Water Quality Outlet Works Prototype Tests, Warm Springs Dam Dry Creek, Russian River Basin Sonoma County, California

DTIC Science & Technology

1989-03-01

34.4* TECHNICAL REPORT HL-89-4 WATER QUALITY OUTLET WORKS PROTOTYPE TESTS, WARM SPRINGS DAM DRY CREEK, RUSSIAN RIVER BASIN AD-A207 058 SONOMA COUNTY , CALIFORNIA...Clawflcation) [7 Water Quality Outlet Works Prototype Tests, Warm Springs Dam, Dry Creek, Russian River Basin, Sonoma County , California 12. PERSONAL...Cointogobvil Be,,pesso Figur 1. iciniyama Pealm WATER QUALITY OUTLET WORKS PROTOTYPE TESTS WARM SPRINGS DAM, DRY CREEK, RUSSIAN RIVER BASIN SONOMA COUNTY , CALIFORNIA

WARM SPRINGS CREEK GEOTHERMAL STUDY, BLAIN COUNTY IDAHO, 1987

EPA Science Inventory

In the Warm Springs Creek drainage near Ketchum, Idaho (17040219), a leaking pipeline coveys geothermal water through the valley to heat nearby homes as well as to supply a resorts swimming pool. Several domestic wells in close proximity to this line have exhibited increasing fl...

Plant phenological synchrony increases under rapid within-spring warming.

PubMed

Wang, Cong; Tang, Yanhong; Chen, Jin

2016-05-05

Phenological synchrony influences many ecological processes. Recent climate change has altered the synchrony of phenology, but little is known about the underlying mechanisms. Here using in situ phenological records from Europe, we found that the standard deviation (SD, as a measure of synchrony) of first leafing day (FLD) and the SD of first flowering day (FFD) among local plants were significantly smaller in the years and/or in the regions with a more rapid within-spring warming speed (WWS, the linear slope of the daily mean temperature against the days during spring, in (o)C/day) with correlation coefficients of -0.75 and -0.48 for FLD and -0.55 and -0.23 for FFD. We further found that the SDs of temperature sensitivity of local plants were smaller under the rapid WWS conditions with correlation coefficients of -0.46 and -0.33 for FLD and FFD respectively. This study provides the first evidence that the within-season rate of change of the temperature but not the magnitude determines plant phenological synchrony. It implies that temporally, the asymmetric seasonal climatic warming may decrease the synchrony via increasing WWS, especially in arctic regions; spatially, plants in coastal and low latitude areas with low WWS would have more diverse spring phenological traits.

Water resources of the Warm Springs Indian Reservation, Oregon

USGS Publications Warehouse

Robison, J.H.; Laenen, Antonius

1976-01-01

Water-resources data for the 1,000-square-mile Warm Springs Indian Reservation in north-central Oregon were obtained and evaluated. The area is bounded on the west by the crest of the Cascade Range and on the south and east by the Metolius and Deschutes Rivers. The mountainous western part is underlain by young volcanic rocks, and the plateaus and valleys of the eastern part are underlain by basalt, tuff, sand, and gravel of Tertiary and Quaternary ages. There are numerous springs, some developed for stock use, and about 50 domestic and community wells; yields are small, ranging from less than 1 to as much as 25 gallons per minute. Chemical quality of most ground water is suitable for stock or human consumption and for irrigation. Average flows of the Warm Springs River, Metolius River, and Deschutes River are 440, 1,400, and 4,040 cubic feet per second (cfs), respectively. Shitike Creek, which has an average flow of 108 cfs had a peak of 4,000 cfs in January 1974. Most streams have fewer than 100 milligrams per liter (mg/liter) of dissolved solids. Chemical and biological quality of the mountain lakes is also good; of 10 lakes studied, all had fewer than 50 mg/liter of dissolved solids and none had measurable fecal coliform bacteria. (Woodard-USGS)

Declining global warming effects on the phenology of spring leaf unfolding.

PubMed

Fu, Yongshuo H; Zhao, Hongfang; Piao, Shilong; Peaucelle, Marc; Peng, Shushi; Zhou, Guiyun; Ciais, Philippe; Huang, Mengtian; Menzel, Annette; Peñuelas, Josep; Song, Yang; Vitasse, Yann; Zeng, Zhenzhong; Janssens, Ivan A

2015-10-01

Earlier spring leaf unfolding is a frequently observed response of plants to climate warming. Many deciduous tree species require chilling for dormancy release, and warming-related reductions in chilling may counteract the advance of leaf unfolding in response to warming. Empirical evidence for this, however, is limited to saplings or twigs in climate-controlled chambers. Using long-term in situ observations of leaf unfolding for seven dominant European tree species at 1,245 sites, here we show that the apparent response of leaf unfolding to climate warming (ST, expressed in days advance of leaf unfolding per °C warming) has significantly decreased from 1980 to 2013 in all monitored tree species. Averaged across all species and sites, ST decreased by 40% from 4.0 ± 1.8 days °C(-1) during 1980-1994 to 2.3 ± 1.6 days °C(-1) during 1999-2013. The declining ST was also simulated by chilling-based phenology models, albeit with a weaker decline (24-30%) than observed in situ. The reduction in ST is likely to be partly attributable to reduced chilling. Nonetheless, other mechanisms may also have a role, such as 'photoperiod limitation' mechanisms that may become ultimately limiting when leaf unfolding dates occur too early in the season. Our results provide empirical evidence for a declining ST, but also suggest that the predicted strong winter warming in the future may further reduce ST and therefore result in a slowdown in the advance of tree spring phenology.

Modeling fluid flow and heat transfer at Basin and Range faults: preliminary results for Leach hot springs, Nevada

USGS Publications Warehouse

López, Dina L.; Smith, Leslie; Storey, Michael L.; Nielson, Dennis L.

1994-01-01

The hydrothermal systems of the Basin and Range Province are often located at or near major range bounding normal faults. The flow of fluid and energy at these faults is affected by the advective transfer of heat and fluid from an to the adjacent mountain ranges and valleys, This paper addresses the effect of the exchange of fluid and energy between the country rock, the valley fill sediments, and the fault zone, on the fluid and heat flow regimes at the fault plane. For comparative purposes, the conditions simulated are patterned on Leach Hot Springs in southern Grass Valley, Nevada. Our simulations indicated that convection can exist at the fault plane even when the fault is exchanging significant heat and fluid with the surrounding country rock and valley fill sediments. The temperature at the base of the fault decreased with increasing permeability of the country rock. Higher groundwater discharge from the fault and lower temperatures at the base of the fault are favored by high country rock permabilities and fault transmissivities. Preliminary results suggest that basal temperatures and flow rates for Leach Hot Springs can not be simulated with a fault 3 km deep and an average regional heat flow of 150 mW/m2 because the basal temperature and mass discharge rates are too low. A fault permeable to greater depths or a higher regional heat flow may be indicated for these springs.

Global warming leads to more uniform spring phenology across elevations.

PubMed

Vitasse, Yann; Signarbieux, Constant; Fu, Yongshuo H

2018-01-30

One hundred years ago, Andrew D. Hopkins estimated the progressive delay in tree leaf-out with increasing latitude, longitude, and elevation, referred to as "Hopkins' bioclimatic law." What if global warming is altering this well-known law? Here, based on ∼20,000 observations of the leaf-out date of four common temperate tree species located in 128 sites at various elevations in the European Alps, we found that the elevation-induced phenological shift (EPS) has significantly declined from 34 d⋅1,000 m -1 conforming to Hopkins' bioclimatic law in 1960, to 22 d⋅1,000 m -1 in 2016, i.e., -35%. The stronger phenological advance at higher elevations, responsible for the reduction in EPS, is most likely to be connected to stronger warming during late spring as well as to warmer winter temperatures. Indeed, under similar spring temperatures, we found that the EPS was substantially reduced in years when the previous winter was warmer. Our results provide empirical evidence for a declining EPS over the last six decades. Future climate warming may further reduce the EPS with consequences for the structure and function of mountain forest ecosystems, in particular through changes in plant-animal interactions, but the actual impact of such ongoing change is today largely unknown.

Characterizations of geothermal springs along the Moxi deep fault in the western Sichuan plateau, China

NASA Astrophysics Data System (ADS)

Qi, Jihong; Xu, Mo; An, Chengjiao; Wu, Mingliang; Zhang, Yunhui; Li, Xiao; Zhang, Qiang; Lu, Guoping

2017-02-01

Abundant geothermal springs occur along the Moxi fault located in western Sichuan Province (the eastern edge of the Qinghai-Tibet plateau), highlighted by geothermal water outflow with an unusually high temperature of 218 °C at 21.5 MPa from a 2010-m borehole in Laoyulin, Kangding. Earthquake activity occurs relatively more frequently in the region and is considered to be related to the strong hydrothermal activity. Geothermal waters hosted by a deep fault may provide evidence regarding the deep underground; their aqueous chemistry and isotopic information can indicate the mechanism of thermal springs. Cyclical variations of geothermal water outflows are thought to work under the effect of solid earth tides and can contribute to understanding conditions and processes in underground geo-environments. This paper studies the origin and variations of the geothermal spring group controlled by the Moxi fault and discusses conditions in the deep ground. Flow variation monitoring of a series of parameters was performed to study the geothermal responses to solid tides. Geothermal reservoir temperatures are evaluated with Na-K-Mg data. The abundant sulfite content, dissolved oxygen (DO) and oxidation-reduction potential (ORP) data are discussed to study the oxidation-reduction states. Strontium isotopes are used to trace the water source. The results demonstrate that geothermal water could flow quickly through the Moxi fault the depth of the geothermal reservoir influences the thermal reservoir temperature, where supercritical hot water is mixed with circulating groundwater and can reach 380 °C. To the southward along the fault, the circulation of geothermal waters becomes shallower, and the waters may have reacted with metamorphic rock to some extent. Our results provide a conceptual deep heat source model for geothermal flow and the reservoir characteristics of the Moxi fault and indicate that the faulting may well connect the deep heat source to shallower depths. The

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.

Warm Springs: People of the Community Create Their Own Museum.

ERIC Educational Resources Information Center

Patt, Olney, Jr.

1995-01-01

Since 1974, Paiute, Wasco, and Warm Springs leaders have invested over $850,000 to purchase more than 2,000 artifacts and 2,500 archival photographs and documents for a museum. Addresses the relevance of preserving cultural artifacts, the importance of finding young apprentices to carry on crafts, and the significance of preserving native…

San Andreas fault geometry at Desert Hot Springs, California, and its effects on earthquake hazards and groundwater

USGS Publications Warehouse

Catchings, R.D.; Rymer, M.J.; Goldman, M.R.; Gandhok, G.

2009-01-01

The Mission Creek and Banning faults are two of the principal strands of the San Andreas fault zone in the northern Coachella Valley of southern California. Structural characteristics of the faults affect both regional earthquake hazards and local groundwater resources. We use seismic, gravity, and geological data to characterize the San Andreas fault zone in the vicinity of Desert Hot Springs. Seismic images of the upper 500 m of the Mission Creek fault at Desert Hot Springs show multiple fault strands distributed over a 500 m wide zone, with concentrated faulting within a central 200 m wide area of the fault zone. High-velocity (up to 5000 m=sec) rocks on the northeast side of the fault are juxtaposed against a low-velocity (6.0) earthquakes in the area (in 1948 and 1986) occurred at or near the depths (~10 to 12 km) of the merged (San Andreas) fault. Large-magnitude earthquakes that nucleate at or below the merged fault will likely generate strong shaking from guided waves along both fault zones and from amplified seismic waves in the low-velocity basin between the two fault zones. The Mission Creek fault zone is a groundwater barrier with the top of the water table varying by 60 m in depth and the aquifer varying by about 50 m in thickness across a 200 m wide zone of concentrated faulting.

Numerical investigation on the implications of spring temperature and discharge rate with respect to the geothermal background in a fault zone

NASA Astrophysics Data System (ADS)

Jiang, Zhenjiao; Xu, Tianfu; Mariethoz, Gregoire

2018-04-01

Geothermal springs are some of the most obvious indicators of the existence of high-temperature geothermal resources in the subsurface. However, geothermal springs can also occur in areas of low average subsurface temperatures, which makes it difficult to assess exploitable zones. To address this problem, this study quantitatively analyzes the conditions associated with the formation of geothermal springs in fault zones, and numerically investigates the implications that outflow temperature and discharge rate from geothermal springs have on the geothermal background in the subsurface. It is concluded that the temperature of geothermal springs in fault zones is mainly controlled by the recharge rate from the country rock and the hydraulic conductivity in the fault damage zone. Importantly, the topography of the fault trace on the land surface plays an important role in determining the thermal temperature. In fault zones with a permeability higher than 1 mD and a lateral recharge rate from the country rock higher than 1 m3/day, convection plays a dominant role in the heat transport rather than thermal conduction. The geothermal springs do not necessarily occur in the place having an abnormal geothermal background (with the temperature at certain depth exceeding the temperature inferred by the global average continental geothermal gradient of 30 °C/km). Assuming a constant temperature (90 °C here, to represent a normal geothermal background in the subsurface at a depth of 3,000 m), the conditions required for the occurrence of geothermal springs were quantitatively determined.

IRETHERM: Magnetotelluric Assessment of Geothermal Energy Potential of Hydrothermal Aquifer, Radiothermal Granite and Warm Spring Targets in Ireland

NASA Astrophysics Data System (ADS)

Jones, Alan G.; Muller, Mark; Fullea, Javier; Vozar, Jan; Blake, Sarah; Delhaye, Robert; Farrell, Thomas

2013-04-01

IRETHERM (www.iretherm.ie) is an academic-government-industry, collaborative research project, funded by Science Foundation Ireland, with the overarching objective of developing a holistic understanding of Ireland's low-enthalpy geothermal energy potential through integrated modelling of new and existing geophysical and geological data. With the exception of Permo-Triassic basins in Northern Ireland, hosting geothermal aquifers of promising but currently poorly-defined potential, rocks with high primary porosity have not been identified elsewhere. Whether any major Irish shear zones/faults might host a geothermal aquifer at depth is also unknown, although clusters of warm-springs in the vicinity of two major shear zones are promising. IRETHERM's objectives over a four-year period are to: (i) Develop multi-parameter geophysical modelling and interpretation software tools that will enhance our ability to explore for and assess deep aquifers and granitic intrusions. (ii) Model and understand temperature variations in the upper-crust. Firstly, by building a 3-D model of crustal heat-production based on geochemical analysis of surface, borehole and mid- to lower-crustal xenolith samples. Secondly, by modelling, using a fully self-consistent 3-D approach, observed surface heat-flow variation as a function of variation in the structure and thermal properties of the crust and lithosphere, additionally constrained by surface elevation, geoid, gravity, seismic and magnetotelluric (MT) data. (iii) Test a strategic set of eight "type" geothermal targets with a systematic program of electromagnetic surveys (MT, CSEM) across ten target areas. During 2012, IRETHERM collected over 220 MT/AMT sites in the investigation of a range of different geothermal target types. Here we present preliminary electrical resistivity modelling results for each target investigated and discuss the implications of the models for geothermal energy potential: 1. Rathlin Basin The only sedimentary strata

Physical mechanisms of spring and summertime drought related with the global warming over the northern America

NASA Astrophysics Data System (ADS)

Choi, W.; Kim, K. Y.

2017-12-01

Drought during the growing season (spring through summer) is severe natural hazard in the large cropland over the northern America. It is important to understand how the drought is related with the global warming and how it will change in the future. This study aims to investigate the physical mechanism of global warming impact on the spring and summertime drought over the northern America using Cyclostationary Empirical Orthogonal Function (CSEOF) analysis. The Northern Hemisphere surface warming, the most dominant mode of the surface air temperature, has resulted in decreased relative humidity and precipitation over the mid-latitude region of North America. For the viewpoint of atmospheric water demand, soil moisture and evaporation have also decreased significantly, exacerbating vulnerability of drought. These consistent features of changes in water demand and supply related with the global warming can provide a possibility of credible insight for future drought change.

Log and data from a trench across the Hubbell Spring Fault Zone, Bernalillo County, New Mexico

USGS Publications Warehouse

Personius, S.F.; Eppes, M.C.; Mahan, S.A.; Love, D.W.; Mitchell, D.K.; Murphy, Anne

2000-01-01

This report contains field and laboratory data resulting from a trench study of the Hubbell Spring fault zone near Albuquerque, New Mexico. This trench was excavated in September, 1997, as part of earthquake hazards investigations of Quaternary faults in the Albuquerque metropolitan area. The trench was excavated across the youngest of several fault strands near the northern end of the Hubbell Spring fault zone. The site is located on Pueblo of Isleta tribal lands, approximately 1 km south of the southern boundary of Kirtland Air Force Base. Thus the paleoearthquake data derived from investigations at the Hubbell Spring site will be useful in assessing potential earthquake hazards in Isleta Pueblo, Kirtland Air Force Base/Sandia National Laboratories, and the Albuquerque metropolitan area. The purpose of this report is to present a detailed trench log, a scarp profile, soils data (table 1), magnetic susceptibility data (table 2), luminescence and uranium-series ages (tables 3 and 4), and detailed unit descriptions (table 5) obtained in this investigation. S.F. Personius had primary responsibility for siting, excavating, describing, and interpreting the trench; S.A. Mahan did the luminescence dating, and James B. Paces did the uranium-series dating. M.C. Eppes and D.W. Love assisted with trench logging and mapping; and M.C. Eppes, D.K. Mitchell, and A. Murphy did the soils analyses.

Dynamic rupture models of earthquakes on the Bartlett Springs Fault, Northern California

USGS Publications Warehouse

Lozos, Julian C.; Harris, Ruth A.; Murray, Jessica R.; Lienkaemper, James J.

2015-01-01

The Bartlett Springs Fault (BSF), the easternmost branch of the northern San Andreas Fault system, creeps along much of its length. Geodetic data for the BSF are sparse, and surface creep rates are generally poorly constrained. The two existing geodetic slip rate inversions resolve at least one locked patch within the creeping zones. We use the 3-D finite element code FaultMod to conduct dynamic rupture models based on both geodetic inversions, in order to determine the ability of rupture to propagate into the creeping regions, as well as to assess possible magnitudes for BSF ruptures. For both sets of models, we find that the distribution of aseismic creep limits the extent of coseismic rupture, due to the contrast in frictional properties between the locked and creeping regions.

The thermal regime and species composition of fish and invertebrates in Kelly Warm Spring, Grand Teton National Park, Wyoming

USGS Publications Warehouse

Harper, David; Farag, Aida

2017-01-01

We evaluated the thermal regime and relative abundance of native and nonnative fish and invertebrates within Kelly Warm Spring and Savage Ditch, Grand Teton National Park, Wyoming. Water temperatures within the system remained relatively warm year-round with mean temperatures >20 °C near the spring source and >5 °C approximately 2 km downstream of the source. A total of 7 nonnative species were collected: Convict/Zebra Cichlid (Cichlasoma nigrofasciatum), Green Swordtail (Xiphophorus hellerii), Tadpole Madtom (Noturus gyrinus), Guppy (Poecilia reticulata), Goldfish (Carassius auratus), red-rimmed melania snail (Melanoides tuberculata), and American bullfrog tadpoles (Lithobates catesbeianus). Nonnative fish (Zebra Cichlids and Green Swordtails), red-rimmed melania snails, and bullfrog tadpoles dominated the upper 2 km of the system. Abundance estimates of the Zebra Cichlid exceeded 12,000 fish/km immediately downstream of the spring source. Relative abundance of native species increased movingdownstream as water temperatures attenuated with distance from the thermally warmed spring source; however, nonnative species were captured 4 km downstream from the spring. Fish diseases were prevalent in both native and nonnative fish from the Kelly Warm Spring pond. Clinostomum marginatum, a trematode parasite, was found in native species samples, and the tapeworm Diphyllobothrium dendriticum was present in samples from nonnative species. Diphyllobothrium dendriticum is rare in Wyoming. Salmonella spp. were also found in some samples of nonnative species. These bacteria are associated with aquarium fish and aquaculture and are generally not found in the wild.

Implications of Preliminary Gravity and Magnetic Surveys to the Understanding of the Bartlett Springs Fault Zone, Northern California Coast Ranges

NASA Astrophysics Data System (ADS)

Langenheim, V. E.; Jachens, R. C.; Morin, R. L.; McCabe, C. M.; Page, W. D.

2007-12-01

We use new gravity and magnetic data in the Lake Pillsbury region to help understand the geometry and character of the Bartlett Springs fault zone, one of the three main strands of the San Andreas system north of the San Francisco Bay area. We collected 153 new gravity stations in the Lake Pillsbury region that complement the sparse regional dataset and are used to estimate the thickness of Quaternary deposits in the inferred Gravelly Valley (Lake Pillsbury) pull-apart basin. We also collected 38 line-km of ground magnetic data on roads and 65 line-km by boat on the lake to supplement regional aeromagnetic surveys and to map concealed fault strands beneath the lake. The new gravity data show a significant northwest-striking gravity gradient at the base of which lies the Bartlett Springs fault zone. Superposed on this major east-facing gravity gradient is a 5 mGal low centered on Lake Pillsbury and Gravelly Valley. Inversion of the gravity field for basin thickness assuming a density contrast of 400 kg/m3 indicates the deepest part of the basin is about 400 m and located in the northern part of the valley, although the inversion lacks gravity stations within the lake. The basin is about 3 km wide and 5 km long and basin edges coincide with strands of the Bartlett Springs fault zone. Our gravity data suggest that Potter Valley, which lies between the Maacama and Bartlett Springs faults, is also as much as 400 m deep in the southern part of the valley, although additional data west of the valley would better isolate the gravity low. Geomorphologic characteristics of the valley suggest that this structure has been quiescent during the late Quaternary. Ground magnetic data are very noisy but the data in conjunction with 9.6 km-spaced NURE aeromagnetic lines suggest that regional analog aeromagnetic data flown in 1962 may suffer from location errors. The regional and NURE data show a northwest-striking magnetic high that extends across Lake Pillsbury. The northeast edge

A test for the relative strength of maternal and stock effects in spring Chinook salmon (Oncorhynchus tshawytscha) from two different hatcheries (Study site: Warm Springs Hatchery; Stocks: Warm Springs Hatchery and Carson Hatchery; Year class: 1993): Chapter 10

USGS Publications Warehouse

Wetzel, Lisa A.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Stenberg, Karl D.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

2012-01-01

An experiment was undertaken to determine the relative strength of maternal and stock effects in Chinook salmon (Oncorhynchus tshawytscha) reared in a common environment, as a companion study to our investigation of hatchery and wild Chinook salmon. Pure-strain and reciprocal crosses were made between two hatchery stocks (Carson and Warm Springs National Fish Hatcheries). The offspring were reared together in one of the hatcheries to the smolt stage, and then were transferred to a seawater rearing facility (USGS-Marrowstone Field Station). Differences in survival, growth and disease prevalence were assessed. Fish with Carson parentage grew to greater size at the hatchery and in seawater than the pure-strain Warm Springs fish, but showed higher mortality at introduction to seawater. The analyses of maternal and stock effects were inconclusive, but the theoretical responses to different combinations of maternal and stock effects may be useful in interpreting stock comparison studies.

Spring phenology at different altitudes is becoming more uniform under global warming in Europe.

PubMed

Chen, Lei; Huang, Jian-Guo; Ma, Qianqian; Hänninen, Heikki; Rossi, Sergio; Piao, Shilong; Bergeron, Yves

2018-04-26

Under current global warming, high-elevation regions are expected to experience faster warming than low-elevation regions. However, due to the lack of studies based on long-term large-scale data, the relationship between tree spring phenology and the elevation-dependent warming is unclear. Using 652k records of leaf unfolding of five temperate tree species monitored during 1951-2013 in situ in Europe, we discovered a nonlinear trend in the altitudinal sensitivity (S A , shifted days per 100 m in altitude) in spring phenology. A delayed leaf unfolding (2.7 ± 0.6 days per decade) was observed at high elevations possibly due to decreased spring forcing between 1951 and 1980. The delayed leaf unfolding at high-elevation regions was companied by a simultaneous advancing of leaf unfolding at low elevations. These divergent trends contributed to a significant increase in the S A (0.36 ± 0.07 days 100/m per decade) during 1951-1980. Since 1980, the S A started to decline with a rate of -0.32 ± 0.07 days 100/m per decade, possibly due to reduced chilling at low elevations and improved efficiency of spring forcing in advancing the leaf unfolding at high elevations, the latter being caused by increased chilling. Our results suggest that due to both different temperature changes at the different altitudes, and the different tree responses to these changes, the tree phenology has shifted at different rates leading to a more uniform phenology at different altitudes during recent decades. © 2018 John Wiley & Sons Ltd.

Preferential Flow Paths In A Karstified Spring Catchment: A Study Of Fault Zones As Conduits To Rapid Groundwater Flow

NASA Astrophysics Data System (ADS)

Kordilla, J.; Terrell, A. N.; Veltri, M.; Sauter, M.; Schmidt, S.

2017-12-01

In this study we model saturated and unsaturated flow in the karstified Weendespring catchment, located within the Leinetal graben in Goettingen, Germany. We employ the finite element COMSOL Multiphysics modeling software to model variably saturated flow using the Richards equation with a van Genuchten type parameterization. As part of the graben structure, the Weende spring catchment is intersected by seven fault zones along the main flow path of the 7400 m cross section of the catchment. As the Weende spring is part of the drinking water supply in Goettingen, it is particularly important to understand the vulnerability of the catchment and effect of fault zones on rapid transport of contaminants. Nitrate signals have been observed at the spring only a few days after the application of fertilizers within the catchment at a distance of approximately 2km. As the underlying layers are known to be highly impermeable, fault zones within the area are likely to create rapid flow paths to the water table and the spring. The model conceptualizes the catchment as containing three hydrogeological limestone units with varying degrees of karstification: the lower Muschelkalk limestone as a highly conductive layer, the middle Muschelkalk as an aquitard, and the upper Muschelkalk as another conductive layer. The fault zones are parameterized based on a combination of field data from quarries, remote sensing and literary data. The fault zone is modeled considering the fracture core as well as the surrounding damage zone with separate, specific hydraulic properties. The 2D conceptual model was implemented in COMSOL to study unsaturated flow at the catchment scale using van Genuchten parameters. The study demonstrates the importance of fault zones for preferential flow within the catchment and its effect on the spatial distribution of vulnerability.

Performance and application of a fluidized bed limestone reactor designed for control of alkalinity, hardness and pH at the Warm Springs Regional Fisheries Center

USDA-ARS?s Scientific Manuscript database

Springs serving the Warm Springs Regional Fisheries Center, Warm Springs, Georgia, have pH, alkalinity, and hardness levels that lie under the range required for successful fish propagation while free CO2 is well above allowable targets. We evaluate a pretreatment process that exploits limestone's (...

Mineral Resources of the Warm Springs Wilderness Study Area, Mohave County, Arizona

USGS Publications Warehouse

Gray, Floyd; Jachens, Robert C.; Miller, Robert J.; Turner, Robert L.; Knepper, Daniel H.; Pitkin, James A.; Keith, William J.; Mariano, John; Jones, Stephanie L.; Korzeb, Stanley L.

1986-01-01

At the request of the U.S. Bureau of Land Management, approximately 113,500 acres of the Warm Springs Wilderness Study Area (AZ-020-028/029) were evaluated for mineral resources and mineral resource potential. In this report, the area studied is referred to as the 'wilderness study area' or 'study area'; any reference to the Warm Springs Wilderness Study Area refers only to that part of the wilderness study area for which a mineral survey was requested. This study area is located in west-central Arizona. The U.S. Geological Survey and the U.S. Bureau of Mines conducted geological, geochemical, and geophysical surveys to appraise the identified mineral resources (known) and assess the mineral resource potential (undiscovered) of the study area. fieldwork for this report was carried out largely in 1986-1989. There is a 1-million short ton indicated subeconomic resource of clinoptilolite-mordenite zeolite and an additional inferred resource of 2 million short tons near McHeffy Butte, approximately 2 miles west of the study area. A perlite deposit in the southeast corner of the study area contains an inferred subeconomic resource totaling 13 million short tons. An inferred subeconomic resource of gold in 225 short tons of quartz having a grade of 0.01 8 troy ounces per short ton is present at the Cook mine, 0.5 miles west of the study area. The northwestern part of the Warm Springs Wilderness Study Area has high mineral resource potential for gold and silver. The south-central part of the study area has one area of moderate and one area north of this south-central part has low mineral resource potential for gold and silver in and near Warm Springs Canyon; the mineral resource potential for gold is also moderate in three small areas in the southern part and one area in the northeastern part of the study area. The mineral resource potential for zeolite is high for the area surrounding the McHeffy Butte prospect and for one area in the southern part of the study area. Two

Water-Surface Elevations, Discharge, and Water-Quality Data for Selected Sites in the Warm Springs Area near Moapa, Nevada

USGS Publications Warehouse

Beck, David A.; Ryan, Roslyn; Veley, Ronald J.; Harper, Donald P.; Tanko, Daron J.

2006-01-01

The U.S. Geological Survey, in cooperation with Southern Nevada Water Authority and the Nevada Division of Water Resources, operates and maintains a surface-water monitoring network of 6 continuous-record stream-flow gaging stations and 11 partial-record stations in the Warm Springs area near Moapa, Nevada. Permanent land-surface bench marks were installed within the Warm Springs area by the Las Vegas Valley Water District, the Southern Nevada Water Authority, and the U.S. Geological Survey to determine water-surface elevations at all network monitoring sites. Vertical datum elevation and horizontal coordinates were established for all bench marks through a series of Differential Global Positioning System surveys. Optical theodolite surveys were made to transfer Differential Global Positioning System vertical datums to reference marks installed at each monitoring site. The surveys were completed in June 2004 and water-surface elevations were measured on August 17, 2004. Water-surface elevations ranged from 1,810.33 feet above North American Vertical Datum of 1988 at a stream-gaging station in the Pederson Springs area to 1,706.31 feet at a station on the Muddy River near Moapa. Discharge and water-quality data were compiled for the Warm Springs area and include data provided by the U.S. Geological Survey, Nevada Division of Water Resources, U.S. Fish and Wildlife Service, Moapa Valley Water District, Desert Research Institute, and Converse Consultants. Historical and current hydrologic data-collection networks primarily are related to changes in land- and water-use activities in the Warm Springs area. These changes include declines in ranching and agricultural use, the exportation of water to other areas of Moapa Valley, and the creation of a national wildlife refuge. Water-surface elevations, discharge, and water-quality data compiled for the Warm Springs area will help identify (1) effects of changing vegetation within the former agricultural lands, (2) effects

Testing for genetic differences in survival and growth between hatchery and wild Chinook salmon from Warm Springs River, Oregon (Study sites: Warm Springs Hatchery and Little White Salmon River; Stocks: Warm Springs hatchery and Warm Springs River wild; Year classes: 1992 and 1996): Chapter 8

USGS Publications Warehouse

Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Leonetti,; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

2012-01-01

The program at Warm Springs National Fish Hatchery in north - central Oregon was initiated with spring Chinook salmon Oncorhynchus tshawytscha from the Warm Springs River. Managers included wild fish in the broodstock most years and avoided artificial selection to minimize genetic divergence from the wild founder population. We tested for genetic differences in survival and growth between the hatchery and wild populations to ascertain whether this goal has been achieved. Progeny of hatchery x hatchery (HH), hatchery female x wild male (HW), and wild x wild (WW) crosses were genetically marked at the sSOD - 1* allozyme locus and released together as unfed fry in hatchery ponds in 1992 and 1996 and in the Little White Salmon River, in south - central Washington, in 1996. Fish were evaluated to returning adult at the hatchery and over their freshwater residence of 16 months in the stream. The three crosses differed on several measures including survival to outmigration in the stream (WW>HH>HW) and juvenile growth in the hatchery (1992 year - class; WW>HW>HH); however, results may have been confounded. The genetic marks were found to differentially effect survival in a companion study (HH mark favored over WW mark; HW mark intermediate). Furthermore, HW survival in the current study was neither intermediate, as would be expect ed from additive genetic effects, nor similar to that of HH fish as would be expected from maternal effects since HW and HH fish were maternal half - siblings. Finally, the unexpected performance of HW fish precludes ruling out maternal differences between hatchery and wild mothers as the cause of differences between HH and WW fish. The key finding that survival of HH fish in a stream was 0.91 that for WW fish, indicating a small loss of fitness for natural rearing in the hatchery population, is valid only if three conditions hold: (1) any selection on the genetic marks was in the same direction as in the companion study, (2) lower survival in

Spring Temperatures Alone Cannot Explain Timing of Budburst of Boreal-Temperate Tree Species under Experimental Warming

NASA Astrophysics Data System (ADS)

Montgomery, R. A.; Reich, P. B.; Rich, R. L.; Stefanski, A.

2011-12-01

Phenology, the timing of seasonal biological events such as budburst, blossom dates, bird migration and insect development, is critical to understanding species interactions (e.g. pollination, herbivory); determines growing season length in many (i.e. seasonal) terrestrial ecosystems; and can play a role in determining species range limits. There is ample evidence that plant and animal phenology has changed in recent decades. For trees in seasonally cold climates, change is most commonly manifested as earlier budburst, likely caused by earlier onset of warming temperatures in spring. Indeed, it is often assumed that one of the major phenological responses of temperate and boreal forest ecosystems to climate change will be earlier leafing and concomitantly, a longer growing season. However, spring warming interacts with other factors such as winter chilling and photoperiod to determine timing of spring leafing. For example, warmer winters could reduce the duration and amount of chilling experienced by dormant buds and lead to delayed budburst. Despite knowledge that such interactions exist, we know little about the interactive mechanisms by which various cues influence budburst in forest tree species or whether species differ in sensitivity to those cues. This gap hinders our ability to predict phenological responses and their ecological impacts under future climate scenarios. Over the past three years, we have conducted studies of leafing phenology, germination, photosynthesis, respiration, and growth of seedlings of ten boreal-temperate tree species subjected to experimental warming using infrared heat lamps and soil heating cables. Seedlings were planted into plots receiving ambient, +1.8°C or +3.6°C temperature treatments in open, aspen forest at the Cloquet Forestry Center, Cloquet, MN, USA (46°31' N, 92°30' W, 386 m a.s.l.; 4.5°C MAT, 807 mm MAP). While all species responded to warming by advancing the absolute date of budburst, several lines of evidence

Age and source of water in springs associated with the Jacksonville Thrust Fault Complex, Calhoun County, Alabama

USGS Publications Warehouse

Robinson, James L.

2004-01-01

Water from wells and springs accounts for more than 90 percent of the public water supply in Calhoun County, Alabama. Springs associated with the Jacksonville Thrust Fault Complex are used for public water supply for the cities of Anniston and Jacksonville. The largest ground-water supply is Coldwater Spring, the primary source of water for Anniston, Alabama. The average discharge of Coldwater Spring is about 32 million gallons per day, and the variability of discharge is about 75 percent. Water-quality samples were collected from 6 springs and 15 wells in Calhoun County from November 2001 to January 2003. The pH of the ground water typically was greater than 6.0, and specific conductance was less than 300 microsiemens per centimeter. The water chemistry was dominated by calcium, carbonate, and bicarbonate ions. The hydrogen and oxygen isotopic composition of the water samples indicates the occurrence of a low-temperature, water-rock weathering reaction known as silicate hydrolysis. The residence time of the ground water, or ground-water age, was estimated by using analysis of chlorofluorocarbon, sulfur hexafluoride, and regression modeling. Estimated ground-water ages ranged from less than 10 to approximately 40 years, with a median age of about 18 years. The Spearman rho test was used to identify statistically significant covariance among selected physical properties and constituents in the ground water. The alkalinity, specific conductance, and dissolved solids increased as age increased; these correlations reflect common changes in ground-water quality that occur with increasing residence time and support the accuracy of the age estimates. The concentration of sodium and chloride increased as age increased; the correlation of these constituents is interpreted to indicate natural sources for chloride and sodium. The concentration of silica increased as the concentration of potassium increased; this correlation, in addition to the isotopic data, is evidence that

Correlation of geothermal springs with sub-surface fault terminations revealed by high-resolution, UAV-acquired magnetic data

USGS Publications Warehouse

Glen, Jonathan; A.E. Egger,; C. Ippolito,; N.Athens,

2013-01-01

There is widespread agreement that geothermal springs in extensional geothermal systems are concentrated at fault tips and in fault interaction zones where porosity and permeability are dynamically maintained (Curewitz and Karson, 1997; Faulds et al., 2010). Making these spatial correlations typically involves geological and geophysical studies in order to map structures and their relationship to springs at the surface. Geophysical studies include gravity and magnetic surveys, which are useful for identifying buried, intra-basin structures, especially in areas where highly magnetic, dense mafic volcanic rocks are interbedded with, and faulted against less magnetic, less dense sedimentary rock. High-resolution magnetic data can also be collected from the air in order to provide continuous coverage. Unmanned aerial systems (UAS) are well-suited for conducting these surveys as they can provide uniform, low-altitude, high-resolution coverage of an area without endangering crew. In addition, they are more easily adaptable to changes in flight plans as data are collected, and improve efficiency. We have developed and tested a new system to collect magnetic data using small-platform UAS. We deployed this new system in Surprise Valley, CA, in September, 2012, on NASA's SIERRA UAS to perform a reconnaissance survey of the entire valley as well as detailed surveys in key transition zones. This survey has enabled us to trace magnetic anomalies seen in ground-based profiles along their length. Most prominent of these is an intra-basin magnetic high that we interpret as a buried, faulted mafic dike that runs a significant length of the valley. Though this feature lacks surface expression, it appears to control the location of geothermal springs. All of the major hot springs on the east side of the valley lie along the edge of the high, and more specifically, at structural transitions where the high undergoes steps, bends, or breaks. The close relationship between the springs

75 FR 57976 - Designation of Service Area for Confederated Tribes of the Warm Springs of Oregon

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-23

... office hours at Hood River County. Dated: August 26, 2010. Larry Echo Hawk, Assistant Secretary--Indian... will expand the service area for the Warm Springs Tribe to include Hood River County (Oregon). The...

Holocene surface-faulting earthquakes at the Spring Lake and North Creek Sites on the Wasatch Fault Zone: Evidence for complex rupture of the Nephi Segment

USGS Publications Warehouse

Duross, Christopher; Hylland, Michael D.; Hiscock, Adam; Personius, Stephen; Briggs, Richard; Gold, Ryan D.; Beukelman, Gregg; McDonald, Geg N; Erickson, Ben; McKean, Adam; Angster, Steve; King, Roselyn; Crone, Anthony J.; Mahan, Shannon

2017-01-01

The Nephi segment of the Wasatch fault zone (WFZ) comprises two fault strands, the northern and southern strands, which have evidence of recurrent late Holocene surface-faulting earthquakes. We excavated paleoseismic trenches across these strands to refine and expand their Holocene earthquake chronologies; improve estimates of earthquake recurrence, displacement, and fault slip rate; and assess whether the strands rupture separately or synchronously in large earthquakes. Paleoseismic data from the Spring Lake site expand the Holocene record of earthquakes on the northern strand: at least five to seven earthquakes ruptured the Spring Lake site at 0.9 ± 0.2 ka (2σ), 2.9 ± 0.7 ka, 4.0 ± 0.5 ka, 4.8 ± 0.8 ka, 5.7 ± 0.8 ka, 6.6 ± 0.7 ka, and 13.1 ± 4.0 ka, yielding a Holocene mean recurrence of ~1.2–1.5 kyr and vertical slip rate of ~0.5–0.8 mm/yr. Paleoseismic data from the North Creek site help refine the Holocene earthquake chronology for the southern strand: at least five earthquakes ruptured the North Creek site at 0.2 ± 0.1 ka (2σ), 1.2 ± 0.1 ka, 2.6 ± 0.9 ka, 4.0 ± 0.1 ka, and 4.7 ± 0.7 ka, yielding a mean recurrence of 1.1–1.3 kyr and vertical slip rate of ~1.9–2.0 mm/yr. We compare these Spring Lake and North Creek data with previous paleoseismic data for the Nephi segment and report late Holocene mean recurrence intervals of ~1.0–1.2 kyr for the northern strand and ~1.1–1.3 kyr for the southern strand. The northern and southern strands have similar late Holocene earthquake histories, which allow for models of both independent and synchronous rupture. However, considering the earthquake timing probabilities and per-event vertical displacements, we have the greatest confidence in the simultaneous rupture of the strands, including rupture of one strand with spillover rupture to the other. Ultimately, our results improve the surface-faulting earthquake history of the Nephi segment and enhance our understanding of how structural barriers

Gas exchange and water relations responses of spring wheat to full-season infrared warming

USDA-ARS?s Scientific Manuscript database

Gas exchange and water relations responses to full-season in situ infrared (IR) warming were evaluated for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semi-arid desert region of the Southwest USA. A Temperature Free-Air Controlled Enhancement (T-FACE) ap...

Gas Exchange and Water Relations Responses of Spring Wheat to Full-Season Infrared Warming

USDA-ARS?s Scientific Manuscript database

Gas exchange and water relations were evaluated under full-season in situ infrared (IR) warming for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semiarid desert region of the southwest USA. A temperature free-air controlled enhancement (T-FACE) apparatus u...

Paleoearthquakes and Eolian-dominated fault sedimentation along the Hubbell Spring fault zone near Albuquerque, New Mexico

USGS Publications Warehouse

Personius, S.F.; Mahan, S.A.

2003-01-01

The Hubbell Spring fault zone forms the modern eastern margin of the Rio Grande rift in the Albuquerque basin of north-central New Mexico. Knowledge of its seismic potential is important because the fault zone transects Kirtland Air Force Base/Sandia National Laboratories and underlies the southern Albuquerque metropolitan area. No earthquakes larger than ML 5.5 have been reported in the last 150 years in this region, so we excavated the first trench across this fault zone to determine its late Quaternary paleoseismic history. Our trench excavations revealed a complex, 16-m-wide fault zone overlain by four tapered blankets of mixed eolian sand and minor colluvium that we infer were deposited after four large-magnitude, surface-rupturing earthquakes. Although the first (oldest) rupture event is undated, we used luminescence (thermoluminescence and infrared-stimulated luminescence) ages to determine that the subsequent three rupture events occurred about 56 ?? 6, 29 ?? 3, and 12 ?? 1 ka. These ages yield recurrence intervals of 27 and 17 k.y. between events and an elapsed time of 12 k.y. since the latest surface-rupturing paleoearthquake. Slip rates are not well constrained, but our preferred average slip rate since rupture event 2 (post-56 ka) is 0.05 mm/yr, and interval slip rates between the last three events are 0.06 and 0.09 mm/yr, respectively. Vertical displacements of 1-2 m per event and probable rupture lengths of 34-43 km indicate probable paleoearthquake magnitudes (Ms or Mw) of 6.8-7.1. Future earthquakes of this size likely would cause strong ground motions in the Albuquerque metropolitan area.

Integrated geophysical investigations of Main Barton Springs, Austin, Texas, USA

NASA Astrophysics Data System (ADS)

Saribudak, By Mustafa; Hauwert, Nico M.

2017-03-01

Barton Springs is a major discharge site for the Barton Springs Segment of the Edwards Aquifer and is located in Zilker Park, Austin, Texas. Barton Springs actually consists of at least four springs. The Main Barton Springs discharges into the Barton Springs pool from the Barton Springs fault and several outlets along a fault, from a cave, several fissures, and gravel-filled solution cavities on the floor of the pool west of the fault. Surface geophysical surveys [resistivity imaging, induced polarization (IP), self-potential (SP), seismic refraction, and ground penetrating radar (GPR)] were performed across the Barton Springs fault and at the vicinity of the Main Barton Springs in south Zilker Park. The purpose of the surveys was two-fold: 1) locate the precise location of submerged conduits (caves, voids) carrying flow to Main Barton Springs; and 2) characterize the geophysical signatures of the fault crossing Barton Springs pool. Geophysical results indicate significant anomalies to the south of the Barton Springs pool. A majority of these anomalies indicate a fault-like pattern, in front of the south entrance to the swimming pool. In addition, resistivity and SP results, in particular, suggest the presence of a large conduit in the southern part of Barton Springs pool. The groundwater flow-path to the Main Barton Springs could follow the locations of those resistivity and SP anomalies along the newly discovered fault, instead of along the Barton Springs fault, as previously thought.

Current spring warming as a driver of selection on reproductive timing in a wild passerine.

PubMed

Marrot, Pascal; Charmantier, Anne; Blondel, Jacques; Garant, Dany

2018-05-01

Evolutionary adaptation as a response to climate change is expected for fitness-related traits affected by climate and exhibiting genetic variance. Although the relationship between warmer spring temperature and earlier timing of reproduction is well documented, quantifications and predictions of the impact of global warming on natural selection acting on phenology in wild populations remain rare. If global warming affects fitness in a similar way across individuals within a population, or if fitness consequences are independent of phenotypic variation in key-adaptive traits, then no evolutionary response is expected for these traits. Here, we quantified the selection pressures acting on laying date during a 24-year monitoring of blue tits in southern Mediterranean France, a hot spot of climate warming. We explored the temporal fluctuation in annual selection gradients and we determined its temperature-related drivers. We first investigated the month-specific warming since 1970 in our study site and tested its influence on selection pressures, using a model averaging approach. Then, we quantified the selection strength associated with temperature anomalies experienced by the blue tit population. We found that natural selection acting on laying date significantly fluctuated both in magnitude and in sign across years. After identifying a significant warming in spring and summer, we showed that warmer daily maximum temperatures in April were significantly associated with stronger selection pressures for reproductive timing. Our results indicated an increase in the strength of selection by 46% for every +1°C anomaly. Our results confirm the general assumption that recent climate change translates into strong selection favouring earlier breeders in passerine birds. Our findings also suggest that differences in fitness among individuals varying in their breeding phenology increase with climate warming. Such climate-driven influence on the strength of directional

Quantifying Vertical Exhumation in Intracontinental Strike-Slip Faults: the Garlock fault zone, southern California

NASA Astrophysics Data System (ADS)

Chinn, L.; Blythe, A. E.; Fendick, A.

2012-12-01

New apatite fission-track ages show varying rates of vertical exhumation at the eastern terminus of the Garlock fault zone. The Garlock fault zone is a 260 km long east-northeast striking strike-slip fault with as much as 64 km of sinistral offset. The Garlock fault zone terminates in the east in the Avawatz Mountains, at the intersection with the dextral Southern Death Valley fault zone. Although motion along the Garlock fault west of the Avawatz Mountains is considered purely strike-slip, uplift and exhumation of bedrock in the Avawatz Mountains south of the Garlock fault, as recently as 5 Ma, indicates that transpression plays an important role at this location and is perhaps related to a restricting bend as the fault wraps around and terminates southeastward along the Avawatz Mountains. In this study we complement extant thermochronometric ages from within the Avawatz core with new low temperature fission-track ages from samples collected within the adjacent Garlock and Southern Death Valley fault zones. These thermochronometric data indicate that vertical exhumation rates vary within the fault zone. Two Miocene ages (10.2 (+5.0/-3.4) Ma, 9.0 (+2.2/-1.8) Ma) indicate at least ~3.3 km of vertical exhumation at ~0.35 mm/yr, assuming a 30°C/km geothermal gradient, along a 2 km transect parallel and adjacent to the Mule Spring fault. An older Eocene age (42.9 (+8.7/-7.3) Ma) indicates ~3.3 km of vertical exhumation at ~0.08 mm/yr. These results are consistent with published exhumation rates of 0.35 mm/yr between ~7 and ~4 Ma and 0.13 mm/yr between ~15 and ~9 Ma, as determined by apatite fission-track and U-Th/He thermochronometry in the hanging-wall of the Mule Spring fault. Similar exhumation rates on both sides of the Mule Spring fault support three separate models: 1) Thrusting is no longer active along the Mule Spring fault, 2) Faulting is dominantly strike-slip at the sample locations, or 3) Miocene-present uplift and exhumation is below detection levels

Ecosystem Warming Affects Vertical Distribution of Leaf Gas Exchange Properties and Water Relations of Spring Wheat

USDA-ARS?s Scientific Manuscript database

The vertical distribution of gas exchange and water relations responses to full-season in situ infrared (IR) warming were evaluated for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semiarid desert region of the Southwest USA. A Temperature Free-Air Contro...

Direct Contribution of the Stratosphere to Recent West Antarctic Warming in Austral Spring

NASA Astrophysics Data System (ADS)

Nicolas, J. P.; Bromwich, D. H.

2015-12-01

The causes of the rapid warming of West Antarctica in recent decades are not yet fully understood. Thus far, investigations of the phenomenon have emphasized the role of tropospheric teleconnections originating from the Tropics in austral winter, but have had less success in explaining the strong warming in austral spring (SON). Here, we further explore the mechanisms behind the SON warming by focusing on September, the month during which atmospheric temperature and circulation trends in and around West Antarctica largely account for the 3-month average SON trends. We show that the tropospheric trends toward lower pressures/heights (more cyclonic) over the South Pacific sector of the Southern Ocean previously reported extend vertically well into the stratosphere. In the lower troposphere, these circulation changes, by steering more warm air toward West Antarctica, have likely contributed to the warming of the region. In the stratosphere, we provide evidence that the cyclonic trends are associated with a very prominent stratospheric warming in the Australian sector, believed to be the result of increased tropically-forced planetary wave activity and wave breaking. Through thermal wind balance, this regional stratospheric warming has led to a poleward displacement of the polar-night jet south of Australia, leading to enhanced cyclonic motion and potential vorticity (PV) downwind over the Amundsen Sea region. Finally, we establish, through the PV inversion framework, a causal link between stratospheric and tropospheric changes, whereby large PV anomalies in the stratosphere induce consistent geopotential height anomalies down in the troposphere. Our results highlight not only the important and largely overlooked role played by the stratosphere in recent West Antarctic climate change, but also a new pathway for tropical climate variability to influence Antarctic climate.

Has climatic warming altered spring flowering date of Sonoran Desert shrubs?

USGS Publications Warehouse

Bowers, Janice E.

2007-01-01

With global warming, flowering at many locations has shifted toward earlier dates of bloom. A steady increase in average annual temperature since the late 1890s makes it likely that flowering also has advanced in the northern Sonoran Desert of the southwestern United States and northwestern Mexico. In this study, phenological models were used to predict annual date of spring bloom in the northern Sonoran Desert from 1894 to 2004; then, herbarium specimens were assessed for objective evidence of the predicted shift in flowering time. The phenological models were derived from known flowering requirements (triggers and heat sums) of Sonoran Desert shrubs. According to the models, flowering might have advanced by 20-41 d from 1894 to 2004. Analysis of herbarium specimens collected during the 20th century supported the model predictions. Over time, there was a significant increase in the proportion of shrub specimens collected in flower in March and a significant decrease in the proportion collected in May. Thus, the flowering curve - the proportion of individuals in flower in each spring month - shifted toward the start of the calendar year between 1900 and 1999. This shift could not be explained by collection activity: collectors showed no tendency to be active earlier in the year as time went on, nor did activity toward the end of spring decline in recent decades. Earlier bloom eventually could have substantial impacts on plant and animal communities in the Sonoran Desert, especially on migratory hummingbirds and population dynamics of shrubs.

Relative abundance and lengths of Kendall Warm Springs dace captured from different habitats in a specially designed trap

USGS Publications Warehouse

Gryska, A.D.; Hubert, W.A.; Gerow, K.G.

1998-01-01

A trap was designed to capture endangered Kendall Warm Springs dace Rhinichthys osculus thermalis (a subspecies of speckled dace Rhinichthys osculus) without being destructive to the habitat of the fish in Kendall Warm Springs Creek, Wyoming. Four experiments were conducted to determine differences in catch per unit effort (CPUE) and length frequencies of fish among differing habitat types. The CPUE was highest in channel habitats with current, and one experiment indicated that it was particularly high at vertical interfaces with vegetation. Longer fish were captured in channel habitats away from vegetation than in vegetated areas. The CPUE was significantly greater during the day than at night during one experiment, but no significant differences were observed among the other three experiments. The traps were easy and inexpensive to construct, could be used in a variety of stream habitats, and may have applications in other small streams for sampling small, benthic fishes.

