1 mm/yr.Mapped fault patterns are fairly typical of regional patterns elsewhere in the northern Walker Lane and are in strong coherence with moderate magnitude historical seismicity of the immediate area, as well as the current regional stress regime. Based on a range of surface-rupture lengths and depths to the base of the seismogenic zone, we estimate a maximum earthquake magnitude (M) for the Polaris fault to be between 6.4 and 6.9.

Data mining of external and internal forcing of fluvial systems for catchment management: A case study on the Red River (Song Hong), Vietnam

NASA Astrophysics Data System (ADS)

Schmitt, Rafael; Bizzi, Simone; Castelletti, Andrea

2013-04-01

The understanding of river hydromorphological processes has been recognized in the last decades as a priority of modern catchment management, since interactions of natural and anthropogenic forces within the catchment drives fluvial geomorphic processes, which shape physical habitat, affect river infrastructures and influence freshwater ecological processes. The characterization of river hydromorphological features is commonly location and time specific and highly resource demanding. Therefore, its routine application at regional or national scales and the assessment of spatio-temporal changes as reaction to internal and external disturbances is rarely feasible at present. Information ranging from recently available high-resolution remote-sensing data (such as DEM), historic data such as land use maps or aerial photographs and monitoring networks of flow and rainfall, open up novel and promising capacity for basin-wide understanding of dominant hydromorphological drivers. Analysing the resulting multiparametric data sets in their temporal and spatial dimensions requires sophisticated data mining tools to exploit the potential of this information. We propose a novel framework that allows for the quantitative assessment of multiparametric data sets to identify classes of channel reaches characterized by similar geomorphic drivers using remote-sensing data and monitoring networks available in the catchment. This generic framework was applied to the Red River (Song Hong) basin, the second largest basin (87,800 sq.km) in Vietnam. Besides its economic importance, the river is experiencing severe river bed incisions due to recent construction of new dams in the upstream part of the catchment and sand mining in the surrounding of the capital city Hanoi. In this context, characterized by an high development rate, current efforts to increase water productivity and minimize impacts on the fluvial systems by means of focused infrastructure and management measures require a thorough understanding of the fluvial system and, in particular, basin-wide assessment of resilience to human-induced change. . The framework proposed has allowed producing high-dimensional samples of spatially distributed geomorphic drivers at catchment scale while integrating recent and historic point records for the Red River basin. This novel dataset has been then analysed using self-organizing maps (SOM) an artificial neural network model in combination with fuzzy clustering. The above framework is able to identify non-trivial correlations in driving forces and to derive a fuzzy classification at reach scale which represents continuities and discontinuities in the river systems. The use of the above framework allowed analyzing the spatial distribution of geomorphic features at catchment scale, revealing patterns of similarities and dissimilarities within the catchment and allowing a classification of river reaches characterized by similar geomorphic drivers, fluvial processes and response to external forcing. The paper proposes an innovative and promising technique to produce hydromorphological classifications at catchment scale integrating historical and recent available high resolution data. The framework aims at opening the way to a more structured organization and analyses of recently available information on river geomorphic features, so far often missing or rarely exploited. This approach poses the basis to produce efficient databases of river geomorphic features and processes related to natural and anthropogenic drivers. That is a necessity in order to enhance our understanding of the internal and external forces which drive fluvial systems, to assess the resilience and dynamic of river landscapes and to develop the more efficient river management strategies of the future.

Sediment Budget Analysis and Hazard Assessment in the Peynin, a Small Alpine Catchment (Upper Guil River, Southern Alps, France)

NASA Astrophysics Data System (ADS)

Carlier, Benoit; Arnaud-Fassetta, Gilles; Fort, Monique; Bouccara, Fanny; Sourdot, Grégoire; Tassel, Adrien; Lissak, Candide; Betard, François; Cossart, Etienne; Madelin, Malika; Viel, Vincent; Charnay, Bérengère; Bletterie, Xavier

2014-05-01

The upper Guil catchment (Southern Alps) is prone to hydro-geomorphic hazards. Major hazards are related to catastrophic floods, with an amplification of their impacts due to strong hillslope-channel connectivity as observed in 1957 and 2000. In both cases, the rainfall intensity, aggravated by the pre-existing saturated soils, explained the instantaneous response of the fluvial system, such as destabilisation of slopes, high sediment discharge, and subsequent damages to exposed structures and settlements present in the floodplain and at confluence sites. The Peynin junction with the Guil River is one of these sites, where significant land-use change during the last decades in relation to the development of handicraft and tourism economy has increased debris flow threat to population. Here, we adopt a sediment budget analysis aimed at better understanding the functioning of this small subcatchment. This latter offers a combination of factors that favour torrential and gravitational activity. It receives abundant and intense rainfall during "Lombarde" events (moist air mass from Mediterranean Sea). Its elongated shape and small surface area (15 km²) together with asymmetric slopes (counter dip slope on the left bank) accelerate runoff on a short response time. In addition highly tectonised shaly schists supply a large volume of debris (mostly platy clasts and fine, micaceous sediment). The objectives of this study, carried out in the frame of SAMCO (ANR) project, are threefold: Identify the different sediment storages; Characterise the processes that put sediment into motion; Quantify volumes of sediment storages. We produced a geomorphic map using topographic surveys and aerial photos in order to locate the different sediment storage types and associated processes. This analysis was made with respect to geomorphic coupling and sediment flux activity. In terms of surface area, the dominant landforms in the valley were found to be mass wasting, talus slopes and alluvial fans and plains. Most of these forms are relict landforms, decoupled from the present geomorphic system. Notable sediment transport is limited to avalanche tracks, debris flows, and along floodplains. Sediment volumes were calculated using a combination of polynomial functions of cross sections and GIS modelling. We calculated the overall sediment volume of the valley fill deposits to be 1.05 km3. This corresponds to a mean sediment thickness of 90.2 m. Landslides appear as the major sediment storage, representing more than 35% of the sediment volume stored in the Peynin subcatchment. For some locations, the polynomial-generated cross sections resulted in overestimations of sediment thickness, therefore, these results have to be considered as an order of magnitude. Future investigations will include seismic refraction profiles that may provide bedrock depth, hence a better control on sediment thickness (estimates generated thanks to GIS). Eventually, we expect our results to be used to better model, hence prevent future debris-flow events at the confluence of Peynin stream with the Guil River.

Geomorphology, acoustic backscatter, and processes in Santa Monica Bay from multibeam mapping.

PubMed

Gardner, James V; Dartnell, Peter; Mayer, Larry A; Hughes Clarke, John E

2003-01-01

Santa Monica Bay was mapped in 1996 using a high-resolution multibeam system, providing the first substantial update of the submarine geomorphology since the initial compilation by Shepard and Emery [(1941) Geol. Soc. Amer. Spec. Paper 31]. The multibeam mapping generated not only high-resolution bathymetry, but also coregistered, calibrated acoustic backscatter at 95 kHz. The geomorphology has been subdivided into six provinces; shelf, marginal plateau, submarine canyon, basin slope, apron, and basin. The dimensions, gradients, and backscatter characteristics of each province is described and related to a combination of tectonics, climate, sea level, and sediment supply. Fluctuations of eustatic sea level have had a profound effect on the area; by periodically eroding the surface of Santa Monica plateau, extending the mouth of the Los Angeles River to various locations along the shelf break, and by connecting submarine canyons to rivers. A wetter glacial climate undoubtedly generated more sediment to the rivers that then transported the increased sediment load to the low-stand coastline and canyon heads. The trends of Santa Monica Canyon and several bathymetric highs suggest a complex tectonic stress field that has controlled the various segments. There is no geomorphic evidence to suggest Redondo Canyon is fault controlled. The San Pedro fault can be extended more than 30 km to the northwest by the alignment of a series of bathymetric highs and abrupt changes in direction of channel thalwegs.

UAS Photogrammetry for Rapid Response Characterization of Subaerial Coastal Change

NASA Astrophysics Data System (ADS)

Do, C.; Anarde, K.; Figlus, J.; Prouse, W.; Bedient, P. B.

2016-12-01

Unmanned aerial systems (UASs) provide an exciting new platform for rapid response measurement of subaerial coastal change. Here we validate the use of a coupled hobbyist UAS and optical photogrammetry framework for high-resolution mapping of portions of a low-lying barrier island along the Texas Gulf Coast. A DJI Phantom 3 Professional was used to capture 2D nadir images of the foreshore and back-beach environments containing both vegetated and non-vegetated features. The images were georeferenced using ground-truth markers surveyed via real-time kinematic (RTK) GPS and were then imported into Agisoft Photoscan, a photo-processing software, to generate 3D point clouds and digital elevation maps (DEMs). The georeferenced elevation models were then compared to RTK measurements to evaluate accuracy and precision. Thus far, DEMs derived from UAS photogrammetry show centimeter resolution for renderings of non-vegetated landforms. High-resolution renderings of vegetated and back-barrier regions have proven more difficult due to interstitial wetlands (surface reflectance) and uneven terrain for GPS backpack surveys. In addition to producing high-quality models, UAS photogrammetry has demonstrated to be more time-efficient than traditional mapping methods, making it advantageous for rapid response deployments. This study is part of a larger effort to relate field measurements of storm hydrodynamics to subaerial evidence of geomorphic change to better understand barrier island response to extreme storms.

Basis and methods of NASA airborne topographic mapper lidar surveys for coastal studies

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Sallenger, Asbury H.; Krabill, William B.; Swift, Robert N.

2002-01-01

This paper provides an overview of the basic principles of airborne laser altimetry for surveys of coastal topography, and describes the methods used in the acquisition and processing of NASA Airborne Topographic Mapper (ATM) surveys that cover much of the conterminous US coastline. This form of remote sensing, also known as "topographic lidar", has undergone extremely rapid development during the last two decades, and has the potential to contribute within a wide range of coastal scientific investigations. Various airborne laser surveying (ALS) applications that are relevant to coastal studies are being pursued by researchers in a range of Earth science disciplines. Examples include the mapping of "bald earth" land surfaces below even moderately dense vegetation in studies of geologic framework and hydrology, and determination of the vegetation canopy structure, a key variable in mapping wildlife habitats. ALS has also proven to be an excellent method for the regional mapping of geomorphic change along barrier island beaches and other sandy coasts due to storms or long-term sedimentary processes. Coastal scientists are adopting ALS as a basic method in the study of an array of additional coastal topics. ALS can provide useful information in the analysis of shoreline change, the prediction and assessment of landslides along seacliffs and headlands, examination of subsidence causing coastal land loss, and in predicting storm surge and tsunami inundation.

Detailed Analysis of the Intra-Ejecta Dark Plains of Caloris Basin, Mercury

NASA Astrophysics Data System (ADS)

Buczkowski, D.; Seelos, K. D.

2010-12-01

The Caloris basin on Mercury is floored by light-toned plains and surrounded by an annulus of dark-toned material interpreted to be ejecta blocks and smooth, dark, ridged plains. Strangely, preliminary crater-counts indicate that these intra-ejecta dark plains are younger than the light-toned plains within the Caloris basin. This would imply a second, younger plains emplacement event, possibly involving lower albedo material volcanics, which resurfaced the original ejecta deposit. On the other hand, the dark plains may be pre-Caloris light plains covered by a thin layer of dark ejecta. Another alternative to the hypothesis of young, dark volcanism is the possibility that previous crater-counts have not thoroughly distinguished between superposed craters (fresh) and partly-buried craters (old) and therefore have not accurately determined the ages of the Caloris units. We here outline the tasks associated with a new mapping project of the Caloris basin, intended to improve our knowledge of the geology and geologic history of the basin, and thus facilitate an understanding of the thermal evolution of this region of Mercury. We will 1) classify craters based on geomorphology and infilling, 2) create a high-resolution map of the intra-ejecta dark plains, 3) perform crater counts of the intra-ejecta dark plains, the ejecta, and the Caloris floor light plains and 4) refine the stratigraphy of Caloris basin units. We will use new high resolution (200-300 m/p) imaging data from the MDIS instrument to create a new geomorphic map of the dark annulus around the Caloris basin. Known Caloris group formations will be mapped where identified and any new units will be defined and mapped as necessary. Specifically, we will delineate hummocks and smooth plains within the Odin formation and map them separately. We will look for unequivocal evidence of volcanic activity within the dark annulus and the Odin Formation, such as vents and flow lobes. The location of any filled craters will be especially noted, to be incorporated into a new crater classification scheme that includes both degradation state and level and type of infilling. We will also distinguish between craters infilled with 1) lava, 2) impact melt and 3) ejecta, based on our interpretation of the MDIS images. We will then determine the crater size-frequency distribution of each geomorphic unit. We will analyze the crater density of the Caloris floor plains unit, the Odin Formation ejecta and the Odin Formation intra-ejecta dark plains. We will do a second count of Caloris floor craters that includes filled craters, to attempt to get a minimum age for the underlying dark basement. Crater counting on any additional geologic units will depend upon results of the geomorphic mapping. Finally, we will refine the stratigraphy of the Caloris basin units. We start in the region where MESSENGER data over-laps Mariner 10 images. By comparing the Caloris group formations mapped in the Tolstoj and Shakespeare quadrangles to the overlapping MDIS images, we determine the distinctive geomorphology of each of these units in the high resolution MESSENGER data. We will then use this as diagnostic criteria as we map the rest of the basin.

The Twenty-Fifth Lunar and Planetary Science Conference. Part 1: A-G

NASA Technical Reports Server (NTRS)

1994-01-01

Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, and planetary mantles.

Geomorphic Mapping Pool 7 - Upper Mississippi River Basin

DTIC Science & Technology

1987-10-05

PSA deposit (greater than 1 meter). Anderson and Overstreet (1986) have shown that historical sedi- ment in the Iowa River at Coralville reservoir...1986 Holocene Landscape Evolution in the Iowa River Valley: Coralville Reservoir, Iowa . Unpublished M.S. Thesis, University of Wisconsin-Madison, WI...District. Donohue & Associates, Inc. Sheboygan, WI. ANDERSON, JEFFREY D. and D.F. OVERSTREET, 1986, The Archaeology of Coralville Lake, Iowa Volume II

Anthropogenic Factors Affecting the Status of Salmon Stocks in Pacific Northwest Watersheds

DTIC Science & Technology

2006-01-01

effects of anthropogenic trends and climate cycles (Anderson 1999), physical and geomorphic processes (Montgomery et al. 1999), mining ( Maret and...from Washington, Oregon, and California. National Marine Fisheries Service. NOAA Technical Memorandum NMFS-NWFSC- 27. Available online at...bearing watersheds. Available online at www.critfc.org/tech/96- 5report.htm. DeLorme Mapping. 1991. Oregon atlas & gazetteer. First Edition

Modelling Soil-Landscapes in Coastal California Hills Using Fine Scale Terrestrial Lidar

NASA Astrophysics Data System (ADS)

Prentice, S.; Bookhagen, B.; Kyriakidis, P. C.; Chadwick, O.

2013-12-01

Digital elevation models (DEMs) are the dominant input to spatially explicit digital soil mapping (DSM) efforts due to their increasing availability and the tight coupling between topography and soil variability. Accurate characterization of this coupling is dependent on DEM spatial resolution and soil sampling density, both of which may limit analyses. For example, DEM resolution may be too coarse to accurately reflect scale-dependent soil properties yet downscaling introduces artifactual uncertainty unrelated to deterministic or stochastic soil processes. We tackle these limitations through a DSM effort that couples moderately high density soil sampling with a very fine scale terrestrial lidar dataset (20 cm) implemented in a semiarid rolling hillslope domain where terrain variables change rapidly but smoothly over short distances. Our guiding hypothesis is that in this diffusion-dominated landscape, soil thickness is readily predicted by continuous terrain attributes coupled with catenary hillslope segmentation. We choose soil thickness as our keystone dependent variable for its geomorphic and hydrologic significance, and its tendency to be a primary input to synthetic ecosystem models. In defining catenary hillslope position we adapt a logical rule-set approach that parses common terrain derivatives of curvature and specific catchment area into discrete landform elements (LE). Variograms and curvature-area plots are used to distill domain-scale terrain thresholds from short range order noise characteristic of very fine-scale spatial data. The revealed spatial thresholds are used to condition LE rule-set inputs, rendering a catenary LE map that leverages the robustness of fine-scale terrain data to create a generalized interpretation of soil geomorphic domains. Preliminary regressions show that continuous terrain variables alone (curvature, specific catchment area) only partially explain soil thickness, and only in a subset of soils. For example, at spatial scales up 20, curvature explains 40% of soil thickness variance among soils <3 m deep, while soils >3 m deep show no clear relation to curvature. To further demonstration our geomorphic segmentation approach, we apply it to DEM domains where diffusion processes are less dominant than in our primary study area. Classified landform map derived from fine scale terrestrial lidar. Color classes depict hydrogeomorphic process domains in zero order watersheds.

Reproducibility of UAV-based earth surface topography based on structure-from-motion algorithms.

NASA Astrophysics Data System (ADS)

Clapuyt, François; Vanacker, Veerle; Van Oost, Kristof

2014-05-01

A representation of the earth surface at very high spatial resolution is crucial to accurately map small geomorphic landforms with high precision. Very high resolution digital surface models (DSM) can then be used to quantify changes in earth surface topography over time, based on differencing of DSMs taken at various moments in time. However, it is compulsory to have both high accuracy for each topographic representation and consistency between measurements over time, as DSM differencing automatically leads to error propagation. This study investigates the reproducibility of reconstructions of earth surface topography based on structure-from-motion (SFM) algorithms. To this end, we equipped an eight-propeller drone with a standard reflex camera. This equipment can easily be deployed in the field, as it is a lightweight, low-cost system in comparison with classic aerial photo surveys and terrestrial or airborne LiDAR scanning. Four sets of aerial photographs were created for one test field. The sets of airphotos differ in focal length, and viewing angles, i.e. nadir view and ground-level view. In addition, the importance of the accuracy of ground control points for the construction of a georeferenced point cloud was assessed using two different GPS devices with horizontal accuracy at resp. the sub-meter and sub-decimeter level. Airphoto datasets were processed with SFM algorithm and the resulting point clouds were georeferenced. Then, the surface representations were compared with each other to assess the reproducibility of the earth surface topography. Finally, consistency between independent datasets is discussed.

THE HYDROLOGIC SYSTEM: GEOMORPHIC AND HYDROGEOLOGIC CONTROLS ON SURFACE AND SUBSURFACE FLOW REGIMES IN RIPARIAN MEADOW ECOSYSTEMS IN THE CENTRAL GREAT BASIN

EPA Science Inventory

Riparian corridors in upland watersheds in the Great Basin of central Nevada contain the majority of the region's biodiversity. Water, in both surface and subsurface flow regimes, is an important resource sustaining these sensitive ecosystems and other similar riparian ecosystem...

Large landslides associated with a diapiric fold in Canelles Reservoir (Spanish Pyrenees): Detailed geological-geomorphological mapping, trenching and electrical resistivity imaging

NASA Astrophysics Data System (ADS)

Gutiérrez, Francisco; Linares, Rogelio; Roqué, Carles; Zarroca, Mario; Carbonel, Domingo; Rosell, Joan; Gutiérrez, Mateo

2015-07-01

Detailed geomorphological-geological mapping in Canelles Reservoir, the Spanish Pyrenees, reveals the presence of several large landslides overlooked in previous cartographic works. One of the slope movements, designated as the Canelles landslide, corresponds to a 40 × 106 m3 translational landslide reactivated in 2006 by a severe decline in the reservoir water level. The geomorphic features mapped in the upper part of the Canelles landslide, including surface ruptures corroborated by electrical resistivity imaging and trenching, indicate multiple displacement episodes previous to the 2006 human-induced event. Consistently, the stratigraphic and structural relationships observed in a trench record at least two displacement events older and larger in magnitude than the 2006 reactivation. The oldest recorded event occurred in the 6th to 7th Centuries and the second in 1262-1679 yr AD. This latter episode might be correlative to the 1373 Ribagorza earthquake (Mw 6.2), which caused the reactivation of a landslide and the consequent destruction of a village in the adjacent valley. The available data indicate that over more than one millennium the kinematics of the landslide has been characterised by discrete small-displacement episodes. These data, together with the available literature on rapid rockslides, do not concur with the acceleration predicted by modelling in a previous investigation, which foresees a speed of 16 m s- 1 despite the low average dip of the sliding surface (9-10°). This case study illustrates that the trenching technique may provide valuable practical information on the past behaviour of landslides, covering a much broader time span than instrumental and historical records.

The geomorphology of the Chandeleur Island Wetlands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debusschere, K.; Penland, S.; Westphal, K.

1990-09-01

The Chandeleur Islands represent the largest and oldest transgressive barrier island arc in the northern Gulf of Mexico. Generated by the transgressive submergence of the St. Bernard delta complex, the Chandeleur Islands form the protective geologic framework for one of the richest areas of salt marsh and seagrass flats in Louisiana. The Chandeleur barrier island arc is 60 km long and consists of five individual islands backed by a linear, multiple bar system enclosing a shallow basin floored by extensive seagrass flats. The northern part of the Chandeleur chain is the highest in relief, elevation, width, and habitat diversity. Nonstormmore » morphology is predominantly a combination of continuous dunes and dune terraces. Numerous washover channels and large washover fans extend into the backbarrier environment. Further south, the island width decreases and washover flats and terraces dominate the shoreline morphology In the southernmost section, the island arc is fragmented into a series of small islands and shoals separated by tidal inlets. Between 1984 and 1989, aerial videotape, aerial photographic, and bathymetric surveys were used to map and monitor the geomorphic changes occurring along the shoreline and in backbarrier areas. The aerial videotape mapping surveys focused on the impacts of hurricanes Danny, Elena, and Juan on the geomorphology of the islands. Videotape imagery was acquired in July 1984 and in July (prestorm), August (post-Danny), September (post-Elena), and November (post-Juan) 1985. A coastal geomorphic classification was developed to map the spatial and temporal landscape changes between surveys.« less

Multibeam mapping of the Pinnacles region, Gulf of Mexico

USGS Publications Warehouse

Gardner, James V.; Dartnell, Peter; Sulak, Kenneth J.

2002-01-01

Recent USGS mapping shows an extensive deep (~100 m) reef tract occurs on the Mississippi-Alabama outer continental shelf (Figure 1). The tract, known as "The Pinnacles", is apparently part of a sequence of drowned reef complexes along the "40-fathom" shelf edge of the northern Gulf of Mexico (Ludwick and Walton, 1957). It is critical to determine the accurate geomorphology of these deep-reefs because of their importance as benthic habitats for fisheries. The Pinnacles have previously been mapped using a single-beam echo sounder (Ludwick and Walton,1957), sidescan sonar (Laswell et al., 1990), and the TAMU2 towed single-beam sidescan-sonar system (Anonymous, 1999). These existing studies do not provide the quality of geomorphic data necessary for reasonable habitat studies.

The efficacy of stream power and flow duration on geomorphic responses to catastrophic flooding

NASA Astrophysics Data System (ADS)

Magilligan, F. J.; Buraas, E. M.; Renshaw, C. E.

2015-01-01

Geomorphologists have long studied the impacts of extreme floods, yet the association between the magnitude of flow parameters (discharge, velocity, shear stress, or stream power) and resulting geomorphic effectiveness remains vague and non-deterministic. Attempts have been made to include flow duration and total expenditure of stream power, in combination with peak unit stream power, as important variables, but there has been minimal exploration of this hydraulic combination. Taking advantage of Tropical Storm Irene's rapid track through eastern Vermont (USA) in late summer 2011, this paper presents the array of geomorphic responses to a short duration (time to peak of < 8 h) but high magnitude flood that was the twentieth century flood of record for numerous watersheds. We present herein the geomorphic imprint of Tropical Storm Irene flooding within a larger context of fluvial theory concerning the role of, and trade-off between, the magnitude of energy expenditure during a flood and its duration. Focusing on a detailed field effort within the 187-km2 Saxtons River basin in southeastern VT, augmented by select sites along the adjacent lower gradient Williams River (291-km2), we elucidate (1) the geomorphic effects of a short duration flood in a humid, well-vegetated landscape; (2) the relationship between geomorphic response and (a) peak stream power, (b) total stream power, and (c) flow duration of stream power above a critical threshold; and (3) the spatial variation of geomorphic effects relative to reach-scale geologic and geomorphic controls. Flooding associated with Tropical Storm Irene ranged from the 1000 year recurrence interval (RI) flood (based on Weibull flood frequency analysis) to the 300 year RI flood (log Pearson Type III). Discharges spawned a peak unit stream power of 712 W/m2 (Saxtons River) and 361 W/m2 (Williams River), with total energy expenditure throughout the event of ~ 16,000 × 103 and 15,000 × 103 J, respectively. For the Saxtons River, channel widening was spatially infrequent and limited in magnitude; however, other geomorphic effects were profound (1) the entrainment, transport, and deposition of extremely coarse material; (2) stripping of floodplain surfaces; (3) channel avulsions and incision into Pleistocene-aged material; and (4) deposition of coarse material across floodplains. Based on our extensive field data and hydrologic/hydraulic analyses, we contend that short duration, high energy flows can have profound sedimentological effects but have limited erosive, channel widening impacts. Gravel entrainment and deposition of a catastrophic nature can certainly occur under these flow regimes, but the impacts of these extreme flows on channel geometry may have limited expression.

Quaternary landscape development, alluvial fan chronology and erosion of the Mecca Hills at the southern end of the San Andreas Fault zone

USGS Publications Warehouse

Gray, Harrison J.; Owen, Lewis A.; Dietsch, Craig; Beck, Richard A.; Caffee, Marc A.; Finkelman, Robert B.; Mahan, Shannon

2014-01-01

Quantitative geomorphic analysis combined with cosmogenic nuclide 10Be-based geochronology and denudation rates have been used to further the understanding of the Quaternary landscape development of the Mecca Hills, a zone of transpressional uplift along the southern end of the San Andreas Fault, in southern California. The similar timing of convergent uplifts along the San Andreas Fault with the initiation of the sub-parallel San Jacinto Fault suggest a possible link between the two tectonic events. The ages of alluvial fans and the rates of catchment-wide denudation have been integrated to assess the relative influence of climate and tectonic uplift on the development of catchments within the Mecca Hills. Ages for major geomorphic surfaces based on 10Be surface exposure dating of boulders and 10Be depth profiles define the timing of surface stabilization to 2.6 +5.6/–1.3 ka (Qyf1 surface), 67.2 ± 5.3 ka (Qvof2 surface), and 280 ± 24 ka (Qvof1 surface). Comparison of 10Be measurements from active channel deposits (Qac) and fluvial terraces (Qt) illustrate a complex history of erosion, sediment storage, and sediment transport in this environment. Beryllium-10 catchment-wide denudation rates range from 19.9 ± 3.2 to 149 ± 22.5 m/Ma and demonstrate strong correlations with mean catchment slope and with total active fault length normalized by catchment area. The lack of strong correlation with other geomorphic variables suggests that tectonic uplift and rock weakening have the greatest control. The currently measured topography and denudation rates across the Mecca Hills may be most consistent with a model of radial topographic growth in contrast to a model based on the rapid uplift and advection of crust.

Late Quaternary landscape evolution, climate, and neotectonism along the eastern margin of the Puna Plateau: Pucará Valley, NW Argentina

NASA Astrophysics Data System (ADS)

McCarthy, J. A.; Schoenbohm, L. M.; Bierman, P. R.; Rood, D. H.

2013-12-01

The eastern margin of the Puna Plateau has been the focus of many studies seeking to link climatically-moderated surface processes and tectonism through dynamic feedbacks. However, evaluating any theories regarding climatic-tectonic feedbacks requires the determination of tectonic, climatic, and geomorphic chronologies across a wide region, from plateau to wedge-top to foreland. In this study, we contribute to that effort by examining Quaternary landscape evolution of a single intermontane basin of spatially uniform climate, adjacent to the plateau margin. The semi-arid Pucará Valley contains eight abandoned and incised geomorphic surfaces, most of which are deformed by active structures. These geomorphic surfaces - thin alluvial fans and strath terraces - dominate the landscape and record multiple pulses of incision in the late Quaternary. We find no evidence for significant depositional intervals and valley incision continues currently. Substantial accumulations of pedogenic carbonate and pedogenic gypsum within abandoned surfaces indicate that arid or semi-arid conditions are long lived in this valley. Conversely, relict periglacial morphology in adjacent ranges supports cooler temperatures in the past. River incision is enhanced across active structures, but preliminary observations suggest that the magnitude of deformation cannot fully explain the magnitude of incision. As a result, we argue that extrabasinal base-level lowering is the primary driver of incision in the Pucará Valley, but Quaternary deformation is significant enough to spatially influence erosion. Cooler climatic intervals may influence the sedimentology of alluvial and fluvial deposits, but we find no evidence for significant climatic changes that could change rates or styles of landscape evolution over this time frame. Pending cosmogenic nuclide analysis of fan deposits and river sediments will permit the derivation of fault slip rates, surface ages, modern and paleo-erosion rates, and sediment transport histories. These results will further refine our understanding of tectonic and climatic forcing of surface processes in the Quaternary.

Vegetative and geologic mapping of the western Seward Peninsula, Alaska, based on ERTS-1 imagery

NASA Technical Reports Server (NTRS)

Anderson, J. H.; Shapiro, L. H.; Belon, A. E.

1973-01-01

ERTS-1 scene 1009-22095 (Western Seward Peninsula, Alaska) has been studied, partly as a training exercise, to evaluate whether direct visual examination of individual and custom color-composite prints can provide new information on the vegetation and geology of this relatively well known area of Alaska. The vegetation analysis reveals seven major vegetation types, only four of which are described on existing vegetation maps. In addition, the ERTS analysis provides greater detail than the existing maps on the areal distribution of vegetation types. The geologic analysis demonstrates that most of the major rock units and geomorphic boundaries shown on the available geologic maps could also be identified on the ERTS data. Several major high-angle faults were observed, but the zones of thrust faults which are much less obvious.

Chronology of wrinkle ridge formation and rate of crustal shortening on Lunae Planum, Mars

NASA Astrophysics Data System (ADS)

Karagoz, Oguzcan; Aksoy, M. Ersen; Erkeling, Gino

2017-04-01

The Lunae Planum, a plain between the Tharsis Montes and the Acidalia Planitia on Mars, represents a transitional zone from a volcanic rise to a lowland plain, respectively. From West to East at N20°, topography changes from 600 m to -750 m. Here, several wrinkle ridges that are compressional tectonic features formed by folding and thrust faulting [1], mark the surficial deformation of the martian crust. From the analysis of >25 wrinkle ridges in earlier studies a total shortening of ˜1840 m and a compressive strain of 0.29% has been suggested for the Lunae Planum [2]. In this study, we investigate the chronological order of geomorphic structures and determine the timing and duration of the crustal shortening of Lunae Planum. We use remote sensing mapping techniques [3] and crater size-frequency distribution measurements (CSFD) [e.g.,4,5]. In our analyses, we use HRSC (12.5 m/pixel), CTX (6 m/pixel) and HiRISE (0.3 m/pixel) satellite images and digital terrain models to document geomorphic structures such as wrinkles ridges, impact craters, crater ejecta blankets and intermontane plains. Our CSFD measurements of wrinkle ridges reveal an age distribution from 3.9 Ga to 3.0 Ga, with surfaces getting younger towards the East. Our findings are in accordance with earlier observations of greater shortening amounts towards the West (in older ridges) [2]. The age distribution of wrinkle ridges suggests a 9 Ma time interval for the proposed 1840 m horizontal shortening at a deformation rate of 2.04 x 10-3 mm/yr for compressional deformation on the Lunae Planum. [1] Watters, T.R., 2004, Elastic dislocation modeling of wrinkle ridges on Mars, Icarus, 171, 284-294. [2] Plescia, J.B., 1991.Wrinkle ridges in Lunae Planum, Mars: implications for shortening and strain. Geophys. Res. Lett. 18, 913-916. [3] Greeley, R. and Guest, J.E., 1987. Geologic map of the eastern equatorial region of Mars. USGS Miscellaneous Investigations Series Map. [4] Hartmann, W. K., and Neukum, G., 2001, Cratering chronology and the evolution of Mars. Space Sci. Rev. 96, 165-194. [5] Ivanov, B., 2001, Mars / Moon cratering ration estimates. Space Sci. Rev. 96, 87-104.

Influences of Altered River Geomorphology on Channel-Floodplain Mass and Momentum Transfer

NASA Astrophysics Data System (ADS)

Byrne, C. F.; Stone, M. C.

2017-12-01

River management strategies, including both river engineering and restoration, have altered river geomorphology and associated lateral channel-floodplain connectivity throughout the world. This altered connectivity is known to drive changes in ecologic and geomorphic processes during floods, however, quantification of altered connectivity is difficult due to the highly dynamic spatial and temporal nature of flood wave conditions. The objective of this research was to quantify the physical processes of lateral mass and momentum transfer at the channel-floodplain interface. The objective was achieved with the implementation of novel scripting and high-resolution, two-dimensional hydrodynamic modeling techniques under unsteady flow conditions. The process-based analysis focused on three geomorphic feature types within the Middle Rio Grande, New Mexico, USA: (1) historical floodplain surfaces, (2) inset floodplain surfaces formed as a result of channel training and hydrologic alteration, and (3) mechanically restored floodplain surfaces. Results suggest that inset floodplain feature types are not only subject to greater mass and momentum transfer magnitudes, but those connections are also more heterogeneous in nature compared with historical feature types. While restored floodplain feature types exhibit transfer magnitudes and heterogeneity comparable to inset feature types, the surfaces are not of great enough spatial extent to substantially influence total channel-floodplain mass and momentum transfer. Mass and momentum transfer also displayed differing characteristic changes as a result of increased flood magnitude, indicating that linked hydrodynamic processes can be altered differently as a result of geomorphic and hydrologic change. The results display the potential of high-resolution modeling strategies in capturing the spatial and temporal complexities of river processes. In addition, the results have implications for other fields of river science including biogeochemical exchange at the channel-floodplain interface and quantification of process associated with environmental flow and river restoration strategies.

Development of a channel classification to evaluate potential for cottonwood restoration, lower segments of the Middle Missouri River, South Dakota and Nebraska

USGS Publications Warehouse

Jacobson, Robert B.; Elliott, Caroline M.; Huhmann, Brittany L.

2010-01-01

This report documents development of a spatially explicit river and flood-plain classification to evaluate potential for cottonwood restoration along the Sharpe and Fort Randall segments of the Middle Missouri River. This project involved evaluating existing topographic, water-surface elevation, and soils data to determine if they were sufficient to create a classification similar to the Land Capability Potential Index (LCPI) developed by Jacobson and others (U.S. Geological Survey Scientific Investigations Report 2007–5256) and developing a geomorphically based classification to apply to evaluating restoration potential.Existing topographic, water-surface elevation, and soils data for the Middle Missouri River were not sufficient to replicate the LCPI. The 1/3-arc-second National Elevation Dataset delineated most of the topographic complexity and produced cumulative frequency distributions similar to a high-resolution 5-meter topographic dataset developed for the Lower Missouri River. However, lack of bathymetry in the National Elevation Dataset produces a potentially critical bias in evaluation of frequently flooded surfaces close to the river. High-resolution soils data alone were insufficient to replace the information content of the LCPI. In test reaches in the Lower Missouri River, soil drainage classes from the Soil Survey Geographic Database database correctly classified 0.8–98.9 percent of the flood-plain area at or below the 5-year return interval flood stage depending on state of channel incision; on average for river miles 423–811, soil drainage class correctly classified only 30.2 percent of the flood-plain area at or below the 5-year return interval flood stage. Lack of congruence between soil characteristics and present-day hydrology results from relatively rapid incision and aggradation of segments of the Missouri River resulting from impoundments and engineering. The most sparsely available data in the Middle Missouri River were water-surface elevations. Whereas hydraulically modeled water-surface elevations were available at 1.6-kilometer intervals in the Lower Missouri River, water-surface elevations in the Middle Missouri River had to be interpolated between streamflow-gaging stations spaced 3–116 kilometers. Lack of high-resolution water-surface elevation data precludes development of LCPI-like classification maps.An hierarchical river classification framework is proposed to provide structure for a multiscale river classification. The segment-scale classification presented in this report is deductive and based on presumed effects of dams, significant tributaries, and geological (and engineered) channel constraints. An inductive reach-scale classification, nested within the segment scale, is based on multivariate statistical clustering of geomorphic data collected at 500-meter intervals along the river. Cluster-based classifications delineate reaches of the river with similar channel and flood-plain geomorphology, and presumably, similar geomorphic and hydrologic processes. The dominant variables in the clustering process were channel width (Fort Randall) and valley width (Sharpe), followed by braiding index (both segments).Clusters with multithread and highly sinuous channels are likely to be associated with dynamic channel migration and deposition of fresh, bare sediment conducive to natural cottonwood germination. However, restoration potential within these reaches is likely to be mitigated by interaction of cottonwood life stages with the highly altered flow regime.

Spatial and temporal sensitivity of hydrogeomorphic responceand recovery to deforestation, Agriculture, and floods

USGS Publications Warehouse

Fitzpatrick, F.A.; Knox, J.C.

2000-01-01

Clear-cut logging followed by agricultural activity caused hydrologic and geomorphic changes in North Fish Creek, a Wisconsin tributary to Lake Superior. Hydro-geomorphic responses to changes in land use were sensitive to the location of reaches along the main stem and to the relative timing of large floods. Hydrologic and sediment-load modeling indicates that flood peaks were three times larger and sediment loads were five times larger during maximum agricultural activity in the 1920s and 1930s than prior to about 1890, when forest cover was dominant. Following logging, overbank sedimentation rates in the lower main stem increased four to six times above pre-settlement rates. Accelerated streambank and channel erosion in the upper main stem have been and continue to be primary sources of sediment to downstream reaches. Extreme floods in 1941 and 1946, followed by frequent moderate floods through 1954, caused extensive geomorphic changes along the entire main stem. Sedimentation rates in the lower main stem may have decreased in the last several decades as agricultural activity declined. However, geomorphic recovery is slow, as incised channels in the upper main stem function as efficient conveyors of watershed surface runoff and thereby continue to promote flooding and sedimentation problems downstream. [Key words: fluvial geomorphology, floods, erosion, sedimentation, deforestation, agriculture.].

Geomorphological aspects of road construction in a cold environment, Finland

NASA Astrophysics Data System (ADS)

Seppälä, Matti

1999-12-01

Traditionally, road alignments followed easy landscapes and suitable landforms. When traffic and the size and weight of vehicles increased and higher speeds were used, straighter roads were required; the easygoing relief could not always be used, and problems arose. Road contractors could save money in building and maintenance costs by considering the geomorphic facts. The examples from Finland document why road construction is very expensive in the conditions generated by severe winters. In Finland, more paved roads cross the Arctic Circle than in the whole of North America. This paper gives examples of geomorphic elements affecting road construction in a cold environment: eskers, drumlins, plains of late and postglacial glaciolacustrine and marine sediments, mires, steep rock cliffs, river channels and ice-dams, fluvial erosion, and palsas. Solutions to these problems include removal of frost sensible materials and replacement by more favorable sediments. Road surfaces, kept snow-free in the wintertime, are subjected to deep freezing. The maintenance of roads can be supported with some solutions that affect snowdrift and icing problems, avoidance of geomorphic factors that cause problems, and by using natural processes to help people. Some examples of how road construction affects geomorphic processes and vice versa are provided. For example, bridges block moving river ice, and on special occasions, road banks cause icing.

TerraceM: A Matlab® tool to analyze marine terraces from high-resolution topography

NASA Astrophysics Data System (ADS)

Jara-Muñoz, Julius; Melnick, Daniel; Strecker, Manfred

2015-04-01

To date, Light detection and ranging (LiDAR), high- resolution topographic data sets enable remote identification of submeter-scale geomorphic features bringing valuable information of the landscape and geomorphic markers of tectonic deformation such as fault-scarp offsets, fluvial and marine terraces. Recent studies of marine terraces using LiDAR data have demonstrated that these landforms can be readily isolated from other landforms in the landscape, using slope and roughness parameters that allow for unambiguously mapping regional extents of terrace sequences. Marine terrace elevation has been used since decades as geodetic benchmarks of Quaternary deformation. Uplift rates may be estimated by locating the shoreline angle, a geomorphic feature correlated with the high-stand position of past sea levels. Indeed, precise identification of the shoreline-angle position is an important requirement to obtain reliable tectonic rates and coherent spatial correlation. To improve our ability to rapidly assess and map different shoreline angles at a regional scale we have developed the TerraceM application. TerraceM is a Matlab® tool that allows estimating the shoreline angle and its associated error using high-resolution topography. For convenience, TerraceM includes a graphical user interface (GUI) linked with Google Maps® API. The analysis starts by defining swath profiles from a shapefile created on a GIS platform orientated orthogonally to the terrace riser. TerraceM functions are included to extract and analyze the swath profiles. Two types of coastal landscapes may be analyzed using different methodologies: staircase sequences of multiple terraces and rough, rocky coasts. The former are measured by outlining the paleo-cliffs and paleo-platforms, whereas the latter are assessed by picking the elevation of sea-stack tops. By calculating the intersection between first-order interpolations of the maximum topography of swath profiles we define the shoreline angle in staircase terraces. For rocky coasts, the maximum stack peaks for a defined search ratio as well as a defined inflection point on the adjacent main cliff are interpolated to calculate the shoreline angle at the intersection with the cliff. Error estimates are based on the standard deviation of the linear regressions. The geomorphic age of terraces (Kt) can be also calculated by the linear diffusion equation (Hanks et al., 1989), with a best-fitting model found by minimizing the RMS. TerraceM has the ability to efficiently process several profiles in batch-mode run. Results may be exported in various formats, including Google Earth and ArcGis, basic statistics are automatically computed. Test runs have been made at Santa Cruz, California, using various topographic data sets and comparing results with published field measurements (Anderson and Menking, 1994). Repeatability was evaluated using multiple test runs made by students in a classroom setting.

Geomorphology, active tectonics, and landscape evolution in the Mid-Atlantic region: Chapter

USGS Publications Warehouse

Pazzaglia, Frank J.; Carter, Mark W.; Berti, Claudio; Counts, Ronald C.; Hancock, Gregory S.; Harbor, David; Harrison, Richard W.; Heller, Matthew J.; Mahan, Shannon; Malenda, Helen; McKeon, Ryan; Nelson, Michelle S.; Prince, Phillip; Rittenour, Tammy M.; Spotilla, James; Whittecar, G. Richard

2015-01-01

In 2014, the geomorphology community marked the 125th birthday of one of its most influential papers, “The Rivers and Valleys of Pennsylvania” by William Morris Davis. Inspired by Davis’s work, the Appalachian landscape rapidly became fertile ground for the development and testing of several grand landscape evolution paradigms, culminating with John Hack’s dynamic equilibrium in 1960. As part of the 2015 GSA Annual Meeting, the Geomorphology, Active Tectonics, and Landscape Evolution field trip offers an excellent venue for exploring Appalachian geomorphology through the lens of the Appalachian landscape, leveraging exciting research by a new generation of process-oriented geomorphologists and geologic field mapping. Important geomorphologic scholarship has recently used the Appalachian landscape as the testing ground for ideas on long- and short-term erosion, dynamic topography, glacial-isostatic adjustments, active tectonics in an intraplate setting, river incision, periglacial processes, and soil-saprolite formation. This field trip explores a geologic and geomorphic transect of the mid-Atlantic margin, starting in the Blue Ridge of Virginia and proceeding to the east across the Piedmont to the Coastal Plain. The emphasis here will not only be on the geomorphology, but also the underlying geology that establishes the template and foundation upon which surface processes have etched out the familiar Appalachian landscape. The first day focuses on new and published work that highlights Cenozoic sedimentary deposits, soils, paleosols, and geomorphic markers (terraces and knickpoints) that are being used to reconstruct a late Cenozoic history of erosion, deposition, climate change, and active tectonics. The second day is similarly devoted to new and published work documenting the fluvial geomorphic response to active tectonics in the Central Virginia seismic zone (CVSZ), site of the 2011 M 5.8 Mineral earthquake and the integrated record of Appalachian erosion preserved on the Coastal Plain. The trip concludes on Day 3, joining the Kirk Bryan Field Trip at Great Falls, Virginia/ Maryland, to explore and discuss the dramatic processes of base-level fall, fluvial incision, and knickpoint retreat.

Late Quaternary geomorphic history of a glacial landscape - new sedimentary and chronological data from the Cordillera de Cochabamba (Bolivia)

NASA Astrophysics Data System (ADS)

May, J.-H.; Preusser, F.; Zech, R.; Ilgner, J.; Veit, H.

2009-04-01

Throughout the Central Andes, glacial landscapes have long been used for the reconstruction of Late Quaternary glaciations and landscape evolution. Much work has focused on the Andes in Peru, Chile and the Bolivian Altiplano, whereas relatively little data has been published on glaciation history in the eastern Andean ranges and slopes. Even less is known with regard to the postglacial evolution of these glacial landscapes. In the Cordillera de Cochabamba (Bolivia), local maximum advances probably peaked around 20-25 ka BP and were followed by significant readvances between ~12-16 ka BP. This generally points to temperature controlled maximum glacial advances along the humid eastern slopes of the Central Andes, which is supported by glacier-climate-modelling studies. However, most studies include only marginal information with regard to the complex geomorphic and sedimentary situation in the Cordillera de Cochabamba. Furthermore, the chronological results are afflicted with several methodological uncertainties inherent to surface exposure dating and call for application of alternative, independent age dating methods. Therefore this study aims at i) documenting and interpreting the complex glacial geomorphology of the Huara Loma valley in the Cordillera de Cochabamba (Bolivia), ii) analyzing the involved units of glacial sediments, and iii) improving the chronological framework by applying optically stimulated luminescence (OSL) and radiocarbon dating (14C). For this purpose, geomorphic mapping was combined with field documentation of sedimentary profiles. The involved sediments were subject to geochemical and mineralogical analysis in order to deduce information on their erosional and weathering histories. In addition, the interpretation of OSL ages from glacial and proglacial sediments integrated several methodological procedures with regard to sample preparation and statistical analysis of the measurements in order to increase the degree of confidence. These combined efforts confirm two major glacial advances in the Cordillera de Cochabamba, which took place during the global LGM and during the Lateglacial. However, their relative chronologies and sedimentary interpretation indicate that the maximum extent of glaciation at Huara Loma was reached during humid Lateglacial times whereas conditions during the LGM were probably too dry.

The long-term legacy of geomorphic and riparian vegetation feedbacks on the dammed Bill Williams River, Arizona, USA

USGS Publications Warehouse

Kui, Li; Stella, John C.; Shafroth, Patrick B.; House, P. Kyle; Wilcox, Andrew C.

2017-01-01

On alluvial rivers, fluvial landforms and riparian vegetation communities codevelop as a result of feedbacks between plants and abiotic processes. The influence of vegetation on river channel and floodplain geomorphology can be particularly strong on dammed rivers with altered hydrology and reduced flood disturbance. We used a 56-year series of aerial photos on the dammed Bill Williams River (Arizona, USA) to investigate how (a) different woody riparian vegetation types influence river channel planform and (b) how different fluvial landforms drive the composition of riparian plant communities over time. We mapped vegetation types and geomorphic surfaces and quantified how relations between fluvial and biotic processes covaried over time using linear mixed models. In the decades after the dam was built, woody plant cover within the river's bottomland nearly doubled, narrowing the active channel by 60% and transforming its planform from wide and braided to a single thread and more sinuous channel. Compared with native cottonwood–willow vegetation, nonnative tamarisk locally induced a twofold greater reduction in channel braiding. Vegetation expanded at different rates depending on the type of landform, with tamarisk cover on former high-flow channels increasing 17% faster than cottonwood–willow. Former low-flow channels with frequent inundation supported a greater increase in cottonwood–willow relative to tamarisk. These findings give insight into how feedbacks between abiotic and biotic processes in river channels accelerate and fortify changes triggered by dam construction, creating river systems increasingly distinct from predam ecological communities and landforms, and progressively more resistant to restoration of predam forms and processes.

Spatial heterogeneity of within-stream methane concentrations

USGS Publications Warehouse

Crawford, John T.; Loken, Luke C.; West, William E.; Crary, Benjamin; Spawn, Seth A.; Gubbins, Nicholas; Jones, Stuart E.; Striegl, Robert G.; Stanley, Emily H.