Ground-water data for the Warm Springs Indian Reservation and contiguous areas north-central Oregon

USGS Publications Warehouse

Anderson, Donald B.

1996-01-01

This report presents well data that were collected and compiled during 1985-86 by the U.S. Geological Survey and used to determine the amount of ground water discharging to the Deschutes River on and near the Warm Springs Indian Reservation. The report contains well-construction data from 171 wells, information from drillers' logs for 66 wells, water-level data for 29 wells, and a map showing well locations.

Investigations into the Fish Lake Valley Fault Zone (FLVFZ) and its interactions with normal faulting within Eureka and Deep Springs Valleys

NASA Astrophysics Data System (ADS)

Lawson, M. J.; Rhodes, E.; Yin, A.

2016-12-01

In most textbooks, the San Andreas Fault is stated to be the plate boundary between the North American and the Pacific plates, as plate tectonics assumes that boundaries are essentially discrete. In the Western United States this is not the case, as up to 25% of relative plate motion is accommodated on other structures within the Walker Lane Shear Zone (WLSZ) in a diffuse 100 km margin (Faulds et al., 2005; Oldow et al., 2001). Fish Lake Valley Fault Zone (FLVFZ), situated at the northern border of Death Valley National Park, is the northern continuation of the Furnace Creek Fault Zone (FCFZ), and is an important transfer structure within the Walker Lane Shear Zone. Though the FLVFZ has a long term rate (since 10 Ma) of 5 mm/yr (Reheis and Sawyer, 1997), it has a highly variable slip rate. In the middle Pleistocene, the rate has a maximum of up to 11 mm/yr which would accommodate nearly the entirety of slip within the Walker Lane, and yet this rate decreases significantly ( 2.5 to 3 mm/yr) by the late Pleistocene due to unknown causes (Frankel et al. 2007). This variation in slip rate has been proposed by previous workers to be due to strain transience, an increase in the overall strain rate, or due to other unknown structures (Lee et al., 2009). Currently, we are investigating the cause of this variation, and the possibility of the transfer of slip to faults south of the FLVFZ on oblique normal faults within Eureka and Deep Springs Valleys. Preliminary data will be shown utilizing scarp transects, geomorphic scarp modeling, and Optically Stimulated Luminescence (OSL) dating techniques.

Predicting the patterns of change in spring onset and false springs in China during the twenty-first century

NASA Astrophysics Data System (ADS)

Zhu, Likai; Meng, Jijun; Li, Feng; You, Nanshan

2017-10-01

Spring onset has generally shifted earlier in China over the past several decades in response to the warming climate. However, future changes in spring onset and false springs, which will have profound effects on ecosystems, are still not well understood. Here, we used the extended form of the Spring Indices model (SI-x) to project changes in the first leaf and first bloom dates, and predicted false springs for the historical (1950-2005) and future (2006-2100) periods based on the downscaled daily maximum/minimum temperatures under two emission scenarios from 21 General Circulation Models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5). On average, first leaf and first bloom in China were projected to occur 21 and 23 days earlier, respectively, by the end of the twenty-first century in the Representative Concentration Pathway (RCP) 8.5 scenario. Areas with greater earlier shifts in spring onset were in the warm temperate zone, as well as the north and middle subtropical zones of China. Early false spring risk increased rapidly in the warm temperate and north subtropical zones, while that declined in the cold temperate zone. Relative to early false spring risk, late false spring risk showed a common increase with smaller magnitude in the RCP 8.5 scenario but might cause greater damage to ecosystems because plants tend to become more vulnerable to the later occurrence of a freeze event. We conclude that future climate warming will continue to cause earlier occurrence of spring onset in general, but might counterintuitively increase plant damage risk in natural and agricultural systems of the warm temperate and subtropical China.

Predicting the patterns of change in spring onset and false springs in China during the twenty-first century.

PubMed

Zhu, Likai; Meng, Jijun; Li, Feng; You, Nanshan

2017-10-28

Spring onset has generally shifted earlier in China over the past several decades in response to the warming climate. However, future changes in spring onset and false springs, which will have profound effects on ecosystems, are still not well understood. Here, we used the extended form of the Spring Indices model (SI-x) to project changes in the first leaf and first bloom dates, and predicted false springs for the historical (1950-2005) and future (2006-2100) periods based on the downscaled daily maximum/minimum temperatures under two emission scenarios from 21 General Circulation Models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5). On average, first leaf and first bloom in China were projected to occur 21 and 23 days earlier, respectively, by the end of the twenty-first century in the Representative Concentration Pathway (RCP) 8.5 scenario. Areas with greater earlier shifts in spring onset were in the warm temperate zone, as well as the north and middle subtropical zones of China. Early false spring risk increased rapidly in the warm temperate and north subtropical zones, while that declined in the cold temperate zone. Relative to early false spring risk, late false spring risk showed a common increase with smaller magnitude in the RCP 8.5 scenario but might cause greater damage to ecosystems because plants tend to become more vulnerable to the later occurrence of a freeze event. We conclude that future climate warming will continue to cause earlier occurrence of spring onset in general, but might counterintuitively increase plant damage risk in natural and agricultural systems of the warm temperate and subtropical China.

The influence of local spring temperature variance on temperature sensitivity of spring phenology.

PubMed

Wang, Tao; Ottlé, Catherine; Peng, Shushi; Janssens, Ivan A; Lin, Xin; Poulter, Benjamin; Yue, Chao; Ciais, Philippe

2014-05-01

The impact of climate warming on the advancement of plant spring phenology has been heavily investigated over the last decade and there exists great variability among plants in their phenological sensitivity to temperature. However, few studies have explicitly linked phenological sensitivity to local climate variance. Here, we set out to test the hypothesis that the strength of phenological sensitivity declines with increased local spring temperature variance, by synthesizing results across ground observations. We assemble ground-based long-term (20-50 years) spring phenology database (PEP725 database) and the corresponding climate dataset. We find a prevalent decline in the strength of phenological sensitivity with increasing local spring temperature variance at the species level from ground observations. It suggests that plants might be less likely to track climatic warming at locations with larger local spring temperature variance. This might be related to the possibility that the frost risk could be higher in a larger local spring temperature variance and plants adapt to avoid this risk by relying more on other cues (e.g., high chill requirements, photoperiod) for spring phenology, thus suppressing phenological responses to spring warming. This study illuminates that local spring temperature variance is an understudied source in the study of phenological sensitivity and highlight the necessity of incorporating this factor to improve the predictability of plant responses to anthropogenic climate change in future studies. © 2013 John Wiley & Sons Ltd.

Effects of groundwater withdrawals from the Hurricane Fault zone on discharge of saline water from Pah Tempe Springs, Washington County, Utah

USGS Publications Warehouse

Gardner, Philip M.

2018-04-10

Pah Tempe Springs, located in Washington County, Utah, contribute about 95,000 tons of dissolved solids annually along a 1,500-foot gaining reach of the Virgin River. The river gains more than 10 cubic feet per second along the reach as thermal, saline springwater discharges from dozens of orifices located along the riverbed and above the river on both banks. The spring complex discharges from fractured Permian Toroweap Limestone where the river crosses the north-south trending Hurricane Fault. The Bureau of Reclamation Colorado River Basin Salinity Control Program is evaluating the feasibility of capturing and desalinizing the discharge of Pah Tempe Springs to improve downstream water quality in the Virgin River. The most viable plan, identified by the Bureau of Reclamation in early studies, is to capture spring discharge by pumping thermal groundwater from within the Hurricane Fault footwall damage zone and to treat this water prior to returning it to the river.Three multiple-day interference tests were conducted between November 2013 and November 2014, wherein thermal groundwater was pumped from fractured carbonate rock in the fault damage zone at rates of up to 7 cubic feet per second. Pumping periods for these tests lasted approximately 66, 74, and 67 hours, respectively, and the tests occurred with controlled streamflows of approximately 2.0, 3.5, and 24.5 cubic feet per second, respectively, in the Virgin River upstream from the springs reach. Specific conductance, water temperature, and discharge were monitored continuously in the river (upstream and downstream of the springs reach) at selected individual springs, and in the pumping discharge during each of the tests. Water levels were monitored in three observation wells screened in the thermal system. Periodic stream and groundwater samples were analyzed for dissolved-solids concentration and the stable isotopes of oxygen and hydrogen. Additional discrete measurements of field parameters (specific

3D Model of the Neal Hot Springs Geothermal Area

DOE Data Explorer

Faulds, James E.

2013-12-31

The Neal Hot Springs geothermal system lies in a left-step in a north-striking, west-dipping normal fault system, consisting of the Neal Fault to the south and the Sugarloaf Butte Fault to the north (Edwards, 2013). The Neal Hot Springs 3D geologic model consists of 104 faults and 13 stratigraphic units. The stratigraphy is sub-horizontal to dipping <10 degrees and there is no predominant dip-direction. Geothermal production is exclusively from the Neal Fault south of, and within the step-over, while geothermal injection is into both the Neal Fault to the south of the step-over and faults within the step-over.

Methanotrophic bacteria in warm geothermal spring sediments identified using stable-isotope probing.

PubMed

Sharp, Christine E; Martínez-Lorenzo, Azucena; Brady, Allyson L; Grasby, Stephen E; Dunfield, Peter F

2014-10-01

We investigated methanotrophic bacteria in sediments of several warm geothermal springs ranging in temperature from 22 to 45 °C. Methane oxidation was measured at potential rates up to 141 μmol CH4 d(-1) g(-1) sediment. Active methanotrophs were identified using (13) CH4 stable-isotope probing (SIP) incubations performed at close to in situ temperatures for each site. Quantitative (q) PCR of pmoA genes identified the position of the heavy ((13) C-labelled) DNA fractions in density gradients, and 16S rRNA gene pyrotag sequencing of the heavy fractions was performed to identify the active methanotrophs. Methanotroph communities identified in heavy fractions of all samples were predominated by species similar (≥ 95% 16S rRNA gene identities) to previously characterized Gammaproteobacteria and Alphaproteobacteria methanotrophs. Among the five hottest samples (45 °C), members of the Gammaproteobacteria genus Methylocaldum dominated in two cases, while three others were dominated by an OTU closely related (96.8% similarity) to the Alphaproteobacteria genus Methylocapsa. These results suggest that diverse methanotroph groups are adapted to warm environments, including the Methylocapsa-Methylocella-Methyloferula group, which has previously only been detected in cooler sites. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Failure analysis of energy storage spring in automobile composite brake chamber

NASA Astrophysics Data System (ADS)

Luo, Zai; Wei, Qing; Hu, Xiaofeng

2015-02-01

This paper set energy storage spring of parking brake cavity, part of automobile composite brake chamber, as the research object. And constructed the fault tree model of energy storage spring which caused parking brake failure based on the fault tree analysis method. Next, the parking brake failure model of energy storage spring was established by analyzing the working principle of composite brake chamber. Finally, the data of working load and the push rod stroke measured by comprehensive test-bed valve was used to validate the failure model above. The experimental result shows that the failure model can distinguish whether the energy storage spring is faulted.

Extreme warm temperatures alter forest phenology and productivity in Europe.

PubMed

Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

2016-09-01

Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. Copyright © 2016 Elsevier B.V. All rights reserved.

Major thermal springs of Utah

USGS Publications Warehouse

Mundorff, J.C.

1970-01-01

As part of a study of the springs of Utah, reconnaissance data were obtained on the thermal, chemical, and geologic characteristics of the major thermal springs or Utah. Only three of the springs have temperatures near the boiling point of water; the maximum recorded temperatures of these springs range from 185° to 189° F. All three springs are in or near areas of late Tertiary or Quaternary volcanism.Temperatures of the thermal springs studied ranged from 68° to 189° F. Nearly all thermal springs in Utah are in or near fault zones. Very few of these springs issue from volcanic rocks, but several springs are close to areas of late Tertiary or Quaternary volcanic rocks.

One-dimensional modeling of thermal energy produced in a seismic fault

NASA Astrophysics Data System (ADS)

Konga, Guy Pascal; Koumetio, Fidèle; Yemele, David; Olivier Djiogang, Francis

2017-12-01

Generally, one observes an anomaly of temperature before a big earthquake. In this paper, we established the expression of thermal energy produced by friction forces between the walls of a seismic fault while considering the dynamic of a one-dimensional spring-block model. It is noted that, before the rupture of a seismic fault, displacements are caused by microseisms. The curves of variation of this thermal energy with time show that, for oscillatory and aperiodic displacement, the thermal energy is accumulated in the same way. The study reveals that thermal energy as well as temperature increases abruptly after a certain amount of time. We suggest that the corresponding time is the start of the anomaly of temperature observed which can be considered as precursory effect of a big seism. We suggest that the thermal energy can heat gases and dilate rocks until they crack. The warm gases can then pass through the cracks towards the surface. The cracks created by thermal energy can also contribute to the rupture of the seismic fault. We also suggest that the theoretical model of thermal energy, produced in seismic fault, associated with a large quantity of experimental data may help in the prediction of earthquakes.

Soda Creek springs - metamorphic waters in the eastern Alaska Range

USGS Publications Warehouse

Richter, D.H.; Donaldson, D.E.; Lamarre, R.A.

1973-01-01

The Soda Creek springs are a group of small, cold mineral springs on the southern flank of the eastern Alaska Range. The spring waters contain anomalous concentrations of carbon dioxide, sodium, chlorine, sulfate, boron, and ammonia and are actively precipitating deposits of calcite and aragonite. Sparingly present in these deposits are mixed-layer illite-montmorillonite clays and zeolite minerals. Low-temperaturemetamorphic reactions in subjacent marine sedimentary rocks of Jurassic and Cretaceous age may have produced the fluids and silicate minerals. With only a few exceptions, cool bicarbonate-rich springs in Alaska are concentrated south of the Denali fault system in south-central Alaska, southeastern Alaska, and along the Kaltag-Tintina fault system. These areas are characterized by active or recently activetectonism, major faults and folds, and an abundance of marine sedimentary rocks.

A reversal of the shift towards earlier spring phenology in several Mediterranean reptiles and amphibians during the 1998-2013 warming slowdown.

PubMed

Prodon, Roger; Geniez, Philippe; Cheylan, Marc; Devers, Florence; Chuine, Isabelle; Besnard, Aurelien

2017-12-01

Herps, especially amphibians, are particularly susceptible to climate change, as temperature tightly controls many parameters of their biological cycle-above all, their phenology. The timing of herps' activity or migration period-in particular the dates of their first appearance in spring and first breeding-and the shift to earlier dates in response to warming since the last quarter of the 20 th century has often been described up to now as a nearly monotonic trend towards earlier phenological events. In this study, we used citizen science data opportunistically collected on reptiles and amphibians in the northern Mediterranean basin over a period of 32 years to explore temporal variations in herp phenology. For 17 common species, we measured shifts in the date of the species' first spring appearance-which may be the result of current changes in climate-and regressed the first appearance date against temperatures and precipitations. Our results confirmed the expected overall trend towards earlier first spring appearances from 1983 to 1997, and show that the first appearance date of both reptiles and amphibians fits well with the temperature in late winter. However, the trend towards earlier dates was stopped or even reversed in most species between 1998 and 2013. We interpret this reversal as a response to cooling related to the North Atlantic Oscillation (NAO) in the late winter and early spring. During the positive NAO episodes, for certain species only (mainly amphibians), the effect of a warm weather, which tends to advance the phenology, seems to be counterbalanced by the adverse effects of the relative dryness. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

A signal-based fault detection and classification method for heavy haul wagons

NASA Astrophysics Data System (ADS)

Li, Chunsheng; Luo, Shihui; Cole, Colin; Spiryagin, Maksym; Sun, Yanquan

2017-12-01

This paper proposes a signal-based fault detection and isolation (FDI) system for heavy haul wagons considering the special requirements of low cost and robustness. The sensor network of the proposed system consists of just two accelerometers mounted on the front left and rear right of the carbody. Seven fault indicators (FIs) are proposed based on the cross-correlation analyses of the sensor-collected acceleration signals. Bolster spring fault conditions are focused on in this paper, including two different levels (small faults and moderate faults) and two locations (faults in the left and right bolster springs of the first bogie). A fully detailed dynamic model of a typical 40t axle load heavy haul wagon is developed to evaluate the deterioration of dynamic behaviour under proposed fault conditions and demonstrate the detectability of the proposed FDI method. Even though the fault conditions considered in this paper did not deteriorate the wagon dynamic behaviour dramatically, the proposed FIs show great sensitivity to the bolster spring faults. The most effective and efficient FIs are chosen for fault detection and classification. Analysis results indicate that it is possible to detect changes in bolster stiffness of ±25% and identify the fault location.

Special Office Report for Warm Springs Dam and Lake Sonoma. Sonoma County, California. Section 7. Consultation on Endangered Species.

DTIC Science & Technology

1983-05-01

REPORT, SECTION 7 CONSULTATION, FN WARM SPRINGS DAM AND LAKE SONOMA, SONOMA COUNTY , F P IN CALIFORNIA 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(s) 8...regarding the American Peregrine Falcon (Falco peregrInus anatum) and its critical habitat (about 13,300 acres in Sonoma County , California) in the 29 May...federally owned historic resources. Actions to be undertaken will not impair historic properties. e. Sonoma County General Plan. This County Plan is a

Spring-fen habitat islands in a warming climate: Partitioning the effects of mesoclimate air and water temperature on aquatic and terrestrial biota.

PubMed

Horsák, Michal; Polášková, Vendula; Zhai, Marie; Bojková, Jindřiška; Syrovátka, Vít; Šorfová, Vanda; Schenková, Jana; Polášek, Marek; Peterka, Tomáš; Hájek, Michal

2018-09-01

Climate warming and associated environmental changes lead to compositional shifts and local extinctions in various ecosystems. Species closely associated with rare island-like habitats such as groundwater-dependent spring fens can be severely threatened by these changes due to a limited possibility to disperse. It is, however, largely unknown to what extent mesoclimate affects species composition in spring fens, where microclimate is buffered by groundwater supply. We assembled an original landscape-scale dataset on species composition of the most waterlogged parts of isolated temperate spring fens in the Western Carpathian Mountains along with continuously measured water temperature and hydrological, hydrochemical, and climatic conditions. We explored a set of hypotheses about the effects of mesoclimate air and local spring-water temperature on compositional variation of aquatic (macroinvertebrates), semi-terrestrial (plants) and terrestrial (land snails) components of spring-fen biota, categorized as habitat specialists and other species (i.e. matrix-derived). Water temperature did not show a high level of correlation with mesoclimate. For all components, fractions of compositional variation constrained to temperature were statistically significant and higher for habitat specialists than for other species. The importance of air temperature at the expense of water temperature and its fluctuation clearly increased with terrestriality, i.e. from aquatic macroinvertebrates via vegetation (bryophytes and vascular plants) to land snails, with January air temperature being the most important factor for land snails and plant specialists. Some calcareous-fen specialists with a clear distribution centre in temperate Europe showed a strong affinity to climatically cold sites in our study area and may hence be considered as threatened by climate warming. We conclude that prediction models solely based on air temperature may provide biased estimates of future changes in

Geophysical investigations of the geologic and hydrothermal framework of the Pilgrim Springs Geothermal Area, Alaska

USGS Publications Warehouse

Glen, Jonathan; McPhee, Darcy K.; Bedrosian, Paul A.

2014-01-01

Pilgrim Hot Springs, located on the Seward Peninsula in west-central Alaska, is characterized by hot springs, surrounding thawed regions, and elevated lake temperatures. The area is of interest because of its potential for providing renewable energy for Nome and nearby rural communities. We performed ground and airborne geophysical investigations of the Pilgrim Springs geothermal area to identify areas indicative of high heat flow and saline geothermal fluids, and to map key structures controlling hydrothermal fluid flow. Studies included ground gravity and magnetic measurements, as well as an airborne magnetic and frequency-domain electromagnetic (EM) survey. The structural and conceptual framework developed from this study provides critical information for future development of this resource and is relevant more generally to our understanding of geothermal systems in active extensional basins. Potential field data reveal the Pilgrim area displays a complex geophysical fabric reflecting a network of intersecting fault and fracture sets ranging from inherited basement structures to Tertiary faults. Resistivity models derived from the airborne EM data reveal resistivity anomalies in the upper 100 m of the subsurface that suggest elevated temperatures and the presence of saline fluids. A northwest trending fabric across the northeastern portion of the survey area parallels structures to the east that may be related to accommodation between the two major mountain ranges south (Kigluaik) and east (Bendeleben) of Pilgrim Springs. The area from the springs southward to the range front, however, is characterized by east-west trending, range-front-parallel anomalies likely caused by late Cenozoic structures associated with north-south extension that formed the basin. The area around the springs (~10 km2 ) is coincident with a circular magnetic high punctuated by several east-west trending magnetic lows, the most prominent occurring directly over the springs. These features

Assessing Whether Northeastern Earthquakes and Warm Springs Are Produced by the Northern Appalachian Anomaly

NASA Astrophysics Data System (ADS)

Marrero, A. M.; Abbott, D. H.; Menke, W. H.

2017-12-01

The passive margin of eastern North America has been tectonically quiescent for >100 Ma. However, earthquakes, mantle-derived 3He in ground water and warm springs hint at continued activity. The recent proposal of asthenospheric upwelling (the Northern Appalachian Anomaly, NAA) beneath southern New England (SNE) raises the possibility that this activity is due to mantle melt. Its delivery to the lithosphere may lower density and cause stress, open pathways for 3He, and heat the crust. We examine isostatic balance along the Levin et al. [2017] receiver function profile for which crustal thickness H and compressional-to-shear velocity ratio R are published. It crosses the continental margin north of the NAA and acts as a control against which regions closer to it may be compared. We use Christensen's [1996] measurements of rocks to predict crustal density Dc from R. Isostatic balance is estimated by combining H, Dc, elevation and mantle density Dm. We assume a constant Dm, which allows us to assess the imbalance due to factors other than mantle heterogeneities. The crust along the profile is not in isostatic balance, with very large disequilibrium pressure P (up to -33.6 MPa). We use the horizontal gradient of P as a proxy for crustal shear force and compare it to seismicity. The signals show significant correlation, indicating that both the isostatic imbalance and the crustal seismicity may be due to crustal features that are thought to be mostly "fossil'; that is, originating hundreds of millions of year ago when the crust was formed. While our results do not preclude the possibility that the present-day NAA is influencing isostatic disequilibria and seismicity in SNE, they indicate that distinguishing its effect from the very large ancient causes may be problematical. We also study warm springs underlain by the NAA and show that their temperatures have been stable over the last 100 years, suggesting their importance in long-term heat transport.

Linking atmospheric blocking to European temperature extremes in spring

NASA Astrophysics Data System (ADS)

Brunner, Lukas; Hegerl, Gabriele; Steiner, Andrea

2017-04-01

The weather in Europe is influenced by a range of dynamical features such as the Atlantic storm tracks, the jet stream, and atmospheric blocking. Blocking describes an atmospheric situation in which a stationary and persistent high pressure system interrupts the climatological flow for several days to weeks. It can trigger cold and warm spells which is of special relevance during the spring season because vegetation is particularly vulnerable to extreme temperatures in the early greening phase. We investigate European cold and warm spells in the 36 springs from 1979 to 2014 in temperature data from the European daily high-resolution gridded dataset (E-OBS) and connect them to blocking derived from geopotential height fields from ERA-Interim. A highly significant link between blocking and both, cold and warm spells is found that changes during spring. Resolving monthly frequencies, we find a shift in the preferred locations of blocking throughout spring. The maximum blocking frequency during cold spells shifts from Scandinavia to the British Isles in March and April. During warm spells it continuously shifts further northward during the spring season. The location of the block is found to be essential for the sign of the relationship. Blocking over the north-eastern Atlantic and over northern Europe is strongly linked to cold conditions, while blocking over central Europe is associated with warm conditions. Consistently the spatial distribution of temperature extremes across Europe is highly sensitive to the occurrence of blocking. More than 80 % of cold spells in south-eastern Europe occur during blocking, compared to less than 30 % in northern Europe. Warm spells show the opposite pattern and more than 70 % co-occur with blocking in northern Europe, compared to less than 30 % in parts of southern Europe. We find considerable interannual variability over the analysis period from 1979 to 2014 but also a decrease in cold spells and an increase in warm spells

Geologic framework of thermal springs, Black Canyon, Nevada and Arizona

USGS Publications Warehouse

Beard, L. Sue; Anderson, Zachary W.; Felger, Tracey J.; Seixas, Gustav B.

2014-01-01

Thermal springs in Black Canyon of the Colorado River, downstream of Hoover Dam, are important recreational, ecological, and scenic features of the Lake Mead National Recreation Area. This report presents the results from a U.S. Geological Survey study of the geologic framework of the springs. The study was conducted in cooperation with the National Park Service and funded by both the National Park Service and National Cooperative Geologic Mapping Program of the U.S. Geological Survey. The report has two parts: A, a 1:48,000-scale geologic map created from existing geologic maps and augmented by new geologic mapping and geochronology; and B, an interpretive report that presents results based on a collection of fault kinematic data near springs within Black Canyon and construction of 1:100,000-scale geologic cross sections that extend across the western Lake Mead region. Exposures in Black Canyon are mostly of Miocene volcanic rocks, underlain by crystalline basement composed of Miocene plutonic rocks or Proterozoic metamorphic rocks. The rocks are variably tilted and highly faulted. Faults strike northwest to northeast and include normal and strike-slip faults. Spring discharge occurs along faults intruded by dacite dikes and plugs; weeping walls and seeps extend away from the faults in highly fractured rock or relatively porous volcanic breccias, or both. Results of kinematic analysis of fault data collected along tributaries to the Colorado River indicate two episodes of deformation, consistent with earlier studies. The earlier episode formed during east-northeast-directed extension, and the later during east-southeast-directed extension. At the northern end of the study area, pre-existing fault blocks that formed during the first episode were rotated counterclockwise along the left-lateral Lake Mead Fault System. The resulting fault pattern forms a complex arrangement that provides both barriers and pathways for groundwater movement within and around Black

Fault detection and diagnosis of diesel engine valve trains

NASA Astrophysics Data System (ADS)

Flett, Justin; Bone, Gary M.

2016-05-01

This paper presents the development of a fault detection and diagnosis (FDD) system for use with a diesel internal combustion engine (ICE) valve train. A novel feature is generated for each of the valve closing and combustion impacts. Deformed valve spring faults and abnormal valve clearance faults were seeded on a diesel engine instrumented with one accelerometer. Five classification methods were implemented experimentally and compared. The FDD system using the Naïve-Bayes classification method produced the best overall performance, with a lowest detection accuracy (DA) of 99.95% and a lowest classification accuracy (CA) of 99.95% for the spring faults occurring on individual valves. The lowest DA and CA values for multiple faults occurring simultaneously were 99.95% and 92.45%, respectively. The DA and CA results demonstrate the accuracy of our FDD system for diesel ICE valve train fault scenarios not previously addressed in the literature.

Microbial Diversity and Lipid Abundance in Microbial Mats from a Sulfidic, Saline, Warm Spring in Utah, USA

NASA Astrophysics Data System (ADS)

Gong, J.; Edwardson, C.; Mackey, T. J.; Dzaugis, M.; Ibarra, Y.; Course 2012, G.; Frantz, C. M.; Osburn, M. R.; Hirst, M.; Williamson, C.; Hanselmann, K.; Caporaso, J.; Sessions, A. L.; Spear, J. R.

2012-12-01

The microbial diversity of Stinking Springs, a sulfidic, saline, warm spring northeast of the Great Salt Lake was investigated. The measured pH, temperature, salinity, and sulfide concentration along the flow path ranged from 6.64-7.77, 40-28° C, 2.9-2.2%, and 250 μM to negligible, respectively. Five sites were selected along the flow path and within each site microbial mats were dissected into depth profiles based on the color and texture of the mat layers. Genomic DNA was extracted from each layer, and the 16S rRNA gene was amplified and sequenced on the Roche 454 Titanium platform. Fatty acids were also extracted from the mat layers and analyzed by liquid chromatography and mass spectrometry. The mats at Stinking Springs were classified into roughly two morphologies with respect to their spatial distribution: loose, sometimes floating mats proximal to the spring source; and thicker, well-laminated mats distal to the spring source. Loosely-laminated mats were found in turbulent stream flow environments, whereas well-laminated mats were common in less turbulent sheet flows. Phototrophs, sulfur oxidizers, sulfate reducers, methanogens, other bacteria and archaea were identified by 16S rRNA gene sequences. Diatoms, identified by microscopy and lipid analysis were found to increase in abundance with distance from the source. Methanogens were generally more abundant in deeper mat laminae. Photoheterotrophs were found in all mat layers. Microbial diversity increased significantly with depth at most sites. In addition, two distinct microbial streamers were identified and characterized at the two fast flowing sites. These two streamer varieties were dominated by either cyanobacteria or flavobacteria. Overall, our genomic and lipid analysis suggest that the physical and chemical environment is more predictive of the community composition than mat morphology. Site Map

The south San Fernando Valley fault, Los Angeles California: Myth or reality

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

Slosson, J.E.; Phipps, M.B.; Werner, S.L.

1993-04-01

Based on related geomorphic and hydrogeologic evidence, the authors have identified the probable existence of a fault system and related Riedel faults along the southerly side of the San Fernando Valley (SFV), Los Angeles, CA. This fault system, which appears to be aligned along a series of pressure ridges, artesian springs and warm water wells, is termed the South SFV Fault for the purpose of this study. The trace of this fault is believed to roughly follow the southern extent of the SFV near the northern base of the east-west trending Santa Monica Mountains. The SFV is a fault-affected synclinalmore » structure bounded on the north, east, and west by well-recognized and documented fault systems. The southern boundary of the SFV is defined by the complexly faulted anticlinal structure of the bordering Santa Monica Mountains. This presentation will suggest that the southern boundary of the SFV (syncline) is controlled by faulting similar to the fault-controlled north, east, and west boundaries. The authors believe that the trace of the fault system in the southeastern portion of the SFV has been somewhat modified and concealed by the erosion and deposition of coarse grained sediments derived from the vast granitic-metamorphic complex of the San Gabriel Mountains to the north, the major watershed, and in part by sediment derived from similar rock type to the east and southeast. The western half of the SFV has been largely filled with fine grained sediments derived from erosion of the surrounding sedimentary uplands. Further modification has occurred due to urbanization of the area. With reference to the fault-affected boundaries on the west, north, and east sides of the SFV, these structures are all considered youthfall and capable of producing earthquakes as the SFF did in 1971. The south-bounding fault may fall within a similar category. Accordingly, the authors believe that the proposed South SFV Fault has been a tectonic feature since the Pliocene epoch.« less

Low-temperature geothermal potential of the Ojo Caliente warm springs area, northern New Mexico

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

Vuataz, F.D.; Stix, J.; Goff, F.

1984-05-01

A detailed geochemical investigation of 17 waters (thermal and cold, mineralized and dilute) was performed in the Ojo Caliente-La Madera area. Two types of thermomineral waters have separate and distinctive geologic, geochemical, and geothermal characteristics. The water from Ojo Caliente Resort emerges with temperatures less than or equal to 54/sup 0/C from a Precambrian metarhyolite. Its chemistry, typically Na-HCO/sub 3/, has a total mineralization of 3600 mg/l. Isotopic studies have shown that the thermal water emerges from the springs and a hot well without significant mixing with the cold shallow aquifer of the valley alluvium. However, the cold aquifer adjacentmore » to the resort does contain varying amounts of thermal water that originates from the warm spring system. Geothermometry calculations indicate that the thermal water may be as hot as 85/sup 0/C at depth before its ascent toward surface. Thermodynamic computations on the reaction states of numerous mineral phases suggest that the thermal water will not cause major scaling problems if the hot water is utilized for direct-use geothermal applications. By means of a network of very shallow holes, temperature and electrical conductivity anomalies have been found elsewhere in the valley around Ojo Caliente, and resistivity soundings have confirmed the presence of a plume of thermal water entering the shallow aquifer. The group of lukewarm springs around La Madera, with temperatures less than or equal to 29/sup 0/C, chemical type of NaCaMg-HCO/sub 3/Cl and with a total mineralization less than or equal to 1500 mg/l behaves as a different system without any apparent relation to the Ojo Caliente system. Its temperature at depth is not believed to exceed 35 to 40/sup 0/C.« less

Root and Shoot Phenology May Respond Differently to Warming

NASA Astrophysics Data System (ADS)

Radville, L.; Eissenstat, D. M.; Post, E.

2015-12-01

Climate change is increasing temperatures and extending the growing season for many organisms. Shifts in phenology have been widely reported in response to global warming and have strong effects on ecosystem processes and greenhouse gas emissions. It is well understood that warming generally advances aboveground plant phenology, but the influence of temperature on root phenology is unclear. Most terrestrial biosphere models assume that root and shoot growth occur at the same time and are influenced by warming in the same way, but recent studies suggest that this may not be the case. Testing this assumption is particularly important in the Arctic where over 70% of plant biomass can be belowground and warming is happening faster than in other ecosystems. In 2013 and 2014 we examined the timing of root growth in the Arctic in plots that had been warmed or unwarmed for 10 years. We found that peak root growth occurred about one month before leaf growth, suggesting that spring root phenology is not controlled by carbon produced during spring photosynthesis. If root phenology is not controlled by photosynthate early in the season, earlier spring leaf growth may not cause earlier spring root growth. In support of this, we found that warming advanced spring leaf cover but did not significantly affect root phenology. Root growth was not significantly correlated with soil temperature and did not appear to be limited by near-freezing temperatures above the permafrost. These results suggest that although shoots are influenced by temperature, roots in this system may be more influenced by photosynthesis and carbon storage. Aboveground phenology, one of the most widely measured aspects of climate change, may not represent whole-plant phenology and may be a poor indicator of the timing of whole-plant carbon fluxes. Additionally, climate model assumptions that roots and shoots grow at the same time may need to be revised.

Geologic reconnaissance of the Hot Springs Mountains, Churchill County, Nevada

USGS Publications Warehouse

Voegtly, Nickolas E.

1981-01-01

A geologic reconnaissance of the Hot Springs Mountains and adjacent areas, which include parts of the Brady-Hazen and the Stillwater-Soda Lake Known Geothermal Resource Areas, during June-December 1975, resulted in a reinterpretation of the nature and location of some Basin and Range faults. In addition, the late Cenozoic stratigraphy has been modified, chiefly on the basis of radiometric dates of volcanic rocks by U.S. Geological Survey personnel and others. The Hot Springs Mountains are in the western part of the Basin and Range province, which is characterized by east-west crustal extension and associated normal faulting. In the surrounding Trinity, West Humboldt, Stillwater, and Desert Mountains, Cenozoic rocks overlie ' basement ' rocks of the Paleozoic and Mesozoic age. A similar relation is inferred in the Hot Springs Mountains. Folding and faulting have taken place from the late Tertiary to the present. (USGS)

Final Scientific/Technical Report – DE-EE0002960 Recovery Act. Detachment faulting and Geothermal Resources - An Innovative Integrated Geological and Geophysical Investigation of Pearl Hot Spring, Nevada

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

Stockli, Daniel F.

2015-11-30

The Pearl Host Spring Geothermal Project funded by the DoE Geothermal Program was a joint academic (KU/UT & OU) and industry collaboration (Sierra and Ram Power) to investigate structural controls and the importance of low-angle normal faults on geothermal fluid flow through a multifaceted geological, geophysical, and geochemical investigation in west-central Nevada. The study clearly showed that the geothermal resources in Clayton Valley are controlled by the interplay between low-angle normal faults and active deformation related to the Walker Lane. The study not only identified potentially feasible blind geothermal resource plays in eastern Clayton Valley, but also provide a transportablemore » template for exploration in the area of west-central Nevada and other regional and actively-deforming releasing fault bends. The study showed that deep-seated low-angle normal faults likely act as crustal scale permeability boundaries and could play an important role in geothermal circulation and funneling geothermal fluid into active fault zones. Not unique to this study, active deformation is viewed as an important gradient to rejuvenated fracture permeability aiding the long-term viability of blind geothermal resources. The technical approach for Phase I included the following components, (1) Structural and geological analysis of Pearl Hot Spring Resource, (2) (U-Th)/He thermochronometry and geothermometry, (3) detailed gravity data and modeling (plus some magnetic and resistivity), (4) Reflection and Refraction Seismic (Active Source), (5) Integration with existing and new geological/geophysical data, and (6) 3-D Earth Model, combining all data in an innovative approach combining classic work with new geochemical and geophysical methodology to detect blind geothermal resources in a cost-effective fashion.« less

Race and the politics of polio: Warm Springs, Tuskegee, and the March of Dimes.

PubMed

Rogers, Naomi

2007-05-01

The Tuskegee Institute opened a polio center in 1941, funded by the March of Dimes. The center's founding was the result of a new visibility of Black polio survivors and the growing political embarrassment around the policy of the Georgia Warm Springs polio rehabilitation center, which Franklin Roosevelt had founded in the 1920s before he became president and which had maintained a Whites-only policy of admission. This policy, reflecting the ubiquitous norm of race-segregated health facilities of the era, was also sustained by a persuasive scientific argument about polio itself: that Blacks were not susceptible to the disease. After a decade of civil rights activism, this notion of polio as a White disease was challenged, and Black health professionals, emboldened by a new integrationist epidemiology, demanded that in polio, as in American medicine at large, health care should be provided regardless of race, color, or creed.

Geohydrology of Pipe Spring National Monument area, northern Arizona

USGS Publications Warehouse

Truini, Margot

1999-01-01

Pipe Spring National Monument is on the Arizona Strip, an area between the Utah border to the north and the north rim of the Grand Canyon to the south. Four springs at the base of Winsor Point on Winsor Mountain (known collectively as Pipe Spring) are a part of the historical significance of the monument. The relation between declining discharges from springs in the monument and ground-water development north of the monument was studied to provide information that could be used for management of the monument resources. Ground-water elevations from wells indicate that ground-water movement is from north to south along the west side of a branch of Sevier Fault. Faulting in the areas has downthrown permeable water-bearing sediments relative to impermeable sediments and is evinced by cliffs along the western and northern edges and flat-lying areas to the east. The Navajo Sandstone and Kayenta Formation are the primary water-bearing units on the west side of the fault. The semipermeable sediments of the Chinle and Moenkopi Formations on the east side of the fault inhibit ground-water movement from the west to the east side of the fault. Ground water south of Moccasin Canyon is higher in total dissolved solids than ground water north of Moccasin Canyon. Wells north of Moccasin Canyon are open primarily in the Navajo Sandstone, and wells south of Moccasin Canyon are open primarily in the upper sandstone facies of the Kayenta Formation. A water-budget estimate for the study area indicates a storage deficit of 780 acre-feet per year. This deficit suggests that some recharge may be occurring outside the study area. Oxygen and hydrogen stable- isotopic data suggest no isotopic variation in recharging waters in the study area and surrounding region. Radiocarbon and tritium activities indicate apparent ground-water ages at wells and springs are between 45 and 9,000 years.

Impacts of global warming on phenology of spring leaf unfolding remain stable in the long run.

PubMed

Wang, Huanjiong; Rutishauser, This; Tao, Zexing; Zhong, Shuying; Ge, Quansheng; Dai, Junhu

2017-02-01

The impact of spring temperature forcing on the timing of leaf unfolding of plants (temperature sensitivity, S T ) is one important indicator of how and to what degree plant species track climate change. Fu et al. (Nature 526:104-107, 2015) found that S T has significantly decreased from the 1980-1994 to the 1999-2013 period for seven mid-latitude tree species in Europe. However, long-term changes in S T over the past 60 years are still not clear. Here, using in situ observations of leaf unfolding for seven dominant European tree species, we analyze the temporal change in S T over decadal time scales extending the data series back to 1951. Our results demonstrate that S T shows no statistically significant change within shifting 30-year windows from 1951 to 2013 and remains stable between 1951-1980 and 1984-2013 (3.6 versus 3.7 days °C -1 ). This result suggests that the significant decrease in S T over the past 33 years could not be sustained when examining the trends of phenological responses in the long run. Therefore, we could not conclude that tree spring phenology advances will slow down in the future, and the S T changes in warming scenarios are still uncertain.

Changes in hot spring temperature and hydrogeology of the Alpine Fault hanging wall, New Zealand, induced by distal South Island earthquakes

NASA Astrophysics Data System (ADS)

Cox, S.; Menzies, C. D.; Sutherland, R.; Denys, P. H.; Chamberlain, C. J.; Teagle, D. A. H.

2014-12-01

In response to large distant earthquakes Copland hot spring cooled c.1 °C and changed fluid chemistry. Thermal springs in the Southern Alps, New Zealand, originate through penetration of fluids into a thermal anomaly generated by rapid uplift and exhumation on the Alpine Fault. Copland hot spring (43.629S, 169.946E) is one of the most vigorously flowing, hottest of the springs, discharging strongly effervescent CO2-rich 56-58 °C water at 6 ± 1 Ls-1. Shaking from the Mw7.8 Dusky Sound (Fiordland) 2009 and Mw7.1 Darfield (Canterbury) 2010 earthquakes, 350 and 180 km from the spring respectively, resulted in a characteristic c. 1 °C delayed-cooling over five days. The cooling responses occurred at low shaking intensities (MM III-IV) and seismic energy densities (~10-1 Jm-3) from intermediate-field distances, independent of variations in spectral frequency, without the need for post-seismic recovery before the next cooling occurred. Such shaking can be expected approximately every 1-10 years in central Southern Alps. Observed temperature and fluid chemistry responses are inferred to reflect subtle changes in the fracture permeability of schist mountains adjacent to the spring. Relatively low intensity shaking induced small permanent 10-7-10-6 strains across the Southern Alps - opening fractures which enhance mixing of relatively cool near-surface groundwater with upwelling hot water. Hydrothermal systems situated in places of active deformation, tectonic and topographic stress may be particularly susceptible to earthquake-induced transience, that if monitored may provide important information on difficult to measure hydrogeological properties within active orogens.

Geologic map of the Bartlett Springs Fault Zone in the vicinity of Lake Pillsbury and adjacent areas of Mendocino, Lake, and Glenn Counties, California

USGS Publications Warehouse

Ohlin, Henry N.; McLaughlin, Robert J.; Moring, Barry C.; Sawyer, Thomas L.

2010-01-01

The Lake Pillsbury area lies in the eastern part of the northern California Coast Ranges, along the east side of the transform boundary between the Pacific and North American plates (fig. 1). The Bartlett Springs Fault Zone is a northwest-trending zone of faulting associated with this eastern part of the transform boundary. It is presently active, based on surface creep (Svarc and others, 2008), geomorphic expression, offset of Holocene units (Lienkaemper and Brown, 2009), and microseismicity (Bolt and Oakeshott, 1982; Dehlinger and Bolt, 1984; DePolo and Ohlin, 1984). Faults associated with the Bartlett Springs Fault Zone at Lake Pillsbury are steeply dipping and offset older low to steeply dipping faults separating folded and imbricated Mesozoic terranes of the Franciscan Complex and interleaved rocks of the Coast Range Ophiolite and Great Valley Sequence. Parts of this area were mapped in the late 1970s and 1980s by several investigators who were focused on structural relations in the Franciscan Complex (Lehman, 1978; Jordan, 1975; Layman, 1977; Etter, 1979). In the 1980s the U.S. Geological Survey (USGS) mapped a large part of the area as part of a mineral resource appraisal of two U.S. Forest Service Roadless areas. For evaluating mineral resource potential, the USGS mapping was published at a scale of 1:62,500 as a generalized geologic summary map without a topographic base (Ohlin and others, 1983; Ohlin and Spear, 1984). The previously unpublished mapping with topographic base is presented here at a scale of 1:30,000, compiled with other mapping in the vicinity of Lake Pillsbury. The mapping provides a geologic framework for ongoing investigations to evaluate potential earthquake hazards and structure of the Bartlett Springs Fault Zone. This geologic map includes part of Mendocino National Forest (the Elk Creek Roadless Area) in Mendocino, Glenn, and Lake Counties and is traversed by several U.S. Forest Service Routes, including M1 and M6 (fig. 2). The study

Larger temperature response of autumn leaf senescence than spring leaf-out phenology.

PubMed

Fu, Yongshuo H; Piao, Shilong; Delpierre, Nicolas; Hao, Fanghua; Hänninen, Heikki; Liu, Yongjie; Sun, Wenchao; Janssens, Ivan A; Campioli, Matteo

2018-05-01

Climate warming is substantially shifting the leaf phenological events of plants, and thereby impacting on their individual fitness and also on the structure and functioning of ecosystems. Previous studies have largely focused on the climate impact on spring phenology, and to date the processes underlying leaf senescence and their associated environmental drivers remain poorly understood. In this study, experiments with temperature gradients imposed during the summer and autumn were conducted on saplings of European beech to explore the temperature responses of leaf senescence. An additional warming experiment during winter enabled us to assess the differences in temperature responses of spring leaf-out and autumn leaf senescence. We found that warming significantly delayed the dates of leaf senescence both during summer and autumn warming, with similar temperature sensitivities (6-8 days delay per °C warming), suggesting that, in the absence of water and nutrient limitation, temperature may be a dominant factor controlling the leaf senescence in European beech. Interestingly, we found a significantly larger temperature response of autumn leaf senescence than of spring leaf-out. This suggests a possible larger contribution of delays in autumn senescence, than of the advancement in spring leaf-out, to extending the growing season under future warmer conditions. © 2017 John Wiley & Sons Ltd.

Soil warming effect on net ecosystem exchange of carbon dioxide during the transition from winter carbon source to spring carbon sink in a temperate urban lawn.

PubMed

Zhou, Xiaoping; Wang, Xiaoke; Tong, Lei; Zhang, Hongxing; Lu, Fei; Zheng, Feixiang; Hou, Peiqiang; Song, Wenzhi; Ouyang, Zhiyun

2012-01-01

The significant warming in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations. However, it is less known of the climate feedback of urban lawn in warmed environment. Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing, China. The NEE (negative for uptake) under soil warming treatment (temperature was about 5 degrees C higher than the ambient treatment as a control) was -0.71 micromol/(m2 x sec), the ecosytem was a CO2 sink under soil warming treatment, the lawn ecosystem under the control was a CO2 source (0.13 micromol/(m2 x sec)), indicating that the lawn ecosystem would provide a negative feedback to global warming. There was no significant effect of soil warming on nocturnal NEE (i.e., ecosystem respiration), although the soil temperature sensitivity (Q10) of ecosystem respiration under soil warming treatment was 3.86, much lower than that in the control (7.03). The CO2 uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of alpha (apparent quantum yield) and Amax (maximum rate of photosynthesis). Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period.

Hydrogeology and structure of the Bluewater Springs area south central Montana

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

Padilla, C.E.; Osborne, T.J.

1996-06-01

The Bluewater springs area in south central Montana was the site of oil and gas exploration in the first half of this century. Though no significant oil was found, artesian water wells produced over 3,000 gallons per minute. Artesian springs in the area produce tufa deposits over faulted, northwest dipping Mesozoic and upper Paleozoic sediments. Two new faults were mapped in the vicinity, one of these a high angle vertical fault dissects an anticline. The Tensleep and Madison aquifers (700-1,000 feet deep) leak water to the surface through faults and fractures, producing variable water quality depending on the minerals dissolvedmore » from overlying rock formations. Evaluation of limited aquifer data reveals the following: (1) hydraulic conductivity of 40,000 to 300,000 gpd/ft, (2) hydrostatic head greater than 400 feet above land surface. (3) Total dissolved solids concentrations were 2,370 ppm in Big Bluewater Springs, but only 1,200 ppm in a Tensleep well in the vicinity. Flowing wells 45 to 70 years old have failed leading to major yield reductions, and cessation of flow. Potentially corrosive groundwater coupled with excessive flow velocities and inadequate well construction has likely led to well failures. In response, major uncontrolled alterations of groundwater flow systems have occurred with outbreaks of new springs and sinkholes near failed wells. New wells must be carefully planned, constructed and tested to avoid excessive interference, depressurization and failure.« less

The Study of Fault Lineament Pattern of the Lamongan Volcanic Field Using Gravity Data

NASA Astrophysics Data System (ADS)

Aziz, K. N.; Hartantyo, E.; Niasari, S. W.

2018-04-01

Lamongan Volcano located in Tiris, East Java, possesses geothermal potential energy. The geothermal potential was indicated by the presence of geothermal manifestations such as hot springs. We usedsecondary gravity data from GGMplus. The result of gravity anomaly map shows that there is the lowest gravity anomaly in the center of the study area coinciding with the hot spring location. Gravity data were analyzed using SVD method to identify fault structures. It controls the geothermal fluid pathways. The result of this research shows thatthe type of fault in hot springsisanormal fault with direction NW-SE. The fault lineament pattern along maaris NW-SE.Maar indicates anormal fault. As the result we know that gravity data from GGMplus which analyzed with SVD can be used to determine the type and trend of fault.

The impact of winter and spring temperatures on temperate tree budburst dates: results from an experimental climate manipulation.

PubMed

Fu, Yongshuo H; Campioli, Matteo; Deckmyn, Gaby; Janssens, Ivan A

2012-01-01

Budburst phenology is a key driver of ecosystem structure and functioning, and it is sensitive to global change. Both cold winter temperatures (chilling) and spring warming (forcing) are important for budburst. Future climate warming is expected to have a contrasting effect on chilling and forcing, and subsequently to have a non-linear effect on budburst timing. To clarify the different effects of warming during chilling and forcing phases of budburst phenology in deciduous trees, (i) we conducted a temperature manipulation experiment, with separate winter and spring warming treatments on well irrigated and fertilized saplings of beech, birch and oak, and (ii) we analyzed the observations with five temperature-based budburst models (Thermal Time model, Parallel model, Sequential model, Alternating model, and Unified model). The results show that both winter warming and spring warming significantly advanced budburst date, with the combination of winter plus spring warming accelerating budburst most. As expected, all three species were more sensitive to spring warming than to winter warming. Although the different chilling requirement, the warming sensitivity was not significantly different among the studied species. Model evaluation showed that both one- and two- phase models (without and with chilling, respectively) are able to accurately predict budburst. For beech, the Sequential model reproduced budburst dates best. For oak and birch, both Sequential model and the Thermal Time model yielded good fit with the data but the latter was slightly better in case of high parameter uncertainty. However, for late-flushing species, the Sequential model is likely be the most appropriate to predict budburst data in a future warmer climate.

Hydrogeology and sources of water to select springs in Black Canyon, south of Hoover Dam, Lake Mead National Recreation Area, Nevada and Arizona

USGS Publications Warehouse

Moran, Michael J.; Wilson, Jon W.; Beard, L. Sue

2015-11-03

Several major faults, including the Salt Cedar Fault and the Palm Tree Fault, play an important role in the movement of groundwater. Groundwater may move along these faults and discharge where faults intersect volcanic breccias or fractured rock. Vertical movement of groundwater along faults is suggested as a mechanism for the introduction of heat energy present in groundwater from many of the springs. Groundwater altitudes in the study area indicate a potential for flow from Eldorado Valley to Black Canyon although current interpretations of the geology of this area do not favor such flow. If groundwater from Eldorado Valley discharges at springs in Black Canyon then the development of groundwater resources in Eldorado Valley could result in a decrease in discharge from the springs. Geology and structure indicate that it is not likely that groundwater can move between Detrital Valley and Black Canyon. Thus, the development of groundwater resources in Detrital Valley may not result in a decrease in discharge from springs in Black Canyon.

Seasonal warming of the Middle Atlantic Bight Cold Pool

NASA Astrophysics Data System (ADS)

Lentz, S. J.

2017-02-01

The Cold Pool is a 20-60 m thick band of cold, near-bottom water that persists from spring to fall over the midshelf and outer shelf of the Middle Atlantic Bight (MAB) and Southern Flank of Georges Bank. The Cold Pool is remnant winter water bounded above by the seasonal thermocline and offshore by warmer slope water. Historical temperature profiles are used to characterize the average annual evolution and spatial structure of the Cold Pool. The Cold Pool gradually warms from spring to summer at a rate of order 1°C month-1. The warming rate is faster in shallower water where the Cold Pool is thinner, consistent with a vertical turbulent heat flux from the thermocline to the Cold Pool. The Cold Pool warming rate also varies along the shelf; it is larger over Georges Bank and smaller in the southern MAB. The mean turbulent diffusivities at the top of the Cold Pool, estimated from the spring to summer mean heat balance, are an order of magnitude larger over Georges Bank than in the southern MAB, consistent with much stronger tidal mixing over Georges Bank than in the southern MAB. The stronger tidal mixing causes the Cold Pool to warm more rapidly over Georges Bank and the eastern New England shelf than in the New York Bight or southern MAB. Consequently, the coldest Cold Pool water is located in the New York Bight from late spring to summer.

Spring Hydrology Determines Summer Net Carbon Uptake in Northern Ecosystems

NASA Technical Reports Server (NTRS)

Yi, Yonghong; Kimball, John; Reichle, Rolf H.

2014-01-01

Increased photosynthetic activity and enhanced seasonal CO2 exchange of northern ecosystems have been observed from a variety of sources including satellite vegetation indices (such as the Normalized Difference Vegetation Index; NDVI) and atmospheric CO2 measurements. Most of these changes have been attributed to strong warming trends in the northern high latitudes (greater than or equal to 50N). Here we analyze the interannual variation of summer net carbon uptake derived from atmospheric CO2 measurements and satellite NDVI in relation to surface meteorology from regional observational records. We find that increases in spring precipitation and snow pack promote summer net carbon uptake of northern ecosystems independent of air temperature effects. However, satellite NDVI measurements still show an overall benefit of summer photosynthetic activity from regional warming and limited impact of spring precipitation. This discrepancy is attributed to a similar response of photosynthesis and respiration to warming and thus reduced sensitivity of net ecosystem carbon uptake to temperature. Further analysis of boreal tower eddy covariance CO2 flux measurements indicates that summer net carbon uptake is positively correlated with early growing-season surface soil moisture, which is also strongly affected by spring precipitation and snow pack based on analysis of satellite soil moisture retrievals. This is attributed to strong regulation of spring hydrology on soil respiration in relatively wet boreal and arctic ecosystems. These results document the important role of spring hydrology in determining summer net carbon uptake and contrast with prevailing assumptions of dominant cold temperature limitations to high-latitude ecosystems. Our results indicate potentially stronger coupling of boreal/arctic water and carbon cycles with continued regional warming trends.

Spring plant phenology and false springs in the conterminous US during the 21st century

USGS Publications Warehouse

Allstadt, Andrew J.; Vavrus, Stephen J.; Heglund, Patricia J.; Pidgeon, Anna M.; Thogmartin, Wayne E.; Radeloff, Volker C.

2015-01-01

The onset of spring plant growth has shifted earlier in the year over the past several decades due to rising global temperatures. Earlier spring onset may cause phenological mismatches between the availability of plant resources and dependent animals, and potentially lead to more false springs, when subsequent freezing temperatures damage new plant growth. We used the extended spring indices to project changes in spring onset, defined by leaf out and by first bloom, and predicted false springs until 2100 in the conterminous United States (US) using statistically-downscaled climate projections from the Coupled Model Intercomparison Project 5 ensemble. Averaged over our study region, the median shift in spring onset was 23 days earlier in the Representative Concentration Pathway 8.5 scenario with particularly large shifts in the Western US and the Great Plains. Spatial variation in phenology was due to the influence of short-term temperature changes around the time of spring onset versus season long accumulation of warm temperatures. False spring risk increased in the Great Plains and portions of the Midwest, but remained constant or decreased elsewhere. We conclude that global climate change may have complex and spatially variable effects on spring onset and false springs, making local predictions of change difficult.

Three studies on ponderosa pine management on the Warm Springs Indian Reservation: stocking control in uneven-aged stands, forest products from fire-damage trees, and fuels reduction

Treesearch

John V. Arena

2005-01-01

Over 60,000 acres of ponderosa pine (Pinus ponderosa P. and C. Lawson) forest on the Warm Springs Indian Reservation (WSIR) in Oregon are managed using an uneven-age system. Three on-going studies on WSIR address current issues in the management of pine forests: determining levels of growing stock for uneven-age management, fire effects on wood...

Are Sierran Lakes Warming as a Result of Climate Change? The Effects of Climate Warming and Variation in Precipitation on Water Temperature in a Snowmelt-Dominated Lake

NASA Astrophysics Data System (ADS)

Sadro, S.; Melack, J. M.; Sickman, J. O.; Skeen, K.

2016-12-01

Water temperature regulates a broad range of fundamental ecosystem processes in lakes. While climate can be an important factor regulating lake temperatures, heterogeneity in the warming response of lakes is large, and variation in precipitation is rarely considered. We analyzed three decades of climate and water temperature data from a high-elevation catchment in the southern Sierra Nevada of California to illustrate the magnitude of warming taking place during different seasons and the role of precipitation in regulating lake temperatures. Significant climate warming trends were evident during all seasons except spring. Nighttime rates of climate warming were approximately 25% higher than daytime rates. Spatial patterns in warming were elevation dependent, with rates of temperature increase higher at sites above 2800 m.a.s.l. than below. Although interannual variation in snow deposition was high, the frequency and severity of recent droughts has contributed to a significant 3.4 mm year -1 decline in snow water equivalent over the last century. Snow accumulation, more than any other climate factor, regulated lake temperature; 94% of variation in summer lake temperature was regulated by precipitation as snow. For every 100 mm decrease in snow water equivalent there was a 0.62 ° increase in lake temperature. Drought years amplify warming in lakes by reducing the role of cold spring meltwaters in lake energy budgets and prolonging the ice-free period during which lakes warm. The combination of declining winter snowpack and warming air temperatures has the capacity to amplify the effect of climate warming on lake temperatures during drought years. Interactions among climatic factors need to be considered when evaluating ecosystem level effects, especially in mountain regions. For mountain lakes already affected by drought, continued climate warming during spring and autumn has the greatest potential to impact mean lake temperatures.

Hood River Production Program Monitoring and Evaluation (M&E) - Confederated Tribes of Warm Springs : Annual Report For Fiscal Year, October 2007 – September 2008.

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

Gerstenberger, Ryan

2009-07-27

This progress report describes work performed by the Confederated Tribes of Warm Springs (CTWSRO) portion of the Hood River Production Program Monitoring and Evaluation Project (HRPP) during the 2008 fiscal year. A total of 64,736 hatchery winter steelhead, 12,108 hatchery summer steelhead, and 68,426 hatchery spring Chinook salmon smolts were acclimated and released in the Hood River basin during the spring. The HRPP exceeded program goals for a release of and 50,000 winter steelhead but fell short of the steelhead release goals of 30,000 summer steelhead and 75,000 spring Chinook in 2008. Passive Integrated Transponders (PIT) tags were implanted inmore » 6,652 hatchery winter steelhead, and 1,196 hatchery summer steelhead, to compare migratory attributes and survival rates of hatchery fish released into the Hood River. Water temperatures were recorded at six locations within the Hood River subbasin to monitor for compliance with Oregon Department of Environmental Quality water quality standards. A preseason spring Chinook salmon adult run forecast was generated, which predicted an abundant return adequate to meet escapement goal and brood stock needs. As a result the tribal and sport fisheries were opened. A tribal creel was conducted from May 22 to July 18 during which an estimated 172 spring Chinook were harvested. One hundred sixteen Spring Chinook salmon redds were observed and 72 carcasses were inspected on 19.4 miles of spawning grounds throughout the Hood River Basin during 2008. Annual salvage operations were completed in two irrigation canals resulting in the liberation of 1,641 fish back to the Hood River.« less

Geochemical Influence on Microbial Diversity in the Warm, Salty, Stinking Spring, Utah, USA

NASA Astrophysics Data System (ADS)

Spear, J. R.

2012-12-01

Little is known of the geochemistry and microbiology in the Stinking Springs, a sulfidic, saline, warm spring northeast of the Great Salt Lake, Utah. The International Geobiology Course of 2012 investigated the geochemistry, lipid abundances, dissolved inorganic carbon (DIC) uptake rates and microbial diversity on different kinds of samples from a number of locations in the spring. The measured pH, temperature, salinity, and sulfide concentration along the 100 m flow path ranged from 6.64-7.77, 40-28° C, 2.9-2.2%, and 250 μM - negligible, respectively. Five sites were selected along the flow path and within each site microbial mats were sub-sampled according to their morphological characteristics; a range from floating to streamer-style in zones of higher flow rates to highly-layered mats in low- or sheet-flow zones. Geochemical characterization of the above plus metals, anions and cations were conducted at each site. Genomic DNA was extracted from each microbial sample / layer, and 16S rRNA genes were amplified and subjected to pyrosequencing. Fatty acids and pigments were extracted from the mat samples / layers and analyzed by liquid chromatography and mass spectrometry for lipid / pigment composition. Bicarbonate uptake rates for mat samples / layers were determined with 24 hour light and dark incubations of 13HCO3-spiked spring water. Microbial diversity varied by site and was generally high in all three domains of life with phototrophs, sulfur oxidizers, sulfate reducers, methanogens, and other bacteria / archaea identified by 16S rRNA gene sequence. Diatoms, identified by both microscopy and lipid analyses were found to increase in abundance with distance from the source. Methanogens were generally more abundant in deeper mat laminae and underlying sediments. Photoheterotrophs were found in all mat layers. Microbial diversity increased significantly with depth at most sites. In addition, two distinct microbial streamers were also identified and

NOVA Spring 2000 Teacher's Guide.

ERIC Educational Resources Information Center

Colombo, Luann; Gregoire, Tanya; Ransick, Kristina; Sammons, Fran Lyons; Sammons, James

This teacher's guide complements six programs that aired on the Public Broadcasting System (PBS) in the spring of 2000. Programs include: (1) "Lost on Everest"; (2) "Lost Tribes of Israel"; (3) "Crocodiles"; (4) "Lost at Sea: The Search for Longitude"; (5) "Global Warming"; and (6) "Secrets of…

Salt movements and faulting of the overburden - can numerical modeling predict the fault patterns above salt structures?

NASA Astrophysics Data System (ADS)

Clausen, O. R.; Egholm, D. L.; Wesenberg, R.

2012-04-01

Salt deformation has been the topic of numerous studies through the 20th century and up until present because of the close relation between commercial hydrocarbons and salt structure provinces of the world (Hudec & Jackson, 2007). The fault distribution in sediments above salt structures influences among other things the productivity due to the segmentation of the reservoir (Stewart 2006). 3D seismic data above salt structures can map such fault patterns in great detail and studies have shown that a variety of fault patterns exists. Yet, most patterns fall between two end members: concentric and radiating fault patterns. Here we use a modified version of the numerical spring-slider model introduced by Malthe-Sørenssen et al.(1998a) for simulating the emergence of small scale faults and fractures above a rising salt structure. The three-dimensional spring-slider model enables us to control the rheology of the deforming overburden, the mechanical coupling between the overburden and the underlying salt, as well as the kinematics of the moving salt structure. In this presentation, we demonstrate how the horizontal component on the salt motion influences the fracture patterns within the overburden. The modeling shows that purely vertical movement of the salt introduces a mesh of concentric normal faults in the overburden, and that the frequency of radiating faults increases with the amount of lateral movements across the salt-overburden interface. The two end-member fault patterns (concentric vs. radiating) can thus be linked to two different styles of salt movement: i) the vertical rising of a salt indenter and ii) the inflation of a 'salt-balloon' beneath the deformed strata. The results are in accordance with published analogue and theoretical models, as well as natural systems, and the model may - when used appropriately - provide new insight into how the internal dynamics of the salt in a structure controls the generation of fault patterns above the structure. The

Three-Dimensional Analysis of dike/fault interaction at Mono Basin (California) using the Finite Element Method

NASA Astrophysics Data System (ADS)

La Marra, D.; Battaglia, M.

2013-12-01

Mono Basin is a north-trending graben that extends from the northern edge of Long Valley caldera towards the Bodie Hills and is bounded by the Cowtrack Mountains on the east and the Sierra Nevada on the west. The Mono-Inyo Craters volcanic chain forms a north-trending zone of volcanic vents extending from the west moat of the Long Valley caldera to Mono Lake. The Hartley Springs fault transects the southern Mono Craters-Inyo Domes area between the western part of the Long Valley caldera and June Lake. Stratigraphic data suggest that a series of strong earthquakes occurred during the North Mono-Inyo eruption sequence of ~1350 A.D. The spatial and temporal proximity between Hartley Springs Fault motion and the North Mono-Inyo eruption sequence suggests a possible relation between seismic events and eruptions. We investigate the interactions between slip along the Hartley Springs fault and dike intrusion beneath the Mono-Inyo craters using a three-dimensional finite element model of the Mono Basin. We employ a realistic representation of the Basin that includes topography, vertical and lateral heterogeneities of the crust, contact relations between fault planes, and a physical model of the pressure required to propagate the dike. We estimate (a) the distribution of Coulomb stress changes to study the influence of dike intrusion on Hartley Springs fault, and (b) the local stress and volumetric dilatation changes to understand how fault slip may influence the propagation of a dike towards the surface.

New Approaches for Responsible Management of Offshore Springs in Semi-arid Regions

NASA Astrophysics Data System (ADS)

Shaban, Amin; de Jong, Carmen; Al-Sulaimani, Zaher

2017-04-01

In arid and semi-arid regions, such as the Mediterranean and Gulf Region where water is scarce water demand has been exacerbated and become a major environmental challenge. Presently there is massive pressure to develop new water sources to alleviate existing water stress. In the quest for more freshwater even groundwater discharge into the sea in the form of "off-shore freshwater springs" (or submarine groundwater discharge) has been contemplated as a potential source of unconventional water in coastal zones. Offshore-springs are derived from aquifers with complex geological controls mainly in the form of faults and karst conduits. Representing a border-line discipline, they have been poorly studied with only few submarine groundwater monitoring sites existing worldwide. Recently, innovative techniques have been developed enabling springs to be detected via remote sensing such as airborne surveys or satellite images. "Thermal Anomalies" can be clearly identified as evidence for groundwater discharge into the marine environment. A diversity of groundwater routes along which off-shore springs are fed from land sources can be recognized and near-shore and offshore springs differentiated and classified according to their geometry. This is well pronounced along the coast of Lebanon and offshore of Oman. Offshore springs play an important role in the marine ecosystem as natural sources of mercury, metals, nutrients, dissolved carbon species and in cooling or warming ocean water. However, they are extremely sensitive to variations in qualitative and quantitative water inputs triggered by climate change and anthropogenic impacts especially in their recharge zones. Pollutants such as sewage, detergents, heavy metals or herbicides that negatively affect water quality of offshore springs can transit the groundwater rapidly. Recently these springs have also been severely affected by uncontrolled water abstraction from land aquifers. In Bahrain, overpumping combined with

The Hayward-Rodgers Creek Fault System: Learning from the Past to Forecast the Future

NASA Astrophysics Data System (ADS)

Schwartz, D. P.; Lienkaemper, J. J.; Hecker, S.

2007-12-01

The San Francisco Bay area is located within the Pacific-North American plate boundary. As a result, the region has the highest density of active faults per square kilometer of any urban center in the US. Between the Farallon Islands and Livermore, the faults of the San Andreas fault system are slipping at a rate of about 40 mm/yr. Approximately 25 percent of this rate is accommodated by the Hayward fault and its continuation to the north, the Rodgers Creek fault. The Hayward fault extends 88 km from Warm Springs on the south into San Pablo Bay on the north, traversing the most heavily urbanized part of the Bay Area. The Rodgers Creek fault extends another 63 km, passing through Santa Rosa and ending south of Healdsburg. Geologic, seismologic, and geodetic studies during the past ten years have significantly increased our knowledge of this system. In particular, paleoseismic studies of the timing of past earthquakes have provided critical new information for improving our understanding of how these faults may work in time and space, and for estimating the probability of future earthquakes. The most spectacular result is an 11-earthquake record on the southern Hayward fault that extends back to A.D. 170. It suggests an average time interval between large earthquakes of 170 years for this period, with a shorter interval of 140 years for the five most recent earthquakes. Paleoseismic investigations have also shown that prior to the most recent large earthquake on the southern Hayward fault in 1868, large earthquakes occurred on the southern Hayward fault between 1658 and1786, on the northern Hayward fault between 1640 and 1776, and on the Rodgers Creek fault between 1690 and 1776. These could have been three separate earthquakes. However, the overlapping radiocarbon dates for these paleoearthquakes allow the possibility that these faults may have ruptured together in several different combinations: a combined southern and northern Hayward fault earthquake, a Rodgers

The false spring of 2012, earliest in North American record

USGS Publications Warehouse

Ault, T.R.; Henebry, G.M.; de Beurs, K. M.; Schwartz, M.D.; Betancourt, Julio L.; Moore, David

2013-01-01

Phenology - the study of recurring plant and animal life cycle stages, especially their timing and relationships with weather and climate - is becoming an essential tool for documenting, communicating, and anticipating the consequences of climate variability and change. For example, March 2012 broke numerous records for warm temperatures and early flowering in the United States [Karl et al., 2012; Elwood et al., 2013]. Many regions experienced a “false spring,” a period of weather in late winter or early spring sufficiently mild and long to bring vegetation out of dormancy prematurely, rendering it vulnerable to late frost and drought.As global climate warms, increasingly warmer springs may combine with the random climatological occurrence of advective freezes, which result from cold air moving from one region to another, to dramatically increase the future risk of false springs, with profound ecological and economic consequences [e.g., Gu et al., 2008; Marino et al., 2011; Augspurger, 2013]. For example, in the false spring of 2012, an event embedded in long-term trends toward earlier spring [e.g., Schwartz et al., 2006], the frost damage to fruit trees totaled half a billion dollars in Michigan alone, prompting the federal government to declare the state a disaster area [Knudson, 2012].

Fontibacillus aquaticus gen. nov., sp. nov., isolated from a warm spring.

PubMed

Saha, P; Krishnamurthi, S; Bhattacharya, A; Sharma, R; Chakrabarti, T

2010-02-01

A novel facultatively anaerobic strain, designated GPTSA 19(T), was isolated from a warm spring and characterized using a polyphasic approach. The strain behaved as Gram-negative in the Gram staining procedure but showed a Gram-positive reaction in the aminopeptidase test. The novel strain was a mesophilic rod with ellipsoidal endospores. On the basis of 16S rRNA gene sequence analysis, the strain showed closest similarity (96.0 %) with Paenibacillus motobuensis MC10(T). The gene sequence similarity of the novel strain with other species of the genus Paenibacillus was <95.8 %. The novel strain also had PAEN 515F and 682F signature sequence stretches in the 16S rRNA gene that are usually found in most species of the genus Paenibacillus. The strain possessed anteiso-C(15 : 0) as the major fatty acid and MK-7 as the predominant menaquinone. Polar lipids included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), six unknown phospholipids (PLs), one aminophospholipid (PN), three glycolipids (GLs), two aminolipids (ALs), one aminophosphoglycolipid (APGL) and three unknown lipids (ULs). The polar lipid profile of the novel strain, especially as regards ALs, GLs and PLs, distinguished it from the recognized type species of the genus Paenibacillus, Paenibacillus polymyxa, as well as from its closest relative P. motobuensis. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the new strain merits the rank of a novel genus for which the name Fontibacillus gen. nov. is proposed. The type species of the new genus is Fontibacillus aquaticus gen. nov., sp. nov. with the type strain GPTSA 19(T) (=MTCC 7155(T)=DSM 17643(T)).

Structural Controls of Neal Hot Springs Geothermal Field, Malhuer County, Oregon

NASA Astrophysics Data System (ADS)

Edwards, J. H.; Faulds, J. E.

2012-12-01

Detailed mapping (1:24,000) of the Neal Hot Springs area (90 km2) in eastern Oregon is part of a larger study of geothermal systems in the Basin and Range, which focuses on the structural controls of geothermal activity. The study area lies within the intersection of two regional grabens, the middle-late Miocene, N-striking, Oregon-Idaho graben and younger late Miocene to Holocene, NW-striking, western Snake River Plain graben. The geothermal field is marked by Neal Hot Springs, which effuse from opaline sinter mounds just north of Bully Creek. Wells producing geothermal fluids, with temperatures at 138°C, intersect a major, W-dipping, NNW-striking, high-angle normal fault at depths of 850-915 m. Displacement along this structure dies southward, with likely horse-tailing, which commonly produces high fracture density and a zone of high permeability conducive for channeling hydrothermal fluids. Mapping reveals that the geothermal resource lies within a local, left step-over. 'Hard-linkage' between strands of the left-stepping normal fault, revealed through a study of well chips and well logs, occurs through two concealed structures. Both are W-striking faults, with one that runs parallel to Cottonwood Creek and one 0.5 km N of the creek. Injection wells intersect these two transverse structures within the step-over. Stepping and displacement continue to the NW of the known geothermal field, along W-dipping, N-striking faults that cut lower to middle Miocene Hog Creek Formation, consisting of silicic and mafic volcanic rocks. These N-striking faults were likely initiated during initial Oregon-Idaho graben subsidence (15.3-15.1 Ma), with continued development through late Miocene. Bully Creek Formation deposits, middle to upper Miocene lacustrine and pyroclastic rocks, concomitantly filled the sub half-grabens, and they dip gently to moderately eastward. Younger, western Snake River Plain deposits, upper Miocene to Pliocene fluvial, lacustrine, and pyroclastic rocks

Fault Networks in the Northwestern Albuquerque Basin and Their Potential Role in Controlling Mantle CO2 Degassing and Fluid Migration from the Valles Caldera

NASA Astrophysics Data System (ADS)

Smith, J. R.; Crossey, L. J.; Karlstrom, K. E.; Fischer, T. P.; Lee, H.; McGibbon, C. J.

2015-12-01

The Rio Grande rift (RGR) has Quaternary and active volcanism and faulting that provide a field laboratory for examining links between mantle degassing and faults as fluid conduits. Diffuse and spring CO2 flux measurements were taken at 6 sites in the northwestern Albuquerque Basin (NWAB) and Valles caldera geothermal system. All sites progress to the southwest from the 1.25 Ma Valles caldera, down the rift-related Jemez fault network, to intersect with the Nacimiento fault system. Mantle CO2 and He degassing are well documented at 5 of 6 sites, with decreasing 3He/4He ratios away from the caldera. The instrument used to measure CO2 flux was an EGM-4 CO2 gas analyzer (PP systems) with an accumulation chamber. Carbonic springs at Penasco Springs (PS) and San Ysidro (SY), and the carbonate-cemented Sand Hill Fault (SHF) were targeted, all near the western border of the RGR. The SHF has no spring activity, had the smallest maximum flux of all the sites (8 g/m2d), but carbonate along the fault zone (<2 m wide) attest to past CO2 flux. The other two sites are equal distance (30-40 km) between the SHF site and Valles caldera sites. These sites have active carbonic springs that precipitate travertine mounds. Our work suggests these sites reflect intersections of the Nacimiento fault with NE trending faults that connect to the Jemez fault network. The maximum diffuse flux recorded at SY (297 g/m2d) and PS (25 g/m2d) are high, especially along the fault and near springs. At SY and PS the instruments capacity was exceeded (2,400 g/m2d) at 6 of 9 springs. Interpretations indicate a direct CO2 flux through a fault-related artesian aquifer system that is connected to magmatic gases from the caldera. Maximum diffuse flux measurements of Alamo Canyon (20,906 g/m2d), Sulphur Springs (2,400 g/m2d) and Soda Dam (1,882 g/m2d) at Valles caldera geothermal sites are comparable to Yellowstone geothermal systems. We use geospatial analysis and local geologic mapping to examine

Southern Hemisphere and deep-sea warming led deglacial atmospheric CO2 rise and tropical warming.

PubMed

Stott, Lowell; Timmermann, Axel; Thunell, Robert

2007-10-19

Establishing what caused Earth's largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. We determined the chronology of high- and low-latitude climate change at the last glacial termination by radiocarbon dating benthic and planktonic foraminiferal stable isotope and magnesium/calcium records from a marine core collected in the western tropical Pacific. Deep-sea temperatures warmed by approximately 2 degrees C between 19 and 17 thousand years before the present (ky B.P.), leading the rise in atmospheric CO2 and tropical-surface-ocean warming by approximately 1000 years. The cause of this deglacial deep-water warming does not lie within the tropics, nor can its early onset between 19 and 17 ky B.P. be attributed to CO2 forcing. Increasing austral-spring insolation combined with sea-ice albedo feedbacks appear to be the key factors responsible for this warming.

The future of spring bud burst: looking at the possibilities

Treesearch

Noreen Parks; Connie Harrington; Brad St. Clair;  Peter.  Gould

2010-01-01

The timing of spring budburst in woody plants impacts not only the subsequent seasonal growth for individual trees, but also their associated biological community. As winter and spring temperatures have warmed under the changing climate, in many species budburst has been happening earlier in the year. Understanding the long-term effects of this shift and adapting...

Thermal springs of Malaysia and their potentialdevelopment

NASA Astrophysics Data System (ADS)

Rahim Samsudin, Abdul; Hamzah, Umar; Rahman, Rakmi Ab.; Siwar, Chamhuri; Fauzi Mohd. Jani, Mohd; Othman, Redzuan

The study on the potential development of hot springs for the tourism industry in Malaysiawas conducted. Out of the 40 hot springs covered, the study identified 9 hot springs having a high potential for development, 14 having medium potential and the remaining 17 having low or least potential for development. This conclusion was arrived at after considering the technical and economic feasibility of the various hot springs. Technical feasibility criteria includes geological factors, water quality, temperature and flow rate. The economic feasibility criteria considers measures such as accessibility, current and market potentials in terms of visitors, surrounding attractions and existing inventory and facilities available. A geological input indicates that high potential hot springs are located close to or within the granite body and associated with major permeable fault zones. They normally occur at low elevation adjacent to topographic highs. High potential hot springs are also characterised by high water temperature, substantial flowrate and very good water quality which is important for water-body contact activities such as soaking. Economic criteria for high potential hot springs are associated with good accessibility, good market, good surrounding attractions like rural and village setting and well developed facilities and infrastructures.

The SCEC 3D Community Fault Model (CFM-v5): An updated and expanded fault set of oblique crustal deformation and complex fault interaction for southern California

NASA Astrophysics Data System (ADS)

Nicholson, C.; Plesch, A.; Sorlien, C. C.; Shaw, J. H.; Hauksson, E.

2014-12-01

Southern California represents an ideal natural laboratory to investigate oblique deformation in 3D owing to its comprehensive datasets, complex tectonic history, evolving components of oblique slip, and continued crustal rotations about horizontal and vertical axes. As the SCEC Community Fault Model (CFM) aims to accurately reflect this 3D deformation, we present the results of an extensive update to the model by using primarily detailed fault trace, seismic reflection, relocated hypocenter and focal mechanism nodal plane data to generate improved, more realistic digital 3D fault surfaces. The results document a wide variety of oblique strain accommodation, including various aspects of strain partitioning and fault-related folding, sets of both high-angle and low-angle faults that mutually interact, significant non-planar, multi-stranded faults with variable dip along strike and with depth, and active mid-crustal detachments. In places, closely-spaced fault strands or fault systems can remain surprisingly subparallel to seismogenic depths, while in other areas, major strike-slip to oblique-slip faults can merge, such as the S-dipping Arroyo Parida-Mission Ridge and Santa Ynez faults with the N-dipping North Channel-Pitas Point-Red Mountain fault system, or diverge with depth. Examples of the latter include the steep-to-west-dipping Laguna Salada-Indiviso faults with the steep-to-east-dipping Sierra Cucapah faults, and the steep southern San Andreas fault with the adjacent NE-dipping Mecca Hills-Hidden Springs fault system. In addition, overprinting by steep predominantly strike-slip faulting can segment which parts of intersecting inherited low-angle faults are reactivated, or result in mutual cross-cutting relationships. The updated CFM 3D fault surfaces thus help characterize a more complex pattern of fault interactions at depth between various fault sets and linked fault systems, and a more complex fault geometry than typically inferred or expected from

Hydrogeochemical response of groundwater springs during central Italy earthquakes (24 August 2016 and 26-30 October 2016)

NASA Astrophysics Data System (ADS)

Archer, Claire; Binda, Gilberto; Terrana, Silvia; Gambillara, Roberto; Michetti, Alessandro; Noble, Paula; Petitta, Marco; Rosen, Michael; Pozzi, Andrea; Bellezza, Paolo; Brunamonte, Fabio

2017-04-01

Co-seismic hydrological and chemical response at groundwater springs following strong earthquakes is a significant concern in the Apennines, a region in central Italy characterized by regional karstic groundwater systems interacting with active normal faults capable of producing Mw 6.5 to 7.0 seismic events. These aquifers also provide water supply to major metropolitan areas in the region. On August 24, 2016, a Mw 6.0 earthquake hit Central Italy in the area where Latium joins Umbria, Marche and Abruzzi; this was immediately followed one hour later by a Mw 5.4 shock. The epicenter of the event was located at the segment boundary between the Mt. Vettore and Mt. Laga faults. On October 26, 2016 and on October 30, 2016, three other big shocks (Mw 5.5, Mw 6.0 and Mw 6.5) ruptured again the Vettore Fault and its NW extension. Immediately after Aug. 24, we sampled springs discharging different aquifers in the Rieti area, including the Peschiera spring, which feeds the aqueduct of Rome. Thermal springs connected with deep groundwater flowpaths were also sampled. These springs, sampled previously in 2014 and 2015, provide some pre-earthquake data. Moreover, we sampled 4 springs along the Mt. Vettore fault system: 3 small springs at Forca di Presta, close to the trace of the earthquake surface ruptures, and two in Castel Sant'Angelo sul Nera. The latter are feeding the Nera aqueduct and the Nerea S.p.A. mineral water plant, which also kindly allowed us to collect bottled water samples from the pre-seismic period. The aim of this study is to evaluate the strong earthquake sequence effects on the hydrochemistry and flow paths of groundwater from different aquifer settings based on analysis before and after seismic events. The comparison between the responses of springs ca. 40 km from the epicenter (Rieti basin) and the springs located near the epicenter (Castelsantangelo sul Nera and Forca di Presta) is especially significant for understanding the resilience of groundwater

Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow

PubMed Central

Ganjurjav, Hasbagan; Gao, Qingzhu; Schwartz, Mark W.; Zhu, Wenquan; Liang, Yan; Li, Yue; Wan, Yunfan; Cao, Xujuan; Williamson, Matthew A.; Jiangcun, Wangzha; Guo, Hongbao; Lin, Erda

2016-01-01

Since 2000, the phenology has advanced in some years and at some locations on the Qinghai-Tibetan Plateau, whereas it has been delayed in others. To understand the variations in spring vegetation growth in response to climate, we conducted both regional and experimental studies on the central Qinghai-Tibetan Plateau. We used the normalized difference vegetation index to identify correlations between climate and phenological greening, and found that greening correlated negatively with winter-spring time precipitation, but not with temperature. We used open top chambers to induce warming in an alpine meadow ecosystem from 2012 to 2014. Our results showed that in the early growing season, plant growth (represented by the net ecosystem CO2 exchange, NEE) was lower in the warmed plots than in the control plots. Late-season plant growth increased with warming relative to that under control conditions. These data suggest that the response of plant growth to warming is complex and non-intuitive in this system. Our results are consistent with the hypothesis that moisture limitation increases in early spring as temperature increases. The effects of moisture limitation on plant growth with increasing temperatures will have important ramifications for grazers in this system. PMID:26983697

Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow

NASA Astrophysics Data System (ADS)

Ganjurjav, Hasbagan; Gao, Qingzhu; Schwartz, Mark W.; Zhu, Wenquan; Liang, Yan; Li, Yue; Wan, Yunfan; Cao, Xujuan; Williamson, Matthew A.; Jiangcun, Wangzha; Guo, Hongbao; Lin, Erda

2016-03-01

Since 2000, the phenology has advanced in some years and at some locations on the Qinghai-Tibetan Plateau, whereas it has been delayed in others. To understand the variations in spring vegetation growth in response to climate, we conducted both regional and experimental studies on the central Qinghai-Tibetan Plateau. We used the normalized difference vegetation index to identify correlations between climate and phenological greening, and found that greening correlated negatively with winter-spring time precipitation, but not with temperature. We used open top chambers to induce warming in an alpine meadow ecosystem from 2012 to 2014. Our results showed that in the early growing season, plant growth (represented by the net ecosystem CO2 exchange, NEE) was lower in the warmed plots than in the control plots. Late-season plant growth increased with warming relative to that under control conditions. These data suggest that the response of plant growth to warming is complex and non-intuitive in this system. Our results are consistent with the hypothesis that moisture limitation increases in early spring as temperature increases. The effects of moisture limitation on plant growth with increasing temperatures will have important ramifications for grazers in this system.

Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow.

PubMed

Ganjurjav, Hasbagan; Gao, Qingzhu; Schwartz, Mark W; Zhu, Wenquan; Liang, Yan; Li, Yue; Wan, Yunfan; Cao, Xujuan; Williamson, Matthew A; Jiangcun, Wangzha; Guo, Hongbao; Lin, Erda

2016-03-17

Since 2000, the phenology has advanced in some years and at some locations on the Qinghai-Tibetan Plateau, whereas it has been delayed in others. To understand the variations in spring vegetation growth in response to climate, we conducted both regional and experimental studies on the central Qinghai-Tibetan Plateau. We used the normalized difference vegetation index to identify correlations between climate and phenological greening, and found that greening correlated negatively with winter-spring time precipitation, but not with temperature. We used open top chambers to induce warming in an alpine meadow ecosystem from 2012 to 2014. Our results showed that in the early growing season, plant growth (represented by the net ecosystem CO2 exchange, NEE) was lower in the warmed plots than in the control plots. Late-season plant growth increased with warming relative to that under control conditions. These data suggest that the response of plant growth to warming is complex and non-intuitive in this system. Our results are consistent with the hypothesis that moisture limitation increases in early spring as temperature increases. The effects of moisture limitation on plant growth with increasing temperatures will have important ramifications for grazers in this system.

Hot springs of the central Sierra Nevada, California

USGS Publications Warehouse

Mariner, R.H.; Presser, T.S.; Evans, William C.

1977-01-01

Thermal springs of the central Sierra Nevada issue dilute to slightly saline sodium chloride, sodium bicarbonate, or sodium mixed-anion waters ranging in pH from 6.4 to 9.3. The solubility of chalcedony appears to control the silica concentration in most of the spring waters. Fales Hot Springs may be associated with a higher temperature aquifer, 150 degrees Celsius or more, in which quartz is controlling the silica concentration. Carbon dioxide is the predominant gas escaping from Fales Hot Springs, the unnamed hot spring on the south side of Mono Lake, and the two thermal springs near Bridgeport. Most of the other thermal springs issue small amounts of gas consisting principally of nitrogen. Methane is the major component of the gas escaping from the unnamed spring on Paoha Island in Mono Lake. The deuterium and oxygen isotopic composition of most of the thermal waters are those expected for local meteoric water which has undergone minor water-rock reaction. The only exceptions are the hot spring on Paoha Island in Mono Lake and perhaps the unnamed warm spring (south side of Mono Lake) which issues mixtures of thermal water and saline lake water. (Woodard-USGS)

Slip and Dilation Tendency Anlysis of Neal Hot Springs Geothermal Area

DOE Data Explorer

Faulds, James E.

2013-12-31

Slip and Dilation Tendency in focus areas Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids. The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface: Ts = τ / σn (Morris et al., 1996). Dilation tendency is defined by the stress acting normal to a given surface: Td = (σ1-σn) / (σ1-σ3) (Ferrill et al., 1999). Slip and dilation were calculated using 3DStress (Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential. Stress Magnitudes and directions Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998

2D resistivity imaging and magnetic survey for characterization of thermal springs: A case study of Gergedi thermal springs in the northwest of Wonji, Main Ethiopian Rift, Ethiopia

NASA Astrophysics Data System (ADS)

Abdulkadir, Yahya Ali; Eritro, Tigistu Haile

2017-09-01

Electrical resistivity imaging and magnetic surveys were carried out at Gergedi thermal springs, located in the Main Ethiopian Rift, to characterize the geothermal condition of the area. The area is geologically characterized by alluvial and lacustrine deposits, basaltic lava, ignimbrites, and rhyolites. The prominent structural feature in this part of the Main Ethiopian Rift, the SW -NE trending structures of the Wonji Fault Belt System, crosse over the study area. Three lines of imaging data and numerous magnetic data, encompassing the active thermal springs, were collected. Analysis of the geophysical data shows that the area is covered by low resistivity response regions at shallow depths which resulted from saline moisturized soil subsurface horizon. Relatively medium and high resistivity responses resulting from the weathered basalt, rhyolites, and ignimbrites are also mapped. Qualitative interpretation of the magnetic data shows the presence of structures that could act as pathways for heat and fluids manifesting as springs and also characterize the degree of thermal alteration of the area. Results from the investigations suggest that the Gergedi thermal springs area is controlled by fault systems oriented parallel and sub-parallel to the main tectonic lines of the Main Ethiopian Rift.

Geophysical Characterization of Groundwater-Fault Dynamics at San Andreas Oasis

NASA Astrophysics Data System (ADS)

Faherty, D.; Polet, J.; Osborn, S. G.

2017-12-01

The San Andreas Oasis has historically provided a reliable source of fresh water near the northeast margin of the Salton Sea, although since the recent completion of the Coachella Canal Lining Project and persistent drought in California, surface water at the site has begun to disappear. This may be an effect of the canal lining, however, the controls on groundwater are complicated by the presence of the Hidden Springs Fault (HSF), a northeast dipping normal fault that trends near the San Andreas Oasis. Its surface expression is apparent as a lineation against which all plant growth terminates, suggesting that it may form a partial barrier to subsurface groundwater flow. Numerous environmental studies have detailed the chemical evolution of waters resources at San Andreas Spring, although there remains a knowledge gap on the HSF and its relation to groundwater at the site. To better constrain flow paths and characterize groundwater-fault interactions, we have employed resistivity surveys near the surface trace of the HSF to generate profiles of lateral and depth-dependent variations in resistivity. The survey design is comprised of lines installed in Wenner Arrays, using an IRIS Syscal Kid, with 24 electrodes, at a maximum electrode spacing of 5 meters. In addition, we have gathered constraints on the geometry of the HSF using a combination of ground-based magnetic and gravity profiles, conducted with a GEM walking Proton Precession magnetometer and a Lacoste & Romberg gravimeter. Seventeen gravity measurements were acquired across the surface trace of the fault. Preliminary resistivity results depict a shallow conductor localized at the oasis and discontinuous across the HSF. Magnetic data reveal a large contrast in subsurface magnetic susceptibility that appears coincident with the surface trace and trend of the HSF, while gravity data suggests a shallow, relatively high density anomaly centered near the oasis. These data also hint at a second, previously

On the secular change of spring onset at Stockholm

NASA Astrophysics Data System (ADS)

Qian, Cheng; Fu, Congbin; Wu, Zhaohua; Yan, Zhongwei

2009-06-01

A newly developed method, the Ensemble Empirical Mode Decomposition, was applied to adaptively determine the timing of climatic spring onset from the daily temperature records at Stockholm during 1756-2000. Secular variations of spring onset and its relationships to the North Atlantic Oscillation (NAO) and to the temperature variability were analyzed. A clear turning point of secular trend in spring onset around 1884/1885, from delaying to advancing, was found. The delaying trend of spring onset (6.9 days/century) during 1757-1884 and the advancing one (-7 days/century) during 1885-1999 were both significant. The winter NAO indices were found to be correlated with the spring onset at Stockholm at an inter-annual timescale only for some decades, but unable to explain the change of the long-term trends. The secular change from cooling to warming around the 1880s, especially in terms of spring temperature, might have led to the secular change of spring onset.

Sensitivity of spring phenology to warming across temporal and spatial climate gradients in two independent databases

USGS Publications Warehouse

Cook, Benjamin I.; Wolkovich, Elizabeth M.; Davies, T. Jonathan; Ault, Toby R.; Betancourt, Julio L.; Allen, Jenica M.; Bolmgren, Kjell; Cleland, Elsa E.; Crimmins, Theresa M.; Kraft, Nathan J.B.; Lancaster, Lesley T.; Mazer, Susan J.; McCabe, Gregory J.; McGill, Brian J.; Parmesan, Camille; Pau, Stephanie; Regetz, James; Salamin, Nicolas; Schwartz, Mark D.; Travers, Steven E.

2012-01-01

Disparate ecological datasets are often organized into databases post hoc and then analyzed and interpreted in ways that may diverge from the purposes of the original data collections. Few studies, however, have attempted to quantify how biases inherent in these data (for example, species richness, replication, climate) affect their suitability for addressing broad scientific questions, especially in under-represented systems (for example, deserts, tropical forests) and wild communities. Here, we quantitatively compare the sensitivity of species first flowering and leafing dates to spring warmth in two phenological databases from the Northern Hemisphere. One—PEP725—has high replication within and across sites, but has low species diversity and spans a limited climate gradient. The other—NECTAR—includes many more species and a wider range of climates, but has fewer sites and low replication of species across sites. PEP725, despite low species diversity and relatively low seasonality, accurately captures the magnitude and seasonality of warming responses at climatically similar NECTAR sites, with most species showing earlier phenological events in response to warming. In NECTAR, the prevalence of temperature responders significantly declines with increasing mean annual temperature, a pattern that cannot be detected across the limited climate gradient spanned by the PEP725 flowering and leafing data. Our results showcase broad areas of agreement between the two databases, despite significant differences in species richness and geographic coverage, while also noting areas where including data across broader climate gradients may provide added value. Such comparisons help to identify gaps in our observations and knowledge base that can be addressed by ongoing monitoring and research efforts. Resolving these issues will be critical for improving predictions in understudied and under-sampled systems outside of the temperature seasonal mid-latitudes.

Sensitivity of spring phenology to warming across temporal and spatial climate gradients in two independent databases

NASA Astrophysics Data System (ADS)

Cook, B. I.; Wolkovich, E. M.; Davies, J.; Ault, T. R.; Betancourt, J. L.; Allen, J.; Bolmgren, K.; Cleland, E. E.; Crimmins, T. M.; Kraft, N.; Lancaster, L.; Mazer, S.; McCabe, G. J.; McGill, B.; Parmesan, C.; Pau, S.; Regetz, J.; Salamin, N.; Schwartz, M. D.; Travers, S.

2012-12-01

Disparate ecological datasets are often organized into databases post-hoc and then analyzed and interpreted in ways that may diverge from the purposes of the original data collections. Few studies, however, have attempted to quantify how biases inherent in these data (e.g., species richness, replication, climate) affect their suitability for addressing broad scientific questions, especially in under-represented systems (e.g., deserts, tropical forests) and wild communities. Here, we quantitatively compare the sensitivity of species first flowering and leafing dates to spring warmth in two phenological databases from the Northern Hemisphere. One—PEP725—has high replication within and across sites, but has low species diversity and spans a limited climate gradient. The other—NECTAR—includes many more species and a wider range of climates, but has fewer sites and low replication of species across sites. PEP725, despite low species diversity and relatively low seasonality, accurately captures the magnitude and seasonality of warming responses at climatically similar NECTAR sites, with most species showing earlier phenological events in response to warming. In NECTAR, the prevalence of temperature responders significantly declines with increasing mean annual temperature, a pattern that cannot be detected across the limited climate gradient spanned by the PEP725 flowering and leafing data. Our results showcase broad areas of agreement between the two databases, despite significant differences in species richness and geographic coverage, while also noting areas where including data across broader climate gradients may provide added value. Such comparisons help to identify gaps in our observations and knowledge base that can be addressed by ongoing monitoring and research efforts. Resolving these issues will be critical for improving predictions in understudied and undersampled systems outside of the temperature seasonal midlatitudes.

Plastic Faulting in Ice: Shear Localization under Elevated Pressure

NASA Astrophysics Data System (ADS)

Golding, N.; Durham, W. B.

2013-12-01

Ice exhibits, at least, two distinct kinds of shear faults when loaded triaxially under compression. Under moderate levels of confinement, brittle failure follows crack growth, crack coalescence and the development of a fault oriented about 30 degrees from the direction of maximum compression. The mechanism governing this mode of failure, termed frictional or Coulombic faulting, has previously been discussed for ice and rocks in connection with the comb-crack model. Under higher levels of confinement, where frictional sliding is suppressed by confining pressure, failure is characterized by sudden brittle-like loss in load bearing capacity and the development of a narrow shear band, comprised of recrystallized grains, oriented about 45 degrees from the direction of maximum compression, i.e. along the direction of maximum shear. This mode of failure, referred to here as plastic faulting, has previously been discussed for warm ice, T = 233 - 263 K, in connection with adiabatic shear heating and has been discussed for cold ice, T = 77 - 163 K, in connection with phase transformation. Here, new results are presented that examine the mechanical behavior and microstructural properties of plastic faulting in polycrystalline ice loaded at temperatures from T = 175 - 210 K and confining pressures up to P = 200 MPa. The results are reviewed in context of previous work and possible mechanisms to account for shear localization in ice under high pressure, including 1) adiabatic shear heating, 2) grain refinement and 3) phase transformation, are discussed. The present observations highlight the similarities in the behavior of plastic faulting under both warm and cold conditions and suggest adiabatic shear heating as a possible mechanism to account for shear instability and plastic faulting at temperatures ranging from T = 77 - 263 K.

Controlled warming effects on wheat growth and yield: field measurements and modeling

USDA-ARS?s Scientific Manuscript database

Climate warming may raise wheat yields in cooler climates and lower them in warmer. To understand these contrasting effects, infrared heating lamps were used to warm irrigated spring wheat by 1.5 'C (day) and 3.0 'C (night) above unheated controls during different times of the year at Maricopa, AZ. ...

Large springs of east Tennessee

USGS Publications Warehouse

Sun, Pao-chang P.; Criner, J.H.; Poole, J.L.

1963-01-01

Springs constitute an important source of water in east Tennessee, and many individual springs are capable of supplying the large quantities needed for municipal and industrial supplies. Most of the springs in east Tennessee issue from solution openings and fractured and faulted zones in limestone and dolomite of the Knox Group, Chickamauga Limestone, and Conasauga Group. The ability of these rocks to yield a sustained flow of water to springs is dependent on a system of interconnected openings through which water can infiltrate from the land surface and move to points of natural discharge. Ninety springs were selected for detailed study, and 84 of these are analyzed in terms of magnitude and variability of discharge. Of the 84 springs analyzed, 4 flow at an average rate of 10 to 100 cfs (cubic feet per second), 62 at an average rate of 1 to 10 cfs, and 18 at an average rate of 1 cfs or less. Of the 90 springs, 75 are variable in their discharge; that is, the ratio of their fluctuations to their average discharges exceeds 100 percent. Mathematical analysis of the flow recession curve of Mill Spring near Jefferson City shows that the hydrologic system contributing to the flow of the spring has an effective capacity of about 70 million cubic feet of water. The rate of depletion of this volume of water, in the absence of significant precipitation, averages 0.0056 cfs per day between the time when the hydrologic system is full and the time when the spring ceases to flow. From such a curve it is possible to determine at any time the residual volume of water remaining in the system and the expected rate of decrease in discharge from that time to cessation of flow. Correlation of discharge measurements of 22 springs with those of Mill Spring shows that rough approximations of discharge can be projected for springs for which few measurements are available. Seventeen of the springs analyzed in this manner show good correlation with Mill Spring: that is, their coefficients

The Confederated Tribes of the Warm Springs Indian Reservation of Oregon John Day Basin Office: FY 1999 Watershed Restoration Projects : Annual Report 1999.

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

Robertson, Shawn W.

2001-03-01

The John Day River is the second longest free-flowing river in the contiguous United States and one of the few major subbasins in the Columbia River basin containing entirely unsupplemented runs of anadromous fish. Located in eastern Oregon, the basin drains over 8,000 square miles, the fourth largest drainage area in Oregon. With its beginning in the Strawberry Mountains near the town of Prairie City, the John Day flows 284 miles in a northwesterly direction, entering the Columbia River approximately four miles upstream of the John Day dam. With wild runs of spring chinook salmon and summer steelhead, red band,more » westslope cutthroat, and redband trout, the John Day system is truly one of national significance. The entire John Day basin was granted to the Federal government in 1855 by the Confederated Tribes of the Warm Springs Reservation of Oregon (Tribes). In 1997, the Tribes established an office in the basin to coordinate restoration projects, monitoring, planning and other watershed activities on private and public lands. Once established, the John Day Basin Office (JDBO) initiated contracting the majority of its construction implementation actions with the Grant Soil and Water Conservation District (GSWCD), also located in the town of John Day. The GSWCD completes the landowner contact, preliminary planning, engineering design, permitting, construction contracting, and construction implementation phases of the projects. The JDBO completes the planning, grant solicitation/defense, environmental compliance, administrative contracting, monitoring, and reporting portion of the program. Most phases of project planning, implementation, and monitoring are coordinated with the private landowners and basin agencies, such as the Oregon Department of Fish and Wildlife and Oregon Water Resources Department. In 1999, the JDBO and GSWCD proposed continuation of a successful partnership between the two agencies and basin landowners to implement an additional eleven

Photoperiod- and Warming-driven Phenological Changes and Carbon and Nutrient Cycling. Remote Sensing Assessment

NASA Astrophysics Data System (ADS)

Penuelas, J.; Fu, Y.; Estiarte, M.; Gamon, J. A.; Filella, I.; Verger, A.; Jannssens, I.

2017-12-01

Ongoing spring warming allows the growing season to begin earlier in northern ecosystems, thus enhancing their carbon uptake. We will present data on atmospheric CO2 concentration measurements to show that this spring advancement of annual carbon intake in response to warming is decreasing. Reduced chilling during dormancy and the interactions between temperature and photoperiod in driving leaf-out may play a role. We will show that short photoperiod (in warm springs when leaf-out is early) significantly increases the heat requirement for leaf-out whereas long photoperiod (in cold springs when leaf-out is late) reduces the heat requirement for leaf-out. These two contrasting photoperiod effects illustrate a complicated temperature response of leaf-out phenology. We will also discuss how photoperiod exerts a strict control on leaf senescence at latitudes where winters are severe and temperature gains importance in the regulation as winters become less severe. On average, climatic warming will delay and drought will advance leaf senescence, but at varying degrees depending on the species. Warming and drought thus have opposite effects on the phenology of leaf senescence, and the impact of climate change will therefore depend on the relative importance of each factor in specific regions. We will then discuss the ecological effects of these phenological changes focusing, as an example, on the impacts of changes on the phenology of leaf senescence on carbon uptake and nutrient cycling. Finally, we will present recent advances on remote sensing monitoring of both the phenological changes and their ecological impacts. We will focus on advances derived from a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity.

Modification of wave-cut and faulting-controlled landforms.

USGS Publications Warehouse

Hanks, T.C.; Bucknam, R.C.; Lajoie, K.R.; Wallace, R.E.