2017-01-01

Streams, rivers, and other freshwater features may be significant sources of CH4 to the atmosphere. However, high spatial and temporal variabilities hinder our ability to understand the underlying processes of CH4 production and delivery to streams and also challenge the use of scaling approaches across large areas. We studied a stream having high geomorphic variability to assess the underlying scale of CH4 spatial variability and to examine whether the physical structure of a stream can explain the variation in surface CH4. A combination of high-resolution CH4 mapping, a survey of groundwater CH4 concentrations, quantitative analysis of methanogen DNA, and sediment CH4 production potentials illustrates the spatial and geomorphic controls on CH4 emissions to the atmosphere. We observed significant spatial clustering with high CH4 concentrations in organic-rich stream reaches and lake transitions. These sites were also enriched in the methane-producing mcrA gene and had highest CH4 production rates in the laboratory. In contrast, mineral-rich reaches had significantly lower concentrations and had lesser abundances of mcrA. Strong relationships between CH4and the physical structure of this aquatic system, along with high spatial variability, suggest that future investigations will benefit from viewing streams as landscapes, as opposed to ecosystems simply embedded in larger terrestrial mosaics. In light of such high spatial variability, we recommend that future workers evaluate stream networks first by using similar spatial tools in order to build effective sampling programs.

Drainage basin and topographic analysis of a tropical landscape: Insights into surface and tectonic processes in northern Borneo

NASA Astrophysics Data System (ADS)

Mathew, Manoj Joseph; Menier, David; Siddiqui, Numair; Ramkumar, Mu.; Santosh, M.; Kumar, Shashi; Hassaan, Muhammad

2016-07-01

We investigated the recent landscape development of Borneo through geomorphic analysis of two large drainage basins (Rajang and Baram basins). The extraction of morphometric parameters utilizing digital terrain data in a GIS environment, focusing on hydrography (stream length-gradient index, ratio of valley floor width to valley height, and transverse topographic symmetry factor) and topography (local relief and relief anomaly), was carried out in order to elucidate processes governing drainage and landscape evolution. Anomalously high and low values of stream length-gradient indices of main tributary streams associated with faults and multiple knick-points along the channel profiles are linked to deformation events. The development of deeply incised V-shaped valleys show enhanced incision capability of streams in response to steepening of hillslope gradients following tectonic inputs. Deflection of streams and probable dynamic reorganization of the drainage system through stream capture processes as feedbacks to tectonic uplift and orographic effect are observed. Local relief and relief anomaly maps highlight the presence of preserved elevation-accordant relict portions of landscapes characterized by low amplitude relief, nested between ridgelines in regions of complex folding. Our results reveal dynamic geomorphic adjustment of the landscape due to perturbations in tectonic and climatic boundary conditions. The implication is that the landscape of north Borneo experienced a tectonic phase of rapid uplift after 5 Ma and undergoes active folding of the Rajang Group thrust belts in the present-day. Active shortening combined with high rates of denudation in Sarawak, demonstrates transience emphasized by the drainage system attempting to adjust to tectonic and climatic forcing.

River Sensitivity and Catchment Connectivity: Key Controls on Geomorphic Response and Effectiveness

NASA Astrophysics Data System (ADS)

Lisenby, P.; Fryirs, K.; Croke, J.

2016-12-01

The sensitivity of river channels to adjustment and the dynamics of sediment connectivity along a channel network are key controls on the capacity (ability) for a river system to adjust, i.e. the severity, distribution, and type of geomorphic response to disturbance events. In turn, the cumulative impact of geomorphic responses compared with event magnitude will determine the geomorphic effectiveness of a single disturbance event. River sensitivity and sediment connectivity can change significantly over space and time, and vary with changes in internal factors such as channel type and geomorphic landform and external factors such as event sequencing and lithological controls. Correspondingly, the capacity for a geomorphic system to respond to disturbance events will also vary, so that geomorphic effectiveness is not definitively characterized by a static relationship between event magnitude and geomorphic response, but rather is a dynamic comparison between geomorphic response and an actively changing capacity for geomorphic adjustment. Herein, we use the Lockyer Valley, Queensland as a case study to illustrate the variability of river sensitivity and sediment connectivity. We relate this variability to the potential and capacity for geomorphic channel response. We find that the sensitivity to and capacity for geomorphic adjustment varies significantly with channel morphometry and valley position. Additionally, the nature of bedload sediment connectivity changes with the distribution of geomorphic landforms and channel weirs that can impede sediment transference through the system. This variability of river sensitivity and sediment connectivity will control the nature of geomorphic response to disturbance events within the Lockyer Valley. Ultimately, determinations of geomorphic effectiveness for disturbance events will depend on comparisons of their geomorphic impacts with the capacity of the Lockyer geomorphic system to respond.

Valley plugs, land use, and phytogeomorphic response: Chapter 14

USGS Publications Warehouse

Pierce, Aaron R.; King, Sammy L.; Shroder, John F.

2013-01-01

Anthropogenic alteration of fluvial systems can disrupt functional processes that provide valuable ecosystem services. Channelization alters fluvial parameters and the connectivity of river channels to their floodplains which is critical for productivity, nutrient cycling, flood control, and biodiversity. The effects of channelization can be exacerbated by local geology and land-use activities, resulting in dramatic geomorphic readjustments including the formation of valley plugs. Considerable variation in the response of abiotic processes, including surface hydrology, subsurface hydrology, and sedimentation dynamics, to channelization and the formation of valley plugs. Altered abiotic processes associated with these geomorphic features and readjustments influence biotic processes including species composition, abundance, and successional processes. Considerable interest exists for restoring altered fluvial systems and their floodplains because of their social and ecological importance. Understanding abiotic and biotic responses of channelization and valley-plug formation within the context of the watershed is essential to successful restoration. This chapter focuses on the primary causes of valley-plug formation, resulting fluvial-geomorphic responses, vegetation responses, and restoration and research needs for these systems.

The Arctic in the Twenty-First Century: Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland.

PubMed

Anderson, N John; Saros, Jasmine E; Bullard, Joanna E; Cahoon, Sean M P; McGowan, Suzanne; Bagshaw, Elizabeth A; Barry, Christopher D; Bindler, Richard; Burpee, Benjamin T; Carrivick, Jonathan L; Fowler, Rachel A; Fox, Anthony D; Fritz, Sherilyn C; Giles, Madeleine E; Hamerlik, Ladislav; Ingeman-Nielsen, Thomas; Law, Antonia C; Mernild, Sebastian H; Northington, Robert M; Osburn, Christopher L; Pla-Rabès, Sergi; Post, Eric; Telling, Jon; Stroud, David A; Whiteford, Erika J; Yallop, Marian L; Yde, Jacob C

2017-02-01

The Kangerlussuaq area of southwest Greenland encompasses diverse ecological, geomorphic, and climate gradients that function over a range of spatial and temporal scales. Ecosystems range from the microbial communities on the ice sheet and moisture-stressed terrestrial vegetation (and their associated herbivores) to freshwater and oligosaline lakes. These ecosystems are linked by a dynamic glacio-fluvial-aeolian geomorphic system that transports water, geological material, organic carbon and nutrients from the glacier surface to adjacent terrestrial and aquatic systems. This paraglacial system is now subject to substantial change because of rapid regional warming since 2000. Here, we describe changes in the eco- and geomorphic systems at a range of timescales and explore rapid future change in the links that integrate these systems. We highlight the importance of cross-system subsidies at the landscape scale and, importantly, how these might change in the near future as the Arctic is expected to continue to warm.

The Arctic in the Twenty-First Century: Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland

PubMed Central

Anderson, N. John; Saros, Jasmine E.; Bullard, Joanna E.; Cahoon, Sean M. P.; McGowan, Suzanne; Bagshaw, Elizabeth A.; Barry, Christopher D.; Bindler, Richard; Burpee, Benjamin T.; Carrivick, Jonathan L.; Fowler, Rachel A.; Fox, Anthony D.; Fritz, Sherilyn C.; Giles, Madeleine E.; Hamerlik, Ladislav; Ingeman-Nielsen, Thomas; Law, Antonia C.; Mernild, Sebastian H.; Northington, Robert M.; Osburn, Christopher L.; Pla-Rabès, Sergi; Post, Eric; Telling, Jon; Stroud, David A.; Whiteford, Erika J.; Yallop, Marian L.; Yde, Jacob C.

2017-01-01

Abstract The Kangerlussuaq area of southwest Greenland encompasses diverse ecological, geomorphic, and climate gradients that function over a range of spatial and temporal scales. Ecosystems range from the microbial communities on the ice sheet and moisture-stressed terrestrial vegetation (and their associated herbivores) to freshwater and oligosaline lakes. These ecosystems are linked by a dynamic glacio-fluvial-aeolian geomorphic system that transports water, geological material, organic carbon and nutrients from the glacier surface to adjacent terrestrial and aquatic systems. This paraglacial system is now subject to substantial change because of rapid regional warming since 2000. Here, we describe changes in the eco- and geomorphic systems at a range of timescales and explore rapid future change in the links that integrate these systems. We highlight the importance of cross-system subsidies at the landscape scale and, importantly, how these might change in the near future as the Arctic is expected to continue to warm. PMID:28596614

USE OF CONTINUOUS DATALOGGERS TO ASSESS THE TEMPORAL AND SPATIAL VARIATION OF GROUND WATER/SURFACE WATER INTERACTION BEFORE AND AFTER STREAM RESTORATION

EPA Science Inventory

Minebank Run is a degraded second-order flashy urban stream in Baltimore County which is slated to undergo restoration in August 2003 to re-establish geomorphic stability. We are currently conducting an intensive investigation of surface water/ground water interaction and nutrien...

Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z

NASA Technical Reports Server (NTRS)

1993-01-01

Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, K-T Boundary Layer, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, planetary mantles, and space exploration.

Tectonic Geomorphology.

ERIC Educational Resources Information Center

Bull, William B.

1984-01-01

Summarizes representative quantitative tectonic-geomorphology studies made during the last century, focusing on fault-bounded mountain-front escarpments, marine terraces, and alluvial geomorphic surfaces (considering stream terraces, piedmont fault scarps, and soils chronosequences). Also suggests where tectonic-geomorphology courses may best fit…

Integration of spectral, spatial and morphometric data into lithological mapping: A comparison of different Machine Learning Algorithms in the Kurdistan Region, NE Iraq

NASA Astrophysics Data System (ADS)

Othman, Arsalan A.; Gloaguen, Richard

2017-09-01

Lithological mapping in mountainous regions is often impeded by limited accessibility due to relief. This study aims to evaluate (1) the performance of different supervised classification approaches using remote sensing data and (2) the use of additional information such as geomorphology. We exemplify the methodology in the Bardi-Zard area in NE Iraq, a part of the Zagros Fold - Thrust Belt, known for its chromite deposits. We highlighted the improvement of remote sensing geological classification by integrating geomorphic features and spatial information in the classification scheme. We performed a Maximum Likelihood (ML) classification method besides two Machine Learning Algorithms (MLA): Support Vector Machine (SVM) and Random Forest (RF) to allow the joint use of geomorphic features, Band Ratio (BR), Principal Component Analysis (PCA), spatial information (spatial coordinates) and multispectral data of the Advanced Space-borne Thermal Emission and Reflection radiometer (ASTER) satellite. The RF algorithm showed reliable results and discriminated serpentinite, talus and terrace deposits, red argillites with conglomerates and limestone, limy conglomerates and limestone conglomerates, tuffites interbedded with basic lavas, limestone and Metamorphosed limestone and reddish green shales. The best overall accuracy (∼80%) was achieved by Random Forest (RF) algorithms in the majority of the sixteen tested combination datasets.

Geologic map of MTM -15027, -20027, -25027, and -25032 quadrangles, Margaritifer Terra region of Mars

USGS Publications Warehouse

Irwin, Rossman P.; Grant, John A.

2013-01-01

Mars Transverse Mercator (MTM) quadrangles −15027, −20027, −25027, and −25032 (lat 12.5°−28° S., long 330°−335° E. and lat 22.5°−28° S., long 324.5°−330° E.) in southwestern Margaritifer Terra include diverse erosional landforms, sedimentary deposits, and tectonic structures that record a long geologic and geomorphic history. The northeastern regional slope of the pre-Noachian crustal dichotomy (as expressed along the Chryse trough) and structures of the informally named Middle Noachian or older Holden and Ladon impact basins dominate the topography of the map area. A series of mesoscale outflow channels, Uzboi, Ladon, and Morava Valles, integrated these formerly enclosed basins by overflow and incision around the Noachian/Hesperian transition, although some flooding may have occurred earlier. The area includes excellent examples of Late Noachian to Hesperian valley networks, dissected crater rims, alluvial fans, deltas, and light-toned layered deposits, particularly in Holden and Eberswalde craters. Structural forms include Tharsis-radial grabens, Hesperian wrinkle ridges, floor-fractured impact craters, and severely disrupted chaotic terrains. These well-preserved landforms and sedimentary deposits represent multiple erosional epochs and discrete flooding events, which provide significant insight into the geomorphic processes and climate change on early Mars.

Establishing A Geologic Baseline of Cape Canaveral''s Natural Landscape: Black Point Drive

NASA Technical Reports Server (NTRS)

Parkinson, Randall W.

2002-01-01

The goal of this project is to identify the process responsible for the formation of geomorphic features in the Black Point Drive area of Merritt Island National Wildlife Refuge/Kennedy Space Center (MINWR/KSC), northwest Cape Canaveral. This study confirms the principal landscape components (geomorphology) of Black Point Drive reflect interaction between surficial sediments deposited in association with late-Quaternary sea-level highstands and the chemical evolution of late-Cenozoic sub-surface limestone formations. The Black Point Drive landscape consists of an undulatory mesic terrain which dips westward into myriad circular and channel-like depression marshes and lakes. This geomorphic gradient may reflect: (1) spatial distinctions in the elevation, character or age of buried (pre-Miocene) limestone formations, (2) dissolution history of late-Quaternary coquina and/or (3) thickness of unconsolidated surface sediment. More detailed evaluation of subsurface data will be necessary before this uncertain0 can be resolved.

Fault Scarp Detection Beneath Dense Vegetation Cover: Airborne Lidar Mapping of the Seattle Fault Zone, Bainbridge Island, Washington State

NASA Technical Reports Server (NTRS)

Harding, David J.; Berghoff, Gregory S.

2000-01-01

The emergence of a commercial airborne laser mapping industry is paying major dividends in an assessment of earthquake hazards in the Puget Lowland of Washington State. Geophysical observations and historical seismicity indicate the presence of active upper-crustal faults in the Puget Lowland, placing the major population centers of Seattle and Tacoma at significant risk. However, until recently the surface trace of these faults had never been identified, neither on the ground nor from remote sensing, due to cover by the dense vegetation of the Pacific Northwest temperate rainforests and extremely thick Pleistocene glacial deposits. A pilot lidar mapping project of Bainbridge Island in the Puget Sound, contracted by the Kitsap Public Utility District (KPUD) and conducted by Airborne Laser Mapping in late 1996, spectacularly revealed geomorphic features associated with fault strands within the Seattle fault zone. The features include a previously unrecognized fault scarp, an uplifted marine wave-cut platform, and tilted sedimentary strata. The United States Geologic Survey (USGS) is now conducting trenching studies across the fault scarp to establish ages, displacements, and recurrence intervals of recent earthquakes on this active fault. The success of this pilot study has inspired the formation of a consortium of federal and local organizations to extend this work to a 2350 square kilometer (580,000 acre) region of the Puget Lowland, covering nearly the entire extent (approx. 85 km) of the Seattle fault. The consortium includes NASA, the USGS, and four local groups consisting of KPUD, Kitsap County, the City of Seattle, and the Puget Sound Regional Council (PSRC). The consortium has selected Terrapoint, a commercial lidar mapping vendor, to acquire the data.

Morphologic Evolution of the Mount St. Helens Crater Area, Washington

NASA Technical Reports Server (NTRS)

Beach, G. L.

1985-01-01

The large rockslide-avalanche that preceded the eruption of Mount St. Helens on 18 May 1980 removed approximately 2.8 cubic km of material from the summit and north flank of the volcano, forming a horseshoe-shaped crater 2.0 km wide and 3.9 km long. A variety of erosional and depositional processes, notably mass wasting and gully development, acted to modify the topographic configuration of the crater area. To document this morphologic evolution, a series of annual large-scale topographic maps is being produced as a base for comparitive geomorphic analysis. Four topographic maps of the Mount St. Helens crater area at a scale of 1:4000 were produced by the National Mapping Division of the U. S. Geological Survey. Stereo aerial photography for the maps was obtained on 23 October 1980, 10 September 1981, 1 September 1982, and 17 August 1983. To quantify topographic changes in the study area, each topographic map is being digitized and corresponding X, Y, and Z values from successive maps are being computer-compared.

Long-term channel adjustment and geomorphic feature creation by vegetation in a lowland, low energy river

NASA Astrophysics Data System (ADS)

Grabowski, Robert; Gurnell, Angela

2016-04-01

Physical habitat restoration is increasingly being used to improve the ecological status of rivers. This is particularly true for lowland streams which are perceived to lack sufficient energy to create new features or to flush out fine sediment derived from agricultural and urban sources. However, this study has found that even in low-energy, base-flow dominated chalk streams, physical habitat improvement can happen naturally without direct human intervention. Furthermore this positive change is achieved by components of the river that are often regarded as management problems: in-stream macrophytes (i.e. weed), riparian trees, woody debris, and most importantly fine sediment. This project investigated the long-term changes in channel planform for the River Frome (Dorset, UK) over the last 120 years and the role of aquatic and riparian vegetation in driving this change. Agricultural census data, historical maps, recent aerial images and field observations were analysed within a process-based, hierarchical framework for hydromorphological assessment, developed in the EU FP7 REFORM project, to investigate the source and timing of fine sediment production in the catchment, to quantify the reach-scale geomorphic response, and to identify vegetation-related bedforms that could be responsible for the adjustment. The analysis reveals that the channel has narrowed and become more sinuous in the last 50-60 years. The timing of this planform adjustment correlates with substantial changes in land use and agricultural practices (post-World War II) that are known to increase soil erosion and sediment connectivity. The field observations and recent aerial images suggest that the increased delivery of fine sediment to the channel has been translated into geomorphic adjustment and diversification though the interactions between vegetation, water flow and sediment. Emergent aquatic macrophytes are retaining fine sediment, leading to the development of submerged shelves that aggrade over time to form bars, berms and benches. This process drives the extension of the river bank into the channel, narrowing it and increasing sinuosity. In reaches with well-developed woody riparian vegetation, the geomorphic changes are more complex, with fine sediment being absorbed into a diverse mosaic of geomorphic features initiated by living trees and large wood. This study underlines the importance of vegetation for the geomorphic adjustment and diversification of lowland rivers and as a component of sustainable river management.

Methods of Determining Playa Surface Conditions Using Remote Sensing

DTIC Science & Technology

1987-10-08

NO. 11. TITLE (include Security Classification) METHODS OF DETERMINING PLAYA SURFACE CONDITIONS USING REMOTE SENSING 12. PERSONAL AUTHOR(S) J. PONDER...PLAYA SURFACE CONDITIONS USING REMOTE SENSING J. Ponder Henley U. S. Army Engineer Topographic Laboratories Fort Belvoir, Virginia 22060-5546 "ABSTRACT...geochemistry, hydrology and remote sensing but all of these are important to the understanding of these unique geomorphic features. There is a large body

Systematic Mapping and Statistical Analyses of Valley Landform and Vegetation Asymmetries Across Hydroclimatic Gradients

NASA Astrophysics Data System (ADS)

Poulos, M. J.; Pierce, J. L.; McNamara, J. P.; Flores, A. N.; Benner, S. G.

2015-12-01

Terrain aspect alters the spatial distribution of insolation across topography, driving eco-pedo-hydro-geomorphic feedbacks that can alter landform evolution and result in valley asymmetries for a suite of land surface characteristics (e.g. slope length and steepness, vegetation, soil properties, and drainage development). Asymmetric valleys serve as natural laboratories for studying how landscapes respond to climate perturbation. In the semi-arid montane granodioritic terrain of the Idaho batholith, Northern Rocky Mountains, USA, prior works indicate that reduced insolation on northern (pole-facing) aspects prolongs snow pack persistence, and is associated with thicker, finer-grained soils, that retain more water, prolong the growing season, support coniferous forest rather than sagebrush steppe ecosystems, stabilize slopes at steeper angles, and produce sparser drainage networks. We hypothesize that the primary drivers of valley asymmetry development are changes in the pedon-scale water-balance that coalesce to alter catchment-scale runoff and drainage development, and ultimately cause the divide between north and south-facing land surfaces to migrate northward. We explore this conceptual framework by coupling land surface analyses with statistical modeling to assess relationships and the relative importance of land surface characteristics. Throughout the Idaho batholith, we systematically mapped and tabulated various statistical measures of landforms, land cover, and hydroclimate within discrete valley segments (n=~10,000). We developed a random forest based statistical model to predict valley slope asymmetry based upon numerous measures (n>300) of landscape asymmetries. Preliminary results suggest that drainages are tightly coupled with hillslopes throughout the region, with drainage-network slope being one of the strongest predictors of land-surface-averaged slope asymmetry. When slope-related statistics are excluded, due to possible autocorrelation, valley slope asymmetry is most strongly predicted by asymmetries of insolation and drainage density, which generally supports a water-balance based conceptual model of valley asymmetry development. Surprisingly, vegetation asymmetries had relatively low predictive importance.

Development of remote sensing technology in New Zealand, part 1. Mapping land use and environmental studies in New Zealand, part 2. Indigenous forest assessment, part 3. Seismotectonic, structural, volcanologic and geomorphic study of New Zealand, part 4

NASA Technical Reports Server (NTRS)

Probine, M. C.; Suggate, R. P.; Stirling, I. F.; Mcgreevy, M. G. (Principal Investigator)

1976-01-01

The author has identified the following significant results. As part of the tape reformatting process, a simple coded picture output program was developed. This represents Pixel's radiance level by one of a 47 character set on a nonoverprinting line printer. It not only has aided in locating areas for the reformatting process, but has also formed the foundation for a supervised clustering package. This in turn has led to a simplistic but effective thematic mapping package.

Ecologically relevant geomorphic attributes of streams are impaired by even low levels of watershed effective imperviousness

NASA Astrophysics Data System (ADS)

Vietz, Geoff J.; Sammonds, Michael J.; Walsh, Christopher J.; Fletcher, Tim D.; Rutherfurd, Ian D.; Stewardson, Michael J.

2014-02-01

Urbanization almost inevitably results in changes to stream morphology. Understanding the mechanisms for such impacts is a prerequisite to minimizing stream degradation and achieving restoration goals. However, investigations of urban-induced changes to stream morphology typically use indicators of watershed urbanization that may not adequately represent degrading mechanisms and commonly focus on geomorphic attributes such as channel dimensions that may be of little significance to the ecological goals for restoration. We address these shortcomings by testing if a measure characterizing urban stormwater drainage system connections to streams (effective imperviousness, EI) is a better predictor of change to ecologically relevant geomorphic attributes than a more general measure of urban density (total imperviousness, TI). We test this for 17 sites in independent watersheds across a gradient of urbanization. We found that EI was a better predictor of all geomorphic variables tested than was TI. Bank instability was positively correlated with EI, while width/depth (a measure of channel incision), bedload sediment depth, and frequency of bars, benches, and large wood were negatively correlated. Large changes in all geomorphic variables were detected at very low levels of EI (< 2-3%). Excess urban stormwater runoff, as represented by EI, drives geomorphic change in urban streams, highlighting the dominant role of the stormwater drainage system in efficiently transferring stormwater runoff from impervious surfaces to the stream, as found for ecological indicators. It is likely that geomorphic condition of streams in urbanizing watersheds, particularly those attributes of ecological relevance, can only be maintained if excess urban stormwater flows are kept out of streams through retention and harvesting. The extent to which EI can be reduced within urban and urbanizing watersheds, through techniques such as distributed stormwater harvesting and infiltration, and the components of the hydrologic regime to be addressed, requires further investigation. Urbanization influences stream morphology more than any other land use (Douglas, 2011): it alters hydrology and sediment inputs leading to deepening and widening of streams (Chin, 2006). Concomitantly, urbanization often directly impairs stream morphology through channel and riparian zone interventions, e.g., culverts (Hawley et al., 2012), rock protection (Vietz et al., 2012b), and constricted floodplains (Gurnell et al., 2007). These changes to channel geomorphology in turn contribute to poor in-stream ecological condition (Morley and Karr, 2002; Walsh et al., 2005b; Gurnell et al., 2007; Elosegi et al., 2010).The common conception is that channels undergo gross morphologic alterations if > 10-20% of their watershed is covered by impervious surfaces (total imperviousness, TI; Bledsoe and Watson, 2001; Chin, 2006; Table 1). Many of these studies may, however, underestimate the influence of urbanization by using insensitive channel metrics and assessing streams in early stages of urbanization. Most importantly, TI, as a measure of urban density, may not adequately represent the way in which urbanization alters the master variables of flow and sediment within a watershed.Hydrologists have long recognized that, rather than the proportion of impervious cover within a watershed, it is the proportion that is directly connected to the stream through stormwater drainage systems that may be a better predictor of urban-induced hydrologic change (Leopold, 1968). Referred to as effective imperviousness (EI) the proportion of impervious cover directly connected to the stream through stormwater drainage systems may also be a better predictor of geomorphic response than is TI. Over the last decade a direct measure of EI has been found to be a better predictor of ecological response in urban streams (Walsh et al., 2012), but use of such a metric has not found its way into geomorphic studies even though TI has been found to be ineffective (e.g., Bledsoe et al., 2012). A direct measure of EI - one that specifically accounts for the drainage from each impervious surface rather than using a generic reduction factor (e.g., Booth and Jackson, 1997; Wang et al., 2001) - has not previously been used in geomorphic investigations. In this paper, we advance on past studies by testing if EI is a stronger predictor than TI for urban-induced channel change.A second limitation of previous studies of urban-induced morphologic change is the common focus on channel dimensions (Chin, 2006). These are important for infrastructure and flood protection but do not necessarily have a strong mechanistic link to stream ecosystems. While some notable exceptions exist (Finkenbine et al., 2000; McBride and Booth, 2005), other geomorphic attributes are rarely investigated.This study examines how urbanization of a watershed can result in the impairment of a suite of geomorphic attributes of relevance to aquatic ecosystem condition, such as large wood, sediment availability, and structural and hydraulic complexity (of the bed, bank, and water column), represented by the following variables:

Benthic Assemblages of the Anton Dohrn Seamount (NE Atlantic): Defining Deep-Sea Biotopes to Support Habitat Mapping and Management Efforts with a Focus on Vulnerable Marine Ecosystems.

PubMed

Davies, Jaime S; Stewart, Heather A; Narayanaswamy, Bhavani E; Jacobs, Colin; Spicer, John; Golding, Neil; Howell, Kerry L

2015-01-01

In 2009 the NW and SE flanks of Anton Dohrn Seamount were surveyed using multibeam echosounder and video ground-truthing to characterise megabenthic biological assemblages (biotopes) and assess those which clearly adhere to the definition of Vulnerable Marine Ecosystems, for use in habitat mapping. A combination of multivariate analysis of still imagery and video ground-truthing defined 13 comprehensive descriptions of biotopes that function as mapping units in an applied context. The data reveals that the NW and SE sides of Anton Dohrn Seamount (ADS) are topographically complex and harbour diverse biological assemblages, some of which agree with current definitions of 'listed' habitats of conservation concern. Ten of these biotopes could easily be considered Vulnerable Marine Ecosystems; three coral gardens, four cold-water coral reefs, two xenophyophore communities and one sponge dominated community, with remaining biotopes requiring more detailed assessment. Coral gardens were only found on positive geomorphic features, namely parasitic cones and radial ridges, found both sides of the seamount over a depth of 1311-1740 m. Two cold-water coral reefs (equivalent to summit reef) were mapped on the NW side of the seamount; Lophelia pertusa reef associated with the cliff top mounds at a depth of 747-791 m and Solenosmilia variabilis reef on a radial ridge at a depth of 1318-1351 m. Xenophyophore communities were mapped from both sides of the seamount at a depth of 1099-1770 m and were either associated with geomorphic features or were in close proximity (< 100 m) to them. The sponge dominated community was found on the steep escarpment either side of the seamount over at a depth of 854-1345 m. Multivariate diversity revealed the xenophyophore biotopes to be the least diverse, and a hard substratum biotope characterised by serpulids and the sessile holothurian, Psolus squamatus, as the most diverse.

Benthic Assemblages of the Anton Dohrn Seamount (NE Atlantic): Defining Deep-Sea Biotopes to Support Habitat Mapping and Management Efforts with a Focus on Vulnerable Marine Ecosystems

PubMed Central

Davies, Jaime S.; Stewart, Heather A.; Narayanaswamy, Bhavani E.; Jacobs, Colin; Spicer, John; Golding, Neil; Howell, Kerry L.

2015-01-01

In 2009 the NW and SE flanks of Anton Dohrn Seamount were surveyed using multibeam echosounder and video ground-truthing to characterise megabenthic biological assemblages (biotopes) and assess those which clearly adhere to the definition of Vulnerable Marine Ecosystems, for use in habitat mapping. A combination of multivariate analysis of still imagery and video ground-truthing defined 13 comprehensive descriptions of biotopes that function as mapping units in an applied context. The data reveals that the NW and SE sides of Anton Dohrn Seamount (ADS) are topographically complex and harbour diverse biological assemblages, some of which agree with current definitions of ‘listed’ habitats of conservation concern. Ten of these biotopes could easily be considered Vulnerable Marine Ecosystems; three coral gardens, four cold-water coral reefs, two xenophyophore communities and one sponge dominated community, with remaining biotopes requiring more detailed assessment. Coral gardens were only found on positive geomorphic features, namely parasitic cones and radial ridges, found both sides of the seamount over a depth of 1311–1740 m. Two cold-water coral reefs (equivalent to summit reef) were mapped on the NW side of the seamount; Lophelia pertusa reef associated with the cliff top mounds at a depth of 747–791 m and Solenosmilia variabilis reef on a radial ridge at a depth of 1318-1351 m. Xenophyophore communities were mapped from both sides of the seamount at a depth of 1099–1770 m and were either associated with geomorphic features or were in close proximity (< 100 m) to them. The sponge dominated community was found on the steep escarpment either side of the seamount over at a depth of 854-1345 m. Multivariate diversity revealed the xenophyophore biotopes to be the least diverse, and a hard substratum biotope characterised by serpulids and the sessile holothurian, Psolus squamatus, as the most diverse. PMID:25992572

Bathymetry of Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie Reservoirs, New York, 2013–15

USGS Publications Warehouse

Nystrom, Elizabeth A.

2018-02-01

Drinking water for New York City is supplied from several large reservoirs, including a system of reservoirs west of the Hudson River. To provide updated reservoir capacity tables and bathymetry maps of the City’s six West of Hudson reservoirs, bathymetric surveys were conducted by the U.S. Geological Survey from 2013 to 2015. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system along planned transects at predetermined intervals for each reservoir. A separate quality assurance dataset of echo sounder points was collected along transects at oblique angles to the main transects for accuracy assessment. Field-survey data were combined with water surface elevations in a geographic information system to create three-dimensional surfaces in the form of triangulated irregular networks (TINs) representing the elevations of the reservoir geomorphology. The TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were then used to create raster surfaces and 2-foot-interval contour maps of the reservoirs. Elevation-area-capacity tables were calculated at 0.01-foot intervals. The results of the surveys show that the total capacity of the West of Hudson reservoirs has decreased by 11.5 billion gallons (Ggal), or 2.3 percent, since construction, and the useable capacity (the volume above the minimum operating level required to deliver full flow for drinking water supply) has decreased by 7.9 Ggal (1.7 percent). The available capacity (the volume between the spillway elevation and the lowest intake or sill elevation used for drinking water supply) decreased by 9.6 Ggal (2.0 percent), and dead storage (the volume below the lowest intake or sill elevation) decreased by 1.9 Ggal (11.6 percent).

The 2016-2017 central Italy coseismic surface ruptures and their meaning with respect to foreseen active fault systems segmentation

NASA Astrophysics Data System (ADS)

De Martini, P. M.; Pucci, S.; Villani, F.; Civico, R.; Del Rio, L.; Cinti, F. R.; Pantosti, D.

2017-12-01

In 2016-2017 a series of moderate to large normal faulting earthquakes struck central Italy producing severe damage in many towns including Amatrice, Norcia and Visso and resulting in 299 casualties and >20,000 homeless. The complex seismic sequence depicts a multiple activation of the Mt. Vettore-Mt. Bove (VBFS) and the Laga Mts. fault systems, which were considered in literature as independent segments characterizing a recent seismic gap in the region comprised between two modern seismic sequences: the 1997-1998 Colfiorito and the 2009 L'Aquila. We mapped in detail the coseismic surface ruptures following three mainshocks (Mw 6.0 on 24th August, Mw 5.9 and Mw 6.5 on 26th and 30th October, 2016, respectively). Primary surface ruptures were observed and recorded for a total length of 5.2 km, ≅10 km and ≅25 km, respectively, along closely-spaced, parallel or subparallel, overlapping or step-like synthetic and antithetic fault splays of the activated fault systems, in some cases rupturing repeatedly the same location. Some coseismic ruptures were mapped also along the Norcia Fault System, paralleling the VBFS about 10 km westward. We recorded geometric and kinematic characteristics of the normal faulting ruptures with an unprecedented detail thanks to almost 11,000 oblique photographs taken from helicopter flights soon after the mainshocks, verified and integrated with field data (more than 7000 measurements). We analyze the along-strike coseismic slip and slip vectors distribution to be observed in the context of the geomorphic expression of the disrupted slopes and their depositional and erosive processes. Moreover, we constructed 1:10.000 scale geologic cross-sections based on updated maps, and we reconstructed the net offset distribution of the activated fault system to be compared with the morphologic throws and to test a cause-effect relationship between faulting and first-order landforms. We provide a reconstruction of the 2016 coseismic rupture pattern as representative of the VBFS behavior, a discussion on the fault system boundaries persistence, and on the significance of the repeated surface faulting at same location.

Geologic map of MTM -40252 and -40257 quadrangles, Reull Vallis region of Mars

USGS Publications Warehouse

Mest, Scott C.; Crown, David A.

2002-01-01

Mars Transverse Mercator (MTM) quadrangles -40252 and -40257 cover a portion of the highlands of Promethei Terra northeast of the Hellas basin. The map area consists of heavily cratered ancient highland materials of moderate to high relief, isolated knobs and massifs of rugged mountainous materials, extensive tracts of smooth and channeled plains, and other surficial deposits. Reull Vallis, an approximately 1,500 km-long outflow channel system, cuts through the southeast corner of the map area. Regional slopes are to the southwest, toward the Hellas basin, as indicated by Martian topographic maps and the orientations of channels along the northeast rim of the Hellas basin. The Martian highlands cover more than 60 percent of the planet's surface and are primarily in the southern hemisphere. Most of the highlands consist of rugged, densely cratered terrains believed to represent the final phase of heavy bombardment in the inner solar system about 4.0 billion years ago. Parts of the Martian highlands show evidence of extensive degradation and modification. The map area shows landforms created by numerous geologic processes, including tectonism, fluvial activity, and mass wasting. The occurrence of fluvial features, such as outflow channels and valley networks, has significant implications for past Martian conditions. Determining the geology of the highlands northeast of the Hellas basin provides a better understanding of the role and timing of volatile-driven activity in the evolution of the highlands. Photogeologic mapping at 1:500,000 scale from analysis of Viking Orbiter images complements geomorphic studies of Reull Vallis and other highland outflow systems, of drainage networks, and of highland debris aprons and regional geologic mapping studies of the highlands at the 1:2,000,000 scale and 1:1,000,000 scale. Crater size-frequency distributions have been compiled to constrain the relative ages of geologic units and determine the timing and extents of the observed geologic processes.

On the non-uniqueness of the hydro-geomorphic responses in a zero-order catchment with respect to soil moisture

NASA Astrophysics Data System (ADS)

Kim, Jongho; Dwelle, M. Chase; Kampf, Stephanie K.; Fatichi, Simone; Ivanov, Valeriy Y.

2016-06-01

This study advances mechanistic interpretation of predictability challenges in hydro-geomorphology related to the role of soil moisture spatial variability. Using model formulations describing the physics of overland flow, variably saturated subsurface flow, and erosion and sediment transport, this study explores (1) why a basin with the same mean soil moisture can exhibit distinctly different spatial moisture distributions, (2) whether these varying distributions lead to non-unique hydro-geomorphic responses, and (3) what controls non-uniqueness in relation to the response type. Two sets of numerical experiments are carried out with two physically-based models, HYDRUS and tRIBS+VEGGIE+FEaST, and their outputs are analyzed with respect to pre-storm moisture state. The results demonstrate that distinct spatial moisture distributions for the same mean wetness arise because near-surface soil moisture dynamics exhibit different degrees of coupling with deeper-soil moisture and the process of subsurface drainage. The consequences of such variations are different depending on the type of hydrological response. Specifically, if the predominant runoff response is of infiltration excess type, the degree of non-uniqueness is related to the spatial distribution of near-surface moisture. If runoff is governed by subsurface stormflow, the extent of deep moisture contributing area and its "readiness to drain" determine the response characteristics. Because the processes of erosion and sediment transport superimpose additional controls over factors governing runoff generation and overland flow, non-uniqueness of the geomorphic response can be highly dampened or enhanced. The explanation is sediment composed by multi-size particles can alternate states of mobilization or surface shielding and the transient behavior is inherently intertwined with the availability of mobile particles. We conclude that complex nonlinear dynamics of hydro-geomorphic processes are inherent expressions of physical interactions. As complete knowledge of watershed properties, states, or forcings will always present the ultimate, if ever resolvable, challenge, deterministic predictability will remain handicapped. Coupling of uncertainty quantification methods and space-time physics-based approaches will need to evolve to facilitate mechanistic interpretations and informed practical applications.

Active tectonic deformation along rejuvenated faults in tropical Borneo: Inferences obtained from tectono-geomorphic evaluation

NASA Astrophysics Data System (ADS)

Mathew, Manoj Joseph; Menier, David; Siddiqui, Numair; Kumar, Shashi Gaurav; Authemayou, Christine

2016-08-01

The island of Borneo is enveloped by tropical rainforests and hostile terrain characterized by high denudation rates. Owing to such conditions, studies pertaining to neotectonics and consequent geomorphic expressions with regard to surface processes and landscape evolution are inadequately constrained. Here we demonstrate the first systematic tectono-geomorphic evaluation of north Borneo through quantitative and qualitative morphotectonic analysis at sub-catchment scale, for two large drainage basins located in Sarawak: the Rajang and Baram basins. The extraction of morphometric parameters utilizing digital elevation models arranged within a GIS environment focuses on hypsometric curve analysis, distribution of hypsometric integrals through spatial autocorrelation statistics, relative uplift values, the asymmetry factor and the normalized channel steepness index. Hypsometric analysis suggests a young topography adjusting to changes in tectonic boundary conditions. Autocorrelation statistics show clusters of high values of hypsometric integrals as prominent hotspots that are associated with less eroded, young topography situated in the fold and thrust belts of the Interior Highlands of Borneo. High channel steepness and gradients (> 200 m0.9) are observed in zones corresponding to the hotspots. Relative uplift values reveal the presence of tectonically uplifted blocks together with relatively subsided or lesser uplifted zones along known faults. Sub-catchments of both basins display asymmetry indicating tectonic tilting. Stream longitudinal profiles demonstrate the presence of anomalies in the form of knickzones without apparent lithological controls along their channel reaches. Surfaces represented by cold spots of low HI values and low channel gradients observed in the high elevation headwaters of both basins are linked to isolated erosional planation surfaces that could be remnants of piracy processes. The implication of our results is that Borneo experiences active folding of the Rajang Group fold-thrust belt to present and these events reactivated old major faults and minor related dislocations. From geomorphic analysis associated with sedimentary record, we posit that the terrain could have undergone high uplift rates since 5 Ma or multi-phased uplift with periodic intermittent pulses of high and low uplift rates.

Time-dependent landslide probability mapping

USGS Publications Warehouse

Campbell, Russell H.; Bernknopf, Richard L.; ,

1993-01-01

Case studies where time of failure is known for rainfall-triggered debris flows can be used to estimate the parameters of a hazard model in which the probability of failure is a function of time. As an example, a time-dependent function for the conditional probability of a soil slip is estimated from independent variables representing hillside morphology, approximations of material properties, and the duration and rate of rainfall. If probabilities are calculated in a GIS (geomorphic information system ) environment, the spatial distribution of the result for any given hour can be displayed on a map. Although the probability levels in this example are uncalibrated, the method offers a potential for evaluating different physical models and different earth-science variables by comparing the map distribution of predicted probabilities with inventory maps for different areas and different storms. If linked with spatial and temporal socio-economic variables, this method could be used for short-term risk assessment.

Debris flow hazard mapping, Hobart, Tasmania, Australia

NASA Astrophysics Data System (ADS)

Mazengarb, Colin; Rigby, Ted; Stevenson, Michael

2015-04-01

Our mapping on the many dolerite capped mountains in Tasmania indicates that debris flows are a significant geomorphic process operating there. Hobart, the largest city in the State, lies at the foot of one of these mountains and our work is focussed on identifying areas that are susceptible to these events and estimating hazard in the valley systems where residential developments have been established. Geomorphic mapping with the benefit of recent LiDAR and GIS enabled stereo-imagery has allowed us to add to and refine a landslide inventory in our study area. In addition, a dominant geomorphic model has been recognised involving headward gully retreat in colluvial materials associated with rainstorms explains why many past events have occurred and where they may occur in future. In this paper we will review the landslide inventory including a large event (~200 000m3) in 1872 that affected a lightly populated area but since heavily urbanised. From this inventory we have attempted volume-mobility relationships, magnitude-frequency curves and likelihood estimates. The estimation of volume has been challenging to determine given that the area of depletion for each debris flow feature is typically difficult to distinguish from the total affected area. However, where LiDAR data exists, this uncertainty is substantially reduced and we develop width-length relationships (area of depletion) and area-volume relationships to estimate volume for the whole dataset exceeding 300 features. The volume-mobility relationship determined is comparable to international studies and in the absence of reliable eye-witness accounts, suggests that most of the features can be explained as single event debris flows, without requiring more complex mechanisms (such as those that form temporary debris dams that subsequently fail) as proposed by others previously. Likelihood estimates have also been challenging to derive given that almost all of the events have not been witnessed, some are constrained by aerial photographs to decade precision and many predate regional photography (pre 1940's). We have performed runout modelling, using 2D hydraulic modelling software (RiverFlow2D with Mud and Debris module), in order to calibrate our model against real events and gain confidence in the choice of parameters. Runout modelling was undertaken in valley systems with volumes calibrated to existing flood model likelihoods for each catchment. The hazard outputs from our models require developing a translation to hazard models used in Australia. By linking to flood mapping we aim to demonstrate to emergency managers where existing mitigation measures may be inadequate and how they can be adapted to address multiple hazards.

A statistical method for estimating rates of soil development and ages of geologic deposits: A design for soil-chronosequence studies

USGS Publications Warehouse

Switzer, P.; Harden, J.W.; Mark, R.K.

1988-01-01

A statistical method for estimating rates of soil development in a given region based on calibration from a series of dated soils is used to estimate ages of soils in the same region that are not dated directly. The method is designed specifically to account for sampling procedures and uncertainties that are inherent in soil studies. Soil variation and measurement error, uncertainties in calibration dates and their relation to the age of the soil, and the limited number of dated soils are all considered. Maximum likelihood (ML) is employed to estimate a parametric linear calibration curve, relating soil development to time or age on suitably transformed scales. Soil variation on a geomorphic surface of a certain age is characterized by replicate sampling of soils on each surface; such variation is assumed to have a Gaussian distribution. The age of a geomorphic surface is described by older and younger bounds. This technique allows age uncertainty to be characterized by either a Gaussian distribution or by a triangular distribution using minimum, best-estimate, and maximum ages. The calibration curve is taken to be linear after suitable (in certain cases logarithmic) transformations, if required, of the soil parameter and age variables. Soil variability, measurement error, and departures from linearity are described in a combined fashion using Gaussian distributions with variances particular to each sampled geomorphic surface and the number of sample replicates. Uncertainty in age of a geomorphic surface used for calibration is described using three parameters by one of two methods. In the first method, upper and lower ages are specified together with a coverage probability; this specification is converted to a Gaussian distribution with the appropriate mean and variance. In the second method, "absolute" older and younger ages are specified together with a most probable age; this specification is converted to an asymmetric triangular distribution with mode at the most probable age. The statistical variability of the ML-estimated calibration curve is assessed by a Monte Carlo method in which simulated data sets repeatedly are drawn from the distributional specification; calibration parameters are reestimated for each such simulation in order to assess their statistical variability. Several examples are used for illustration. The age of undated soils in a related setting may be estimated from the soil data using the fitted calibration curve. A second simulation to assess age estimate variability is described and applied to the examples. ?? 1988 International Association for Mathematical Geology.

Improved Regolith-Landform and Geological Mapping using AIRSAR Data as an Aid to Mineral Exploration in the North-Eastern Goldfields Region, Western Australia

NASA Technical Reports Server (NTRS)

Tapley, Ian J.

1996-01-01

The distinctive contribution of AIRSAR data in characterizing the regolith-landforms in a relatively vegetation free environment are discussed. AIRSAR frame processed data were initially MAF-cleaned to enhance the signal content of the data before geocoding to AMG coordinates. Colors in a three frequency single polarization combination image C-, L- P- bands, and in an enhancement of pedestal height, relate directly to the scale of surface roughness of the various regolith units Examination of the AIRSAR enhancements reveals that in mafic terrain, and to a lesser extent, in felsic terrain, AIRSAR data provides discrimination between the principle geomorphic regimes, relict, erosional and depositional. A multivariate statistical technique called an all-possible subsets calculation was used to examine the degree of polarimetric separation between selected regolith-landforms for all combinations of the nine band AIRSAR radar. An unanticipated aspect of the research was the identification on the AIRSAR imagery of previously unmapped structural features.

Global spatial indexing of the human impact on Al, Cu, Fe, and Zn mobilization.

PubMed

Rauch, Jason N

2010-08-01

With increasing consumption of material by human activity, the extent of human influence relative to nature in the mobilization of metals and other elements on Earth continues to grow. Recognizing people as modern geomorphic agents, I produced global data layers at 1 degreesx1 degrees of human-mediated mass flows (coal combustion, biomass burning, and mining) and nature-mediated mass flows (net primary productivity, sea salt aerosol emission, and denudation to the oceans) for the industrial metals of aluminum, iron, copper, and zinc for the year 2000. The major mobilization processes are denudation (natural) and mining (anthropic), though net primary productivity for Zn and Cu and coal combustion for Al are nearly as significant. All flows are subsequently combined into an index representing human versus nature flow dominance. As the first maps of mobilization flows of metals widely used by modern technology, they reveal that approximately 1-5% (depending upon the metal) of Earth's land surface now has metal flow dominated by human activity.

Topographic expression of active faults in the foothills of the Northern Apennines

NASA Astrophysics Data System (ADS)

Picotti, Vincenzo; Ponza, Alessio; Pazzaglia, Frank J.

2009-09-01

Active faults that rupture the earth's surface leave an imprint on the topography that is recognized using a combination of geomorphic and geologic metrics including triangular facets, the shape of mountain fronts, the drainage network, and incised river valleys with inset terraces. We document the presence of a network of active, high-angle extensional faults, collectively embedded in the actively shortening mountain front of the Northern Apennines, that possess unique geomorphic expressions. We measure the strain rate for these structures and find that they have a constant throw-to-length ratio. We demonstrate the necessary and sufficient conditions for triangular facet development in the footwalls of these faults and argue that rock-type exerts the strongest control. The slip rates of these faults range from 0.1 to 0.3 mm/yr, which is similar to the average rate of river incision and mountain front unroofing determined by corollary studies. The faults are a near-surface manifestation of deeper crustal processes that are actively uplifting rocks and growing topography at a rate commensurate with surface processes that are eroding the mountain front to base level.