1984-01-01

From a casual observation that the form of degraded fault scarps resembles the error function, this investigation proceeds through an elementary diffusion equation representation of landform evolution to the application of the resulting equations to the modern topography of scarplike landforms. The value of K = 1 GKG (K = 'mass diffusivity'; 1 GKG = 1m2/ka) may be generally applicable as a good first approximation, to the modification of alluvial terranes within the semiarid regions of the western United States. The Lake Bonneville shoreline K is the basis for dating four sets of fault scarps in west-central Utah. The Drum Mountains fault scarps date at 3.6 to 5.7 ka BP. Fault scarps along the eastern base of the Fish Springs Range are very young, 3 ka BP. We estimate the age of fault scarps along the western flank of the Oquirrh Mountains to be 32 ka B.P. Fault scarps along the NE margin of the Sheeprock Mountains are even older, 53 ka BP. -from Authors

Trophic level responses differ as climate warms in Ireland

NASA Astrophysics Data System (ADS)

Donnelly, Alison; Yu, Rong; Liu, Lingling

2015-08-01

Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant ( P<0.01 and P<0.001) advance in spring phenology that was driven by rising spring temperature ( P<0.05; 0.45 °C /decade). However, the rate of advance was greater for moths (1.8 days/year), followed by birds (0.37 days/year) and trees (0.29 days/year). In addition, the length of time between (1) moth emergence and leaf unfolding and (2) moth emergence and bird arrival decreased significantly ( P<0.05 and P<0.001, respectively), indicating a decrease in the timing between food supply and demand. These differing trophic level response rates demonstrate the potential for a mismatch in the timing of interdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms.

Trophic level responses differ as climate warms in Ireland.

PubMed

Donnelly, Alison; Yu, Rong; Liu, Lingling

2015-08-01

Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant (P<0.01 and P<0.001) advance in spring phenology that was driven by rising spring temperature (P<0.05; 0.45 °C /decade). However, the rate of advance was greater for moths (1.8 days/year), followed by birds (0.37 days/year) and trees (0.29 days/year). In addition, the length of time between (1) moth emergence and leaf unfolding and (2) moth emergence and bird arrival decreased significantly (P<0.05 and P<0.001, respectively), indicating a decrease in the timing between food supply and demand. These differing trophic level response rates demonstrate the potential for a mismatch in the timing of interdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms.

Transient nature of Arctic spring systems driven by subglacial meltwater

NASA Astrophysics Data System (ADS)

Scheidegger, J. M.; Bense, V. F.; Grasby, S. E.

2012-06-01

In the High Arctic, supra- and proglacial springs occur at Borup Fiord Pass, Ellesmere Island. Spring waters are sulfur bearing and isotope analysis suggests springs are fed by deeply circulating glacial meltwater. However, the mechanism maintaining spring flow is unclear in these areas of thick permafrost which would hamper the discharge of deep groundwater to the surface. It has been hypothesized that fracture zones along faults focus groundwater which discharges initially underneath wet-based parts of the ice. With thinning ice, the spring head is exposed to surface temperatures, tens of degrees lower than temperatures of pressure melting, and permafrost starts to develop. Numerical modeling of coupled heat and fluid flow suggest that focused groundwater discharge should eventually be cut off by permafrost encroaching into the feeding channel of the spring. Nevertheless, our model simulations show that these springs can remain flowing for millennia depending on the initial flow rate and ambient surface temperature. These systems might provide a terrestrial analog for the possible occurrence of Martian springs recharged by polar ice caps.

Alaska Open-File Report 127 Assessment of Thermal Springs Sites in Southern Southeastern Alaska - Preliminary Results and Evaluation

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

Motyka, Roman J.; Moorman, Mary A.; Reeder, John W.

1980-06-01

Information has been gathered on 13 reported thermal-spring sites, 12 in southern Southeastern Alaska and one in western British Columbia. Five of the reported sites could not be substantiated by DGGS. The eight known thermal spring sites are associated with grainitic terrain and, except for Baker Island Hot Springs, occur within or near intensively fractured Cretaceous-age pluons of the Coast Range Batholith. Thermal-spring surface temperatures range from 21 C (Twin Lakes) to 91.5 C (Bailey Bay). The greatest discharge occurs at Chief Shakes hot springs (450 1pm). Bell Island Hot Springs, which has about a 100-1 pm discharge and amore » 70 C temperature, has had the most development. Two previously unreported thermal-spring sites, Barnes Lake warm springs and Bradfield hot springs, have a low rate of discharge and respective surface temperatures of about 25 and 54 C. The known thermal springs probably originate from circulation of meteoric waters through deep-seated fracture and fault systems. The chemical constituents of the alkali-sulfate to alkali-chloride thermal waters are probably derived from interaction of the deeply circulating meteoric waters with the granitic wall rocks. Chemical geothermometry suggests subsurface temperatures of 55 to 151 C. If waters are being heated solely by conduction from wall rocks, circulation depths must be about 1.5 to 5 km, assuming geothermal gradients of 30 to 50 C/km. Variations in temperature, discharge, and chemistry were noted at several thermal springs for which previous records are available. A major decrease in silica and potassium concentrations at Chief Shakes hot springs is suggested by comparing recent analyses of water chemistry to Waring's (1917) original analysis. The rate of discharge at Bell Island Hot Springs may have increased by a factor of two since Waring's visit to the springs. Subsurface reservoirs associated with thermal springs in southern Southeastern Alaska are of low temperature and are

Hydrogeochemistry Characteristics and Daily Variation of Geothermal Water in the Moxi Fault,Southwest of China

NASA Astrophysics Data System (ADS)

Qi, Jihong; Xu, Mo; An, Chenjiao; Zhang, Yunhui; Zhang, Qiang

2017-04-01

The Xianshuihe Fault with frequent earthquakes activities is the regional deep fault in China. The Moxi Fault is the southern part of the Xianshuihe Fault, where the strong activities of geothermal water could bring abundant information of deep crust. In this article, some typical geothermal springs were collected along the Moxi fault from Kangding to Shimian. Using the the Na-K-Mg equilibrium diagram, it explains the state of water-rock equilibrium, and estimates the reservoir temperature basing appropriate geothermometers. Basing on the relationship between the enthalpy and chlorine concentration of geothermal water, it analyze the mixing progress of thermal water with shallow groundwater. Moreover, the responses of variation of geothermal water to the solid tides are considered to study the hydrothermal activities of this fault. The Guanding in Kangding are considered as the center of the geothermal system, and the hydrothermal activities decrease southward extending. Geothermal water maybe is heated by the deep heat source of the Himalayan granites, while the springs in the south area perform the mixture with thermal water in the sub-reservoir of the Permian crystalline limestone. It improves the research of hydrothermal activities in the Moxi Fault, meanwhile using the variation of geothermal water maybe become a important method to study the environment of deep earth in the future.

Return of warm conditions in the southeastern Bering Sea: Phytoplankton - Fish

PubMed Central

Stabeno, Phyllis J.; Siddon, Elizabeth C.; Andrews, Alex G.; Cooper, Daniel W.; Eisner, Lisa B.; Farley, Edward V.; Harpold, Colleen E.; Heintz, Ron A.; Kimmel, David G.; Sewall, Fletcher F.; Spear, Adam H.; Yasumishii, Ellen C.

2017-01-01

In 2014, the Bering Sea shifted back to warmer ocean temperatures (+2 oC above average), bringing concern for the potential for a new warm stanza and broad biological and ecological cascading effects. In 2015 and 2016 dedicated surveys were executed to study the progression of ocean heating and ecosystem response. We describe ecosystem response to multiple, consecutive years of ocean warming and offer perspective on the broader impacts. Ecosystem changes observed include reduced spring phytoplankton biomass over the southeast Bering Sea shelf relative to the north, lower abundances of large-bodied crustacean zooplankton taxa, and degraded feeding and body condition of age-0 walleye pollock. This suggests poor ecosystem conditions for young pollock production and the risk of significant decline in the number of pollock available to the pollock fishery in 2–3 years. However, we also noted that high quality prey, large copepods and euphausiids, and lower temperatures in the north may have provided a refuge from poor conditions over the southern shelf, potentially buffering the impact of a sequential-year warm stanza on the Bering Sea pollock population. We offer the hypothesis that juvenile (age-0, age-1) pollock may buffer deleterious warm stanza effects by either utilizing high productivity waters associated with the strong, northerly Cold Pool, as a refuge from the warm, low production areas of the southern shelf, or by exploiting alternative prey over the southern shelf. We show that in 2015, the ocean waters influenced by spring sea ice (the Cold Pool) supported robust phytoplankton biomass (spring) comprised of centric diatom chains, a crustacean copepod community comprised of large-bodied taxa (spring, summer), and a large aggregation of midwater fishes, potentially young pollock. In this manner, the Cold Pool may have acted as a trophic refuge in that year. The few age-0 pollock occurring over the southeast shelf consumed high numbers of euphausiids which

Return of warm conditions in the southeastern Bering Sea: Phytoplankton - Fish.

PubMed

Duffy-Anderson, Janet T; Stabeno, Phyllis J; Siddon, Elizabeth C; Andrews, Alex G; Cooper, Daniel W; Eisner, Lisa B; Farley, Edward V; Harpold, Colleen E; Heintz, Ron A; Kimmel, David G; Sewall, Fletcher F; Spear, Adam H; Yasumishii, Ellen C

2017-01-01

In 2014, the Bering Sea shifted back to warmer ocean temperatures (+2 oC above average), bringing concern for the potential for a new warm stanza and broad biological and ecological cascading effects. In 2015 and 2016 dedicated surveys were executed to study the progression of ocean heating and ecosystem response. We describe ecosystem response to multiple, consecutive years of ocean warming and offer perspective on the broader impacts. Ecosystem changes observed include reduced spring phytoplankton biomass over the southeast Bering Sea shelf relative to the north, lower abundances of large-bodied crustacean zooplankton taxa, and degraded feeding and body condition of age-0 walleye pollock. This suggests poor ecosystem conditions for young pollock production and the risk of significant decline in the number of pollock available to the pollock fishery in 2-3 years. However, we also noted that high quality prey, large copepods and euphausiids, and lower temperatures in the north may have provided a refuge from poor conditions over the southern shelf, potentially buffering the impact of a sequential-year warm stanza on the Bering Sea pollock population. We offer the hypothesis that juvenile (age-0, age-1) pollock may buffer deleterious warm stanza effects by either utilizing high productivity waters associated with the strong, northerly Cold Pool, as a refuge from the warm, low production areas of the southern shelf, or by exploiting alternative prey over the southern shelf. We show that in 2015, the ocean waters influenced by spring sea ice (the Cold Pool) supported robust phytoplankton biomass (spring) comprised of centric diatom chains, a crustacean copepod community comprised of large-bodied taxa (spring, summer), and a large aggregation of midwater fishes, potentially young pollock. In this manner, the Cold Pool may have acted as a trophic refuge in that year. The few age-0 pollock occurring over the southeast shelf consumed high numbers of euphausiids which may

Phase response curves for models of earthquake fault dynamics

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

Franović, Igor, E-mail: franovic@ipb.ac.rs; Kostić, Srdjan; Perc, Matjaž

We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how themore » profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a longer oscillation period.« less

Exceptional warming in the Western Pacific-Indian Ocean warm pool has contributed to more frequent droughts in eastern Africa

USGS Publications Warehouse

Funk, Christopher C.; Peterson, Thomas C.; Stott, Peter A.; Herring, Stephanie

2012-01-01

In 2011, East Africa faced a tragic food crisis that led to famine conditions in parts of Somalia and severe food shortages in parts of Ethiopia and Somalia. While many nonclimatic factors contributed to this crisis (high global food prices, political instability, and chronic poverty, among others) failed rains in both the boreal winter of 2010/11 and the boreal spring of 2011 played a critical role. The back-to-back failures of these rains, which were linked to the dominant La Niña climate and warm SSTs in the central and southeastern Indian Ocean, were particularly problematic since they followed poor rainfall during the spring and summer of 2008 and 2009. In fact, in parts of East Africa, in recent years, there has been a substantial increase in the number of below-normal rainy seasons, which may be related to the warming of the western Pacific and Indian Oceans (for more details, see Funk et al. 2008; Williams and Funk 2011; Williams et al. 2011; Lyon and DeWitt 2012). The basic argument of this work is that recent warming in the Indian–Pacific warm pool (IPWP) enhances the export of geopotential height energy from the warm pool, which tends to produce subsidence across eastern Africa and reduce onshore moisture transports. The general pattern of this disruption has been supported by canonical correlation analyzes and numerical experiments with the Community Atmosphere Model (Funk et al. 2008), diagnostic evaluations of reanalysis data (Williams and Funk 2011; Williams et al. 2011), and SST-driven experiments with ECHAM4.5, ECHAM5, and the Community Climate Model version 3 (CCM3.6) (Lyon and DeWitt 2012).

Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters

EPA Science Inventory

Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. We hypothesize that this warming may be amplified in the shallow (<2m), nearshore portions ...

Seasonal Variability May Affect Microbial Decomposers and Leaf Decomposition More Than Warming in Streams.

PubMed

Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia

2016-08-01

Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario.

Changes in the Onset of Spring in the Western United States

USGS Publications Warehouse

Cayan, D.R.; Kammerdiener, Susan A.; Dettinger, M.D.; Caprio, Joseph M.; Peterson, D.H.

2001-01-01

Fluctuations in spring climate in the western United States over the last 4-5 decades are described by examining changes in the blooming of plants and the timing of snowmelt-runoff pulses. The two measures of spring's onset that are employed are the timing of first bloom of lilac and honeysuckle bushes from a long-term cooperative phonological network, and the timing of the first major pulse of snowmelt recorded from high-elevation streams. Both measures contain year-to-year fluctuations, with typical year-to-year fluctuations at a given site of one to three weeks. These fluctuations are spatially coherent, forming regional patterns that cover most of the west. Fluctuations in lilac first bloom dates are highly correlated to those of honeysuckle, and both are significantly correlated with those of the spring snowmelt pulse. Each of these measures, then, probably respond to a common mechanism. Various analyses indicate that anomalous temperature exerts the greatest influence upon both interannual and secular changes in the onset of spring in these networks. Earlier spring onsets since the late 1970s are a remarkable feature of the records, and reflect the unusual spell of warmer-than-normal springs in western North America during this period. The warm episodes are clearly related to larger-scale atmospheric conditions across North America and the North Pacific, but whether this is predominantly an expression of natural variability or also a symptom of global warming is not certain.

Structural Inventory of Great Basin Geothermal Systems and Definition of Favorable Structural Settings

DOE Data Explorer

Faulds, James E.

2013-12-31

of more than 240 sites. However, we found that many “systems” consisted of little more than a warm or hot well in the central part of a basin. Such “systems” were difficult to evaluate in terms of structural setting in areas lacking in geophysical data. Developed database for structural catalogue in a master spreadsheet. Data components include structural setting, primary fault orientation, presence or absence of Quaternary faulting, reservoir lithology, geothermometry, presence or absence of recent magmatism, and distinguishing blind systems from those that have surface expressions. Reviewed site locations for all 426 geothermal systems– Confirmed and/or relocated spring and geothermal sites based on imagery, maps, and other information for master database. Many systems were mislocated in the original database. In addition, some systems that included several separate springs spread over large areas were divided into two or more distinct systems. Further, all hot wells were assigned names based on their location to facilitate subsequent analyses. We catalogued systems into the following eight major groups, based on the dominant pattern of faulting (Figure 1): - Major normal fault segments (i.e., near displacement maxima). - Fault bends. - Fault terminations or tips. - Step‐overs or relay ramps in normal faults. - Fault intersections. - Accommodation zones (i.e., belts of intermeshing oppositely dipping normal faults), - Displacement transfer zones whereby strike‐slip faults terminate in arrays of normal faults. - Transtensional pull‐aparts. These settings form a hierarchal pattern with respect to fault complexity. - Major normal faults and fault bends are the simplest. - Fault terminations are typically more complex than mid‐segments, as faults commonly break up into multiple strands or horsetail near their ends. - A fault intersection is generally more complex, as it generally contains both multiple fault strands and can include discrete di...

Fault stability under conditions of variable normal stress

USGS Publications Warehouse

Dieterich, J.H.; Linker, M.F.

1992-01-01

The stability of fault slip under conditions of varying normal stress is modelled as a spring and slider system with rate- and state-dependent friction. Coupling of normal stress to shear stress is achieved by inclining the spring at an angle, ??, to the sliding surface. Linear analysis yields two conditions for unstable slip. The first, of a type previously identified for constant normal stress systems, results in instability if stiffness is below a critical value. Critical stiffness depends on normal stress, constitutive parameters, characteristic sliding distance and the spring angle. Instability of the first type is possible only for velocity-weakening friction. The second condition yields instability if spring angle ?? <-cot-1??ss, where ??ss is steady-state sliding friction. The second condition can arise under conditions of velocity strengthening or weakening. Stability fields for finite perturbations are investigated by numerical simulation. -Authors

Urbanization may reduce the risk of frost damage to spring flowers: A case study of two shrub species in South Korea.

PubMed

Gim, Hyeon-Ju; Ho, Chang-Hoi; Kim, Jinwon; Lee, Eun Ju

2018-01-01

Regional warming, owing to urbanization, leads to earlier spring phenological events and may expose plants to hard freeze damage. This study examined the influence of urbanization on the risk of frost damage to spring flowers in South Korea from 1973 to 2015. For the analysis period, we categorized 25 cities into two groups: those showing rapid population growth (rPG) ≥ 200,000, including 13 cities, and those showing no or decreased population growth (nPG), including 12 cities. We then investigated the time from the last frost dates (LFDs) in spring to the first flowering dates (FFDs) for each group. The rPG group experienced significant spring warming of 0.47°C per decade, resulting in earlier LFDs and FFDs. For this group, the advancement of LFD was more rapid than that of FFD, and the days between these two dates increased from 0.42 to 0.47 days per decade, implying a reduced risk of frost damage. Spring warming and the advancement of FFDs and LFDs were relatively small for the nPG group, and the LFDs were rather delayed. Consequently, the days between LFDs and FFDs were reduced from -1.05 to -1.67 days per decade, indicating an increased risk of frost damage. The contrasting changes in the frost-damage risk between the two city groups can be attributed to distinct urban warming at night, which makes the LFDs substantially earlier in the rPG group. Therefore, this study suggests that the warming associated with urbanization may lessen the risk of spring frost damage to plants in rapidly growing urban areas.

Urbanization may reduce the risk of frost damage to spring flowers: A case study of two shrub species in South Korea

PubMed Central

Gim, Hyeon-Ju; Kim, Jinwon; Lee, Eun Ju

2018-01-01

Regional warming, owing to urbanization, leads to earlier spring phenological events and may expose plants to hard freeze damage. This study examined the influence of urbanization on the risk of frost damage to spring flowers in South Korea from 1973 to 2015. For the analysis period, we categorized 25 cities into two groups: those showing rapid population growth (rPG) ≥ 200,000, including 13 cities, and those showing no or decreased population growth (nPG), including 12 cities. We then investigated the time from the last frost dates (LFDs) in spring to the first flowering dates (FFDs) for each group. The rPG group experienced significant spring warming of 0.47°C per decade, resulting in earlier LFDs and FFDs. For this group, the advancement of LFD was more rapid than that of FFD, and the days between these two dates increased from 0.42 to 0.47 days per decade, implying a reduced risk of frost damage. Spring warming and the advancement of FFDs and LFDs were relatively small for the nPG group, and the LFDs were rather delayed. Consequently, the days between LFDs and FFDs were reduced from −1.05 to −1.67 days per decade, indicating an increased risk of frost damage. The contrasting changes in the frost-damage risk between the two city groups can be attributed to distinct urban warming at night, which makes the LFDs substantially earlier in the rPG group. Therefore, this study suggests that the warming associated with urbanization may lessen the risk of spring frost damage to plants in rapidly growing urban areas. PMID:29415073

Asymmetric effects of cooler and warmer winters on beech phenology last beyond spring

NASA Astrophysics Data System (ADS)

Signarbieux, Constant; Toledano, Ester; Sangines, Paula; Fu, Yongshuo; Schlaepfer, Rodolphe; Buttler, Alexandre; Vitasse, Yann

2017-04-01

In temperate trees, the timing of plant growth onset and cessation affect biogeochemical cycles, water and energy balance. Currently, phenological studies largely focus on specific phenophases and on their responses to warming. How differently spring phenology responds to the warming and cooling, and affects the subsequent phases, has not been well investigated. Here, we exposed saplings of Fagus sylvatica L. to warmer and cooler climate during the winter 2013-2014 by conducting a reciprocal transplant experiment between two elevations (1340 vs. 371 m.a.s.l., ca. 6°C difference) in the Swiss Jura mountains. To test the legacy effects of earlier or later budburst on the budset timing, saplings were moved back to their original elevation shortly after the occurrence of budburst in spring 2014. One degree decrease of air temperature resulted in a delay of 10.9 days in budburst dates, whereas one degree of warming advanced the date by 8.8 days. Interestingly, we found an asymmetric effect of the warmer winter vs. cooler winter on the budset timing in autumn: saplings experiencing a cooler winter showed a delay of 31 days in their budset timing compared to the control, whereas saplings experiencing a warmer winter showed 10 days earlier budset. The dependency of spring over autumn phenophases might be partly explained by the building up of the non-structural carbohydrate storage and suggests that the potential delay in growth cessation due to global warming might be smaller than expected. We did not find a significant correlation in budburst dates between 2014 and 2015, indicating that the legacy effects of the different phenophases might be reset during each winter. Adapting phenological models to the whole annual phenological cycle, and considering the different response to cooling and warming, would improve predictions of tree phenology under future climate warming conditions.

Growth, smoltification, and smolt-to-adult return of spring chinook salmon from hatcheries on the Deschutes river, Oregon

USGS Publications Warehouse

Beckman, B.R.; Dickhoff, Walton W.; Zaugg, W.S.; Sharpe, C.; Hirtzel, S.; Schrock, R.; Larsen, D.A.; Ewing, R.D.; Palmisano, A.; Schreck, C.B.; Mahnken, C.V.W.

1999-01-01

The relationship between smoltification and smolt-to-adult return (SAR) of spring chinook salmon Oncorhynchus tshawytscha from the Deschutes River, Oregon, was examined for four release groups in each of three successive years. Fish were reared, marked with coded wire tags, and released from Round Butte Hatchery, Pelton Ladder rearing facility, and Warm Springs National Fish Hatchery. Smolt releases occurred in nearly the same place at similar times, allowing a direct comparison of SAR to several characters representing smolt quality. Return rates varied significantly among facilities, varying over an order of magnitude each year. The highest average SAR was from Pelton Ladder, the lowest was from Warm Springs. Each of the characters used as metrics of smoltification - fish size, spring growth rate (February-April), condition factor, plasma hormone concentration (thyroxine, cortisol, and insulin-like growth factor-I [IGF-I]), stress challenge, gill Na+,K+-ATPase activity, and liver glycogen concentration - varied significantly among facilities and seasonally within hatchery groups. However, only spring growth rate, gill ATPase activity, and plasma IGF-I concentration showed significant relationships to SAR. These characters and SAR itself were consistently lower for fish released from Warm Springs Hatchery than for fish from Round Butte Hatchery and Pelton Ladder. This demonstrates that differences in the quality of fish released by facilities may have profound effects on subsequent survival and suggests that manipulations of spring growth rate may be used to influence the quality of smolts released from facilities.

Copepod community succession during warm season in Lagoon Notoro-ko, northeastern Hokkaido, Japan

NASA Astrophysics Data System (ADS)

Nakagawa, Yoshizumi; Ichikawa, Hideaki; Kitamura, Mitsuaki; Nishino, Yasuto; Taniguchi, Akira

2015-06-01

Lagoon Notoro-ko, located on the northeastern coast of Hokkaido, Japan, and connected to the Okhotsk Sea by a human-made channel, is strongly influenced by local hydrography, as water masses in the lagoon are seasonally influenced by the Soya Warm Current and the East Sakhalin Current. We here report on the succession of copepod communities during the warm season in relation to water mass exchange. Copepods were categorized into four seasonal communities (spring/early-summer, mid-summer, late-summer/fall, and early-winter) via a cluster analysis based on Bray-Curtis similarities. Spring/early-summer and early-winter communities were characterized by the temperate-boreal calanoid Pseudocalanus newmani, comprising 34.9%-77.6% of the total abundance of copepods during times of low temperature/salinity, as influenced by the prevailing East Sakhalin Current. Late-summer/fall communities were characterized by the neritic warm-water calanoid Paracalanus parvus s.l., comprising 63.9%-96.3% of the total abundance, as influenced by the Soya Warm Current. Mid-summer communities comprised approximately equal abundances of P. parvus, Eurytemora herdmani, Scolecithricella minor, and Centropages abdominalis (12.8%-28.2%); this community is transitional between those of the spring/early-summer and late-summer/fall. Copepod community succession in Lagoon Notoro-ko can be largely explained by seasonal changes in water masses.

Combined impact of climate change, cultivar shift, and sowing date on spring wheat phenology in Northern China

NASA Astrophysics Data System (ADS)

Xiao, Dengpan; Tao, Fulu; Shen, Yanjun; Qi, Yongqing

2016-08-01

Distinct climate changes since the end of the 1980s have led to clear responses in crop phenology in many parts of the world. This study investigated the trends in the dates of spring wheat phenology in relation to mean temperature for different growth stages. It also analyzed the impacts of climate change, cultivar shift, and sowing date adjustments on phenological events/phases of spring wheat in northern China (NC). The results showed that significant changes have occurred in spring wheat phenology in NC due to climate warming in the past 30 years. Specifically, the dates of anthesis and maturity of spring wheat advanced on average by 1.8 and 1.7 day (10 yr)-1. Moreover, while the vegetative growth period (VGP) shortened at most stations, the reproductive growth period (RGP) prolonged slightly at half of the investigated stations. As a result, the whole growth period (WGP) of spring wheat shortened at most stations. The findings from the Agricultural Production Systems Simulator (APSIM)-Wheat model simulated results for six representative stations further suggested that temperature rise generally shortened the spring wheat growth period in NC. Although the warming trend shortened the lengths of VGP, RGP, and WGP, the shift of new cultivars with high accumulated temperature requirements, to some extent, mitigated and adapted to the ongoing climate change. Furthermore, shifts in sowing date exerted significant impacts on the phenology of spring wheat. Generally, an advanced sowing date was able to lower the rise in mean temperature during the different growth stages (i.e., VGP, RGP, and WGP) of spring wheat. As a result, the lengths of the growth stages should be prolonged. Both measures (cultivar shift and sowing date adjustments) could be vital adaptation strategies of spring wheat to a warming climate, with potentially beneficial effects in terms of productivity.

Weakening temperature control on the interannual variations of spring carbon uptake across northern lands

NASA Astrophysics Data System (ADS)

Piao, S.; Peng, S.; Liu, Z.; Ciais, P.; Wang, T.; Huang, M.; Ahlstrom, A.; Burkhart, J. F.; Chevallier, F.; Jeong, S. J.; Janssens, I. A.; Lin, X.; Mao, J.; Myneni, R.; Shi, X.; van der Velde, I. R.; Stohl, A.; Mohammat, A.; Yao, Y.; Peñuelas, J.; Zhu, Z.; Tans, P. P.

2017-12-01

Ongoing spring warming allows the growing season to begin earlier, enhancing carbon uptake in northern ecosystems. Here we use 34 years of atmospheric CO2 concentration measurements at Barrow, Alaska (BRW, 71o N) to show that the interannual relationship between spring temperature and carbon uptake has recently shifted. We use two indicators: the spring zero-crossing date of atmospheric CO2 (SZC) and the magnitude of CO2 draw down between May and June (SCC). The previously reported strong correlation between SZC, SCC and spring land temperature (ST) was found in the first 17 years of measurements, but disappeared in the last 17 years. As a result, the sensitivity of both SZC and SCC to warming decreased. Simulations with an atmospheric transport model coupled to a terrestrial ecosystem model suggest that the weakened interannual correlation of SZC and SCC with ST in the last 17 years is attributable to the declining temperature response of spring net primary productivity (NPP) rather than to changes in heterotrophic respiration or in atmospheric transport patterns. Reduced chilling during dormancy and emerging light limitation are possible mechanisms that may have contributed to the loss of NPP response to ST. Our results thus challenge the `warmer spring-bigger sink' mechanism.

The evolving contribution of border faults and intra-rift faults in early-stage East African rifts: insights from the Natron (Tanzania) and Magadi (Kenya) basins

NASA Astrophysics Data System (ADS)

Muirhead, J.; Kattenhorn, S. A.; Dindi, E.; Gama, R.

2013-12-01

In the early stages of continental rifting, East African Rift (EAR) basins are conventionally depicted as asymmetric basins bounded on one side by a ~100 km-long border fault. As rifting progresses, strain concentrates into the rift center, producing intra-rift faults. The timing and nature of the transition from border fault to intra-rift-dominated strain accommodation is unclear. Our study focuses on this transitional phase of continental rifting by exploring the spatial and temporal evolution of faulting in the Natron (border fault initiation at ~3 Ma) and Magadi (~7 Ma) basins of northern Tanzania and southern Kenya, respectively. We compare the morphologies and activity histories of faults in each basin using field observations and remote sensing in order to address the relative contributions of border faults and intra-rift faults to crustal strain accommodation as rifting progresses. The ~500 m-high border fault along the western margin of the Natron basin is steep compared to many border faults in the eastern branch of the EAR, indicating limited scarp degradation by mass wasting. Locally, the escarpment shows open fissures and young scarps 10s of meters high and a few kilometers long, implying ongoing border fault activity in this young rift. However, intra-rift faults within ~1 Ma lavas are greatly eroded and fresh scarps are typically absent, implying long recurrence intervals between slip events. Rift-normal topographic profiles across the Natron basin show the lowest elevations in the lake-filled basin adjacent to the border fault, where a number of hydrothermal springs along the border fault system expel water into the lake. In contrast to Natron, a ~1600 m high, densely vegetated, border fault escarpment along the western edge of the Magadi basin is highly degraded; we were unable to identify evidence of recent rupturing. Rift-normal elevation profiles indicate the focus of strain has migrated away from the border fault into the rift center, where

Phenology of lilac (Syringa vulgaris) and elderberry (Sambucus nigra) as the indicator of spring warming

NASA Astrophysics Data System (ADS)

Vincze, E.; Hunkár, M.; Dunkel, Z.

2012-04-01

Phenological observations in Hungary started in 1871. The observation system collapsed and revived time by time. The aim of the observations as well as the locations, the methods and observed plants have been changed many times, therefore data series for a given plant species derived from the same place are rare. If we want to study the responses of biosphere to climate variability we need long time data series from the same places, especially phenological data of native plants. Phenological observations organized by the Hungarian Meteorological Service between 1983- 1999 contain valuable data for lilac (Syringa vulgaris) and elderberry (Sambucus nigra). Those perennial native plants are good indicators of spring warming therefore it is worth to study their phenological development concerning to climate variability. Eight locations in Hungary were selected where the site of the observations remaind the same year by year. Observed phenological phases were: Sprouting of leaves (SL, BBCH:11); Begin of Flowers (BF, BBCH:61); Fall of leaves (FO, BBCH:95). Spatial and temporal trends and variability of phenophases will be presented. The effect of meteorological conditions is studied to build up phenological model controlled by the temperature. Growing degree days above the base temperature was involved together with the duration and severeness of the chilling period. The study is supported by the National Scientific Foundation (OTKA-81979).

Sample Return from Ancient Hydrothermal Springs

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy Z.

2008-01-01

Hydrothermal spring deposits on Mars would make excellent candidates for sample return. Molecular phylogeny suggests that that life on Earth may have arisen in hydrothermal settings [1-3], and on Mars, such settings not only would have supplied energy-rich waters in which martian life may have evolved [4-7] but also would have provided warm, liquid water to martian life forms as the climate became colder and drier [8]. Since silica, sulfates, and clays associated with hydrothermal settings are known to preserve geochemical and morphological remains of ancient terrestrial life [9-11], such settings on Mars might similarly preserve evidence of martian life. Finally, because formation of hydrothermal springs includes surface and subsurface processes, martian spring deposits would offer the potential to assess astrobiological potential and hydrological history in a variety of settings, including surface mineralized terraces, associated stream deposits, and subsurface environments where organic remains may have been well protected from oxidation. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data [12-14]. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel, and based on these new data, we have interpreted several features in Vernal Crater, Arabia Terra as ancient hydrothermal springs [15, 16].

A fault-based model for crustal deformation, fault slip-rates and off-fault strain rate in California

USGS Publications Warehouse

Zeng, Yuehua; Shen, Zheng-Kang

2016-01-01

We invert Global Positioning System (GPS) velocity data to estimate fault slip rates in California using a fault‐based crustal deformation model with geologic constraints. The model assumes buried elastic dislocations across the region using Uniform California Earthquake Rupture Forecast Version 3 (UCERF3) fault geometries. New GPS velocity and geologic slip‐rate data were compiled by the UCERF3 deformation working group. The result of least‐squares inversion shows that the San Andreas fault slips at 19–22  mm/yr along Santa Cruz to the North Coast, 25–28  mm/yr along the central California creeping segment to the Carrizo Plain, 20–22  mm/yr along the Mojave, and 20–24  mm/yr along the Coachella to the Imperial Valley. Modeled slip rates are 7–16  mm/yr lower than the preferred geologic rates from the central California creeping section to the San Bernardino North section. For the Bartlett Springs section, fault slip rates of 7–9  mm/yr fall within the geologic bounds but are twice the preferred geologic rates. For the central and eastern Garlock, inverted slip rates of 7.5 and 4.9  mm/yr, respectively, match closely with the geologic rates. For the western Garlock, however, our result suggests a low slip rate of 1.7  mm/yr. Along the eastern California shear zone and southern Walker Lane, our model shows a cumulative slip rate of 6.2–6.9  mm/yr across its east–west transects, which is ∼1  mm/yr increase of the geologic estimates. For the off‐coast faults of central California, from Hosgri to San Gregorio, fault slips are modeled at 1–5  mm/yr, similar to the lower geologic bounds. For the off‐fault deformation, the total moment rate amounts to 0.88×1019  N·m/yr, with fast straining regions found around the Mendocino triple junction, Transverse Ranges and Garlock fault zones, Landers and Brawley seismic zones, and farther south. The overall California moment rate is 2.76×1019�

Performance and application of a fluidized bed limestone reactor designed for control of alkalinity, hardness and pH at the Warm Springs Regional Fisheries Center

USGS Publications Warehouse

Watten, Barnaby J.; Mudrak, Vincent A.; Echevarria, Carlos; Sibrell, Philip; Summerfelt, Steven T.; Boyd, Claude E.

2017-01-01

Springs serving the Warm Springs Regional Fisheries Center, Warm Springs, Georgia, have pH, alkalinity, and hardness levels thatlie under the range required for successful fish propagation while free CO2 is well above allowable targets. We evaluate a pretreatment process that exploits limestone’s (CaCO3) ability to react away hydrogen ions (H+) and carbon dioxide (CO2) while increasing alkalinity (HCO3−) and calcium (Ca2+) concentrations, i.e. CaCO3 + H+ ↔ HCO3− + Ca2+ CaCO3 + CO2 + H2O ↔ Ca2+ + 2HCO3− Limestone sand was tested in both pilot and full scale fluidized bed reactors (CycloBio®). We first established the bed expansion characteristics of three commercial limestone products then evaluated the effect of hydraulic flux and bed height on dissolution rate of a single selected product (Type A16 × 120). Pilot scale testing at 18C showed limestone dissolution rates were relatively insensitive to flux over the range 1.51–3.03 m3/min/m2 but were sensitive (P < 0.001; R2 = 0.881) to changes in bed height (BH, cm) over the range 83–165 cm following the relation: (Alkalinity, mg/L) = 123.51 − (3788.76 (BH)). Differences between filtered and non-filtered alkalinity were small(P > 0.05) demonstrating that limestone was present in the reactor effluent primarily in the form of dissolved Ca(HCO3)2. Effluent alkalinity exceeded our target level of 50 mg/L under most operating conditions evaluated with typical pilot scale values falling within the range of 90–100 mg/L despite influent concentrations of about 4 mg/L. Concurrently, CO2 fell from an average of 50.6 mg/L to 8.3 mg/L (90%), providing for an increase in pH from 5.27 to a mean of 7.71. The ability of the test reactor to provide changes in water chemistry variables that exceeded required changes allowed for a dilution ratio of 0.6. Here, alkalinity still exceeded 50 mg/L, the CO2 concentration remained well below our limit of 20 mg/L (15.4 mg/L) and the pH was near neutral (7.17). Applying the

Incremental Holocene slip rates from the Hope fault at Hossack Station, Marlborough fault zone, South Island, New Zealand

NASA Astrophysics Data System (ADS)

Hatem, A. E.; Dolan, J. F.; Langridge, R.; Zinke, R. W.; McGuire, C. P.; Rhodes, E. J.; Van Dissen, R. J.

2015-12-01

The Marlborough fault system, which links the Alpine fault with the Hikurangi subduction zone within the complex Australian-Pacific plate boundary zone, partitions strain between the Wairau, Awatere, Clarence and Hope faults. Previous best estimates of dextral strike-slip along the Hope fault are ≤ ~23 mm/yr± 4 mm/year. Those rates, however, are poorly constrained and could be improved using better age determinations in conjunction with measurements of fault offsets using high-resolution imagery. In this study, we use airborne lidar- and field-based mapping together with the subsurface geometry of offset channels at the Hossack site 12 km ESE of Hanmer Springs to more precisely determine stream offsets that were previously identified by McMorran (1991). Specifically, we measured fault offsets of ~10m, ~75 m, and ~195m. Together with 65 radiocarbon ages on charcoal, peat, and wood and 25 pending post-IR50-IRSL225 luminescence ages from the channel deposits, these offsets yield three different fault slip rates for the early Holocene, the late Holocene, and the past ca. 500-1,000 years. Using the large number of age determinations, we document in detail the timing of initiation and abandonment of each channel, enhancing the geomorphic interpretation at the Hossack site as channels deform over many earthquake cycles. Our preliminary incremental slip rate results from the Hossack site may indicate temporally variable strain release along the Hope fault. This study is part of a broader effort aimed at determining incremental slip rates and paleo-earthquake ages and displacements from all four main Marlborough faults. Collectively, these data will allow us to determine how the four main Marlborough faults have work together during Holocene-late Pleistocene to accommodate plate-boundary deformation in time and space.

The Tropical Western Hemisphere Warm Pool

NASA Astrophysics Data System (ADS)

Wang, C.; Enfield, D. B.

2002-12-01

The paper describes and examines variability of the tropical Western Hemisphere warm pool (WHWP) of water warmer than 28.5oC. The WHWP is the second-largest tropical warm pool on Earth. Unlike the Eastern Hemisphere warm pool in the western Pacific, which straddles the equator, the WHWP is entirely north of the equator. At various stages of development the WHWP extends over parts of the eastern North Pacific, the Gulf of Mexico, the Caribbean, and the western tropical North Atlantic. It has a large seasonal cycle and its interannual fluctuations of area and intensity are significant. Surface heat fluxes warm the WHWP through the boreal spring to an annual maximum of SST and WHWP area in the late summer/early fall, associated with eastern North Pacific and Atlantic hurricane activities and rainfall from northern South America to the southern tier of the United States. Observations suggest that a positive ocean-atmosphere feedback operating through longwave radiation and associated cloudiness seems to operate in the WHWP. During winter preceding large warm pool, there is an alteration of the Walker and Hadley circulation cells that serves as a "tropospheric bridge" for transferring Pacific ENSO effects to the Atlantic sector and inducing initial warming of warm pool. Associated with the warm SST anomalies is a decrease in sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less net longwave radiation loss from the sea surface, which then reinforces SST anomalies.

Temperature alone does not explain phenological variation of diverse temperate plants under experimental warming.

PubMed

Marchin, Renée M; Salk, Carl F; Hoffmann, William A; Dunn, Robert R

2015-08-01

Anthropogenic climate change has altered temperate forest phenology, but how these trends will play out in the future is controversial. We measured the effect of experimental warming of 0.6-5.0 °C on the phenology of a diverse suite of 11 plant species in the deciduous forest understory (Duke Forest, North Carolina, USA) in a relatively warm year (2011) and a colder year (2013). Our primary goal was to dissect how temperature affects timing of spring budburst, flowering, and autumn leaf coloring for functional groups with different growth habits, phenological niches, and xylem anatomy. Warming advanced budburst of six deciduous woody species by 5-15 days and delayed leaf coloring by 18-21 days, resulting in an extension of the growing season by as much as 20-29 days. Spring temperature accumulation was strongly correlated with budburst date, but temperature alone cannot explain the diverse budburst responses observed among plant functional types. Ring-porous trees showed a consistent temperature response pattern across years, suggesting these species are sensitive to photoperiod. Conversely, diffuse-porous species responded differently between years, suggesting winter chilling may be more important in regulating budburst. Budburst of the ring-porous Quercus alba responded nonlinearly to warming, suggesting evolutionary constraints may limit changes in phenology, and therefore productivity, in the future. Warming caused a divergence in flowering times among species in the forest community, resulting in a longer flowering season by 10-16 days. Temperature was a good predictor of flowering for only four of the seven species studied here. Observations of interannual temperature variability overpredicted flowering responses in spring-blooming species, relative to our warming experiment, and did not consistently predict even the direction of flowering shifts. Experiments that push temperatures beyond historic variation are indispensable for improving predictions of

Fault Slip Partitioning in the Eastern California Shear Zone-Walker Lane Belt: Pliocene to Late Pleistocene Contraction Across the Mina Deflection

NASA Astrophysics Data System (ADS)

Lee, J.; Stockli, D.; Gosse, J.

2007-12-01

Two different mechanisms have been proposed for fault slip transfer between the subparallel NW-striking dextral- slip faults that dominant the Eastern California Shear Zone (ECSZ)-Walker Lane Belt (WLB). In the northern WLB, domains of sinistral-slip along NE-striking faults and clockwise block rotation within a zone of distributed deformation accommodated NW-dextral shear. A somewhat modified version of this mechanism was also proposed for the Mina deflection, southern WLB, whereby NE-striking sinistral faults formed as conjugate faults to the primary zone of NW-dextral shear; clockwise rotation of the blocks bounding the sinistral faults accommodated dextral slip. In contrast, in the northern ECSZ and Mina deflection, domains of NE-striking pure dip-slip normal faults, bounded by NW-striking dextral-slip faults, exhibited no rotation; the proposed mechanism of slip transfer was one of right-stepping, high angle normal faults in which the magnitude of extension was proportional to the amount of strike-slip motion transferred. New geologic mapping, tectonic geomorphologic, and geochronologic data from the Queen Valley area, southern Mina deflection constrain Pliocene to late Quaternary fault geometries, slip orientations, slip magnitudes, and slip rates that bear on the mechanism of fault slip transfer from the relatively narrow northern ECSZ to the broad deformation zone that defines the Mina deflection. Four different fault types and orientations cut across the Queen Valley area: (1) The NE-striking normal-slip Queen Valley fault; (2) NE-striking sinistral faults; (3) the NW-striking dextral Coyote Springs fault, which merges into (4) a set of EW-striking thrust faults. (U-Th)/He apatite and cosmogenic radionuclide data, combined with magnitude of fault offset measurements, indicate a Pliocene to late Pleistocene horizontal extension rate of 0.2-0.3 mm/yr across the Queen Valley fault. Our results, combined with published slip rates for the dextral White Mountain

Weakening temperature control on the interannual variations of spring carbon uptake across northern lands

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

Piao, Shilong; Liu, Zhuo; Wang, Tao

2017-04-24

Ongoing spring warming allows the growing season to begin earlier, enhancing carbon uptake in northern ecosystems. We use 34 years of atmospheric CO 2 concentration measurements at Barrow, Alaska (BRW, 71° N) to show that the interannual relationship between spring temperature and carbon uptake has recently shifted. Here, we use two indicators: the spring zero-crossing date of atmospheric CO 2 (SZC) and the magnitude of CO 2 drawdown between May and June (SCC). The previously reported strong correlation between SZC, SCC and spring land temperature (ST) was found in the first 17 years of measurements, but disappeared in the lastmore » 17 years. As a result, the sensitivity of both SZC and SCC to warming decreased. Simulations with an atmospheric transport model coupled to a terrestrial ecosystem model suggest that the weakened interannual correlation of SZC and SCC with ST in the last 17 years is attributable to the declining temperature response of spring net primary productivity (NPP) rather than to changes in heterotrophic respiration or in atmospheric transport patterns. Reduced chilling during dormancy and emerging light limitation are possible mechanisms that may have contributed to the loss of NPP response to ST. These results thus challenge the ‘warmer spring–bigger sink’ mechanism.« less

Potential for an Arctic-breeding migratory bird to adjust spring migration phenology to Arctic amplification.

PubMed

Lameris, Thomas K; Scholten, Ilse; Bauer, Silke; Cobben, Marleen M P; Ens, Bruno J; Nolet, Bart A

2017-10-01

Arctic amplification, the accelerated climate warming in the polar regions, is causing a more rapid advancement of the onset of spring in the Arctic than in temperate regions. Consequently, the arrival of many migratory birds in the Arctic is thought to become increasingly mismatched with the onset of local spring, consequently reducing individual fitness and potentially even population levels. We used a dynamic state variable model to study whether Arctic long-distance migrants can advance their migratory schedules under climate warming scenarios which include Arctic amplification, and whether such an advancement is constrained by fuel accumulation or the ability to anticipate climatic changes. Our model predicts that barnacle geese Branta leucopsis suffer from considerably reduced reproductive success with increasing Arctic amplification through mistimed arrival, when they cannot anticipate a more rapid progress of Arctic spring from their wintering grounds. When geese are able to anticipate a more rapid progress of Arctic spring, they are predicted to advance their spring arrival under Arctic amplification up to 44 days without any reproductive costs in terms of optimal condition or timing of breeding. Negative effects of mistimed arrival on reproduction are predicted to be somewhat mitigated by increasing summer length under warming in the Arctic, as late arriving geese can still breed successfully. We conclude that adaptation to Arctic amplification may rather be constrained by the (un)predictability of changes in the Arctic spring than by the time available for fuel accumulation. Social migrants like geese tend to have a high behavioural plasticity regarding stopover site choice and migration schedule, giving them the potential to adapt to future climate changes on their flyway. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

The origin of life in geothermal hot springs: Darwin's warm little pond revisited

NASA Astrophysics Data System (ADS)

Deamer, D.

2016-12-01

The origin of life in geothermal hot springs: Darwin's warm little pond revisited David Deamer and Bruce Damer, Department of Biomolecular Engineering, University of California, Santa Cruz CA 95064 We are exploring ways in which mononucleotides can undergo polymerization and encapsulation in the presence of an organizing matrix (1, 2, 3). When mixtures of amphiphilic lipids and mononucleotides are exposed to cycles of dehydration and rehydration, the lipids concentrate and organize the monomers within multilamellar liquid-crystalline matrices that self-assemble in the dry state. The chemical potential driving the polymerization reaction is supplied by the anhydrous conditions in which water becomes a leaving group, with heat providing activation energy. Upon rehydration, the polymeric products are encapsulated in trillions of microscopic compartments. Each compartment is unique in its composition and contents, and can be considered to be an experiment in a natural version of combinatorial chemistry that would be ubiquitous in the prebiotic environment. There are specific thermodynamic and kinetic considerations required for this process to work which are related to cycles of evaporation and rehydration, ionic composition, salt concentration, pH and temperature. These conditions are present in hydrothermal fields associated with volcanic activity on today's Earth and can be compared with the range of possible conditions on Enceladus to estimate the probability that life can emerge on an icy world with a subsurface salty liquid ocean. 1. De Guzman V, Shenasa H, Vercoutere W, Deamer D (2014) Generation of oligonucleotides under hydrothermal conditions by non-enzymatic polymerization. J Mol Evol 78:251-262 2. Deamer D. 2012. Liquid crystalline nanostructures: organizing matrices for non-enzymatic nucleic acid polymerization. Chem Soc Rev. 41:5375-9. 3. Damer B, Deamer D. 2015. Coupled phases and combinatorial selection in fluctuating hydrothermal pools: a scenario to

Late Cenozoic strike-slip faulting in the NE Mojave Block: Deformation at the southwest boundary of the Walker Lane belt

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

Schermer, E.R.

1993-04-01

New structural and stratigraphy data from the NE Mojave Block (NEMB) establish the timing and style of Cenozoic deformation south of the Garlock fault and west of the Avawatz Mts. Unlike adjacent areas, most of the NEMB did not undergo early-mid Miocene extension. Major fault zones strike EW; offset markers and small-scale shear criteria indicate left-lateral strike slip with a small reverse component. Lateral offsets average ca. 1--6 km and vertical offset is locally >200m. Pre-Tertiary markers indicate minimum cumulative sinistral shear of ca. 15 km in the area between the Garlock and Coyote Lake faults. Tertiary strata are deformedmore » together with the older rocks. Along the Ft. Irwin fault, alluvial fan deposits interpreted to be <11Ma appear to be displaced as much as Mesozoic igneous rocks. EW sinistral faults S. of the Garlock fault cut unconsolidated Quaternary deposits; geomorphologic features and trench exposures along segments of the McLean Lake fault and the Tiefort Mt. fault suggest Late Quaternary activity. The EW faults do not cut modern drainages and are not seismically active. NW-striking faults are largely absent within the NEMB; the largest faults bound the domain of EW-striking faults. Offset of Cretaceous and Miocene rocks suggests the W boundary (Goldstone Lake fault) has <2km right separation. Along the E boundary (Soda-Avawatz fault zone), the presence of distinctive clasts in mid-late Miocene conglomerates west of the Avawatz Mts. supports the suggestion of Brady (1984) of ca. 20 km dextral displacement. Other NW-striking faults are cut by EW faults, have unknown or minor dextral displacement (Desert King Spring Fault, Garlic Spring fault) or are low- to moderate-angle left-oblique thrust faults (Red Pass Lake fault zone).« less

Effect of warming temperatures on US wheat yields.

PubMed

Tack, Jesse; Barkley, Andrew; Nalley, Lawton Lanier

2015-06-02

Climate change is expected to increase future temperatures, potentially resulting in reduced crop production in many key production regions. Research quantifying the complex relationship between weather variables and wheat yields is rapidly growing, and recent advances have used a variety of model specifications that differ in how temperature data are included in the statistical yield equation. A unique data set that combines Kansas wheat variety field trial outcomes for 1985-2013 with location-specific weather data is used to analyze the effect of weather on wheat yield using regression analysis. Our results indicate that the effect of temperature exposure varies across the September-May growing season. The largest drivers of yield loss are freezing temperatures in the Fall and extreme heat events in the Spring. We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures. Our analysis indicates that there exists a tradeoff between average (mean) yield and ability to resist extreme heat across varieties. More-recently released varieties are less able to resist heat than older lines. Our results also indicate that warming effects would be partially offset by increased rainfall in the Spring. Finally, we find that the method used to construct measures of temperature exposure matters for both the predictive performance of the regression model and the forecasted warming impacts on yields.

Near-Surface Geophysical Character of a Holocene Fault Carrying Geothermal Flow Near Pyramid Lake, Nevada

NASA Astrophysics Data System (ADS)

Dudley, C.; Dorsey, A.; Louie, J. N.; Schwering, P. C.; Pullammanappallil, S.