An approach for quantifying geomorphological impacts for EIA of transportation infrastructures: a case study in northern Spain

NASA Astrophysics Data System (ADS)

Bonachea, Jaime; Bruschi, Viola Maria; Remondo, Juan; González-Díez, Alberto; Salas, Luis; Bertens, Jurjen; Cendrero, Antonio; Otero, César; Giusti, Cecilia; Fabbri, Andrea; González-Lastra, José Ramón; Aramburu, José María

2005-03-01

A methodological proposal for the assessment of impacts due to linear infrastructures such as motorways, railways, etc. is presented. The approach proposed includes a series of specific issues to be addressed for each geomorphological feature analysed—both 'static' and 'dynamic'—as well as a series of steps to be followed in the process. Geomorphic characteristics potentially affected were initially identified on the basis of a conceptual activities/impacts model that helps to single out geomorphic impacts related to environmental concerns for the area. The following issues were addressed for each individual impact: nature of potential effects; indicators that can be used to measure impacts; criteria of 'geomorphologic performance'; procedure for measurement/prediction of changes; translation of geomorphologic impacts into significant terms from the viewpoint of human concerns; possible mitigation and/or compensation measures. The procedure has been applied to a case study corresponding to a new motorway in the Basque Country, northern Spain. Geomorphological impacts considered in this analysis included: (1) consumable resources; (2) sites of geomorphological interest; (3) land units with high potential for use, high productivity or value for conservation; (4) visual landscape; (5) slope instability processes. The procedure has been designed for implementation in a Geographic Information System (GIS) environment. Details are given on the application of the method to each individual impact analysed and results are presented in both numerical and map form. Impacts assessed were initially expressed by means of heterogeneous magnitudes, depending on the geomorphological feature considered. Those geomorphological impacts were then translated into significant terms and homogeneous magnitudes. Integration was carried out on the basis of impact values thus obtained. Final integrated results were also expressed in numerical and map form. The method proposed enables comparison of alternatives as well as 'prediction' and assessment of impacts in terms directly related to geomorphic characteristics. It also facilitates the expression of those impacts in terms that allow integration with other types of environmental impacts.

Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado

USGS Publications Warehouse

Ruleman, C.A.; Thompson, R.A.; Shroba, R.R.; Anderson, M.; Drenth, B.J.; Rotzien, J.; Lyon, J.

2013-01-01

The Sunshine Valley-Costilla Plain, a structural subbasin of the greater San Luis Basin of the northern Rio Grande rift, is bounded to the north and south by the San Luis Hills and the Red River fault zone, respectively. Surficial mapping, neotectonic investigations, geochronology, and geophysics demonstrate that the structural, volcanic, and geomorphic evolution of the basin involves the intermingling of climatic cycles and spatially and temporally varying tectonic activity of the Rio Grande rift system. Tectonic activity has transferred between range-bounding and intrabasin faults creating relict landforms of higher tectonic-activity rates along the mountain-piedmont junction. Pliocene–Pleistocene average long-term slip rates along the southern Sangre de Cristo fault zone range between 0.1 and 0.2 mm/year with late Pleistocene slip rates approximately half (0.06 mm/year) of the longer Quaternary slip rate. During the late Pleistocene, climatic influences have been dominant over tectonic influences on mountain-front geomorphic processes. Geomorphic evidence suggests that this once-closed subbasin was integrated into the Rio Grande prior to the integration of the once-closed northern San Luis Basin, north of the San Luis Hills, Colorado; however, deep canyon incision, north of the Red River and south of the San Luis Hills, initiated relatively coeval to the integration of the northern San Luis Basin.Long-term projections of slip rates applied to a 1.6 km basin depth defined from geophysical modeling suggests that rifting initiated within this subbasin between 20 and 10 Ma. Geologic mapping and geophysical interpretations reveal a complex network of northwest-, northeast-, and north-south–trending faults. Northwest- and northeast-trending faults show dual polarity and are crosscut by north-south– trending faults. This structural model possibly provides an analog for how some intracontinental rift structures evolve through time.

40 CFR 194.25 - Future state assumptions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... compliance application, to the extent practicable, the effects of potential changes to future climate cycles... any compliance application, to the extent practicable, the effects of potential changes to... changes to geologic conditions, including, but not limited to: Dissolution; near surface geomorphic...

40 CFR 194.25 - Future state assumptions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... compliance application, to the extent practicable, the effects of potential changes to future climate cycles... any compliance application, to the extent practicable, the effects of potential changes to... changes to geologic conditions, including, but not limited to: Dissolution; near surface geomorphic...

40 CFR 194.25 - Future state assumptions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... compliance application, to the extent practicable, the effects of potential changes to future climate cycles... any compliance application, to the extent practicable, the effects of potential changes to... changes to geologic conditions, including, but not limited to: Dissolution; near surface geomorphic...

40 CFR 194.25 - Future state assumptions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... compliance application, to the extent practicable, the effects of potential changes to future climate cycles... any compliance application, to the extent practicable, the effects of potential changes to... changes to geologic conditions, including, but not limited to: Dissolution; near surface geomorphic...

40 CFR 194.25 - Future state assumptions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... compliance application, to the extent practicable, the effects of potential changes to future climate cycles... any compliance application, to the extent practicable, the effects of potential changes to... changes to geologic conditions, including, but not limited to: Dissolution; near surface geomorphic...

Geologic Map of MTM -40277, -45277, -40272, and -45272 Quadrangles, Eastern Hellas Planitia Region of Mars

USGS Publications Warehouse

Bleamaster, Leslie F.; Crown, David A.

2010-01-01

Hellas Planitia comprises the floor deposits of the Hellas basin, more than 2,000 km across and 8 km deep, which is located in the southern hemisphere's cratered highlands and is the largest well-preserved impact structure on the Martian surface. The circum-Hellas highlands represent a significant percentage of the southern hemisphere of Mars and have served as a locus for volcanic and sedimentary activity throughout Martian geologic time. Hellas basin topography has had a long-lasting influence, acting as Mars' deepest and second largest depositional sink, as a source for global dust storms, and as a forcing agent on southern hemisphere atmospheric circulation. The region lies in the Martian mid-latitude zone where geomorphic indicators of past, and possibly contemporary, ground ice are prominent. The highlands north of the basin show concentrations of Noachian valley networks, and those to the east show prominent lobate debris aprons that are considered to be geomorphic indicators of ground ice. Several studies have proposed that Hellas itself was the site of extensive glacial and lacustrine activity. Recent analyses of mineralogical information from Mars Express' OMEGA (Observatoire pour la Mineralogie, l'Eau les Glaces et l'Activite) and Mars Reconnaissance Orbiter's CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) reveal outcrops of hydrated phyllosilicates in the region, strengthening an already strong case for past aqueous activity in and around Hellas basin. Our mapping and evaluation of landforms and materials of the Hellas region from basin rim to floor provides further insight into Martian global climate regimes and into the abundance, distribution, and flux of volatiles through history. Mars Transverse Mercator (MTM) quadrangles -40277, -45277, -45272, and -40272 (lat 37.5 degrees S.-47.5 degrees S., long 270 degrees W.-280 degrees W.) cover the eastern portion of the Hellas basin including the boundary between its floor and rim, the distal portions of Dao and Harmakhis Valles, and the deposits of eastern Hellas Planitia. The geologic mapping, at 1:1,000,000-scale from Viking Orbiter, Thermal Emission Imaging System (THEMIS) infrared (IR) and visible (VIS) wavelength, and Mars Orbiter Camera (MOC) narrow-angle images, combined with Mars Orbiter Laser Altimeter (MOLA) topographic data, characterizes the geologic materials and processes that have shaped this region. In particular, the mapping helps to evaluate landforms and deposits resulting from modification of highland terrains by volatile-driven degradation. This mapping study builds on previous mapping in Hellas Planitia and to the east and facilitates comparisons between the geologic history of the east rim, the remainder of the rim, and Hellas Planitia. Specific objectives of our mapping are (1) to reconstruct fluvial systems that dissect the Hellas rim, (2) to characterize the extensions of Dao and Harmakhis Valles onto the basin floor and to identify, if present, sediments these canyons contributed to Hellas Planitia from the rim, and (3) to investigate the mode of origin, age, and history of modification of the boundary between the east rim and Hellas Planitia.

Geologic map of MTM -45252 and-45257 quadrangles, Reull Vallis region of Mars

USGS Publications Warehouse

Mest, Scott C.; Crown, David A.

2003-01-01

Mars Transverse Mercator (MTM) quadrangles -45252 and -45257 (latitude 42.5° S. to 47.5°S., longitude 250° W. to 260° W.) cover a portion of the highlands of Promethei Terra east of Hellas basin. The map area consists of heavily cratered ancient highland materials having moderate to high relief, isolated knobs and massifs of rugged mountainous material, and extensive tracts of smooth and channeled plains. Part of the ~1,500-km-long Reull Vallis outflow system is within the map area. The area also contains surficial deposits, such as the prominent large debris aprons that commonly surround highland massifs. Regional slopes are to the west, toward the Hellas basin, as indicated by topographic maps of Mars. Approximately 60 percent of the surface of Mars is covered by rugged, heavily cratered terrains believed to represent the effects of heavy bombardment in the inner solar system about 4.0 billion years ago. Much of this terrain, including that within the map area, records a long history of modification by tectonism, fluvial processes, mass wasting, and eolian activity. The presence of fluvial features to the east of Hellas basin, including Reull Vallis and other smaller channels, has significant implications for past environmental conditions. The degraded terrains surrounding Hellas basin provide constraints on the role and timing of volatile-driven activity in the evolution of the highlands. Current photogeologic mapping at 1:500,000 scale (see also Mest and Crown, 2002) from analysis of Viking Orbiter images complements previous geomorphic studies of Reull Vallis and other highland outflow systems, drainage networks, and highland debris aprons, as well as regional geologic mapping studies and geologic mapping of Hellas basin as a whole at 1:5,000,000 scale. Viking Orbiter image coverage of the map area generally ranges from 160 to 220 m/pixel; the central part of the map area is covered by higher resolution images of about 47 m/pixel. Crater size-frequency distributions have been compiled to constrain the relative ages of geologic units and determine the timing and duration of inferred geologic processes.

Geologic map of the northern plains of Mars

USGS Publications Warehouse

Tanaka, Kenneth L.; Skinner, James A.; Hare, Trent M.

2005-01-01

The northern plains of Mars cover nearly a third of the planet and constitute the planet's broadest region of lowlands. Apparently formed early in Mars' history, the northern lowlands served as a repository both for sediments shed from the adjacent ancient highlands and for volcanic flows and deposits from sources within and near the lowlands. Geomorphic evidence for extensive tectonic deformation and reworking of surface materials through release of volatiles occurs throughout the northern plains. In the polar region, Planum Boreum contains evidence for the accumulation of ice and dust, and surrounding dune fields suggest widespread aeolian transport and erosion. The most recent regional- and global-scale maps describing the geology of the northern plains are largely based on Viking Orbiter image data (Dial, 1984; Witbeck and Underwood, 1984; Scott and Tanaka, 1986; Greeley and Guest, 1987; Tanaka and Scott, 1987; Tanaka and others, 1992a; Rotto and Tanaka, 1995; Crumpler and others, 2001; McGill, 2002). These maps reveal highland, plains, volcanic, and polar units based on morphologic character, albedo, and relative ages using local stratigraphic relations and crater counts. This geologic map of the northern plains is the first published map that covers a significant part of Mars using topography and image data from both the Mars Global Surveyor and Mars Odyssey missions. The new data provide a fresh perspective on the geology of the region that reveals many previously unrecognizable units, features, and temporal relations. In addition, we adapted and instituted terrestrial mapping methods and stratigraphic conventions that we think result in a clearer and more objective map. We focus on mapping with the intent of reconstructing the history of geologic activity within the northern plains, including deposition, volcanism, erosion, tectonism, impact cratering, and other processes with the aid of comprehensive crater-density determinations. Mapped areas include all plains regions within the northern hemisphere of Mars, as well as an approximately 300-km-wide strip of cratered highland and volcanic regions, which border the plains. Note that not all of the contiguous northern plains are mapped, because some minor parts of Elysium and Amazonis Planitiae lie south of the equator.

Crater Lakes on Mars: Development of Quantitative Thermal and Geomorphic Models

NASA Technical Reports Server (NTRS)

Barnhart, C. J.; Tulaczyk, S.; Asphaug, E.; Kraal, E. R.; Moore, J.

2005-01-01

Impact craters on Mars have served as catchments for channel-eroding surface fluids, and hundreds of examples of candidate paleolakes are documented [1,2] (see Figure 1). Because these features show similarity to terrestrial shorelines, wave action has been hypothesized as the geomorphic agent responsible for the generation of these features [3]. Recent efforts have examined the potential for shoreline formation by wind-driven waves, in order to turn an important but controversial idea into a quantitative, falsifiable hypothesis. These studies have concluded that significant wave-action shorelines are unlikely to have formed commonly within craters on Mars, barring Earth-like weather for approx.1000 years [4,5,6].

Geomorphic Transport Laws and the Statistics of Topography and Stratigraphy

NASA Astrophysics Data System (ADS)

Schumer, R.; Taloni, A.; Furbish, D. J.

2016-12-01

Geomorphic transport laws take the form of partial differential equations in which sediment motion is a deterministic function of slope. The addition of a noise term, representing unmeasurable, or subgrid scale autogenic forcing, reproduces scaling properties similar to those observed in topography, landforms, and stratigraphy. Here we describe a transport law that generalizes previous equations by permitting transport that is local or non-local in addition to different types of noise. More importantly, we use this transport law to link the character of sediment transport to the statistics of topography and stratigraphy. In particular, we link the origin of the Sadler effect to the evolution of the earth surface via a transport law.

Tapping into the Hexagon spy imagery database: A new automated pipeline for geomorphic change detection

NASA Astrophysics Data System (ADS)

Maurer, Joshua; Rupper, Summer

2015-10-01

Declassified historical imagery from the Hexagon spy satellite database has near-global coverage, yet remains a largely untapped resource for geomorphic change studies. Unavailable satellite ephemeris data make DEM (digital elevation model) extraction difficult in terms of time and accuracy. A new fully-automated pipeline for DEM extraction and image orthorectification is presented which yields accurate results and greatly increases efficiency over traditional photogrammetric methods, making the Hexagon image database much more appealing and accessible. A 1980 Hexagon DEM is extracted and geomorphic change computed for the Thistle Creek Landslide region in the Wasatch Range of North America to demonstrate an application of the new method. Surface elevation changes resulting from the landslide show an average elevation decrease of 14.4 ± 4.3 m in the source area, an increase of 17.6 ± 4.7 m in the deposition area, and a decrease of 30.2 ± 5.1 m resulting from a new roadcut. Two additional applications of the method include volume estimates of material excavated during the Mount St. Helens volcanic eruption and the volume of net ice loss over a 34-year period for glaciers in the Bhutanese Himalayas. These results show the value of Hexagon imagery in detecting and quantifying historical geomorphic change, especially in regions where other data sources are limited.

Digital Database of Recently Active Traces of the Hayward Fault, California

USGS Publications Warehouse

Lienkaemper, James J.

2006-01-01

The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Hayward Fault Zone, California. The mapped traces represent the integration of the following three different types of data: (1) geomorphic expression, (2) creep (aseismic fault slip),and (3) trench exposures. This publication is a major revision of an earlier map (Lienkaemper, 1992), which both brings up to date the evidence for faulting and makes it available formatted both as a digital database for use within a geographic information system (GIS) and for broader public access interactively using widely available viewing software. The pamphlet describes in detail the types of scientific observations used to make the map, gives references pertaining to the fault and the evidence of faulting, and provides guidance for use of and limitations of the map. [Last revised Nov. 2008, a minor update for 2007 LiDAR and recent trench investigations; see version history below.

Northern California LIDAR Data: A Tool for Mapping the San Andreas Fault and Pleistocene Marine Terraces in Heavily Vegetated Terrain

NASA Astrophysics Data System (ADS)

Prentice, C. S.; Crosby, C. J.; Harding, D. J.; Haugerud, R. A.; Merritts, D. J.; Gardner, T. W.; Koehler, R. D.; Baldwin, J. N.

2003-12-01

Recent acquisition of airborne LIDAR (also known as ALSM) data covering approximately 418 square kilometers of coastal northern California provides a powerful new tool for mapping geomorphic features related to the San Andreas Fault and coastal uplift. LIDAR data has been previously used in the Puget Lowland region of Washington to identify and map Holocene faults and uplifted shorelines concealed under dense vegetation (Haugerud et al., 2003; see http://pugetsoundlidar.org). Our effort represents the first use of LIDAR data for this purpose along the San Andreas Fault. This data set is the result of a collaborative effort between NASA Solid Earth and Natural Hazards Program, Goddard Space Flight Center, Stennis Space Center, USGS, and TerraPoint, LLC. The coverage extends from near Fort Ross, California, in Sonoma County, along the coast northward to the town of Mendocino, in Mendocino County, and as far inland as about 1-3 km east of the San Andreas Fault. The survey area includes about 70 km of the northern San Andreas Fault under dense redwood forest, and Pleistocene coastal marine terraces both north and south of the fault. The average data density is two laser pulses per square meter, with up to four LIDAR returns per pulse. Returns are classified as ground or vegetation, allowing construction of both canopy-top and bare-earth DEMs with 1.8m grid spacing. Vertical accuracy is better than 20 cm RMSE, confirmed by a network of ground-control points established using high-precision GPS surveying. We are using hillshade images generated from the bare-earth DEMs to begin detailed mapping of geomorphic features associated with San Andreas Fault traces, such as scarps, offset streams, linear valleys, shutter ridges, and sag ponds. In addition, we are using these data in conjunction with field mapping and interpretation of conventional 1:12,000 and 1:6000 scale aerial photographs to map and correlate marine terraces to better understand rates of coastal uplift, and rates of strike-slip motion across the San Andreas Fault.

Polygonal tundra geomorphological change in response to warming alters future CO2 and CH4 flux on the Barrow Peninsula.

PubMed

Lara, Mark J; McGuire, A David; Euskirchen, Eugenie S; Tweedie, Craig E; Hinkel, Kenneth M; Skurikhin, Alexei N; Romanovsky, Vladimir E; Grosse, Guido; Bolton, W Robert; Genet, Helene

2015-04-01

The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate, and extreme scenarios of thermokarst pit formation (10%, 30%, and 50%) reported for Alaskan arctic tundra sites. We developed a 30 × 30 m resolution tundra geomorphology map (overall accuracy:75%; Kappa:0.69) for our ~1800 km² study area composed of ten classes; drained slope, high center polygon, flat-center polygon, low center polygon, coalescent low center polygon, polygon trough, meadow, ponds, rivers, and lakes, to determine their spatial distribution across the Barrow Peninsula. Land-atmosphere CO2 and CH4 flux data were collected for the summers of 2006-2010 at eighty-two sites near Barrow, across the mapped classes. The developed geomorphic map was used for the regional assessment of carbon flux. Results indicate (i) at present during peak growing season on the Barrow Peninsula, CO2 uptake occurs at -902.3 10(6) gC-CO2 day(-1) (uncertainty using 95% CI is between -438.3 and -1366 10(6) gC-CO2 day(-1)) and CH4 flux at 28.9 10(6) gC-CH4 day(-1) (uncertainty using 95% CI is between 12.9 and 44.9 10(6) gC-CH4 day(-1)), (ii) one century of future landscape change associated with the thaw-lake cycle only slightly alter CO2 and CH4 exchange, while (iii) moderate increases in thermokarst pits would strengthen both CO2 uptake (-166.9 10(6) gC-CO2 day(-1)) and CH4 flux (2.8 10(6) gC-CH4 day(-1)) with geomorphic change from low to high center polygons, cumulatively resulting in an estimated negative feedback to warming during peak growing season. © 2014 John Wiley & Sons Ltd.

Applications of Morphochronology to the Active Tectonics of Tibet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryerson, F J; Tapponnier, P; Finkel, R C

2005-01-28

The Himalayas and the Tibetan Plateau were formed as a result of the collision of India and Asia, and provide an excellent opportunity to study the mechanical response of the continental lithosphere to tectonic stress. Geophysicists are divided in their views on the nature of this response advocating either (1) homogeneously distributed deformation with the lithosphere deforming as a fluid continuum or (2) deformation is highly localized with the lithosphere that deforms as a system of blocks. The resolution of this issue has broad implications for understanding the tectonic response of continental lithosphere in general. Homogeneous deformation is supported bymore » relatively low decadal, geodetic slip-rate estimates for the Altyn Tagh and Karakorum Faults. Localized deformation is supported by high millennial, geomorphic slip-rates constrained by both cosmogenic and radiocarbon dating on these faults. Based upon the agreement of rates determined by radiocarbon and cosmogenic dating, the overall linearity of offset versus age correlations, and on the plateau-wide correlation of landscape evolution and climate history, the disparity between geomorphic and geodetic slip-rate determinations is unlikely to be due to the effects of surface erosion on the cosmogenic age determinations. Similarly, based upon the consistency of slip-rates over various observation intervals, secular variations in slip-rate appear to persist no longer than 2000 years and are unlikely to provide reconciliation. Conversely, geodetic and geomorphic slip-rate estimates on the Kunlun fault, which does not have significant splays or associated thrust faults, are in good agreement, indicating that there is no fundamental reason why these complementary geodetic and geomorphic methods should disagree. Similarly, the geodetic and geomorphic estimates of shortening rates across the northeastern edge of the plateau are in reasonable agreement, and the geomorphic rates on individual thrust faults demonstrate a significant eastward decrease in the shortening rate. This rate decrease is consistent with the transfer of slip from the Altyn Tagh Fault (ATF) to genetically-related thrust mountain building at its terminus. Rates on the ATF suggest a similar decrease in rate, but the current data set is too small to be definitive. Overall, the high, late Pleistocene-Holocene, geomorphic slip velocities on the major strike-slip faults of Tibet, suggests that they absorb as much of India's convergence relative to Siberia as the Himalayan Main Frontal Thrust on the southern edge of the plateau.« less

Reclamation Strategies and Geomorphic Outcomes in Coal Surface Mines of Eastern Ohio

NASA Astrophysics Data System (ADS)

Pollock, M.; Jaeger, K. L.

2014-12-01

Coal surface mining is a significant landscape disturbance in the United States. Since 1977, the reclamation of mined lands has been regulated by the Surface Mine Control and Reclamation Act (SMCRA). Prior to the act, many coalfields were left un-reclaimed or partially reclaimed, with highly irregular topology and drainage networks. Under the act, the reverse is often true; adherence to SMCRA often leads to the homogenization of surfaces and channel networks. While both pre and post-SMCRA landscapes are highly altered, they exhibit strongly dissimilar characteristics. We examine pre-SMCRA, post-SMCRA and unmined watersheds at 3 spatial scales in order to compare the geomorphic differences between reclamation strategies. In particular, we attempt to separate anthropogenic factors from pre-existing, natural factors via comparisons to unmined watersheds. Our study design incorporates a 3 scale top-down analysis of 21 independent watersheds (7 of each treatment type). Each watershed has an area of approximately 1km2. All watersheds share similar geography, climate and geology. At the landscape scale, characteristics are derived from 0.762m (2.5ft) resolution Digital Elevation Models (DEMs). At the channel network scale, DEMs, as well as remote sensing data (including the National Wetlands Inventory database) are used. Finally, the reach scale incorporates longitudinal and cross-section surveys (using a total station) as well as a particle size distribution. At each scale, attributes are parameterized for statistical comparison. Post-SMCRA sites are characterized by a general reduction of watershed surface slopes (11.9% median) compared to pre-SMCRA (19.3%) and unmined (19.8%) sites. Both pre and post-SMCRA channel networks are characterized by significant surface impoundments (in the form of remnant headwall trenches on pre-SMCRA sites and engineered retention basins on post-SMCRA sites). Pre-SMCRA outlet reaches have significantly steeper bed slopes (2.79% mean) than both post-SMCRA (1.72% mean) and unmined (1.67% mean) reaches (1-way ANOVA p=0.0488 n=19). Our results demonstrate the differential alterations resulting from these reclamation strategies, which may lead to alteration of long-term geomorphic processes. Further investigations of hydrology and sediment transport are needed.

Image-based terrain modeling with thematic mapper applied to resolving the limit of Holocene Lake expansion in the Great Salt Lake Desert, Utah, part 1

NASA Technical Reports Server (NTRS)

Merola, John A.

1989-01-01

The LANDSAT Thematic Mapper (TM) scanner records reflected solar energy from the earth's surface in six wavelength regions, or bands, and one band that records emitted energy in the thermal region, giving a total of seven bands. Useful research was extracted about terrain morphometry from remote sensing measurements and this information is used in an image-based terrain model for selected coastal geomorphic features in the Great Salt Lake Desert (GSLD). Technical developments include the incorporation of Aerial Profiling of Terrain System (APTS) data in satellite image analysis, and the production and use of 3-D surface plots of TM reflectance data. Also included in the technical developments is the analysis of the ground control point spatial distribution and its affects on geometric correction, and the terrain mapping procedure; using satellite data in a way that eliminates the need to degrade the data by resampling. The most common approach for terrain mapping with multispectral scanner data includes the techniques of pattern recognition and image classification, as opposed to direct measurement of radiance for identification of terrain features. The research approach in this investigation was based on an understanding of the characteristics of reflected light resulting from the variations in moisture and geometry related to terrain as described by the physical laws of radiative transfer. The image-based terrain model provides quantitative information about the terrain morphometry based on the physical relationship between TM data, the physical character of the GSLD, and the APTS measurements.

Some unique surface patterns on ignimbrites on Earth: A "bird's eye" view as a guide for planetary mappers

NASA Astrophysics Data System (ADS)

de Silva, Shanaka L.; Bailey, John E.

2017-08-01

Observations of terrestrial analogs are critical to aiding planetary mappers in interpreting surface lithologies on other planets. For instance, the presence of ignimbrites on Mars has been debated for over three decades and is supported by analogy with deposits on Earth. Critical evidence includes the geomorphic and surface expression of the deposits, and those in the Central Andes of South America are amongst the most-cited analogs. Herein we describe some prominent surface textures and patterns seen in ignimbrites on the scale of high-resolution remotely sensed data (10-1 m per pixel). These include pervasive joints and fractures that contribute to yardang form and development as well as prominent mounds, fissures, and fracture networks ("spiders", "bugs", "boxworks") on ignimbrite surfaces. While all these features are related to intrinsic cooling and degassing processes, the involvement of external water buried by hot pyroclastic flows enhances fumarolic activity, advective cooling, and joint development. Observations of these geomorphic expressions using remote sensing are only possible with the highest resolution data and limited surface erosion. For Mars, where similarly high resolution datasets are available (for example, the High Resolution Imaging Sensor Experiment or HiRISE) extensive dust cover may limit the recognition of similar features there. However significant relief on some of these features on Earth indicate they might still be detectable on Mars.

Combining Mechanistic Approaches for Studying Eco-Hydro-Geomorphic Coupling

NASA Astrophysics Data System (ADS)

Francipane, A.; Ivanov, V.; Akutina, Y.; Noto, V.; Istanbullouglu, E.

2008-12-01

Vegetation interacts with hydrology and geomorphic form and processes of a river basin in profound ways. Despite recent advances in hydrological modeling, the dynamic coupling between these processes is yet to be adequately captured at the basin scale to elucidate key features of process interaction and their role in the organization of vegetation and landscape morphology. In this study, we present a blueprint for integrating a geomorphic component into the physically-based, spatially distributed ecohydrological model, tRIBS- VEGGIE, which reproduces essential water and energy processes over the complex topography of a river basin and links them to the basic plant life regulatory processes. We present a preliminary design of the integrated modeling framework in which hillslope and channel erosion processes at the catchment scale, will be coupled with vegetation-hydrology dynamics. We evaluate the developed framework by applying the integrated model to Lucky Hills basin, a sub-catchment of the Walnut Gulch Experimental Watershed (Arizona). The evaluation is carried out by comparing sediment yields at the basin outlet, that follows a detailed verification of simulated land-surface energy partition, biomass dynamics, and soil moisture states.

Human-induced changes in animal populations and distributions, and the subsequent effects on fluvial systems

NASA Astrophysics Data System (ADS)

Butler, David R.

2006-09-01

Humans have profoundly altered hydrological pathways and fluvial systems through their near-extirpation of native populations of animal species that strongly influenced hydrology and removal of surface sediment, and through the introduction of now-feral populations of animals that bring to bear a suite of different geomorphic effects on the fluvial system. In the category of effects of extirpation, examples are offered through an examination of the geomorphic effects and former spatial extent of beavers, bison, prairie dogs, and grizzly bears. Beavers entrapped hundreds of billions of cubic meters of sediment in North American stream systems prior to European contact. Individual bison wallows, that numbered in the range of 100 million wallows, each displaced up to 23 m 3 of sediment. Burrowing by prairie dogs displaced more than 5000 kg and possibly up to 67,500 kg of sediment per hectare. In the category of feral populations, the roles of feral rabbits, burros and horses, and pigs are highlighted. Much work remains to adequately quantify the geomorphic effects animals have on fluvial systems, but the influence is undeniable.

Spectral roughness of glaciated bedrock geomorphic surfaces: Implications for glacier sliding

NASA Astrophysics Data System (ADS)

Hubbard, Bryn; Siegert, Martin J.; McCarroll, Danny

2000-09-01

A microroughness meter (MRM) was used to measure the high-frequency roughness of a number of geomorphic surfaces in the forefield of Glacier de Tsanfleuron, Switzerland. Resulting spectral power densities are added to low-frequency spectra, measured by electro-optical distance meter (EDM), to generate composite roughness spectra that include almost 5 orders of magnitude of roughness in the frequency domain. These are used to define two roughness indices: a general index of bed roughness is defined as the integral of the raw, spectral power densities, and a sliding-related index of bed roughness is defined as the integral of the spectral power densities weighted to account for the optimum dependence of glacier sliding speed on hummock wavelength. Results indicate that MRM-measured geomorphic components vary in roughness by 3 orders of magnitude, principally depending on the surface microenvironment measured and profile orientation relative to the direction of former ice flow. Both MRM- and EDM-measured roughnesses are lower parallel to the direction of former ice flow than perpendicular to it. Composite roughness spectra consequently indicate that the glacier bed is smoothed in the direction of former ice flow at all horizontal scales from 1 mm to 40 m, typically resulting in an order of magnitude decrease in sliding-related roughness relative to that measured perpendicular to ice flow. Comparison of data from two survey sites located adjacent to, and ˜1.2 km from, the current glacier margin indicates that postglacial subaerial weathering homogenizes bedrock roughness, in particular reducing high-frequency, flow-orthogonal roughness. Accounting for the effect of 28% ice-bedrock separation over one of the profiles reduces net, sliding-dependent roughness by between 27% and 43%, depending on the transition wave number used.

Eco-geomorphic controls on slope stability

NASA Astrophysics Data System (ADS)

Hales, T.; Ford, C.; Hwang, T.; Vose, J.; Band, L.

2009-04-01

Vegetation controls soil-mantled landscape evolution primarily through growth of roots into soil and rock. Root-soil interactions affect the spatial distribution and rate of shallow landsliding and other hillslope processes. Yet the distribution and tensile strength of roots depends on a number of geomorphically-influenced parameters, including soil moisture. Our field-based study investigated the effects of topography on root distributions, tensile strengths, and cohesion. Systematic differences in plant species distribution and soil properties are found in the hollow-nose topography of soil-mantled landscapes; with hollows containing thick colluvial soils and mesic tree species and noses containing thinner, more differentiated soils and more xeric species. We investigated whether these topographic variations in geomorphic and ecologic properties affected the spatial distribution of root cohesion by measuring the distribution and tensile strength of roots from soil pits dug downslope of fifteen individual trees in the Coweeta Hydrologic Laboratory, North Carolina. Our soil pits were located to capture variance in plant species (10 species total), topographic positions (nose, hollow), and sizes (a range of DBH between 5 cm and 60 cm). Root tensile strengths showed little variance with different species, but showed strong differences as a function of topography, with nose roots stronger than hollow roots. Similarly, within species, root cellulose content was systematically greater in trees on nose positions compared to those in hollows. For all species, roots were concentrated close to the soil surface (at least 70% of biomass occurred within 50 cm of the surface) and variations in this pattern were primarily a function of topographic position. Hollow roots were more evenly distributed in the soil column than those on noses, yet trees located on noses had higher mean root cohesion than those in hollows because of a higher root tensile force. These data provide an empirical basis for the development of simple geomorphic transport laws that explicitly include vegetation.

Evaluation of the Location and Recency of Faulting Near Prospective Surface Facilities in Midway Valley, Nye County, Nevada

USGS Publications Warehouse

Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

2001-01-01

Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern zone of fractures is within Quaternary alluvial sediments, but no bedrock was encountered in trenches and soil pits in this part of the prospective surface facilities site; thus, the direct association of this zone with one or more bedrock faults is uncertain. No displacement of lithologic contacts and soil horizons could be detected in the fractured Quaternary deposits. The results of these investigations imply the absence of any appreciable late Quaternary faulting activity at the prospective surface-facilities site.

Geologic, geomorphic, and meteorological aspects of debris flows triggered by Hurricanes Frances and Ivan during September 2004 in the Southern Appalachian Mountains of Macon County, North Carolina (southeastern USA)

USGS Publications Warehouse

Wooten, R.M.; Gillon, K.A.; Witt, A.C.; Latham, R.S.; Douglas, T.J.; Bauer, J.B.; Fuemmeler, S.J.; Lee, L.G.

2008-01-01

In September 2004, rain from the remnants of Hurricanes Frances and Ivan triggered at least 155 landslides in the Blue Ridge Mountains of North Carolina. At least 33 debris flows occurred in Macon County, causing 5 deaths, destroying 16 homes, and damaging infrastructure. We mapped debris flows and debris deposits using a light-detecting and ranging digital elevation model, remote imagery and field studies integrated in a geographic information system. Evidence of past debris flows was found at all recent debris flow sites. Orographic rainfall enhancement along topographic escarpments influenced debris flow frequency at higher elevations. A possible trigger for the Wayah and fatal Peeks Creek debris flows was a spiral rain band within Ivan that moved across the area with short duration rainfall rates of 150-230 mm/h. Intersecting bedrock structures in polydeformed metamorphic rock influence the formation of catchments within structural-geomorphic domains where debris flows originate. ?? 2007 Springer-Verlag.

Analysis and Modeling of Complex Geomorphic Systems: Technique Development, Data Collection, and Application to Rangeland Terrain

DTIC Science & Technology

2008-10-01

attempts to measure the long-term distribution of stor- age time have relied unrealistic assumptions, but two recent studies suggest a new approach. As...sediment 10 age . Everitt (1968) mapped the age distribution of cottonwoods along a 34 km stretch of the Little Missouri River in North Dakota...Dietrich et al. (1982) applied Erikssons (1971) method to estimate the residence time distribution from Everitts age distribution. Somewhat mysteriously

Geologic, geomorphic, and meteorological aspects of debris flows triggered by Hurricanes Frances and Ivan during September 2004 in the Southern Appalachian Mountains of Macon County, North Carolina (southeastern USA)

Treesearch

R. M. Wooten; K. A. Gillon; A. C. Witt; R. S. Latham; T. J. Douglas; J. B. Bauer; S. J. Fuemmeler; L. G. Lee

2008-01-01

In September 2004, rain from the remnants of Hurricanes Frances and Ivan triggered at least 155 landslides in the Blue Ridge Mountains of North Carolina. At least 33 debris flows occurred in Macon County, causing 5 deaths, destroying 16 homes, and damaging infrastructure. We mapped debris flows and debris deposits using a light-detecting and ranging digital elevation...

Preliminary geologic map of the Sleeping Butte volcanic centers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowe, B.M.; Perry, F.V.

1991-07-01

The Sleeping Butte volcanic centers comprise two, spatially separate, small-volume (<0.1 km{sup 3}) basaltic centers. The centers were formed by mildly explosive Strombolian eruptions. The Little Black Peak cone consists of a main scoria cone, two small satellitic scoria mounds, and associated lobate lava flows that vented from sites at the base of the scoria cone. The Hidden Cone center consists of a main scoria cone that developed on the north-facing slope of Sleeping Butte. The center formed during two episodes. The first included the formation of the main scoria cone, and venting of aa lava flows from radial dikesmore » at the northeast base of the cone. The second included eruption of scoria-fall deposits from the summit crater. The ages of the Little Black Peak and the Hidden Cone are estimated to be between 200 to 400 ka based on the whole-rock K-Ar age determinations with large analytical undertainty. This age assignment is consistent with qualitative observations of the degree of soil development and geomorphic degradation of volcanic landforms. The younger episode of the Hidden Cone is inferred to be significantly younger and probably of Late Pleistocene or Holocene age. This is based on the absence of cone slope rilling, the absence of cone-slope apron deposits, and erosional unconformity between the two episodes, the poor horizon- development of soils, and the presence of fall deposits on modern alluvial surfaces. Paleomagnetic data show that the centers record similar but not identical directions of remanent magnetization. Paleomagnetic data have not been obtained for the youngest deposits of the Hidden Cone center. Further geochronology, soils, geomorphic, and petrology studies are planned of the Sleeping Butte volcanic centers 20 refs., 3 figs.« less

Relative timing of last glacial maximum and late-glacial events in the central tropical Andes

NASA Astrophysics Data System (ADS)

Bromley, Gordon R. M.; Schaefer, Joerg M.; Winckler, Gisela; Hall, Brenda L.; Todd, Claire E.; Rademaker, Kurt M.

2009-11-01

Whether or not tropical climate fluctuated in synchrony with global events during the Late Pleistocene is a key problem in climate research. However, the timing of past climate changes in the tropics remains controversial, with a number of recent studies reporting that tropical ice age climate is out of phase with global events. Here, we present geomorphic evidence and an in-situ cosmogenic 3He surface-exposure chronology from Nevado Coropuna, southern Peru, showing that glaciers underwent at least two significant advances during the Late Pleistocene prior to Holocene warming. Comparison of our glacial-geomorphic map at Nevado Coropuna to mid-latitude reconstructions yields a striking similarity between Last Glacial Maximum (LGM) and Late-Glacial sequences in tropical and temperate regions. Exposure ages constraining the maximum and end of the older advance at Nevado Coropuna range between 24.5 and 25.3 ka, and between 16.7 and 21.1 ka, respectively, depending on the cosmogenic production rate scaling model used. Similarly, the mean age of the younger event ranges from 10 to 13 ka. This implies that (1) the LGM and the onset of deglaciation in southern Peru occurred no earlier than at higher latitudes and (2) that a significant Late-Glacial event occurred, most likely prior to the Holocene, coherent with the glacial record from mid and high latitudes. The time elapsed between the end of the LGM and the Late-Glacial event at Nevado Coropuna is independent of scaling model and matches the period between the LGM termination and Late-Glacial reversal in classic mid-latitude records, suggesting that these events in both tropical and temperate regions were in phase.

Reconnaissance investigation of the alluvial gold deposits in the North Takhar Area of Interest, Takhar Province, Afghanistan

USGS Publications Warehouse

Chirico, Peter G.; Malpeli, Katherine C.; Moran, Thomas W.

2013-01-01

This study is a reconnaissance assessment of the alluvial gold deposits of the North Takhar Area of Interest (AOI) in Takhar Province, Afghanistan. Soviet and Afghan geologists collected data and calculated the gold deposit reserves in Takhar Province in the 1970s, prior to the development of satellite-based remote-sensing platforms and new methods of geomorphic mapping. The purpose of this study was to integrate new mapping techniques with previously collected borehole sampling and concentration sampling data and geomorphologic interpretations to reassess the alluvial gold placer deposits in the North Takhar AOI. Through a combination of historical borehole and cross-section data and digital terrain modeling, the Samti, Nooraba-Khasar-Anjir, and Kocha River placer deposits were reassessed. Resource estimates were calculated to be 20,927 kilograms (kg) for Samti, 7,626 kg for Nooraba-Khasar-Anjir, 160 kg for the mouth of the Kocha, 1,047 kg for the lower Kocha, 113 kg for the middle Kocha, and 168 kg for the upper Kocha. Previous resource estimates conducted by the Soviets for the Samti and Nooraba-Khasar-Anjir deposits estimated 30,062 kg and 802 kg of gold, respectively. This difference between the new estimates and previous estimates results from the higher resolution geomorphic model and the interpretation of areas outside of the initial work zone studied by Soviet and Afghan geologists.

Reconnaissance investigation of the placer gold deposits in the Zarkashan Area of Interest, Ghazni Province, Afghanistan

USGS Publications Warehouse

Malpeli, Katherine C.; Chirico, Peter G.; McLoughlin, Isabel H.

2013-01-01

This study is a reconnaissance investigation of the placer gold deposits in the Zarkashan Area of Interest (AOI) in Ghazni Province, Afghanistan. Detailed investigations of the Zarkashan gold deposits were conducted by Soviet and Afghan geologists in the 1960s and 1970s, prior to the development of satellite-based remote-sensing platforms and new methods of geomorphic mapping. The purpose of this study was to integrate new mapping techniques with previously collected concentration and borehole sampling data and geomorphologic interpretations to reassess the placer gold deposits in the Zarkashan AOI. A methodology combining the collection and analysis of historical sampling data, digital database development, hydrologic analysis, and geomorphic modeling was used. The analysis led to the reinterpretation of four gold-bearing seams along the Zarkashan River, and the calculation of an estimated gold reserve of approximately 3,000 kilograms (kg). This estimate is approximately 1,500 kg greater than the Soviet estimate. The result differs in large part due to the reinterpretation of the seams based on a much lower cutoff grade of 100 mg/m3. Because cutoff grade is dependent in part on the price of gold, the sevenfold increase in the price of gold since the undertaking of the Soviet investigation warranted our re-evaluation of their 500 mg/m3 cutoff grade.

Geology Report: Area 3 Radioactive Waste Management Site DOE/Nevada Test Site, Nye County, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

NSTec Environmental Management

2006-07-01

Surficial geologic studies near the Area 3 Radioactive Waste Management Site (RWMS) were conducted as part of a site characterization program. Studies included evaluation of the potential for future volcanism and Area 3 fault activity that could impact waste disposal operations at the Area 3 RWMS. Future volcanic activity could lead to disruption of the Area 3 RWMS. Local and regional studies of volcanic risk indicate that major changes in regional volcanic activity within the next 1,000 years are not likely. Mapped basalts of Paiute Ridge, Nye Canyon, and nearby Scarp Canyon are Miocene in age. There is a lackmore » of evidence for post-Miocene volcanism in the subsurface of Yucca Flat, and the hazard of basaltic volcanism at the Area 3 RWMS, within the 1,000-year regulatory period, is very low and not a forseeable future event. Studies included a literature review and data analysis to evaluate unclassified published and unpublished information regarding the Area 3 and East Branch Area 3 faults mapped in Area 3 and southern Area 7. Two trenches were excavated along the Area 3 fault to search for evidence of near-surface movement prior to nuclear testing. Allostratigraphic units and fractures were mapped in Trenches ST02 and ST03. The Area 3 fault is a plane of weakness that has undergone strain resulting from stress imposed by natural events and underground nuclear testing. No major vertical displacement on the Area 3 fault since the Early Holocene, and probably since the Middle Pleistocene, can be demonstrated. The lack of major displacement within this time frame and minimal vertical extent of minor fractures suggest that waste disposal operations at the Area 3 RWMS will not be impacted substantially by the Area 3 fault, within the regulatory compliance period. A geomorphic surface map of Yucca Flat utilizes the recent geomorphology and soil characterization work done in adjacent northern Frenchman Flat. The approach taken was to adopt the map unit boundaries (line work) of Swadley and Hoover (1990) and re-label these with map unit designations like those in northern Frenchman Flat (Huckins-Gang et al, 1995a,b,c; Snyder et al, 1995a,b,c,d).« less

Recently Active Traces of the Berryessa Fault, California: A Digital Database

USGS Publications Warehouse

Lienkaemper, James J.

2012-01-01

The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Berryessa section and parts of adjacent sections of the Green Valley Fault Zone, California. The location and recency of the mapped traces is primarily based on geomorphic expression of the fault as interpreted from large-scale 2010 aerial photography and from 2007 and 2011 0.5 and 1.0 meter bare-earth LiDAR imagery (that is, high-resolution topographic data). In a few places, evidence of fault creep and offset Holocene strata in trenches and natural exposures have confirmed the activity of some of these traces. This publication is formatted both as a digital database for use within a geographic information system (GIS) and for broader public access as map images that may be browsed on-line or download a summary map. The report text describes the types of scientific observations used to make the map, gives references pertaining to the fault and the evidence of faulting, and provides guidance for use of and limitations of the map.

Nitrogen dynamics at the ground water-surface water interface of a degraded urban stream

EPA Science Inventory

Urbanization degrades stream ecosystems by altering hydrology and nutrient dynamics. We investigated temporal and spatial patterns in biogeochemistry and hydrology in and near the stream channel of a geomorphically degraded urban stream of Baltimore County, Maryland, USA. Our o...

PRE-RESTORATION GEOMORPHIC AND SEDIMENT CONDITIONS OF MINEBANK RUN, BALTIMORE COUNTY, MARYLAND

EPA Science Inventory

Urban streams frequently undergo severe incision and erosion due to flashy streamflows caused by impervious surfaces in the watershed. Such streamflows can lead to unstable sediment dynamics that can limit options for urban stream restoration. The U.S. Environmental Protection ...

Verifying mapping, monitoring and modeling of fine sediment pollution sources in West Maui, Hawai'i, USA

NASA Astrophysics Data System (ADS)

Cerovski-Darriau, C.; Stock, J. D.

2017-12-01

Coral reef ecosystems, and the fishing and tourism industries they support, depend on clean waters. Fine sediment pollution from nearshore watersheds threatens these enterprises in West Maui, Hawai'i. To effectively mitigate sediment pollution, we first have to know where the sediment is coming from, and how fast it erodes. In West Maui, we know that nearshore sediment plumes originate from erosion of fine sand- to silt-sized air fall deposits where they are exposed by grazing, agriculture, or other disturbances. We identified and located these sediment sources by mapping watershed geomorphological processes using field traverses, historic air photos, and modern orthophotos. We estimated bank lowering rates using erosion pins, and other surface erosion rates were extrapolated from data collected elsewhere on the Hawaiian Islands. These measurements and mapping led to a reconnaissance sediment budget which showed that annual loads are dominated by bank erosion of legacy terraces. Field observations during small storms confirm that nearshore sediment plumes are sourced from bank erosion of in-stream, legacy agricultural deposits. To further verify this sediment budget, we used geochemical fingerprinting to uniquely identify each potential source (e.g. stream banks, agricultural fields, roads, other human modified soils, and hillslopes) from the Wahikuli watershed (10 km2) and analyzed the fine fraction using ICP-MS for elemental geochemistry. We propose to apply this the fingerprinting results to nearshore suspended sediment samples taken during storms to identify the proportion of sediment coming from each source. By combining traditional geomorphic mapping, monitoring and geochemistry, we hope to provide a powerful tool to verify the primary source of sediment reaching the nearshore.

Hydropodelogy From the Pedon to the Landscape: Challenges and Accomplishments in the National Cooperative Soil Survey

NASA Astrophysics Data System (ADS)

Hammer, D.; Richardson, J.; Hempel, J.; Market, P.

2005-12-01

American pedology has focused on the National Cooperative Soil Survey. Primary responsibility rests with the U.S. Department of Agriculture. The primary goals, are legislatively mandated, are to map the country's soils, make interpretations, provide information to clients, maintain and market the soil survey. The first goal is near completion and focus is shifting to the other three. Concomitantly, American pedological science is being impacted by several conditions: technological advances; land use changes at unprecedented scales and magnitudes; a burgeoning population increasingly "separated" from the land; and a major emphasis in universities upon biological ("life") sciences at the DNA scale - as if soil, nutrients and water are not life essentials. Effects of the Flood of 1993 and Hurricane Katrina suggest that humans do not understand earth/climate interactions, particularly climatic extremes. Pedologists know the focus on soil classification and mapping was at the expense of understanding processes. Hydropedology is a holistic approach to understanding soil and geomorphic process in order to predict the impacts of perturbations. Water movement on and in the soil is the primary mechanism of distributing and altering sediments and chemicals (pedogenesis), and depends for its success upon understanding that the soil profile is the record of developmental history at that landscape site. Hydropedologists believe soil scientists can use pedons (point data) from appropriate locations from flownets in complex landscapes to extrapolate processes. This is the "pedotransfer function" concept. Technological advances are coupled with the existing soil survey information to create important soil-landscape interpretations at a variety of scales. Early results have been very successful. Quantification of soil systems can be classified broadly into three categories; hard data, soft data and tacit knowledge. "Hard data" are measured numbers, and include such attributes as pH, texture, cation exchange capacity and event-specific rainfall. "Soft data" include soil maps, SSURGO data and climate maps. Soft data are combinations of observations, measurements and inferences that produce maps and models at various scales. "Tacit knowledge" is human understanding that results from focused experience within a system. A skilled soil scientist with tacit knowledge specific to a particular region can combination hard and soft data to develop important and useful interpretations and predictions. Illustrations from natural and urban settings will be provided. Soils and climate are temporally and spatially variable at all scales. Soil systems respond differently to different climates and perturbations. For example, the recent pluvial period in the Prairie Pothole region is changing surface soil sodium concentrations and locations and sizes of discharge wetlands. This is a relatively short-term response to a regional climate shift. Climatic shift in Oxisol landscapes will have little effect on soil cations. To optimize soil interpretations, focus must be on quantifying region-specific "dynamic" soil, geomorphic and climatic attributes. Recognizing these needs, the National Cooperative Soil Survey will develop regional watershed projects that focus on quantifying soil-water relationships that can be used at a variety of scales.

Geomorphic Segmentation, Hydraulic Geometry, and Hydraulic Microhabitats of the Niobrara River, Nebraska - Methods and Initial Results

USGS Publications Warehouse

Alexander, Jason S.; Zelt, Ronald B.; Schaepe, Nathaniel J.

2009-01-01

The Niobrara River of Nebraska is a geologically, ecologically, and economically significant resource. The State of Nebraska has recognized the need to better manage the surface- and ground-water resources of the Niobrara River so they are sustainable in the long term. In cooperation with the Nebraska Game and Parks Commission, the U.S. Geological Survey is investigating the hydrogeomorphic settings and hydraulic geometry of the Niobrara River to assist in characterizing the types of broad-scale physical habitat attributes that may be of importance to the ecological resources of the river system. This report includes an inventory of surface-water and ground-water hydrology data, surface water-quality data, a longitudinal geomorphic segmentation and characterization of the main channel and its valley, and hydraulic geometry relations for the 330-mile section of the Niobrara River from Dunlap Diversion Dam in western Nebraska to the Missouri River confluence. Hydraulic microhabitats also were analyzed using available data from discharge measurements to demonstrate the potential application of these data and analysis methods. The main channel of the Niobrara was partitioned into three distinct fluvial geomorphic provinces: an upper province characterized by open valleys and a sinuous, equiwidth channel; a central province characterized by mixed valley and channel settings, including several entrenched canyon reaches; and a lower province where the valley is wide, yet restricted, but the river also is wide and persistently braided. Within the three fluvial geomorphic provinces, 36 geomorphic segments were identified using a customized, process-orientated classification scheme, which described the basic physical characteristics of the Niobrara River and its valley. Analysis of the longitudinal slope characteristics indicated that the Niobrara River longitudinal profile may be largely bedrock-controlled, with slope inflections co-located at changes in bedrock type at river level. Hydraulic geometry relations indicated that local (at-a-station) channel adjustments of the Niobrara River to changing discharge are accommodated mainly by changes in velocity, and streamwise adjustments are accommodated through changes in channel width. Downstream hydraulic geometry relations are in general agreement with values previously published for rivers of the Great Plains, but coefficients are likely skewed low because the locations of the streamflow-gaging stations used in this analysis are located at natural or engineered constrictions and may not be accurately representing downstream adjustment processes of the Niobrara River. A demonstration analysis of hydraulic microhabitat attributes at a single station indicated that changes in velocity-related habitat types is the primary microhabitat adjustment over a range of discharges, but the magnitude of that adjustment for any particular discharge is temporally variable.

Monitoring Inflation and Emplacement During the 2014-2015 Kilauea Lava Flow With an Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Perroy, R. L.; Turner, N.; Hon, K. A.; Rasgado, V.

2015-12-01

Unmanned aerial vehicles (UAVs) provide a powerful new tool for collecting high resolution on-demand spatial data over volcanic eruptions and other active geomorphic processes. These data can be used to improve hazard forecasts and emergency response efforts, and also allow users to economically and safely observe and quantify lava flow inflation and emplacement on spatially and temporally useful scales. We used a small fixed-wing UAV with a modified point-and-shoot camera to repeatedly map the active front of the 2014-2015 Kīlauea lava flow over a one-month period in late 2014, at times with a two-hour repeat interval. An additional subsequent flight was added in July, 2015. We used the imagery from these flights to generate a time-series of 5-cm resolution RGB and near-infrared orthoimagery mosaics and associated digital surface models using structure from motion. Survey-grade positional control was provided by ground control points with differential GPS. Two topographic transects were repeatedly surveyed across the flow surface, contemporaneously with UAV flights, to independently confirm topographic changes observed in the UAV-derived surface models. Vertical errors were generally 10 cm. Inside our 50 hectare study site, the flow advanced at a rate of 0.47 hectares/day during the first three weeks of observations before abruptly stalling out <200 m from Pahoa Village road. Over 150,000 m3of lava were added to the study site during our period of observations, with maximum vertical inflation >4 m. New outbreak areas, both on the existing flow surface and along the flow margins, were readily mapped across the study area. We detected sinuous growing inflation ridges within the flow surface that correlated with subsequent outbreaks of new lava, suggesting that repeat UAV flights can provide a means of better predicting pahoehoe lava flow behavior over flat or uneven topography. Our results show that UAVs can generate accurate and digital surface models quickly and inexpensively over rapidly changing active pahoehoe lava flows.

Geomorphic features of surface ruptures associated with the 2016 Kumamoto earthquake in and around the downtown of Kumamoto City, and implications on triggered slip along active faults

NASA Astrophysics Data System (ADS)

Goto, Hideaki; Tsutsumi, Hiroyuki; Toda, Shinji; Kumahara, Yasuhiro

2017-02-01

The 30-km-long surface ruptures associated with the M w 7.0 ( M j 7.3) earthquake at 01:25 JST on April 16 in Kumamoto Prefecture appeared along the previously mapped 100-km-long active fault called the Futagawa-Hinagu fault zone (FHFZ). The surface ruptures appeared to have extended further west out of the main FHFZ into the Kumamoto Plain. Although InSAR analysis by Geospatial Information Authority of Japan (GSI) indicated coseismic surface deformation in and around the downtown of Kumamoto City, the surface ruptures have not been clearly mapped in the central part of the Kumamoto Plain, and whether there are other active faults other than the Futagawa fault in the Kumamoto Plain remained unclear. We produced topographical stereo images (anaglyph) from 5-m-mesh digital elevation model of GSI, which was generated from light detection and ranging data. We interpreted them and identified that several SW-sloping river terraces formed after the deposition of the pyroclastic flow deposits related to the latest large eruption of the Aso caldera (86.8-87.3 ka) are cut and deformed by several NW-trending flexure scarps down to the southwest. These 5.4-km-long scarps that cut across downtown Kumamoto were identified for the first time, and we name them as the Suizenji fault zone. Surface deformation such as continuous cracks, tilts, and monoclinal folding associated with the main shock of the 2016 Kumamoto earthquake was observed in the field along the fault zone. The amount of vertical deformation ( 0.1 m) along this fault associated with the 2016 Kumamoto earthquake was quite small compared to the empirically calculated coseismic slip (0.5 m) based on the fault length. We thus suggest that the slip on this fault zone was triggered by the Kumamoto earthquake, but the fault zone has potential to generate an earthquake with larger slip that poses a high seismic risk in downtown Kumamoto area.[Figure not available: see fulltext.

New insights into the geodiversity of the southeast Indian Ocean seafloor revealed by Malaysia Airlines flight MH370 search data

NASA Astrophysics Data System (ADS)

Picard, K.; Brooke, B. B.; Harris, P. T.; Siwabessy, J. P. W.; Coffin, M. F.; Tran, M.; Spinoccia, M.; Weales, J.; Macmillan-Lawler, M.; Sullivan, J.

2017-12-01

A large multibeam echo sounder (MBES) dataset (710, 000 km2, inclusive of transit data) was acquired in the SE Indian Ocean to assist the search for Malaysia Airlines Flight 370 (MH370). Here, we present the results of a geomorphic analysis of this new data and compare with the Global Seafloor Geomorphic Features Map (GSFM) that is based on coarser resolution satellite-derived bathymetry data. The analyses show that abyssal plains and basins are significantly more rugged than their representation in the GSFM, with a 20% increase in the extent of hills and mountains. The new model also reveals four times more seamounts than presented in the GSFM, suggesting a greater number of these features than previously estimated for the broader region and indeed globally. This is important considering the potential ecological significance of these high-relief structures. Analyses of the new data also enabled knolls, fans, valleys, canyons, troughs and holes to be identified, doubling the number of discrete features mapped and revealing the true geodiversity of the deep ocean in this area. This high-resolution mapping of the seafloor also provides new insights into the geological evolution of the region, both in terms of structural, tectonic, and sedimentary processes. For example, sub-parallel ridges extend over approximately 20% of the area mapped and their form and alignment provide valuable insight into Southeast Indian Ridge seafloor spreading processes. Rifting is recorded along the Broken Ridge - Diamantina Escarpment, with rift blocks and well-bedded sedimentary bedrock exposures discernible down to 2,400 m water depth. Ocean floor sedimentary processes are represented in sediment mass transport features, especially along and north of Broken Ridge, and pockmarks (the finest-scale features mapped) south of Diamantina Trench. The new MBES data highlight the complexity of the search area and serve to demonstrate how little we know about the 85-90% of the ocean floor that has not been mapped with this technology. The availability of high-resolution and accurate maps of the ocean floor can clearly provide new insights into the Earth's geological evolution, modern ocean floor processes, and the location of sites that are likely to have relatively high biodiversity.

Geomorphic Evidence for Martian Ground Ice and Climate Change

NASA Technical Reports Server (NTRS)

Kanner, L. C.; Allen, C. C.; Bell, M. S.

2004-01-01

Recent results from gamma-ray and neutron spectrometers on Mars Odyssey indicate the presence of a hydrogen-rich layer tens of centimeters thick in the uppermost meter in high latitudes (>60 ) on Mars. This hydrogen-rich layer correlates to regions of ice stability. Thus, the subsurface hydrogen is thought to be water ice constituting 35+/- 15% by weight near the north and south polar regions. We refine the location of subsurface ice deposits at a < km scale by combining existing spectroscopy data with surface features indicative of subsurface ice. A positive correlation between spectroscopy data and geomorphic ice indicators has been previously suggested for high latitudes. Here we expand the comparative study to northern mid latitudes (30 deg.N- 65 deg.N).

Coastal monitoring solutions of the geomorphological response of beach-dune systems using multi-temporal LiDAR datasets (Vendée coast, France)

NASA Astrophysics Data System (ADS)

Le Mauff, Baptiste; Juigner, Martin; Ba, Antoine; Robin, Marc; Launeau, Patrick; Fattal, Paul

2018-03-01

Three beach and dune systems located in the northeastern part of the Bay of Biscay in France were monitored over 5 years with a time series of three airborne LiDAR datasets. The three study sites illustrate a variety of morphological beach types found in this region. Reproducible monitoring solutions adapted to basic and complex beach and dune morphologies using LiDAR time series were investigated over two periods bounded by the three surveys. The first period (between May 2008 and August 2010) is characterized by a higher prevalence of storm events, and thus has a greater potential for eroding the coast, than the second period (between August 2010 and September 2013). During the first period, the central and northeastern part of the Bay of Biscay was notably impacted by Storm Xynthia, with water levels and wave heights exceeding the 10-year return period and 1-year return period, respectively. Despite differences in dune morphology between the sites, the dune crest (Dhigh) and the dune base (Dlow) are efficiently extracted from each DEM. Based on the extracted dune base, an original shoreline mobility indicator is built displaying a combination of the horizontal and vertical migrations of this geomorphic indicator between two LiDAR datasets. A 'Geomorphic Change Detection' is also completed by computing DEMs of Difference (DoD) resulting in segregated maps of erosion and deposition and sediment budgets. Accounting for the accuracy of LiDAR datasets, a probabilistic approach at a 95% confidence interval is used as a threshold for the Geomorphic Change Detection showing more reliable results. However, caution should be taken when interpreting thresholded maps of changes and sediment budgets because some beach processes may be masked, especially on wide tidal beaches, by only keeping the most significant changes. The results of the shoreline mobility and Geomorphic Change Detection show a high variability in the beach responses between and within the three study sites, explained mainly by beach orientation and local factors. Despite variable site-specific mechanisms, the recovery processes redistribute the available sand more on the upper parts of the beach, producing significant deposition generally in the form of embryo dunes. The monitoring of the beach and dune systems with airborne LiDAR datasets reveals that the three study sites show diverse behaviours during the first period likely associated with storms, while the analysis show more homogenous beach responses during the second period likely associated with a recovery phase.

Tectonic Signals Deduced from Quantitative Analysis of Geomorphic Parameters in Bedrock Rivers and Structural Mapping: A case study from the Surai Khola Siwalik Section, Nepalese Himalaya

NASA Astrophysics Data System (ADS)

Bhattarai, I.; Gani, N. D.

2016-12-01

The Nepalese Himalaya is one of the most active regions within the Himalayan Mountain Belt, which is characterized by a thick succession of Siwalik sedimentary rocks deposited at its foreland basin. To date, much of the tectonic geomorphologic study in the Nepalese Siwalik is poorly understood, particularly in the Surai Khola section. Thus, the study of quantitative analysis of bedrock river parameters will provide crucial information regarding tectonic activities in the area. This study investigates geomorphic parameters of longitudinal river profiles from 54 watersheds within the Siwalik section of the Nepalese Himalaya. We extracted a total of 140 bedrock rivers from these watersheds using stream power-law function and 30-meter resolution ASTER DEM. In addition, we used 90-meter resolution SRTM DEM for structural mapping within the Surai Khola section. Our new results show presence of major and minor knickpoints that were classified on the basis of relief of the longitudinal profiles. We identified 180 major knickpoints out of 305 total knickpoints. Normalized steepness index (ksn) and concavity index values vary above and below these knicpoints. The ksn values range from 5.3 to 140.6 while concavity index of the streams in the study area ranges from as low as -12.1 to as high as 31.1. We also identified a total of 133 structural lineations that were mapped for the first time using various sun illumination angles and azimuths, and slope. Most of these structural lineations are likely faults that follow the similar east-west trends of the Main Frontal Thrust (MFT) Fault. The length of these faults ranges from 0.5 km to 8 km. We interpreted that a few measured knickpoints might be associated with our mapped mesoscale faults, while the majority of the knickpoints in the river profiles are locally adjusting to the MFT related uplift.

An exhaustive approach for identification of flood risk hotspots in data poor regions enforcing combined geomorphic and socio-economic indicators

NASA Astrophysics Data System (ADS)

Mohanty, M. P.; Karmakar, S.; Ghosh, S.

2017-12-01

Many countries across the Globe are victims of floods. To monitor them, various sophisticated algorithms and flood models are used by the scientific community. However, there still lies a gap to efficiently mapping flood risk. The limitations being: (i) scarcity of extensive data inputs required for precise flood modeling, (ii) fizzling performance of models in large and complex terrains (iii) high computational cost and time, and (iv) inexpertise in handling model simulations by civic bodies. These factors trigger the necessity of incorporating uncomplicated and inexpensive, yet precise approaches to identify areas at different levels of flood risk. The present study addresses this issue by utilizing various easily available, low cost data in a GIS environment for a large flood prone and data poor region. A set of geomorphic indicators of Digital Elevation Model (DEM) are analysed through linear binary classification, and are used to identify the flood hazard. The performance of these indicators is then investigated using receiver operating characteristics (ROC) curve, whereas the calibration and validation of the derived flood maps are accomplished through a comparison with dynamically coupled 1-D 2-D flood model outputs. A high degree of similarity on flood inundation proves the reliability of the proposed approach in identifying flood hazard. On the other hand, an extensive list of socio-economic indicators is selected to represent the flood vulnerability at a very finer forward sortation level using multivariate Data Envelopment Analysis (DEA). A set of bivariate flood risk maps is derived combining the flood hazard and socio-economic vulnerability maps. Given the acute problem of floods in developing countries, the proposed methodology which may be characterized by low computational cost, lesser data requirement and limited flood modeling complexity may facilitate local authorities and planners for deriving effective flood management strategies.

Rockfalls in the Duratón canyon, central Spain: Inventory and statistical analysis

NASA Astrophysics Data System (ADS)

Tanarro, Luis M.; Muñoz, Julio

2012-10-01

This paper presents an initial analysis of the rockfall processes affecting the walls of the canyon of the River Duratón. This 34 km long meandering canyon in the basin of the River Duero in central Spain (41°18' N, 3°45' W) has evolved in a large-scale outcrop of Late Cretaceous calcareous rocks (dolomite and limestone) deformed into a series of asymmetrical folds. Its vertical scarps range from 80 to 100 m; its width varies from 150 to 300 m; and its floor is between 30 and 50 m wide. The research consisted of drawing up an inventory of rockfalls from a field survey and mapping the fallen blocks deposited on the basal talus or on the canyon floor, which in turn allowed the original location of each block on the scarps to be identified and located on the orthophotos available. A Digital Elevation Model (DEM) was produced using a Geographic Information System (GIS) and maps made of the aspects and slopes. The aspect of each rockfall data point was determined, and this initial database was completed with other significant parameters (location on the valley side, relationship with the tectonic structure and relative age). An approximate delimitation was also produced of the potential rockfall source area, by reclassifying the slopes according to morphometric criteria. The result is a geomorphic rockfall inventory map, showing the distribution of the rockfalls and a basic statistical analysis to allow a preliminary evaluation of the rockfall characteristics in relation to both their topoclimatic location (aspect) and their structural location (with or counter to the dip of the strata) and to the current geomorphic dynamic through a study of recent scars on the scarps. Recent rockfalls have also been related to the meteorological conditions in which they occurred.

Controls on large landslide distribution and implications for the geomorphic evolution of the southern interior Columbia River basin

USGS Publications Warehouse

Safran, E.B.; Anderson, S.W.; Mills-Novoa, M.; House, P.K.; Ely, L.

2011-01-01

Large landslides (>0.1 km2) are important agents of geomorphic change. While most common in rugged mountain ranges, large landslides can also be widespread in relatively low-relief (several 100 m) terrain, where their distribution has been relatively little studied. A fuller understanding of the role of large landslides in landscape evolution requires addressing this gap, since the distribution of large landslides may affect broad regions through interactions with channel processes, and since the dominant controls on landslide distribution might be expected to vary with tectonic setting. We documented >400 landslides between 0.1 and ~40 km2 across ~140,000 km2 of eastern Oregon, in the semiarid, southern interior Columbia River basin. The mapped landslides cluster in a NW-SE-trending band that is 50-100 km wide. Landslides predominantly occur where even modest local relief (~100 m) exists near key contacts between weak sedimentary or volcaniclastic rock and coherent cap rock. Fault density exerts no control on landslide distribution, while ~10% of mapped landslides cluster within 3-10 km of mapped fold axes. Landslide occurrence is curtailed to the NE by thick packages of coherent basalt and to the SW by limited local relief. Our results suggest that future mass movements will localize in areas stratigraphically preconditioned for landsliding by a geologic history of fluviolacustrine and volcaniclastic sedimentation and episodic capping by coherent lava flows. In such areas, episodic landsliding may persist for hundreds of thousands of years or more, producing valley wall slopes of ~7??-13?? and impacting local channels with an evolving array of mass movement styles. ?? 2011 Geological Society of America.

Recognition of large scale deep-seated landslides in vegetated areas of Taiwan

NASA Astrophysics Data System (ADS)

Lin, C. W.; Tarolli, P.; Tseng, C. M.; Tseng, Y. H.

2012-04-01

In August 2009, Typhoon Morakot triggered thousands of landslides and debris flows, and according to government reports, 619 people were dead and 76 missing and the economic loss was estimated at hundreds million of USD. In particular, the large deep-seated landslides are critical and deserve attention, since they can be affected by a reactivation during intense events, that usually can evolve in destructive failures. These are also difficult to recognize in the field, especially under dense forest areas. A detailed and constantly updated inventory map of such phenomena, and the recognition of their topographic signatures really represents a key tool for landslide risk mitigation, and mapping. The aim of this work is to test the performance of a new developed method for the automatic extraction of geomorphic features related to landslide crowns developed by Tarolli et al. (2010), in support to field surveys in order to develop a detailed and accurate inventory map of such phenomena. The methodology is based on the detection of thresholds derived by the statistical analysis of variability of landform curvature from high resolution LiDAR derived topography. The analysis suggested that the method allowed a good performance in localization and extraction, respect to field analysis, of features related to deep-seated landslides. Thanks to LiDAR capabilty to detect the bare ground elevation data also in forested areas, it was possible to recognize in detail landslide features also in remote regions difficult to access. Reference Tarolli, P., Sofia, G., Dalla Fontana, G. (2010). Geomorphic features extraction from high-resolution topography: landslide crowns and bank erosion, Natural Hazards, doi:10.1007/s11069-010-9695-2

HYDROLOGIC AND GEOMORPHIC CONTROLS ON RIPARIAN ECOSYSTEMS IN THE GREAT BASIN OF CENTRAL NEVADA

EPA Science Inventory

Understanding surface and ground water flow system interactions is key to maintaining and restoring riparian and wet meadow ecosystems, especially in the Great Basin of central Nevada where they support the majority of the region's biodiversity. To better understand these intera...

Geomorphic Identification and Verification of Recent Sedimentation Patterns in the Woonasquatucket River, North Providence, Rhode Island

DTIC Science & Technology

2007-03-01

8 The Centre Cotton Manufacturing Company (1812).................................................................. 9...112 Data collection...sedimentation surface) derived from the CF:CS 210Pb model. Data are not available for vibracores CMS- SD-4210 and CMS-SD-4213 in 1938 and 1958 and

Quantifying uncertainty of measuring gully morphological evolution with close-range digital photogrammetry

USDA-ARS?s Scientific Manuscript database

Measurement of geomorphic change may be of interest to researchers and practitioners in a variety of fields including geology, geomorphology, hydrology, engineering, and soil science. Landscapes are often represented by digital elevation models. Surface models generated of the same landscape over a ...

Old River Control Complex Sedimentation Investigation

DTIC Science & Technology

2015-06-01

efforts to describe the shoaling processes and sediment transport in the two-river system. Geomorphic analysis The geomorphic assessment utilized...District, New Orleans. The investigation was conducted via a combination of field data collection and laboratory analysis, geomorphic assessments, and...6 Geomorphic analysis

Using soil properties as a tool to differentiate landslide generations and constrain their ages - Rogowiec landslide, Sudetes (SW Poland)

NASA Astrophysics Data System (ADS)

Kacprzak, Andrzej; Migoń, Piotr

2013-04-01

The Sudetes, at the border of Poland and the Czech Republic, are generally considered as a mountain range where landslides play a marginal geomorphic role. Only a few larger landslides have been recorded during historical times, mainly on steep valley sides undercut by rivers. Forested slopes, which dominate in the Sudetes, are usually inferred to be stable, except for near-surface bioturbation and localized accelerated surface erosion at sites subject to strong human impact. Large, apparently relict landslides in the Kamienne Mountains, Middle Sudetes, pose a considerable challenge to this view and two interpretations are possible. First, they may be indeed relict, pre-Holocene features that formed under different environmental conditions and have been completely stabilized since the origin. Second, they may be rare components of the contemporary (Holocene) geomorphic system but their frequency of occurrence is low and this is why none has been reported in written or oral records. If the second scenario captures the reality adequately, this would have significant implications for hazard and risk assessment. To address this issue, an extensive soil survey was carried out on the large landslide of Rogowiec, likely of complex flow nature as suggested by landform mapping. The rationale of the study involved an assumption that soil formation time in the area is limited to the Holocene, since harsh periglacial conditions typified the late Pleistocene. 15 soil pits were excavated within landslide terrain and on adjacent reference slopes which do not bear any evident traces of significant displacements. Despite the small area under investigation, the soil profiles are very diverse in terms of depth, horizonation, organic matter content, development of soil structure, as well as the content and lithology of coarse fragments. A great deal of this diversity can be explained by different duration of pedogenesis controlled by geomorphic processes. Very weakly developed soil profiles in the landslide body do not show evidence of protracted soil evolution under contemporary climate and hence, are interpreted as having been formed during a fraction of the Holocene. This implies a Holocene age of the landslide. In addition, an older shallow translational landslide has been recognized on the valley side, with the toe buried by the main Rogowiec landslide. The depletion area was identified through the occurrence of thin, truncated soils (compared to the neighbouring slopes). This and the occurrence of weakly horizonated and poorly structural soils in the landslide body itself suggest that this valley-side landslide is of the Holocene age too. Thus, soils proved a powerful tool to establish the relative chronology of landslides and give strong evidence of their Holocene age. Soil research is recommended as a part of landslide hazard and risk assessment for landslides of unknown age.

Surface slip and off-fault deformation patterns in the 2013 MW 7.7 Balochistan, Pakistan earthquake: Implications for controls on the distribution of near-surface coseismic slip

NASA Astrophysics Data System (ADS)

Zinke, Robert; Hollingsworth, James; Dolan, James F.

2014-12-01

Comparison of 398 fault offsets measured by visual analysis of WorldView high-resolution satellite imagery with deformation maps produced by COSI-Corr subpixel image correlation of Landsat-8 and SPOT5 imagery reveals significant complexity and distributed deformation along the 2013 Mw 7.7 Balochistan, Pakistan earthquake. Average slip along the main trace of the fault was 4.2 m, with local maximum offsets up to 11.4 m. Comparison of slip measured from offset geomorphic features, which record localized slip along the main strand of the fault, to the total displacement across the entire width of the surface deformation zone from COSI-Corr reveals ˜45% off-fault deformation. While previous studies have shown that the structural maturity of the fault exerts a primary control on the total percentage of off-fault surface deformation, large along-strike variations in the percentage of strain localization observed in the 2013 rupture imply the influence of important secondary controls. One such possible secondary control is the type of near-surface material through which the rupture propagated. We therefore compared the percentage off-fault deformation to the type of material (bedrock, old alluvium, and young alluvium) at the surface and the distance of the fault to the nearest bedrock outcrop (a proxy for sediment thickness along this hybrid strike slip/reverse slip fault). We find significantly more off-fault deformation in younger and/or thicker sediments. Accounting for and predicting such off-fault deformation patterns has important implications for the interpretation of geologic slip rates, especially for their use in probabilistic seismic hazard assessments, the behavior of near-surface materials during coseismic deformation, and the future development of microzonation protocols for the built environment.

Regional liquefaction hazard evaluation following the 2010-2011 Christchurch (New Zealand) earthquake sequence

NASA Astrophysics Data System (ADS)

Begg, John; Brackley, Hannah; Irwin, Marion; Grant, Helen; Berryman, Kelvin; Dellow, Grant; Scott, David; Jones, Katie; Barrell, David; Lee, Julie; Townsend, Dougal; Jacka, Mike; Harwood, Nick; McCahon, Ian; Christensen, Steve

2013-04-01

Following the damaging 4 Sept 2010 Mw7.1 Darfield Earthquake, the 22 Feb 2011 Christchurch Earthquake and subsequent damaging aftershocks, we completed a liquefaction hazard evaluation for c. 2700 km2 of the coastal Canterbury region. Its purpose was to distinguish at a regional scale areas of land that, in the event of strong ground shaking, may be susceptible to damaging liquefaction from areas where damaging liquefaction is unlikely. This information will be used by local government for defining liquefaction-related geotechnical investigation requirements for consent applications. Following a review of historic records of liquefaction and existing liquefaction assessment maps, we undertook comprehensive new work that included: a geologic context from existing geologic maps; geomorphic mapping using LiDAR and integrating existing soil map data; compilation of lithological data for the surficial 10 m from an extensive drillhole database; modelling of depth to unconfined groundwater from existing subsurface and surface water data. Integrating and honouring all these sources of information, we mapped areas underlain by materials susceptible to liquefaction (liquefaction-prone lithologies present, or likely, in the near-surface, with shallow unconfined groundwater) from areas unlikely to suffer widespread liquefaction damage. Comparison of this work with more detailed liquefaction susceptibility assessment based on closely spaced geotechnical probes in Christchurch City provides a level of confidence in these results. We tested our susceptibility map by assigning a matrix of liquefaction susceptibility rankings to lithologies recorded in drillhole logs and local groundwater depths, then applying peak ground accelerations for four earthquake scenarios from the regional probabilistic seismic hazard model (25 year return = 0.13g; 100 year return = 0.22g; 500 year return = 0.38g and 2500 year return = 0.6g). Our mapped boundary between liquefaction-prone areas and areas unlikely to sustain heavy damage proved sound. In addition, we compared mapped liquefaction extents (derived from post-earthquake aerial photographs) from the 4 Sept 2010 Mw7.1 and 22 Feb 2011 Mw6.2 earthquakes with our liquefaction susceptibility map. The overall area of liquefaction for these two earthquakes was similar, and statistics show that for the first (large regional) earthquake, c. 93% of mapped liquefaction fell within the liquefaction-prone area, and for the second (local, high peak ground acceleration) earthquake, almost 99% fell within the liquefaction-prone area. We conclude that basic geological and groundwater data when coupled with LiDAR data can usefully delineate areas susceptible to liquefaction from those unlikely to suffer damaging liquefaction. We believe that these techniques can be used successfully in many other cities around the world.

Colorado River Vegetation, and Climate: Five Decades of Spatio-Temporal Dynamics in the Grand Canyon in Response to River Regulation

NASA Astrophysics Data System (ADS)

Ralston, B. E.; Sankey, J. B.

2013-12-01

Recent analysis of remotely sensed imagery of 400 km of the Colorado River confirms a net increase in vegetated area has occurred since the completion of Glen Canyon Dam in 1963. The rates and magnitude of vegetation change appear to be river stage-dependent. Riparian vegetation expansion on geomorphic surfaces at lower elevations relative to the river was greater for decades with lower peak and average discharges. Vegetation change at higher elevation relative to the river indicate that increases and decreases in vegetated area reflect regional precipitation patterns, and respectively coincide with regionally significant wet and dry periods that include the current early 21st century drought. The objective of this work was to examine the temporal persistence, and changes, in the spatial distribution of riparian vegetation relative to geomorphic characteristics of the Colorado River in Grand Canyon, dam and reservoir management, and regional climate over the 5-decade period from the mid-1960s to present. We employed archived riparian vegetation classifications that used aerial imagery from 1965, 1973, 1984, 1992, 2002, and 2009 coupled with flow regime data that is primarily related to operations of Glen Canyon Dam, field-measured rating relations, predictions of rating relations based on 1-D modeling, and detailed, geomorphic field mapping. Documentation of the effects of river regulation on riparian habitats in the SW USA has traditionally been limited to either small segments of river channels (e.g., 0.1-10km), or focused on specific plant species. The smaller geographic scale approach evaluates local hydrology, river channel changes, and serial recruitment events of riparian plants. The species-specific plant response informs larger scale patterns of riparian plant distributions across the landscape, but is less sensitive to differences of climate and hydrology among rivers. Our study is unique in that it employs datasets that allow both large-scale change detection and local-scale analysis to address questions about transferability of local-scale plant response to the larger river system. Furthermore, we assess the independent and interacting effects of river regulation and regional climate on plant response. Our results show promise for improved understanding of the interplay of river regulation and climate effects for riparian vegetation at a local and river-wide scale in this highly modified river system.

Reconnaissance geologic mapping of a portion of the rain‐forest‐covered Guiana Shield, Northwestern Brazil, using SIR-B and digital aeromagnetic data

USGS Publications Warehouse

Pellon de Miranda, Fernando; McCafferty, Anne E.; Taranik, James V.

1994-01-01

This paper documents the result of an integrated analysis of spaceborne radar (SIR-B) and digital aeromagnetic data carried out in the heavily forested Guiana Shield. The objective of the research is to interpret the geophysical data base to its limit to produce a reconnaissance geologic map as an aid to ground work planning in a worst‐case setting. Linear geomorphic features were identified based on the interpretation of the SIR-B image. Digital manipulation of aeromagnetic data allowed the development of a color‐shaded relief map of reduced‐to‐pole magnetic anomalies, a terrace‐magnetization map, and a map showing the location of maximum values of the horizontal component of the pseudogravity gradient (magnetization boundary lines). The resultant end product was a reconnaissance geologic map where broad terrane categories were delineated and geologic faults with both topographic and magnetic expression were defined. The availability of global spaceborne radar coverage in the 1990s and the large number of existing digital aeromagnetic surveys in northwestern Brazil indicate that this approach can be potentially useful for reconnaissance geologic mapping elsewhere in the Guiana Shield.

Mapping seabed geomorphology in the Inner Hebrides, Scotland; Bathymetric records of ice streaming and retreat

NASA Astrophysics Data System (ADS)

Dove, Dayton; Finlayson, Andrew; Bradwell, Tom; Arosio, Riccardo; Howe, John

2014-05-01

Approximately 7,000 km² of new bathymetry have been stitched together with onshore airborne radar data, both gridded at 5m resolution, to map and describe the submarine glacial landscape of the Inner Hebrides sector of the former British-Irish Ice Sheet (BIIS). As part of the MAREMAP Project (http://www.maremap.ac.uk), and to build on previous work (Howe et al., 2012), we are using recently acquired swath bathymetry data, collected primarily by the UKHO Civil Hydrography Programme, to characterise the geomorphology, sea-bed sediments, and bedrock geology of the Inner Hebrides region. Mapping has revealed an extensive array of well-preserved glacigenic landforms on the seabed associated with key stages of ice flow and retreat of the BIIS following the Last Glacial Maximum. On multiple submarine rock platforms and within overdeepened troughs, diverse assemblages of glacially streamlined landforms are present, forming a geomorphic continuum between rock drumlins and mega-flutes. Superimposed streamlined bedforms indicate different phases of fast flow at the ice sheet bed, and the convergence of flow sets suggest that ice sheet flow was organised into faster flowing topographically controlled corridors. Across the region, the streamlined landforms occur within a geographically controlled zone, semi-independent of the underlying geology. This is consistent with the onset zone of the Hebrides Ice Stream, as previously postulated (Howe et al., 2012). Submarine moraine ridges are observed widely across the survey area: within sea lochs, atop rock platforms and superimposed on glacially streamlined bedforms, as well as pinned to topographic highs (i.e. islands). Some retreat patterns reveal clear glacial recession towards respective catchments, while others are more ambiguous and are the focus of ongoing work. The bathymetry data notably reveal more geomorphic evidence of glaciation than adjacent land records, thus providing the opportunity to reassess onshore mapping where clear offshore examples may provide insights into poorly understood terrestrial geological and geomorphological features. And importantly, these new data provide the opportunity to greatly improve offshore geology maps of the region, which are in increasing demand by governmental, commercial, and conservation groups.

Uplifted Terraces along the Southeastern Coast of Bangladesh Reveal the Extent of 1762 Earthquake Surface Deformation and Potentially Document Prior Earthquakes

NASA Astrophysics Data System (ADS)

Mondal, D. R.; McHugh, C.; Steckler, M. S.; Seeber, L.; Akhter, S. H.; Mustaque, S.; Knappett, P. S.

2016-12-01

To better understand geohazards for Bangladesh, the surface expression of the 1762 earthquake and previous earthquakes, we surveyed the coast of Teknaf for evidence of uplift with high precision NetR9, RTX GPS. Previous studies by Aung et al. (2006; 2008) and Wang et al. (2013) documented uplifted terraces along the west coast of Myanmar and linked the youngest terrace to the 1762 Arakan earthquake. Previous studies by Mondal et al. (2015) documented 2.5 m uplifted microatoll corals in the Saint Martin anticline, 10 km southwest from the Teknaf coastline, and linked their uplift by U/Th ages to the 1762 earthquake. Along the southeast Bangladesh coastline, we mapped three geomorphic terraces for 70 km from Teknaf to Cox's Bazar. While GPS measured the location and elevation, an optical level (Theodolite) was used to survey across the different terraces from the beach to the Teknaf anticline foothills. The terraces were also characterized by slope analysis using 30 m SRTM DEM to understand the relation between the terrace geomorphology and potential influence from slope aprons derived from the erosion of the anticline. Our results show that the elevation of three terraces is consistent along the coast, and that terrace elevation ranges from 2-5 m, 5 -7 m and 11-13 m for the youngest, intermediate and oldest terrace, respectively. The youngest terrace, previously dated by McHugh et al. (2015) using C-14 from marine shells obtained from the terrace top, is linked to uplift from the 1762 earthquake. Marine fossils are present in the oldest terrace, and we will present the C-14 age results. Results also suggest that the higher terrace is not prominent in those locations where the slope of the anticline aprons is very high, and they are in a close proximity to each other. The present geomorphic evidence suggests that these terraces were uplifted by three paleoearthquakes, and C-14 ages will provide timing for the uplift. Evidence of terrace uplift derived from our GPS survey extends the 1762 surface deformation and megathrust rupture for at least 550 km along the Arakan segment of the Sunda subduction boundary.

Paleo ice-cap surfaces and extents

NASA Astrophysics Data System (ADS)

Gillespie, A.; Pieri, D.

2008-12-01

The distribution, equilibrium-line altitude (ELA) and timing of Pleistocene alpine glaciers are used to constrain paleoclimatic reconstructions. Attention has largely focused on the geomorphic evidence for the former presence of simple valley glaciers; paleo alpine ice caps and their outlet glaciers have proven to be more problematical. This is especially so in the remote continental interior of Asia, where the research invested in the Alps or Rocky Mountains has yet to be duplicated. Even the putative existence and size of paleo ice caps in Tibet and the Kyrgyz Tien Shan is controversial. Remote sensing offers the opportunity to assess vast tracts of land quickly, with images and co-registered digital elevation models (DEMs) offering the most information for studies of paleoglaciers. We pose several questions: (1) With what confidence can nunataks be identified remotely? (2) What insights do their physiographic characteristics offer? (3) What characteristics of the bed of a paleo ice cap can be used to identify its former presence remotely? and (4) Can the geomorphic signatures of the edges of paleo ice caps be recognized and mapped? Reconstruction of the top surface of a paleo ice cap depends on the recognition of nunataks, typically rougher at 1 m to 100 m scales than their surroundings. Nunataks in southern Siberia are commonly notched by multiple sub- horizontal bedrock terraces. These step terraces appear to originate from freeze-thaw action on the rock-ice interface during periods of stability, and presence of multiple terraces suggests stepwise lowering of ice surfaces during deglaciation. An older generation of step-terraced nunataks, distinguished by degraded and eroded terraces, delineates a larger paleo ice cap in the Sayan Range (Siberian - Mongolian border) that significantly pre-dates the last glacial maximum (LGM). Large ice caps can experience pressure melting at their base and can manifest ice streams within the ice cap. Valleys left behind differ from fluvial valleys in their width/depth profiles: the channels maintain width but get shallower near their sources. Link junction angle distributions within superimposed drainage networks are broader and distinct from those of evolved fluvial networks, and their character and statistics can be used to identify the perimeters of large paleo ice caps. (This work was carried out in part at the Jet Propulsion Laboratory of the California Institute of Technology under contract to NASA.)

Characterization of geomorphic units in the alluvial valleys and channels of Gulf Coastal Plain rivers in Texas, with examples from the Brazos, Sabine, and Trinity Rivers, 2010

USGS Publications Warehouse

Coffman, David K.; Malstaff, Greg; Heitmuller, Franklin T.

2011-01-01

The U.S. Geological Survey, in cooperation with the Texas Water Development Board, described and characterized examples of geomorphic units within the channels and alluvial valleys of Texas Gulf Coastal Plain rivers using a geomorphic unit classification scale that differentiates geomorphic units on the basis of their location either outside or inside the river channel. The geomorphic properties of a river system determine the distribution and type of potential habitat both within and adjacent to the channel. This report characterizes the geomorphic units contained in the river channels and alluvial valleys of Texas Gulf Coastal Plain rivers in the context of the River Styles framework. This report is intended to help Texas Instream Flow Program practitioners, river managers, ecologists and biologists, and others interested in the geomorphology and the physical processes of the rivers of the Texas Gulf Coastal Plain (1) gain insights into how geomorphic units develop and adjust spatially and temporally, and (2) be able to recognize common geomorphic units from the examples cataloged in this report. Recent aerial imagery (high-resolution digital orthoimagery) collected in 2008 and 2009 were inspected by using geographic information system software to identify representative examples of the types of geomorphic units that occurred in the study area. Geomorphic units outside the channels of Texas Gulf Coastal Plain rivers are called \\"valley geomorphic units\\" in this report. Valley geomorphic units for the Texas Gulf Coastal Plain rivers described in this report are terraces, flood plains, crevasses and crevasse splays, flood-plain depressions, tie channels, tributaries, paleochannels, anabranches, distributaries, natural levees, neck cutoffs, oxbow lakes, and constructed channels. Channel geomorphic units occur in the river channel and are subject to frequent stresses associated with flowing water and sediment transport; they adjust (change) relatively quickly in response to short-term variations in flow. Channel geomorphic units described in this report are channel banks, benches and ledges, bank failures, point bars, cross-bar channels, channel bars, exposed bedrock, pools, runs, and crossovers.

Assessing the Geomorphic Evolution and Hydrographic Changes Induced by Winter Storms along the Louisiana Coast

NASA Technical Reports Server (NTRS)

Menzel, W. Paul; Moeller, Christopher, C; Huh, Oscar K.; Roberts, Harry H.

1998-01-01

The influence that cold front passages have on Louisiana coastal environments, including land loss and land building processes, has been the primary topic of this multidisciplinary research. This research has combined meteorological, remote sensing, and coastal expertise from the University of Wisconsin (UW) and Louisiana State University (LSU). Analyzed data sets include remotely sensed radiometric data (AVHRR on NOAA-12,13,14, Multispectral Atmospheric Mapping Sensor (MAMS) and MODIS Airborne Simulator (MAS) on NASA ER-2), U.S. Army Corps of Engineers (USACE) water level data, water quality data from the Coastal Studies Institute (CSI) at LSU, USACE river discharge data, National Weather Service (NWS) and CSI wind in sitzi measurements, geomorphic measurements from aerial photography (NASA ER-2 and Learjet), and CSI ground based sediment burial pipes (for monitoring topographic change along the Louisiana coast) and sediment cores. The work reported here-in is a continuation of an initial investigation into coastal Louisiana landform modification by cold front systems. That initial effort demonstrated the importance of cold front winds in the Atchafalaya Bay sediment plume distribution (Moeller et al.), documented the sediment transport and deposition process of the western Louisiana coast (Huh et al.) and developed tools (e.g. water types identification, suspended solids estimation) from multispectral radiometric data for application to the current study. This study has extended that work, developing a Geomorphic Impact Index (GI(sup 2)) for relating atmospheric forcing to coastal response and new tools to measure water motion and sediment transport.

PHOSPHORUS SORPTION DYNAMICS IN SOILS AND COUPLING WITH SURFACE AND PORE WATER IN RIVERINE WETLANDS

EPA Science Inventory

Adsorption to soils is one of the dominant mechanisms of P storage in wetlands. We examined P sorption dynamics in soils collected at 12 sample points with diverse hydrology, geomorphic position, mineralogy, and plant communities in two riverine wetlands in northern Minnesota and...

Transient Fluvial Response to Alpine Deglaciation, Mount Rainier, WA: Geomorphic Process Domains and Proglacial Flux Controls on Channel Evolution.

NASA Astrophysics Data System (ADS)

Beyeler, J. D.; Montgomery, D.; Kennard, P. M.

2016-12-01

Downwasting of all glaciers on the flanks of Mount Rainier, WA, in recent decades has debuttressed Little Ice Age glaciogenic sediments driving proglacial responses to regionally warming climate. Rivers draining the deglaciating edifice are responding to paraglacial sedimentation processes through transient storage of retreat-liberated sediments in aggrading (e.g., >5m) fluvial networks with widening channel corridors (i.e., 50-150%) post-LIA (ca., 1880-1910 locally). We hypothesize that the downstream transmission of proglacial fluxes (i.e., sediment and water) through deglaciating alpine terrain is a two-step geomorphic process. The ice-proximal portion of the proglacial system is dominated by the delivery of high sediment-to-water ratio flows (i.e., hyperconcentrated and debris slurries) and sediment retention by in-channel accumulation (e.g., confined debris fans within channel margins of valley segments) exacerbated by recruitment and accumulation of large wood (e.g., late seral stage conifers), whereas ice-distal fluvial reworking of transient sediment accumulations generates downstream aggradation. Historical Carbon River observations show restricted ice-proximal proglacial aggradation until a mainstem avulsion in 2009 initiated incision into sediment accumulations formed in recent decades, which is translating into aggradation farther down the network. Surficial morphology mapped with GPS, exposed subsurface sedimentology, and preliminary dating of buried trees suggest a transitional geomorphic process zone has persisted along the proglacial Carbon River through recent centuries and prior to the ultimate LIA glaciation. Structure-from-motion DEM differencing through the 2016 water year shows discrete zones of proglacial evolution through channel-spanning bed aggradation forced by interactions between large wood and sediment-rich flows that transition to fluvial process dominance as sediment is transported downstream. Long-term DEM differencing suggests these are persistent geomorphic processes as rivers respond to alpine deglaciation. This process-based study implies downstream river flooding in deglaciating alpine terrain globally is driven by glaciogenic sediment release and downstream channel aggradation irrespective of changes in discharge.

Geomorphic responses of lower Bega River to catchment disturbance, 1851?1926

NASA Astrophysics Data System (ADS)

Brooks, Andrew P.; Brierley, Gary J.

1997-03-01

Prior to significant European settlement of the area in the 1850s, lower Bega River on the South Coast of NSW had a narrow, relatively deep channel lined by river oaks. The river had a suspended or mixed load, with platypus habitat available in pools. Banks were fine-grained and relatively cohesive (silts and clays), as was the floodplain, which graded to a series of valley-marginal swamps and lakes. Extensive evidence from maps and portion plans, archival photographs, bridge surveys, and anecdotal sources, complemented by field analysis of floodplain sedimentology (including radiocarbon-dated samples) and vegetation remnants are used to document the dramatic metamorphosis in the character and behaviour of lower Bega River in the latter half of the nineteenth century. By 1926 the channel had widened extensively (up to 340%) and shallowed in association with bed aggradation by coarse sandy bedload. Floodplain accretion was dominated by fine to medium sands, with some coarse sand splays. In contrast with most other studies of channel metamorphosis in Australia, which have emphasised river responses to climatically-induced flood histories, relegating human impacts to a secondary role, the profound changes to the geomorphic condition and behaviour of Bega River reflect indirect human disturbance of Bega catchment, and direct but non point source disturbance to the channel. Extensive clearance of catchment, floodplain, and channel-marginal vegetation occurred within a few decades of European settlement, altering the hydrologic and sediment regime of the river, and transforming the geomorphic effectiveness of floods. Although this study is situated in a relatively sensitive, granitic catchment, catchment clearance is likely to have induced equally significant responses in many other river systems in eastern Australia. In some instances the diffuse aspects of human disturbance on landscapes induce impacts on river character that are just as profound as major direct disturbances of river channels. This may have profound implications in understanding, and hence managing, the geomorphic consequences of river behaviour in Australia and elsewhere.

The Gale Crater Mound in a Regional Geologic Setting

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Korn, L. K.