2012-12-01

Lines of calcium carbonate tufa columns mark recent faults that cut 11 ka Lake Lahontan sediments at Astor Pass, north of Pyramid Lake, Nevada. Throughout the Great Basin, faults appear to control the location of geothermal resources, providing pathways for fluid migration. Reservoir-depth (greater than 1 km) seismic imaging at Astor Pass shows a fault that projects to one of the lines of tufa columns at the surface. The presence of the tufa deposits suggests this fault carried warm geothermal waters through the lakebed clay sediments in recent time. The warm fluids deposited the tufa when they hit cold Lake Lahontan water at the lakebed. Lake Lahontan covered this location to a depth of at least 60 m at 11 ka. In collaboration with the Pyramid Lake Paiute Tribe, an Applied Geophysics class at UNR investigated the near-surface geophysical characteristics of this fault. The survey comprises near-surface seismic reflection and refraction, nine near-surface refraction microtremor (SeisOpt® ReMi™) arrays, nine near-surface direct-current resistivity soundings, magnetic surveys, and gravity surveys at and near the tufa columns. The refraction microtremor results show shear velocities near tufa and faults to be marginally lower, compared to Vs away from the faults. Overall, the 30-m depth-averaged shear velocities are low, less than 300 m/s, consistent with the lakebed clay deposits. These results show no indication of any fast (> 500 m/s) tufa below the surface at or near the tufa columns. Vs30 averages were 274 ± 13 m/s on the fault, 287 ± 2 m/s at 150 m east of the fault, and 290 ± 15 m/s at 150 m west of the fault. The P-velocity refraction optimization results also show no indication of high-velocity tufa buried below the surface in the Lahontan sediments, reinforcing the idea that all tufa was deposited above the lakebed surface. The seismic results provide a negative test of the hypothesis that deposition of the lakebeds in the Quaternary buried and

Fault-controlled CO2 leakage from natural reservoirs in the Colorado Plateau, East-Central Utah

NASA Astrophysics Data System (ADS)

Jung, Na-Hyun; Han, Weon Shik; Watson, Z. T.; Graham, Jack P.; Kim, Kue-Young

2014-10-01

The study investigated a natural analogue for soil CO2 fluxes where CO2 has naturally leaked on the Colorado Plateau, East-Central Utah in order to identify various factors that control CO2 leakage and to understand regional-scale CO2 leakage processes in fault systems. The total 332 and 140 measurements of soil CO2 flux were made at 287 and 129 sites in the Little Grand Wash (LGW) and Salt Wash (SW) fault zones, respectively. Measurement sites for CO2 flux involved not only conspicuous CO2 degassing features (e.g., CO2-driven springs/geysers) but also linear features (e.g., joints/fractures and areas of diffusive leakage around a fault damage zone). CO2 flux anomalies were mostly observed along the fault traces. Specifically, CO2 flux anomalies were focused in the northern footwall of the both LGW and SW faults, supporting the existence of north-plunging anticlinal CO2 trap against south-dipping faults as well as higher probability of the north major fault traces as conduits. Anomalous CO2 fluxes also appeared in active travertines adjacent to CO2-driven cold springs and geysers (e.g., 36,259 g m-2 d-1 at Crystal Geyser), ancient travertines (e.g., 5,917 g m-2 d-1), joint zones in sandstone (e.g., 120 g m-2 d-1), and brine discharge zones (e.g., 5,515 g m-2 d-1). These observations indicate that CO2 has escaped through those pathways and that CO2 leakage from these fault zones does not correspond to point source leakage. The magnitude of CO2 flux is progressively reduced from north (i.e. the LGW fault zone, ∼36,259 g m-2 d-1) to south (i.e. the SW fault zone, ∼1,428 g m-2 d-1) despite new inputs of CO2 and CO2-saturated brine to the northerly SW fault from depth. This discrepancy in CO2 flux is most likely resulting from the differences in fault zone architecture and associated permeability structure. CO2-rich fluids from the LGW fault zone may become depleted with respect to CO2 during lateral transport, resulting in an additional decrease in CO2 fluxes

Automatic fault tracing of active faults in the Sutlej valley (NW-Himalayas, India)

NASA Astrophysics Data System (ADS)

Janda, C.; Faber, R.; Hager, C.; Grasemann, B.

2003-04-01

In the Sutlej Valley the Lesser Himalayan Crystalline Sequence (LHCS) is actively extruding between the Munsiari Thrust (MT) at the base, and the Karcham Normal Fault (KNF) at the top. The clear evidences for ongoing deformation are brittle faults in Holocene lake deposits, hot springs activity near the faults and dramatically younger cooling ages within the LHCS (Vannay and Grasemann, 2001). Because these brittle fault zones obviously influence the morphology in the field we developed a new method for automatically tracing the intersections of planar fault geometries with digital elevation models (Faber, 2002). Traditional mapping techniques use structure contours (i.e. lines or curves connecting points of equal elevation on a geological structure) in order to construct intersections of geological structures with topographic maps. However, even if the geological structure is approximated by a plane and therefore structure contours are equally spaced lines, this technique is rather time consuming and inaccurate, because errors are cumulative. Drawing structure contours by hand makes it also impossible to slightly change the azimuth and dip direction of the favoured plane without redrawing everything from the beginning on. However, small variations of the fault position which are easily possible by either inaccuracies of measurement in the field or small local variations in the trend and/or dip of the fault planes can have big effects on the intersection with topography. The developed method allows to interactively view intersections in a 2D and 3D mode. Unlimited numbers of planes can be moved separately in 3 dimensions (translation and rotation) and intersections with the topography probably following morphological features can be mapped. Besides the increase of efficiency this method underlines the shortcoming of classical lineament extraction ignoring the dip of planar structures. Using this method, areas of active faulting influencing the morphology, can be

CMIP5 projected changes in spring and summer drought and wet conditions over North America

NASA Astrophysics Data System (ADS)

Swain, Sharmistha; Hayhoe, Katharine

2015-05-01

Climate change is expected to alter the mean and variability of future spring and summer drought and wet conditions during the twenty-first century across North America, as characterized by the Standardized Precipitation Index (SPI). Based on Coupled Model Intercomparison Project phase 5 simulations, statistically significant increases are projected in mean spring SPI over the northern part of the continent, and drier conditions across the southwest. Dry conditions in summer also increase, particularly throughout the central Great Plains. By end of century, greater changes are projected under a higher radiative forcing scenario (RCP 8.5) as compared to moderate (RCP 6.0) and lower (RCP 4.5). Analysis of projected changes standardized to a range of global warming thresholds from +1 to +4 °C reveals a consistent spatial pattern of wetter conditions in the northern and drier conditions in the southwestern part of the continent in spring that intensifies under increased warming, suggesting that the magnitude of projected changes in wetness and drought may scale with global temperature. For many regions, SPI interannual variability is also projected to increase (even for regions that are projected to become drier), indicating that climate may become more extreme under greater warming, with increased frequency of both extreme dry and wet seasons. Quantifying the direction and magnitude of projected future trends from global warming is key to informing strategies to mitigate human influence on climate and help natural and managed resources adapt.

A case for ancient springs in Arabia Terra, Mars.

PubMed

Allen, Carlton C; Oehler, Dorothy Z

2008-12-01

Based on new image data from the High Resolution Imaging Science Experiment (HiRISE) on Mars Reconnaissance Orbiter (MRO), a case can be made that several structures in Vernal Crater, Arabia Terra are ancient springs. This interpretation is based on comprehensive geomorphologic analysis coupled with assessment of multiple hypotheses. The structures identified extend across several kilometers and are exceptional in that nothing with their detail and scale has been reported from Mars. The deposits are associated with an extensive fracture system that may have facilitated upward flow of warm fluids. Several additional spring-like features occur in Vernal Crater, and it is possible that these are part of a major province of spring activity. Since springs are environments where life could have evolved on Mars, where that life could have found refuge as the climate became colder and drier, and where signatures of that life may be preserved, Vernal Crater may be a site of major astrobiological importance.

[Effects of sowing times on the spike differentiation of different wheat varieties under the climate of warm winter].

PubMed

Gao, Qinglu; Xue, Xiang; Wu, Yu; Ru, Zhengang

2003-10-01

Spike differentiation processes and freezing damage of three wheat varieties were studied by sowing in different stages. The results showed that under the condition of weather changing warm, the time of entering each stage of spike differentiation of wheat of strong spring variety was earlier than that of wheat of spring variety and semi-winter variety. Sowing times had more effects on durative time of the elongation stage, single-prism stage and two-prism stage of the spike differentiation. Under sowing early, the stronger the springness of wheat was, the quicker it developed, the higher spike differentiation phases it reached before winter, and the more serious freezing damage it suffered in wintering. According to this, the semi-winter varieties of wheat should be adopted first and arranged in pairs with spring varieties in wheat production, and the sowing times should not be too early as the weather becoming warm.

Earthquake geology and paleoseismology of major strands of the San Andreas fault system: Chapter 38

USGS Publications Warehouse

Rockwell, Thomas; Scharer, Katherine M.; Dawson, Timothy E.

2016-01-01

The San Andreas fault system in California is one of the best-studied faults in the world, both in terms of the long-term geologic history and paleoseismic study of past surface ruptures. In this paper, we focus on the Quaternary to historic data that have been collected from the major strands of the San Andreas fault system, both on the San Andreas Fault itself, and the major subparallel strands that comprise the plate boundary, including the Calaveras-Hayward- Rogers Creek-Maacama fault zone and the Concord-Green Valley-Bartlett Springs fault zone in northern California, and the San Jacinto and Elsinore faults in southern California. The majority of the relative motion between the Pacific and North American lithospheric plates is accommodated by these faults, with the San Andreas slipping at about 34 mm/yr in central California, decreasing to about 20 mm/yr in northern California north of its juncture with the Calaveras and Concord faults. The Calaveras-Hayward-Rogers Creek-Maacama fault zone exhibits a slip rate of 10-15 mm/yr, whereas the rate along the Concord-Green Valley-Bartlett Springs fault zone is lower at about 5 mm/yr. In southern California, the San Andreas exhibits a slip rate of about 35 mm/yr along the Mojave section, decreasing to as low as 10-15 mm/yr along its juncture with the San Jacinto fault, and about 20 mm/yr in the Coachella Valley. The San Jacinto and Elsinore fault zones exhibit rates of about 15 and 5 mm/yr, respectively. The average recurrence interval for surface-rupturing earthquakes along individual elements of the San Andreas fault system range from 100-500 years and is consistent with slip rate at those sites: higher slip rates produce more frequent or larger earthquakes. There is also evidence of short-term variations in strain release (slip rate) along various fault sections, as expressed as “flurries” or clusters of earthquakes as well as periods of relatively fewer surface ruptures in these relatively short records. This

Effects of extreme spring temperatures on phenology: a case study from Munich and Ingolstadt

NASA Astrophysics Data System (ADS)

Jochner, Susanne; Menzel, Annette

2010-05-01

Extreme events - e.g. warm spells or heavy precipitation events - are likely to increase in the future both in frequency and intensity. Therefore, research on extreme events gains new importance; also in terms of plant development which is mostly triggered by temperatures. An arising question is how plants respond to an extreme warm spell when following an extreme cold winter season. This situation could be studied in spring 2009 in the greater area of Munich and Ingolstadt by phenological observations of flowering and leaf unfolding of birch (Betula pendula L.) and flowering of horse chestnut (Aesculus hippocastanum L.). The long chilling period of winter 2008 and spring 2009 was followed by an immediate strong forcing of flowering and leaf unfolding, especially for birch. This extreme weather situation diminished the difference between urban and rural dates of onset. Another important fact that could be observed in the proceeding period of December 2008 to April 2009 was the reduced temperature difference among urban and rural sites (urban heat island effect). Long-term observations (1951-2008) of the phenological network of the German Meteorological Service (DWD) were used to identify years with reduced urban-rural differences between onset times in the greater area of Munich in the past. Statistical analyses were conducted in order to answer the question whether the sequence of extreme warm and cold events leads to a decreased difference in phenological onset times or if this behaviour can be attributed to extreme warm springs themselves or to the decreased urban heat island effect which is mostly affected by general atmospheric circulation patterns.

Geologic map of the Bateman Spring Quadrangle, Lander County, Nevada

USGS Publications Warehouse

Ramelli, Alan R.; Wrucke, Chester T.; House, P. Kyle

2017-01-01

This 1:24,000-scale geologic map of the Bateman Spring 7.5-minute quadrangle in Lander County, Nevada contains descriptions of 24 geologic units and one cross section. Accompanying text includes full unit descriptions and references. This quadrangle includes lower Paleozoic siliciclastic sedimentary rocks of the Roberts Mountain allochthon, Miocene intrusive dikes, alluvial deposits of the northern Shoshone Range piedmont, and riverine deposits of the Reese and Humboldt rivers.Significant findings include: refined age estimates for the Ordovician-Cambrian Valmy Formation and Devonian Slaven Chert, based on new fossil information; and detailed mapping of late Quaternary fault traces along the Shoshone Range fault system.

Delineating the Rattlesnake Springs, New Mexico Watershed Using Precision Gravity Techniques

NASA Astrophysics Data System (ADS)

Doser, D. I.; Boykov, N. D.; Baker, M. R.; Kaip, G. M.; Langford, R. P.

2009-12-01

Rattlesnake Springs serves as the sole domestic water source for Carlsbad Caverns National Park. The recent development of oil and gas leases and agricultural lands surrounding the springs has led to concern about contamination of the fracture controlled aquifer system. We have conducted a series of precision gravity surveys (station spacing 200 to 300 m in a 4 x 4 km area), combined with other geophysical studies and geologic mapping, to delineate possible fracture systems in the gypsum and carbonate bedrock that feed the spring system. Our combined results suggest several pathways for water to enter the springs. A series of WNW-ESE striking features are apparent in our gravity data that appear to align with relict spring valleys we have mapped to the west of the springs. A self potential survey indicates that water is entering the springs at a shallow level from the northwest direction. However, gravity data also indicate a north-south trending fracture system could be providing a pathway for water to enter from the south. This is consistent with drawdown tests conducted in the 1950’s and 1960’s on irrigation wells located to the south of the springs. The north-south fracture system appears related to a basin bounding fault system observed in the regional gravity data.

Structural controls on geothermal circulation in Surprise Valley, California: A re-evaluation of the Lake City fault zone

USGS Publications Warehouse

Anne E. Egger,; Glen, Jonathan; McPhee, Darcy K.

2014-01-01

Faults and fractures play an important role in the circulation of geothermal fluids in the crust, and the nature of that role varies according to structural setting and state of stress. As a result, detailed geologic and geophysical mapping that relates thermal springs to known structural features is essential to modeling geothermal systems. Published maps of Surprise Valley in northeastern California suggest that the “Lake City fault” or “Lake City fault zone” is a significant structural feature, cutting obliquely across the basin and connecting thermal springs across the valley. Newly acquired geophysical data (audio-magnetotelluric, gravity, and magnetic), combined with existing geochemical and geological data, suggest otherwise. We examine potential field profiles and resistivity models that cross the mapped Lake City fault zone. While there are numerous geophysical anomalies that suggest subsurface structures, they mostly do not coincide with the mapped traces of the Lake City fault zone, nor do they show a consistent signature in gravity, magnetics, or resistivities that would suggest a through-going fault that would promote connectivity through lateral fluid flow. Instead of a single, continuous fault, we propose the presence of a deformation zone associated with the growth of the range-front Surprise Valley fault. The implication for geothermal circulation is that this is a zone of enhanced porosity but lacks length-wise connectivity that could conduct fluids across the valley. Thermal fluid circulation is most likely controlled primarily by interactions between N-S–trending normal faults.

Influences of spring-to-summer sea surface temperatures over different Indian Ocean domains on the Asian summer monsoon

NASA Astrophysics Data System (ADS)

Li, Zhenning; Yang, Song

2017-11-01

The influences of spring-to-summer sea surface temperature (SST) anomalies in different domains of the Indian Ocean (IO) on the Asian summer monsoon are investigated by conducting a series of numerical experiments using the NCAR CAM4 model. It is found that, to a certain extent, the springtime IO SST anomalies can persist to the summer season. The spring-to-summer IO SST anomalies associated with the IO basin warming mode are strongly linked to the summer climate over Asia, especially the South Asian monsoon (SAM) and the East Asian monsoon. Among this connection, the warming of tropical IO plays the most critical role, and the warming of southern IO is important for monsoon variation and prediction prior to the full development of the monsoon. The atmospheric response to IO basin wide warming is similar with that to tropical IO warming. The influence of northern IO warming on the SAM, however, is opposite to the effect of southern IO warming. Meanwhile, the discrepancies between the results from idealized SST forcing simulations and observations, especially for the southern IO, reveal that the dominant role of air-sea interaction in the monsoon-IO coupled system cannot be ignored. Moreover, the springtime northern IO warming seems to favor an early onset or a stronger persistence of the SAM.

Ancient Hydrothermal Springs in Arabia Terra, Mars

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Allen, Carlton C.

2008-01-01

Hydrothermal springs are important astrobiological sites for several reasons: 1) On Earth, molecular phylogeny suggests that many of the most primitive organisms are hyperthermophiles, implying that life on this planet may have arisen in hydrothermal settings; 2) on Mars, similar settings would have supplied energy- and nutrient-rich waters in which early martian life may have evolved; 3) such regions on Mars would have constituted oases of continued habitability providing warm, liquid water to primitive life forms as the planet became colder and drier; and 4) mineralization associated with hydrothermal settings could have preserved biosignatures from those martian life forms. Accordingly, if life ever developed on Mars, then hydrothermal spring deposits would be excellent localities in which to search for morphological or chemical remnants of that life. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel which allows detailed analysis of geologic structure and geomorphology. Based on these new data, we report several features in Vernal Crater, Arabia Terra that we interpret as ancient hydrothermal springs.

Terrestrial carbon cycle affected by non-uniform climate warming

NASA Astrophysics Data System (ADS)

Xia, Jianyang; Chen, Jiquan; Piao, Shilong; Ciais, Philippe; Luo, Yiqi; Wan, Shiqiang

2014-03-01

Feedbacks between the terrestrial carbon cycle and climate change could affect many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The rate of climate warming varies on diurnal and seasonal timescales. A synthesis of global air temperature data reveals a greater rate of warming in winter than in summer in northern mid and high latitudes, and the inverse pattern in some tropical regions. The data also reveal a decline in the diurnal temperature range over 51% of the global land area and an increase over only 13%, because night-time temperatures in most locations have risen faster than daytime temperatures. Analyses of satellite data, model simulations and in situ observations suggest that the impact of seasonal warming varies between regions. For example, spring warming has largely stimulated ecosystem productivity at latitudes between 30° and 90° N, but suppressed productivity in other regions. Contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. We argue that ascertaining the effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research.

Climate Warming Threatens Semi-arid Forests in Inner Asia

NASA Astrophysics Data System (ADS)

WU, X.; Liu, H.; Qi, Z.; Li, X.

2014-12-01

A line of evidences reveal an increasing tree growth decline and tree mortality mainly attributable to climate warming and the warming-mediated changes in drought and other processes (such as fire and insect dynamics) in many parts of world tropical, temperate and boreal forests. However, the growth responses to climate change of the widely distributed semi-arid forests are unclear. Here, we synthetically investigate the tree growth patterns during past decades and its interannual response to climate variations in Inner Asia combining the ground truth field survey and samplings, remote sensing observations and climate data. We identified a pervasive tree growth decline since mid-1990s in semi-arid forests in Inner Asia. The widely observed tree growth decline is dominantly attributable to warming-induced water stress during pre- and early growing season. Tree growth of semi-arid forests in Inner Asia is particularly susceptible to spring warming and has been suffering a prolonged growth limitation in recent decades due to spring warming-mediated water conditions. Additionally, we identified a much slower growth rate in younger trees and a lack of tree regeneration in these semi-arid forests. The widely observed forest growth reduction and lack of tree regeneration over semi-arid forests in Inner Asia could predictably exert great effects on forest structure, regionally/globally biophysical and biochemical processes and the feedbacks between biosphere and atmosphere. Notably, further increases in forest stress and tree mortality could be reasonably expected, especially in context of the increase frequency and severity of high temperature and heat waves and changes in forest disturbances, potentially driving the eventual regional loss of current semi-arid forests. Given the potential risks of climate induced forest dieback, increased management attention to adaptation options for enhancing forest resistance and resilience to projected climate stress can be expected

Gas exchange, growth, and defense responses of invasive Alliaria petiolata (Brassicaceae) and native Geum vernum (Rosaceae) to elevated atmospheric CO2 and warm spring temperatures.

PubMed

Anderson, Laurel J; Cipollini, Don

2013-08-01

Global increases in atmospheric CO2 and temperature may interact in complex ways to influence plant physiology and growth, particularly for species that grow in cool, early spring conditions in temperate forests. Plant species may also vary in their responses to environmental changes; fast-growing invasives may be more responsive to rising CO2 than natives and may increase production of allelopathic compounds under these conditions, altering species' competitive interactions. We examined growth and physiological responses of Alliaria petiolata, an allelopathic, invasive herb, and Geum vernum, a co-occurring native herb, to ambient and elevated spring temperatures and atmospheric CO2 conditions in a factorial growth chamber experiment. At 5 wk, leaves were larger at high temperature, and shoot biomass increased under elevated CO2 only at high temperature in both species. As temperatures gradually warmed to simulate seasonal progression, G. vernum became responsive to CO2 at both temperatures, whereas A. petiolata continued to respond to elevated CO2 only at high temperature. Elevated CO2 increased thickness and decreased nitrogen concentrations in leaves of both species. Alliaria petiolata showed photosynthetic downregulation at elevated CO2, whereas G. vernum photosynthesis increased at elevated temperature. Flavonoid and cyanide concentrations decreased significantly in A. petiolata leaves in the elevated CO2 and temperature treatment. Total glucosinolate concentrations and trypsin inhibitor activities did not vary among treatments. Future elevated spring temperatures and CO2 will interact to stimulate growth for A. petiolata and G. vernum, but there may be reduced allelochemical effects in A. petiolata.

Simulated climate warming alters phenological synchrony between an outbreak insect herbivore and host trees.

PubMed

Schwartzberg, Ezra G; Jamieson, Mary A; Raffa, Kenneth F; Reich, Peter B; Montgomery, Rebecca A; Lindroth, Richard L

2014-07-01

As the world's climate warms, the phenologies of interacting organisms in seasonally cold environments may advance at differing rates, leading to alterations in phenological synchrony that can have important ecological consequences. For temperate and boreal species, the timing of early spring development plays a key role in plant-herbivore interactions and can influence insect performance, outbreak dynamics, and plant damage. We used a field-based, meso-scale free-air forest warming experiment (B4WarmED) to examine the effects of elevated temperature on the phenology and performance of forest tent caterpillar (Malacosoma disstria) in relation to the phenology of two host trees, aspen (Populus tremuloides) and birch (Betula papyrifera). Results of our 2-year study demonstrated that spring phenology advanced for both insects and trees, with experimentally manipulated increases in temperature of 1.7 and 3.4 °C. However, tree phenology advanced more than insect phenology, resulting in altered phenological synchrony. Specifically, we observed a decrease in the time interval between herbivore egg hatch and budbreak of aspen in both years and birch in one year. Moreover, warming decreased larval development time from egg hatch to pupation, but did not affect pupal mass. Larvae developed more quickly on aspen than birch, but pupal mass was not affected by host species. Our study reveals that warming-induced phenological shifts can alter the timing of ecological interactions across trophic levels. These findings illustrate one mechanism by which climate warming could mediate insect herbivore outbreaks, and also highlights the importance of climate change effects on trophic interactions.

Mantle to Surface Fluid Transfer Above a Flat Slab Subduction Zone: Isotopic Evidence from Hot Springs in the Cordillera Blanca, Peru

NASA Astrophysics Data System (ADS)

Newell, D. L.; Jessup, M. J.; Hilton, D. R.; Shaw, C. A.; Hughes, C. A.

2015-12-01

Thermal springs in the Cordillera Blanca, Peru, provide geochemical evidence for deeply circulated hydrothermal fluids that carry significant mantle-derived helium. The Cordillera Blanca is a ~200 km-long NNW-SSE trending mountain range in the Peruvian Andes located above an amagmatic flat-slab subduction segment. The west side of the range is bounded by the Cordillera Blanca detachment that preserves a progression of top to the west ductile shear to brittle normal faulting since ~5 Ma. We report aqueous and stable isotope geochemical results from fluid and gas samples collected in 2013 and 2015 from 13 hot springs emanating from the Cordillera Blanca detachment and associated hanging wall faults. Most springs are vigorously bubbling (degassing), and range in temperature, pH, and conductivity from 17-89 °C, 5.95-8.87, and 0.17-21.5 mS, respectively. The hottest springs issue directly from the northern segment of the detachment. Geochemically, springs are CO2-rich, alkaline-chloride to alkaline-carbonate waters, with elevated trace metal contents including Fe, Cu, As, Zn, Sb, and Tl. Notably, As contents are ≤11 ppm, indicating that thermal waters may be adversely impacting local water quality. Water δ18O and δD, trends in elemental chemistry, and cation geothermometry collectively demonstrate mixing of hot (200-260 °C) saline fluid with cold meteoric recharge along the fault. Helium isotope ratios (3He/4He) for dissolved gases in the hot springs range from 0.62 to 1.98 RC/RA, indicating the presence of ~25% mantle-derived helium, assuming mixing of an asthenospheric end-member with the crustal helium reservoir. CO2/3He and carbon stable isotope ratios indicate a carbon source derived from mixing of crustal sources with minor mantle carbon. Overall, the volatile signature overlaps with orogen-wide datasets where crustal overprinting has modified mantle contributions at active arc volcanoes. Given the long duration since active magmatism in the Cordillera

Natural radioactivity in geothermal waters, Alhambra Hot Springs and nearby areas, Jefferson County, Montana

USGS Publications Warehouse

Leonard, Robert B.; Janzer, Victor J.

1978-01-01

Radioactive hot springs issue from a fault zone in crystalline rock of the Boulder batholith at Alhambra, Jefferson County, in southwestern Montana. The discharge contains high concentrations of radon, and the gross alpha activity and the concentration of adium-226 exceed maximum levels recommended by the Environmental Protection Agency for drinking water. Part of the discharge is diverted for space heating, bathing, and domestic use. The radioactive thermal waters at measured temperatures of about 60°C are of the sodium bicarbonate type and saturated with respect to calcium carbonate. Radium-226 in the rock and on fractured surfaces or coprecipitated with calcium carbonate probably is the principal source of radon that is dissolved in the thermal water and discharged with other gases from some wells and springs. Local surface water and shallow ground water are of the calcium bicarbonate type and exhibit low background activity. The temperature, percent sodium, and radioactivity of mixed waters adjacent to the fault zone increase with depth. Samples from most of the major hot springs in southwestern Montana have been analyzed for gross alpha and beta activity. The high level of radioactivity at Alhambra appears to be related to leaching of radioactive material from siliceous veins by ascending thermal waters and is not a normal characteristic of hot springs issuing from fractured crystalline rock in Montana.

NGEE Arctic Zero Power Warming PhenoCamera Images, Barrow, Alaska, 2016

DOE Data Explorer

Shawn Serbin; Andrew McMahon; Keith Lewin; Kim Ely; Alistair Rogers

2016-11-14

StarDot NetCam SC pheno camera images collected from the top of the Barrow, BEO Sled Shed. The camera was installed to monitor the BNL TEST group's prototype ZPW (Zero Power Warming) chambers during the growing season of 2016 (including early spring and late fall). Images were uploaded to the BNL FTP server every 10 minutes and renamed with the date and time of the image. See associated data "Zero Power Warming (ZPW) Chamber Prototype Measurements, Barrow, Alaska, 2016" http://dx.doi.org/10.5440/1343066.

Earlier vegetation green-up has reduced spring dust storms

PubMed Central

Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

2014-01-01

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p < 0.01) between green-up date and dust storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = −0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world. PMID:25343265

Earlier vegetation green-up has reduced spring dust storms.

PubMed

Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

2014-10-24

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p < 0.01) between green-up date and dust storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = -0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world.

Sources, Fluxes, and Effects of Fluids in the Alpine Fault Zone, South Island, New Zealand

NASA Astrophysics Data System (ADS)

Menzies, C. D.; Teagle, D. A. H.; Niedermann, S.; Cox, S.; Craw, D.; Zimmer, M.; Cooper, M. J.; Erzinger, J.

2015-12-01

Historic ruptures on some plate boundary faults occur episodically. Fluids play a key role in modifying the chemical and physical properties of fault zones, which may prime them for repeated rupture by the generation of high pore fluid pressures. Modelling of fluid loss rates from fault zones has led to estimates of fluid fluxes required to maintain overpressure (Faulkner and Rutter, 2001), but fluid sources and fluxes, and permeability evolution in fault zones remain poorly constrained. High mountains in orogenic belts can drive meteoric water to the middle crust, and metamorphic water is generated during rock dehydration. Additionally, fluids from the mantle are transported into the crust when fluid pathways are created by tectonism or volcanism. Here we use geochemical tracers to determine fluid flow budgets for meteoric, metamorphic and mantle fluids at a major compressional tectonic plate boundary. The Alpine Fault marks the transpressional Pacific-Australian plate boundary through South Island of New Zealand, it has historically produced large earthquakes (Mw ~8) and is late in its 329±68 year seismic cycle, having last ruptured in 1717. We present strontium isotope ratios of hot springs and hydrothermal minerals that trace fluid flow paths in and around the Alpine Fault to illustrate that the fluid flow regime is restricted by low cross-fault permeability. Fluid-rock interaction limits cross-fault fluid flow by the precipitating clays and calcite that infill pore spaces and fractures in the Alpine Fault alteration zone. In contrast, helium isotopes ratios measured in hot springs near to the fault (0.15-0.81 RA) indicate the fault acts as a conduit for mantle fluids from below. Mantle fluid fluxes are similar to the San Andreas Fault (<1x10-5 m3m-2/yr) and insufficient to promote fault weakening. The metamorphic fluid flux is of similar magnitude to the mantle flux. The dominant fluid throughout the seismogenic zone is meteoric in origin (secondary mineral �

Increasing western US forest wildfire activity: sensitivity to changes in the timing of spring.

PubMed

Westerling, Anthony LeRoy

2016-06-05

Prior work shows western US forest wildfire activity increased abruptly in the mid-1980s. Large forest wildfires and areas burned in them have continued to increase over recent decades, with most of the increase in lightning-ignited fires. Northern US Rockies forests dominated early increases in wildfire activity, and still contributed 50% of the increase in large fires over the last decade. However, the percentage growth in wildfire activity in Pacific northwestern and southwestern US forests has rapidly increased over the last two decades. Wildfire numbers and burned area are also increasing in non-forest vegetation types. Wildfire activity appears strongly associated with warming and earlier spring snowmelt. Analysis of the drivers of forest wildfire sensitivity to changes in the timing of spring demonstrates that forests at elevations where the historical mean snow-free season ranged between two and four months, with relatively high cumulative warm-season actual evapotranspiration, have been most affected. Increases in large wildfires associated with earlier spring snowmelt scale exponentially with changes in moisture deficit, and moisture deficit changes can explain most of the spatial variability in forest wildfire regime response to the timing of spring.This article is part of the themed issue 'The interaction of fire and mankind'. © 2016 The Author(s).

Increasing western US forest wildfire activity: sensitivity to changes in the timing of spring

PubMed Central

2016-01-01

Prior work shows western US forest wildfire activity increased abruptly in the mid-1980s. Large forest wildfires and areas burned in them have continued to increase over recent decades, with most of the increase in lightning-ignited fires. Northern US Rockies forests dominated early increases in wildfire activity, and still contributed 50% of the increase in large fires over the last decade. However, the percentage growth in wildfire activity in Pacific northwestern and southwestern US forests has rapidly increased over the last two decades. Wildfire numbers and burned area are also increasing in non-forest vegetation types. Wildfire activity appears strongly associated with warming and earlier spring snowmelt. Analysis of the drivers of forest wildfire sensitivity to changes in the timing of spring demonstrates that forests at elevations where the historical mean snow-free season ranged between two and four months, with relatively high cumulative warm-season actual evapotranspiration, have been most affected. Increases in large wildfires associated with earlier spring snowmelt scale exponentially with changes in moisture deficit, and moisture deficit changes can explain most of the spatial variability in forest wildfire regime response to the timing of spring. This article is part of the themed issue ‘The interaction of fire and mankind’. PMID:27216510

Project DAFNE - Drilling Active Faults in Northern Europe

NASA Astrophysics Data System (ADS)

Kukkonen, I. T.; Ask, M. S. V.; Olesen, O.

2012-04-01

We are currently developing a new ICDP project 'Drillling Active Faults in Northern Europe' (DAFNE) which aims at investigating, via scientific drilling, the tectonic and structural characteristics of postglacial (PG) faults in northern Fennoscandia, including their hydrogeology and associated deep biosphere [1, 2]. During the last stages of the Weichselian glaciation (ca. 9,000 - 15,000 years B.P.), reduced ice load and glacially affected stress field resulted in active faulting in Fennoscandia with fault scarps up to 160 km long and 30 m high. These postglacial (PG) faults are usually SE dipping, SW-NE oriented thrusts, and represent reactivated, pre-existing crustal discontinuities. Postglacial faulting indicates that the glacio-isostatic compensation is not only a gradual viscoelastic phenomenon, but includes also unexpected violent earthquakes, suggestively larger than other known earthquakes in stable continental regions. The research is anticipated to advance science in neotectonics, hydrogeology and deep biosphere studies, and provide important information for nuclear waste and CO2 disposal, petroleum exploration on the Norwegian continental shelf and studies of mineral resources in PG fault areas. We expect that multidisciplinary research applying shallow and deep drilling of postglacial faults would provide significant scientific results through generating new data and models, namely: (1) Understanding PG fault genesis and controls of their locations; (2) Deep structure and depth extent of PG faults; (3) Textural, mineralogical and physical alteration of rocks in the PG faults; (4) State of stress and estimates of paleostress of PG faults; (5) Hydrogeology, hydrochemistry and hydraulic properties of PG faults; (6) Dating of tectonic reactivation(s) and temporal evolution of tectonic systems hosting PG faults; (7) Existence/non-existence of deep biosphere in PG faults; (8) Data useful for planning radioactive waste disposal in crystalline bedrock; (9) Data

Forage plants of an Arctic-nesting herbivore show larger warming response in breeding than wintering grounds, potentially disrupting migration phenology.

PubMed

Lameris, Thomas K; Jochems, Femke; van der Graaf, Alexandra J; Andersson, Mattias; Limpens, Juul; Nolet, Bart A

2017-04-01

During spring migration, herbivorous waterfowl breeding in the Arctic depend on peaks in the supply of nitrogen-rich forage plants, following a "green wave" of grass growth along their flyway to fuel migration and reproduction. The effects of climate warming on forage plant growth are expected to be larger at the Arctic breeding grounds than in temperate wintering grounds, potentially disrupting this green wave and causing waterfowl to mistime their arrival on the breeding grounds. We studied the potential effect of climate warming on timing of food peaks along the migratory flyway of the Russian population of barnacle geese using a warming experiment with open-top chambers. We measured the effect of 1.0-1.7°C experimental warming on forage plant biomass and nitrogen concentration at three sites along the migratory flyway (temperate wintering site, temperate spring stopover site, and Arctic breeding site) during 2 months for two consecutive years. We found that experimental warming increased biomass accumulation and sped up the decline in nitrogen concentration of forage plants at the Arctic breeding site but not at temperate wintering and stop-over sites. Increasing spring temperatures in the Arctic will thus shorten the food peak of nitrogen-rich forage at the breeding grounds. Our results further suggest an advance of the local food peak in the Arctic under 1-2°C climate warming, which will likely cause migrating geese to mistime their arrival at the breeding grounds, particularly considering the Arctic warms faster than the temperate regions. The combination of a shorter food peak and mistimed arrival is likely to decrease goose reproductive success under climate warming by reducing growth and survival of goslings after hatching.

Advances and Environmental Conditions of Spring Migration Phenology of American White Pelicans

NASA Astrophysics Data System (ADS)

King, D. Tommy; Wang, Guiming; Yang, Zhiqiang; Fischer, Justin W.

2017-01-01

Spring migration phenology of birds has advanced under warming climate. Migration timing of short-distance migrants is believed to be responsive to environmental changes primarily under exogenous control. However, understanding the ecological causes of the advancement in avian spring migration phenology is still a challenge due to the lack of long-term precise location data. We used 11 years of Global Positioning System relocation data to determine four different migration dates of the annual migration cycle of the American white pelican (Pelecanus erythrorhynchos), a short-distance migrant. We also tested the hypothesis that increases in winter temperature and precipitation on the wintering grounds would advance pelican spring migration. Pelican spring departures and arrivals advanced steadily from 2002 to 2011. Spring departure timing exhibited high repeatability at the upper end of migration timing repeatability reported in literature. However, individual spring departure and arrival dates were not related to winter daily temperature, total winter precipitation, and detrended vegetation green-up dates indexed by the normalized difference vegetation index. Despite high repeatability, the observed between-year variation of spring departure dates was still sufficient for the advancement of spring departure timing.

Advances and Environmental Conditions of Spring Migration Phenology of American White Pelicans.

PubMed

King, D Tommy; Wang, Guiming; Yang, Zhiqiang; Fischer, Justin W

2017-01-16

Spring migration phenology of birds has advanced under warming climate. Migration timing of short-distance migrants is believed to be responsive to environmental changes primarily under exogenous control. However, understanding the ecological causes of the advancement in avian spring migration phenology is still a challenge due to the lack of long-term precise location data. We used 11 years of Global Positioning System relocation data to determine four different migration dates of the annual migration cycle of the American white pelican (Pelecanus erythrorhynchos), a short-distance migrant. We also tested the hypothesis that increases in winter temperature and precipitation on the wintering grounds would advance pelican spring migration. Pelican spring departures and arrivals advanced steadily from 2002 to 2011. Spring departure timing exhibited high repeatability at the upper end of migration timing repeatability reported in literature. However, individual spring departure and arrival dates were not related to winter daily temperature, total winter precipitation, and detrended vegetation green-up dates indexed by the normalized difference vegetation index. Despite high repeatability, the observed between-year variation of spring departure dates was still sufficient for the advancement of spring departure timing.

Long Valley caldera and the UCERF depiction of Sierra Nevada range-front faults

USGS Publications Warehouse

Hill, David P.; Montgomery-Brown, Emily K.

2015-01-01

Long Valley caldera lies within a left-stepping offset in the north-northwest-striking Sierra Nevada range-front normal faults with the Hilton Creek fault to the south and Hartley Springs fault to the north. Both Uniform California Earthquake Rupture Forecast (UCERF) 2 and its update, UCERF3, depict slip on these major range-front normal faults as extending well into the caldera, with significant normal slip on overlapping, subparallel segments separated by ∼10  km. This depiction is countered by (1) geologic evidence that normal faulting within the caldera consists of a series of graben structures associated with postcaldera magmatism (intrusion and tumescence) and not systematic down-to-the-east displacements consistent with distributed range-front faulting and (2) the lack of kinematic evidence for an evolving, postcaldera relay ramp structure between overlapping strands of the two range-front normal faults. The modifications to the UCERF depiction described here reduce the predicted shaking intensity within the caldera, and they are in accord with the tectonic influence that underlapped offset range-front faults have on seismicity patterns within the caldera associated with ongoing volcanic unrest.

Models of Formation and Activity of Spring Mounds in the Mechertate-Chrita-Sidi El Hani System, Eastern Tunisia: Implications for the Habitability of Mars

PubMed Central

Essefi, Elhoucine; Komatsu, Goro; Fairén, Alberto G.; Chan, Marjorie A.; Yaich, Chokri

2014-01-01

Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH) system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early) to the islet (“island”) stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i) the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii) the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii) indurated eolian sedimentation and erosional remnants are common features on

Models of formation and activity of spring mounds in the mechertate-chrita-sidi el hani system, eastern Tunisia: implications for the habitability of Mars.

PubMed

Essefi, Elhoucine; Komatsu, Goro; Fairén, Alberto G; Chan, Marjorie A; Yaich, Chokri

2014-08-28

Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH) system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early) to the islet ("island") stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i) the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii) the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii) indurated eolian sedimentation and erosional remnants are common features on Mars

Radioactive mineral springs in Delta County, Colorado

USGS Publications Warehouse

Cadigan, Robert A.; Rosholt, John N.; Felmlee, J. Karen

1976-01-01

The system of springs in Delta County, Colo., contains geochemical clues to the nature and location of buried uranium-mineralized rock. The springs, which occur along the Gunnison River and a principal tributary between Delta and Paonia, are regarded as evidence of a still-functioning hydrothermal system. Associated with the springs are hydrogen sulfide and sulfur dioxide gas seeps, carbon dioxide gas-powered geysers, thick travertine deposits including radioactive travertine, and a flowing warm-water (41?C) radioactive well. Geochemical study of the springs is based on surface observations, on-site water-property measurements, and sampling of water, travertine, soft precipitates, and mud. The spring deposits are mostly carbonates, sulfates, sulfides, and chlorides that locally contain notable amounts of some elements, such as arsenic, barium, lithium, and radium. Samples from five localities have somewhat different trace element assemblages even though they are related to the same hydrothermal system. All the spring waters but one are dominated by sodium chloride or sodium bicarbonate. The exception is an acid sulfate water with a pH of 2.9, which contains high concentrations of aluminum and iron. Most of the detectable radioactivity is due to the presence of radium-226, a uranium daughter product, but at least one spring precipitate contains abundant radium-228, a thorium daughter product. The 5:1 ratio of radium-228 to radium-226 suggests the proximity of a vein-type deposit as a source for the radium. The proposed locus of a thorium-uranium mineral deposit is believed to lie in the vicinity of Paonia, Colo. Exact direction and depth are not determinable from data now available.

Identification the geothermal system using 1-D audio-magnetotelluric inversion in Lamongan volcano field, East Java, Indonesia

NASA Astrophysics Data System (ADS)

Ilham, N.; Niasari, S. W.

2018-04-01

Tiris village, Probolinggo, East Java, is one of geothermal potential areas in Indonesia. This area is located in a valley flank of Mount Lamongan and Argopuro volcanic complex. This research aimed to identify a geothermal system at Tiris area, particularly the fluid pathways. The geothermal potential can be seen from the presence of warm springs with temperature ranging 35-45°C. The warm spring locations are aligned in the same orientation with major fault structure in the area. The fault structure shows dominant northwest-southeast orientation. We used audio-magnetotelluric data in the frequency range of 10 Hz until 92 kHz. The total magnetotelluric sites are 6. From the data analysis, most of the data orientation were 2-D with geo-electrical direction north-south. We used 1-D inversion using Newton algorithm. The 1-D inversion resulted in low resistive anomaly that corresponds to Lamongan lavas. Additionally, the depth of the resistor are different between the area to the west (i.e. 75 m) and to the east (i.e. 25 m). This indicates that there is a fault around the aligned maar (e.g. Ranu Air).

Geophysical Characterization of the Hilton Creek Fault System

NASA Astrophysics Data System (ADS)

Lacy, A. K.; Macy, K. P.; De Cristofaro, J. L.; Polet, J.

2016-12-01

The Long Valley Caldera straddles the eastern edge of the Sierra Nevada Batholith and the western edge of the Basin and Range Province, and represents one of the largest caldera complexes on Earth. The caldera is intersected by numerous fault systems, including the Hartley Springs Fault System, the Round Valley Fault System, the Long Valley Ring Fault System, and the Hilton Creek Fault System, which is our main region of interest. The Hilton Creek Fault System appears as a single NW-striking fault, dipping to the NE, from Davis Lake in the south to the southern rim of the Long Valley Caldera. Inside the caldera, it splays into numerous parallel faults that extend toward the resurgent dome. Seismicity in the area increased significantly in May 1980, following a series of large earthquakes in the vicinity of the caldera and a subsequent large earthquake swarm which has been suggested to be the result of magma migration. A large portion of the earthquake swarms in the Long Valley Caldera occurs on or around the Hilton Creek Fault splays. We are conducting an interdisciplinary geophysical study of the Hilton Creek Fault System from just south of the onset of splay faulting, to its extension into the dome of the caldera. Our investigation includes ground-based magnetic field measurements, high-resolution total station elevation profiles, Structure-From-Motion derived topography and an analysis of earthquake focal mechanisms and statistics. Preliminary analysis of topographic profiles, of approximately 1 km in length, reveals the presence of at least three distinct fault splays within the caldera with vertical offsets of 0.5 to 1.0 meters. More detailed topographic mapping is expected to highlight smaller structures. We are also generating maps of the variation in b-value along different portions of the Hilton Creek system to determine whether we can detect any transition to more swarm-like behavior towards the North. We will show maps of magnetic anomalies, topography

Geology, tephrochronology, radiometric ages, and cross sections of the Mark West Springs 7.5' quadrangle, Sonoma and Napa counties, California

USGS Publications Warehouse

McLaughlin, R.J.; Sarna-Wojicki, A. M.; Fleck, R.J.; Wright, W.H.; Levin, V.R.G.; Valin, Z.C.

2004-01-01

The purpose of this geologic map is to provide a context within which to interpret the Neogene evolution of the active strike-slip fault system traversing the Mark West Springs 7.5' quadrangle and adjacent areas. Based on this geologic framework, the timing and total amounts of displacement and the Neogene rates of slip for faults of the right-stepover area between the Healdsburg and Maacama Faults are addressed.The Mark West Springs quadrangle is located in the northern California Coast Ranges north of San Francisco Bay. It is underlain by Mesozoic rocks of the Franciscan Complex, the Coast Range ophiolite, and the Great Valley sequence, considered here to be the pre-Tertiary basement of the northern Coast Ranges. These rocks are overlain by a complexly interstratified and mildly to moderately deformed sequence of Pleistocene to late Miocene marine and nonmarine sedimentary and largely subaerial volcanic rocks. These rocks and unconformably overlying, less-deformed Holocene and Pleistocene strata are cut by the active right-lateral Healdsburg and Maacama Fault Zones.Mapping of the Mark West Springs quadrangle began in 1996 and was completed in October 2002. Most of the mapping presented here is original, although a few other sources of existing geologic mapping were also utilized. Funding for the project was provided by the National Cooperative Geologic Mapping and Earthquake Hazards Reduction programs of the U.S. Geological Survey, in cooperation with geologic hazards mapping investigations of the California Geological Survey.

Do summer temperatures trigger spring maturation in pacific lamprey, Entosphenus tridentatus?

USGS Publications Warehouse

Clemens, B.J.; Van De Wetering, S.; Kaufman, J.; Holt, R.A.; Schreck, C.B.

2009-01-01

Pacific lamprey, Entosphenus tridentatus, return to streams and use somatic energy to fuel maturation. Body size decreases, the lamprey mature, spawn, and then die. We predicted that warm, summer temperatures (>20 ??C) would accentuate shrinkage in body size, and expedite sexual maturation and subsequent death. We compared fish reared in the laboratory at diel fluctuating temperatures of 20-24 ??C (mean = 21.8 ??C) with fish reared at cooler temperatures (13.6 ??C). The results confirmed our predictions. Lamprey from the warm water group showed significantly greater proportional decreases in body weight following the summer temperature treatments than fish from the cool water group. A greater proportion of warm water fish sexually matured (100%) and died (97%) the following spring than cool water fish (53% sexually mature, 61% died). Females tended to mature and die earlier than males, most obviously in the warm water group. ?? 2009 John Wiley & Sons A/S.

Temperature and composition of carbonate cements record early structural control on cementation in a nascent deformation band fault zone: Moab Fault, Utah, USA

NASA Astrophysics Data System (ADS)

Hodson, Keith R.; Crider, Juliet G.; Huntington, Katharine W.

2016-10-01

Fluid-driven cementation and diagenesis within fault zones can influence host rock permeability and rheology, affecting subsequent fluid migration and rock strength. However, there are few constraints on the feedbacks between diagenetic conditions and structural deformation. We investigate the cementation history of a fault-intersection zone on the Moab Fault, a well-studied fault system within the exhumed reservoir rocks of the Paradox Basin, Utah, USA. The fault zone hosts brittle structures recording different stages of deformation, including joints and two types of deformation bands. Using stable isotopes of carbon and oxygen, clumped isotope thermometry, and cathodoluminescence, we identify distinct source fluid compositions for the carbonate cements within the fault damage zone. Each source fluid is associated with different carbonate precipitation temperatures, luminescence characteristics, and styles of structural deformation. Luminescent carbonates appear to be derived from meteoric waters mixing with an organic-rich or magmatic carbon source. These cements have warm precipitation temperatures and are closely associated with jointing, capitalizing on increases in permeability associated with fracturing during faulting and subsequent exhumation. Earlier-formed non-luminescent carbonates have source fluid compositions similar to marine waters, low precipitation temperatures, and are closely associated with deformation bands. The deformation bands formed at shallow depths very early in the burial history, preconditioning the rock for fracturing and associated increases in permeability. Carbonate clumped isotope temperatures allow us to associate structural and diagenetic features with burial history, revealing that structural controls on fluid distribution are established early in the evolution of the host rock and fault zone, before the onset of major displacement.

Slip rates and spatially variable creep on faults of the northern San Andreas system inferred through Bayesian inversion of Global Positioning System data

USGS Publications Warehouse

Murray, Jessica R.; Minson, Sarah E.; Svarc, Jerry L.

2014-01-01

Fault creep, depending on its rate and spatial extent, is thought to reduce earthquake hazard by releasing tectonic strain aseismically. We use Bayesian inversion and a newly expanded GPS data set to infer the deep slip rates below assigned locking depths on the San Andreas, Maacama, and Bartlett Springs Faults of Northern California and, for the latter two, the spatially variable interseismic creep rate above the locking depth. We estimate deep slip rates of 21.5 ± 0.5, 13.1 ± 0.8, and 7.5 ± 0.7 mm/yr below 16 km, 9 km, and 13 km on the San Andreas, Maacama, and Bartlett Springs Faults, respectively. We infer that on average the Bartlett Springs fault creeps from the Earth's surface to 13 km depth, and below 5 km the creep rate approaches the deep slip rate. This implies that microseismicity may extend below the locking depth; however, we cannot rule out the presence of locked patches in the seismogenic zone that could generate moderate earthquakes. Our estimated Maacama creep rate, while comparable to the inferred deep slip rate at the Earth's surface, decreases with depth, implying a slip deficit exists. The Maacama deep slip rate estimate, 13.1 mm/yr, exceeds long-term geologic slip rate estimates, perhaps due to distributed off-fault strain or the presence of multiple active fault strands. While our creep rate estimates are relatively insensitive to choice of model locking depth, insufficient independent information regarding locking depths is a source of epistemic uncertainty that impacts deep slip rate estimates.

Gravity and magnetic data across the Ghost Dance Fault in WT-2 Wash, Yucca Mountain, Nevada

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

Oliver, H.W.; Sikora, R.F.

1994-12-31

Detailed gravity and ground magnetic data were obtained in September 1993 along a 4,650 ft-long profile across the Ghost Dance Fault system in WT-2 Wash. Gravity stations were established every 150 feet along the profile. Total-field magnetic measurements made initially every 50 ft along the profile, then remade every 20 ft through the fault zone. These new data are part of a geologic and geophysical study of the Ghost Dance Fault (GDF) which includes detailed geologic mapping, seismic reflection, and some drilling including geologic and geophysical logging. The Ghost Dance Fault is the only through-going fault that has been identifiedmore » within the potential repository for high-level radioactive waste at Yucca Mountain, Nevada. Preliminary gravity results show a distinct decrease of 0.1 to 0.2 mGal over a 600-ft-wide zone to the east of and including the mapped fault. The gravity decrease probably marks a zone of brecciation. Another fault-offset located about 2,000 ft to the east of the GDF was detected by seismic reflection data and is also marked by a distinct gravity low. The ground magnetic data show a 200-ft-wide magnetic low of about 400 nT centered about 100 ft east of the Ghost Dance Fault. The magnetic low probably marks a zone of brecciation within the normally polarized Topopah Spring Tuff, the top of which is about 170 ft below the surface, and which is known from drilling to extend to a depth of about 1,700 ft. Three-component magnetometer logging in drill hole WT-2 located about 2,700 ft east of the Ghost Dance Fault shows that the Topopah Spring Tuff is strongly polarized magnetically in this area, so that fault brecciation of a vertical zone within the Tuff could provide an average negative magnetic contrast of the 4 Am{sup {minus}1} needed to produce the 400 nT low observed at the surface.« less

Effects of growth temperature and winter duration on leaf phenology of a spring ephemeral (Gagea lutea) and a summergreen forb (Maianthemum dilatatum).