2012-01-01

The Mars Science Laboratory Rover Curiosity is commencing a two-year investigation of Gale crater and Mt. Sharp, the crater s prominent central mound. Gale is a 155 km, late Noachian / early Hesperian impact crater located near the dichotomy boundary separating the southern highlands from the northern plains. The central mound is composed of layered sedimentary rock, with upper and lower mound units separated by a prominent erosional unconformity (Milliken et al., 2010). The lower mound is of particular interest, as it contains secondary minerals indicative of a striking shift from water-rich to water-poor conditions on early Mars. A key unknown in the history of Gale is the relationship between the sedimentary units in the mound and sedimentary sequences in the surrounding region. We employed orbital remote sensing data to determine if areas within a 1,000 km radius of Gale match the characteristics of sedimentary units in Mt. Sharp. Regions of interest were defined based on: the mound s inferred age (late Noachian to early Hesperian), altitude range (-4,600 m to +400 m), and THEMIS nighttime brightness (a proxy for thermal inertia). This combination of characteristics is matched by two extensive units, the late Noachian subdued cratered unit Npl2 and Noachian / Hesperian undivided material HNu (Greeley and Guest, 1987), located along the dichotomy. Geomorphic units have been mapped within the Gale mound by Thomson et al. (2011) based on albedo, layering and erosional characteristics. Using orbital CTX, MOC and HiRISE images we examined all areas within our regions of interest for analogous geomorphic units in the same altitude ranges as the corresponding units in Mt. Sharp. The most convincing geomorphic analogs to lower mound units, dominated by fine-scale layering and prominent yardangs, were located approximately 200 km northeast and southeast of Gale in late Noachian unit Npl2. The most convincing geomorphic analogs to upper mound layered units are located 250 900 km northwest of Gale in unit HNu, estimated to span the Noachian / Hesperian boundary.

Episodes of fluvial and volcanic activity in Mangala Valles, Mars.

PubMed

Keske, Amber L; Hamilton, Christopher W; McEwen, Alfred S; Daubar, Ingrid J

2015-01-01

A new mapping-based study of the 900-km-long Mangala Valles outflow system was motivated by the availability of new high-resolution images and continued debates about the roles of water and lava in outflow channels on Mars. This study uses photogeologic analysis, geomorphic surface mapping, cratering statistics, and relative stratigraphy. Results show that Mangala Valles underwent at least two episodes of fluvial activity and at least three episodes of volcanic activity during the Late Amazonian. The occurrence of scoured bedrock at the base of the mapped stratigraphy, in addition to evidence provided by crater retention ages, suggests that fluvial activity preceded the deposition of two of the volcanic units. Crater counts performed at 30 locations throughout the area have allowed us to construct the following timeline: (1) formation of Noachian Highlands and possible initial flooding event(s) before ~1 Ga, (2) emplacement of Tharsis lava flows in the valley from ~700 to 1000 Ma, (3) a megaflooding event at ~700-800 Ma sourced from Mangala Fossa, (4) valley fill by a sequence of lava flows sourced from Mangala Fossa ~400-500 Ma, (5) another megaflooding event from ~400 Ma, (6) a final phase of volcanism sourced from Mangala Fossa ~300-350 Ma, and (7) emplacement of eolian sedimentary deposits in the northern portion of the valley ~300 Ma. These results are consistent with alternating episodes of aqueous flooding and volcanism in the valles. This pattern of geologic activity is similar to that of other outflow systems, such as Kasei Valles, suggesting that there is a recurring, and perhaps coupled, nature of these processes on Mars.

Geomorphic influences of the Little Ice Age glacial advance on selected hillslope systems in Nordfjord, Western Norway (Erdalen and Bødalen valleys)

NASA Astrophysics Data System (ADS)

Laute, Katja; Beylich, Achim A.

2010-05-01

Hillslopes in glacially formed landscapes are typically characterized by talus cones developed beneath free rock faces. Studying hillslopes as sedimentary source, storage and transfer zones as well as surface processes acting on hillslopes since the end of the deglaciation is of importance in order to gain a better understanding of the complex sedimentary source-to-sink fluxes in cold climate environments. Hillslopes function as a key component within the geomorphic process response system. Large areas of the Norwegian fjord landscapes are covered by hillslopes and are characterized by the influences of the glacial inheritance. This PhD project is part of the NFR funded SedyMONT-Norway project within the ESF TOPO-EUROPE SedyMONT (Timescales of sediment dynamics, climate and topographic change in mountain landscapes) programme. The focus of this study is on geomorphic influences of the Little Ice Age glacial advance on postglacial hillslope systems in four distinct headwater areas of the Erdalen and Bødalen valleys in the Nordfjord valley-fjord system (inner Nordfjord, Western Norway). Both valleys can be described as steep, U-shaped and glacier-fed, subarctic tributary valleys. Approximately 14% of the 49 km2 large headwater areas of Erdalen are occupied by hillslope deposits and 41% by rock surfaces; in Bødalen hillslope deposits occupy 12% and rock surfaces occupy 38% of the 42 km2 large headwater areas. The main aims of this study are (i) to analyze and compare the morphometric characteristics as well as the composition of hillslope systems inside and outside of the Little Ice Age glacial limit, (ii) to detect possible changes within the mass balances of these hillslope systems, (iii) to identify the type and intensity of currently acting hillslope processes as well as (iv) to determine possible sediment sources and delivery pathways within the headwater areas of the catchments. The process-based approach includes orthophoto- and topographical map interpretation, hillslope profile surveying, photo monitoring, geomorphological mapping as well as GIS and DEM computing. Two appropriate hillslope test sites within each headwater area are selected in order to follow the main aims of this study. The designed monitoring instrumentation of the slope test sites includes nets for collecting freshly accumulated rockfall debris, stone tracer lines for measuring surface movements, wooden sticks for monitoring of slow surface creep movements and peg lines for depth-integrated measurements of slow mass movements. In addition, remote site cameras for monitoring rapid mass movement events (avalanches, slush- and debris flows) and slope wash traps for analyzing slope wash denudation are installed and measurements of solute concentrations at small hillslope drainage creeks for investigating the role of chemical denudation are conducted. Measurements of morphometric characteristics and longitudinal profiles along the main axis of the talus cones are carried out at each test site. The manually obtained longitudinal profile data are combined with data derived from a DEM in order to generate complete longitudinal hillslope profiles reaching from the apex until the slope foot. Preliminary results show a steepening trend of the talus cones located inside the Little Ice Age glacier limit which is due to erosion during the Little Ice Age glacial advance. In addition, some of these talus cones are characterized by a recognizable more complex talus cone morphometry and composition, resulting from implementation of Little Ice Age glacier side moraines. The combination of (i) steepened talus cones and (ii) complex composition seems to increase currently acting hillslope processes which leads to a higher sediment delivery from these slopes as compared to hillslopes outside the Little Ice Age glacier limit. The implementation of moraine material but also the increased intensity of denudative processes has a recognizable influence on the mass balance of the hillslope systems inside the Little Ice Age glacier limit. Research on the complex development of hillslope systems from a postglacial to contemporary time perspective in combination with analyses of contemporary sedimentary fluxes contributes to a better understanding of hillslopes acting as source, storage and transfer zones in cold climate environments (paraglacial systems).

Episodic Aggradation and Asynchronous Incision of River Terraces in the Kyrgyz Tien Shan

NASA Astrophysics Data System (ADS)

Burgette, R. J.; Weldon, R. J.; Abdkrakhmatov, K. Y.; Ormukov, C.

2006-12-01

Sequences of terraces and alluvial fans with characteristic geomorphic expression lie above or at the mouth of rivers in all of the major basins in the Tien Shan mountains of Kyrgyzstan. The similarity of terraces and fans in different drainage basins, despite being bounded by faults of varying activity and style, has been used to argue for synchronous regional climatic variations controlling the timing of aggradation and incision. Our emerging set of radiocarbon dates (currently 24) from terrace deposits and overlying sediments suggest that despite the general regional synchroneity of a late Pleistocene terrace-forming event, deep incision below broad aggradational surfaces may be locally controlled and occurred over time spans up to 30 k.y. The most prominent intra-canyon terrace is known as QIII(2) in the characteristic sequence of Tien Shan terraces. QIII(2) is a fill terrace everywhere except for the hanging walls of the most active thrust faults in the Tien Shan, where it has a strath terrace morphology. In many places the base of the QIII(2) fill is not visible even at the level of the modern river. Five dates in the fill from the Ak-Terek and Tong Rivers in the Issyk-Kul basin and Kajerty River in the Naryn basin are all >40 Ka, and may be beyond the limit of radiocarbon. The Issyk-Kul basin is occupied by a large lake, which provides additional dating possibilities, while potentially complicating the geomorphic system. In Issyk-Kul dates from sediment overlying the QIII(2) gravel in thick colluvial wedges far from the edge of the riser to lower terraces along the Ak-Terek and Tamga rivers show that at least the highest level of the fill was abandoned by 33-30 Ka. However, the downstream reaches of Issyk- Kul rivers' QIII(2) surfaces clearly remained active through a high stand of the lake that persisted from 38 to 20 Ka. Remnants of terraces with steeper gradients that merge upstream with surfaces inset only a few m into the main QIII(2) post-date the high stand and are locally preserved at the mouths of some rivers. To the west of Issyk-Kul, abandonment of the QIII(2) surface appears to have occurred at approximately 13 Ka in three basins of central Kyrgyzstan (Thompson et al., 2002). Taken together, these data show that QIII(2) aggradation was complete before 33 Ka and possibly as early as 40 Ka. Most rivers stayed at the level of the top of the fill with minor aggradation or incision for the next 13 to 25 k.y. Such long-lived stability results in a landscape where late Pleistocene surfaces that are at almost indistinguishable levels may vary in age by a factor >2. Similarly, ages of deposits in such fill terraces may be much older than the surfaces cut into them. While it is not yet clear over what region our results may apply, our observations suggest that the "same" geomorphic surface may be abandoned over a wide range of time and the upper few meters of gravel may be quite different in age than the bulk of the fill that forms the geomorphic feature. How this will affect slip rate estimates in central Asia is yet to be determined, but our observations motivate caution in assuming synchroneity of fills and their incision or synchroneity of similar- looking geomorphic features. Calculating accurate slip rates requires that one understands well the relationship between the feature where it is offset and where it is dated, particularly for relatively young terraces that do not average across many aggradation/incision cycles.

Geomorphic Evidence for Martian Ground Ice and Climate Change

NASA Technical Reports Server (NTRS)

Kanner, L. C.; Allen, C. C.; Bell, M. S.

2004-01-01

Recent results from gamma-ray and neutron spectrometers on Mars Odyssey indicate the presence of a hydrogen-rich layer tens of centimeters thick in the uppermost meter in high latitudes (greater than 60) on Mars. This hydrogen-rich layer correlates to regions of ice stability. Thus, the subsurface hydrogen is thought to be water ice constituting 35 plus or minus 15% by weight near the north and south polar regions. We refine the location of subsurface ice deposits at a less than km scale by combining existing spectroscopy data with surface features indicative of subsurface ice. A positive correlation between spectroscopy data and geomorphic ice indicators has been previously suggested for high latitudes. Here we expand the comparative study to northern mid latitudes (30 degrees N- 65 degrees N).

Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California

USGS Publications Warehouse

Reheis, Marith C.; Redwine, Joanna R.; Wan, Elmira; McGeehin, John P.; VanSistine, D. Paco

2014-01-01

Pluvial Lake Manix and its surrounding drainage basin, in the central Mojave Desert of California, has been a focus of paleoclimate, surficial processes, and neotectonic studies by the U.S. Geological Survey (USGS) since about 2004. The USGS initiated studies of Lake Manix deposits to improve understanding of the paleoclimatic record and the shifts in atmospheric circulation that controlled precipitation in the Mojave Desert. Until approximately 25,000 years ago, Lake Manix was the terminus of the Mojave River, which drains northeasterly from the San Bernardino Mountains; the river currently terminates in the Soda Lake and Silver Lake playas. Pleistocene Lake Manix occupied several subbasins at its maximum extent. This map focuses on the extensive exposures created by incision of the Mojave River and its tributaries into the interbedded lacustrine and alluvial deposits within the central (Cady) and northeastern (Afton) subbasins of Lake Manix, and extends from the head of Afton Canyon to Manix Wash. The map illuminates the geomorphic development and depositional history of the lake and alluvial fans within the active tectonic setting of the eastern California shear zone, especially interactions with the left-lateral Manix fault. Lake Manix left an extraordinarily detailed but complex record of numerous transgressive-regressive sequences separated by desiccation and deposition of fan, eolian, and fluvial deposits, and punctuated by tectonic movements and a catastrophic flood that reconfigured the lake basin. Through careful observation of the intercalated lacustrine and fan sequences and by determining the precise elevations of unit contacts, this record was decoded to understand the response of the lake and river system to the interplay of climatic, geomorphic, and tectonic forces. These deposits are exposed in steep badland topography. Mapping was carried out mostly at scales of 1:12,000, although the map is presented at 1:24,000 scale, and employs custom unit nomenclature, with multiple subdivided lacustrine and alluvial fan units. In addition, many important units are very thin and cannot be mapped separately, or are covered by thin eolian sand, so these are commonly portrayed as stacks of units or combined units. These details are more accurately portrayed in the measured sections that accompany the map. Altitudes of many contacts were obtained using differentially corrected Global Positioning System (GPS) or, in some cases, lidar (light detection and ranging) data.

Resurfacing history of the northern plains of Mars based on geologic mapping of Mars Global Surveyor data

USGS Publications Warehouse

Tanaka, K.L.; Skinner, J.A.; Hare, T.M.; Joyal, T.; Wenker, A.

2003-01-01

Geologic mapping of the northern plains of Mars, based on Mars Orbiter Laser Altimeter topography and Viking and Mars Orbiter Camera images, reveals new insights into geologic processes and events in this region during the Hesperian and Amazonian Periods. We propose four successive stages of lowland resurfacing likely related to the activity of near-surface volatiles commencing at the highland-lowland boundary (HLB) and progressing to lower topographic levels as follows (highest elevations indicated): Stage 1, upper boundary plains, Early Hesperian, <-2.0 to -2.9 km; Stage 2, lower boundary plains and outflow channel dissection, Late Hesperian, <-2.7 to -4.0 km; Stage 3, Vastitas Borealis Formation (VBF) surface, Late Hesperian to Early Amazonian, <-3.1 to -4.1 km; and Stage 4, local chaos zones, Early Amazonian, <-3.8 to -5.0 km. At Acidalia Mensa, Stage 2 and 3 levels may be lower (<-4.4 and -4.8 km, respectively). Contractional ridges form the dominant structure in the plains and developed from near the end of the Early Hesperian to the Early Amazonian. Geomorphic evidence for a northern-plains-filling ocean during Stage 2 is absent because one did not form or its evidence was destroyed by Stage 3 resurfacing. Remnants of possible Amazonian dust mantles occur on top of the VBF. The north polar layered deposits appear to be made up of an up to kilometer-thick lower sequence of sandy layers Early to Middle Amazonian in age overlain by Late Amazonian ice-rich dust layers; both units appear to have outliers, suggesting that they once were more extensive.

Analysis of radar images of the active volcanic zone at Krafla, Iceland: The effects of look azimuth biasing

NASA Technical Reports Server (NTRS)

Garvin, J. B.; Williams, R. S., Jr.

1989-01-01

The geomorphic expression of Mid-Ocean-Ridge (MOR) volcanism in a subaerial setting occurs uniquely on Earth in Iceland, and the most recent MOR eruptive activity has been concentrated in the Northeastern Volcanic Zone in an area known as Krafla. Within the Krafla region are many of the key morphologic elements of MOR-related basaltic volcanism, as well as volcanic explosion craters, subglacial lava shields, tectonic fissure swarms known as gjar, and basaltic-andesite flows with well developed ogives (pressure-ridges). The objective was to quantify the degree to which the basic volcanic and structural features can be mapped from directional SAR imagery as a function of the look azimuth. To accomplish this, the current expression of volcanic and tectonic constructs was independently mapped within the Krafla region on the E, W, and N-looking SAR images, as well as from SPOT Panchromatic imagery acquired in 1987. The initial observations of the E, W, and N images indicates that fresh a'a lava surfaces are extremely radar bright (rough at 3 cm to meter scales) independent of look direction; this suggests that these flows do not have strong flow direction related structures at meter and cm scales, which is consistent with typical Icelandic a'a lava surfaces in general. The basic impression from a preliminary analysis of the effects of look azimuth biasing on interpretation of the geology of an active MOR volcanic zone is that up to 30 percent of the diagnostic features can be missed at any given look direction, but that having two orthogonal look direction images is probably sufficient to prevent gross misinterpretation.

Science synergism study for EOS on evolution of desert surfaces

NASA Technical Reports Server (NTRS)

Farr, Tom G.

1987-01-01

The effectiveness of EOS data as a basis for the study of desert surfaces' evolution is presently evaluated for both long and short term geomorphic evolution. Attention is given to the usefulness of such sensor systems planned for EOS as MODIS for regional vegetation distribution/variability monitoring, HIRIS for visible-near IR observations, TIMS for lithological identification, HMMR and SSMI for soil characteristics, LASA for atmospheric profiles, SAR for surface roughness, ALT for two-dimensional topography, ACR for the calibration of imaging sensors, and ERBE for climate modeling and regional surface albedo variation determinations.

Spatio-temporal variation in groundwater head affected by stratigraphic heterogeneity of the alluvial aquifer in Northwest India

NASA Astrophysics Data System (ADS)

van Dijk, W. M.; Joshi, S. K.; Densmore, A. L.; Jackson, C. R.; Sutanudjaja, E.; Lafare, A. E. A.; Gupta, S.; Mackay, J. D.; Mason, P. J.; Sinha, R.

2017-12-01

Groundwater is a primary source of freshwater in the alluvial aquifer system of northwestern India. Unsustainable exploitation of the groundwater resources has led to a regional hotspot in groundwater depletion. Rapid groundwater-level decline shows spatial variation, as the effects of various stresses, including precipitation, potential evapotranspiration and abstraction, are likely to be influenced by the stratigraphic and geomorphic heterogeneity between sediment fan and interfan areas (see Geomorphological map in Figure A). We used a transfer function-noise (TFN) time series approach to quantify the effect of the various stress components in the period 1974-2010, based on predefined impulse response functions (IRFs) of von Asmuth et al. (2008). The objective of this study was 1) to acquire the impulse response function of various stresses, 2) assess the spatial estimation parameter (the zeroth moment, M0) of the spatial development of the groundwater head and 3) relate the spatial M0 to the observed stratigraphic and geomorphic heterogeneity. We collected information on the groundwater head pre- and post-monsoon, the district-wise monthly precipitation and potential evapotranspiration, and we modeled the monthly abstraction rate using land-use information. The TFN identified the IRF of precipitation as well as abstraction. The IRF, summarized in the parameter M0, identified a hotspot for the abstraction stress (see M0 spatial map for abstraction in Figure B) at the margins of the Sutlej and Yamuna fans. No hotspot is observed for the precipitation stress, but the M0 for precipitation increases with distance from the Himalayan front. At larger distances from the Himalayan front, observed groundwater head rises cannot be explained by the IRFs for the abstraction and precipitation stresses. This is likely because the current TFN models do not account for other stresses, such as recharge by canal leakage, which are locally important. We conclude that the spatial variation in the M0 for abstraction is controlled by stratigraphic and geomorphic heterogeneity. The fan margins and the interfan area are more affected by abstraction as these areas are underlain by fewer, and thinner, aquifer bodies them the fans themselves. Von Ashmuth et al,2008. Ground Water, 46 (1), 30-40

Geomorphic constraints on the evolution of the Kern Gorge, southern Sierra Nevada, California.

NASA Astrophysics Data System (ADS)

Foreshee, B. C.; Krugh, W. C.

2016-12-01

The Kern River is uniquely positioned to respond to tectonic activity that occurs within the southern Sierra Nevada and southern San Joaquin Basin, CA. The North and South forks of the upper Kern River (above Lake Isabella) are fed by tributaries that primarily drain the high-elevation low-relief landscape of the Kern Plateau. These south flowing trunk streams switch to a dominantly southwest flow direction at the Lake Isabella Reservoir and South Lake Valley respectively. Downstream from Lake Isabella, the Kern River steepens as it flows through the Kern Gorge and then crosses the Kern Arch region of the San Joaquin Basin. Clark et al., (2005) used low-temperature thermochronometry and trunk and tributary channel profiles from the upper Kern River catchment to identify two periods of rapid incision that occurred from 32.0 to 3.5 Ma and from 3.5 Ma to present. Cecil et al., (2014) used low-temperature thermochronometry from well cores of Oligocene-Miocene sandstones to investigate the time-temperature history of the Kern Arch and identified a period of subsidence and sedimentation between 6.0 and 1.0 Ma that was immediately followed by rapid exhumation. They attributed these results to the northwest migration of a delaminating lithospheric root. In this study we examine the erosional and depositional history within the Kern Gorge to investigate the response of the Kern River to Pliocene-Pleistocene tectonic activity within the Kern Arch and southern Sierra Nevada. Quantitative stream profile analyses and geomorphic mapping within the Kern Gorge are being conducted using USGS 10m DEM data, satellite and aerial imagery, and field based observations and measurements. Reconnaissance mapping efforts have so far identified several strath terraces, alluvial fill terraces, colluvial deposits, and multiple debris flow and landslide deposits that have been incised by the Kern River and are now preserved above the active channel. These geomorphic landforms are currently being targeted for geochronologic analyses to help constrain depositional ages as well as the timing and rate of incision along the lower Kern River. Combined methods of stream profile analysis, field investigation and geochronometry will shed light on transient signals propagating through the lower Kern River drainage basin.

Assessing Vermont's stream health and biological integrity using artificial neural networks and Bayesian methods

NASA Astrophysics Data System (ADS)

Rizzo, D. M.; Fytilis, N.; Stevens, L.

2012-12-01

Environmental managers are increasingly required to monitor and forecast long-term effects and vulnerability of biophysical systems to human-generated stresses. Ideally, a study involving both physical and biological assessments conducted concurrently (in space and time) could provide a better understanding of the mechanisms and complex relationships. However, costs and resources associated with monitoring the complex linkages between the physical, geomorphic and habitat conditions and the biological integrity of stream reaches are prohibitive. Researchers have used classification techniques to place individual streams and rivers into a broader spatial context (hydrologic or health condition). Such efforts require environmental managers to gather multiple forms of information - quantitative, qualitative and subjective. We research and develop a novel classification tool that combines self-organizing maps with a Naïve Bayesian classifier to direct resources to stream reaches most in need. The Vermont Agency of Natural Resources has developed and adopted protocols for physical stream geomorphic and habitat assessments throughout the state of Vermont. Separate from these assessments, the Vermont Department of Environmental Conservation monitors the biological communities and the water quality in streams. Our initial hypothesis is that the geomorphic reach assessments and water quality data may be leveraged to reduce error and uncertainty associated with predictions of biological integrity and stream health. We test our hypothesis using over 2500 Vermont stream reaches (~1371 stream miles) assessed by the two agencies. In the development of this work, we combine a Naïve Bayesian classifier with a modified Kohonen Self-Organizing Map (SOM). The SOM is an unsupervised artificial neural network that autonomously analyzes inherent dataset properties using input data only. It is typically used to cluster data into similar categories when a priori classes do not exist. The incorporation of a Bayesian classifier allows one to explicitly incorporate existing knowledge and expert opinion into the data analysis. Since classification plays a leading role in the future development of data-enabled science and engineering, such a computational tool is applicable to a variety of proactive adaptive watershed management applications.

Tsunami waves extensively resurfaced the shorelines of an early Martian ocean

PubMed Central

Rodriguez, J. Alexis P.; Fairén, Alberto G.; Tanaka, Kenneth L.; Zarroca, Mario; Linares, Rogelio; Platz, Thomas; Komatsu, Goro; Miyamoto, Hideaki; Kargel, Jeffrey S.; Yan, Jianguo; Gulick, Virginia; Higuchi, Kana; Baker, Victor R.; Glines, Natalie

2016-01-01

It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide impacts, resulting in craters ~30 km in diameter and occurring perhaps a few million years apart. The tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes, which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces. The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement took place following a transition into a colder global climatic regime that occurred after the older tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and resurfacing coastal terrains. PMID:27196957

Tsunami waves extensively resurfaced the shorelines of an early Martian ocean.

PubMed

Rodriguez, J Alexis P; Fairén, Alberto G; Tanaka, Kenneth L; Zarroca, Mario; Linares, Rogelio; Platz, Thomas; Komatsu, Goro; Miyamoto, Hideaki; Kargel, Jeffrey S; Yan, Jianguo; Gulick, Virginia; Higuchi, Kana; Baker, Victor R; Glines, Natalie

2016-05-19

It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide impacts, resulting in craters ~30 km in diameter and occurring perhaps a few million years apart. The tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes, which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces. The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement took place following a transition into a colder global climatic regime that occurred after the older tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and resurfacing coastal terrains.

Discrete simulations of spatio-temporal dynamics of small water bodies under varied stream flow discharges

NASA Astrophysics Data System (ADS)

Daya Sagar, B. S.

2005-01-01

Spatio-temporal patterns of small water bodies (SWBs) under the influence of temporally varied stream flow discharge are simulated in discrete space by employing geomorphologically realistic expansion and contraction transformations. Cascades of expansion-contraction are systematically performed by synchronizing them with stream flow discharge simulated via the logistic map. Templates with definite characteristic information are defined from stream flow discharge pattern as the basis to model the spatio-temporal organization of randomly situated surface water bodies of various sizes and shapes. These spatio-temporal patterns under varied parameters (λs) controlling stream flow discharge patterns are characterized by estimating their fractal dimensions. At various λs, nonlinear control parameters, we show the union of boundaries of water bodies that traverse the water body and non-water body spaces as geomorphic attractors. The computed fractal dimensions of these attractors are 1.58, 1.53, 1.78, 1.76, 1.84, and 1.90, respectively, at λs of 1, 2, 3, 3.46, 3.57, and 3.99. These values are in line with general visual observations.

Eddy covariance measurement of the spatial heterogeneity of surface energy exchanges over Heron Reef, Great Barrier Reef, Australia

NASA Astrophysics Data System (ADS)

MacKellar, M.; McGowan, H. A.; Phinn, S. R.

2011-12-01

Coral reefs cover 2.8 to 6.0 x 105 km2 of the Earth's surface and are warm, shallow regions that are believed to contribute enhanced sensible and latent heat to the atmosphere, relative to the surrounding ocean. To predict the impact of climate variability on coral reefs and their weather and climate including cloud, winds, rainfall patterns and cyclone genesis, accurate parameterisation of air-sea energy exchanges over coral reefs is essential. This is also important for the parameterisation and validation of regional to global scale forecast models to improve prediction of tropical and sub-tropical marine and coastal weather. Eddy covariance measurements of air-sea fluxes over coral reefs are rare due to the complexities of installing instrumentation over shallow, tidal water. Consequently, measurements of radiation and turbulent flux data for coral reefs have been captured remotely (satellite data) or via single measurement sites downwind of coral reefs (e.g. terrestrial or shipboard instrumentation). The resolution of such measurements and those that have been made at single locations on reefs may not capture the spatial heterogeneity of surface-atmosphere energy exchanges due to the different geomorphic and biological zones on coral reefs. Accordingly, the heterogeneity of coral reefs with regard to substrate, benthic communities and hydrodynamic processes are not considered in the characterization of the surface radiation energy flux transfers across the water-atmosphere interface. In this paper we present a unique dataset of concurrent in situ eddy covariance measurements made on instrumented pontoons of the surface energy balance over different geomorphic zones of a coral reef (shallow reef flat, shallow and deep lagoons). Significant differences in radiation transfers and air-sea turbulent flux exchanges over the reef were highlighted, with higher Bowen ratios over the shallow reef flat. Increasing wind speed was shown to increase flux divergence between sites to the extent that under unstable, south-easterly Trade Winds the net flux of heat was positive and negative over different geomorphic zones. The surface drag coefficient ranged from 1 to 2.5 x 10-3, with no significant difference between sites. Results highlight the spatial variation of air-sea energetics across a lagoonal platform reef in response to local meteorology, hydrodynamics and benthic/substrate cover.

Polygonal tundra geomorphological change in response to warming alters future CO2 and CH4 flux on the Barrow Peninsula

USGS Publications Warehouse

Lara, Mark J.; McGuire, A. David; Euskirchen, Eugénie S.; Tweedie, Craig E.; Hinkel, Kenneth M.; Skurikhin, Alexei N.; Romanovsky, Vladimir E.; Grosse, Guido; Bolton, W. Robert; Genet, Helene

2015-01-01

The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate, and extreme scenarios of thermokarst pit formation (10%, 30%, and 50%) reported for Alaskan arctic tundra sites. We developed a 30 × 30 m resolution tundra geomorphology map (overall accuracy:75%; Kappa:0.69) for our ~1800 km² study area composed of ten classes; drained slope, high center polygon, flat-center polygon, low center polygon, coalescent low center polygon, polygon trough, meadow, ponds, rivers, and lakes, to determine their spatial distribution across the Barrow Peninsula. Land-atmosphere CO2 and CH4 flux data were collected for the summers of 2006–2010 at eighty-two sites near Barrow, across the mapped classes. The developed geomorphic map was used for the regional assessment of carbon flux. Results indicate (i) at present during peak growing season on the Barrow Peninsula, CO2 uptake occurs at -902.3 106gC-CO2 day−1(uncertainty using 95% CI is between −438.3 and −1366 106gC-CO2 day−1) and CH4 flux at 28.9 106gC-CH4 day−1(uncertainty using 95% CI is between 12.9 and 44.9 106gC-CH4 day−1), (ii) one century of future landscape change associated with the thaw-lake cycle only slightly alter CO2 and CH4 exchange, while (iii) moderate increases in thermokarst pits would strengthen both CO2uptake (−166.9 106gC-CO2 day−1) and CH4 flux (2.8 106gC-CH4 day−1) with geomorphic change from low to high center polygons, cumulatively resulting in an estimated negative feedback to warming during peak growing season.

Missouri Ozark forest soils: perspectives and realities

Treesearch

R. David. Hammer

1997-01-01

Ozark forest soils are dynamic in space and time, and most formed in multiple parent materials. Erosion and mass movement have been variable and extensive. Soil attributes including texture, cation exchange capacity, and mineralogy are related to geologic strata and to geomorphic conditions. Soil organic carbon content is influenced by surface shape, position in...

Model Verification and Validation Using Graphical Information Systems Tools

DTIC Science & Technology

2013-07-31

Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law , no person shall be...12 Geomorphic Measurements...to a model. Ocean flows, which are organized E-2 current systems, transport heat and salinity and cause water to pile up as a water surface

A geomorphic process law for detachment-limited hillslopes

NASA Astrophysics Data System (ADS)

Turowski, Jens

2015-04-01

Geomorphic process laws are used to assess the shape evolution of structures at the Earth's surface over geological time scales, and are routinely used in landscape evolution models. There are two currently available concepts on which process laws for hillslope evolution rely. In the transport-limited concept, the evolution of a hillslope is described by a linear or a non-linear diffusion equation. In contrast, in the threshold slope concept, the hillslope is assumed to collapse to a slope equal to the internal friction angle of the material when the load due to the relief exists the material strength. Many mountains feature bedrock slopes, especially in the high mountains, and material transport along the slope is limited by the erosion of the material from the bedrock. Here, I suggest a process law for detachment-limited or threshold-dominated hillslopes, in which the erosion rate is a function of the applied stress minus the surface stress due to structural loading. The process law leads to the prediction of an equilibrium form that compares well to the shape of many mountain domes.

A Detailed Study of Debris Flow Source Areas in the Northern Colorado Front Range.

NASA Astrophysics Data System (ADS)

Arana-Morales, A.; Baum, R. L.; Godt, J.

2014-12-01

Nearly continuous, heavy rainfall occurred during 9-13 September 2013 causing flooding and widespread landslides and debris flows in the northern Colorado Front Range. Whereas many recent studies have identified erosion as the most common process leading to debris flows in the mountains of Colorado, nearly all of the debris flows mapped in this event began as small, shallow landslides. We mapped the boundaries of 415 September 2013 debris flows in the Eldorado Springs and Boulder 7.5-minute quadrangles using 0.5-m-resolution satellite imagery. We characterized the landslide source areas of six debris flows in the field as part of an effort to identify what factors controlled their locations. Four were on a dip slope in sedimentary rocks in the Pinebrook Hills area, near Boulder, and the other two were in granitic rocks near Gross Reservoir. Although we observed no obvious geomorphic differences between the source areas and surrounding non-landslide areas, we noted several characteristics that the source areas all had in common. Slopes of the source areas ranged from 28° to 35° and most occurred on planar or slightly concave slopes that were vegetated with grass, small shrubs, and sparse trees. The source areas were shallow, irregularly shaped, and elongated downslope: widths ranged from 4 to 9 m, lengths from 6 to 40 m and depths ranged from 0.7 to 1.2 m. Colluvium was the source material for all of the debris flows and bedrock was exposed in the basal surface of all of the source areas. We observed no evidence for concentrated surface runoff upslope from the sources. Local curvature and roughness of bedrock and surface topography, and depth distribution and heterogeneity of the colluvium appear to have controlled the specific locations of these shallow debris-flow source areas. The observed distribution and characteristics of the source areas help guide ongoing efforts to model initiation of the debris flows.

Landslide-induced river channel avulsions in mountain catchments of southwest New Zealand

NASA Astrophysics Data System (ADS)

Korup, Oliver

2004-11-01

Pulsed or chronic supply of landslide debris to valley floors has historically caused substantial aggradation and channel instability in several alpine catchments of SW New Zealand. In this regional investigation of landslide impacts on river morphology, three types of landslide-induced channel avulsion are discerned: (i) upstream/backwater avulsions, (ii) contact avulsions, and (iii) downstream/loading avulsions. The basis for this qualitative geomorphic process-response framework is the principal direction of fluvial response with respect to its position relative to the causative landslide emplacement site. Downstream avulsions have the highest damage potential to land use and infrastructure on unconfined mountain-fringe alluvial fans. In the wake of such events, catastrophic aggradation may obliterate up to several km 2 of mature floodplain forests by burial under several metres within a few decades. Estimates of mean aggradation rates are high (<220 mm year -1) and exceed long-term (10 3 year) trends of fluvial degradation by an order of magnitude. Future potential avulsion routeways may be detected by geomorphic mapping of abandoned channels, which are preferentially reactivated in the wake of landslide-induced sediment waves.

Cultural Resources Survey of Greenwood Bend and Iowa Point Revetment, Mississippi River M-293.1 to 280-L

DTIC Science & Technology

1993-10-01

as Mesoamerica (Neuman 1984:218). Sometime after A.D. 1000, the Plaquemine phenomenon, originally defined by the Medora Site (16WBR1), continued the...the surface in the study area. Commonly called the Tunica Hills, it corresponds closely with the area originally delineated as the Citronelle...of dissection and structural influence, the original geomorphic expression of the surface has been obliterated, and depositional environment is best

Fluvio geomorphic set-up of Noctis Fossae in Noctis Labyrinthus of Syria-Planum Provenance, Mars

NASA Astrophysics Data System (ADS)

Chavan, A. A.; Bhandari, S.

2017-12-01

The modern era of planetary exploration has revealed fluvial or fluvial like landforms on the extraterrestrial surfaces of planets and moons of our solar system. This has posed as interesting challenges for advancing our fundamental understanding of fluvial processes and their associated landforms on the planetary surfaces especially on Mars. It has been recognized through earlier studies that the channels and valleys are extensively dissected on Mars. The Valleys are low lying, elongate troughs surrounded by elevated topography. Moreover, valley networks on Mars are the most noticeable features attesting that different geological processes and possibly climatic conditions prevailed in the past and played a vital role in formulating the Martian topography. Channel incisions which are a domino effect both tectonic and surface runoff and groundwater sapping. The components of surface runoff have been deciphered with the help of morphometric exercises. Further, the geomorphological studies of these landforms are critical in understanding the regional tectonics. The present work is an assessment of Fluvio geomorphic set-up of Noctis Fossae in Noctis Labyrinthus of Syria-Planum Provenance, Mars. This study focuses on the fluvio geomorphology of the southern highlands (00 to 400S to 850-1200W) to determine how these features were formed, which process formed these valleys and includes the probable causes resulting into the development of the topography. Keywords: Noctis Fossae; Noctis Labyrinthus; Syria Planum; Mars

Erosion and Deposition Monitoring Using High-Density Aerial Lidar and Geomorphic Change Detection Software Analysis at Los Alamos National Laboratory, Los Alamos New Mexico, LA-UR-17-26743

NASA Astrophysics Data System (ADS)

Walker, T.; Kostrubala, T. L.; Muggleton, S. R.; Veenis, S.; Reid, K. D.; White, A. B.

2017-12-01

The Los Alamos National Laboratory storm water program installed sediment transport mitigation structures to reduce the migration of contaminants within the Los Alamos and Pueblo (LA/P) watershed in Los Alamos, NM. The goals of these structures are to minimize storm water runoff and erosion, enhance deposition, and reduce mobility of contaminated sediments. Previous geomorphological monitoring used GPS surveyed cross-sections on a reach scale to interpolate annual geomorphic change in sediment volumes. While monitoring has confirmed the LA/P watershed structures are performing as designed, the cross-section method proved difficult to estimate uncertainty and the coverage area was limited. A new method, using the Geomorphic Change Detection (GCD) plugin for ESRI ArcGIS developed by Wheaton et al. (2010), with high-density aerial lidar data, has been used to provide high confidence uncertainty estimates and greater areal coverage. Following the 2014 monsoon season, airborne lidar data has been collected annually and the resulting DEMs processed using the GCD method. Additionally, a more accurate characterization of low-amplitude geomorphic changes, typical of low-flow/low-rainfall monsoon years, has been documented by applying a spatially variable error to volume change calculations using the GCD based fuzzy inference system (FIS). The FIS method allows for the calculation of uncertainty based on data set quality and density e.g. point cloud density, ground slope, and degree of surface roughness. At the 95% confidence level, propagated uncertainty estimates of the 2015 and 2016 lidar DEM comparisons yielded detectable changes greater than 0.3 m - 0.46 m. Geomorphic processes identified and verified in the field are typified by low-amplitude, within-channel aggradation and incision and out of channel bank collapse that over the course of a monsoon season result in localized and dectetable change. While the resulting reach scale volume change from 2015 - 2016 was often nonsignificant, it is estimated with a higher degree of confidence than the previous cross-section/interpolation method. Results from comparisons of the recent low-intensity rainfalls/storm peak discharges monsoon season DEMs have established the expected amount of geomorphic change to be minor and localized, yet demonstrable.

SOC in Different Land Use Types: does Geomorphic Position Matter?

NASA Astrophysics Data System (ADS)

Hu, Y.; Sun, Q.; Wang, R.; Wang, Z.; Guo, S.

2016-12-01

Substantial research has been devoted to land use conversion induced changes of soil organic carbon (SOC) and total nitrogen (TN). However, most of the studies were based on local field plots, featuring single predominant landform (ex. rolling topography in Denmark, or Great Plain in the US). For regions integrated from complex landforms such as the Chinese Loess Plateau where tableland, sloping land and gullies are closely networked and each collectively covers a third of the area, the effects of land use changes to SOC and TN could spatially differ among geomorphic positions. So far, local farming management and policies on the Loess Plateau have often been guided by reports from single landform. To fully understand the potential effects of land use conversions to regional C and N cycling, a systematic investigation is highly in need to identify the relative contributions from different geomorphic positions. In this study on the Chinese Loess Plateau, soil profiles deep to 200 cm on three geomorphic positions (tableland, sloping land and gullies) were investigated, each having four types of land use (cropland, orchard, grassland, and woodland). The SOC and total N were measured and compared every layer of 20 cm. Our results show that: 1) the SOC stocks and TN in the surface soil (0-20 cm) was most enriched in downslope gullies and least stored in the summit tableland, demonstrating the erosional redistribution of SOC and TN along hillslopes. 2) After converting from cropland to grassland or woodland, the SOC stocks and TN in soil layer < 60 cm were significantly increased by 17-57% and 40-49%, demonstrating the benefits of land use conversion on SOC sequestration and N cycling. 3) More specifically, such positive increase of SOC stocks was more pronounced in the gullies than on the sloping land. 4) While the SOC stocks and TN in deep layers > 60 cm were more enriched on the tableland, the effects of land use conversions did not differ among the three geomorphic positions. Given the complexity of geomorphology on the Loess Plateau and its relevance of land use changes to regional ecosystem in China, the differentiated changes of SOC stocks and TN observed on tableland, sloping land and gullies highlight the necessity to properly account for the potential influence of geomorphic positions for each combination of land use and conversion.

Slopes, Fans, Terraces and their Soils - A three Systems Approach for Estimating Future Climate and Land-Use Change

NASA Astrophysics Data System (ADS)

Voelkel, J.; Bens, O.; Eden, M.; Ramisch, A.

2015-12-01

Semiarid and arid landscapes in Namibia and the South African Republic (RAS) are sensitive to changes in the vegetation that covers and protects the surface. Climatic changes or anthropogenic influences such as farming, grazing and ploughing can degrade the landscape if the natural stability of the landscape and its capacity potential is exceeded. This will directly cause sediment mobilisation and deposition. We intend to examine the connections between earth-surface processes on slopes such as sheet wash, colluvial sediment transport, and eolian movements and their links to the fluvial system via three major geomorphic forms: slopes, fans, and terraces. This novel approach will be undertaken at three study sites in Namibia and RSA In their combination the geomorphic forms have the potential of being high-resolution geoarchives of surface changes ranging from the local to the regional scale. The source and depositional environments of the sediments will be characterised and a chronology of the erosion and deposition within these three geomorphic systems will be established using absolute dating techniques. Thus, activity and stability phases will be worked out mainly for the last three centuries up to a maximum of ~ 1000 years. This offers the possibility to compare the time scales with low human impact to those with intensive human impact (farming/grazing) on the landscape together with known climatic variation and analyze major forcings of the formation of slopes-fans-terraces-systems. Our results will provide answers on how much ecosystem services are and have been influenced either by climate or land use changes in the example regions, to better enable the decision and policy makers to select better managerial options and development plans. - The project "GeoArchives" is funded within the "SPACES" program (Science Partnerships for the Assessment of Complex Earth System Processes) by the Federal Ministry of Education and Research BMBF.

Hydraulic and Geomorphic Assessment of the Merced River and Historic Bridges in Eastern Yosemite Valley, Yosemite National Park, California: Sacramento, California

USGS Publications Warehouse

Minear, J. Toby; Wright, Scott A.

2013-01-01

The Merced River in the popular and picturesque eastern-most part of Yosemite Valley in Yosemite National Park, California, USA, has been extensively altered since the park was first conceived in 1864. Historical human trampling of streambanks has been suggested as the cause of substantial increases in stream width, and the construction of undersized stone bridges in the 1920s has been suggested as the major factor leading to an increase in overbank flooding due to deposition of bars and islands between the bridges. In response, the National Park Service at Yosemite National Park (YNP) requested a study of the hydraulic and geomorphic conditions affecting the most-heavily influenced part of the river, a 2.4-km reach in eastern Yosemite Valley extending from above the Tenaya Creek and Merced River confluence to below Housekeeping Bridge. As part of the study, present-day conditions were compared to historical conditions and several possible planning scenarios were investigated, including the removal of an elevated road berm and the removal of three undersized historic stone bridges identified by YNP as potential problems: Sugar Pine, Ahwahnee and Stoneman Bridges. This Open-File Report will be superseded at a later date by a Scientific Investigations Report. A two-dimensional hydrodynamic model, the USGS FaSTMECH (Flow and Sediment Transport with Morphological Evolution of Channels) model, within the USGS International River Interface Cooperative (iRIC) model framework, was used to compare the scenarios over a range of discharges with annual exceedance probabilities of 50-, 20-, 10-, and 5- percent. A variety of topographic and hydraulic data sources were used to create the input conditions to the hydrodynamic model, including aerial LiDAR (Light Detection And Ranging), ground-based LiDAR, total station survey data, and grain size data from pebble counts. A digitized version of a historical topographic map created by the USGS in 1919, combined with estimates of grain size, was used to simulate historical conditions, and the planning scenarios were developed by altering the present-day topography. Roughness was estimated independently of measured water-surface elevations by using the mapped grain-size data and the Keulegan relation of grain size to drag coefficient. The FaSTMECH hydrodynamic model was evaluated against measured water levels by using a 130.9 m3 s-1 flow (approximately a 33-percent annual exceedance probability flood) with 36 water-surface elevations measured by YNP personnel on June 8, 2010. This evaluation run had a root mean square error of 0.21 m between the simulated- and observed water-surface elevations (less than 10 percent of depth), though the observed water-surface elevations had relatively high variation due to the strong diurnal stage changes over the course of the 4.4-hour collection period, during which discharge varied by about 15 percent. There are presently no velocity data with which to test the model. A geomorphic assessment was performed that consisted of an estimate of the magnitude and frequency of bedload and suspended-sediment transport at “Tenaya Bar”, an important gravel-cobble bar located near the upstream end of the study site that determines the amount of flow across the floodplain at the Sugar Pine – Ahwahnee bend. An analysis of select repeat cross-sections collected by YNP since the late 1980s was done to investigate changes in channel cross-sectional area near the Tenaya Bar site. The results of the FaSTMECH models indicate that the maximum velocities in the present-day channel within the study reach are associated with Stoneman and Sugar Pine Bridges, at close to 3.0 m s-1 for the 5-percent annual exceedance probability flood. The modeled maximum velocities at Ahwahnee Bridge are comparatively low, at between 1.5 and 2.0 m s-1, most likely due to the bridge's orientation parallel to down-valley floodplain flows. The results of the FaSTMECH models for the bridge removal scenarios indicate a reduction in average velocity at the bridge sites for the range of flows by approximately 23-38 percent (Sugar Pine Bridge), 32-42 percent (Ahwahnee Bridge), and 33-39 percent (Stoneman Bridge), though a side channel of concern to YNP management did not appear to be substantially affected by the removal scenarios. In comparison to the historical data, the FaSTMECH results suggest that flows for present-day conditions do not inundate the floodplain until between the 50- and 20-percent annual exceedance probability flood, whereas historically, a large portion of the floodplain was inundated during the 50-percent annual exceedance probability flood. Modeled maximum velocities in the present-day channel commonly exceed 2.0 m s-1, whereas with the historical scenario, modeled maximum in-channel velocities rarely exceeded 2.0 m s-1. The geomorphic analysis of the magnitude-frequency of bedload and suspended-sediment transport suggests that at the important Tenaya Bar site, the majority of bed sediment is mobile during most snowmelt-dominated floods. In contrast to sediment transport capacity, the analysis of repeat cross-sections suggests that bedload sediment supply into the eastern Yosemite Valley may be quite different between rain-on-snow floods and snowmelt-dominated floods, potentially with most sediment supply occurring during rain-on-snow floods, such as the 1997 flood. In contrast, the magnitude-frequency analysis of bedload and suspended-sediment transport suggests that long-term bedload sediment transport is likely dominated by snowmelt floods, and suspended-sediment transport is relatively low compared to bedload transport. Obtaining measured velocity data throughout the study reach would aid in model calibration, and thus would improve confidence in model results. Improved confidence in the model velocity results would allow additional substantial analyses of reach-scale effects of the planning scenarios and would enable the development of geomorphic models to evaluate the long-term geomorphic responses of the site. In addition, the collection of watershed sediment-supply data, about which little is presently known, would give planners helpful tools to plan restoration scenarios for this nationally important river.