PubMed

Yoshie, Fumio

2008-09-01

Effects of growth temperature and winter duration on leaf longevity were compared between a spring ephemeral, Gagea lutea, and a forest summergreen forb, Maianthemum dilatatum. The plants were grown at day/night temperatures of 25/20 degrees C and 15/10 degrees C after a chilling treatment for variable periods at 2 degrees C. The temperature regime of 25/20 degrees C was much higher than the mean air temperatures for both species in their native habitats. Warm temperature of 25/20 degrees C and/or long chilling treatment shortened leaf longevity in G. lutea, but not in M. dilatatum. The response of G. lutea was consistent with that reported for other spring ephemerals. Air temperature increases as the vegetative season progresses. The decrease in leaf longevity in G. lutea under warm temperature condition ensures leaf senescence in summer, an unfavorable season for its growth. This also implies that early leaf senescence could occur in years with early summers. Warm spring temperatures have been shown to accelerate the leafing-out of forest trees. The decrease in leaf longevity due to warm temperature helps synchronize the period of leaf senescence roughly with the time of the forest canopy leaf-out. Prolonged winter due to late snowmelt has been shown to shorten the vegetative period for spring ephemerals. The decrease in leaf longevity due to long chilling treatment would correspond with this shortened vegetative period.

Continuous but diverse advancement of spring-summer phenology in response to climate warming across the Qinghai-Tibetan Plateau

DOE PAGES

Zheng, Zhoutao; Zhu, Wenquan; Chen, Guangsheng; ...

2016-04-25

The Qinghai-Tibetan Plateau (QTP) is more vulnerable and sensitive to climate change than many other regions worldwide because of its high altitude, permafrost geography, and harsh physical environment. As a sensitive bio-indicator of climate change, plant phenology shift in this region has been intensively studied during the recent decades, primarily based on satellite-retrieved data. However, great controversy still exists regarding the change in direction and magnitudes of spring-summer phenology. Based on a large number (11,000+ records) of long-term and continuous ground observational data for various plant species, our study intended to more comprehensively assess the changing trends of spring-summer phenologymore » and their relationships with climatic change across the QTP. The results indicated a continuous advancement (–2.69 days decade –1) in spring-summer phenology from 1981 to 2011, with an even more rapid advancement during 2000–2011 (–3.13 days decade –1), which provided new field evidence for continuous advancement in spring-summer phenology across the QTP. However, diverse advancing rates in spring-summer phenology were observed for different vegetation types, thermal conditions, and seasons. The advancing trends matched well with the difference in sensitivity of spring-summer phenology to increasing temperature, implying that the sensitivity of phenology to temperature was one of the major factors influencing spring-summer phenology shifts. Besides, increased precipitation could advance the spring-summer phenology. As a result, the response of spring-summer phenology to temperature tended to be stronger from east to west across all species, while the response to precipitation showed no consistent spatial pattern.« less

Continuous but diverse advancement of spring-summer phenology in response to climate warming across the Qinghai-Tibetan Plateau

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

Zheng, Zhoutao; Zhu, Wenquan; Chen, Guangsheng

The Qinghai-Tibetan Plateau (QTP) is more vulnerable and sensitive to climate change than many other regions worldwide because of its high altitude, permafrost geography, and harsh physical environment. As a sensitive bio-indicator of climate change, plant phenology shift in this region has been intensively studied during the recent decades, primarily based on satellite-retrieved data. However, great controversy still exists regarding the change in direction and magnitudes of spring-summer phenology. Based on a large number (11,000+ records) of long-term and continuous ground observational data for various plant species, our study intended to more comprehensively assess the changing trends of spring-summer phenologymore » and their relationships with climatic change across the QTP. The results indicated a continuous advancement (–2.69 days decade –1) in spring-summer phenology from 1981 to 2011, with an even more rapid advancement during 2000–2011 (–3.13 days decade –1), which provided new field evidence for continuous advancement in spring-summer phenology across the QTP. However, diverse advancing rates in spring-summer phenology were observed for different vegetation types, thermal conditions, and seasons. The advancing trends matched well with the difference in sensitivity of spring-summer phenology to increasing temperature, implying that the sensitivity of phenology to temperature was one of the major factors influencing spring-summer phenology shifts. Besides, increased precipitation could advance the spring-summer phenology. As a result, the response of spring-summer phenology to temperature tended to be stronger from east to west across all species, while the response to precipitation showed no consistent spatial pattern.« less

Mechanisms of Robust Future Spring Drying in the Southwest U.S. in CMIP5 Models

NASA Astrophysics Data System (ADS)

Ting, M.; Seager, R.; Li, C.; Liu, H.

2017-12-01

The net surface water budget, precipitation minus evaporation (P-E), shows a clear seasonal cycle in the American Southwest with net gain of surface water (positive P-E) in the cold half of the year (October to March) and net loss of water (negative P-E) in the warmer half (April - September), with June and July being the driest time of the year. There is a significant shift of the summer drying toward earlier in the year under CO2 warming scenario, resulting in substantial spring drying (MAM) of the American Southwest, from the near-term future (2021 - 2040) to the end of the current Century with gradually increasing magnitude. While the spring drying has been identified in previous studies, its mechanism has not been fully addressed. Using moisture budget analysis, we found that the drying is mainly due to decreased mean moisture convergence, partially compensated by the increase in transient eddy moisture flux convergence. The decreased mean moisture convergence is further separated into those due to changes in circulation (dynamic changes) and changes in atmospheric moisture content (thermodynamic changes). The drying is found to be dominated by the thermodynamic driven changes in column averaged moisture convergence, due mainly to increased dry zonal advection caused by the climatological land-ocean thermal contrast, rather than by the well-known "dry gets drier" mechanism. Furthermore, the enhanced dry advection in the warming climate is dominated by the robust zonal mean atmospheric warming, thus the spring drying in Southwest US is very robust. We also discuss reasons this future drying is particularly strong in the spring as compared to the other seasons.

Informing geobiology through GIS site suitability analysis: locating springs in mantle units of ophiolites

NASA Astrophysics Data System (ADS)

Bowman, A.; Cardace, D.; August, P.

2012-12-01

Springs sourced in the mantle units of ophiolites serve as windows to the deep biosphere, and thus hold promise in elucidating survival strategies of extremophiles, and may also inform discourse on the origin of life on Earth. Understanding how organisms can survive in extreme environments provides clues to how microbial life responds to gradients in pH, temperature, and oxidation-reduction potential. Spring locations associated with serpentinites have traditionally been located using a variety of field techniques. The aqueous alteration of ultramafic rocks to serpentinites is accompanied by the production of very unusual formation fluids, accessed by drilling into subsurface flow regimes or by sampling at related surface springs. The chemical properties of these springs are unique to water associated with actively serpentinizing rocks; they reflect a reducing subsurface environment reacting at low temperatures producing high pH, Ca-rich formation fluids with high dissolved hydrogen and methane. This study applies GIS site suitability analysis to locate high pH springs upwelling from Coast Range Ophiolite serpentinites in Northern California. We used available geospatial data (e.g., geologic maps, topography, fault locations, known spring locations, etc.) and ArcGIS software to predict new spring localities. Important variables in the suitability model were: (a) bedrock geology (i.e., unit boundaries and contacts for peridotite, serpentinite, possibly pyroxenite, or chromite), (b) fault locations, (c) regional data for groundwater characteristics such as pH, Ca2+, and Mg2+, and (d) slope-aspect ratio. The GIS model derived from these geological and environmental data sets predicts the latitude/longitude points for novel and known high pH springs sourced in serpentinite outcrops in California. Field work confirms the success of the model, and map output can be merged with published environmental microbiology data (e.g., occurrence of hydrogen-oxidizers) to showcase

Warm summers during the Younger Dryas cold reversal.

PubMed

Schenk, Frederik; Väliranta, Minna; Muschitiello, Francesco; Tarasov, Lev; Heikkilä, Maija; Björck, Svante; Brandefelt, Jenny; Johansson, Arne V; Näslund, Jens-Ove; Wohlfarth, Barbara

2018-04-24

The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons.

Heat flow and energetics of the San Andreas fault zone.

USGS Publications Warehouse

Lachenbruch, A.H.; Sass, J.H.

1980-01-01

Approximately 100 heat flow measurements in the San Andreas fault zone indicate 1) there is no evidence for local frictional heating of the main fault trace at any latitude over a 1000-km length from Cape Mendocino to San Bernardino, 2) average heat flow is high (ca.2 HFU, ca.80 mW m-2) throughout the 550-km segment of the Coast Ranges that encloses the San Andreas fault zone in central California; this broad anomaly falls off rapidly toward the Great Valley to the east, and over a 200-km distance toward the Mendocino Triple Junction to the northwest. As others have pointed out, a local conductive heat flow anomaly would be detectable unless the frictional resistance allocated to heat production on the main trace were less than 100 bars. Frictional work allocated to surface energy of new fractures is probably unimportant, and hydrologic convection is not likely to invalidate the conduction assumption, since the heat discharge by thermal springs near the fault is negligible. -Authors

Earthquake mechanism and predictability shown by a laboratory fault

USGS Publications Warehouse

King, C.-Y.

1994-01-01

Slip events generated in a laboratory fault model consisting of a circulinear chain of eight spring-connected blocks of approximately equal weight elastically driven to slide on a frictional surface are studied. It is found that most of the input strain energy is released by a relatively few large events, which are approximately time predictable. A large event tends to roughen stress distribution along the fault, whereas the subsequent smaller events tend to smooth the stress distribution and prepare a condition of simultaneous criticality for the occurrence of the next large event. The frequency-size distribution resembles the Gutenberg-Richter relation for earthquakes, except for a falloff for the largest events due to the finite energy-storage capacity of the fault system. Slip distributions, in different events are commonly dissimilar. Stress drop, slip velocity, and rupture velocity all tend to increase with event size. Rupture-initiation locations are usually not close to the maximum-slip locations. ?? 1994 Birkha??user Verlag.

Influence of spring phenology on seasonal and annual carbon balance in two contrasting New England forests.

PubMed

Richardson, Andrew D; Hollinger, David Y; Dail, D Bryan; Lee, John T; Munger, J William; O'keefe, John

2009-03-01

Spring phenology is thought to exert a major influence on the carbon (C) balance of temperate and boreal ecosystems. We investigated this hypothesis using four spring onset phenological indicators in conjunction with surface-atmosphere CO(2) exchange data from the conifer-dominated Howland Forest and deciduous-dominated Harvard Forest AmeriFlux sites. All phenological measures, including CO(2) source-sink transition dates, could be well predicted on the basis of a simple two-parameter spring warming model, indicating good potential for improving the representation of phenological transitions and their dynamic responsiveness to climate variability in land surface models. The date at which canopy-scale photosynthetic capacity reached a threshold value of 12 micromol m(-2) s(-1) was better correlated with spring and annual flux integrals than were either deciduous or coniferous bud burst dates. For all phenological indicators, earlier spring onset consistently, but not always significantly, resulted in higher gross primary productivity (GPP) and ecosystem respiration (RE) for both seasonal (spring months, April-June) and annual flux integrals. The increase in RE was less than that in GPP; depending on the phenological indicator used, a one-day advance in spring onset increased springtime net ecosystem productivity (NEP) by 2-4 g C m(-2) day(-1). In general, we could not detect significant differences between the two forest types in response to earlier spring, although the response to earlier spring was generally more pronounced for Harvard Forest than for Howland Forest, suggesting that future climate warming may favor deciduous species over coniferous species, at least in this region. The effect of earlier spring tended to be about twice as large when annual rather than springtime flux integrals were considered. This result is suggestive of both immediate and lagged effects of earlier spring onset on ecosystem C cycling, perhaps as a result of accelerated N cycling

High autumn temperature delays spring bud burst in boreal trees, counterbalancing the effect of climatic warming.

PubMed

Heide, O M

2003-09-01

The effect of temperature during short-day (SD) dormancy induction was examined in three boreal tree species in a controlled environment. Saplings of Betula pendula Roth, B. pubescens Ehrh. and Alnus glutinosa (L.) Moench. were exposed to 5 weeks of 10-h SD induction at 9, 15 and 21 degrees C followed by chilling at 5 degrees C for 40, 70, 100 and 130 days and subsequent forcing at 15 degrees C in a 24-h photoperiod for 60 days. In all species and with all chilling periods, high temperature during SD dormancy induction significantly delayed bud burst during subsequent flushing at 15 degrees C. In A. glutinosa, high temperature during SD dormancy induction also significantly increased the chilling requirement for dormancy release. Field experiments at 60 degrees N with a range of latitudinal birch populations revealed a highly significant correlation between autumn temperature and days to bud burst in the subsequent spring. September temperature alone explained 20% of the variation between years in time of bud burst. In birch populations from 69 and 71 degrees N, which ceased growing and shed their leaves in August when the mean temperature was 15 degrees C, bud burst occurred later than expected compared with lower latitude populations (56 degrees N) in which dormancy induction took place more than 2 months later at a mean temperature of about 6 degrees C. It is concluded that this autumn temperature response may be important for counterbalancing the potentially adverse effects of higher winter temperatures on dormancy stability of boreal trees during climate warming.

Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters.

PubMed

Oczkowski, Autumn; McKinney, Richard; Ayvazian, Suzanne; Hanson, Alana; Wigand, Cathleen; Markham, Erin

2015-01-01

Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. A recent survey and synthesis of data from four locations in Southern Rhode Island has led us to hypothesize that this warming may be amplified in the shallow (<1 m), nearshore portions of these estuaries. While intertidal areas are not typically selected as locations for long-term monitoring, we compiled data from published literature, theses, and reports that suggest that enhanced warming may be occurring, perhaps at rates three times higher than deeper estuarine waters. Warmer spring waters may be one of the factors influencing biota residing in intertidal regions both in general as well as at our specific sites. We observed greater abundance of fish, and size of Menidia sp., in recent (2010-2012) seine surveys compared to similar collections in 1962. While any linkages are speculative and data are preliminary, taken together they suggest that shallow intertidal portions of estuaries may be important places to look for the effects of climate change.

The San Andreas Fault System, California

USGS Publications Warehouse

Wallace, Robert E.

1990-01-01

.; J.G. Vedder, offshore reglor south of lat 35° N.; and D.G. Herd, southern San Francisco Bay region. The Fault Evaluation Program of the California Division of Mines and Geology under the direction of E.W. Hart, provided much data about many faults. Unpublished material about the Bartlett Springs fault zone that was gathered by Geomatrix Consultants for the Pacific Gas and Electric Co. was very useful. In addition, selected publications that provided invaluable data include Bortugno (1982), Herd (1977), Herd and Helley (1977), Pampeyan and others (1981), and Yerkes and others (1980). 

Geologic map of the Gila Hot Springs 7.5' quadrangle and the Cliff Dwellings National Monument, Catron and Grant Counties, New Mexico

USGS Publications Warehouse

Ratté, James C.; Gaskill, David L.; Chappell, James R.

2014-01-01

The Gila Hot Springs quadrangle is of geologic interest with respect to four major features, which are: 1)\tThe caves of the Gila Cliff Dwellings National Monument 2)\tThe hot springs associated with the faults of the Gila Hot Springs graben 3)\tThe Alum Mountain rhyolite dome and eruptive center 4)\tA proposed segment of the southeastern wall of the Gila Cliff Dwellings caldera The Gila Cliff Dwellings National Monument consists of two tracts. The caves that were inhabited by the Mogollon people in the 14th century are in the main tract near the mouth of Cliff Dweller Canyon in the Little Turkey Park 7.5' quadrangle adjoining the northwest corner of the Gila Hot Springs quadrangle. The second tract includes the Cliff Dwellings National Monument Visitor Center at the confluence of the West and Middle Forks of the Gila River in the northwest corner of the Gila Hot Springs quadrangle. Both quadrangles are within the Gila National Forest and the Gila Wilderness except for a narrow corridor that provides access to the National Monument and the small ranching and residential community at Gila Center in the Gila River valley. The caves in Cliff Dweller Canyon were developed in the Gila Conglomerate of probable Miocene? and Pleistocene? age in this area by processes of lateral corrosion and spring sapping along the creek in Cliff Dweller Canyon. The hot springs in the Gila River valley are localized along faults in the deepest part of the Gila Hot Springs graben, which cuts diagonally northwest-southeast across the central part of the quadrangle. Some of the springs provide domestic hot water for space heating and agriculture in the Gila River valley and represent a possible thermal resource for development at the Cliff Dwellings National Monument. The Alum Mountain rhyolite dome and eruptive center in the southwestern part of the quadrangle is a colorful area of altered and mineralized rocks that is satellitic to the larger Copperas Canyon eruptive center, both being

Anatomy of landslides along the Dead Sea Transform Fault System in NW Jordan

NASA Astrophysics Data System (ADS)

Dill, H. G.; Hahne, K.; Shaqour, F.

2012-03-01

In the mountainous region north of Amman, Jordan, Cenomanian calcareous rocks are being monitored constantly for their mass wasting processes which occasionally cause severe damage to the Amman-Irbid Highway. Satellite remote sensing data (Landsat TM, ASTER, and SRTM) and ground measurements are applied to investigate the anatomy of landslides along the Dead Sea Transform Fault System (DSTFS), a prominent strike-slip fault. The joints and faults pertinent to the DSTFS match the architectural elements identified in landslides of different size. This similarity attests to a close genetic relation between the tectonic setting of one of the most prominent fault zones on the earth and modern geomorphologic processes. Six indicators stand out in particular: 1) The fractures developing in N-S and splay faults represent the N-S lateral movement of the DSTFS. They governed the position of the landslides. 2) Cracks and faults aligned in NE-SW to NNW-SSW were caused by compressional strength. They were subsequently reactivated during extensional processes and used in some cases as slip planes during mass wasting. 3) Minor landslides with NE-SW straight scarps were derived from compressional features which were turned into slip planes during the incipient stages of mass wasting. They occur mainly along the slopes in small wadis or where a wide wadi narrows upstream. 4) Major landslides with curved instead of straight scarps and rotational slides are representative of a more advanced level of mass wasting. These areas have to be marked in the maps and during land management projects as high-risk area mainly and may be encountered in large wadis with steep slopes or longitudinal slopes undercut by road construction works. 5) The spatial relation between minor faults and slope angle is crucial as to the vulnerability of the areas in terms of mass wasting. 6) Springs lined up along faults cause serious problems to engineering geology in that they step up the behavior of marly

Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

PubMed

Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

2010-10-01

Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more

Illuminating Northern California’s Active Faults

USGS Publications Warehouse

Prentice, Carol S.; Crosby, Christopher J.; Whitehill, Caroline S.; Arrowsmith, J. Ramon; Furlong, Kevin P.; Philips, David A.

2009-01-01

Newly acquired light detection and ranging (lidar) topographic data provide a powerful community resource for the study of landforms associated with the plate boundary faults of northern California (Figure 1). In the spring of 2007, GeoEarthScope, a component of the EarthScope Facility construction project funded by the U.S. National Science Foundation, acquired approximately 2000 square kilometers of airborne lidar topographic data along major active fault zones of northern California. These data are now freely available in point cloud (x, y, z coordinate data for every laser return), digital elevation model (DEM), and KMZ (zipped Keyhole Markup Language, for use in Google EarthTM and other similar software) formats through the GEON OpenTopography Portal (http://www.OpenTopography.org/data). Importantly, vegetation can be digitally removed from lidar data, producing high-resolution images (0.5- or 1.0-meter DEMs) of the ground surface beneath forested regions that reveal landforms typically obscured by vegetation canopy (Figure 2)

Change in failure stress on the southern San Andreas fault system caused by the 1992 magnitude = 7.4 Landers earthquake

USGS Publications Warehouse

Stein, R.S.; King, G.C.P.; Lin, J.

1992-01-01

The 28 June Landers earthquake brought the San Andreas fault significantly closer to failure near San Bernardino, a site that has not sustained a large shock since 1812. Stress also increased on the San Jacinto fault near San Bernardino and on the San Andreas fault southeast of Palm Springs. Unless creep or moderate earthquakes relieve these stress changes, the next great earthquake on the southern San Andreas fault is likely to be advanced by one to two decades. In contrast, stress on the San Andreas north of Los Angeles dropped, potentially delaying the next great earthquake there by 2 to 10 years.

Future vegetation ecosystem response to warming climate over the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Bao, Y.; Gao, Y.; Wang, Y.

2017-12-01

The amplified vegetation response to climate variability has been found over the Tibetan Plateau (TP) in recent decades. In this study, the potential impacts of 21st century climate change on the vegetation ecosystem over the TP are assessed based on the dynamic vegetation outputs of models from Coupled Model Intercomparison Project Phase 5 (CMIP5), and the sensitivity of the TP vegetation in response to warming climate was investigated. Models project a continuous and accelerating greening in future, especially in the eastern TP, which closely associates with the plant type upgrade due to the pronouncing warming in growing season.Vegetation leaf area index (LAI) increase well follows the global warming, suggesting the warming climate instead of co2 fertilization controlls the future TP plant growth. The warming spring may advance the start of green-up day and extend the growing season length. More carbon accumulation in vegetation and soil will intensify the TP carbon cycle and will keep it as a carbon sink in future. Keywords: Leaf Area Index (LAI), Climate Change, Global Dynamic Vegetation Models (DGVMs), CMIP5, Tibetan Plateau (TP)

ncreasing altitudinal spring phenology gradient of vegetation over the last decade in Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Shen, M.; Piao, S.

2013-12-01

Vegetation spring phenology in temperate and cold regions is widely expected to advance with temperature elevation and is often used as an indicator of regional climatic change. The Qinghai-Tibetan Plateau (QTP) has experienced intensive warming recently, but substantial contradictions exist about the changes of vegetation spring phenology. We investigated spatiotemporal variations in green-up dates in the QTP from 2000 to 2011 determined through five methods using four satellite-derived datasets including the normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR), Système Pour l'Observation de la Terre, and MODerate resolution Imaging Spectroradiometer (MODIS), and the enhanced vegetation index from MODIS. On regional scale, no significant temporal trends (all P > 0.05) were found in the green-up dates, consistently among all the vegetation indices and methods. This insignificance was resulted from the substantial spatial heterogeneity of trends in green-up date, with delay by greater than 0.5 day yr-1 in the southwest region, and extensive advance in the other areas, although the temperature elevation was region-wide. These changes doubled the altitudinal gradient of green-up date, from 0.63 day 100m-1 in the early 2000s to 1.30 days 100m-1 in the early 2010s. The delay in the southwest region and high altitudes was likely caused by the decline in spring precipitation, despite the increasing spring temperature. This study suggests that spring precipitation is an important regulator of phenological response to climatic warming in QTP, and that, even in cold region, delay of vegetation spring phenology does not necessarily indicate spring cooling. Besides, the phenological changes retrieved from the widely used AVHRR NDVI differed from those from the other 3 vegetation indices, necessitating the use of multi-datasets while monitoring vegetation dynamics from space.

Shallow seismic imaging of folds above the Puente Hills blind-thrust fault, Los Angeles, California

USGS Publications Warehouse

Pratt, T.L.; Shaw, J.H.; Dolan, J.F.; Christofferson, S.A.; Williams, R.A.; Odum, J.K.; Plesch, A.

2002-01-01

High-resolution seismic reflection profiles image discrete folds in the shallow subsurface (<600 m) above two segments of the Puente Hills blind-thrust fault system, Los Angeles basin, California. The profiles demonstrate late Quaternary activity at the fault tip, precisely locate the axial surfaces of folds within the upper 100 m, and constrain the geometry and kinematics of recent folding. The Santa Fe Springs segment of the Puente Hills fault zone shows an upward-narrowing kink band with an active anticlinal axial surface, consistent with fault-bend folding above an active thrust ramp. The Coyote Hills segment shows an active synclinal axial surface that coincides with the base of a 9-m-high scarp, consistent with tip-line folding or the presence of a backthrust. The seismic profiles pinpoint targets for future geologic work to constrain slip rates and ages of past events on this important fault system.

Spring predictability explains different leaf-out strategies in the woody floras of North America, Europe and East Asia.

PubMed

Zohner, Constantin M; Benito, Blas M; Fridley, Jason D; Svenning, Jens-Christian; Renner, Susanne S

2017-04-01

Intuitively, interannual spring temperature variability (STV) should influence the leaf-out strategies of temperate zone woody species, with high winter chilling requirements in species from regions where spring warming varies greatly among years. We tested this hypothesis using experiments in 215 species and leaf-out monitoring in 1585 species from East Asia (EA), Europe (EU) and North America (NA). The results reveal that species from regions with high STV indeed have higher winter chilling requirements, and, when grown under the same conditions, leaf out later than related species from regions with lower STV. Since 1900, STV has been consistently higher in NA than in EU and EA, and under experimentally short winter conditions NA species required 84% more spring warming for bud break, EU ones 49% and EA ones only 1%. These previously unknown continental-scale differences in phenological strategies underscore the need for considering regional climate histories in global change models. © 2017 John Wiley & Sons Ltd/CNRS.

Study of aerosol effect on accelerated snow melting over the Tibetan Plateau during boreal spring

NASA Astrophysics Data System (ADS)

Lee, Woo-Seop; Bhawar, Rohini L.; Kim, Maeng-Ki; Sang, Jeong

2013-08-01

In the present study, a coupled atmosphere-ocean global climate model (CSIRO-Mk3.6) is used to investigate the role of aerosol forcing agents as drivers of snow melting trends in the Tibetan Plateau (TP) region. Anthropogenic aerosol-induced snow cover changes in a warming climate are calculated from the difference between historical run (HIST) and all forcing except anthropogenic aerosol (NoAA). Absorbing aerosols can influence snow cover by warming the atmosphere, reducing snow reflectance after deposition. The warming the rate of snow melt, exposing darker surfaces below to short-wave radiation sooner, and allowing them to heat up even faster in the Himalayas and TP. The results show a strong spring snow cover decrease over TP when absorbing anthropogenic aerosol forcing is considered, whereas snow cover fraction (SCF) trends in NoAA are weakly negative (but insignificant) during 1951-2005. The enhanced spring snow cover trends in HIST are due to overall effects of different forcing agents: When aerosol forcing (AERO) is considered, a significant reduction of SCF than average can be found over the western TP and Himalayas. The large decreasing trends in SCF over the TP, with the maximum reduction of SCF around 12-15% over the western TP and Himalayas slope. Also accelerated snow melting during spring is due to effects of aerosol on snow albedo, where aerosol deposition cause decreases snow albedo. However, the SCF change in the “NoAA” simulations was observed to be less.

[X-ray diffraction and infrared spectrum analysis of fault gouge in Wenchuan seismic belt].

PubMed

Wang, Zheng-Yang; Cao, Jian-Jin; Luo, Song-Ying; Liao, Yi-Peng

2014-05-01

Wenchuan earthquake produced a series of co-seismic surface ruptures in Leigu and Zhaojiagou, and we collected samples of co-seismic fault gouge in the surface ruptures as well as the old gouge in the fault of Nanba. Testing The new and old fault gouge was tested with X-ray diffraction and infrared absorption spectra, and its characteristics such as mineral compositions, clay mineral contents and combinations were comprehensively analyzed. The results display obvious differences between the new and old fault gouge, showing that the old fault gouge is mainly composed of wall rock debris or milled powders, while the main components of new fault gouge are clay minerals. The assemblage of clay minerals composition shows that the environment of the fault activity was mainly warm and humid, and the clay minerals were mainly transformed by low temperature and low pressure dynamic metamorphism. And this also partly indicates that the latest way of the fault activity in this area may be a creeping. However the previous researches on the fault gouge of Wenchuan earthquake fault zone are mainly focused on its mechanical properties as well as its texture and structure, the research in this paper is to determine the physical and chemical environment of fault activity through the mineral compositions and clay mineral contents in the fault gouge characteristics, and this research has important scientific significance to the researches on the evolution of the fault environment and the activity mechanism of the earthquake.

Water Quality Assessment of the Comal Springs Riverine System, New Braunfels, Texas, 1993-94

USGS Publications Warehouse

Fahlquist, Lynne; Slattery, R.N.

1997-01-01

Comal Springs of Central Texas are the largest springs in the southwestern United States. The long-term average flow of the Comal River, which essentially is the flow from Comal Springs, is 284 cubic feet per second (ft3/s). The artesian springs emerge at the base of an escarpment formed by the Comal Springs fault. The Comal River (fig. 1) is approximately 2 miles (mi) long and is a tributary of the Guadalupe River. Most of the Comal River follows the path of an old mill race, here referred to as New Channel, then flows through a channel carved by a tributary stream (Dry Comal Creek), eventually rejoining its original watercourse. The original watercourse, here referred to as Old Channel, has been reduced to a small stream, the source of which is water diverted from Landa Lake and several springs in the channel. In addition to being an important economic resource of the region, the springs and associated river system are home to unique aquatic species such as the endangered fountain darter (Etheostoma fonticola). The Comal Springs riffle beetle (Heterelmis comalensis), which exists in the springflow channel upstream of Landa Lake, has been proposed for listing as endangered. The Comal Springs dryopid beetle (Stygoparmus comalensis) and the Peck’s cave amphipod (Stygobromus pecki) are two subterranean species associated with Comal Springs also proposed for endangered listing.

Vertical structure of recent Arctic warming.

PubMed

Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla

2008-01-03

Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold season and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of warming that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce warming above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of warming can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.

Peatland Structural Controls on Spring Distribution

NASA Astrophysics Data System (ADS)

Hare, D. K.; Boutt, D. F.; Hackman, A. M.; Davenport, G.

2013-12-01

The species richness of wetland ecosystems' are sustained by the presence of discrete groundwater discharge, or springs. Springs provide thermal refugia and a source of fresh water inflow crucial for survival of many wetland species. The subsurface drivers that control the spatial distribution of surficial springs throughout peatland complexes are poorly understood due to the many challenges peatlands pose for hydrologic characterization, such as the internal heterogeneities, soft, dynamic substrate, and low gradient of peat drainage. This has previously made it difficult to collect spatial data required for restoration projects that seek to support spring obligate and thermally stressed species such as trout. Tidmarsh Farms is a 577-acre site in Southeastern Massachusetts where 100+ years of cranberry farming has significantly altered the original peatland hydrodynamics and ecology. Farming practices such as the regular application of sand, straightening of the main channel, and addition of drainage ditches has strongly degraded this peatland ecosystem. Our research has overlain non-invasive geophysical, thermal, and water isotopic data from the Tidmarsh Farms peatland to provide a detailed visualization of how subsurface peat structure and spring patterns correlate. Ground penetrating radar (GPR) has proven particularly useful in characterizing internal peat structure and the mineral soil interface beneath peatlands, we interpolate the peatland basin at a large scale (1 km2) and compare this 3-D surface to the locations of springs on the peat platform. Springs, expressed as cold anomalies in summer and warm anomalies in winter, were specifically located by combining fiber-optic and infrared thermal surveys, utilizing the numerous relic agricultural drainage ditches as a sampling advantage. Isotopic signatures of the spring locations are used to distinguish local and regional discharge, differences that can be explained in part by the peat basin structure

Hot-spring sinter deposits in the Alvord-Pueblo Valley, Harney County, Oregon

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

Cummings, M.L.; St. John, A.M.

1993-04-01

Silica sinter deposits occur at Borax Lake, Alvord Hot Springs, and Mickey Springs in the Alvord-Pueblo Valley. Although the sinter deposits occur in areas of active hot springs, sinter is not being deposited. Hot springs are localized along faults that have been active since the Pleistocene. The sinter deposits formed after the drying of glacial Lake Alvord, but before and during extensive wind deflation of glacial-lacustrine sediments. At Mickey Springs, sinter rests directly on unaltered, unconsolidated lithic-rich sand. At Borax Lake, sinter overlies unaltered diatomite, but some armoring, presumably by silica, of the 30 m vent has developed. Field relationsmore » suggest rapid dumping of silica from solution without alteration of the country rock at the vent. Discharge of thermal fluids and cold groundwater along the same structure may have produced colloidal silica carried in a solution stripped of dissolved silica. Sinter is composed of opal-a, traces of detrital feldspar and quartz, and evaporation-related boracite. The concentration of Sb is similar among the three sinter deposits (20 to 70 ppm); however, As, Cs, and Br are highest at Borax Lake (5 to 560 ppm; 26 to 118 ppm; 5 to 1,040 ppm) while Hg is highest at Mickey Springs (1.0 to 5.2 ppm).« less

Seismicity and Tectonics of the West Kaibab Fault Zone, AZ

NASA Astrophysics Data System (ADS)

Wilgus, J. T.; Brumbaugh, D. S.

2014-12-01

The West Kaibab Fault Zone (WKFZ) is the westernmost bounding structure of the Kaibab Plateau of northern Arizona. The WKFZ is a branching complex of high angle, normal faults downthrown to the west. There are three main faults within the WKFZ, the Big Springs fault with a maximum of 165 m offset, the Muav fault with 350 m of displacement, and the North Road fault having a maximum throw of approximately 90 m. Mapping of geologically recent surface deposits at or crossing the fault contacts indicates that the faults are likely Quaternary with the most recent offsets occurring <1.6 Ma. Slip rates are estimated to be less than 0.2 mm/yr. No historic fault slip has been documented. The WKFZ is one of the most seismically active areas in Arizona and lies within the Northern Arizona Seismic Belt (NASB), which stretches across northern Arizona trending NW-SE. The data set for this study includes 156 well documented events with the largest being a M5.75 in 1959 and including a swarm of seven earthquakes in 2012. The seismic data set (1934-2014) reveals that seismic activity clusters in two regions within the study area, the Fredonia cluster located in the NW corner of the study area and the Kaibab cluster located in the south central portion of the study area. The fault plane solutions to date indicate NE-SW to EW extension is occurring in the study area. Source relationships between earthquakes and faults within the WKFZ have not previously been studied in detail. The goal of this study is to use the seismic data set, the available data on faults, and the regional physiography to search for source relationships for the seismicity. Analysis includes source parameters of the earthquake data (location, depth, and fault plane solutions), and comparison of this output to the known faults and areal physiographic framework to indicate any active faults of the WKFZ, or suggested active unmapped faults. This research contributes to a better understanding of the present nature of

Reliability analysis of the solar array based on Fault Tree Analysis

NASA Astrophysics Data System (ADS)

Jianing, Wu; Shaoze, Yan

2011-07-01

The solar array is an important device used in the spacecraft, which influences the quality of in-orbit operation of the spacecraft and even the launches. This paper analyzes the reliability of the mechanical system and certifies the most vital subsystem of the solar array. The fault tree analysis (FTA) model is established according to the operating process of the mechanical system based on DFH-3 satellite; the logical expression of the top event is obtained by Boolean algebra and the reliability of the solar array is calculated. The conclusion shows that the hinges are the most vital links between the solar arrays. By analyzing the structure importance(SI) of the hinge's FTA model, some fatal causes, including faults of the seal, insufficient torque of the locking spring, temperature in space, and friction force, can be identified. Damage is the initial stage of the fault, so limiting damage is significant to prevent faults. Furthermore, recommendations for improving reliability associated with damage limitation are discussed, which can be used for the redesigning of the solar array and the reliability growth planning.

Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub

PubMed Central

Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

2015-01-01

Global climate models predict an increase in the mean surface air temperature, with a disproportionate increase during winter. Since temperature is a major driver of phenological events in temperate woody perennials, warming is likely to induce changes in a range of these events. We investigated the impact of slightly elevated temperatures (+0.76 °C in the air, +1.35 °C in the soil) during the non-growing season (October–April) on freezing tolerance, carbohydrate metabolism, dormancy release, spring phenology and reproductive output in two blackcurrant (Ribes nigrum) cultivars to understand how winter warming modifies phenological traits in a woody perennial known to have a large chilling requirement and to be sensitive to spring frost. Warming delayed dormancy release more in the cultivar ‘Narve Viking’ than in the cultivar ‘Titania’, but advanced budburst and flowering predominantly in ‘Titania’. Since ‘Narve Viking’ has a higher chilling requirement than ‘Titania’, this indicates that, in high-chilling-requiring genotypes, dormancy responses may temper the effect of warming on spring phenology. Winter warming significantly reduced fruit yield the following summer in both cultivars, corroborating the hypothesis that a decline in winter chill may decrease reproductive effort in blackcurrant. Elevated winter temperatures tended to decrease stem freezing tolerance during cold acclimation and deacclimation, but it did not increase the risk of freeze-induced damage mid-winter. Plants at elevated temperature showed decreased levels of sucrose in stems of both cultivars and flower buds of ‘Narve Viking’, which, in buds, was associated with increased concentrations of glucose and fructose. Hence, winter warming influences carbohydrate metabolism, but it remains to be elucidated whether decreased sucrose levels account for any changes in freezing tolerance. Our results demonstrate that even a slight increase in winter temperature may alter

Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub.

PubMed

Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

2015-03-23

Global climate models predict an increase in the mean surface air temperature, with a disproportionate increase during winter. Since temperature is a major driver of phenological events in temperate woody perennials, warming is likely to induce changes in a range of these events. We investigated the impact of slightly elevated temperatures (+0.76 °C in the air, +1.35 °C in the soil) during the non-growing season (October-April) on freezing tolerance, carbohydrate metabolism, dormancy release, spring phenology and reproductive output in two blackcurrant (Ribes nigrum) cultivars to understand how winter warming modifies phenological traits in a woody perennial known to have a large chilling requirement and to be sensitive to spring frost. Warming delayed dormancy release more in the cultivar 'Narve Viking' than in the cultivar 'Titania', but advanced budburst and flowering predominantly in 'Titania'. Since 'Narve Viking' has a higher chilling requirement than 'Titania', this indicates that, in high-chilling-requiring genotypes, dormancy responses may temper the effect of warming on spring phenology. Winter warming significantly reduced fruit yield the following summer in both cultivars, corroborating the hypothesis that a decline in winter chill may decrease reproductive effort in blackcurrant. Elevated winter temperatures tended to decrease stem freezing tolerance during cold acclimation and deacclimation, but it did not increase the risk of freeze-induced damage mid-winter. Plants at elevated temperature showed decreased levels of sucrose in stems of both cultivars and flower buds of 'Narve Viking', which, in buds, was associated with increased concentrations of glucose and fructose. Hence, winter warming influences carbohydrate metabolism, but it remains to be elucidated whether decreased sucrose levels account for any changes in freezing tolerance. Our results demonstrate that even a slight increase in winter temperature may alter phenological traits in

The interacting effects of food, spring temperature, and global climate cycles on population dynamics of a migratory songbird.

PubMed

Townsend, Andrea K; Cooch, Evan G; Sillett, T Scott; Rodenhouse, Nicholas L; Holmes, Richard T; Webster, Michael S

2016-02-01

Although long-distance migratory songbirds are widely believed to be at risk from warming temperature trends, species capable of attempting more than one brood in a breeding season could benefit from extended breeding seasons in warmer springs. To evaluate local and global factors affecting population dynamics of the black-throated blue warbler (Setophaga caerulescens), a double-brooded long-distance migrant, we used Pradel models to analyze 25 years of mark-recapture data collected in New Hampshire, USA. We assessed the effects of spring temperature (local weather) and the El Niño Southern Oscillation index (a global climate cycle), as well as predator abundance, insect biomass, and local conspecific density on population growth in the subsequent year. Local and global climatic conditions affected warbler populations in different ways. We found that warbler population growth was lower following El Niño years (which have been linked to poor survival in the wintering grounds and low fledging weights in the breeding grounds) than La Niña years. At a local scale, populations increased following years with warm springs and abundant late-season food, but were unaffected by spring temperature following years when food was scarce. These results indicate that the warming temperature trends might have a positive effect on recruitment and population growth of black-throated blue warblers if food abundance is sustained in breeding areas. In contrast, potential intensification of future El Niño events could negatively impact vital rates and populations of this species. © 2015 John Wiley & Sons Ltd.

Mountain-climbing bears protect cherry species from global warming through vertical seed dispersal.

PubMed

Naoe, Shoji; Tayasu, Ichiro; Sakai, Yoichiro; Masaki, Takashi; Kobayashi, Kazuki; Nakajima, Akiko; Sato, Yoshikazu; Yamazaki, Koji; Kiyokawa, Hiroki; Koike, Shinsuke

2016-04-25

In a warming climate, temperature-sensitive plants must move toward colder areas, that is, higher latitude or altitude, by seed dispersal [1]. Considering that the temperature drop with increasing altitude (-0.65°C per 100 m altitude) is one hundred to a thousand times larger than that of the equivalent latitudinal distance [2], vertical seed dispersal is probably a key process for plant escape from warming temperatures. In fact, plant geographical distributions are tracking global warming altitudinally rather than latitudinally, and the extent of tracking is considered to be large in plants with better-dispersed traits (e.g., lighter seeds in wind-dispersed plants) [1]. However, no study has evaluated vertical seed dispersal itself due to technical difficulty or high cost. Here, we show using a stable oxygen isotope that black bears disperse seeds of wild cherry over several hundred meters vertically, and that the dispersal direction is heavily biased towards the mountain tops. Mountain climbing by bears following spring-to-summer plant phenology is likely the cause of this biased seed dispersal. These results suggest that spring- and summer-fruiting plants dispersed by animals may have high potential to escape global warming. Our results also indicate that the direction of vertical seed dispersal can be unexpectedly biased, and highlight the importance of considering seed dispersal direction to understand plant responses to past and future climate change. Copyright © 2016 Elsevier Ltd. All rights reserved.

Traveling waves in a spring-block chain sliding down a slope

NASA Astrophysics Data System (ADS)

Morales, J. E.; James, G.; Tonnelier, A.

2017-07-01

Traveling waves are studied in a spring slider-block model. We explicitly construct front waves (kinks) for a piecewise-linear spinodal friction force. Pulse waves are obtained as the matching of two traveling fronts with identical speeds. Explicit formulas are obtained for the wavespeed and the wave form in the anticontinuum limit. The link with localized waves in a Burridge-Knopoff model of an earthquake fault is briefly discussed.

Traveling waves in a spring-block chain sliding down a slope.

PubMed

Morales, J E; James, G; Tonnelier, A

2017-07-01

Traveling waves are studied in a spring slider-block model. We explicitly construct front waves (kinks) for a piecewise-linear spinodal friction force. Pulse waves are obtained as the matching of two traveling fronts with identical speeds. Explicit formulas are obtained for the wavespeed and the wave form in the anticontinuum limit. The link with localized waves in a Burridge-Knopoff model of an earthquake fault is briefly discussed.

Chemical, isotopic, and gas compositions of selected thermal springs in Arizona, New Mexico, and Utah

USGS Publications Warehouse

Mariner, R.H.; Presser, T.S.; Evans, William C.

1977-01-01

Twenty-seven thermal springs in Arizona, New Mexico, and Utah were sampled for detailed chemical and isotopic analysis. The springs issue sodium chloride, sodium bicarbonate, or sodium mixed-anion waters of near neutral (6.2) to alkaline (9.2) pH. High concentrations of fluoride, more than 8 milligrams per liter, occur in Arizona in waters from Gillard Hot Springs, Castle Hot Springs, and the unnamed spring of Eagle Creek, and in New Mexico from springs along the Gila River. Deuterium compositions of the thermal waters cover the same range as those expected for meteoric waters in the respective areas. The chemical compositions of the thermal waters indicate that Thermo Hot Springs in Utah and Gillard Hot Springs in Arizona represent hydrothermal systems which are at temperatures higher than 125 deg C. Estimates of subsurface temperature based on the quartz and Na-K-Ca geothermometer differ by up to 60 deg C for Monroe, Joseph, Red Hill, and Crater hot springs in Utah. Similar conflicting estimates of aquifer temperature occur for Verde Hot Springs, the springs near Clifton and Coolidge Dam, in Arizona; and the warm springs near San Ysidro, Radium Hot Springs, and San Francisco Hot Springs, in New Mexico. Such disparities could result from mixing, precipitation of calcium carbonate, or perhaps appreciable concentrations of magnesium. (Woodard-USGS)

Subaqueous hot springs in Köyceğiz Lake, Dalyan Channel and Fethiye-Göcek Bay (SW Turkey): Locations, chemistry and origins

NASA Astrophysics Data System (ADS)

Avşar, Özgür; Avşar, Ulaş; Arslan, Şebnem; Kurtuluş, Bedri; Niedermann, Samuel; Güleç, Nilgün

2017-10-01

In this study, horizontal temperature measurements along organized grids have been used to detect subaqueous hot springs. The study area, located in the southwest of Turkey and comprised of Köyceğiz Lake, Dalyan Channel and Fethiye-Göcek Bay, was scanned by measuring temperatures horizontally, 2-3 m above the bottom of the lake or sea. After analyzing the temperature data along the grids, the locations with anomalous temperature values were detected, and divers headed here for further verification. Accordingly, among these anomalies, the divers confirmed seven of them as subaqueous hot springs. Three of these hot springs are located in the Köyceğiz Lake, three of them are located in the Dalyan Channel and one hot spring is located in the Fethiye-Göcek Bay. At the locations where temperature anomalies were detected, the divers collected samples directly from the subaqueous hot spring using a syringe-type sampler. We evaluated these water samples together with samples collected from hot and cold springs on land and from local rivers, lakes and the sea, with an aim to generate a conceptual hydrogeochemical model of the geothermal system in the study area. This model predicts that rainwater precipitating in the highlands percolates through fractures and faults into the deeper parts of the Earth's crust, here it is heated and ascends through the sea bottom via buried faults. Pervious carbonate nappes that are underlain and overlain by impervious rocks create a confined aquifer. The southern boundary of the Carbonate-Marmaris nappes is buried under alluvium and/or sea/lake water bodies and this phenomenon determines whether hot springs occur on land or subaqueous. The chemical and isotopic properties of the hot springs point to seawater mixing at deep levels. Thus, the mixing most probably occurs while the water is ascending through the faults and fractures. The gas geochemistry results reveal that the lowest mantle He contributions occur in the samples from K�

Helium in soil gases of the Roosevelt Hot Springs Known Geothermal Resource Ares, Beaver County, Utah

USGS Publications Warehouse

Hinkle, M.E.; Denton, E.H.; Bigelow, R.C.; Turner, R.L.

1978-01-01

Soil samples were collected in two parallel traverses across the Dome fault zone of the Roosevelt Hot Springs Known Geothermal Resource Area. The samples were sealed in air-tight aluminum cans, and the soil gas was allowed to equilibrate with the atmospheric air in the cans. Gas from the cans was analyzed by mass spectrometry. Samples collected over faults contained anomalously high concentrations of helium. Samples collected close to a geothermal well 884 m deep contained more helium than samples collected near another geothermal well 1370 m deep.

Triggered dynamics in a model of different fault creep regimes

PubMed Central

Kostić, Srđan; Franović, Igor; Perc, Matjaž; Vasović, Nebojša; Todorović, Kristina

2014-01-01

The study is focused on the effect of transient external force induced by a passing seismic wave on fault motion in different creep regimes. Displacement along the fault is represented by the movement of a spring-block model, whereby the uniform and oscillatory motion correspond to the fault dynamics in post-seismic and inter-seismic creep regime, respectively. The effect of the external force is introduced as a change of block acceleration in the form of a sine wave scaled by an exponential pulse. Model dynamics is examined for variable parameters of the induced acceleration changes in reference to periodic oscillations of the unperturbed system above the supercritical Hopf bifurcation curve. The analysis indicates the occurrence of weak irregular oscillations if external force acts in the post-seismic creep regime. When fault motion is exposed to external force in the inter-seismic creep regime, one finds the transition to quasiperiodic- or chaos-like motion, which we attribute to the precursory creep regime and seismic motion, respectively. If the triggered acceleration changes are of longer duration, a reverse transition from inter-seismic to post-seismic creep regime is detected on a larger time scale. PMID:24954397

A remarkable climate warming hiatus over Northeast China since 1998

NASA Astrophysics Data System (ADS)

Sun, Xiubao; Ren, Guoyu; Ren, Yuyu; Fang, Yihe; Liu, Yulian; Xue, Xiaoying; Zhang, Panfeng

2017-07-01

Characteristics and causes of global warming hiatus (GWH) phenomenon have received much attention in recent years. Monthly mean data of land surface air maximum temperature (Tmax), minimum temperature (Tmin), and mean temperature (Tmean) of 118 national stations since 1951 in Northeast China are used in this paper to analyze the changes of land surface air temperature in recent 64 years with an emphasis on the GWH period. The results show that (1) from 1951 to 2014, the warming trends of Tmax, Tmin, and Tmean are 0.20, 0.42, and 0.34 °C/decade respectively for the whole area, with the warming rate of Tmin about two times of Tmax, and the upward trend of Tmean obviously higher than mainland China and global averages; (2) in the period 1998-2014, the annual mean temperature consistently exhibits a cooling phenomenon in Northeast China, and the trends of Tmax, Tmin, and Tmean are -0.36, -0.14, and -0.28 °C/decade respectively; (3) in the GWH period, seasonal mean cooling mainly occurs in northern winter (DJF) and spring (MAM), but northern summer (JJA) and autumn (SON) still experience a warming, implying that the annual mean temperature decrease is controlled by the remarkable cooling of winter and spring; (4) compared to the global and mainland China averages, the hiatus phenomenon is more evident in Northeast China, and the cooling trends are more obvious in the cold season; (5) the Northeast China cooling trend occurs under the circulation background of the negative phase Arctic Oscillation (AO), and it is also closely related to strengthening of the Siberia High (SH) and the East Asian Trough (EAT), and the stronger East Asian winter monsoon (EAWM) over the GWH period.

A positive relationship between spring temperature and productivity in 20 songbird species in the boreal zone.

PubMed

Meller, Kalle; Piha, Markus; Vähätalo, Anssi V; Lehikoinen, Aleksi

2018-03-01

Anthropogenic climate warming has already affected the population dynamics of numerous species and is predicted to do so also in the future. To predict the effects of climate change, it is important to know whether productivity is linked to temperature, and whether species' traits affect responses to climate change. To address these objectives, we analysed monitoring data from the Finnish constant effort site ringing scheme collected in 1987-2013 for 20 common songbird species together with climatic data. Warm spring temperature had a positive linear relationship with productivity across the community of 20 species independent of species' traits (realized thermal niche or migration behaviour), suggesting that even the warmest spring temperatures remained below the thermal optimum for reproduction, possibly due to our boreal study area being closer to the cold edge of all study species' distributions. The result also suggests a lack of mismatch between the timing of breeding and peak availability of invertebrate food of the study species. Productivity was positively related to annual growth rates in long-distance migrants, but not in short-distance migrants. Across the 27-year study period, temporal trends in productivity were mostly absent. The population sizes of species with colder thermal niches had decreasing trends, which were not related to temperature responses or temporal trends in productivity. The positive connection between spring temperature and productivity suggests that climate warming has potential to increase the productivity in bird species in the boreal zone, at least in the short term.

Aquimonas voraii gen. nov., sp. nov., a novel gammaproteobacterium isolated from a warm spring of Assam, India.

PubMed

Saha, P; Krishnamurthi, S; Mayilraj, S; Prasad, G S; Bora, T C; Chakrabarti, T

2005-07-01

A bacterial strain designated GPTSA 20(T), which was isolated from a warm spring in Assam, India, was characterized by using a polyphasic approach. The cells were Gram-negative, aerobic rods, which could not utilize or produce acid from most of the carbohydrates tested. The predominant fatty acids were C(15:0) iso (25.04%), C(17:1) iso omega9c (19.28%), C(16:0) iso (17.73%) and C(11:0) iso 3-OH (9.34%). The G+C content was 75 mol%. From 16S rRNA gene sequence analysis (1433 nucleotides, continuous stretch), it was confirmed that strain GPTSA 20(T) belonged to the class 'Gammaproteobacteria'. The closest 16S rRNA gene sequence similarity found (98.2%) was with an uncultured bacterium clone, NB-03 (accession no. AB117707), from an autotrophic nitrifying biofilm. Among culturable bacteria, the closest sequence similarities were with Fulvimonas soli (93.0%), Silanimonas lenta (92.8%), Thermomonas hydrothermalis (92.4%), Frateuria aurantia (91.9%), Rhodanobacter lindaniclasticus (91.9%), Thermomonas haemolytica (91.9%) and Pseudoxanthomonas taiwanensis (91.8%); similarities of less than 91.8% were obtained with other members of the class 'Gammaproteobacteria'. From the biochemical, physiological, chemotaxonomic and phylogenetic analysis, it was clear that strain GPTSA 20(T) was quite different from members of known genera of the class 'Gammaproteobacteria'. Therefore, it is proposed that strain GPTSA 20(T) represents a novel species within a new genus, with the name Aquimonas voraii gen. nov., sp. nov. The type strain is GPTSA 20(T) (=MTCC 6713(T)=JCM 12896(T)).

AgRISTARS: Supporting research. Spring small grains planting date distribution model

NASA Technical Reports Server (NTRS)

Hodges, T.; Artley, J. A. (Principal Investigator)

1981-01-01

A model was developed using 996 planting dates at 51 LANDSAT segments for spring wheat and spring barley in Minnesota, Montana, North Dakota, and South Dakota in 1979. Daily maximum and minimum temperatures and precipitation were obtained from the cooperative weather stations nearest to each segment. The model uses a growing degree day summation modified for daily temperature range to estimate the beginning of planting and uses a soil surface wetness variable to estimate how a fixed number of planting days are distributed after planting begins. For 1979, the model predicts first, median, and last planting dates with root mean square errors of 7.91, 6.61, and 7.09 days, respectively. The model also provides three or four dates to represent periods of planting activity within the planting season. Although the full model was not tested on an independent data set, it may be suitable in areas other than the U.S. Great Plains where spring small grains are planted as soon as soil and air temperatures become warm enough in the spring for plant growth.

Interactions of fluid and gas movement and faulting in the Colorado Plateau, southeastern Utah

NASA Astrophysics Data System (ADS)

Shipton, Z. K.; Evans, J. P.; Kirschner, D.; Heath, J.; Williams, A.; Dockrill, B.

2002-12-01

The east-west and west-northwest striking Salt Wash and the Little Grand Wash normal faults in the Colorado Plateau of southeastern Utah emit large amounts of CO2 gas from abandon drill holes, springs and a hydrocarbon seep. The leakage of similar CO2 charged water has also occurred in the past as shown by large localized tufa deposits and horizontal veins along the fault traces. These deposits consist of thick tufa terraces and mound extending up to 50 meters from the fault damage zones. The faults cut a north plunging anticline of siltstones, shales, and sandstones, and the fault rocks are fine-grained with clay-rich gouge. The Little Grand Wash fault displaces these rocks approximately 290 m and the Salt Wash graben offsets rocks approximately 130 m; both faults extend at least to the top of the Pennsylvanian Paradox Formation, which contains thick salt horizons 1.5 - 2 km at depth. Well log, geologic surface and geochemical data indicate the CO2 reservoirs and sources have been cut by the faults at depth providing a conduit for the vertical migration of CO2 to the surface, but limited horizontal flow across the fault plane. Three- dimensional flow modals show how the faults damage zones permeability is adjacent to the faults and the leakage though the damage zones is localized near the regional anticlines fold axis. Analysis of the fluids emanating from the faults aims to locate the sources and determine the chemical evolutions of the fluids. δ2H and δ18O isotopic data show that the ground waters are meteoric and have not circulated deeply enough to experience an oxygen-isotope shift. δ13C data and PCO2 values indicate that the gas is external to the ground water systems (i.e., not from soil zone gas or dissolution of carbonate aquifer material alone). 3He/4He ratio 0.30 - 0.31 from springs and geysers indicate that the majority of the gas is crustally derived and contains a minimal component of mantle or magmatic gases. δ13C values of 4 to 5 per mil from

Climate change is advancing spring onset across the U.S. national park system

USGS Publications Warehouse

Monahan, William B.; Rosemartin, Alyssa; Gerst, Katharine L.; Fisichelli, Nicholas A.; Ault, Toby R.; Schwartz, Mark D.; Gross, John E.; Weltzin, Jake F.

2016-01-01

Many U.S. national parks are already at the extreme warm end of their historical temperature distributions. With rapidly warming conditions, park resource management will be enhanced by information on seasonality of climate that supports adjustments in the timing of activities such as treating invasive species, operating visitor facilities, and scheduling climate-related events (e.g., flower festivals and fall leaf-viewing). Seasonal changes in vegetation, such as pollen, seed, and fruit production, are important drivers of ecological processes in parks, and phenology has thus been identified as a key indicator for park monitoring. Phenology is also one of the most proximate biological responses to climate change. Here, we use estimates of start of spring based on climatically modeled dates of first leaf and first bloom derived from indicator plant species to evaluate the recent timing of spring onset (past 10–30 yr) in each U.S. natural resource park relative to its historical range of variability across the past 112 yr (1901–2012). Of the 276 high latitude to subtropical parks examined, spring is advancing in approximately three-quarters of parks (76%), and 53% of parks are experiencing “extreme” early springs that exceed 95% of historical conditions. Our results demonstrate how changes in climate seasonality are important for understanding ecological responses to climate change, and further how spatial variability in effects of climate change necessitates different approaches to management. We discuss how our results inform climate change adaptation challenges and opportunities facing parks, with implications for other protected areas, by exploring consequences for resource management and planning.

Using a binary logistic regression method and GIS for evaluating and mapping the groundwater spring potential in the Sultan Mountains (Aksehir, Turkey)

NASA Astrophysics Data System (ADS)

Ozdemir, Adnan

2011-07-01

SummaryThe purpose of this study is to produce a groundwater spring potential map of the Sultan Mountains in central Turkey, based on a logistic regression method within a Geographic Information System (GIS) environment. Using field surveys, the locations of the springs (440 springs) were determined in the study area. In this study, 17 spring-related factors were used in the analysis: geology, relative permeability, land use/land cover, precipitation, elevation, slope, aspect, total curvature, plan curvature, profile curvature, wetness index, stream power index, sediment transport capacity index, distance to drainage, distance to fault, drainage density, and fault density map. The coefficients of the predictor variables were estimated using binary logistic regression analysis and were used to calculate the groundwater spring potential for the entire study area. The accuracy of the final spring potential map was evaluated based on the observed springs. The accuracy of the model was evaluated by calculating the relative operating characteristics. The area value of the relative operating characteristic curve model was found to be 0.82. These results indicate that the model is a good estimator of the spring potential in the study area. The spring potential map shows that the areas of very low, low, moderate and high groundwater spring potential classes are 105.586 km 2 (28.99%), 74.271 km 2 (19.906%), 101.203 km 2 (27.14%), and 90.05 km 2 (24.671%), respectively. The interpretations of the potential map showed that stream power index, relative permeability of lithologies, geology, elevation, aspect, wetness index, plan curvature, and drainage density play major roles in spring occurrence and distribution in the Sultan Mountains. The logistic regression approach has not yet been used to delineate groundwater potential zones. In this study, the logistic regression method was used to locate potential zones for groundwater springs in the Sultan Mountains. The evolved model

Return of warm conditions in the southeastern Bering Sea: Physics to fluorescence

PubMed Central

Duffy-Anderson, J. T.; Eisner, L. B.; Farley, E. V.; Heintz, R. A.; Mordy, C. W.

2017-01-01

From 2007 to 2013, the southeastern Bering Sea was dominated by extensive sea ice and below-average ocean temperatures. In 2014 there was a shift to reduced sea ice on the southern shelf and above-average ocean temperatures. These conditions continued in 2015 and 2016. During these three years, the spring bloom at mooring site M4 (57.9°N, 168.9°W) occurred primarily in May, which is typical of years without sea ice. At mooring site M2 (56.9°N, 164.1°W) the spring bloom occurred earlier especially in 2016. Higher chlorophyll fluorescence was observed at M4 than at M2. In addition, these three warm years continued the pattern near St. Matthew Island of high concentrations (>1 μM) of nitrite occurring during summer in warm years. Historically, the dominant parameters controlling sea-ice extent are winds and air temperature, with the persistence of frigid, northerly winds in winter and spring resulting in extensive ice. After mid-March 2014 and 2016 there were no cold northerly or northeasterly winds. Cold northerly winds persisted into mid-April in 2015, but did not result in extensive sea ice south of 58°N. The apparent mechanism that helped limit ice on the southeastern shelf was the strong advection of warm water from the Gulf of Alaska through Unimak Pass. This pattern has been uncommon, occurring in only one other year (2003) in a 37-year record of estimated transport through Unimak Pass. During years with no sea ice on the southern shelf (e.g. 2001–2005, 2014–2016), the depth-averaged temperature there was correlated to the previous summers ocean temperature. PMID:28957386

Reduced North American terrestrial primary productivity linked to anomalous Arctic warming

DOE PAGES

Kim, Jin-Soo; Kug, Jong-Seong; Jeong, Su-Jong; ...

2017-07-10

Warming temperatures in the Northern Hemisphere have enhanced terrestrial productivity. Despite the warming trend, North America has experienced more frequent and more intense cold weather events during winters and springs. These events have been linked to anomalous Arctic warming since 1990, and may affect terrestrial processes. Here we analyse many observation data sets and numerical model simulations to evaluate links between Arctic temperatures and primary productivity in North America. We find that positive springtime temperature anomalies in the Arctic have led to negative anomalies in gross primary productivity over most of North America during the last three decades, which amountmore » to a net productivity decline of 0.31 PgC yr -1 across the continent. This decline is mainly explained by two factors: severe cold conditions in northern North America and lower precipitation in the South Central United States. In addition, United States crop-yield data reveal that during years experiencing anomalous warming in the Arctic, yields declined by approximately 1 to 4% on average, with individual states experiencing declines of up to 20%. We conclude that the strengthening of Arctic warming anomalies in the past decades has remotely reduced productivity over North America.« less

Reduced North American terrestrial primary productivity linked to anomalous Arctic warming

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

Kim, Jin-Soo; Kug, Jong-Seong; Jeong, Su-Jong

Warming temperatures in the Northern Hemisphere have enhanced terrestrial productivity. Despite the warming trend, North America has experienced more frequent and more intense cold weather events during winters and springs. These events have been linked to anomalous Arctic warming since 1990, and may affect terrestrial processes. Here we analyse many observation data sets and numerical model simulations to evaluate links between Arctic temperatures and primary productivity in North America. We find that positive springtime temperature anomalies in the Arctic have led to negative anomalies in gross primary productivity over most of North America during the last three decades, which amountmore » to a net productivity decline of 0.31 PgC yr -1 across the continent. This decline is mainly explained by two factors: severe cold conditions in northern North America and lower precipitation in the South Central United States. In addition, United States crop-yield data reveal that during years experiencing anomalous warming in the Arctic, yields declined by approximately 1 to 4% on average, with individual states experiencing declines of up to 20%. We conclude that the strengthening of Arctic warming anomalies in the past decades has remotely reduced productivity over North America.« less

Experimental Whole-Ecosystem Warming Alters Vegetation Phenology in a Boreal Spruce Bog: Initial Results from the SPRUCE Experiment

NASA Astrophysics Data System (ADS)

Richardson, A. D.

2016-12-01

Phenology is one of the most robust indicators of the biological impacts of global change. However, the response of phenology to future environmental conditions still remains highly uncertain because of the challenges associated with conducting realistic manipulative experiments. At the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) experiment in the north-central United States, experimental temperature (0 to +9°C above ambient) and CO2 (ambient and elevated) treatments are being applied to mature, and intact, Picea mariana-Sphagnum spp. bog communities in their native habitat through the use of ten large (approximately 12 m wide, 10 m high) open-topped enclosures. We are tracking vegetation green-up and senescence in these chambers using repeat digital photography. Within each chamber, images are recorded every 30 minutes and uploaded to PhenoCam (http://phenocam.sr.unh.edu), where processed to yield quantitative measures of canopy color. These data are complemented by on-the-ground phenological data collected by human observers. Air warming treatments at SPRUCE began in August 2015. We observed a delay in senescence during autumn 2015 (2-5 days per degree of warming) and an advance in onset during spring 2016 (1-4 days per degree of warming). These patterns are robust across species and methods of phenological observation (i.e. camera-based vs. human observer). And, our results show very little evidence for photoperiod acting as a constraint on the response to warming. Early spring onset and consequent loss of frost hardiness in the warmest chambers proved disadvantageous when a brief period of extreme cold (to -12°C in the control chambers, to -3°C in the +9°C chambers) followed a month of generally mild weather. Foliage mortality for both Larix and Picea was immediate and severe, although both species subsequently re-flushed. These results give support for the hypothesis that warming may enhance the likelihood of spring frost

Revealing fate of CO2 leakage pathways in the Little Grand Wash Fault, Green River, Utah

NASA Astrophysics Data System (ADS)

Han, K.; Han, W. S.; Watson, Z. T.; Guyant, E.; Park, E.

2015-12-01

To assure long-term security of geologic carbon sequestration site, evaluation of natural CO2 leakage should be preceded before actual construction of the CO2 facility by comparing natural and artificial reservoir systems. The Little Grand Wash fault is located at the northwestern margin of the Paradox Basin and roles on a bypass of deep subsurface CO2 and brine water onto the surface, e.g., cold water geyser, CO2 spring, and surface travertine deposits. CO2 degassed out from brine at the Little Grand Wash fault zone may react with formation water and minerals while migrating through the fault conduit. Leakage observed by soil CO2 flux on the fault trace shows this ongoing transition of CO2, from supersaturated condition in deep subsurface to shallow surface equilibria. The present study aims to investigate the reactions induced by changes in hydrological and mineralogical factors inside of the fault zone. The methodology to develop site-specific geochemical model of the Little Grand Wash Fault combines calculated mechanical movements of each fluid end-member, along with chemical reactions among fluid, free CO2 gas and rock formations. Reactive transport modeling was conducted to simulate these property changes inside of the fault zone, using chemistry dataset based on 86 effluent samples of CO2 geysers, springs and in situ formation water from Entrada, Carmel, and Navajo Sandstone. Meanwhile, one- and two-dimensional models were separately developed to delineate features mentioned above. The results from the 3000-year simulation showed an appearance of self-sealing processes near the surface of the fault conduit. By tracking physicochemical changes at the depth of 15 m on the 2-dimensional model, significant changes induced by fluid mixing were indicated. Calculated rates of precipitation for calcite, illite, and pyrite showed increase in 2.6 x 10-4, 2.25 x 10-5, and 3.0 x 10-6 in mineral volume fraction at the depth of 15m, respectively. Concurrently

Net carbon uptake has increased through warming-induced changes in temperate forest phenology

Treesearch

Trevor F. Keenan; Josh Gray; Mark A. Friedl; Michael Toomey; Gil Bohrer; David Y. Hollinger; J. William Munger; John O’Keefe; Hans Peter Schmid; Ian Sue Wing; Bai Yang; Andrew D. Richardson

2014-01-01

The timing of phenological events exerts a strong control over ecosystem function and leads to multiple feedbacks to the climate system1. Phenology is inherently sensitive to temperature (although the exact sensitivity is disputed2) and recent warming is reported to have led to earlier spring, later autumn3,4...

Climate warming enhances snow avalanche risk in the Western Himalayas

PubMed Central

Ballesteros-Cánovas, J. A.; Trappmann, D.; Madrigal-González, J.; Eckert, N.; Stoffel, M.

2018-01-01

Ongoing climate warming has been demonstrated to impact the cryosphere in the Indian Himalayas, with substantial consequences for the risk of disasters, human well-being, and terrestrial ecosystems. Here, we present evidence that the warming observed in recent decades has been accompanied by increased snow avalanche frequency in the Western Indian Himalayas. Using dendrogeomorphic techniques, we reconstruct the longest time series (150 y) of the occurrence and runout distances of snow avalanches that is currently available for the Himalayas. We apply a generalized linear autoregressive moving average model to demonstrate linkages between climate warming and the observed increase in the incidence of snow avalanches. Warming air temperatures in winter and early spring have indeed favored the wetting of snow and the formation of wet snow avalanches, which are now able to reach down to subalpine slopes, where they have high potential to cause damage. These findings contradict the intuitive notion that warming results in less snow, and thus lower avalanche activity, and have major implications for the Western Himalayan region, an area where human pressure is constantly increasing. Specifically, increasing traffic on a steadily expanding road network is calling for an immediate design of risk mitigation strategies and disaster risk policies to enhance climate change adaption in the wider study region. PMID:29535224

Geothermal Target Areas in Colorado as Identified by Remote Sensing Techniques

DOE Data Explorer

Khalid Hussein

2012-02-01

This layer contains the areas identified as targets of potential geothermal activity. The Criteria used to identify the target areas include: hot/warm surface exposures modeled from ASTER/Landsat satellite imagery and geological characteristics, alteration mineral commonly associated with hot springs (clays, Si, and FeOx) modeled from ASTER and Landsat data, Colorado Geological Survey (CGS) known thermal hot springs/wells and heat-flow data points, Colorado deep-seated fault zones, weakened basement identified from isostatic gravity data, and Colorado sedimentary and topographic characteristics.

Effect of temperature on rates of ammonium uptake and nitrification in the western coastal Arctic during winter, spring, and summer

NASA Astrophysics Data System (ADS)

Baer, Steven E.; Connelly, Tara L.; Sipler, Rachel E.; Yager, Patricia L.; Bronk, Deborah A.

2014-12-01

Biogeochemical rate processes in the Arctic are not currently well constrained, and there is very limited information on how rates may change as the region warms. Here we present data on the sensitivity of ammonium (NH4+) uptake and nitrification rates to short-term warming. Samples were collected from the Chukchi Sea off the coast of Barrow, Alaska, during winter, spring, and summer and incubated for 24 h in the dark with additions of 15NH4+ at -1.5, 6, 13, and 20°C. Rates of NH4+ uptake and nitrification were measured in conjunction with bacterial production. In all seasons, NH4+ uptake rates were highest at temperatures similar to current summertime conditions but dropped off with increased warming, indicative of psychrophilic (i.e., cold-loving) microbial communities. In contrast, nitrification rates were less sensitive to temperature and were higher in winter and spring compared to summer. These findings suggest that as the Arctic coastal ecosystem continues to warm, NH4+ assimilation may become increasingly important, relative to nitrification, although the magnitude of NH4+ assimilation would be still be lower than nitrification.

Spring performance tester for miniature extension springs

DOEpatents

Salzbrenner, Bradley; Boyce, Brad

2017-05-16

A spring performance tester and method of testing a spring are disclosed that has improved accuracy and precision over prior art spring testers. The tester can perform static and cyclic testing. The spring tester can provide validation for product acceptance as well as test for cyclic degradation of springs, such as the change in the spring rate and fatigue failure.

Trend and Variability of China Precipitation in Spring and Summer: Linkage to Sea Surface Temperatures

NASA Technical Reports Server (NTRS)

Yang, Fanglin; Lau, K.-M.

2004-01-01

Observational records in the past 50 years show an upward trend of boreal-summer precipitation over central eastern China and a downward trend over northern China. During boreal spring, the trend is upward over southeastern China and downward over central eastern China. This study explores the forcing mechanism of these trends in association with the global sea-surface temperature (SST) variations on the interannual and inter-decadal timescales. Results based on Singular Value Decomposition analyses (SVD) show that the interannual variability of China precipitation in boreal spring and summer can be well defined by two centers of actions for each season, which are co-varying with two interannual modes of SSTs. The first SVD modes of precipitation in spring and summer, which are centered in southeastern China and northern China, respectively, are linked to an ENSO-like mode of SSTs. The second SVD modes of precipitation in both seasons are confined to central eastern China, and are primarily linked to SST variations over the warm pool and Indian Ocean. Features of the anomalous 850-hPa winds and 700-Wa geopotential height corresponding to these modes support a physical mechanism that explains the causal links between the modal variations of precipitation and SSTs. On the decadal and longer timescale, similar causal links are found between the same modes of precipitation and SSTs, except for the case of springtime precipitation over central eastern China. For this case, while the interannual mode of precipitation is positively correlated with the interannual variations of SSTs over the warm pool and Indian Ocean; the inter-decadal mode is negatively correlated with a different SST mode, the North Pacific mode. The later is responsible for the observed downward trend of springtime precipitation over central eastern China. For all other cases, both the interannual and inter-decadal variations of precipitation can be explained by the same mode of SSTs. The upward trend

Mound Spring Complexes in Central Australia: An Analog for Martian Groundwater Fed Outflow Channels?

NASA Technical Reports Server (NTRS)

Clarke, J. D. A.; Stoker, C.

2003-01-01

discharged artesian waters are of low to moderate salinity (700 - 9400 ppm), near neutral pH (6.8-7.3) and warm (20-46 C). The elevated temperatures are due to passage of the groundwater through deeply buried (up to 3 km) aquifers in an region of high heat flow, rather than magmatic heating. The waters also contain high levels of dissolved iron and H2S and less than 1 ppm dissolved oxygen. The water is carried in the Late Jurassic Algebuckina Sandstone beneath the aquaclude of the Bulldog Shale. It is brought near the surface by the mid-Cenozoic Dalhousie anticline and the ground water flow focused along a series of faults that breach the anticline's crest.

Stratigraphic record of Pliocene-Pleistocene basin evolution and deformation within the Southern San Andreas Fault Zone, Mecca Hills, California

NASA Astrophysics Data System (ADS)

McNabb, James C.; Dorsey, Rebecca J.; Housen, Bernard A.; Dimitroff, Cassidy W.; Messé, Graham T.

2017-11-01

A thick section of Pliocene-Pleistocene nonmarine sedimentary rocks exposed in the Mecca Hills, California, provides a record of fault-zone evolution along the Coachella Valley segment of the San Andreas fault (SAF). Geologic mapping, measured sections, detailed sedimentology, and paleomagnetic data document a 3-5 Myr history of deformation and sedimentation in this area. SW-side down offset on the Painted Canyon fault (PCF) starting 3.7 Ma resulted in deposition of the Mecca Conglomerate southwest of the fault. The lower member of the Palm Spring Formation accumulated across the PCF from 3.0 to 2.6 Ma during regional subsidence. SW-side up slip on the PCF and related transpressive deformation from 2.6 to 2.3 Ma created a time-transgressive angular unconformity between the lower and upper members of the Palm Spring Formation. The upper member accumulated in discrete fault-bounded depocenters until initiation of modern deformation, uplift, and basin inversion starting at 0.7 Ma. Some spatially restricted deposits can be attributed to the evolution of fault-zone geometric complexities. However, the deformation events at ca. 2.6 Ma and 0.7 Ma are recorded regionally along 80 km of the SAF through Coachella Valley, covering an area much larger than mapped fault-zone irregularities, and thus require regional explanations. We therefore conclude that late Cenozoic deformation and sedimentation along the SAF in Coachella Valley has been controlled by a combination of regional tectonic drivers and local deformation due to dextral slip through fault-zone complexities. We further propose a kinematic link between the 2.6-2.3 Ma angular unconformity and a previously documented but poorly dated reorganization of plate-boundary faults in the northern Gulf of California at 3.3-2.0 Ma. This analysis highlights the potential for high-precision chronologies in deformed terrestrial deposits to provide improved understanding of local- to regional-scale structural controls on basin

Synchrony in the phenology of a culturally iconic spring flower

NASA Astrophysics Data System (ADS)

Sparks, Tim H.; Mizera, Tadeusz; Wójtowicz, Wanda; Tryjanowski, Piotr

2012-03-01

We examine the flowering phenology of the cultural iconic Spring Snowflake Leucojum vernum, a considerable tourist attraction, recorded from two sites in western Poland. Flowering dates at the two sites were closely correlated but about 6 days later at the more natural area. The end of flowering was associated with the start of canopy leafing. Early flowering was related to a longer flowering season which may benefit ecotourism under future climate warming.

Inversion for slip distribution using teleseismic P waveforms: North Palm Springs, Borah Peak, and Michoacan earthquakes

USGS Publications Warehouse

Mendoza, C.; Hartzell, S.H.

1988-01-01

We have inverted the teleseismic P waveforms recorded by stations of the Global Digital Seismograph Network for the 8 July 1986 North Palm Springs, California, the 28 October 1983 Borah Peak, Idaho, and the 19 September 1985 Michoacan, Mexico, earthquakes to recover the distribution of slip on each of the faults using a point-by-point inversion method with smoothing and positivity constraints. Results of the inversion indicate that the Global digital Seismograph Network data are useful for deriving fault dislocation models for moderate to large events. However, a wide range of frequencies is necessary to infer the distribution of slip on the earthquake fault. Although the long-period waveforms define the size (dimensions and seismic moment) of the earthquake, data at shorter period provide additional constraints on the variation of slip on the fault. Dislocation models obtained for all three earthquakes are consistent with a heterogeneous rupture process where failure is controlled largely by the size and location of high-strength asperity regions. -from Authors

Interacting faults

NASA Astrophysics Data System (ADS)

Peacock, D. C. P.; Nixon, C. W.; Rotevatn, A.; Sanderson, D. J.; Zuluaga, L. F.

2017-04-01

The way that faults interact with each other controls fault geometries, displacements and strains. Faults rarely occur individually but as sets or networks, with the arrangement of these faults producing a variety of different fault interactions. Fault interactions are characterised in terms of the following: 1) Geometry - the spatial arrangement of the faults. Interacting faults may or may not be geometrically linked (i.e. physically connected), when fault planes share an intersection line. 2) Kinematics - the displacement distributions of the interacting faults and whether the displacement directions are parallel, perpendicular or oblique to the intersection line. Interacting faults may or may not be kinematically linked, where the displacements, stresses and strains of one fault influences those of the other. 3) Displacement and strain in the interaction zone - whether the faults have the same or opposite displacement directions, and if extension or contraction dominates in the acute bisector between the faults. 4) Chronology - the relative ages of the faults. This characterisation scheme is used to suggest a classification for interacting faults. Different types of interaction are illustrated using metre-scale faults from the Mesozoic rocks of Somerset and examples from the literature.

Magnitude and pattern of Arctic warming governed by the seasonality of radiative forcing.

PubMed

Bintanja, R; Krikken, F

2016-12-02

Observed and projected climate warming is strongest in the Arctic regions, peaking in autumn/winter. Attempts to explain this feature have focused primarily on identifying the associated climate feedbacks, particularly the ice-albedo and lapse-rate feedbacks. Here we use a state-of-the-art global climate model in idealized seasonal forcing simulations to show that Arctic warming (especially in winter) and sea ice decline are particularly sensitive to radiative forcing in spring, during which the energy is effectively 'absorbed' by the ocean (through sea ice melt and ocean warming, amplified by the ice-albedo feedback) and consequently released to the lower atmosphere in autumn and winter, mainly along the sea ice periphery. In contrast, winter radiative forcing causes a more uniform response centered over the Arctic Ocean. This finding suggests that intermodel differences in simulated Arctic (winter) warming can to a considerable degree be attributed to model uncertainties in Arctic radiative fluxes, which peak in summer.

Climatic warming and the future of bison as grazers

NASA Astrophysics Data System (ADS)

Craine, Joseph M.; Towne, E. Gene; Miller, Mary; Fierer, Noah

2015-11-01

Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores.

Warming experiments underpredict plant phenological responses to climate change

USGS Publications Warehouse

Wolkovich, Elizabeth M.; Cook, Benjamin I.; Allen, Jenica M.; Crimmins, Theresa M.; Betancourt, Julio L.; Travers, Steven E.; Pau, Stephanie; Regetz, James; Davies, T. Jonathan; Kraft, Nathan J.B.; Ault, Toby R.; Bolmgren, Kjell; Mazer, Susan J.; McCabe, Gregory J.; McGill, Brian J.; Parmesan, Camille; Salamin, Nicolas; Schwartz, Mark D.; Cleland, Elsa E.

2012-01-01

Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

Warming Experiments Underpredict Plant Phenological Responses to Climate Change

NASA Technical Reports Server (NTRS)

Wolkovich, E. M.; Cook, B. I.; Allen, J. M.; Crimmins, T. M.; Betancourt, J. L.; Travers, S. E.; Pau, S.; Regetz, J.; Davies, T. J.; Kraft, N. J. B.;

Fault recovery characteristics of the fault tolerant multi-processor

NASA Technical Reports Server (NTRS)

Padilla, Peter A.

1990-01-01

The fault handling performance of the fault tolerant multiprocessor (FTMP) was investigated. Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles byzantine or lying faults. It is pointed out that these weak areas in the FTMP's design increase the probability that, for any hardware fault, a good LRU (line replaceable unit) is mistakenly disabled by the fault management software. It is concluded that fault injection can help detect and analyze the behavior of a system in the ultra-reliable regime. Although fault injection testing cannot be exhaustive, it has been demonstrated that it provides a unique capability to unmask problems and to characterize the behavior of a fault-tolerant system.

77 FR 76065 - Endangered and Threatened Wildlife and Plants; Draft Revised Recovery Plan for Kendall Warm...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-26

..., exotic species, grazing, hydrologic changes, invasive plants, pollution, and energy resource exploration... revised recovery plan for the Kendall Warm Springs dace (Rhinichthys osculus thermalis). This species is federally listed as endangered under the Endangered Species Act of 1973, as amended (ESA). The Service...

Identification of geothermal system using 2D audio magnetotelluric method in Telomoyo volcanic area

NASA Astrophysics Data System (ADS)

Romadlon, Arriqo'Fauqi; Niasari, Sintia Windhi

2017-07-01

Geothermal area of Candi Umbul Telomoyo is one of geothermal fields in Indonesia. This geothermal field is located in the Grabag district, Magelang, Central Java. This geothermal field was formed in a volcanic quarter. The main aim in this study is to identify geothermal system at Telomoyo volcanic area through synthetic model analysis. There are surface manifestations such as warm springs and altered rocks. Results of geochemistry study showed reservoir's temperature was 230°C. The Warm spring in Candi Umbul was the outflow zone of the Telomoyo geothermal system. The Telomoyo geothermal system was indicated chloride-bicarbonate type of warm spring. In addition, the results of geological mapping indicate that the dominant fault structure has southwest-northeast orientation. The fault was caused by the volcanic activity of mount Telomoyo. In this research conducted data analysis from synthetics model. It aims to estimate the response of magnetotelluric methods in various models of geothermal systems. In this study, we assumed three models of geothermal system in Candi Umbul-Telomoyo area. From the data analysis it was known that the model 1 and model 2 can be distinguished if the measurements were conducted in a frequency range of 0.01 Hz to 1000 Hz. In response of tipper (Hz) had a small value on all models at all measurement points, so the tipper cannot distinguish between model 1, model 2 and model 3. From this analysis was known that TM mode is more sensitive than TE mode at the resistivity and phase responses.

Establishing native warm season grasses on Eastern Kentucky strip mines

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

Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

1998-12-31

The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomassmore » samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife

Simulated climate-warming increases Coleoptera activity-densities and reduces community diversity in a cereal crop

USDA-ARS?s Scientific Manuscript database

To assess one likely effect of global warming, we experimentally increased the temperature and precipitation of a coleopteran community (mainly Carabidae) of an agro-ecosystem. We simulated climate change on a field of spring wheat by experimentally increasing the temperature by 2°C using infrared h...

Geochemistry and fluxes of volatiles in the Magadi and Natron thermal springs, East African Rift

NASA Astrophysics Data System (ADS)

Lee, H.; Fischer, T. P.; Muirhead, J.; Ebinger, C. J.; Kattenhorn, S. A.; Sharp, Z. D.; Sano, Y.; Takahata, N.

2016-12-01

The Magadi and Natron basin (MNB) is in the earliest stages of continental rifting (<10 Ma) in the East African Rift, and is bounded by numerous normal faults releasing a significant amount of CO2 (4.05 Mt/yr). Although many thermal springs have been observed along fault zones, sources and fluxes of volatiles from these fluids are poorly known. This study reports geochemistry and fluxes of dissolved gases in thermal springs of the MNB (T = 36.8 - 83.5°C and pH = 8.5 - 10.3), including major gas chemistry, d13C-CO2, d15N-N2, and 3He/4He ratios. N2 (< 94.7 vol%) is the most abundant gas, with minor air contamination (mean value of O2 = 1.79 vol%). The majority of CO2 (mean = 11.8 vol%) is dissolved in alkaline waters. Abundant CH4 concentrations (19.3 and 25.1 vol%) are observed only in high temperature (82.3 - 83.5°C) samples. Mean values of Ar and He are 1.75 and 0.59 vol%, respectively. d13C-CO2 (-5.68 to 1.62‰) and CO2/3He (7.24 x 108 - 1.81 x 1011) values show that CO2 originates from both mantle and limestone. d15N-N2 (-1.46 to 0.35‰) and N2/3He (3.92 x 106 - 1.33 x 109) values indicate that the major source of N2 is atmospheric, with a minor input of mantle N2 (fmantle < 22%), except for an anomalous biogenic sample (d15N-N2 = 5.93‰). 3He/4He ratios (0.64 - 4.00 Ra) suggest contributions of radiogenic 4He derived from a crustal source. 4He flux rates (3.64 x 1011 - 3.34 x 1014 atoms/m2 sec) calculated using spring flow rates are much greater than reported mean of continental flux values (4.18x1010 atoms/m2 sec), implying that magma intrusions or widespread normal faulting may help to mobilize crustal 4He in the study area. Total flux values (mol/yr) of CO2, N2, 3He, and 4He are 7.91 x 106, 1.77 x 107, 8.18, and 9.33 x 104, respectively. In particular, the total CO2 flux of springs is 0.01% of the total diffuse CO2 flux reported in the region. Our results reveal an interaction between mantle-derived volatiles and continental crust during early stage

Evaluation of four supervised learning methods for groundwater spring potential mapping in Khalkhal region (Iran) using GIS-based features

NASA Astrophysics Data System (ADS)

Naghibi, Seyed Amir; Moradi Dashtpagerdi, Mostafa

2017-01-01

One important tool for water resources management in arid and semi-arid areas is groundwater potential mapping. In this study, four data-mining models including K-nearest neighbor (KNN), linear discriminant analysis (LDA), multivariate adaptive regression splines (MARS), and quadric discriminant analysis (QDA) were used for groundwater potential mapping to get better and more accurate groundwater potential maps (GPMs). For this purpose, 14 groundwater influence factors were considered, such as altitude, slope angle, slope aspect, plan curvature, profile curvature, slope length, topographic wetness index (TWI), stream power index, distance from rivers, river density, distance from faults, fault density, land use, and lithology. From 842 springs in the study area, in the Khalkhal region of Iran, 70 % (589 springs) were considered for training and 30 % (253 springs) were used as a validation dataset. Then, KNN, LDA, MARS, and QDA models were applied in the R statistical software and the results were mapped as GPMs. Finally, the receiver operating characteristics (ROC) curve was implemented to evaluate the performance of the models. According to the results, the area under the curve of ROCs were calculated as 81.4, 80.5, 79.6, and 79.2 % for MARS, QDA, KNN, and LDA, respectively. So, it can be concluded that the performances of KNN and LDA were acceptable and the performances of MARS and QDA were excellent. Also, the results depicted high contribution of altitude, TWI, slope angle, and fault density, while plan curvature and land use were seen to be the least important factors.

Correlation between the silica concentration and the orifice temperature in the warm springs along the jordan-dead sea rift valley

USGS Publications Warehouse

Levitte, D.; Eckstein, Y.

1978-01-01

Analysis of twenty-one thermal springs emerging along the Jordan-Dead Sea Rift Valley in Israel indicates a very good correlation between the concentration of dissolved silica and the temperature of the spring orifice. Dissolution of quartz was identified as the apparent source of the silica in the water. Application of the silica geothermometer for mixed systems suggests that the springs in the Tiberias Lake Basin are supplied with hot water from deep reservoir (or reservoirs) at a temperature of 115??C (239??F). The same temperature was postulated earlier by the application of the Na-K-Ca hydro-geothermometer to a group of thermal springs in the same basin. The temperature of the reservoir supplying hot brines to the springs emerging along the western shore of the Dead Sea is estimated at 90??C (194??F).

Alteration of fault rocks by CO2-bearing fluids with implications for sequestration

NASA Astrophysics Data System (ADS)

Luetkemeyer, P. B.; Kirschner, D. L.; Solum, J. G.; Naruk, S.

2011-12-01

Carbonates and sulfates commonly occur as primary (diagenetic) pore cements and secondary fluid-mobilized veins within fault zones. Stable isotope analyses of calcite, formation fluid, and fault zone fluids can help elucidate the carbon sources and the extent of fluid-rock interaction within a particular reservoir. Introduction of CO2 bearing fluids into a reservoir/fault system can profoundly affect the overall fluid chemistry of the reservoir/fault system and may lead to the enhancement or degradation of porosity within the fault zone. The extent of precipitation and/or dissolution of minerals within a fault zone can ultimately influence the sealing properties of a fault. The Colorado Plateau contains a number of large carbon dioxide reservoirs some of which leak and some of which do not. Several normal faults within the Paradox Basin (SE Utah) dissect the Green River anticline giving rise to a series of footwall reservoirs with fault-dependent columns. Numerous CO2-charged springs and geysers are associated with these faults. This study seeks to identify regional sources and subsurface migration of CO2 to these reservoirs and the effect(s) faults have on trap performance. Data provided in this study include mineralogical, elemental, and stable isotope data for fault rocks, host rocks, and carbonate veins that come from two localities along one fault that locally sealed CO2. This fault is just tens of meters away from another normal fault that has leaked CO2-charged waters to the land surface for thousands of years. These analyses have been used to determine the source of carbon isotopes from sedimentary derived carbon and deeply sourced CO2. XRF and XRD data taken from several transects across the normal faults are consistent with mechanical mixing and fluid-assisted mass transfer processes within the fault zone. δ13C range from -6% to +10% (PDB); δ18O values range from +15% to +24% (VSMOW). Geochemical modeling software is used to model the alteration

Character and Implications of a Newly Identified Creeping Strand of the San Andreas fault NE of Salton Sea, Southern California

NASA Astrophysics Data System (ADS)

Janecke, S. U.; Markowski, D.

2015-12-01

Valley to join the blind Palm Spring dextral fault- a source of microearthquakes and differential subsidence. The ESS may also continue north parallel to the margin of the Salton Trough or have both a NW and NE branch. The risk of a future large earthquake directly beneath the greater Palm Springs metropolitan area may be larger if the first or last options are correct.

Methane Cycling in a Warming Wetland

NASA Astrophysics Data System (ADS)

Noyce, G. L.; Megonigal, P.; Rich, R.; Kirwan, M. L.; Herbert, E. R.

2017-12-01

Coastal wetlands are global hotspots of carbon (C) storage, but the future of these systems is uncertain. In June 2016, we initiated an in-situ, active, whole-ecosystem warming experiment in the Smithsonian's Global Change Research Wetland to quantify how warming and elevated CO2 affect the stability of coastal wetland soil C pools and contemporary rates of C sequestration. Transects are located in two plant communities, dominated by C3 sedges or C4 grasses. The experiment has a gradient design with air and soil warming treatments ranging from ambient to +5.1 °C and heated plots consistently maintain their target temperature year-round. In April 2017, an elevated CO2 treatment was crossed with temperature in the C3community. Ongoing measurements include soil elevation, C fluxes, porewater chemistry and redox potential, and above- and below-ground growth and biomass. In both years, warming increased methane (CH4) emissions (measured at 3-4 week intervals) from spring through fall at the C3 site, but had little effect on emissions from the C4 site. Winter (Dec-Mar) emissions showed no treatment effect. Stable isotope analysis of dissolved CH4 and DIC also indicated that warming had differing effects on CH4 pathways in the two vegetation communities. To better understand temperature effects on rates of CH4 production and oxidation, 1 m soil cores were collected from control areas of the marsh in summer 2017 and incubated at temperatures ranging from 4 °C to 35 °C. Warming increased CH4 production and oxidation rates in surface samples and oxidation rates in the rooting zone samples from both sites, but temperature responses in deep (1 m) soil samples were minimal. In the surface and rooting zone samples, production rates were also consistently higher in C3 soils compared to C4 soils, but, contrary to our expectations, the temperature response was stronger in the C4 soils. However, oxidation in C3 rooting zone samples did have a strong temperature response. The

Geomorphic expression of strike-slip faults: field observations vs. analog experiments: preliminary results

NASA Astrophysics Data System (ADS)

Hsieh, S. Y.; Neubauer, F.; Genser, J.

2012-04-01

The aim of this project is to study the surface expression of strike-slip faults with main aim to find rules how these structures can be extrapolated to depth. In the first step, several basic properties of the fault architecture are in focus: (1) Is it possible to define the fault architecture by studying surface structures of the damage zone vs. the fault core, particularly the width of the damage zone? (2) Which second order structures define the damage zone of strike-slip faults, and how relate these to such reported in basement fault strike-slip analog experiments? (3) Beside classical fault bend structures, is there a systematic along-strike variation of the damage zone width and to which properties relates the variation of the damage zone width. We study the above mentioned properties on the dextral Altyn fault, which is one of the largest strike-slip on Earth with the advantage to have developed in a fully arid climate. The Altyn fault includes a ca. 250 to 600 m wide fault valley, usually with the trace of actual fault in its center. The fault valley is confined by basement highs, from which alluvial fans develop towards the center of the fault valley. The active fault trace is marked by small scale pressure ridges and offset of alluvial fans. The fault valley confining basement highs are several kilometer long and ca. 0.5 to 1 km wide and confined by rotated dextral anti-Riedel faults and internally structured by a regular fracture pattern. Dextral anti-Riedel faults are often cut by Riedel faults. Consequently, the Altyn fault comprises a several km wide damage zone. The fault core zone is a barrier to fluid flow, and the few springs of the region are located on the margin of the fault valley implying the fractured basement highs as the reservoir. Consequently, the southern Silk Road was using the Altyn fault valley. The preliminary data show that two or more orders of structures exist. Small-scale develop during a single earthquake. These finally

How does the dengue vector mosquito Aedes albopictus respond to global warming?

PubMed

Jia, Pengfei; Chen, Xiang; Chen, Jin; Lu, Liang; Liu, Qiyong; Tan, Xiaoyue

2017-03-11

Global warming has a marked influence on the life cycle of epidemic vectors as well as their interactions with human beings. The Aedes albopictus mosquito as the vector of dengue fever surged exponentially in the last decade, raising ecological and epistemological concerns of how climate change altered its growth rate and population dynamics. As the global warming pattern is considerably uneven across four seasons, with a confirmed stronger effect in winter, an emerging need arises as to exploring how the seasonal warming effects influence the annual development of Ae. albopictus. The model consolidates a 35-year climate dataset and designs fifteen warming patterns that increase the temperature of selected seasons. Based on a recently developed mechanistic population model of Ae. albopictus, the model simulates the thermal reaction of blood-fed adults by systematically increasing the temperature from 0.5 to 5 °C at an interval of 0.5 °C in each warming pattern. The results show the warming effects are different across seasons. The warming effects in spring and winter facilitate the development of the species by shortening the diapause period. The warming effect in summer is primarily negative by inhibiting mosquito development. The warming effect in autumn is considerably mixed. However, these warming effects cannot carry over to the following year, possibly due to the fact that under the extreme weather in winter the mosquito fully ceases from development and survives in terms of diapause eggs. As the historical pattern of global warming manifests seasonal fluctuations, this study provides corroborating and previously ignored evidence of how such seasonality affects the mosquito development. Understanding this short-term temperature-driven mechanism as one chain of the transmission events is critical to refining the thermal reaction norms of the epidemic vector under global warming as well as developing effective mosquito prevention and control strategies.

Methods to enhance seismic faults and construct fault surfaces

NASA Astrophysics Data System (ADS)

Wu, Xinming; Zhu, Zhihui

2017-10-01

Faults are often apparent as reflector discontinuities in a seismic volume. Numerous types of fault attributes have been proposed to highlight fault positions from a seismic volume by measuring reflection discontinuities. These attribute volumes, however, can be sensitive to noise and stratigraphic features that are also apparent as discontinuities in a seismic volume. We propose a matched filtering method to enhance a precomputed fault attribute volume, and simultaneously estimate fault strikes and dips. In this method, a set of efficient 2D exponential filters, oriented by all possible combinations of strike and dip angles, are applied to the input attribute volume to find the maximum filtering responses at all samples in the volume. These maximum filtering responses are recorded to obtain the enhanced fault attribute volume while the corresponding strike and dip angles, that yield the maximum filtering responses, are recoded to obtain volumes of fault strikes and dips. By doing this, we assume that a fault surface is locally planar, and a 2D smoothing filter will yield a maximum response if the smoothing plane coincides with a local fault plane. With the enhanced fault attribute volume and the estimated fault strike and dip volumes, we then compute oriented fault samples on the ridges of the enhanced fault attribute volume, and each sample is oriented by the estimated fault strike and dip. Fault surfaces can be constructed by directly linking the oriented fault samples with consistent fault strikes and dips. For complicated cases with missing fault samples and noisy samples, we further propose to use a perceptual grouping method to infer fault surfaces that reasonably fit the positions and orientations of the fault samples. We apply these methods to 3D synthetic and real examples and successfully extract multiple intersecting fault surfaces and complete fault surfaces without holes.

Abnormal fault-recovery characteristics of the fault-tolerant multiprocessor uncovered using a new fault-injection methodology

NASA Technical Reports Server (NTRS)

Padilla, Peter A.

1991-01-01

An investigation was made in AIRLAB of the fault handling performance of the Fault Tolerant MultiProcessor (FTMP). Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once in every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles Byzantine or lying faults. Byzantine faults behave such that the faulted unit points to a working unit as the source of errors. The design's problems involve: (1) the design and interface between the simplex error detection hardware and the error processing software, (2) the functional capabilities of the FTMP system bus, and (3) the communication requirements of a multiprocessor architecture. These weak areas in the FTMP's design increase the probability that, for any hardware fault, a good line replacement unit (LRU) is mistakenly disabled by the fault management software.

Impact of climate warming on upper layer of the Bering Sea

NASA Astrophysics Data System (ADS)

Lee, Hyun-Chul; Delworth, Thomas L.; Rosati, Anthony; Zhang, Rong; Anderson, Whit G.; Zeng, Fanrong; Stock, Charles A.; Gnanadesikan, Anand; Dixon, Keith W.; Griffies, Stephen M.

2013-01-01

The impact of climate warming on the upper layer of the Bering Sea is investigated by using a high-resolution coupled global climate model. The model is forced by increasing atmospheric CO2 at a rate of 1% per year until CO2 reaches double its initial value (after 70 years), after which it is held constant. In response to this forcing, the upper layer of the Bering Sea warms by about 2°C in the southeastern shelf and by a little more than 1°C in the western basin. The wintertime ventilation to the permanent thermocline weakens in the western Bering Sea. After CO2 doubling, the southeastern shelf of the Bering Sea becomes almost ice-free in March, and the stratification of the upper layer strengthens in May and June. Changes of physical condition due to the climate warming would impact the pre-condition of spring bio-productivity in the southeastern shelf.

Climate model assessment of changes in winter-spring streamflow timing over North America

USGS Publications Warehouse

Kam, Jonghun; Knutson, Thomas R.; Milly, Paul C. D.

2018-01-01

Over regions where snow-melt runoff substantially contributes to winter-spring streamflows, warming can accelerate snow melt and reduce dry-season streamflows. However, conclusive detection of changes and attribution to anthropogenic forcing is hindered by brevity of observational records, model uncertainty, and uncertainty concerning internal variability. In this study, a detection/attribution of changes in mid-latitude North American winter-spring streamflow timing is examined using nine global climate models under multiple forcing scenarios. In this study, robustness across models, start/end dates for trends, and assumptions about internal variability is evaluated. Marginal evidence for an emerging detectable anthropogenic influence (according to four or five of nine models) is found in the north-central U.S., where winter-spring streamflows have been coming earlier. Weaker indications of detectable anthropogenic influence (three of nine models) are found in the mountainous western U.S./southwestern Canada and in extreme northeastern U.S./Canadian Maritimes. In the former region, a recent shift toward later streamflows has rendered the full-record trend toward earlier streamflows only marginally significant, with possible implications for previously published climate change detection findings for streamflow timing in this region. In the latter region, no forced model shows as large a shift toward earlier streamflow timing as the detectable observed shift. In other (including warm, snow-free) regions, observed trends are typically not detectable, although in the U.S. central plains we find detectable delays in streamflow, which are inconsistent with forced model experiments.

Mountain building on Io driven by deep faulting

USGS Publications Warehouse

Bland, Michael T.; McKinnon, William B

2016-01-01

Jupiter’s volcanic moon Io possesses some of the highest relief in the Solar System: massive, isolated mountain blocks that tower up to 17 km above the surrounding plains. These mountains are likely to result from pervasive compressive stresses induced by subsidence of the surface beneath the near-continual emplacement of volcanic material. The stress state that results from subsidence and warming of Io’s lithosphere has been investigated in detail1, 2, 3, 4; however, the mechanism of orogenesis itself and its effect on regional tectonism and volcanism has not been firmly established. Here we present viscoelastic–plastic finite element simulations demonstrating that Io’s mountains form along deep-seated thrust faults that initiate at the base of the lithosphere and propagate upward. We show that faulting fundamentally alters the stress state of Io’s lithosphere by relieving the large volcanism-induced subsidence stresses. Notably, in the upper portion of the lithosphere, stresses become tensile (near-zero differential stress). A number of processes are therefore altered post-faulting, including magma transport through the lithosphere, interactions with tidal stresses and potentially the localization of mountain formation by thermoelastic stresses. We conclude that Io’s mountains form by a unique orogenic mechanism, compared with tectonic processes operating elsewhere in the Solar System.

Geo-electrical and geological strikes of the Mount Lamongan geothermal area, East Java, Indonesia – preliminary results

NASA Astrophysics Data System (ADS)

Nugraheni, L. R.; Niasari, S. W.; Nukman, M.

2018-04-01

Geothermal manifestations located in the Tiris, Mount Lamongan, Probolinggo, consist of warm springs. These warm springs have temperature from 35° until 45°C. Tiris fault has NW-SE dominant orientation, similar to some lineaments of maars and cinder cones around Mount Lamongan. The Mount Lamongan geothermal area is situated between Bromo and Argapura volcanoes. This study aims to map the geo-electrical and geological strikes in the study area. Phase tensor analysis has been performed in this study to determine geo-electrical strike of study area. Geological field campaign has been conducted to measure geological strikes. Then, orientation of geo-electrical strike was compared to geological strike. The result presents that the regional geological strike of study area is NW-SE while the orientation of geo-electrical strike is N-S.

Advective, Diffusive and Eruptive Leakage of CO2 and Brine within Fault Zone

NASA Astrophysics Data System (ADS)

Jung, N. H.; Han, W. S.