Constraints on the Miocene landscape evolution of the Eastern Alps from the Kalkspitze region, Niedere Tauern (Austria)

NASA Astrophysics Data System (ADS)

Dertnig, Florian; Stüwe, Kurt; Woodhead, Jon; Stuart, Finlay M.; Spötl, Christoph

2017-12-01

In order to unravel aspects of the Miocene landscape evolution of the eastern European Alps, we present geomorphic and isotopic data from the western Niedere Tauern region (Austria). The region is critical for such interpretations, because it is one of the few regions along the topographic axis of the Eastern Alps where the highest peaks (up to 2500 m a.s.l.) are dominated by limestone. As such, the region contains a record of Miocene landscape-forming events that survived the Pleistocene glaciations, not preserved elsewhere in the central Eastern Alps. This record includes karst caves, karstified planation surfaces and crystalline fluvial pebbles (Augenstein Formation) preserved on planation surfaces and in karst caves. Caves in the region occur in three distinct levels that correlate with well-known cave levels in the Northern Calcareous Alps, although they are somewhat higher in the Niedere Tauern. In part, these cave elevations also correlate with three planation surfaces and knickpoints of major streams draining the region, testifying their pre-glacial origin. We report details of a karst cave (Durchgangshöhle) from the highest cave level located at 2340 m a.s.l. In this cave, allochthonous fluvial gravels are present, overgrown by speleothems. One speleothem yielded an early middle Pleistocene U-Pb age (682 ± 17 ka). We regard this as a minimum age for the erosion of the fluvial cave deposits during Marine Isotope Stages 17 or 16. Carbon and oxygen isotope data of these speleothems imply a climate that is consistent with this interpretation. Cosmogenic 21Ne data of fluvial quartz clasts collected from the surface on plateaus of the Northern Calcareous Alps suggest minimum exposure durations of 115 and 262 ka. They probably reflect successive exposure since removal of the sediment cover of the Oligocene Augenstein Formation during the Pleistocene. While our geochronological data fail to record aspects of the earlier Miocene uplift history, they are consistent with the overall geomorphic history inferred from the geomorphic markers. This suggests that the Niedere Tauern share a common uplift history with the Northern Calcareous Aps and implies a moderate south-north topographic gradient that has been maintained since the Miocene.

Trends of the gully erosion development in the territory of the Republic of Tatarstan

NASA Astrophysics Data System (ADS)

Medvedeva, R. A.

2018-01-01

Gully erosion is one of the most active geomorphic processes and one of the major cause of land degradation worldwide. The aim of the study was identifying the dynamics of gully erosion development in the Republic of Tatarstan. The interpretation of satellite images were used for evaluation of the modern dynamics of gullies. Two key indicators of gully erosion (length density and gully head density) were determined. Maps of modern gully erosion for a part of the Republic of Tatarstan were constructed.

Stream power framework for predicting geomorphic change: The 2013 Colorado Front Range flood

NASA Astrophysics Data System (ADS)

Yochum, Steven E.; Sholtes, Joel S.; Scott, Julian A.; Bledsoe, Brian P.

2017-09-01

The Colorado Front Range flood of September 2013 induced a diverse range of geomorphic changes along numerous stream corridors, providing an opportunity to assess responses to a large flood in a semiarid landscape. We defined six classes of geomorphic change related to peak unit stream power and valley confinement for 531 stream reaches over 226 km, spanning a gradient of channel scales and slope. Geomorphic change was generally driven by erosion of channel margins in confined reaches and by a combination of deposition and erosion in unconfined reaches. The magnitude of geomorphic change typically increased with unit stream power (ω), with greater responses observed in unconfined channels. Cumulative logit modeling indicated that total stream power or unit stream power, unit stream power gradient, and valley confinement are significant predictors of geomorphic response for this flood event. Based on this dataset, thresholds for geomorphic adjustment were defined. For channel slopes < 3%, we noted a credible potential for substantial channel widening with ω > 230 W/m2 (16 lb/ft-s; at least 10% of the investigated sites experienced substantial channel widening) and a credible potential for avulsions, braiding, and loss of adjacent road embankments associated with ω > 480 W/m2 (33 lb/ft-s; at least 10% of the investigated sites experienced such geomorphic change). Infrequent to numerous eroded banks were very likely with ω > 700 W/m2 (48 lb/ft-s), with substantial channel widening or major geomorphic change shifting from credible to likely. Importantly, in reaches where there were large reductions in ω as the valley form shifted from confined to relatively unconfined, large amounts of deposition-induced, reach-scale geomorphic change occurred in some locations at relatively low ω. Additionally, alluvial channels with slopes > 3% had greater resistance to geomorphic change, likely caused by armoring by larger bed material and increased flow resistance from enhanced bedforms. Finally, we describe how these results can potentially be used by practitioners for assessing the risk of geomorphic change when evaluating current or planned conditions.

Geologic Map of the Hellas Region of Mars

USGS Publications Warehouse

Leonard, Gregory J.; Tanaka, Kenneth L.

2001-01-01

INTRODUCTION This geologic map of the Hellas region focuses on the stratigraphic, structural, and erosional histories associated with the largest well-preserved impact basin on Mars. Along with the uplifted rim and huge, partly infilled inner basin (Hellas Planitia) of the Hellas basin impact structure, the map region includes areas of ancient highland terrain, broad volcanic edifices and deposits, and extensive channels. Geologic activity recorded in the region spans all major epochs of martian chronology, from the early formation of the impact basin to ongoing resurfacing caused by eolian activity. The Hellas region, whose name refers to the classical term for Greece, has been known from telescopic observations as a prominent bright feature on the surface of Mars for more than a century (see Blunck, 1982). More recently, spacecraft imaging has greatly improved our visual perception of Mars and made possible its geologic interpretation. Here, our mapping at 1:5,000,000 scale is based on images obtained by the Viking Orbiters, which produced higher quality images than their predecessor, Mariner 9. Previous geologic maps of the region include those of the 1:5,000,000-scale global series based on Mariner 9 images (Potter, 1976; Peterson, 1977; King, 1978); the 1:15,000,000-scale global series based on Viking images (Greeley and Guest, 1987; Tanaka and Scott, 1987); and detailed 1:500,000-scale maps of Tyrrhena Patera (Gregg and others, 1998), Dao, Harmakhis, and Reull Valles (Price, 1998; Mest and Crown, in press), Hadriaca Patera (D.A. Crown and R. Greeley, map in preparation), and western Hellas Planitia (J.M. Moore and D.E. Wilhelms, map in preparation). We incorporated some of the previous work, but our map differs markedly in the identification and organization of map units. For example, we divide the Hellas assemblage of Greeley and Guest (1987) into the Hellas Planitia and Hellas rim assemblages and change the way units within these groupings are identified and mapped (table 1). The new classification scheme includes broad, geographically related categories and local, geologically and geomorphically related subgroups. Because of our mapping at larger scale, many of our map units were incorporated within larger units of the global-scale mapping (see table 1). Available Viking images of the Hellas region vary greatly in several aspects, which has complicated the task of producing a consistent photogeologic map. Best available image resolution ranges from about 30 to 300 m/pixel from place to place. Many images contain haze caused by dust clouds, and contrast and shading vary among images because of dramatic seasonal changes in surface albedo, opposing sun azimuths, and solar inclination. Enhancement of selected images on a computer-display system has greatly improved our ability to observe key geologic relations in several areas. Determination of the geologic history of the region includes reconstruction of the origin and sequence of formation, deformation, and modification of geologic units constituting (1) the impact-basin rim and surrounding highlands, (2) volcanic and channel assemblages on the northeast and south sides of the basin, (3) interior basin deposits, and (4) slope and surficial materials throughout the map area. Various surface modifications are attributed to volcanic, fluvial, eolian, mass-wasting, and possibly glacial and periglacial processes. Structures include basin faults (mostly inferred), wrinkle ridges occurring mainly in volcanic terrains and interior plains, volcanic collapse craters, and impact craters. Our interpretations in some cases rely on previous work, but in many significant cases we have offered new interpretations that we believe are more consistent with the observations documented by our mapping. Our primary intent for this mapping has been to elucidate the history of emplacement and modification of Hellas Planitia materials, which form the basis for analysis of their r

Surface response of blind thrust shown from high resolution topographic data and updated geochronology at Wheeler Ridge, CA

NASA Astrophysics Data System (ADS)

Kleber, E.; Arrowsmith, R.; DeVecchio, D. E.; Johnstone, S. A.; Rittenour, T. M.

2015-12-01

Wheeler Ridge is an asymmetric east-propagating anticline (10km axis, 330m relief) above a north-vergent blind thrust deforming Quaternary alluvial fan and shallow marine rocks at the northern front of the Transverse Ranges, San Joaquin Valley, CA. This area was a research foci in the 1990's when the soils, u-series soil carbonate dating, and subsurface structure of deformed strata identified from oil wells were used to create a kinematic model of deformation, and estimates of fault slip, uplift, and lateral propagation rates. A recent collection of light detection and ranging (lidar) topographic data and optically stimulated luminescence (OSL) data allow us to complete meter scale topographic analyses of the fluvial networks and hillslopes and correlate geomorphic response to tectonics. We interpret these results using a detailed morphological map and observe drainage network and hillslope process transitions both along and across the fold axis. With lidar topography, we extract common morphometrics (e.g., channel steepness-- ksn, eroded volume, hillslope relief) to illustrate how the landscape is responding to variations in uplift rate along the fold axis and show asymmetry of surface response on the forelimb and backlimb. The forelimb is dominated by large drainages with landslides initiating in the marine units at the core of the fold. Our topographic analysis shows that the stream channel indices values on the forelimb increase along the fold axis, away from the propagation tip. The backlimb drainages are dominantly long and linear with broad ridgelines. Using lidar and fieldwork, we see that uplifted backlimb surfaces preserve the deformed fan surface. The preliminary OSL results from alluvial fan units improve age control of previously defined surfaces, refining our understanding of the deposition and uplift of alluvial fan units on preserved on backlimb.

Late Quaternary activity of the Ecemiş Fault Zone, Turkey; implications from cosmogenic 36Cl dating of offset alluvial fans

NASA Astrophysics Data System (ADS)

Akif Sarıkaya, Mehmet; Yıldırım, Cengiz; Çiner, Attila

2014-05-01

The Ecemiş Fault Zone is the southernmost segment of the Central Anatolian Fault Zone. The tectonic trough of the fault zone defines the boundary between the Central and Eastern Taurides Ranges. The presence of faulted alluvial fans and colluvium within this trough provide favorable conditions to unravel the Late Quaternary slip-rate of the fault zone by cosmogenic surface exposure dating. In this context, we focused on the main strand of the fault zone and also on the Cevizlik Fault that delimits the mountain front of the Aladaǧlar, Eastern Taurides. Geomorphic mapping and topographic surveying indicate four different alluvial fan levels deposited along the main strand. Our topographic survey reveals 60±5 m horizontal and 18±2 m vertical displacement of the oldest fan surface (AF1) associated with the main strand of the fault zone. We dated the surface of the AF1 with 13 cosmogenic 36Cl samples. Our results indicate that the AF1 surface was abandoned maximum 105.3±1.5 ka ago. Accordingly, we propose 0.57±0.05 mm/yr horizontal and 0.17±0.02 mm/yr vertical mean slip-rates since 100 ka for the main strand. On the other hand, we measured 20±2 m vertical displacement on the colluvium along the Cevizlik Fault. The surface exposure age of the colluvium yielded 21.9±0.3 ka that translates to 0.91±0.09 mm/yr vertical slip-rate for the Cevizlik Fault. Our results reveal significant Quaternary deformation, and low strain rates might indicate very long earthquake recurrence intervals along the fault zone.

Dating young geomorphic surfaces using age of colonizing Douglas fir in southwestern Washington and northwestern Oregon, USA

USGS Publications Warehouse

Pierson, T.C.

2007-01-01

Dating of dynamic, young (<500 years) geomorphic landforms, particularly volcanofluvial features, requires higher precision than is possible with radiocarbon dating. Minimum ages of recently created landforms have long been obtained from tree-ring ages of the oldest trees growing on new surfaces. But to estimate the year of landform creation requires that two time corrections be added to tree ages obtained from increment cores: (1) the time interval between stabilization of the new landform surface and germination of the sampled trees (germination lag time or GLT); and (2) the interval between seedling germination and growth to sampling height, if the trees are not cored at ground level. The sum of these two time intervals is the colonization time gap (CTG). Such time corrections have been needed for more precise dating of terraces and floodplains in lowland river valleys in the Cascade Range, where significant eruption-induced lateral shifting and vertical aggradation of channels can occur over years to decades, and where timing of such geomorphic changes can be critical to emergency planning. Earliest colonizing Douglas fir (Pseudotsuga menziesii) were sampled for tree-ring dating at eight sites on lowland (<750 m a.s.l.), recently formed surfaces of known age near three Cascade volcanoes - Mount Rainier, Mount St. Helens and Mount Hood - in southwestern Washington and northwestern Oregon. Increment cores or stem sections were taken at breast height and, where possible, at ground level from the largest, oldest-looking trees at each study site. At least ten trees were sampled at each site unless the total of early colonizers was less. Results indicate that a correction of four years should be used for GLT and 10 years for CTG if the single largest (and presumed oldest) Douglas fir growing on a surface of unknown age is sampled. This approach would have a potential error of up to 20 years. Error can be reduced by sampling the five largest Douglas fir instead of the single largest. A GLT correction of 5 years should be added to the mean ring-count age of the five largest trees growing on the surface being dated, if the trees are cored at ground level. This correction would have an approximate error of ??5 years. If the trees are cored at about 1.4 m above the round surface (breast height), a CTG correction of 11 years should be added to the mean age of the five sampled trees (with an error of about ??7 years).

Geomorphic change in the Limitrophe reach of the Colorado River in response to the 2014 delta pulse flow, United States and Mexico

USGS Publications Warehouse

Mueller, Erich R.; Schmidt, John C.; Topping, David; Grams, Paul E.

2015-01-01

A pulse of water was released from Morelos Dam into the dry streambed of the Colorado River in its former delta on March 23, 2014. Although small in relation to delta floods of a century ago, this was the first flow to reach the sea in nearly two decades. The pulse flow was significant in that it resulted from an international agreement, Minute 319, which allowed Colorado River water to be used for environmental restoration. Here we present a historical perspective of channel change and the results of geomorphic and sediment transport monitoring during the pulse flow between Yuma, Arizona and San Luis Rio Colorado, Sonora. This reach is known as the Limitrophe, because the river channel is the legal border between the United States and Mexico. Peak discharge of the pulse flow was 120 m3/s at Morelos Dam, but decreased to 71 m3/s at the southern border because of infiltration losses to the dry streambed. In contrast, flood flows in the 1980s and 1990s peaked above 600 m3/s at the southern border, and high flows above 200 m3/s were common. The sustained high flows in the 1980s caused widening and reworking of the river channel downstream through the delta. In the Limitrophe, flooding in 1993 from the Gila River basin dissected the 1980s flood surfaces, and smaller floods in the late 1990s incised the modern “active” channel within these higher surfaces. Field observations show that most geomorphic change during the pulse flow was confined to this pre-pulse, active channel. Relatively little bank erosion was evident, particularly in upstream reaches where vegetation is most dense, but new sandbars formed in areas of flow expansion. Farther downstream, localized bed scour and deposition ranged from 10s of centimeters to more than a meter, and fluvial dunes aggraded the bed in several locations. Measurable suspended-sediment transport occurred throughout the Limitrophe. Sediment concentrations peaked during the rising limb, and suspended sand concentrations suggest deposition in the lower 7 km of the Limitrophe as the channel gradient decreases by an order of magnitude. The pulse flow was small compared to historic floods, and flood magnitudes greater than the 2014 pulse flow are therefore necessary to significantly rework stable geomorphic surfaces or induce channel widening.

Controls on meadow distribution and characteristics [chapter 2

Treesearch

Dru Germanoski; Jerry R. Miller; Mark L. Lord

2011-01-01

Meadow complexes are located in distinct geomorphic and hydrologic settings that allow groundwater to be at or near the ground surface during at least part of the year. Meadows are manifestations of the subsurface flow system, and their distribution is controlled by factors that cause localized zones of groundwater discharge. Knowledge of the factors that serve as...

Advances in planetary geology, volume 2

NASA Technical Reports Server (NTRS)

1986-01-01

This publication is a continuation of volume 1; it is a compilation of reports focusing on research into the origin and evolution of the solar system with emphasis on planetary geology. Specific reports include a multispectral and geomorphic investigation of the surface of Europa and a geologic interpretation of remote sensing data for the Martian volcano Ascreaus Mons.

GIS- and field based mapping of geomorphological changes in a glacier retreat area: A case study from the Kromer valley, Silvretta Alps (Austria)

NASA Astrophysics Data System (ADS)

Guttmann, Markus; Pöppl, Ronald

2017-04-01

Global warming results in an ongoing retreat of Alpine glaciers, leaving behind large amounts of easily erodible sediments. As a consequence processes like rockfalls, landslides and debris flows as well as fluvial processes occur more frequently in pro- and paraglacial areas, often involving catastrophic consequences for humans and infrastructure in the affected valleys. The main objective of the presented work was to map and spatially quantify glacier retreat and geomorphological changes in the Kromer valley, Silvretta Alps (Austria) by applying GIS- and field-based geomorphological mapping. In total six geomorphological maps (1950s, 1970s, 2001, 2006, 2012, and 2016) were produced and analyzed in the light of the study aim. First results have shown a significant decrease of total glaciated area from 96 ha to 53 ha which was accompanied by increased proglacial geomorphic activity (i.e. fluvial processes, rockfalls, debris flows, shallow landslides) in the last 15 years. More detailed results will be presented at the EGU General Assembly 2017.

Investigation and hazard assessment of the 2003 and 2007 Staircase Falls rock falls, Yosemite National Park, California, USA

USGS Publications Warehouse

Wieczorek, G.F.; Stock, Gregory M.; Reichenbach, P.; Snyder, J.B.; Borchers, J.W.; Godt, J.W.

2008-01-01

Since 1857 more than 600 rock falls, rock slides, debris slides, and debris flows have been documented in Yosemite National Park, with rock falls in Yosemite Valley representing the majority of the events. On 26 December 2003, a rock fall originating from west of Glacier Point sent approximately 200 m 3 of rock debris down a series of joint-controlled ledges to the floor of Yosemite Valley. The debris impacted talus near the base of Staircase Falls, producing fragments of flying rock that struck occupied cabins in Curry Village. Several years later on 9 June 2007, and again on 26 July 2007, smaller rock falls originated from the same source area. The 26 December 2003 event coincided with a severe winter storm and was likely triggered by precipitation and/or frost wedging, but the 9 June and 26 July 2007 events lack recognizable triggering mechanisms. We investigated the geologic and hydrologic factors contributing to the Staircase Falls rock falls, including bedrock lithology, weathering, joint spacing and orientations, and hydrologic processes affecting slope stability. We improved upon previous geomorphic assessment of rock-fall hazards, based on a shadow angle approach, by using STONE, a three-dimensional rock-fall simulation computer program. STONE produced simulated rock-fall runout patterns similar to the mapped extent of the 2003 and 2007 events, allowing us to simulate potential future rock falls from the Staircase Falls detachment area. Observations of recent rock falls, mapping of rock debris, and simulations of rock fall runouts beneath the Staircase Falls detachment area suggest that rock-fall hazard zones extend farther downslope than the extent previously defined by mapped surface talus deposits.

Using dye tracing to establish groundwater flow paths in a limestone marble aquifer, University of California, Santa Cruz, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, J.; Bertschinger, V.; Aley, T.

1993-04-01

Areas underlain by karst aquifers are characterized by soluble rock with sinkholes, caves, and a complex underground drainage network. Groundwater issues such as flow direction, well pumping impacts, spring recharge areas, and potential contamination transport routes are greatly complicated by the unique structure of karst aquifers. Standard aquifer analysis techniques cannot be applied unless the structure of the karst aquifer is understood. Water soluble fluorescent dyes are a powerful tool for mapping the irregular subsurface connections and flow paths in karst aquifers. Mapping the subsurface connections allows reasonable estimates of the hydrologic behavior of the aquifer. Two different fluorescent dyesmore » were injected at two points in a limestone karst aquifer system beneath the University of California, Santa Cruz campus. Flow paths in the marble were thought to be closely tied to easily recognized geomorphic alignments of sinkholes associated with fault and fracture zones. The dye tests revealed unexpected and highly complex interconnections. These complex flow paths only partially corresponded to previous surface mapping and aerial photo analysis of fracture systems. Several interfingering but hydrologically unconnected flow paths evidently exist within the cavernous aquifer. For example, dye did not appear at some discharge springs close to the dye injection points, but did appear at more distant springs. This study shows how a dye tracing study in a small, well-defined limestone body can shed light on a variety of environmental and hydrological issues, including potential well pumping impact areas, wellhead protection and recharge areas, parking lot runoff injection to aquifers, and drainage routes from hazardous materials storage areas.« less

Episodes of fluvial and volcanic activity in Mangala Valles, Mars

PubMed Central

Keske, Amber L.; Hamilton, Christopher W.; McEwen, Alfred S.; Daubar, Ingrid J.

2017-01-01

A new mapping-based study of the 900-km-long Mangala Valles outflow system was motivated by the availability of new high-resolution images and continued debates about the roles of water and lava in outflow channels on Mars. This study uses photogeologic analysis, geomorphic surface mapping, cratering statistics, and relative stratigraphy. Results show that Mangala Valles underwent at least two episodes of fluvial activity and at least three episodes of volcanic activity during the Late Amazonian. The occurrence of scoured bedrock at the base of the mapped stratigraphy, in addition to evidence provided by crater retention ages, suggests that fluvial activity preceded the deposition of two of the volcanic units. Crater counts performed at 30 locations throughout the area have allowed us to construct the following timeline: (1) formation of Noachian Highlands and possible initial flooding event(s) before ~1 Ga, (2) emplacement of Tharsis lava flows in the valley from ~700 to 1000 Ma, (3) a megaflooding event at ~700–800 Ma sourced from Mangala Fossa, (4) valley fill by a sequence of lava flows sourced from Mangala Fossa ~400–500 Ma, (5) another megaflooding event from ~400 Ma, (6) a final phase of volcanism sourced from Mangala Fossa ~300–350 Ma, and (7) emplacement of eolian sedimentary deposits in the northern portion of the valley ~300 Ma. These results are consistent with alternating episodes of aqueous flooding and volcanism in the valles. This pattern of geologic activity is similar to that of other outflow systems, such as Kasei Valles, suggesting that there is a recurring, and perhaps coupled, nature of these processes on Mars. PMID:29176911

Geomorphology of Titan's polar terrains: Using the landscape's topographic form to constrain surface processes

NASA Astrophysics Data System (ADS)

Birch, S. P.; Hayes, A. G., Jr.; Dietrich, W. E.; Howard, A. D.; Malaska, M. J.; Moore, J. M.; Mastrogiuseppe, M.; White, O. L.; Hofgartner, J. D.; Soderblom, J. M.; Barnes, J. W.; Bristow, C.; Kirk, R. L.; Turtle, E. P.; Wood, C. A.; Stofan, E. R.

2015-12-01

Driven by an expansive atmosphere, Titan's lakes, seas and accompanied hydrological cycle hold vast amounts of information regarding the history and evolution of Titan. To understand these features, we constructed a geomorphologic map of Titan's polar terrains using a combination of the Cassini SAR, ISS, VIMS, and topographic datasets. In combining SAR, ISS, and VIMS imagery with topographic data, our geomorphic map reveals a stratigraphic sequence from which we infer formation processes. In mapping both the South and North poles with the same morphologic units, we conclude that processes that dominated the North Pole also operated in the South. Large seas, which are currently methane/ethane filled in the North and dry in the South, characterize both poles. The current day dichotomy may result only from differing initial conditions. Regions removed from the mare are dominated by smooth, undulating plains, bounded by moderately dissected uplands that are discretized into observable drainage basins. These plains contain the highest density of filled and empty lake depressions, which appear morphologically distinct from the larger mare. The thicknesses of these undulating plains are retrieved from the depths of the embedded empty depressions that are up to 800 m deep. The development of such large deposits and the surrounding hillslopes can be explained by the presence of previously vast polar oceans. Larger liquid bodies would have allowed for a sustained accumulation of soluble and insoluble sediments from Titan's lower latitudes. Two plausible evolutionary scenarios include seas that were slightly larger, followed by tectonic uplift, or oceans that were much larger, that have since lost most of their volume over time to methane photolysis. In either scenario, thick sedimentary deposits of soluble materials are required to have been emplaced prior to the formation of the small lake depressions.

How does landscape structure influence catchment transit time across different geomorphic provinces?

USGS Publications Warehouse

Tetzlaff, D.; Seibert, J.; McGuire, K.J.; Laudon, H.; Burns, Douglas A.; Dunn, S.M.; Soulsby, C.

2009-01-01

Despite an increasing number of empirical investigations of catchment transit times (TTs), virtually all are based on individual catchments and there are few attempts to synthesize understanding across different geographical regions. Uniquely, this paper examines data from 55 catchments in five geomorphic provinces in northern temperate regions (Scotland, United States of America and Sweden). The objective is to understand how the role of catchment topography as a control on the TTs differs in contrasting geographical settings. Catchment inverse transit time proxies (ITTPs) were inferred by a simple metric of isotopic tracer damping, using the ratio of standard deviation of ??18O in streamwater to the standard deviation of ??18O in precipitation. Quantitative landscape analysis was undertaken to characterize the catchments according to hydrologically relevant topographic indices that could be readily determined from a digital terrain model (DTM). The nature of topographic controls on transit times varied markedly in different geomorphic regions. In steeper montane regions, there are stronger gravitational influences on hydraulic gradients and TTs tend to be lower in the steepest catchments. In provinces where terrain is more subdued, direct topographic control weakened; in particular, where flatter areas with less permeable soils give rise to overland flow and lower TTs. The steeper slopes within this flatter terrain appear to have a greater coverage of freely draining soils, which increase sub-surface flow, therefore increasing TTs. Quantitative landscape analysis proved a useful tool for intercatchment comparison. However, the critical influence of sub-surface permeability and connectivity may limit the transferability of predictive tools of hydrological function based on topographic parameters alone. Copyright ?? 2009 John Wiley & Sons, Ltd.

Synthetic river valleys: Creating prescribed topography for form-process inquiry and river rehabilitation design

NASA Astrophysics Data System (ADS)

Brown, R. A.; Pasternack, G. B.; Wallender, W. W.

2014-06-01

The synthesis of artificial landforms is complementary to geomorphic analysis because it affords a reflection on both the characteristics and intrinsic formative processes of real world conditions. Moreover, the applied terminus of geomorphic theory is commonly manifested in the engineering and rehabilitation of riverine landforms where the goal is to create specific processes associated with specific morphology. To date, the synthesis of river topography has been explored outside of geomorphology through artistic renderings, computer science applications, and river rehabilitation design; while within geomorphology it has been explored using morphodynamic modeling, such as one-dimensional simulation of river reach profiles, two-dimensional simulation of river networks, and three-dimensional simulation of subreach scale river morphology. To date, no approach allows geomorphologists, engineers, or river rehabilitation practitioners to create landforms of prescribed conditions. In this paper a method for creating topography of synthetic river valleys is introduced that utilizes a theoretical framework that draws from fluvial geomorphology, computer science, and geometric modeling. Such a method would be valuable to geomorphologists in understanding form-process linkages as well as to engineers and river rehabilitation practitioners in developing design surfaces that can be rapidly iterated. The method introduced herein relies on the discretization of river valley topography into geometric elements associated with overlapping and orthogonal two-dimensional planes such as the planform, profile, and cross section that are represented by mathematical functions, termed geometric element equations. Topographic surfaces can be parameterized independently or dependently using a geomorphic covariance structure between the spatial series of geometric element equations. To illustrate the approach and overall model flexibility examples are provided that are associated with mountain, lowland, and hybrid synthetic river valleys. To conclude, recommended advances such as multithread channels are discussed along with potential applications.

Coastal wetlands, sea level, and the dimensions of geomorphic resilience

NASA Astrophysics Data System (ADS)

Phillips, Jonathan D.

2018-03-01

Geomorphic system resilience is often perceived as an intrinsic property of system structure and interactions but is also related to idiosyncratic place and history factors. The importance of geographical and historical circumstances makes it difficult to generate categorical statements about geomorphic resilience. However, network-based analyses of system structure can be used to determine the dynamical stability (= resilience) based on generally applicable relationships and to determine scenarios of stability or instability. These provide guidelines for assessing place and history factors to assess resilience. A model of coastal wetlands is analyzed, based on interactions among relative sea level, wetland surface elevation, hydroperiod, vegetation, and sedimentation. The system is generally (but not always) dynamically unstable and non-resilient. Because of gradients of environmental factors and patchy distributions of microtopography and vegetation, a coastal wetland landscape may have extensive local variations in stability/resilience and in the key relationships that trigger instabilities. This is illustrated by a case study where dynamically unstable fragmentation is found in two nearby coastal wetlands in North Carolina's Neuse River estuary-Otter Creek Mouth and Anderson Creek. Neither is keeping pace with relative sea level rise, and both show unstable state transitions within the wetland system; but locally stable relationships exist within the wetland systems.

Transfer of fallout radionuclides derived from Fukushima NPP accident: 1 year study on transfer of radionuclides through geomorphic processes

NASA Astrophysics Data System (ADS)

Onda, Y.; Kato, H.; Fukushima, T.; Wakahara, T.; Kita, K.; Takahashi, Y.; Sakaguchi, A.; Tanaka, K.; Yamashiki, Y.; Yoshida, N.

2012-12-01

After the Fukushima Daiichi Nuclear Power Plant acciden, fallout radionuclides on the ground surface will transfer through geomorphic processes. Therefore, in order to estimate future changes in radionuclide deposition, migration process of radionuclides in forests, soils, ground water, rivers, and entrainment from trees and soils should be confirmed. We (FMWSE group) was funded by MEXT, Japanese government, and 1 year following monitoring has been conducted about 1 year. 1 Migration study of radionuclides in natural environment including forests and rivers 1) Study on depth distribution of radiocaesium in soils within forests, fields, and grassland. 2) Confirmation of radionuclide distribution and investigation on migration in forests. 3) Study on radionuclide migration due to soil erosion under different land use. 4) Measurement of radionuclides entrained from natural environment including forests and soils. 2 Migration study of radionuclides through hydrological cycle such as soil water, rivers, lakes and ponds, ground water. 1) Investigation on radionuclide migration through soil water, ground water, stream water, spring water under different land use. 2) Study on paddy-to-river transfer of radionuclides through suspended sediment. 3) Study on river-to-ocean transfer of radionuclides via suspended sediment. 4) Confirmation of radionuclide deposition in ponds and reservoirs. We will present how and where the fallout radionulides transfter through geomorphic processes.

Unravelling recent environmental change in a lowland river valley, eastern Ireland: geoarchaeological applications

NASA Astrophysics Data System (ADS)

Foster, Gez; Turner, Jonathan

2010-05-01

This paper reports the preliminary findings of an Irish Heritage Council INSTAR funded research project on the geoarchaeology and fluvial geomorphology of the lower River Boyne valley, eastern Ireland. The nature and evolution of the contemporary Boyne floodplain at Dunmoe, Co. Meath (53° 40' 22.8" N, 6° 37' 54.7" W) has been investigated using a multi-technique approach combining field and terrestrial LiDAR-based geomorphological mapping, radiocarbon dating of channel migration activity, electrical resistivity tomography surveys of sub-surface topography and high-resolution X-ray and XRF geochemical characterisation of fine-grained sediment fill sequences. All of these lines of evidence support a tripartite sub-division of the floodplain. Valley marginal floodplain Zone 1 is characterised by a colluvial sediment fill which has buried an irregular ditch-basin-platform surface containing recent archaeological material. Subtle variations in mapped elevation suggest that the buried surface may represent the site of an abandoned river-side complex, possibly a small docking area or port. Geomorphological field relationships suggest that the possible archaeological site was connected to a former bank line position of the main River Boyne (floodplain Zone 2) via a small canal. Radiocarbon dating of Zone 2 channel gravels suggests that the channel associated with this bank position was abandoned some time before 1490-1610 AD. Subsequent vertical and lateral channel migration, the onset of which has been radiocarbon dated to the 17th or 18th century AD, led to the development of the lowest and most recent floodplain surface (Zone 3). The sedimentology and geochemistry of the Zone 2 and 3 fluvial sediment sequences suggests that recent centuries have involved an increase in fluvial flood risk, evidenced by the burial of alluvial soils by bedded, shell-rich sands. A more complete understanding of the timing and environmental drivers of increasing flood risk is anticipated from ongoing radionuclide (Pb-210 and Cs-137) and pollen analysis of the fluvial sediment sequences. However, based on the established chronology and geomorphic field relationships, it is plausible that the archaeological complex represents a late medieval site linked to Dunmoe Castle (14th to 17th century AD), which overlooks the floodplain.

Geomorphic controls on fluvial carbon exports and emissions from upland swamps in eastern Australia.

PubMed

Cowley, Kirsten; Looman, Arun; Maher, Damien T; Fryirs, Kirstie

2018-03-15

Temperate Highland Peat Swamps on Sandstone (THPSS) are upland wetlands, similar to fens in the Northern Hemisphere and are found at the headwaters of low-order streams on the plateaus of Eastern Australia. They are classified as endangered ecological communities under State and National legislation. Previous works have identified particular geomorphic characteristics that are important to carbon storage in these low energy sediment accumulation zones. Changes in the geomorphic structure of THPSS, such as channelisation, may have profound implications for carbon storage. To assess the effect of channelisation on carbon budgets in these ecosystems it is essential to identify and quantify differences in carbon export, emissions and stocks of carbon of intact swamps and those that have become channelised. We undertook seasonal sampling of the perched swamp aquifers and surface waters of two intact swamps and two channelised fills in the Blue Mountains of New South Wales, Australia, to investigate differences in carbon exports and emissions between the two swamp types. We found that channelised fills' mean CO 2 emissions were almost four times higher than intact swamps with mean CH 4 emissions up to five times higher. Annual fluvial carbon exports for channelised fills were up to 18 times that of intact swamps. Channelised fill exports and emissions can represent up to 2% of the total swamp carbon stocks per annum which is 40 times higher than the intact swamps. This work clearly demonstrates that changes in geomorphic structure brought about by incision and channelisation results in profound changes to the carbon storage function of THPSS. Copyright © 2017 Elsevier B.V. All rights reserved.

Comprehensive Representation of Hydrologic and Geomorphic Process Coupling in Numerical Models: Internal Dynamics and Basin Evolution

NASA Astrophysics Data System (ADS)

Istanbulluoglu, E.; Vivoni, E. R.; Ivanov, V. Y.; Bras, R. L.

2005-12-01

Landscape morphology has an important control on the spatial and temporal organization of basin hydrologic response to climate forcing, affecting soil moisture redistribution as well as vegetation function. On the other hand, erosion, driven by hydrology and modulated by vegetation, produces landforms over geologic time scales that reflect characteristic signatures of the dominant land forming process. Responding to extreme climate events or anthropogenic disturbances of the land surface, infrequent but rapid forms of erosion (e.g., arroyo development, landsliding) can modify topography such that basin hydrology is significantly influenced. Despite significant advances in both hydrologic and geomorphic modeling over the past two decades, the dynamic interactions between basin hydrology, geomorphology and terrestrial ecology are not adequately captured in current model frameworks. In order to investigate hydrologic-geomorphic-ecologic interactions at the basin scale we present initial efforts in integrating the CHILD landscape evolution model (Tucker et al. 2001) with the tRIBS hydrology model (Ivanov et al. 2004), both developed in a common software environment. In this talk, we present preliminary results of the numerical modeling of the coupled evolution of basin hydro-geomorphic response and resulting landscape morphology in two sets of examples. First, we discuss the long-term evolution of both the hydrologic response and the resulting basin morphology from an initially uplifted plateau. In the second set of modeling experiments, we implement changes in climate and land-use to an existing topography and compare basin hydrologic response to the model results when landscape form is fixed (e.g. no coupling between hydrology and geomorphology). Model results stress the importance of internal basin dynamics, including runoff generation mechanisms and hydrologic states, in shaping hydrologic response as well as the importance of employing comprehensive conceptualizations of hydrology in modeling landscape evolution.

Understanding the Effects of Sea-Level Rise on Coastal Wetlands: The Human Dimension

NASA Astrophysics Data System (ADS)

Reed, Denise

2010-05-01

In the 21st century coastal systems are subject to the pressures of centuries of population growth and resource exploitation. In 2003, in the US approximately 153 million people (53 percent of the population) lived in coastal counties, an increase of 33 million people since 1980 and this is expected to increase by approximately 7 million by the year 2008. Eight of the world's top ten largest cities are located at the coast, 44 % of the world's population (more people than inhabited the entire globe in 1950) live within 150 km of the coast and in 2001 over half the world's population lived within 200 km of a coastline. . Increased population density at the coasts often brings pollution and habitat degradation - decreasing the value of many of the resources that initially attract the coastal development - and it also means the effect of sea-level rise on coastal geomorphic systems must be seen in the context of additional human pressures. For global sea-level debate centers on the magnitude and rate of the rise around most of the world; the exception being those areas still experiencing falling sea-levels due to isostatic rebound. Many coastal island states are clearly vulnerable. While the ‘lurid and misleading maps' of the 1980's used by many to indicate areas to be flooded by rising seas in the future, have been replaced by more considered discussion of the response of coastal dynamics to rising seas there is still considerable debate about the amount of sea-level rise shorelines will experience in the 21st century. For coastal wetlands four main sets of physical factors - fine sediment regime; tidal conditions; coastal configuration; and relative sea-level change - define the geomorphic context for coastal marsh development and survival during the 21st century. Each of these factors is influenced by changes in climate and human alterations to coastal and inshore environments. In turn changes in sediment dynamics are mediated by both physical forcing and biotic factors, and plant growth is an additional factor influencing the survival of more organic marshes. Salt marsh surfaces are frequently considered to be in an equilibrium relationship with local mean sea level but the projection of salt marsh sustainability under future climate scenarios is a complex issue and depends on: the relative importance of organic matter to marsh vertical development; the complexities governing organic matter accumulation during rising sea level; the importance of subsurface processes in determining surface elevation change; and the role of storm events and hydrologic changes in controlling sediment deposition, soil conditions and plant growth. The effects of global change, both climate and human induced, on coastal wetlands will be manifest differently among various geomorphic settings but their vulnerability to global change in the 21st century should be taken seriously by coastal managers and policy-makers alike.

A geomorphological seabed classification for the Weddell Sea, Antarctica

NASA Astrophysics Data System (ADS)

Jerosch, Kerstin; Kuhn, Gerhard; Krajnik, Ingo; Scharf, Frauke Katharina; Dorschel, Boris

2016-06-01

Sea floor morphology plays an important role in many scientific disciplines such as ecology, hydrology and sedimentology since geomorphic features can act as physical controls for e.g. species distribution, oceanographically flow-path estimations or sedimentation processes. In this study, we provide a terrain analysis of the Weddell Sea based on the 500 m × 500 m resolution bathymetry data provided by the mapping project IBCSO. Seventeen seabed classes are recognized at the sea floor based on a fine and broad scale Benthic Positioning Index calculation highlighting the diversity of the glacially carved shelf. Beside the morphology, slope, aspect, terrain rugosity and hillshade were calculated and supplied to the data archive PANGAEA. Applying zonal statistics to the geomorphic features identified unambiguously the shelf edge of the Weddell Sea with a width of 45-70 km and a mean depth of about 1200 m ranging from 270 m to 4300 m. A complex morphology of troughs, flat ridges, pinnacles, steep slopes, seamounts, outcrops, and narrow ridges, structures with approx. 5-7 km width, build an approx. 40-70 km long swath along the shelf edge. The study shows where scarps and depressions control the connection between shelf and abyssal and where high and low declination within the scarps e.g. occur. For evaluation purpose, 428 grain size samples were added to the seabed class map. The mean values of mud, sand and gravel of those samples falling into a single seabed class was calculated, respectively, and assigned to a sediment texture class according to a common sediment classification scheme.

EAARL Topography-Padre Island National Seashore

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

2007-01-01

This Web site contains 116 Lidar-derived bare earth topography maps and GIS files for Padre Island National Seashore-Texas. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Florida Integrated Science Center (FISC) St. Petersburg, Florida, the National Park Service (NPS) Gulf Coast Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

Tectonic and climatic significance of a late Eocene low-relief, high-level geomorphic surface, Colorado

NASA Technical Reports Server (NTRS)

Gregory, Kathryn M.; Chase, Clement G

1994-01-01

New paleobotanical data suggest that in the late Eocene the erosion surface which capped the Front Range, Colorado was 2.2-2.3 km in elevation, which is similar to the 2.5-km present elevation of surface remnants. This estimated elevation casts doubt on the conventional belief that the low-relief geomorphic surface was formed by lateral planation of streams to a base level not much higher than sea level and that the present deeply incised canyons must represent Neogene uplift of Colorado. Description of the surface, calculations of sediment volume, and isostatic balance and fluvial landsculpting models demonstrate that while the high elevation of the erosion surface was due to tectonic forces, its smoothness was mostly a result of climatic factors. A sediment balance calculated for the Front Range suggests that from 2 to 4 km of material were eroded by the late Eocene, consistent with fission track ages. This amount of erosion would remove a significant portionof the 7 km of Laramide upper crustal thickening. Isostatic modeling implies that the 2.2-3.3 km elevation was most likely created by lower crustal thickening during the Laramide. A numerical model of fluvial erosion and deposition suggests a way that a late Eocene surface could have formed at this high elevation without incision. A humid climate with a preponderance of small storm events will diffusively smooth topography and is a possible mechanism for formation oflow-relief, high-level surfaces. Paleoclimate models suggest a lack of large strom events in the late Eocene because of cool sea surface temperatures in the equatorial region. Return to a drier but stormier climate post-Eocene could have caused the incision of the surface by young canyons. By this interpretation, regional erosion surfaces may represent regional climatic rather than tectonic conditions.

Latest Quaternary rapid river incision across an inactive fold in the northern Chinese Tian Shan foreland

NASA Astrophysics Data System (ADS)

Lu, Honghua; Cheng, Lu; Wang, Zhen; Zhang, Tianqi; Lü, Yanwu; Zhao, Junxiang; Li, Youli; Zheng, Xiangmin

2018-01-01

This work focuses on the incision process over the Tuostai anticline, a fold of the proximal structure Belt I in the northern Chinese Tian Shan foreland, where the Sikeshu River has incised deeply into the alluvial gravels and the fold's underlying bedrock strata. Field investigation and geomorphic mapping define five terraces of the Sikeshu River (designated as T1 to T5 from oldest to youngest) preserved within the Tuostai anticline. 10Be surface exposure dating and optically stimulated luminescence dating constrain stabilization of the highest three terrace surfaces at about 80 ka (T1), 16 ka (T2), and 15 ka (T3), respectively. Around 16 ka, the calculated river incision rates significantly increase from <2 mm/yr to >6 mm/yr. Undeformed longitudinal profiles of terraces T2, T3 and T4 over the Tuostai anticline suggest that this structure may have been tectonically inactive since stabilization of these three terraces. We thus think that the observed rapid river incision over the Tuostai anticline has not been largely forced by tectonic uplift. Instead, the progressively warmer and wetter palaeoclimatic condition within the Tian Shan range and its surrounding area during the period of ∼20-10 ka may have enhanced river incision across the Tuostai anticline. A reduced sediment/water ratio might have lowered the gradient of the Sikeshu River.

A multi-resolution analysis of lidar-DTMs to identify geomorphic processes from characteristic topographic length scales

NASA Astrophysics Data System (ADS)

Sangireddy, H.; Passalacqua, P.; Stark, C. P.

2013-12-01

Characteristic length scales are often present in topography, and they reflect the driving geomorphic processes. The wide availability of high resolution lidar Digital Terrain Models (DTMs) allows us to measure such characteristic scales, but new methods of topographic analysis are needed in order to do so. Here, we explore how transitions in probability distributions (pdfs) of topographic variables such as (log(area/slope)), defined as topoindex by Beven and Kirkby[1979], can be measured by Multi-Resolution Analysis (MRA) of lidar DTMs [Stark and Stark, 2001; Sangireddy et al.,2012] and used to infer dominant geomorphic processes such as non-linear diffusion and critical shear. We show this correlation between dominant geomorphic processes to characteristic length scales by comparing results from a landscape evolution model to natural landscapes. The landscape evolution model MARSSIM Howard[1994] includes components for modeling rock weathering, mass wasting by non-linear creep, detachment-limited channel erosion, and bedload sediment transport. We use MARSSIM to simulate steady state landscapes for a range of hillslope diffusivity and critical shear stresses. Using the MRA approach, we estimate modal values and inter-quartile ranges of slope, curvature, and topoindex as a function of resolution. We also construct pdfs at each resolution and identify and extract characteristic scale breaks. Following the approach of Tucker et al.,[2001], we measure the average length to channel from ridges, within the GeoNet framework developed by Passalacqua et al.,[2010] and compute pdfs for hillslope lengths at each scale defined in the MRA. We compare the hillslope diffusivity used in MARSSIM against inter-quartile ranges of topoindex and hillslope length scales, and observe power law relationships between the compared variables for simulated landscapes at steady state. We plot similar measures for natural landscapes and are able to qualitatively infer the dominant geomorphic processes. Also, we explore the variability in hillslope length scales as a function of hillslope diffusivity coefficients and critical shear stress in natural landscapes and show that we can infer signatures of dominant geomorphic processes by analyzing characteristic topographic length scales present in topography. References: Beven, K. and Kirkby, M. J.: A physically based variable contributing area model of basin hydrology, Hydrol. Sci. Bull., 24, 43-69, 1979 Howard, A. D. (1994). A detachment-limited model of drainage basin evolution.Water resources research, 30(7), 2261-2285. Passalacqua, P., Do Trung, T., Foufoula Georgiou, E., Sapiro, G., & Dietrich, W. E. (2010). A geometric framework for channel network extraction from lidar: Nonlinear diffusion and geodesic paths. Journal of Geophysical. Research: Earth Surface (2003-2012), 115(F1). Sangireddy, H., Passalacqua, P., Stark, C.P.(2012). Multi-resolution estimation of lidar-DTM surface flow metrics to identify characteristic topographic length scales, EP13C-0859: AGU Fall meeting 2012. Stark, C. P., & Stark, G. J. (2001). A channelization model of landscape evolution. American Journal of Science, 301(4-5), 486-512. Tucker, G. E., Catani, F., Rinaldo, A., & Bras, R. L. (2001). Statistical analysis of drainage density from digital terrain data. Geomorphology, 36(3), 187-202.

Solar radiation as a global driver of hillslope asymmetry: Insights from an ecogeomorphic landscape evolution model

NASA Astrophysics Data System (ADS)

Yetemen, Omer; Istanbulluoglu, Erkan; Duvall, Alison R.

2015-12-01

Observations at the field, catchment, and continental scales across a range of arid and semiarid climates and latitudes reveal aspect-controlled patterns in soil properties, vegetation types, ecohydrologic fluxes, and hillslope morphology. Although the global distribution of solar radiation on earth's surface and its implications on vegetation dynamics are well documented, we know little about how variation of solar radiation across latitudes influence landscape evolution and resulting geomorphic difference. Here, we used a landscape evolution model that couples the continuity equations for water, sediment, and aboveground vegetation biomass at each model element in order to explore the controls of latitude and mean annual precipitation (MAP) on the development of hillslope asymmetry (HA). In our model, asymmetric hillslopes emerged from the competition between soil creep and vegetation-modulated fluvial transport, driven by spatial distribution of solar radiation. Latitude was a primary driver of HA because of its effects on the global distribution of solar radiation. In the Northern Hemisphere, north-facing slopes (NFS), which support more vegetation cover and have lower transport efficiency, get steeper toward the North Pole while south-facing slopes (SFS) get gentler. In the Southern Hemisphere, the patterns are reversed and SFS get steeper toward the South Pole. For any given latitude, MAP is found to have minor control on HA. Our results underscore the potential influence of solar radiation as a global control on the development of asymmetric hillslopes in fluvial landscapes.

Geologic Map of MTM 35337, 40337, and 45337 Quadrangles, Deuteronilus Mensae Region of Mars

USGS Publications Warehouse

Chuang, Frank C.; Crown, David A.

2009-01-01

Deuteronilus Mensae, first defined as an albedo feature at lat 35.0 deg N., long 5.0 deg E., by U.S. Geological Survey (USGS) and International Astronomical Union (IAU) nomenclature, is a gradational zone along the dichotomy boundary in the northern mid-latitudes of Mars. The boundary in this location includes the transition from the rugged cratered highlands of Arabia Terra to the northern lowland plains of Acidalia Planitia. Within Deuteronilus Mensae, polygonal mesas are prominent along with features diagnostic of Martian fretted terrain, including lobate debris aprons, lineated valley fill, and concentric crater fill. Lobate debris aprons, as well as the valley and crater fill deposits, are geomorphic indicators of ground ice, and their concentration in Deuteronilus Mensae is of great interest because of their potential association with Martian climate change. The paucity of impact craters on the surfaces of debris aprons and the presence of ice-cemented mantle material imply young (for example, Amazonian) surface ages that are consistent with recent climate change in this region of Mars. North of Deuteronilus Mensae are the northern lowlands, a potential depositional sink that may have had large standing bodies of water or an ocean in the past. The northern lowlands have elevations that are several kilometers below the ancient cratered highlands with significantly younger surface ages. The morphologic and topographic characteristics of the Deuteronilus Mensae region record a diverse geologic history, including significant modification of the ancient highland plateau and resurfacing of low-lying regions. Previous studies of this region have interpreted a complex array of geologic processes, including eolian, fluvial and glacial activity, coastal erosion, marine deposition, mass wasting, tectonic faulting, effusive volcanism, and hydrovolcanism. The origin and age of the Martian crustal dichotomy boundary are fundamental questions that remain unresolved at the present time. Several scenarios for its formation, including single and multiple large impact events, have been proposed and debated in the literature. Endogenic processes whereby crust is thinned by internal mantle convection and tectonic processes have also been proposed. Planetary accretion models and isotopic data from Martian meteorites suggest that the crust formed very early in Martian history. Using populations of quasi-circular depressions extracted from the topography of Mars, other studies suggest that the age difference between the highlands and lowlands could be ~100 m.y.. Furthermore, understanding the origin and age of the dichotomy boundary has been made more complicated due to significant erosion and deposition that have modified the boundary and its adjacent regions. The resulting diversity of terrains and features is likely a combined result of ancient and recent events. Detailed geologic analyses of dichotomy boundary zones are important for understanding the spatial and temporal variations in highland evolution. This information, and comparisons to other highland regions, can help elucidate the scale of potential environmental changes. Previous geomorphic and geologic mapping investigations of the Deuteronilus Mensae region have been completed at local to global scales. The regional geology was first mapped by Lucchitta (1978) at 1:5,000,000 scale using Mariner 9 data. This study concluded that high crater flux early in Martian history formed overlapping craters and basins that were later filled by voluminous lava flows that buried the impacted surface, creating the highlands. After this period of heavy bombardment, fluvial erosion of the highlands formed the canyons and valleys, followed by dissection that created the small mesas and buttes, and later, formation of the steep escarpment marking the present-day northern highland margin. After valley dissection, mass wasting and eolian processes caused lateral retreat of mesas and buttes

Distributions of Benthic Foraminifera in the Salisbury Embayment before and after the PETM Onset

NASA Astrophysics Data System (ADS)

Range, M. M.; Robinson, M. M.

2017-12-01

Abrupt climatic perturbations associated with the onset of the Paleocene-Eocene Thermal Maximum (PETM) caused major disruptions to the shallow shelf ecology along the U.S. Atlantic Coastal Plain. Several studies examine the changes in benthic foraminiferal assemblages across the PETM in neritic sediments in New Jersey, Maryland, and Virginia and describe a hydrological and sedimentological paradigm shift that marks the Paleocene-Eocene boundary. In the Salisbury Embayment, a flexural low between the South Jersey High and the Norfolk Arch, this shift is seen in the transition between the upper Paleocene Aquia Formation and the lower Eocene Marlboro Clay. Here we map the abundance of seven benthic foraminifera species from five sites within the Salisbury Embayment from both the uppermost Aquia Formation and the lowermost Marlboro Clay. In addition to the benthic foraminiferal turnover at the PETM onset, we show a geographic distribution of species that highlights a past latitudinal biogeographic zonation not unlike what is found on the modern shelf in this region. Sites document a change in the abundance of species between the late Paleocene and early Eocene, showing a decrease in biodiversity of benthic species along the U.S. Atlantic Coast. Spatial extent of the different species also changed across the Paleocene-Eocene boundary. On the modern Atlantic shelf, a biogeographic zonation is due to the path of the Gulf Stream marking a boundary between relatively cold sea-surface temperatures to the north and warmer temperatures to the south, guided by the geomorphic expression of the mid-Atlantic coastline. During the Paleocene-Eocene transition, we suspect a similar boundary likely existed between the New Jersey sites and the Maryland and Virginia sites. We speculate that with the addition of more assemblage data, we will be able to partially reconstruct the geomorphic expression of the PETM coastline and/or the path of major coastal ocean currents.

The Individual and Additive Effects of Vegetation Encroachment and Hydrologic Alteration on Sediment Connectivity in Grand Canyon

NASA Astrophysics Data System (ADS)

Kasprak, A.; Buscombe, D.; Caster, J.; Grams, P. E.; Sankey, J. B.

2016-12-01

Sediment connectivity is a vital component of the eco-geomorphic function of river systems, and the pathways of sediment transfer in river valleys often shift in response to channel disturbance and development. Along the Colorado River downstream of Glen Canyon Dam (completed in 1963), flow alteration for hydropower generation has increased baseflows while reducing the magnitude of regularly-occurring floods, and vegetation has subsequently colonized many channel-margin surfaces. In this dryland, canyon-bound river system, aeolian transport has historically been a vital component of sediment connectivity, yet the relative roles of altered hydrology and vegetation on the extent of sand available for windblown transport are unknown. Here we use a fusion of high-resolution spatial datasets including channel bathymetry and bed classification derived from single- and multibeam echosounding and total station surveys, exposed sand mapping and vegetation classification from multispectral imagery, in concert with a 94 year discharge record and one-dimensional hydraulic modeling to quantify changes in sand availability along a 48 km reach of the Colorado River. We find that hydrologic alteration alone has reduced areal sand availability by approximately 15% when comparing the pre- and post-dam flow records, while vegetation encroachment has had an even greater effect. More than half of the total sand area in the study reach is located at low flow stages below 226 m3/s, meaning that small reductions in baseflow discharge have the potential to expose large quantities of sand, and we subsequently explore the relative effect of alternative flow regimes on sand exposure during the postdam period. The ability to quantify and explore the efficacy of river management strategies on large-scale sediment connectivity has the potential to inform eco-geomorphic management of the Colorado River in Grand Canyon and other regulated rivers worldwide.

New England salt marsh pools: A quantitative analysis of geomorphic and geographic features

USGS Publications Warehouse

Adamowicz, S.C.; Roman, C.T.

2005-01-01

New England salt marsh pools provide important wildlife habitat and are the object of on-going salt marsh restoration projects; however, they have not been quantified in terms of their basic geomorphic and geographic traits. An examination of 32 ditched and unditched salt marshes from the Connecticut shore of Long Island Sound to southern Maine, USA, revealed that pools from ditched and unditched marshes had similar average sizes of about 200 m2, averaged 29 cm in depth, and were located about 11 m from the nearest tidal flow. Unditched marshes had 3 times the density (13 pools/ha), 2.5 times the pool coverage (83 m pool/km transect), and 4 times the total pool surface area per hectare (913 m2 pool/ha salt marsh) of ditched sites. Linear regression analysis demonstrated that an increasing density of ditches (m ditch/ha salt marsh) was negatively correlated with pool density and total pool surface area per hectare. Creek density was positively correlated with these variables. Thus, it was not the mere presence of drainage channels that were associated with low numbers of pools, but their type (ditch versus creek) and abundance. Tidal range was not correlated with pool density or total pool surface area, while marsh latitude had only a weak relationship to total pool surface area per hectare. Pools should be incorporated into salt marsh restoration planning, and the parameters quantified here may be used as initial design targets.

Volatile reservoirs below the surface of the Elysium region of Mars: Geomorphic evidence

NASA Technical Reports Server (NTRS)

Christiansen, Eric H.; Hopler, Jennifer A.

1987-01-01

The Elysium volcanic province contains a variety of geomorphic evidence for the existence of large volatile reservoirs of subsurface volatiles. Study of these landforms yields insight into the distribution and size of these reservoirs and how they interact with the surface environment and will ultimately place constraints on the geometry, constitution, origin, time of formation, and temporal evolution of these important components of the Martian crust. Three principal types of landforms appear to be related to subsurface volatile reservoirs in the Elysium region of Mars: small outflow channels; large lahars; and vast expanses of knobby terranes around the margins of the Elysium dome. The evidence provided by these landforms is internally consistent with the presence of a large relatively shallow volatile reservoir in the Elysium region. If the geologic features described are reliable indicators of subsurface volatiles, they imply that: volatile reservoirs lie relatively close to the surface and underlie millions of sq km in this region; there is no apparent latitudinal variation in the depth or thickness of the volatile reservoirs; the precursors of the knobby terranes are or were important volatile reservoirs; volatiles may be lost in a variety of ways from these reservoirs; and volatiles were incorporated in an easily eroded surficial deposit in the middle history of Mars. The ultimate origin of water in this reservoir is uncertain. A model to explain the preferential entrapment of volatiles into the region's surface materials may be required.

A conceptual connectivity framework for understanding geomorphic change in human-impacted fluvial systems

NASA Astrophysics Data System (ADS)

Poeppl, Ronald E.; Keesstra, Saskia D.; Maroulis, Jerry

2017-01-01

Human-induced landscape change is difficult to predict due to the complexity inherent in both geomorphic and social systems as well as due to the coupling relationships between them. To better understand system complexity and system response to changing inputs, "connectivity thinking" has become an important recent paradigm within various disciplines including ecology, hydrology and geomorphology. With the presented conceptual connectivity framework on geomorphic change in human-impacted fluvial systems a cautionary note is flagged regarding the need (i) to include and to systematically conceptualise the role of different types of human agency in altering connectivity relationships in geomorphic systems and (ii) to integrate notions of human-environment interactions to connectivity concepts in geomorphology to better explain causes and trajectories of landscape change. Geomorphic response of fluvial systems to human disturbance is shown to be determined by system-specific boundary conditions (incl. system history, related legacy effects and lag times), vegetation dynamics and human-induced functional relationships (i.e. feedback mechanisms) between the different spatial dimensions of connectivity. It is further demonstrated how changes in social systems can trigger a process-response feedback loop between social and geomorphic systems that further governs the trajectory of landscape change in coupled human-geomorphic systems.

Establishing a Geologic Baseline Of Cape Canaveral's Natural Landscape: Black Point Drive

NASA Technical Reports Server (NTRS)

Parkinson, Randall W.

2001-01-01

The goal of this project is to identify the process responsible for the formation of geomorphic features in the Black Point Drive area of Merritt Island National Wildlife Refuge/Kennedy Space Center (MINWR/KSC), northwest Cape Canaveral. This study confirms the principal landscape components (geomorphology) of Black Point Drive reflect interaction between surficial sediments deposited in association with late-Quaternary sea-level highstands and the chemical evolution of late-Cenozoic subsurface limestone formations. The Black Point Drive landscape consists of an undulatory mesic terrain which dips westward into myriad circular and channel-like depression marshes and lakes. This geomorphic gradient may reflect: (1) spatial distinctions in the elevation, character or age of buried (pre-Miocene) limestone formations, (2) dissolution history of late-Quaternary coquina and/or (3) thickness of unconsolidated surface sediment. More detailed evaluation of subsurface data will be necessary before this uncertainty can be resolved.

Altered hydrologic and geomorphic processes and bottomland hardwood plant communities of the lower White River Basin

USGS Publications Warehouse

King, Sammy L.; Keim, Richard F.; Hupp, Cliff R.; Edwards, Brandon L.; Kroschel, Whitney A.; Johnson, Erin L.; Cochran, J. Wesley

2016-09-12

Determine stand establishment patterns of bottomland hardwoods within selected plant communities along three sections of the floodplain. This study provides baseline information on the current geomorphic and hydrologic conditions of the river and can assist in the interpretation of forest responses to past hydrologic and geomorphic processes. Understanding the implications for floodplain forests of geomorphic adjustment in the Lower Mississippi Alluvial Valley is key to managing the region’s valuable resources for a sustainable future.

Pedologic and geomorphic impacts of a tornado blowdown event in a mixed pine-hardwood forest

Treesearch

Jonathan D. Phillips; Daniel A. Marion; Alice V. Turkington

2008-01-01

Biomechanical effects of trees on soils and surface processes may be extensive in forest environments. Two blowdown sites caused by a November 2005 tornado in the Ouachita National Forest, Arkansas allowed a case study examination of bioturbation associated with a specific forest blowdown event, as well as detailed examination of relationships between tree root systems...

Terrestrial laser scanning observations of geomorphic changes and varying lava lake levels at Erebus volcano, Antarctica

NASA Astrophysics Data System (ADS)

Jones, Laura K.; Kyle, Philip R.; Oppenheimer, Clive; Frechette, Jedediah D.; Okal, Marianne H.

2015-03-01

A Terrestrial Laser Scanning (TLS) instrument was used to image the topography of the Main Crater at Erebus volcano each December in 2008, 2009, and 2010. Our high-spatial resolution TLS scans provide unique insights into annual and decadal scale geomorphic evolution of the summit area when integrated with comparable data collected by an airborne instrument in 2001. We observe both a pattern of subsidence within the Inner Crater of the volcano and an ~ 3 m per-year drop in the lava lake level over the same time period that are suggestive of decreasing overpressure in an underlying magma reservoir. We also scanned the active phonolite lava lake hosted within the Inner Crater, and recorded rapid cyclic fluctuations in the level of the lake. These were sporadically interrupted by minor explosions by bursting gas bubbles at the lake surface. The TLS data permit calculation of lake level rise and fall speeds and associated rates of volumetric change within the lake. These new observations, when considered with prior determinations of rates of lake surface motion and gas output, are indicative of unsteady magma flow in the conduit and its associated variability in gas volume fraction.

Monitoring morphological changes in an arid zone by spaceborne images and aerial photography between 1945 - 2009; the Yamin Plateau, Israel

NASA Astrophysics Data System (ADS)

Hetz, Guy; Blumberg, Dan; Avraham, Dody; Cohen, Hai

2010-05-01

This research focuses on a geomorphic mapping of the Yamin Plateau in southern Israel which is part of the Yamin-Rotem Syncline and covers about 200 km2. This area has been restricted since the 1950s and therefore, provides a unique opportunity to study undisturbed geomorphic processes. Nowadays, the national nuclear waste depository is located in this area accepting waste from industrial factories, research institutes and hospitals. This is the main reason why environmental processes are of major interest in terms of landform changes in space and time. The exposed geology section of the Yamin Plateau mostly consists of the Miocene Hazeva Group where sedimentary processes started 20 million years ago and continued for 12-14 million years. Two formations of the Miocene Hazeva Group appear in the study area Zefa and Rotem. The compositions of these two formations are similar and sometimes defined as "the main sand body" in the Hazeva Group. The restriction of the area stopped the grazing and let the development of a biological soil crust on the surface. The research objective was to document and characterize landform changes from 1945 until 2009 within the Yamin Plateau based on spaceborne images and aerial photography. All the parameters we extracted in the laboratory were validated with field measurements. A combination of the spaceborne images, aerial photography and field measurements leads us to the following conclusions: The research results show that soil stabilization processes took place earlier than the area closure. Inspite of decreasing precipitation tendencies as measured during the last 50 years in Yamin Plateau, the vegetation cover increased from 55% in 1945 to 67% in 2009. The main reason for this is the area closure and reduction in grazing along with developing of vegetation and biological soil crusts. Field studies and image processing of aerial photographs and recent QuickBird images alongside grain-size distribution show that in the past there were active zibar morphologies in the region. The most frequent grain-size of 350 μm supports this. Although the current geology map of the Yamin Plateau is characterized by sand soil texture, nowadays the study area surface contains 50% of clay minerals, which were probably trapped by soil crusts during dust storms. A grain size analysis shows the dominance of medium-coarse sand (350 μm) that partially mantle the Yamin Plateau surface. Aeolian activity that took place in the past and was concentrated in the southern and eastern parts of the plateau and included linear zibars. We also present a new index, the Clay Crust Index (CCI) that includes the combination of the Crust Index and the 7-th band of the Landsat TM that covers the clay absorption range. The idea behind this combination is based on trapping of clays by biological soil crusts which deepens the absorption feature in the spectrum of 7-th band of the Landsat TM. From 1945 to 2004 there were no evidence that indicate aeolian nor fluvial activities. Yet, a single extreme rain event that took place in 29 October 2004 caused the largest landform changes in the past 60 years. The runoff widened in the eastern channel streams. To summarize, the study area's closure in the late 1950's had contributed to the decrease of aeolian processes. The fluvial processes are very limited, yet, when there is an unusually large rainstorm event there is a risk of undermining and extreme erosion processes, especially when the surface is covered by soil crusts and clay.

Landslide Susceptibility Index Determination Using Aritificial Neural Network

NASA Astrophysics Data System (ADS)

Kawabata, D.; Bandibas, J.; Urai, M.

2004-12-01

The occurrence of landslide is the result of the interaction of complex and diverse environmental factors. The geomorphic features, rock types and geologic structure are especially important base factors of the landslide occurrence. Generating landslide susceptibility index by defining the relationship between landslide occurrence and that base factors using conventional mathematical and statistical methods is very difficult and inaccurate. This study focuses on generating landslide susceptibility index using artificial neural networks in Southern Japanese Alps. The training data are geomorphic (e.g. altitude, slope and aspect) and geologic parameters (e.g. rock type, distance from geologic boundary and geologic dip-strike angle) and landslides. Artificial neural network structure and training scheme are formulated to generate the index. Data from areas with and without landslide occurrences are used to train the network. The network is trained to output 1 when the input data are from areas with landslides and 0 when no landslide occurred. The trained network generates an output ranging from 0 to 1 reflecting the possibility of landslide occurrence based on the inputted data. Output values nearer to 1 means higher possibility of landslide occurrence. The artificial neural network model is incorporated into the GIS software to generate a landslide susceptibility map.

Pedological and geological relationships with soil lichen and moss distribution in the eastern Mojave Desert, CA, USA

USGS Publications Warehouse

Belnap, Jayne; Miller, David M.; Bedford, David R.; Phillips, Susan L.

2014-01-01

Biological soil crusts (biocrusts) are ubiquitous in drylands globally. Lichens and mosses are essential biocrust components and provide a variety of ecosystem services, making their conservation and management of interest. Accordingly, understanding what factors are correlated with their distribution is important to land managers. We hypothesized that cover would be related to geologic and pedologic factors. We sampled 32 sites throughout the eastern Mojave Desert, stratifying by parent material and the age of the geomorphic surfaces. The cover of lichens and mosses on ‘available ground’ (L + Mav; available ground excludes ground covered by rocks or plant stems) was higher on limestone and quartzite-derived soils than granite-derived soils. Cover was also higher on moderately younger-aged geomorphic surfaces (Qya2, Qya3, Qya4) and cutbanks than on very young (Qya1), older-aged surfaces (Qia1, Qia2), or soils associated with coppice mounds or animal burrowing under Larrea tridentata. When all sites and parent materials were combined, soil texture was the most important factor predicting the occurrence of L + Mav, with cover positively associated with higher silt, very fine sand, and fine sand fractions and negatively associated with the very coarse sand fraction. When parent materials were examined separately, nutrients such as available potassium, iron, and calcium became the most important predictors of L + Mav cover.

Columbia River Estuary ecosystem classification—Concept and application

USGS Publications Warehouse

Simenstad, Charles A.; Burke, Jennifer L.; O'Connor, Jim E.; Cannon, Charles; Heatwole, Danelle W.; Ramirez, Mary F.; Waite, Ian R.; Counihan, Timothy D.; Jones, Krista L.

2011-01-01

This document describes the concept, organization, and application of a hierarchical ecosystem classification that integrates saline and tidal freshwater reaches of estuaries in order to characterize the ecosystems of large flood plain rivers that are strongly influenced by riverine and estuarine hydrology. We illustrate the classification by applying it to the Columbia River estuary (Oregon-Washington, USA), a system that extends about 233 river kilometers (rkm) inland from the Pacific Ocean. More than three-quarters of this length is tidal freshwater. The Columbia River Estuary Ecosystem Classification ("Classification") is based on six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. We define and map Levels 1-3 for the entire Columbia River estuary with existing geospatial datasets, and provide examples of Levels 4-6 for one hydrogeomorphic reach. In particular, three levels of the Classification capture the scales and categories of ecosystem structure and processes that are most tractable to estuarine research, monitoring, and management. These three levels are the (1) eight hydrogeomorphic reaches that embody the formative geologic and tectonic processes that created the existing estuarine landscape and encompass the influence of the resulting physiography on interactions between fluvial and tidal hydrology and geomorphology across 230 kilometers (km) of estuary, (2) more than 15 ecosystem complexes composed of broad landforms created predominantly by geologic processes during the Holocene, and (3) more than 25 geomorphic catenae embedded within ecosystem complexes that represent distinct geomorphic landforms, structures, ecosystems, and habitats, and components of the estuarine landscape most likely to change over short time periods.

The Influence of Landslides on Channel Flood Response: A Case Study from the Colorado Front Range

NASA Astrophysics Data System (ADS)

Bennett, G. L.; Ryan, S. E.; Sholtes, J.; Rathburn, S. L.

2016-12-01

Studies have identified the role of thresholds and gradients in stream power in inducing geomorphic change during floods. At much longer time scales, empirical and modeling studies suggest the role of landslides in modifying channel response to external forcing (e.g. tectonic uplift); landslide-delivered sediment may behave as a tool, enhancing channel incision, or as cover, reducing channel incision. However, the influence of landslides on channel response to an individual flood event remains to be elucidated. Here we explore the influence of landslides on channel response to a 200-yr flood in Colorado, USA. From 9 - 15th September 2013 up to 450 mm of rain fell across a 100 km-wide swath of the Colorado Front Range, triggering >1000 landslides and inducing major flooding in several catchments. The flood caused extensive channel erosion, deposition and planform change, resulting in significant damage to property and infrastructure and even loss of life. We use a combination of pre and post flood LiDAR and field mapping to quantify geomorphic change in several catchments spanning the flooded region. We make a reach-by-reach analysis of channel geomorphic change metrics (e.g. volume of erosion) in relation to landslide sediment input and total stream power as calculated from radar-based rainfall measurements. Preliminary results suggest that landslide-sediment input may complicate the predictive relationship between channel erosion and stream power. Low volumes of landslide sediment input appear to enhance channel erosion (a tools effect), whilst very large volumes appear to reduce channel erosion (a cover effect). These results have implications for predicting channel response to floods and for flood planning and mitigation.

The Barrancas anticline in west-central Argentina: new geomorphic and geologic constraints on the geometry and activity of a fault-related fold

NASA Astrophysics Data System (ADS)

Rimando, J. M.; Schoenbohm, L. M.

2016-12-01

The Barrancas anticline in Mendoza Province, west-central Argentina is a N-NW-oriented, east-vergent fault-bend fold located in the transition from the mainly east-vergent, thin-skinned Argentine Precordillera to the mainly west-vergent, thick-skinned Sierras Pampeanas — one of the most active thrust zones on Earth. Previous studies of the Barrancas anticline interpreted its structure from 2-D and 3-D seismic data. The anticline is a fault-bend fold with multiple segments with different uplift histories and which linked only after 2.3Ma. This study aims to establish the temporal persistence of segmentation and to describe the role, extent and rates of deformation processes involved in the development of the Barrancas anticline from morphometric analyses, geologic and geomorphic mapping, and accurate dating of relevant geomorphic features. Longitudinal profile analysis of streams on the anticline reveals marked differences in normalized steepness index (ksn) between the western and eastern limbs as well as variation along strike. This distribution of ksn values reveals patterns consistent with asymmetry and segmentation of the Barrancas anticline. Swath profiles parallel to the fold axis resemble fault slip distribution profiles which was a basis for segmentation from previous studies. Drainage basin morphometric indices such as hypsometry, drainage density, and basin elongation were also measured. Hypsometric integral values were particularly higher on the west than on the east, possibly indicating younger folding on the western limb. This study will contribute to a better understanding of the nature, extent, timing, and rate of folding at the transition from thin- to thick-skinned thrust deformation in west-central Argentina. Additionally, this study will contribute to assessment of seismic hazards associated with fault-related folds in Argentina and in similar tectonic settings worldwide.

Coupling Self-Organizing Maps with a Naïve Bayesian classifier: A case study for classifying Vermont streams using geomorphic, habitat and biological assessment data

NASA Astrophysics Data System (ADS)

Fytilis, N.; Rizzo, D. M.

2012-12-01

Environmental managers are increasingly required to forecast the long-term effects and the resilience or vulnerability of biophysical systems to human-generated stresses. Mitigation strategies for hydrological and environmental systems need to be assessed in the presence of uncertainty. An important aspect of such complex systems is the assessment of variable uncertainty on the model response outputs. We develop a new classification tool that couples a Naïve Bayesian Classifier with a modified Kohonen Self-Organizing Map to tackle this challenge. For proof-of-concept, we use rapid geomorphic and reach-scale habitat assessments data from over 2500 Vermont stream reaches (~1371 stream miles) assessed by the Vermont Agency of Natural Resources (VTANR). In addition, the Vermont Department of Environmental Conservation (VTDEC) estimates stream habitat biodiversity indices (macro-invertebrates and fish) and a variety of water quality data. Our approach fully utilizes the existing VTANR and VTDEC data sets to improve classification of stream-reach habitat and biological integrity. The combined SOM-Naïve Bayesian architecture is sufficiently flexible to allow for continual updates and increased accuracy associated with acquiring new data. The Kohonen Self-Organizing Map (SOM) is an unsupervised artificial neural network that autonomously analyzes properties inherent in a given a set of data. It is typically used to cluster data vectors into similar categories when a priori classes do not exist. The ability of the SOM to convert nonlinear, high dimensional data to some user-defined lower dimension and mine large amounts of data types (i.e., discrete or continuous, biological or geomorphic data) makes it ideal for characterizing the sensitivity of river networks in a variety of contexts. The procedure is data-driven, and therefore does not require the development of site-specific, process-based classification stream models, or sets of if-then-else rules associated with expert systems. This has the potential to save time and resources, while enabling a truly adaptive management approach using existing knowledge (expressed as prior probabilities) and new information (expressed as likelihood functions) to update estimates (i.e., in this case, improved stream classifications expressed as posterior probabilities). The distribution parameters of these posterior probabilities are used to quantify uncertainty associated with environmental data. Since classification plays a leading role in the future development of data-enabled science and engineering, such a computational tool is applicable to a variety of engineering applications. The ability of the new classification neural network to characterize streams with high environmental risk is essential for a proactive adaptive watershed management approach.

Lateral ramps in the folded Appalachians and in overthrust belts worldwide; a fundamental element of thrust-belt architecture

USGS Publications Warehouse

Pohn, Howard A.

2000-01-01

Lateral ramps are zones where decollements change stratigraphic level along strike; they differ from frontal ramps, which are zones where decollements change stratigraphic level perpendicular to strike. In the Appalachian Mountains, the surface criteria for recognizing the subsurface presence of lateral ramps include (1) an abrupt change in wavelength or a termination of folds along strike, (2) a conspicuous change in the frequency of mapped faults or disturbed zones (extremely disrupted duplexes) at the surface, (3) long, straight river trends emerging onto the coastal plain or into the Appalachian Plateaus province, (4) major geomorphic discontinuities in the trend of the Blue Ridge province, (5) interruption of Mesozoic basins by cross-strike border faults, and (6) zones of modern and probable ancient seismic activity. Additional features related to lateral ramps include tectonic windows, cross-strike igneous intrusions, areas of giant landslides, and abrupt changes in Paleozoic sedimentation along strike. Proprietary strike-line seismic-reflection profiles cross three of the lateral ramps that were identified by using the surface criteria. The profiles confirm their presence and show their detailed nature in the subsurface. Like frontal ramps, lateral ramps are one of two possible consequences of fold-and-thrust-belt tectonics and are common elements in the Appalachian fold-and-thrust belt. A survey of other thrust belts in the United States and elsewhere strongly suggests that lateral ramps at depth can be identified by their surface effects. Lateral ramps probably are the result of thrust sheet motion caused by continued activation of ancient cratonic fracture systems. Such fractures localized the transform faults along which the continental segments adjusted during episodes of sea-floor spreading.

Applications of low altitude photogrammetry for morphometry, displacements, and landform modeling

NASA Astrophysics Data System (ADS)

Gomez, F. G.; Polun, S. G.; Hickcox, K.; Miles, C.; Delisle, C.; Beem, J. R.

2016-12-01

Low-altitude aerial surveying is emerging as a tool that greatly improves the ease and efficiency of measuring landforms for quantitative geomorphic analyses. High-resolution, close-range photogrammetry produces dense, 3-dimensional point clouds that facilitate the construction of digital surface models, as well as a potential means of classifying ground targets using spatial structure. This study presents results from recent applications of UAS-based photogrammetry, including high resolution surface morphometry of a lava flow, repeat-pass applications to mass movements, and fault scarp degradation modeling. Depending upon the desired photographic resolution and the platform/payload flown, aerial photos are typically acquired at altitudes of 40 - 100 meters above the ground surface. In all cases, high-precision ground control points are key for accurate (and repeatable) orientation - relying on low-precision GPS coordinates (whether on the ground or geotags in the aerial photos) typically results in substantial rotations (tilt) of the reference frame. Using common ground control points between repeat surveys results in matching point clouds with RMS residuals better than 10 cm. In arid regions, the point cloud is used to assess lava flow surface roughness using multi-scale measurements of point cloud dimensionality. For the landslide study, the point cloud provides a basis for assessing possible displacements. In addition, the high resolution orthophotos facilitate mapping of fractures and their growth. For neotectonic applications, we compare fault scarp modeling results from UAV-derived point clouds versus field-based surveys (kinematic GPS and electronic distance measurements). In summary, there is a wide ranging toolbox of low-altitude aerial platforms becoming available for field geoscientists. In many instances, these tools will present convenience and reduced cost compared with the effort and expense to contract acquisitions of aerial imagery.

Variable near-surface deformation along the Commerce segment of the Commerce geophysical lineament, southeast Missouri to southern Illinois, USA

USGS Publications Warehouse

Odum, J.K.; Stephenson, W.J.; Williams, R.A.

2003-01-01

Recent studies have demonstrated a plausible link between surface and near-surface tectonic features and the vertical projection of the Commerce geophysical lineament (CGL). The CGL is a 5- to 10-km-wide zone of basement magnetic and gravity anomalies traceable for more than 600 km, extending from Arkansas through southeast Missouri and southern Illinois and into Indiana. Twelve kilometers of high-resolution seismic reflection data, collected at four sites along a 175-km segment of the CGL projection, are interpreted to show varying amounts of deformation involving Tertiary and some Quaternary sediments. Some of the locally anomalous geomorphic features in the northern Mississippi embayment region (i.e., paleoliquefaction features, anomalous directional changes in stream channels, and areas of linear bluff escarpments) overlying the CGL can be correlated with specific faults and/or narrow zones of deformed (faulted and folded) strata that are imaged on high-resolution seismic reflection data. There is an observable change in near-surface deformation style and complexity progressing from the southwest to the northeast along the trace of the CGL. The seismic reflection data collaborate mapping evidence which suggests that this region has undergone a complex history of deformation, some of which is documented to be as young as Quaternary, during multiple episodes of reactivation under varying stress fields. This work, along with that of other studies presented in this volume, points to the existence of at least one major crustal feature outside the currently defined zone of seismic activity (New Madrid Seismic Zone) that should be considered as a significant potential source zone for seismogenic activity within the midcontinent region of the United States. ?? 2003 Elsevier B.V. All rights reserved.

Effects of Jackson Lake dam and Tributaries on the Hydrology and Geomorphology of the Snake River, Grand Teton National Park, Wyoming

NASA Astrophysics Data System (ADS)

Nelson, N. C.; Schmidt, J. C.

2006-05-01

Geomorphic and hydrologic analyses of the Snake River in Grand Teton National Park (GTNP) indicate that flow contributions of tributaries mitigate impacts of regulation. Since a flow regime change in 1958, regulation resulted in a 43 and 35% decrease in estimated unregulated flows immediately downstream of Jackson Lake Dam (JLD) and at Moose (43 km and 5 tributaries downstream of JLD), respectively. Geomorphic evidence indicates that some channel characteristics are more sensitive than others to this decreasing influence of flow regulation. First, entrainment of tracer rocks suggests that the ability of the Snake River to mobilize its bed increases downstream. A greater proportion of the bed became active, and the mobilized clasts moved further, in the two study reaches furthest downstream. Second, repeat mapping from aerial photographs suggest that some changes in channel form are the result of flow regulation and some are the result of climatically driven changes in runoff determined by tributaries. Initial decreases in flows due to regulation may have caused the observed channel narrowing between 1945 and 1969, and greater precipitation causing greater natural flows may have resulted in the subsequent channel widening between 1969 and 1990. Third, flow models were used to obtain the magnitudes of flows necessary to inundate two floodplain surfaces in 4 reaches from JLD to Moose. Recurrence intervals and inundation periods were similar for a narrow, inset floodplain in all 4 reaches, suggesting that this surface developed due to regulation. Recurrence intervals for a much broader and higher floodplain decreased downstream from 9 to 3.2 years and inundation periods increased downstream from 1.1 to 3 days immediately below JLD and at Moose, respectively. This suggests the upper floodplain was formed prior to regulation of the Snake River. Thus, the effects of flow regulation on bed mobility and connectivity between the channel and the upper floodplain decrease downstream as tributaries supply additional streamflow. However, the development of the inset floodplain associated with regulated flows has occurred throughout the study area. These studies indicate that tributaries may reduce most but not necessarily all of the impacts of flow regulation on the geomorphology of the Snake River in GTNP.

Geomorphic Responses to Stream Channel Restoration at Minebank Run, Baltimore County, Maryland, 2002--2008

EPA Science Inventory

Data collected from 2002 through 2008 were used to assess geomorphic characteristics and geomorphic changes over time in a selected reach of Minebank Run, a small urban watershed near Towson, Maryland, prior to and after its physical restoration in 2004 and 2005. Data collected ...

The Promise for Geomorphic Discovery in the South.

ERIC Educational Resources Information Center

Mossa, Joann

1998-01-01

Presents an overview of current geomorphic research in the southern United States. Conveys that the limited historical effort offers both challenges and opportunities for conducting geomorphic work in the region; much is unknown about these unique landscapes. States applied and theoretical geomorphology will benefit the society and future of the…

A conceptual connectivity framework for understanding geomorphic change in human-impacted fluvial systems

NASA Astrophysics Data System (ADS)

Pöppl, Ronald; Keesstra, Saskia; Maroulis, Jerry

2017-04-01

Human-induced landscape change is difficult to predict due to the complexity inherent in both geomorphic and social systems as well as due to emerging coupling relationships between them. To better understand system complexity and system response to change, connectivity has become an important research paradigm within various disciplines including geomorphology, hydrology and ecology. With the proposed conceptual connectivity framework on geomorphic change in human-impacted fluvial systems a cautionary note is flagged regarding the need (i) to include and to systematically conceptualise the role of different types of human agency in altering connectivity relationships in geomorphic systems and (ii) to integrate notions of human-environment interactions to connectivity concepts in geomorphology to better explain causes and trajectories of landscape change. Underpinned by case study examples, the presented conceptual framework is able to explain how geomorphic response of fluvial systems to human disturbance is determined by system-specific boundary conditions (incl. system history, related legacy effects and lag times), vegetation dynamics and human-induced functional relationships (i.e. feedback mechanisms) between the different spatial dimensions of connectivity. It is further demonstrated how changes in social systems can trigger a process-response feedback loop between social and geomorphic systems that further governs the trajectory of landscape change in coupled human-geomorphic systems.

Megafans and Trumpeter Bird Biodiversity-Psophia Phylogeography and Landscape Evolution in Amazonia

NASA Technical Reports Server (NTRS)

Wilkinson, Justin

2014-01-01

Based on geomorphic character and mapped geology, geologists have interpreted the landscape surrounding the Andes Mountains as becoming progressively younger to the East. These sedimentary materials filled the late Miocene swampland that formerly occupied central and western Amazonia. Apart from the ancient landscapes of the Guiana Highlands (top right, figure 1a), Zone Ac is the oldest, followed by Zone Aw, within which megafan Jw is older than megafan Je (figure 1a). DNA-based paleogeography of the trumpeters shows that younger clades diverge from parent lineages with increasing distance from the Andes chain. Thus, Psophia napensis diverges from the P. crepitans parent, and P. ochroptera diverges from P. napensis. The P. ochroptera population is confined solely to the Je megafan (figure 1a). The same trend is seen on the south side of the Amazon depression. Since the timing of the events seems to be of exactly the same order [post-Miocene for the land surfaces and trumpeter divergence within the last 3 million years (figure 1d)], it seems reasonable to think that the megafans provided the substrate on which new bird lineages could speciate. Such physical controls of evolution are becoming more important in the understanding of biodiversity.

Assessment of Shallow-Water Habitat Availability in Modified Dike Structures, Lower Missouri River, 2004

USGS Publications Warehouse

Jacobson, Robert B.; Elliott, Caroline M.; Johnson, Harold E.

2004-01-01

This study documented the effects of wing-dike notching on the availabilit of shallow water habitat in the Lower Missouri River. Five wing dikes were surveyed in late May 2004 after they were notched in early May as part of shallow-water habitat (SWH) rehabilitation activities undertaken by the U.S. Army Corps of Engineers. Surveys included high-resolution hydroacoustic depth, velocity, and substrate mapping. Relations of bottom elevations within the wing dike fields to index discharges and water-surface elevations indicate that little habitat meeting the SWH definition was created immediately following notching. This result is not unexpected, as significant geomorphic adjustment may require large flow events. Depth, velocity, and substrate measurements in the post-rehabilitation time period provide baseline data for monitoring ongoing changes. Differences in elevation and substrate were noted at all sites. Most dike fields showed substantial aggradation and replacement of mud substrate with sandier sediment, although the changes did not result in increased availability of SWH at the index discharge. It is not known how much of the elevation and substrate changes can be attributed directly to notching and how much would result from normal sediment transport variation.

Impact-induced seismic activity on asteroid 433 Eros: a surface modification process.

PubMed

Richardson, James E; Melosh, H Jay; Greenberg, Richard

2004-11-26

High-resolution images of the surface of asteroid 433 Eros revealed evidence of downslope movement of a loose regolith layer, as well as the degradation and erasure of small impact craters (less than approximately 100 meters in diameter). One hypothesis to explain these observations is seismic reverberation after impact events. We used a combination of seismic and geomorphic modeling to analyze the response of regolith-covered topography, particularly craters, to impact-induced seismic shaking. Applying these results to a stochastic cratering model for the surface of Eros produced good agreement with the observed size-frequency distribution of craters, including the paucity of small craters.

Geomorphic and Structural Evidence for Rolling Hinge Style Deformation in the Footwall of an Active Low Angle Normal Fault, Mai'iu Fault, Woodlark Rift, SE Papua New Guinea

NASA Astrophysics Data System (ADS)

Mizera, M.; Little, T.; Norton, K. P.; Webber, S.; Ellis, S. M.; Oesterle, J.

2016-12-01

While shown to operate in oceanic crust, rolling hinge style deformation remains a debated process in metamorpic core complexes (MCCs) in the continents. The model predicts that unloading and isostatic uplift during slip causes a progressive back-tilting in the upper crust of a normal fault that is more steeply dipping at depth. The Mai'iu Fault in the Woodlark Rift, SE Papua New Guinea, is one of the best-exposed and fastest slipping (probably >7 mm/yr) active low-angle normal faults (LANFs) on Earth. We analysed structural field data from this fault's exhumed slip surface and footwall, together with geomorphic data interpreted from aerial photographs and GeoSAR-derived digital elevation models (gridded at 5-30 m spacing), to evaluate deformational processes affecting the rapidly exhuming, domal-shaped detachment fault. The exhumed fault surface emerges from the ground at the rangefront near sea level with a northward dip of 21°. Up-dip, it is well-preserved, smooth and corrugated, with some fault remnants extending at least 29 km in the slip direction. The surface flattens over the crest of the dome, beyond where it dips S at up to 15°. Windgaps perched on the crestal main divide of the dome, indicate both up-dip tectonic advection and progressive back-tilting of the exhuming fault surface. We infer that slip on a serial array of m-to-km scale up-to-the-north, steeply S-dipping ( 75°) antithetic-sense normal faults accommodated some of the exhumation-related, inelastic bending of the footwall. These geomorphically well expressed faults strike parallel to the main Mai'iu fault at 110.9±5°, have a mean cross-strike spacing of 1520 m, and slip with a consistent up-to-the-north sense of throw ranging from <5 m to 120 m. Apparently the Mai'iu Fault was able to continue slipping despite having to negotiate this added fault-roughness. We interpret the antithetic faulting to result from bending stresses, and to provide the first clear examples of rolling hinge-style accommodation structures on a continental MCC.

Proximity of the Seismogenic Dog Valley Fault to Stampede and Prosser Creek Dams Near Truckee, California

NASA Astrophysics Data System (ADS)

Cronin, V. S.; Strasser, M. P.

2017-12-01

The M 6.0 Truckee earthquake of 12 September 1966 caused a variety of surface effects observed over a large area, but the rupture plane of the causative fault did not displace the ground surface. The fault that generated the earthquake was named the Dog Valley fault [DVF], and its ground trace was assumed to be within a zone of subparallel drainage lineaments. The plunge and trend of the dip vector for the best fault-plane solution is 80° 134° with 0° rake, corresponding to a steep NE striking left-lateral strike-slip fault (Tsai and Aki, 1970). The Stampede Dam was completed along the trend of the Dog Valley fault in 1970, just four years after the Truckee earthquake, and impounds almost a quarter-million acre-feet of water. Failure of Stampede Dam would compromise Boca Dam downstream and pose a catastrophic threat to people along the Truckee River floodplain to Reno and beyond. Two 30 m long trenches excavated across a suspected DVF trend by the US Bureau of Reclamation in the 1980s did not find evidence of faulting (Hawkins et al., 1986). The surface trace of the DVF has remained unknown. We used the Seismo-Lineament Analysis Method [SLAM] augmented with a total least squares analysis of the focal locations of known or suspected aftershocks, along with focal mechanism data from well located events since 1966, to constrain the search for the DVF ground trace. Geomorphic analysis of recently collected aerial lidar data along this composite seismo-lineament has lead to a preliminary interpretation that the DVF might extend from the Prosser Creek Reservoir near 39.396°N 120.168°W through or immediately adjacent to the Stampede Dam structure. A second compound geomorphic lineament is sub-parallel to this line 1.6 km to the northwest, and might represent another strand of the DVF. As noted by Hawkins et al. (1986), human modification of the land surface complicates structural-geomorphic analysis. Fieldwork in 2016 took advantage of drought conditions to examine the exposed shoreface of Stampede Reservoir near the dam, and exposures of steeply dipping strike-slip faults were found.

Holocene soil-geomorphic surfaces influence the role of salmon-derived nutrients in the coastal temperate rainforest of Southeast Alaska

Treesearch

David V. D' Amore; Nicholas S. Bonzey; Jacob Berkowitz; Janine Rüegg; Scott Bridgham

2011-01-01

The influence of salmon-derived nutrients (SDN) is widely accepted as a potential factor in the maintenance of aquatic and terrestrial productivity in North American Coastal rainforests. Holocene alluvial landforms are intimately connected with the return of anadromous salmon, but the influence of the soils that occupy these landforms and support this important...

Hydraulic characteristics and dynamics of beaver dams in a Midwestern U.S. agricultural waershed

Treesearch

M.C. McCullough; D.E. Eisenhauer; M.G. Dosskey; D.M. Admiraal

2006-01-01

Populations of Noth America beaver (castor canadensis) have increased in the past decades throughout the Midwestern U.S., leading to an increase in the frequency of beaver dams in small streams. Beaver dams form ponds and slow water velocity. Multiple dams create a stair-step effect on the water surface profile. The hydraulic and geomorphic influence of beaver dams on...

Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

USGS Publications Warehouse

Farrell, K.M.

2001-01-01

This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution proposed by Smith et al. (Sedimentology, vol. 36 (1989) 1) is revised to include facies and geometries consistent with a bayfill model. By analogy with delta lobes, the avulsion sequence is a parasequence, provided that its definition is modified to be independent from sea level. In non-marine settings, facies contacts at the tops of regional peats, coals, and paleosols are analogous to marine flooding surfaces. A parasequence is redefined here as a relatively conformable succession of genetically related strata or landforms that is bounded by regional flooding surfaces or their correlative surfaces. This broader definition incorporates the concept of landscape evolution between regional flooding surfaces in a variety of depositional settings. With respect to landscape evolution, accommodation space has three spatial dimensions - vertical (x), lateral (y), and down-the-basin (z). A flood basin fills in as landforms vertically (x) and laterally accrete (y), and prograde down-the-basin (z). Vertical aggradation is limited by the elevation of maximum flood stage (local base level). Differential tectonism and geomorphology control the slope of the flood basin floor and the direction of landscape evolution. These processes produce parasequences that include inclined stratal surfaces and oriented, stacked macroforms (clinoforms) that show the magnitude and direction of landscape evolution. ?? 2001 Elsevier Science B.V. All rights reserved.

Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

NASA Astrophysics Data System (ADS)

Farrell, K. M.

2001-02-01

This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution proposed by Smith et al. (Sedimentology, vol. 36 (1989) 1) is revised to include facies and geometries consistent with a bayfill model. By analogy with delta lobes, the avulsion sequence is a parasequence, provided that its definition is modified to be independent from sea level. In non-marine settings, facies contacts at the tops of regional peats, coals, and paleosols are analogous to marine flooding surfaces. A parasequence is redefined here as a relatively conformable succession of genetically related strata or landforms that is bounded by regional flooding surfaces or their correlative surfaces. This broader definition incorporates the concept of landscape evolution between regional flooding surfaces in a variety of depositional settings. With respect to landscape evolution, accommodation space has three spatial dimensions — vertical ( x), lateral ( y), and down-the-basin ( z). A flood basin fills in as landforms vertically ( x) and laterally accrete ( y), and prograde down-the-basin ( z). Vertical aggradation is limited by the elevation of maximum flood stage (local base level). Differential tectonism and geomorphology control the slope of the flood basin floor and the direction of landscape evolution. These processes produce parasequences that include inclined stratal surfaces and oriented, stacked macroforms (clinoforms) that show the magnitude and direction of landscape evolution.

Geomorphic consequences of rapid deglaciation at Pasterze Glacier, Hohe Tauern Range, Austria, between 2010 and 2013 based on repeated terrestrial laser scanning data

NASA Astrophysics Data System (ADS)

Avian, M.; Kellerer-Pirklbauer, A.; Lieb, G. K.

2018-06-01

Since the end of the Little Ice Age around 1850 CE glaciers in the Alps have been receding dramatically. This study aimed to quantify and characterize the geomorphic and landform changes of a 0.9 km2 large proglacial area at the largest glacier in Austria (Pasterze Glacier, Austria, N 47°04‧, E 12°44‧). Point clouds from multiple terrestrial laserscanning (TLS) and different image data were used to quantify surface elevation changes and distinguish different types of erosional and depositional landforms during the period 2010-2013. Results indicate that the study area is characterized by a total volume loss of 1,309,000 m3. Excluding the area which was deglaciated, the volume loss equals 275,000 m3 in the period 2010-13. The decrease is related to sediment transfer out of study area and due to sediment-buried glacier ice which is slowly melting. The landform classification reveals that drift mantled slopes are most frequent (20.9% of the study area in 2013) next to ice contact terrace landforms (19.7%). In terms of vertical surface elevation changes, our results suggest distinguishing between 3 distinct domains within the study area: (i) a flat valley bottom area consisting of water/sandur areas and ice-cored landforms dominated by widespread subsurface ice melting and lateral fluvial (and thermal) erosion; (ii) a gently-sloping footslope area consisting of ice-contact sediments, former ice marginal channels and deep incised gullies with corresponding debris cones dominated by linear erosion and corresponding deposition; and (iii) a steep lateral slope area mainly built up of consolidated drift material with incised gullies dominated by linear erosion. Our results not only confirm the previously revealed high geomorphic activity for proglacial areas of alpine glaciers in terms of surface elevation variations, they also highlight that landforms might change substantially from one year to the next not only because of erosional/depositional processes, but also because of the melting of buried dead-ice bodies.

Geomorphic analysis of large alluvial rivers

NASA Astrophysics Data System (ADS)

Thorne, Colin R.

2002-05-01

Geomorphic analysis of a large river presents particular challenges and requires a systematic and organised approach because of the spatial scale and system complexity involved. This paper presents a framework and blueprint for geomorphic studies of large rivers developed in the course of basic, strategic and project-related investigations of a number of large rivers. The framework demonstrates the need to begin geomorphic studies early in the pre-feasibility stage of a river project and carry them through to implementation and post-project appraisal. The blueprint breaks down the multi-layered and multi-scaled complexity of a comprehensive geomorphic study into a number of well-defined and semi-independent topics, each of which can be performed separately to produce a clearly defined, deliverable product. Geomorphology increasingly plays a central role in multi-disciplinary river research and the importance of effective quality assurance makes it essential that audit trails and quality checks are hard-wired into study design. The structured approach presented here provides output products and production trails that can be rigorously audited, ensuring that the results of a geomorphic study can stand up to the closest scrutiny.

Identification of areas of recharge and discharge using Landsat-TM satellite imagery and aerial photography mapping techniques

NASA Astrophysics Data System (ADS)

Salama, R. B.; Tapley, I.; Ishii, T.; Hawkes, G.

1994-10-01

Aerial photographs (AP) and Landsat (TM) colour composites were used to map the geomorphology, geology and structures of the Salt River System of Western Australia. Geomorphic features identified are sand plains, dissected etchplain, colluvium, lateritic duricrust and rock outcrops. The hydrogeomorphic units include streams, lakes and playas, palaeochannels and palaeodeltas. The structural features are linear and curvilinear lineaments, ring structures and dolerite dykes. Suture lines control the course of the main river channel. Permeable areas around the circular granitic plutons were found to be the main areas of recharge in the uplands. Recharge was also found to occur in the highly permeable areas of the sandplains. Discharge was shown to be primarily along the main drainage lines, on the edge of the circular sandplains, in depressions and in lakes. The groundwater occurrence and hydrogeological classification of the recharge potential of the different units were used to classify the mapped areas into recharge and discharge zones. The results also show that TM colour composites provide a viable source of data comparable with AP for mapping and delineating areas of recharge and discharge on a regional scale.

Documenting human transformation and establishing the reference condition of large river systems using Corona images: a case study from the Ganga River basin, India

NASA Astrophysics Data System (ADS)

Sinha, Rajiv; Pipil, Shobhit; Carbonneau, Patrice; Galiatsatos, Nikolaos

2016-04-01

The Ganga basin in northern India is one of the most populous river basin in the world with nearly half a billion inhabitants. In the post-independence era, population expansion and human interventions have left the ecosystem of the Ganga in a severely damaged state with dwindling water levels, pollution due to human activity and natural sediment transport severely perturbed by dams and barrages. Fortunately, there is a growing recognition by the policy managers in India that the restoration of the Ganga to a healthier status, closer to its original unperturbed state, would set a strong foundation to future, greener, economic growth in Northern India. However, given the past six decades of fast development, efforts to restore the Ganga to its original condition are faced with a fundamental question: What was the original state of the Ganga? Answering this question will require some knowledge of the former course of the Ganga and of the farming and urban density of the surrounding plains before the impacts of human disturbance could be felt. We have made use of the Corona spy satellite program that collected a large number of earth observation photos in the 1960s. These photos, now declassified, offer us a unique view of the Ganga at the very early stages of intense development and thus before the worst ecological damages occurred. However, actual usage of these images poses significant technical challenges. In the design of the Corona cameras, very high resolution comes at the cost of complex distortions. Furthermore, we have no information on the exact position and orientation of the satellite at the time of image acquisition so an accurate reprojection of the image into conventional map coordinates is not straightforward. We have developed a georectification process based on polynomial transformation to achieve a positional accuracy of ±20m for the area of our interest. Further, We have developed an object-based classification method that uses both texture and raw DN values in order to establish the LULC of the Ganga plain in the 1960s. Finally, geomorphic mapping within the Ganga valley margin in selected reaches was performed using on-screen feature identification with some validation from Bing maps and Google images. A comparison of our LULC and geomorphic maps generated from Corona images with those from modern data shows large changes in the position and form of the river as well as the land cover in the Ganga valley during the last five decades primarily in response to anthropogenic forcings. In certain areas, the urban centres have grown 4-5 fold and channel morphology has changed remarkably in response to the construction of barrages and other interventions. Several reaches of excessive sediment aggradation and significant channel area reduction are identified. The identification of such 'hotspots' of geomorphic changes and their causal factors can help the river managers prioritizing the river rehabilitation efforts in selected reaches and establishing the 'reference' conditions to target in near future.

A mountain river sediment cascade and its controls: the Schöttlbach torrent, Styria

NASA Astrophysics Data System (ADS)

Lutzmann, Silke; Stangl, Johannes; Sass, Oliver

2017-04-01

Steep alpine headwater torrents are characterized by episodic heavy floods and bedload pulses triggered by local high-intensity mountain rainstorms. They frequently pose serious risks and damage in the densely populated East Alpine Region. It is important to understand where critical sediments are mobilized, how much bedload is delivered to the outlet and what controls the variability. We present a concept to quantify the sediment cascade's components and influencing factors for the Schöttlbach torrent - a 71 km2 non-glaciated catchment in the Niedere Tauern mountain Range in Styria, Austria. Geomorphic mapping is used to identify primary bedload sources on slope as well as patterns of lithology, slope-channel coupling and vegetation conditioning erosion intensity. We apply modern near-range measuring techniques (TLS, Structure from Motion) to monitor erosion rates from representative erosion sites and sediment delivery rates at the outlet since 2014. These measurements are interpreted based on the geomorphic map to derive a catchment-wide seasonal sediment budget. To explain seasonal variations we evaluate precipitation and discharge data from a dense station network as storm precipitation and runoff events are the main triggers of torrent sediment mobilization. Torrent reaches in instable glaciofluvial sediments of the last glaciation show high average erosion rates of ca. 0.08 m/a from 2014 to 2016 surpassing rates in deeply weathered bedrock reaches by an order of magnitude (approx. 0.006 m/a). We model a torrent-wide erosion volume of 2000 m3/a opposing an output of 7000 m3/a in that period. We attribute parts of this discrepancy to a sediment wave reworking signal of an extreme flood event in 2011.

Stream network analysis and geomorphic flood plain mapping from orbital and suborbital remote sensing imagery application to flood hazard studies in central Texas

NASA Technical Reports Server (NTRS)

Baker, V. R. (Principal Investigator); Holz, R. K.; Hulke, S. D.; Patton, P. C.; Penteado, M. M.

1975-01-01

The author has identified the following significant results. Development of a quantitative hydrogeomorphic approach to flood hazard evaluation was hindered by (1) problems of resolution and definition of the morphometric parameters which have hydrologic significance, and (2) mechanical difficulties in creating the necessary volume of data for meaningful analysis. Measures of network resolution such as drainage density and basin Shreve magnitude indicated that large scale topographic maps offered greater resolution than small scale suborbital imagery and orbital imagery. The disparity in network resolution capabilities between orbital and suborbital imagery formats depends on factors such as rock type, vegetation, and land use. The problem of morphometric data analysis was approached by developing a computer-assisted method for network analysis. The system allows rapid identification of network properties which can then be related to measures of flood response.

Rapid fluvial incision of a late Holocene lava flow: Insights from LiDAR, alluvial stratigraphy, and numerical modeling

USGS Publications Warehouse

Sweeney, Kristin; Roering, Joshua J.

2016-01-01

Volcanic eruptions fundamentally alter landscapes, paving over channels, decimating biota, and emplacing fresh, unweathered material. The fluvial incision of blocky lava flows is a geomorphic puzzle. First, high surface permeability and lack of sediment should preclude geomorphically effective surface runoff and dissection. Furthermore, past work has demonstrated the importance of extreme floods in driving incision via column toppling and plucking in columnar basalt, but it is unclear how incision occurs in systems where surface blocks are readily mobile. We examine rapid fluvial incision of the Collier lava flow, an andesitic Holocene lava flow in the High Cascades of Oregon. Since lava flow emplacement ∼1600 yr ago, White Branch Creek has incised bedrock gorges up to 8 m deep into the coherent core of the lava flow and deposited >0.2 km3 of sediment on the lava flow surface. Field observation points to a bimodal discharge regime in the channel, with evidence for both annual snowmelt runoff and outburst floods from Collier glacier, as well as historical evidence of vigorous glacial meltwater. To determine the range of discharge events capable of incision in White Branch Creek, we used a mechanistic model of fluvial abrasion. We show that the observed incision implies that moderate flows are capable of both initiating channel formation and sustaining incision. Our results have implications for the evolution of volcanic systems worldwide, where glaciation and/or mass wasting may accelerate fluvial processes by providing large amounts of sediment to otherwise porous, sediment-starved landscapes.

Integrating Geomorphic and Social Dynamics in the Analysis of Anthropogenic Landforms: Examining Landscape Evolution of Terrain Modified by Agricultural Terracing

NASA Astrophysics Data System (ADS)

Glaubius, J.; Maerker, M.

2016-12-01

Anthropogenic landforms, such as mines and agricultural terraces, are impacted by both geomorphic and social processes at varying intensities through time. In the case of agricultural terraces, decisions regarding terrace maintenance are intertwined with land use, such as when terraced fields are abandoned. Furthermore, terrace maintenance and land use decisions, either jointly or separately, may be in response to geomorphic processes, as well as geomorphic feedbacks. Previous studies of these complex geomorphic systems considered agricultural terraces as static features or analyzed only the geomorphic response to landowner decisions. Such research is appropriate for short-term or binary landscape scenarios (e.g. the impact of maintained vs. abandoned terraces), but the complexities inherent in these socio-natural systems requires an approach that includes both social and geomorphic processes. This project analyzes feedbacks and emergent properties in terraced systems by implementing a coupled landscape evolution model (LEM) and agent-based model (ABM) using the Landlab and Mesa modeling libraries. In the ABM portion of the model, agricultural terraces are conceptualized using a life-cycle stages schema and implemented using Markov Decision Processes to simulate the changing geomorphic impact of terracing based on human decisions. This paper examines the applicability of this approach by comparing results from a LEM-only model against the coupled LEM-ABM model for a terraced region. Model results are compared by quantify and spatial patterning of sediment transport. This approach fully captures long-term landscape evolution of terraced terrain that is otherwise lost when the life-cycle of terraces is not considered. The coupled LEM-ABM approach balances both environmental and social processes so that the socio-natural feedbacks in such anthropogenic systems can be disentangled.

Hydrated mineral stratigraphy of Ius Chasma, Valles Marineris

USGS Publications Warehouse

Roach, L.H.; Mustard, J.F.; Swayze, G.; Milliken, R.E.; Bishop, J.L.; Murchie, S.L.; Lichtenberg, K.

2010-01-01

New high-resolution spectral and morphologic imaging of deposits on walls and floor of Ius Chasma extend previous geomorphic mapping, and permit a new interpretation of aqueous processes that occurred during the development of Valles Marineris. We identify hydrated mineralogy based on visible-near infrared (VNIR) absorptions. We map the extents of these units with CRISM spectral data as well as morphologies in CTX and HiRISE imagery. Three cross-sections across Ius Chasma illustrate the interpreted mineral stratigraphy. Multiple episodes formed and transported hydrated minerals within Ius Chasma. Polyhydrated sulfate and kieserite are found within a closed basin at the lowest elevations in the chasma. They may have been precipitates in a closed basin or diagenetically altered after deposition. Fluvial or aeolian processes then deposited layered Fe/Mg smectite and hydrated silicate on the chasma floor, postdating the sulfates. The smectite apparently was weathered out of Noachian-age wallrock and transported to the depositional sites. The overlying hydrated silicate is interpreted to be an acid-leached phyllosilicate transformed from the underlying smectite unit, or a smectite/jarosite mixture. The finely layered smectite and massive hydrated silicate units have an erosional unconformity between them, that marks a change in surface water chemistry. Landslides transported large blocks of wallrock, some altered to contain Fe/Mg smectite, to the chasma floor. After the last episode of normal faulting and subsequent landslides, opal was transported short distances into the chasma from a few m-thick light-toned layer near the top of the wallrock, by sapping channels in Louros Valles. Alternatively, the material was transported into the chasma and then altered to opal. The superposition of different types of hydrated minerals and the different fluvial morphologies of the units containing them indicate sequential, distinct aqueous environments, characterized by alkaline, then circum-neutral, and finally very acidic surface or groundwater chemistry. ?? 2009 Elsevier Inc. All rights reserved.

Geomorphic Change Detection and Quantification Using LiDAR, SONAR and RTK-GPS of Sandbars along the Snake River in Hells Canyon

NASA Astrophysics Data System (ADS)

Morehead, M. D.; Wilson, T.; Butler, M.; Seal, N.

2012-12-01

Sediment depletion downstream of large dams causes long-term geomorphic change along a river reach. Short- and long-term, natural and human-altered discharge patterns cause additional geomorphic change. Annual high-resolution, topobathymetry data are being collected on sandbars to track patterns of geomorphic and volumetric change through time. The sandbars are located along the Hells Canyon reach of the Snake River on the Oregon/Idaho border. The bars are downstream of a number of dams that have cut off the upstream source of sand to the Hells Canyon reach. We are combining LiDAR data for above water areas, multibeam SONAR data for below water areas and RTK-GPS data for the water/land interface and densely vegetated areas. Idaho Power has installed and surveyed a control point network to allow accurate positioning of the data and aligning of the various data sets. Data densities are a few points per square meter with the RTK-GPS, tens of points per square meter with the SONAR, and up to hundreds of points per square meter with the ground-based LiDAR. Automated and manual methods are being used to clean the point cloud data. A number of techniques are being used to convert the point clouds to grids, typically utilizing a unique technique for each data type (GPS, LiDAR, and SONAR). Surface roughness data are being used to determine the edges of the sand region, especially in the underwater area where we do not have visual confirmation of the boundary. After the different data types are gridded, they are combined to create seamless surfaces which are then analyzed. The morphologies of the central crest and the back channel of the sandbars are changing between years. In years with higher than average spring flows, the central crest of the sandbars increases in elevation and the back channels deepen. In years with moderate and low spring flows, the height of the crests decline and the back channels fill in. The flattening of the sandbars is attributed to natural redistribution processes and anthropogenic use. The cut-banks behind the sandbars have typically not retreated during the study period (8 years). Volumetric differences show that the cut/fill patterns are consistent over large areas of each bar. The annual morphologic changes are consistent among the sampled bars. The time series is just starting to be long enough to assess long-term trends in bar volume and morphology as opposed to inter-annual variability. The increased availability of high-density SONAR and LiDAR data has substantially aided our efforts to detect and quantify geomorphic change along the Snake River. The data editing and analysis techniques for these high-density data sets are advancing rapidly. Improvements in error analysis and within grid cell data proprieties are being developed to document the accuracy of the results and determine other morphological properties.

EAARL Topography-Sagamore Hill National Historic Site

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Travers, Laurinda J.

2007-01-01

This Web site contains lidar-derived bare earth (BE) and first return (FR) topography maps and GIS files for the Sagamore Hill National Historic Site. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL topography: Cape Cod National Seashore

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Travers, Laurinda J.

2007-01-01

This Web site contains 90 Lidar-derived bare earth topography maps and GIS files for the Cape Cod National Seashore. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Florida Integrated Science Center (FISC) St. Petersburg, Florida, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.

EAARL topography: Thomas Stone National Historic Site

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

2007-01-01

This Web site contains Lidar-derived topography (first return and bare earth) maps and GIS files for Thomas Stone National Historic Site in Maryland. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL topography: Gulf Islands National Seashore: Florida

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

2007-01-01

This Web site contains 33 lidar-derived bare earth topography maps and GIS files for the Gulf Islands National Seashore-Florida. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS), Gulf Coast Network, Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL topography: Gulf Islands National Seashore: Mississippi

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

2007-01-01

This Web site contains 30 lidar-derived bare earth topography maps and GIS files for the Gulf Islands National Seashore-Mississippi. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS) Gulf Coast Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL submarine topography: Florida Keys National Marine Sanctuary

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Woolard, Jason; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

2007-01-01

This Web site contains 46 Lidar-derived submarine topography maps and GIS files for the Florida Keys National Marine Sanctuary. These Lidar-derived submarine topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Oceanic and Atmospheric Administration (NOAA), Remote Sensing Division, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography within cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.

EAARL Submarine Topography - Northern Florida Keys Reef Tract

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Travers, Laurinda J.; Wilson, Iris

2007-01-01

This Web site contains 32 Lidar-derived bare earth topography maps and GIS files for the Northern Florida Keys Reef Tract. These lidar-derived submarine topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL topography: Gateway National Recreation Area

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

2007-01-01

This Web site contains Lidar-derived topography (bare earth) maps and GIS files for the Sandy Hook Unit within Gateway National Recreation Area in New Jersey. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL topography: Assateague Island National Seashore

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Travers, Laurinda J.

2007-01-01

This Web site contains 58 lidar-derived bare earth topography maps and GIS files for the Assateague Island National Seashore. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.

EAARL topography: George Washington Birthplace National Monument

USGS Publications Warehouse

Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

2007-01-01

This Web site contains Lidar-derived topography (first return and bare earth) maps and GIS files for George Washington Birthplace National Monument in Virginia. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.

(abstract) Topographic Signatures in Geology

NASA Technical Reports Server (NTRS)

Farr, Tom G.; Evans, Diane L.

1996-01-01

Topographic information is required for many Earth Science investigations. For example, topography is an important element in regional and global geomorphic studies because it reflects the interplay between the climate-driven processes of erosion and the tectonic processes of uplift. A number of techniques have been developed to analyze digital topographic data, including Fourier texture analysis. A Fourier transform of the topography of an area allows the spatial frequency content of the topography to be analyzed. Band-pass filtering of the transform produces images representing the amplitude of different spatial wavelengths. These are then used in a multi-band classification to map units based on their spatial frequency content. The results using a radar image instead of digital topography showed good correspondence to a geologic map, however brightness variations in the image unrelated to topography caused errors. An additional benefit to the use of Fourier band-pass images for the classification is that the textural signatures of the units are quantative measures of the spatial characteristics of the units that may be used to map similar units in similar environments.

Controls on the Seafloor Exposure of Detachment Fault Surfaces

NASA Astrophysics Data System (ADS)

Olive, J. A. L.; Parnell-Turner, R. E.; Escartin, J.; Smith, D. K.; Petersen, S.

2017-12-01

Morphological and seismological evidence suggests that asymmetric accretion involving oceanic detachment faulting takes place along 40% of the Northern Mid-Atlantic Ridge. However, seafloor exposures of corrugated slip surfaces -a telltale sign of this kind of faulting- remain scarce and spatially limited according to multibeam bathymetric surveys. This raises the question of whether geomorphic processes can hinder the exposure of pristine fault surfaces during detachment growth. We address this problem by analyzing ≤2-m resolution bathymetry data from four areas where corrugated surfaces emerge from the seafloor (13º20'N, 16º25'N, 16º36'N, and TAG). We identify two key processes capable of degrading or masking a corrugated large-offset fault surface. The first is gravitational mass wasting of steep (>25º) slopes, which is widespread in the breakaway region of most normal faults. The second is blanketing of the shallow-dipping termination area by a thin apron of hanging wall-derived debris. We model this process using critical taper theory, and infer low effective friction coefficients ( 0.15) on the emerging portion of detachment faults. A corollary to this result is that faults emerging from the seafloor with an angle <10º are more likely to blanket themselves under an apron of hanging wall debris. Optimal exposure of detachment surfaces therefore occurs when the fault emerges at slopes between 10° and 25º. We generalize these findings into a simple model for the progressive exhumation and flexural rotation of detachment footwalls, which accounts for the continued action of seafloor geomorphic processes. Our model suggests that many moderate-offset `blanketed' detachments may exist along slow mid-ocean ridges, but their corrugated surfaces are unlikely to be detected in shipboard multibeam bathymetry (e.g., TAG). Furthermore, many `irregular massifs' may correspond to the degraded footwalls of detachment faults.

Discovery, Controls, and Hazards of Widespread Deep-Seated Gravitational Slope Deformation in the Etsumi Mountains, Central Japan

NASA Astrophysics Data System (ADS)

Kaneda, Heitaro; Kono, Taiyo

2017-12-01

Deep-seated gravitational slope deformation (DSGSD) is a largely unnoticed but important long-term mass wasting process that may result in catastrophic failure of mountain slopes. Manifested by small topographic irregularities such as ridge-parallel scarps and linear depressions, it has been predominantly reported in alpine landscapes above timber lines. On the basis of area-wide high-resolution topographic data acquired by light detection and ranging (lidar) surveys, we here show that 96% of existing gravitational scarps have been hidden under forest canopies in the Etsumi Mountains, central Japan. The scarps are surprisingly widespread over the mountains with a mean line density of as large as 0.87 km/km2. Our analyses of the scarp distribution suggest that uphill-facing scarps are primary geomorphic signals of DSGSD with a destabilized rock mass larger than 105 m2, whereas downhill-facing scarps principally occur in response to more localized slope deformation. In terms of controls, topography is by far the most influential factor in triggering and promoting DSGSD. Despite the M 7.5 earthquake in 1891, impact of large local earthquakes proves to be not very strong. Comparison with preexisting landslide maps further suggests that DSGSD and large-scale landslides are not different slope processes but represent different stages of the same process. Our results highlight limitations of aerial-photograph interpretation in forest-covered mountains and the need for lidar-assisted mapping for deeper understanding of this long-term process and interactions between surface and tectonic processes.

Social-ecological resilience and geomorphic systems

NASA Astrophysics Data System (ADS)

Chaffin, Brian C.; Scown, Murray

2018-03-01

Governance of coupled social-ecological systems (SESs) and the underlying geomorphic processes that structure and alter Earth's surface is a key challenge for global sustainability amid the increasing uncertainty and change that defines the Anthropocene. Social-ecological resilience as a concept of scientific inquiry has contributed to new understandings of the dynamics of change in SESs, increasing our ability to contextualize and implement governance in these systems. Often, however, the importance of geomorphic change and geomorphological knowledge is somewhat missing from processes employed to inform SES governance. In this contribution, we argue that geomorphology and social-ecological resilience research should be integrated to improve governance toward sustainability. We first provide definitions of engineering, ecological, community, and social-ecological resilience and then explore the use of these concepts within and alongside geomorphology in the literature. While ecological studies often consider geomorphology as an important factor influencing the resilience of ecosystems and geomorphological studies often consider the engineering resilience of geomorphic systems of interest, very few studies define and employ a social-ecological resilience framing and explicitly link the concept to geomorphic systems. We present five key concepts-scale, feedbacks, state or regime, thresholds and regime shifts, and humans as part of the system-which we believe can help explicitly link important aspects of social-ecological resilience inquiry and geomorphological inquiry in order to strengthen the impact of both lines of research. Finally, we discuss how these five concepts might be used to integrate social-ecological resilience and geomorphology to better understand change in, and inform governance of, SESs. To compound these dynamics of resilience, complex systems are nested and cross-scale interactions from smaller and larger scales relative to the system of interest can play formative roles during periods of collapse and reorganization. Large- and small-scale disturbances as well as large-scale system memory/capacity and small-scale innovation can have significant impacts on the trajectory of a reorganizing system (Gunderson and Holling, 2002; Chaffin and Gunderson, 2016). Attempts to measure the property of ecological resilience across complex systems amounts to attempts to measure the persistence of system-controlling variables, including processes, parameters, and important feedbacks, when the system is exposed to varying degrees of disturbance (Folke, 2016).

Geomorphic and geologic evidence for slip along the San Bernardino strand of the San Andreas Fault System through the San Gorgonio Pass structural knot, southern California

NASA Astrophysics Data System (ADS)

Kendrick, K. J.; Matti, J. C.

2017-12-01

The San Gorgonio Pass (SGP) region of southern California represents an extraordinarily complex section of the San Andreas Fault (SAF) zone, often referred to as a structural knot. Complexity is expressed both structurally and geomorphically, and arises because multiple strands of the SAF have evolved here in Quaternary time. Our integration of geologic and geomorphic analyses led to recognition of multiple fault-bounded blocks characterized by crystalline rocks that have similar physical properties. Hence, any morphometric differences in hypsometric analysis, slope, slope distribution, texture, and stream-power measurements and discontinuities reflect landscape response to tectonic processes rather than differences in lithology. We propose that the differing morphometry of the two blocks on either side of the San Bernardino strand (SBS) of the SAF, the high-standing Kitching Peak block to the east and the lower, more subdued Pisgah Peak block to the west, strongly suggests that the blocks experienced different uplift histories. This difference in uplift histories, in turn suggests that dextral slip occurred over a long time interval on the SBS—despite long-lived controversy raised by the fact that, at the surface, a throughgoing trace of the SBS is not present at this location. A different tectonic history between the two blocks is consistent with the gravity data which indicate that low-density rocks underthrusting the Kitching Peak block are absent below the Pisgah Peak block (Langenheim et al., 2015). Throughgoing slip on the SBS implied by geomorphic differences between the two blocks is also consistent with displaced geologic and geomorphic features. We find compelling evidence for discrete offsets of between 0.6 and 6 km of dextral slip on the SBS, including offset of fluvial and landslide deposits, and beheaded drainages. Although we lack numerical age control for the offset features, the degree of soil development associated with displaced landforms suggests that the SBS has had a longer geologic history than previously proposed, and that this fault strand may have experienced episodic activity. Landscape evolution and geologic evidence together require that dextral slip on the SAF must have continued through the SGP structural knot during an extended interval in the past.

Scaling Laws in Arctic Permafrost River Basins: Statistical Signature in Transition

NASA Astrophysics Data System (ADS)

Rowland, J. C.; Gangodagamage, C.; Wilson, C. J.; Prancevic, J. P.; Brumby, S. P.; Marsh, P.; Crosby, B. T.

2011-12-01

The Arctic landscape has been shown to be fundamentally different from the temperate landscape in many ways. Long winters and cold temperatures have led to the development of permafrost, perennially frozen ground, that controls geomorphic processes and the structure of the Arctic landscape. Climate warming is causing changes in permafrost and the active layer (the seasonally thawed surface layer) that is driving an increase in thermal erosion including thermokarst (collapsed soil), retrogressive thaw slumps, and gullies. These geomorphic anomalies in the arctic landscapes have not been well quantified, even though some of the landscape geomorphic and hydrologic characteristics and changes are detectable by our existing sensor networks. We currently lack understanding of the fundamental fluvio-thermal-erosional processes that underpin Arctic landscape structure and form, which limits our ability to develop models to predict the landscape response to current and future climate change. In this work, we seek a unified framework that can explain why permafrost landscapes are different from temperate landscapes. We use high resolution LIDAR data to analyze arctic geomorphic processes at a scale of less than a 1 m and demonstrate our ability to quantify the fundamental difference in the arctic landscape. We first simulate the arctic hillslopes from a stochastic space-filling network and demonstrate that the flow-path convergent properties of arctic landscape can be effectively captured from this simple model, where the simple model represents a landscape flowpath arrangement on a relatively impervious frozen soil layer. Further, we use a novel data processing algorithm to analyze landscape attributes such as slope, curvature, flow-accumulation, elevation-drops and other geomorphic properties, and show that the pattern of diffusion and advection dominated soil transport processes (diffusion/advection regime transition) in the arctic landscape is substantially different from the pattern in temperate landscapes. Our results suggest that Arctic landscapes are characterized by relatively undissected, long planar hillslopes, which convey sediment to quasi-fluvial valleys through long (~ 1 km) flow-paths. Further, we also document that broad planar hillslopes abruptly converge, forcing rapid subsurface flow accumulation at channel heads. This topographic characteristic can successfully be used to explain the position of erosion features. Finally we estimate the landscape model parameters for the arctic landscape that can be successfully used to model development and validation purposes.

Meteorologic, oceanographic, and geomorphic controls on circulation and residence time in a coral reef-lined embayment: Faga'alu Bay, American Samoa

NASA Astrophysics Data System (ADS)

Storlazzi, C. D.; Cheriton, O. M.; Messina, A. M.; Biggs, T. W.

2018-06-01

Water circulation over coral reefs can determine the degree to which reef organisms are exposed to the overlying waters, so understanding circulation is necessary to interpret spatial patterns in coral health. Because coral reefs often have high geomorphic complexity, circulation patterns and the duration of exposure, or "local residence time" of a water parcel, can vary substantially over small distances. Different meteorologic and oceanographic forcings can further alter residence time patterns over reefs. Here, spatially dense Lagrangian surface current drifters and Eulerian current meters were used to characterize circulation patterns and resulting residence times over different regions of the reefs in Faga'alu Bay, American Samoa, during three distinct forcing periods: calm, strong winds, and large waves. Residence times varied among different geomorphic zones of the reef and were reflected in the spatially varying health of the corals across the embayment. The relatively healthy, seaward fringing reef consistently had the shortest residence times, as it was continually flushed by wave breaking at the reef crest, whereas the degraded, sheltered, leeward fringing reef consistently had the longest residence times, suggesting this area is more exposed to land-based sources of pollution. Strong wind forcing resulted in the longest residence times by pinning the water in the bay, whereas large wave forcing flushed the bay and resulted in the shortest residence times. The effect of these different forcings on residence times was fairly consistent across all reef geomorphic zones, with the shift from wind to wave forcing shortening mean residence times by approximately 50%. Although ecologically significant to the coral organisms in the nearshore reef zones, these shortened residence times were still 2-3 times longer than those associated with the seaward fringing reef across all forcing conditions, demonstrating how the geomorphology of a reef environment sets a first-order control on reef health.

Wet meadow ecosystems and the longevity of biologically-mediated geomorphic features

NASA Astrophysics Data System (ADS)

Nash, C.; Grant, G.; O'Connor, J. E.

2016-12-01

Upland meadows represent a ubiquitous feature of montane landscapes in the U.S. West and beyond. Characterized by flat valley floors flanked by higher-gradient hillslopes, these meadows are important features, both for the diverse ecosystems they support but also because they represent depositional features in what is primarily an erosional environment. As such, they serve as long-term chronometers of both geological and ecological processes in a portion of the landscape where such records are rare, and provide a useful microcosm for exploring many of the questions motivating critical zone science. Specifically, meadows can offer insights into questions regarding the longevity of theses biologically-mediated landscapes, and the geomorphic thresholds associated with transitions between metastable landscape states. Though categorically depositional, wet meadows have been shown to rapidly shift into erosional landscapes characterized by deep arroyos, declining water tables, and sparse, semi-arid ecosystems. Numerous hypotheses have been proposed explaining this shift: intensive ungulate usage, removal of beaver, climatic shifts, and intrinsic geomorphic evolution. Even less is known about the mechanisms controlling the construction of these meadow features. Evidence seems to suggest these channels oscillate between two metastable conditions: deeply incised, single-threaded channels and sheet-flow dominated valley-spanning wetlands. We present new evidence exploring the subsurface architecture of wet meadows and the bidirectional process cascades potentially responsible for their temporal evolution. Using a combination of near surface geophysical techniques and detailed stratigraphic descriptions of incised and un-incised meadows throughout the Silvies River Basin, OR, we examine mechanisms responsible both for the construction of these features and their apparently rapid transition from depositional to erosional. Our investigation focuses specifically on potential interactions between biogenic and geomorphic features and processes: beaver meadow complexes, downed wood, and the accumulation of senescent vegetation to form thick peat mounds. These observations have broad potential utility to help guide meadow restoration efforts across the Western U.S.

Fluvial processes and vegetation - Glimpses of the past, the present, and perhaps the future

USGS Publications Warehouse

Osterkamp, W.R.; Hupp, C.R.

2010-01-01

Most research before 1960 into interactions among fluvial processes, resulting landforms, and vegetation was descriptive. Since then, however, research has become more detailed and quantitative permitting numerical modeling and applications including agricultural-erosion abatement and rehabilitation of altered bottomlands. Although progress was largely observational, the empiricism increasingly yielded to objective recognition of how vegetation interacts with and influences geomorphic process. A review of advances relating fluvial processes and vegetation during the last 50 years centers on hydrologic reconstructions from tree rings, plant indicators of flow- and flood-frequency parameters, hydrologic controls on plant species, regulation of sediment movement by vegetation, vegetative controls on mass movement, and relations between plant cover and sediment movement. Extension of present studies of vegetation as a regulator of bottomland hydrologic and geomorphic processes may become markedly more sophisticated and widespread than at present. Research emphases that are likely to continue include vegetative considerations for erosion modeling, response of riparian-zone forests to disturbance such as dams and water diversion, the effect of vegetation on channel and bottomland dynamics, and rehabilitation of stream corridors. Research topics that presently are receiving attention are the effect of woody vegetation on the roughness of stream corridors and, hence, processes of flood conveyance and flood-plain sedimentation, the development of a theoretical basis for rehabilitation projects as opposed to fully empirical approaches, the effect of invasive plant species on the dynamics of bottomland vegetation, the quantification of below-surface biomass and related soil-stability factors for use in erosion-prediction models, and the effect of impoundments on downstream narrowing of channels and accompanying encroachment of vegetation. Bottomland vegetation partially controls and is controlled by fluvial-geomorphic processes. The purposes of this paper are to identify and review investigations that have related vegetation to bottomland features and processes, to distinguish the present status of these investigations, and to anticipate future research into how hydrologic and fluvial-geomorphic processes of bottomlands interact with vegetation.

Geomorphic, hydrologic, and erosion data for selected reclaimed hillslopes, the Seneca II Mine, Routt County, Colorado, October 1988 - July 1990

USGS Publications Warehouse

Elliott, J.G.

1993-01-01

Geomorphic, hydrologic, and erosion data were collected from five reclaimed hillslopes at the Seneca II mine near Hayden, Colorado. Hillslope surveys were used to determine hillslope lengths, which range from 670 to 1,280 ft, and hillslope gradients, which range from 0.17 to 0.23 ft/ft (17 to 23 percent). Elevations in the study area range from 6,890 to 7,140 feet and hillslope aspect generally is west or south. Mean total vegetation cover ranges from 74 to 91 percent. Total monthly precipitation for December 1988 through May 1990 was computed from daily measurements made with weighing-bucket precipitation gages. Several snowpack measurements were made during 2 winters. Volumetric soil-water content was determined at incremental depths using a neutron probe and in the upper 11.8 in of soil using a time-domain reflectometer. Active and recent soil erosion was indicated by the presence of rills. Rill density (the sum of rill lengths/unit area) was computed at 50-feet intervals along each hillslope study area. Differences in soil-surface elevations between September or October 1989 and June 1990 were determined with an erosion frame and replicate soil-surface surveys at 16 erosion-study plots.

Geomorphic control of landscape carbon accumulation

USGS Publications Warehouse

Rosenbloom, N.A.; Harden, J.W.; Neff, J.C.; Schimel, D.S.

2006-01-01

We use the CREEP process-response model to simulate soil organic carbon accumulation in an undisturbed prairie site in Iowa. Our primary objectives are to identify spatial patterns of carbon accumulation, and explore the effect of erosion on basin-scale C accumulation. Our results point to two general findings. First, redistribution of soil carbon by erosion results in a net increase in basin-wide carbon storage relative to a noneroding environment. Landscape-average mean residence times are increased in an eroding landscape owing to the burial/preservation of otherwise labile C. Second, field observations taken along a slope transect may overlook significant intraslope variations in carbon accumulation. Spatial patterns of modeled deep C accumulation are complex. While surface carbon with its relatively short equilibration time is predictable from surface properties, deep carbon is strongly influenced by the landscape's geomorphic and climatic history, resulting in wide spatial variability. Convergence and divergence associated with upland swales and interfluves result in bimodal carbon distributions in upper and mid slopes; variability in carbon storage within modeled mid slopes was as high as simulated differences between erosional shoulders and depositional valley bottoms. The bimodality of mid-slope C variability in the model suggests that a three-dimensional sampling strategy is preferable over the traditional two-dimensional analog or "catena" approach. Copyright 2006 by the American Geophysical Union.

Estimating discharge in rivers using remotely sensed hydraulic information

USGS Publications Warehouse

Bjerklie, D.M.; Moller, D.; Smith, L.C.; Dingman, S.L.

2005-01-01

A methodology to estimate in-bank river discharge exclusively from remotely sensed hydraulic data is developed. Water-surface width and maximum channel width measured from 26 aerial and digital orthophotos of 17 single channel rivers and 41 SAR images of three braided rivers were coupled with channel slope data obtained from topographic maps to estimate the discharge. The standard error of the discharge estimates were within a factor of 1.5-2 (50-100%) of the observed, with the mean estimate accuracy within 10%. This level of accuracy was achieved using calibration functions developed from observed discharge. The calibration functions use reach specific geomorphic variables, the maximum channel width and the channel slope, to predict a correction factor. The calibration functions are related to channel type. Surface velocity and width information, obtained from a single C-band image obtained by the Jet Propulsion Laboratory's (JPL's) AirSAR was also used to estimate discharge for a reach of the Missouri River. Without using a calibration function, the estimate accuracy was +72% of the observed discharge, which is within the expected range of uncertainty for the method. However, using the observed velocity to calibrate the initial estimate improved the estimate accuracy to within +10% of the observed. Remotely sensed discharge estimates with accuracies reported in this paper could be useful for regional or continental scale hydrologic studies, or in regions where ground-based data is lacking. ?? 2004 Elsevier B.V. All rights reserved.

Effects of Urbanization on the Flow Regimes of Semi-Arid Southern California Streams

NASA Astrophysics Data System (ADS)

Hawley, R. J.; Bledsoe, B. P.; Stein, E. D.

2010-12-01

Stream channel erosion and associated habitat degradation are pervasive in streams draining urban areas in the southwestern US. The prevalence of these impacts results from the inherent sensitivity of streams in semi-arid climates to changes in flow and sediment regimes, and past inattention to management of geomorphically effective flows. Addressing this issue is difficult due to the lack of data linking ranges of flow (from small to large runoff events) to geomorphic channel response. Forty-three U. S. Geological Survey gages with record lengths greater than ~15 yrs and watershed areas less than ~250 square kilometers were used to empirically model the effects of urbanization on streams in southern California. The watersheds spanned a gradient of urban development and ranged from 0 to 23% total impervious area in 2001. With little flow control at the subdivision scale to date, most impervious area in the region is relatively well-connected to surface-drainage networks. Consequently, total impervious area was an effective surrogate for urbanization, and emerged as a significant (p < 0.05) predictor of instantaneous peak-flow rates at the 1.5- and 2-yr recurrence intervals, with decreasing significance and influence at higher return periods. For example, peak factors for a watershed with 20% imperviousness were ~10, 6, and 2 for the 1.5-, 2-, and 5-yr flows, respectively, with no discernable influence at flows greater than the 10-yr event. Most importantly with respect to geomorphic response, urbanization extent was a significant predictor of duration density functions, which integrate the magnitude and duration of mean daily discharges. This approach expands on previous scaling procedures to produce histogram-style cumulative flow duration graphs for ungaged sites based on urbanization extent and other watershed descriptors. Urbanization resulted in proportionally-longer durations of all geomorphically-effective flows, with a more pronounced effect on the durations of moderate flows. For example, an average watershed from the study domain with ~20% imperviousness could experience five times as many days of mean daily flows on the order of 100 cfs (3 cubic meters per second) and approximately three times as many days on the order of 1,000 cfs (30 cubic meters per second) relative to the undeveloped setting. Increased duration of sediment-transporting flows is a primary driver of accelerated changes in channel form that are often concurrent with urbanization throughout southern California, particularly in unconfined, fine-grained geomorphic settings. Consequently, urbanization seems to serve as a potential catalyst that can send previously functioning habitats onto degradational trajectories that are typically arrested via concrete/riprap trapezoidal flood conveyance channels with little ecological/geomorphic function.

Estimation of the long-term slip, surface uplift and block rotation along the northern strand of the North Anatolian Fault Zone: Inferences from geomorphology of the Almacık Block

NASA Astrophysics Data System (ADS)

Yıldırım, Cengiz; Tüysüz, Okan

2017-11-01

The Almacık Block is one of the key morphotectonic units in the eastern Marmara Region associated with the long-term slip partitioning within the North Anatolian Fault Zone (NAFZ). In this study, we provide new geomorphic reconstructions of offset drainage basins, morphometric analysis of topography, and longitudinal profiles of the rivers crossing different flanks of the Almacık Block. Our geomorphic reconstructions of offset drainage basins along the Hendek and Karadere faults imply mean offsets of 2.3 ± 0.4 km and 8.4 ± 0.7 km, respectively, during the Quaternary. Our dataset also imply that slip partitioning occurs in a broader zone than previously proposed, and that the total 10.7 ± 0.6 km offset along the Hendek and Karadere faults of the northern strand must be taken into account for long-term slip partitioning in the Eastern Marmara Region. Together with previously suggested 10 km offset along the southern strand (Yaltırak, 2002), 16 ± 1.0 km offset along the middle strand (Özalp et al., 2013) and the 52 ± 1.0 km offset along the Mudurnu Segment of the northern strand (Akbayram et al., 2016) our newly proposed geomorphic markers raise the cumulative offset in the eastern Marmara region associated with the NAF to 89 ± 1.0 km since the Latest Pliocene - Quaternary. In addition to these lateral displacements, our morphometric analysis and longitudinal profiles of the rivers imply up to 1130 ± 130 m surface uplift of the Almacık Block as a combined result of vertical displacement within the deformation zone of the northern strand of the NAFZ. Finally, by assuming that river basins act as passive deformation markers, our basin azimuth analyses imply 20° ± 2° clockwise rotation of the Almacık Block associated with the NAFZ.

Balancing hydropower production and river bed incision in operating a run-of-river hydropower scheme along the River Po

NASA Astrophysics Data System (ADS)

Denaro, Simona; Dinh, Quang; Bizzi, Simone; Bernardi, Dario; Pavan, Sara; Castelletti, Andrea; Schippa, Leonardo; Soncini-Sessa, Rodolfo

2013-04-01

Water management through dams and reservoirs is worldwide necessary to support key human-related activities ranging from hydropower production to water allocation, and flood risk mitigation. Reservoir operations are commonly planned in order to maximize these objectives. However reservoirs strongly influence river geomorphic processes causing sediment deficit downstream, altering the flow regime, leading, often, to process of river bed incision: for instance the variations of river cross sections over few years can notably affect hydropower production, flood mitigation, water supply strategies and eco-hydrological processes of the freshwater ecosystem. The river Po (a major Italian river) has experienced severe bed incision in the last decades. For this reason infrastructure stability has been negatively affected, and capacity to derive water decreased, navigation, fishing and tourism are suffering economic damages, not to mention the impact on the environment. Our case study analyzes the management of Isola Serafini hydropower plant located on the main Po river course. The plant has a major impact to the geomorphic river processes downstream, affecting sediment supply, connectivity (stopping sediment upstream the dam) and transport capacity (altering the flow regime). Current operation policy aims at maximizing hydropower production neglecting the effects in term of geomorphic processes. A new improved policy should also consider controlling downstream river bed incision. The aim of this research is to find suitable modeling framework to identify an operating policy for Isola Serafini reservoir able to provide an optimal trade-off between these two conflicting objectives: hydropower production and river bed incision downstream. A multi-objective simulation-based optimization framework is adopted. The operating policy is parameterized as a piecewise linear function and the parameters optimized using an interactive response surface approach. Global and local response surface are comparatively assessed. Preliminary results show that a range of potentially interesting trade-off policies exist able to better control river bed incision downstream without significantly decreasing hydropower production.

Ecosystem effects of environmental flows: Modelling and experimental floods in a dryland river

USGS Publications Warehouse

Shafroth, P.B.; Wilcox, A.C.; Lytle, D.A.; Hickey, J.T.; Andersen, D.C.; Beauchamp, Vanessa B.; Hautzinger, A.; McMullen, L.E.; Warner, A.

2010-01-01

Successful environmental flow prescriptions require an accurate understanding of the linkages among flow events, geomorphic processes and biotic responses. We describe models and results from experimental flow releases associated with an environmental flow program on the Bill Williams River (BWR), Arizona, in arid to semiarid western U.S.A. Two general approaches for improving knowledge and predictions of ecological responses to environmental flows are: (1) coupling physical system models to ecological responses and (2) clarifying empirical relationships between flow and ecological responses through implementation and monitoring of experimental flow releases. We modelled the BWR physical system using: (1) a reservoir operations model to simulate reservoir releases and reservoir water levels and estimate flow through the river system under a range of scenarios, (2) one- and two-dimensional river hydraulics models to estimate stage-discharge relationships at the whole-river and local scales, respectively, and (3) a groundwater model to estimate surface- and groundwater interactions in a large, alluvial valley on the BWR where surface flow is frequently absent. An example of a coupled, hydrology-ecology model is the Ecosystems Function Model, which we used to link a one-dimensional hydraulic model with riparian tree seedling establishment requirements to produce spatially explicit predictions of seedling recruitment locations in a Geographic Information System. We also quantified the effects of small experimental floods on the differential mortality of native and exotic riparian trees, on beaver dam integrity and distribution, and on the dynamics of differentially flow-adapted benthic macroinvertebrate groups. Results of model applications and experimental flow releases are contributing to adaptive flow management on the BWR and to the development of regional environmental flow standards. General themes that emerged from our work include the importance of response thresholds, which are commonly driven by geomorphic thresholds or mediated by geomorphic processes, and the importance of spatial and temporal variation in the effects of flows on ecosystems, which can result from factors such as longitudinal complexity and ecohydrological feedbacks. ?? Published 2009.

Sedimentation, volcanism, and ancestral lakes in the Valles Marineris: Clues from topography

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.; Isbell, N. K.; Howington-Kraus, A.

1993-01-01

Compilation of a simplified geologic/geomorphic map onto a digital terrain model of Valles Marineris has permitted quantitative evaluations of topographic parameters. The study showed that, if their interior layered deposits are lacustrine, the ancestral Valles Marineris must have consisted of isolated basins. If, on the other hand, the troughs were interconnected as they are today, the deposits are most likely to volcanic origin, and the mesas in the peripheral troughs may be table mountains. The material eroded from the trough walls was probably not sufficient to form all of the interior layered deposits, but it may have contributed significantly to their formation.

Geomorphology and Tectonics at the Intersection of Silurian and Death Valleys, Southern California - 2005 Guidebook Pacific Cell Friends of the Pleistocene

USGS Publications Warehouse

Miller, David M.; Valin, Zenon C.

2007-01-01

This publication describes results from new regional and detailed surficial geologic mapping, combined with geomorphologic, geochronologic, and tectonic studies, in Silurian Valley and Death Valley, California. The studies address a long-standing problem, the tectonic and geomorphic evolution of the intersection between three regional tectonic provinces: the eastern California shear zone, the Basin and Range region of southern Nevada and adjacent California, and the eastern Mojave Desert region. The chapters represent work presented on the 2005 Friends of the Pleistocene field trip and meeting as well as the field trip road log.

HCMM: Soil moisture in relation to geologic structure and lithology, northern California. [Northern Coast Range, Sacramento Valley, and the Modoc Plateau

NASA Technical Reports Server (NTRS)

Rich, E. I. (Principal Investigator)

1981-01-01

Heat capacity mapping mission images of about 80,000 sq km in northern California were qualitatively evaluated for usefulness in regional geologic investigations of structure and lithology. The thermal characteristics recorded vary among the several geomorphic provinces and depend chiefly on the topographic expression and vegetation cover. Identification of rock types, or groups of rock types, was most successfully carried out within the semiarid parts of the region; however, extensive features, such as faults, folds and volcanic fields could be delineated. Comparisons of seasonally obtained HCMM images are of limited value except in semiarid regions.

Warming early Mars with carbon dioxide clouds that scatter infrared radiation.

PubMed

Forget, F; Pierrehumbert, R T

1997-11-14

Geomorphic evidence that Mars was warm enough to support flowing water about 3.8 billion years ago presents a continuing enigma that cannot be explained by conventional greenhouse warming mechanisms. Model calculations show that the surface of early Mars could have been warmed through a scattering variant of the greenhouse effect, resulting from the ability of the carbon dioxide ice clouds to reflect the outgoing thermal radiation back to the surface. This process could also explain how Earth avoided an early irreversible glaciation and could extend the size of the habitable zone on extrasolar planets around stars.