2014-12-01

This study investigated a natural analogue for CO2 leakage near the Green River, Utah, aiming to understand the influence of various factors on CO2 leakage and to reliably predict underground CO2 behavior after injection for geologic CO2 sequestration. Advective, diffusive, and eruptive characteristics of CO2 leakage were assessed via a soil CO2 flux survey and numerical modeling. The field results show anomalous CO2 fluxes (> 10 g m-2 d-1) along the faults, particularly adjacent to CO2-driven cold springs and geysers (e.g., 36,259 g m-2 d-1 at Crystal Geyser), ancient travertines (e.g., 5,917 g m-2 d-1), joint zones in sandstone (e.g., 120 g m-2 d-1), and brine discharge zones (e.g., 5,515 g m-2 d-1). Combined to similar isotopic ratios of gas and progressive evolution of brine chemistry at springs and geysers, a gradual decrease of soil CO2 flux from the Little Grand Wash (LGW; ~36,259 g m-2 d-1) to Salt Wash (SW; ~1,428 g m-2 d-1) fault zones reveals the same CO2 origin and potential southward transport of CO2 over 10-20 km. The numerical simulations overtly exhibit lateral transport of free CO2 and CO2-rich brine from the LGW to SW fault zones through the regional aquifers (e.g., Entrada, Navajo, Kayenta, Wingate, White Rim). CO2 travels predominantly as an aqueous phase (Xco2=~0.045) as previously suggested, giving rise to the convective instability that further accelerates CO2 dissolution. While the buoyant free CO2 always tends to ascend, a fraction of dense CO2-rich brine flows laterally into the aquifer and mixes with the formation fluids during upward migration along the fault. The fault always enhances advective CO2 transport regardless of its permeability (k). However, only the low-k fault scenario engenders development of CO2 anticlinal trap within the shallow aquifers (Entrada and Navajo), concentrating high CO­­­2 fluxes (~1,273 g m-2 d-1) within the northern footwall of the LGW fault similar to the field. Moreover, eruptive CO2 leakage at a well

Heat flow in western Virginia and a model for the origin of thermal springs in the folded Appalachians

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

Perry, L.D.; Costain, J.K.; Geiser, P.A.

1979-11-10

Five new heat flow values in the Blue Ridge (37/sup 0/02'N, 80/sup 0/12'W), Valley and Ridge (38/sup 0/00'N, 79/sup 0/50'W; 37/sup 0/54'N, 79/sup 0/54'W; 38/sup 0/14'N, 79/sup 0/49'W), and Alleghany Plateau (37/sup 0/12'N, 82/sup 0/06'W) provinces of Virginia are 36.3 +- 1.3mW/m/sup 2/, 317 +- 20mW/m/sup 2/, 48.2 +- 0.3mW/m/sup 2/, 49.5 +- 1.5mW/m/sup 2/, and 55.8 +- 1.7mW/m/sup 2/, respectively. The value of 36.3mW/m/sup 2/ in the Blue Ridge agrees with values predicted by the contour map of Sass et al. (1976) for this part of the eastern United States; the values of 49.5 and 48.3mW/m/sup 2/ in themore » Valley and Ridge province do not. The high value of 317 +- 20mW/m/sup 2/ at Hot Springs, Virginia, is the result of convection along a fault zone and is not regionally representative. The value of 48.3mW/m/sup 2/ determined at a site about 8 km southwest of Hot Springs, Virginia, is regionally representative of the heat flux. New data support a model of moderately deep circulation of meteoric water entering near-vertical sedimentary beds at relatively high topographic elevations and circulating downward via bedding plane permeability and fractures within Silurian quartzites and/or adjacent carbonate units. The moderately deep circulation is then intersected by vertical transverse linear fracture zones along which the water rises. All of the warm springs are located adjacent to topographic gaps which have developed along zones of weakness associated with the transverse fracture zones.« less

Fault-controlled advective, diffusive, and eruptive CO 2 leakage from natural reservoirs in the Colorado Plateau, East-Central Utah

NASA Astrophysics Data System (ADS)

Jung, Na-Hyun

This study investigated a natural analogue for CO2 leakage near Green River, Utah, aiming to understand the influence of various factors on CO2 leakage and to reliably predict underground CO2 behavior after injection for geologic CO2 sequestration. Advective, diffusive, and eruptive characteristics of CO2 leakage were assessed via a soil CO2 flux survey and numerical modeling. The field results show anomalous CO2 fluxes (> 10 g m-2 d-1 ) along the faults, particularly adjacent to CO2-driven cold springs and geysers (e.g., 36,259 g m-2 d-1 at Crystal Geyser), ancient travertines (e.g., 5,917 g m-2 d-1), joint zones in sandstone (e.g., 120 g m-2 d-1), and brine discharge zones (e.g., 5,515 g m-2 d-1). Combined with similar isotopic ratios of gas and progressive evolution of brine chemistry at springs and geysers, a gradual decrease of soil CO2 flux from the Little Grand Wash (LGW; ~36,259 g m -2 d-1) to Salt Wash (SW; ~1,428 g m-2 d-1) fault zones reveals the same CO2 origin and potential southward transport of CO2 over 10-20 km. The numerical simulations exhibit lateral transport of free CO2 and CO2-rich brine from the LGW to SW fault zones through the regional aquifers (e.g., Entrada, Navajo, Kayenta, Wingate, White Rim). CO2 travels predominantly as an aqueous phase (XCO2=~0.045) as previously suggested, giving rise to the convective instability that further accelerates CO2 dissolution. While the buoyant free CO2 always tends to ascend, a fraction of dense CO2-rich brine flows laterally into the aquifer and mixes with the formation fluids during upward migration along the fault. The fault always enhances advective CO2 transport regardless of its permeability (k). However, only low-k fault prevents unconditional upright migration of CO2 and induces fault-parallel movement, feeding the northern aquifers with more CO2. Low-k fault also impedes lateral southward fluid flow from the northern aquifers, developing anticlinal CO2 traps at shallow depths (<300 m). The

Evolution of the Puente Hills Thrust Fault

NASA Astrophysics Data System (ADS)

Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

2013-12-01

This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

Dynamics behind warming of the southeastern Arabian Sea and its interruption based on in situ measurements

NASA Astrophysics Data System (ADS)

Mathew, Simi; Natesan, Usha; Latha, Ganesan; Venkatesan, Ramasamy

2018-05-01

A study of the inter-annual variability of the warming of the southeastern Arabian Sea (SEAS) during the spring transition months was carried out from 2013 to 2015 based on in situ data from moored buoys. An attempt was made to identify the roles of the different variables in the warming of the SEAS (e.g., net heat flux, advection, entrainment, and thickness of the barrier layer during the previous northeast monsoon season). The intense freshening of the SEAS (approximately 2 PSU) occurring in each December, together with the presence of a downwelling Rossby wave, supports the formation of a thick barrier layer during the northeast monsoon season. It is known that the barrier layer thickness, varying each year, plays a major role in the spring warming of the SEAS. Interestingly, an anomalously thick barrier layer occurred during the northeast monsoon season of 2012-2013. However, the highest sea surface temperature (31 °C) was recorded during the last week of April 2015, while the lowest sea surface temperature (29.7 °C) was recorded during the last week of May 2013. The mixed layer heat budget analysis during the spring transition months proved that the intense warming has been mainly supported by the net heat flux, not by other factors like advection and entrainment. The inter-annual variability analysis of the net heat flux and its components, averaged over a box region of the SEAS, showed a substantial latent heat flux release and a reduction in net shortwave radiation in 2013. Both factors contributed to the negative net heat flux. Strong breaks in the warming were also observed in May due to the entrainment of cold sub-surface waters. These events are associated with the cyclonic eddy persisting over the SEAS during the same time. The entrainment term, favoring the cooling, was stronger in 2015 than that in 2013 and 2014. The surface temperatures measured in 2013 were lower than those in 2014 and 2015 despite the presence of a thick barrier layer. The

Adaptive Fault-Tolerant Control of Uncertain Nonlinear Large-Scale Systems With Unknown Dead Zone.

PubMed

Chen, Mou; Tao, Gang

2016-08-01

In this paper, an adaptive neural fault-tolerant control scheme is proposed and analyzed for a class of uncertain nonlinear large-scale systems with unknown dead zone and external disturbances. To tackle the unknown nonlinear interaction functions in the large-scale system, the radial basis function neural network (RBFNN) is employed to approximate them. To further handle the unknown approximation errors and the effects of the unknown dead zone and external disturbances, integrated as the compounded disturbances, the corresponding disturbance observers are developed for their estimations. Based on the outputs of the RBFNN and the disturbance observer, the adaptive neural fault-tolerant control scheme is designed for uncertain nonlinear large-scale systems by using a decentralized backstepping technique. The closed-loop stability of the adaptive control system is rigorously proved via Lyapunov analysis and the satisfactory tracking performance is achieved under the integrated effects of unknown dead zone, actuator fault, and unknown external disturbances. Simulation results of a mass-spring-damper system are given to illustrate the effectiveness of the proposed adaptive neural fault-tolerant control scheme for uncertain nonlinear large-scale systems.

Secular spring rainfall variability at local scale over Ethiopia: trend and associated dynamics

NASA Astrophysics Data System (ADS)

Tsidu, Gizaw Mengistu

2017-10-01

Spring rainfall secular variability is studied using observations, reanalysis, and model simulations. The joint coherent spatio-temporal secular variability of gridded monthly gauge rainfall over Ethiopia, ERA-Interim atmospheric variables and sea surface temperature (SST) from Hadley Centre Sea Ice and SST (HadISST) data set is extracted using multi-taper method singular value decomposition (MTM-SVD). The contemporaneous associations are further examined using partial Granger causality to determine presence of causal linkage between any of the climate variables. This analysis reveals that only the northwestern Indian Ocean secular SST anomaly has direct causal links with spring rainfall over Ethiopia and mean sea level pressure (MSLP) over Africa inspite of the strong secular covariance of spring rainfall, SST in parts of subtropical Pacific, Atlantic, Indian Ocean and MSLP. High secular rainfall variance and statistically significant linear trend show consistently that there is a massive decline in spring rain over southern Ethiopia. This happened concurrently with significant buildup of MSLP over East Africa, northeastern Africa including parts of the Arabian Peninsula, some parts of central Africa and SST warming over all ocean basins with the exception of the ENSO regions. The east-west pressure gradient in response to the Indian Ocean warming led to secular southeasterly winds over the Arabian Sea, easterly over central Africa and equatorial Atlantic. These flows weakened climatological northeasterly flow over the Arabian Sea and southwesterly flow over equatorial Atlantic and Congo basins which supply moisture into the eastern Africa regions in spring. The secular divergent flow at low level is concurrent with upper level convergence due to the easterly secular anomalous flow. The mechanisms through which the northwestern Indian Ocean secular SST anomaly modulates rainfall are further explored in the context of East Africa using a simplified atmospheric

Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year.

PubMed

Steig, Eric J; Schneider, David P; Rutherford, Scott D; Mann, Michael E; Comiso, Josefino C; Shindell, Drew T

2009-01-22

Assessments of Antarctic temperature change have emphasized the contrast between strong warming of the Antarctic Peninsula and slight cooling of the Antarctic continental interior in recent decades. This pattern of temperature change has been attributed to the increased strength of the circumpolar westerlies, largely in response to changes in stratospheric ozone. This picture, however, is substantially incomplete owing to the sparseness and short duration of the observations. Here we show that significant warming extends well beyond the Antarctic Peninsula to cover most of West Antarctica, an area of warming much larger than previously reported. West Antarctic warming exceeds 0.1 degrees C per decade over the past 50 years, and is strongest in winter and spring. Although this is partly offset by autumn cooling in East Antarctica, the continent-wide average near-surface temperature trend is positive. Simulations using a general circulation model reproduce the essential features of the spatial pattern and the long-term trend, and we suggest that neither can be attributed directly to increases in the strength of the westerlies. Instead, regional changes in atmospheric circulation and associated changes in sea surface temperature and sea ice are required to explain the enhanced warming in West Antarctica.

Overwintering temperature and body condition shift emergence dates of spring-emerging solitary bees.

PubMed

Schenk, Mariela; Mitesser, Oliver; Hovestadt, Thomas; Holzschuh, Andrea

2018-01-01

Solitary bees in seasonal environments must align their life-cycles with favorable environmental conditions and resources; the timing of their emergence is highly fitness relevant. In several bee species, overwintering temperature influences both emergence date and body weight at emergence. High variability in emergence dates among specimens overwintering at the same temperatures suggests that the timing of emergence also depends on individual body conditions. However, possible causes for this variability, such as individual differences in body size or weight, have been rarely studied. In a climate chamber experiment using two spring-emerging mason bees ( Osmia cornuta and O. bicornis ), we investigated the relationship between temperature, emergence date, body weight, and body size, the last of which is not affected by overwintering temperature. Our study showed that body weight declined during hibernation more strongly in warm than in cold overwintering temperatures. Although bees emerged earlier in warm than in cold overwintering temperatures, at the time of emergence, bees in warm overwintering temperatures had lower body weights than bees in cold overwintering temperatures (exception of male O. cornuta ). Among specimens that experienced the same overwintering temperatures, small and light bees emerged later than their larger and heavier conspecifics. Using a simple mechanistic model we demonstrated that spring-emerging solitary bees use a strategic approach and emerge at a date that is most promising for their individual fitness expectations. Our results suggest that warmer overwintering temperatures reduce bee fitness by causing a decrease in body weight at emergence. We showed furthermore that in order to adjust their emergence dates, bees use not only temperature but also their individual body condition as triggers. This may explain differing responses to climate warming within and among bee populations and may have consequences for bee-plant interactions

Influence of fault trend, fault bends, and fault convergence on shallow structure, geomorphology, and hazards, Hosgri strike-slip fault, offshore central California

NASA Astrophysics Data System (ADS)

Johnson, S. Y.; Watt, J. T.; Hartwell, S. R.

2012-12-01

We mapped a ~94-km-long portion of the right-lateral Hosgri Fault Zone from Point Sal to Piedras Blancas in offshore central California using high-resolution seismic reflection profiles, marine magnetic data, and multibeam bathymetry. The database includes 121 seismic profiles across the fault zone and is perhaps the most comprehensive reported survey of the shallow structure of an active strike-slip fault. These data document the location, length, and near-surface continuity of multiple fault strands, highlight fault-zone heterogeneity, and demonstrate the importance of fault trend, fault bends, and fault convergences in the development of shallow structure and tectonic geomorphology. The Hosgri Fault Zone is continuous through the study area passing through a broad arc in which fault trend changes from about 338° to 328° from south to north. The southern ~40 km of the fault zone in this area is more extensional, resulting in accommodation space that is filled by deltaic sediments of the Santa Maria River. The central ~24 km of the fault zone is characterized by oblique convergence of the Hosgri Fault Zone with the more northwest-trending Los Osos and Shoreline Faults. Convergence between these faults has resulted in the formation of local restraining and releasing fault bends, transpressive uplifts, and transtensional basins of varying size and morphology. We present a hypothesis that links development of a paired fault bend to indenting and bulging of the Hosgri Fault by a strong crustal block translated to the northwest along the Shoreline Fault. Two diverging Hosgri Fault strands bounding a central uplifted block characterize the northern ~30 km of the Hosgri Fault in this area. The eastern Hosgri strand passes through releasing and restraining bends; the releasing bend is the primary control on development of an elongate, asymmetric, "Lazy Z" sedimentary basin. The western strand of the Hosgri Fault Zone passes through a significant restraining bend and

Net carbon uptake has increased through warming-induced changes in temperate forest phenology

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

Keenan, Trevor; Gray, Josh; Friedl, Mark

2014-01-01

The timing of phenological events exerts a strong control over ecosystem function and leads to multiple feedbacks to the climate system1. Phenology is inherently sensitive to temperature (though the exact sensitivity is disputed2) and recent warming is reported to have led to earlier spring, later autumn3,4 and increased vegetation activity5,6. Such greening could be expected to enhance ecosystem carbon uptake7,8, though reports also suggest decreased uptake for boreal forests4,9. Here we assess changes in phenology of temperate forests over the eastern US during the past two decades, and quantify the resulting changes in forest carbon storage. We combine long-term groundmore » observations of phenology, satellite indices, and ecosystem-scale carbon dioxide flux measurements, along with 18 terrestrial biosphere models. We observe a strong trend of earlier spring and later autumn. In contrast to previous suggestions4,9 we show that carbon uptake through photosynthesis increased considerably more than carbon release through respiration for both an earlier spring and later autumn. The terrestrial biosphere models tested misrepresent the temperature sensitivity of phenology, and thus the effect on carbon uptake. Our analysis of the temperature-phenology-carbon coupling suggests a current and possible future enhancement of forest carbon uptake due to changes in phenology. This constitutes a negative feedback to climate change, and is serving to slow the rate of warming.« less

FTAPE: A fault injection tool to measure fault tolerance

NASA Technical Reports Server (NTRS)

Tsai, Timothy K.; Iyer, Ravishankar K.

1995-01-01

The paper introduces FTAPE (Fault Tolerance And Performance Evaluator), a tool that can be used to compare fault-tolerant computers. The tool combines system-wide fault injection with a controllable workload. A workload generator is used to create high stress conditions for the machine. Faults are injected based on this workload activity in order to ensure a high level of fault propagation. The errors/fault ratio and performance degradation are presented as measures of fault tolerance.

Fault compaction and overpressured faults: results from a 3-D model of a ductile fault zone

NASA Astrophysics Data System (ADS)

Fitzenz, D. D.; Miller, S. A.

2003-10-01

A model of a ductile fault zone is incorporated into a forward 3-D earthquake model to better constrain fault-zone hydraulics. The conceptual framework of the model fault zone was chosen such that two distinct parts are recognized. The fault core, characterized by a relatively low permeability, is composed of a coseismic fault surface embedded in a visco-elastic volume that can creep and compact. The fault core is surrounded by, and mostly sealed from, a high permeability damaged zone. The model fault properties correspond explicitly to those of the coseismic fault core. Porosity and pore pressure evolve to account for the viscous compaction of the fault core, while stresses evolve in response to the applied tectonic loading and to shear creep of the fault itself. A small diffusive leakage is allowed in and out of the fault zone. Coseismically, porosity is created to account for frictional dilatancy. We show in the case of a 3-D fault model with no in-plane flow and constant fluid compressibility, pore pressures do not drop to hydrostatic levels after a seismic rupture, leading to an overpressured weak fault. Since pore pressure plays a key role in the fault behaviour, we investigate coseismic hydraulic property changes. In the full 3-D model, pore pressures vary instantaneously by the poroelastic effect during the propagation of the rupture. Once the stress state stabilizes, pore pressures are incrementally redistributed in the failed patch. We show that the significant effect of pressure-dependent fluid compressibility in the no in-plane flow case becomes a secondary effect when the other spatial dimensions are considered because in-plane flow with a near-lithostatically pressured neighbourhood equilibrates at a pressure much higher than hydrostatic levels, forming persistent high-pressure fluid compartments. If the observed faults are not all overpressured and weak, other mechanisms, not included in this model, must be at work in nature, which need to be

The source of anomalous radioactivity in the springs bordering the Sea of Galilee, Israel.

PubMed

Ilani, S; Minster, T; Kronfeld, J; Even, O

2006-01-01

Situated within the Jordan Rift Valley, along the shores of Lake Kinneret (Sea of Galilee) which serves as the national water reservoir of Israel, are saline hot springs that are notable for their enrichment in radon and radium. Though the anomalous radioactivity has been known for almost half a century, the source of the radioactive anomalies has been a subject of conjecture. Radiometric analysis of a rock core drilled through Mt. Arbel, situated to the west of the lake, reveals that the oil shale sequence of the Senonian En Zetim and Ghareb formations is strikingly deficient in radium. Mt. Arbel has been cut by Rift Valley related faults that serve as conduits for ascending brines. The organic matter enriched sequence is encountered in the subsurface at elevations lower than the water level of the nearby radioactive enriched hot springs. It is thus concluded that hot ascending brines underlying the lake flush through the organic matter enriched sequence and remove a substantial percentage of 226Ra from the uranium enriched organic material, before draining to the outlets of the springs. Saline springs that are in contact with organic matter enriched sequence show excess of radium and radon, while fresh water springs in the same stratigraphic position show only excess of radon.

A Phenological Timetable of Oak Growth under Experimental Drought and Air Warming

PubMed Central

Kuster, Thomas M.; Dobbertin, Matthias; Günthardt-Goerg, Madeleine S.; Schaub, Marcus; Arend, Matthias

2014-01-01

Climate change is expected to increase temperature and decrease summer precipitation in Central Europe. Little is known about how warming and drought will affect phenological patterns of oaks, which are considered to possess excellent adaptability to these climatic changes. Here, we investigated bud burst and intra-annual shoot growth of Quercus robur, Q. petraea and Q. pubescens grown on two different forest soils and exposed to air warming and drought. Phenological development was assessed over the course of three growing seasons. Warming advanced bud burst by 1–3 days °C−1 and led to an earlier start of intra-annual shoot growth. Despite this phenological shift, total time span of annual growth and shoot biomass were not affected. Drought changed the frequency and intensity of intra-annual shoot growth and advanced bud burst in the subsequent spring of a severe summer drought by 1–2 days. After re-wetting, shoot growth recovered within a few days, demonstrating the superior drought tolerance of this tree genus. Our findings show that phenological patterns of oaks are modified by warming and drought but also suggest that ontogenetic factors and/or limitations of water and nutrients counteract warming effects on the biomass and the entire span of annual shoot growth. PMID:24586988

Fault tolerant system with imperfect coverage, reboot and server vacation

NASA Astrophysics Data System (ADS)

Jain, Madhu; Meena, Rakesh Kumar

2017-06-01

This study is concerned with the performance modeling of a fault tolerant system consisting of operating units supported by a combination of warm and cold spares. The on-line as well as warm standby units are subject to failures and are send for the repair to a repair facility having single repairman which is prone to failure. If the failed unit is not detected, the system enters into an unsafe state from which it is cleared by the reboot and recovery action. The server is allowed to go for vacation if there is no failed unit present in the system. Markov model is developed to obtain the transient probabilities associated with the system states. Runge-Kutta method is used to evaluate the system state probabilities and queueing measures. To explore the sensitivity and cost associated with the system, numerical simulation is conducted.

Response of faults to climate-driven changes in ice and water volumes on Earth's surface.

PubMed

Hampel, Andrea; Hetzel, Ralf; Maniatis, Georgios

2010-05-28

Numerical models including one or more faults in a rheologically stratified lithosphere show that climate-induced variations in ice and water volumes on Earth's surface considerably affect the slip evolution of both thrust and normal faults. In general, the slip rate and hence the seismicity of a fault decreases during loading and increases during unloading. Here, we present several case studies to show that a postglacial slip rate increase occurred on faults worldwide in regions where ice caps and lakes decayed at the end of the last glaciation. Of note is that the postglacial amplification of seismicity was not restricted to the areas beneath the large Laurentide and Fennoscandian ice sheets but also occurred in regions affected by smaller ice caps or lakes, e.g. the Basin-and-Range Province. Our results do not only have important consequences for the interpretation of palaeoseismological records from faults in these regions but also for the evaluation of the future seismicity in regions currently affected by deglaciation like Greenland and Antarctica: shrinkage of the modern ice sheets owing to global warming may ultimately lead to an increase in earthquake frequency in these regions.

Intermittent spring flooding of agricultural fields will increase net global-warming potential of greenhouse gas fluxes

NASA Astrophysics Data System (ADS)

Paul, R. F.; Smyth, E. M.; Smith, C. M.; Kantola, I. B.; Krichels, A.; Yang, W. H.; DeLucia, E. H.

2014-12-01

The U.S. Corn Belt is currently a net source of carbon dioxide and nitrous dioxide to the atmosphere but is also a weak sink for methane. Climate change is projected to increase the frequency and duration of spring precipitation in the North American Midwest, resulting in intermittent flooding and ponding in agricultural fields. Inundation changes the greenhouse gas (GHG) fluxes of the soil, especially by promoting methanogenesis under anoxic conditions. DNA and 16S cDNA sequencing results of earlier, similar experiments confirmed the presence of methanogens in soil samples, albeit in low abundance (representing <0.01% of reads per sample). We installed collars into bare ground of a central Illinois research field to experiment with flooding conditions and observe changes in gas fluxes, microbial community, and soil chemistry. We established three treatments of five replicates—control, continuously flooded, and intermittently flooded—each with separate collars for gas flux measurements, soil sample collection, and soil probe measurements. A drip irrigation system flooded the headspaces of the collars to produce flooding events. The continuously flooded collars were maintained in a flooded condition for the duration of the experiment, and the intermittently flooded collars were flooded for 72 hours per flooding event and then kept dry for at least 5 days before the next flooding event. We measured net concentrations of N2O, CH4, and CO2 in situ using a static chamber connected to a cavity ringdown spectrometer. We found that the periodicity of wetting and drying events induces hysteresis effects that push GHG shifts to occur rapidly (< 1 hr). Integrating fluxes across the period of the experiment, the intermittently flooded collars showed 88.7% higher global-warming potential of GHG fluxes at the 100-year horizon versus control, with most of change driven by increased net CO2 flux (87.1% higher) and net methane flux (29 times higher). These data indicate that

Seismicity preliminary results in a geothermal and volcano activity area: study case Liquiñe-Ofqui fault system in Southern Andes, Chile

NASA Astrophysics Data System (ADS)

Estay, N. P.; Yáñez Morroni, G.; Crempien, J. G. F.; Roquer, T.

2017-12-01

Fluid transport through the crust takes place in domains with high permeability. For this reason, fault damage zones are a main feature where fluids may circulate unimpeded, since they have much larger permeability than normal country rocks. With the location of earthquakes, it is possible to infer fault geometry and stress field of the crust, therefore we can determine potential places where fluid circualtion is taking place. With that purpose, we installed a seismic network in an active volcanic-geothermal system, the Liquiñe-Ofqui Fault System (LOFS), located in Puyuhuapi, Southern Andes (44°-45°S). This allowed to link epicentral seismicity, focal mechanisms and surface expression of fluid circulation (hot-springs and volcanos). The LOFS is composed by two NS-striking dextral master faults, and several secondary NE-striking dextral and normal faults. Surface manifestation of fluid circulation in Puyuhuapi area are: 1) six hot-springs, most of them spatially associated with different mapped faults; 2) seven minor eruptive centers aligned over a 10-km-along one of the master NS-striking fault, and; 3) the Melimouyu strato-volcano without any spatial relationship with mapped faults. The network consists of 6 short period seismometers (S31f-2.0a sensor of IESE, with natural frequency of 2Hz), that were installed between July 2016 and August 2017; also 4 permanent broad-band seismometers (Guralp 6TD/ CD 24 sensor) which belong to the Volcano Observatory of Southern Andes (OVDAS). Preliminary results show a correlation between seismicity and surface manifestation of fluid circulation. Seismicity has a heterogeneous distribution: most of the earthquake are concentrated is the master NS-striking fault with fluid circulation manifestations; however along the segments without surface manifestation of fluids do not have seismicity. These results suggest that fluid circulation mostly occur in areas with high seismicity, and thus, the increment in fluid pressure enhances

Flight elements: Fault detection and fault management

NASA Technical Reports Server (NTRS)

Lum, H.; Patterson-Hine, A.; Edge, J. T.; Lawler, D.

1990-01-01

Fault management for an intelligent computational system must be developed using a top down integrated engineering approach. An approach proposed includes integrating the overall environment involving sensors and their associated data; design knowledge capture; operations; fault detection, identification, and reconfiguration; testability; causal models including digraph matrix analysis; and overall performance impacts on the hardware and software architecture. Implementation of the concept to achieve a real time intelligent fault detection and management system will be accomplished via the implementation of several objectives, which are: Development of fault tolerant/FDIR requirement and specification from a systems level which will carry through from conceptual design through implementation and mission operations; Implementation of monitoring, diagnosis, and reconfiguration at all system levels providing fault isolation and system integration; Optimize system operations to manage degraded system performance through system integration; and Lower development and operations costs through the implementation of an intelligent real time fault detection and fault management system and an information management system.

Warming alters community size structure and ecosystem functioning

PubMed Central

Dossena, Matteo; Yvon-Durocher, Gabriel; Grey, Jonathan; Montoya, José M.; Perkins, Daniel M.; Trimmer, Mark; Woodward, Guy

2012-01-01

Global warming can affect all levels of biological complexity, though we currently understand least about its potential impact on communities and ecosystems. At the ecosystem level, warming has the capacity to alter the structure of communities and the rates of key ecosystem processes they mediate. Here we assessed the effects of a 4°C rise in temperature on the size structure and taxonomic composition of benthic communities in aquatic mesocosms, and the rates of detrital decomposition they mediated. Warming had no effect on biodiversity, but altered community size structure in two ways. In spring, warmer systems exhibited steeper size spectra driven by declines in total community biomass and the proportion of large organisms. By contrast, in autumn, warmer systems had shallower size spectra driven by elevated total community biomass and a greater proportion of large organisms. Community-level shifts were mirrored by changes in decomposition rates. Temperature-corrected microbial and macrofaunal decomposition rates reflected the shifts in community structure and were strongly correlated with biomass across mesocosms. Our study demonstrates that the 4°C rise in temperature expected by the end of the century has the potential to alter the structure and functioning of aquatic ecosystems profoundly, as well as the intimate linkages between these levels of ecological organization. PMID:22496185

Are Stronger North-Atlantic Southwesterlies the Forcing to the Late-Winter Warming in Europe?

NASA Technical Reports Server (NTRS)

Otterman, J.; Atlas, Robert; Chou, S.-H.; Jusem, J. C.; Pielke, R. A., Sr.; Chase, T. N.; Rogers, J.; Russell, G. L.; Schubert, S. D.; Sud, Y. C.

2001-01-01

We examine a possible mechanism leading to late-winter warming and thus to an early spring in Europe. From the NCEP Reanalysis, we extract for the years 1948-1999 ocean-surface winds over the eastern North Atlantic, and air temperatures at the surface, T(sub s), and at the 500 mb level, T(sub 500), in late-winter and spring. T(sub s) is extracted at six European locations, all at 50.5 N, ranging in longitude from 1.9 E (northeastern France) to 26.2 E (Ukraine). To quantify the advection of maritime air into Europe, we evaluate for 3-pentad groups the Index I(sub na) of the southwesterlies at 45 N; 20 W: I(sub na) is the average wind speed at this point if the direction is from the quadrant 180-270 deg (when the direction is different, the contribution counts as zero). In late winter correlations C(sub it) between the Index I(sub na) and the temperature T(sub s) are substantial, up to the 0.6 level, in western Europe (but weaker correlations for Poland and Ukraine). C(sub it) drops sharply by mid-March, taking occasionally negative values subsequently. This drop in C(sub it) indicates that maritime air advection is no longer associated closely with the surface-air warming, the role of immolation becomes important, and thus the drop in C(sub it) marks the arrival of spring. Correlations C(sub i delta) between I(sub na) and our lapse-rate parameter delta, the difference between T(sub s) and T(sub 500), indicate that the flow of warm maritime-air from the North Atlantic into this 'corridor' at 50.5 N is predominantly at low tropospheric level. By computing the best linear fit to I(sub na) and T(sub s), the trends for the period 1948-1999 are evaluated. The trends are appreciable in the second half of February and the first half of March. Our 3-pentad analysis points to the interval from mid-February to mid-March as the end-of-winter period in which the southwesterlies over the eastern North Atlantic become stronger and the surface-air temperatures in Europe rise

Northern Galápagos Corals Reveal Twentieth Century Warming in the Eastern Tropical Pacific

NASA Astrophysics Data System (ADS)

Jimenez, Gloria; Cole, Julia E.; Thompson, Diane M.; Tudhope, Alexander W.

2018-02-01

Models and observations disagree regarding sea surface temperature (SST) trends in the eastern tropical Pacific. We present a new Sr/Ca-SST record that spans 1940-2010 from two Wolf Island corals (northern Galápagos). Trend analysis of the Wolf record shows significant warming on multiple timescales, which is also present in several other records and gridded instrumental products. Together, these data sets suggest that most of the eastern tropical Pacific has warmed over the twentieth century. In contrast, recent decades have been characterized by warming during boreal spring and summer (especially north of the equator), and subtropical cooling during boreal fall and winter (especially south of the equator). These SST trends are consistent with the effects of radiative forcing, mitigated by cooling due to wind forcing during boreal winter, as well as intensified upwelling and a strengthened Equatorial Undercurrent.

The Tropical Western Hemisphere Warm Pool

NASA Astrophysics Data System (ADS)

Wang, Chunzai; Enfield, David B.

The Western Hemisphere warm pool (WHWP) of water warmer than 28.5°C extends from the eastern North Pacific to the Gulf of Mexico and the Caribbean, and at its peak, overlaps with the tropical North Atlantic. It has a large seasonal cycle and its interannual fluctuations of area and intensity are significant. Surface heat fluxes warm the WHWP through the boreal spring to an annual maximum of SST and areal extent in the late summer/early fall, associated with eastern North Pacific and Atlantic hurricane activities and rainfall from northern South America to the southern tier of the United States. SST and area anomalies occur at high temperatures where small changes can have a large impact on tropical convection. Observations suggest that a positive ocean-atmosphere feedback operating through longwave radiation and associated cloudiness is responsible for the WHWP SST anomalies. Associated with an increase in SST anomalies is a decrease in atmospheric sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less longwave radiation loss from the surface, which then reinforces SST anomalies.

Fault-related clay authigenesis along the Moab Fault: Implications for calculations of fault rock composition and mechanical and hydrologic fault zone properties

USGS Publications Warehouse

Solum, J.G.; Davatzes, N.C.; Lockner, D.A.

2010-01-01

The presence of clays in fault rocks influences both the mechanical and hydrologic properties of clay-bearing faults, and therefore it is critical to understand the origin of clays in fault rocks and their distributions is of great importance for defining fundamental properties of faults in the shallow crust. Field mapping shows that layers of clay gouge and shale smear are common along the Moab Fault, from exposures with throws ranging from 10 to ???1000 m. Elemental analyses of four locations along the Moab Fault show that fault rocks are enriched in clays at R191 and Bartlett Wash, but that this clay enrichment occurred at different times and was associated with different fluids. Fault rocks at Corral and Courthouse Canyons show little difference in elemental composition from adjacent protolith, suggesting that formation of fault rocks at those locations is governed by mechanical processes. Friction tests show that these authigenic clays result in fault zone weakening, and potentially influence the style of failure along the fault (seismogenic vs. aseismic) and potentially influence the amount of fluid loss associated with coseismic dilation. Scanning electron microscopy shows that authigenesis promotes that continuity of slip surfaces, thereby enhancing seal capacity. The occurrence of the authigenesis, and its influence on the sealing properties of faults, highlights the importance of determining the processes that control this phenomenon. ?? 2010 Elsevier Ltd.

Earthquake swarms and local crustal spreading along major strike-slip faults in California

USGS Publications Warehouse

Weaver, C.S.; Hill, D.P.

1978-01-01

Earthquake swarms in California are often localized to areas within dextral offsets in the linear trend in active fault strands, suggesting a relation between earthquake swarms and local crustal spreading. Local crustal spereading is required by the geometry of dextral offsets when, as in the San Andreas system, faults have dominantly strike-slip motion with right-lateral displacement. Three clear examples of this relation occur in the Imperial Valley, Coso Hot Springs, and the Danville region, all in California. The first two of these areas are known for their Holocene volcanism and geothermal potential, which is consistent with crustal spreading and magmatic intrusion. The third example, however, shows no evidence for volcanism or geothermal activity at the surface. ?? 1978 Birkha??user Verlag.

Anthropogenic Warming Impacts on Today's Sierra Nevada Snowpack and Flood Severity

NASA Astrophysics Data System (ADS)

Huang, X.; Hall, A. D.; Berg, N.

2017-12-01

Focusing on this recent extreme wet year over California, this study investigates the warming impacts on the snowpack and the flood severity over the Sierra Nevada (SN), where the majority of the precipitation occurs during the winter season and early spring. One of our goals is to quantify anthropogenic warming impacts on the snow water equivalent (SWE) including recent historical warming and prescribed future projected warming scenarios; This work also explores to what extent flooding risk has increased under those warming cases. With a good representation of the historical precipitation and snowpack over the Sierra Nevada from the historical reference run at 9km (using WRF), the results from the offline Noah-MP simulations with perturbed near-surface temperatures reveal magnificent impacts of warming to the loss of the average snowpack. The reduction of the SWE under warming mainly results from the decreased rain-to-snow conversion with a weaker effect from increased snowmelt. Compared to the natural case, the past industrial warming decreased the maximum SWE by about one-fifth averaged over the study area. Future continuing warming can result in around one-third reduction of current maximum SWE under RCP4.5 emissions scenario, and the loss can reach to two-thirds under RCP8.5 as a "business-as-usual" condition. The impact of past warming is particularly outstanding over the North SN region where precipitation dominates and over the middle elevation regions where the snow mainly distributes. In the future, the warming impact on SWE progresses to higher regions, and so to the south and east. Under the business-as-usual scenario, the projected mid-elevation snowpack almost disappears by April 1st with even high-elevation snow reduced by about half. Along with the loss of the snowpack, as the temperature warms, floods can also intensify with increased early season runoff especially under heavy-rainy days caused by the weakened rain-to-snow processes and

Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices

NASA Astrophysics Data System (ADS)

Funk, C.; Hoell, A.; Shukla, S.; Bladé, I.; Liebmann, B.; Roberts, J. B.; Robertson, F. R.; Husak, G.

2014-03-01

In southern Ethiopia, Eastern Kenya, and southern Somalia, poor boreal spring rains in 1999, 2000, 2004, 2007, 2008, 2009, and 2011 contributed to severe food insecurity and high levels of malnutrition. Predicting rainfall deficits in this region on seasonal and decadal time frames can help decision makers implement disaster risk reduction measures while guiding climate-smart adaptation and agricultural development. Building on recent research that links more frequent droughts in that region to a stronger Walker Circulation, warming in the Indo-Pacific warm pool, and an increased western Pacific sea surface temperature (SST) gradient, we show that the two dominant modes of East African boreal spring rainfall variability are tied, respectively, to western-central Pacific and central Indian Ocean SST. Variations in these rainfall modes can be predicted using two previously defined SST indices - the West Pacific Gradient (WPG) and Central Indian Ocean index (CIO), with the WPG and CIO being used, respectively, to predict the first and second rainfall modes. These simple indices can be used in concert with more sophisticated coupled modeling systems and land surface data assimilations to help inform early warning and guide climate outlooks.

Shallow Seismic Reflection Study of Recently Active Fault Scarps, Mina Deflection, Western Nevada

NASA Astrophysics Data System (ADS)

Black, R. A.; Christie, M.; Tsoflias, G. P.; Stockli, D. F.

2006-12-01

During the spring and summer of 2006 University of Kansas geophysics students and faculty acquired shallow, high resolution seismic reflection data over actively deforming alluvial fans developing across the Emmigrant Peak (in Fish Lake Valley) and Queen Valley Faults in western Nevada. These normal faults represent a portion of the transition from the right-lateral deformation associated with the Walker Lane/Eastern California Shear Zone to the normal and left-lateral faulting of the Mina Deflection. Data were gathered over areas of recent high resolution geological mapping and limited trenching by KU students. An extensive GPR data grid was also acquired. The GPR results are reported in Christie, et al., 2006. The seismic data gathered in the spring included both walkaway tests and a short CMP test line. These data indicated that a very near-surface P-wave to S-wave conversion was taking place and that very high quality S-wave reflections were probably dominating shot records to over one second in time. CMP lines acquired during the summer utilized a 144 channel networked Geode system, single 28 hz geophones, and a 30.06 downhole rifle source. Receiver spacing was 0.5 m, source spacing 1.0m and CMP bin spacings were 0.25m for all lines. Surveying was performed using an RTK system which was also used to develop a concurrent high resolution DEM. A dip line of over 400m and a strike line over 100m in length were shot across the active fan scarp in Fish Lake Valley. Data processing is still underway. However, preliminary interpretation of common-offset gathers and brute stacks indicates very complex faulting and detailed stratigraphic information to depths of over 125m. Depth of information was actually limited by the 1024ms recording time. Several west-dipping normal faults downstep towards the basin. East-dipping antithetic normal faulting is extensive. Several distinctive stratigraphic packages are bound by the faults and apparent unconformitites. A CMP dip line

Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

NASA Astrophysics Data System (ADS)

Chavagnac, Valérie; Ceuleneer, Georges; Monnin, Christophe; Lansac, Benjamin; Hoareau, Guilhem; Boulart, Cédric

2013-07-01

We report on the mineralogical assemblages found in the hyperalkaline springs hosted on Liguria and Oman ophiolites based on exhaustive X-ray diffraction and scanning electron microprobe analyses. In Liguria, hyperalkaline springs produce a thin brownish calcite precipitate that covers the bedrock due to the concomitant atmospheric CO2 uptake and neutralization of the hyperalkaline waters. No brucite and portlandite minerals are observed. The discharge of alkaline waters in Oman ophiolite forms white-orange precipitates. Calcium carbonate minerals (calcite and/or aragonite) are the most abundant and ubiquitous precipitates and are produced by the same mechanism as in Liguria. This process is observed as a thin surface crust made of rhombohedral calcite. Morphological features of aragonite vary from needle-, bouquet-, dumbbell-, spheroidal-like habitus according to the origin of carbon, temperature, and ionic composition of the hyperalkaline springs, and the biochemical and organic compounds. Brucite is observed both at hyperalkaline springs located at the thrust plane and at the paleo-Moho. The varying mixing proportions between the surface runoff waters and the hyperalkaline ones control brucite precipitation. The layered double hydroxide minerals occur solely in the vicinity of hyperalkaline springs emerging within the bedded gabbros. Finally, the dominant mineralogical associations we found in Oman (Ca-bearing carbonates and brucite) in a serpentinizing environment driven by the meteoric waters are surprisingly the same as those observed at the Lost City hydrothermal site in a totally marine environment.

Vegetation masking effect on future warming and snow albedo feedback in a boreal forest region of northern Eurasia according to MIROC-ESM

NASA Astrophysics Data System (ADS)

Abe, Manabu; Takata, Kumiko; Kawamiya, Michio; Watanabe, Shingo

2017-09-01

The Earth system model, Model for Interdisciplinary Research on Climate-Earth system model (MIROC-ESM), in which the leaf area index (LAI) is calculated interactively with an ecological land model, simulated future changes in the snow water equivalent under the scenario of global warming. Using MIROC-ESM, the effects of the snow albedo feedback (SAF) in a boreal forest region of northern Eurasia were examined under the possible climate future scenario RCP8.5. The simulated surface air temperature (SAT) in spring greatly increases across Siberia and the boreal forest region, whereas the snow cover decreases remarkably only in western Eurasia. The large increase in SAT across Siberia is attributed to strong SAF, which is caused by both the reduced snow-covered fraction and the reduced surface albedo of the snow-covered portion due to the vegetation masking effect in those grid cells. A comparison of the future changes with and without interactive LAI changes shows that in Siberia, the vegetation masking effect increases the spring SAF by about two or three times and enhances the spring warming by approximately 1.5 times. This implies that increases in vegetation biomass in the future are a potential contributing factor to warming trends and that further research on the vegetation masking effect is needed for reliable future projection.

Impact of the Spring SST Gradient between the Tropical Indian Ocean and Western Pacific on Landfalling Tropical Cyclone Frequency in China

NASA Astrophysics Data System (ADS)

Wang, Lei; Chen, Guanghua

2018-06-01

The present study identifies a significant influence of the sea surface temperature gradient (SSTG) between the tropical Indian Ocean (TIO; 15°S-15°N, 40°-90°E) and the western Pacific warm pool (WWP; 0°-15°N, 125°-155°E) in boreal spring on tropical cyclone (TC) landfall frequency in mainland China in boreal summer. During the period 1979-2015, a positive spring SSTG induces a zonal inter-basin circulation anomaly with lower-level convergence, mid-tropospheric ascendance and upper-level divergence over the west-central TIO, and the opposite situation over the WWP, which produces lower-level anomalous easterlies and upper-level anomalous westerlies between the TIO and WWP. This zonal circulation anomaly further warms the west-central TIO by driving warm water westward and cools the WWP by inducing local upwelling, which facilitates the persistence of the anomaly until the summer. Consequently, lower-level negative vorticity, strong vertical wind shear and lower-level anticyclonic anomalies prevail over most of the western North Pacific (WNP), which decreases the TC genesis frequency. Meanwhile, there is an anomalous mid-tropospheric anticyclone over the main WNP TC genesis region, meaning a westerly anomaly dominates over coastal regions of mainland China, which is unfavorable for steering TCs to make landfall in mainland China during summer. This implies that the spring SSTG may act as a potential indicator for TC landfall frequency in mainland China.

The Confederated Tribes of the Warm Springs Indian Reservation of Oregon John Day Basin Office : Watershed Restoration Projects : Annual Report, 2000.

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

Confederated Tribes of the Warm Springs Reservation of Oregon. John Day Basin Office.

2001-03-01

The John Day is the second longest free-flowing river in the contiguous United States and the longest containing entirely unsupplemented runs of anadromous fish. Located in eastern Oregon, the basin drains over 8,000 square miles--Oregon's third largest drainage basin--and incorporates portions of eleven counties. Originating in the Strawberry Mountains near Prairie City, the John Day River flows 284 miles in a northwesterly direction, entering the Columbia River approximately four miles upstream of the John Day dam. With wild runs of spring Chinook salmon and summer steelhead, red band, westslope cutthroat, and redband trout, the John Day system is truly amore » basin with national significance. Most all of the entire John Day basin was ceded to the Federal government in 1855 by the Confederated Tribes of the Warm Springs Reservation of Oregon (Tribes). In 1997, the Tribes established an office in the Basin to coordinate restoration projects, monitoring, planning and other watershed activities on private and public lands. Using funding from the Bonneville Power Administration, Bureau of Reclamation, and others, the John Day Basin Office (JDBO) subcontracts the majority of its construction implementation activities with the Grant Soil and Water Conservation District (GSWCD), also located in the town of John Day. The GSWCD completes the landowner contact, preliminary planning, engineering design, permitting, construction contracting, and construction implementation phases of most projects. The JDBO completes the planning, grant solicitation/review, environmental compliance, administrative contracting, monitoring, and reporting portion of the program. Most phases of project planning, implementation, and monitoring are coordinated with the private landowners and basin agencies, such as the Oregon Department of Fish and Wildlife and Oregon Water Resources Department. In 2000, the JDBO and GSWCD proposed continuation of a successful partnership between the two

The Confederated Tribes of the Warm Springs Indian Reservation of Oregon John Day Basin Office : Watershed Restoration Projects : Annual Report, 2001.

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

Confederated Tribes of the Warm Springs Reservation of Oregon. John Day Basin Office.

The John Day River is the nation's second longest free-flowing river in the contiguous United States, which is entirely unsupplemented for it's runs of anadromous fish. Located in eastern Oregon, the John Day Basin drains over 8,000 square miles, is Oregon's fourth largest drainage basin, and the basin incorporates portions of eleven counties. Originating in the Strawberry Mountains near Prairie City, the mainstem John Day River flows 284 miles in a northwesterly direction entering the Columbia River approximately four miles upstream of the John Day dam. With wild runs of spring Chinook salmon, summer steelhead, westslope cutthroat, and redband andmore » bull trout, the John Day system is truly a basin with national significance. The Majority of the John Day Basin was ceded to the Federal government in 1855 by the Confederated Tribes of the Warm Springs Reservation of Oregon (Tribes). In 1997, the Tribes established an office in John Day to coordinate basin restoration projects, monitoring, planning, and other watershed restoration activities on private and public lands. Once established, the John Day Basin Office (JDBO) formed a partnership with the Grant Soil and Water Conservation District (GSWCD), also located in John Day, who subcontracts the majority of the construction implementation activities for these restoration projects from the JDBO. The GSWCD completes the landowner contact, preliminary planning, engineering design, permitting, construction contracting, and construction implementation phases of most projects. The JDBO completes the planning, grant solicitation/defense, environmental compliance, administrative contracting, monitoring, and reporting portion of the program. Most phases of project planning, implementation, and monitoring are coordinated with the private landowners and basin agencies, such as the Oregon Department of Fish and Wildlife and Oregon Water Resources Department. In 2001, the JDBO and GSWCD continued their successful

Walthère Victor Spring - A Forerunner in the Study of the Greenhouse Effect

NASA Astrophysics Data System (ADS)

Demarée, Gaston R.; Verheyden, Rosiane

2016-01-01

In 1886, an article by Walthère Spring and Léon Roland, two scientists from the University of Liège, dealing with the carbon dioxide content in the atmosphere in Liège appeared in the "Mẻmoires" of the Royal Academy of Belgium. In order to explain the difference between temperatures in the city of Liège and those observed in that city's environs, the authors invoked the high level of atmospheric CO2. Although the climatological argument was rather weak and the article concerned only a local impact, it is obvious that Spring can be viewed as a precursor of Svante Arrhenius who foresaw global warming in 1895-1896.

Paleohydrologic record of spring deposits in and around Pleistocene pluvial Lake Tecopa, southeastern California

USGS Publications Warehouse

Nelson, Stephen T.; Karlsson, Haraldur R.; Paces, James B.; Tingey, David G.; Ward, Stephen; Peters, Mark T.

2001-01-01

Tufa (spring) deposits in the Tecopa basin, California, reflect the response of arid groundwater regimes to wet climate episodes. Two types of tufa are represented, informally defined as (1) an easily disaggregated, fine-grained mixture of calcite and quartz (friable tufa) in the southwest Tecopa Valley, and (2) hard, vuggy micrite, laminated carbonate, and carbonate-cemented sands and gravels (indurated tufa) along the eastern margin of Lake Tecopa. High δ18OVSMOW (Vienna standard mean ocean water) water values, field relations, and the texture of friable tufa suggest rapid nucleation of calcite as subaqueous, fault- controlled groundwater discharge mixed with high-pH, hypersaline lake water. Variations between δ18OVSMOW and δ13CPDB (Peedee belemnite) values relative to other closed basin lakes such as the Great Salt Lake and Lake Lahontan suggest similarities in climatic and hydrologic settings. Indurated tufa, also fault controlled, formed mounds and associated feeder systems as well as stratabound carbonate-cemented ledges. Both deposits represent discharge of deeply circulated, high total dissolved solids, and high pCO2 regional groundwater with kinetic enrichments of as much as several per mil for δ18OVSMOW values. Field relations show that indurated tufa represents episodic discharge, and U-series ages imply that discharge was correlated with cold, wet climate episodes. In response to both the breaching of the Tecopa basin and a modern arid climate, most discharge has changed from fault-controlled locations near basin margins to topographic lows of the Amargosa River drainage at elevations 30–130 m lower. Because of episodic climate change, spring flows may have relocated from basin margin to basin center multiple times.

Impacts of climate change on spring flower tourism in Beijing, China

NASA Astrophysics Data System (ADS)

Wang, Huanjiong

2016-04-01

midpoint of frequency distribution curve) kept stable. The best date of spring flower tourism was significantly correlated with spring temperature (R=-0.66, P<0.01), with an increase in spring temperature of 1 °C causing the best date earlier by 4.0 days. In the context of future global warming, it is crucial to enhance the ability to predict flowering time, so as to provide reference for tourism administrators and the tourists to make better tourism arrangements.

Role of 20th tropical precipitation on ENSO amplitude changes due to greenhouse warming in CMIP5

NASA Astrophysics Data System (ADS)

Ham, Yoo-Geun; Kug, Jong-Seong

2016-04-01

This study examines the relationship between the intermodel diversities of the present-climate climatology and those of ENSO amplitude change under global warming in the Coupled Model Intercomparison Project phase 5 (CMIP5) models. The models with increased ENSO amplitude under greenhouse warming (i.e., 'ENSO-amplified models') tend to simulate a 20th century stronger climatological ITCZ and SPCZ over the central-eastern Pacific that are located further away from the equator during boreal spring. Moisture budget analysis indicates that those climatological differences lead to stronger positive climatological precipitation change over the off-equatorial central-eastern Pacific under greenhouse warming. The stronger positive climatological precipitation change enhances the air-sea coupling strength over the central-eastern Pacific, which leads to increase the ENSO amplitude.

New Airborne LiDAR Survey of the Hayward Fault, Northern California

NASA Astrophysics Data System (ADS)

Brocher, T. M.; Prentice, C. S.; Phillips, D. A.; Bevis, M.; Shrestha, R. L.

2007-12-01

We present a digital elevation model (DEM) constructed from newly acquired high-resolution LIght Detection and Ranging (LIDAR) data along the Hayward Fault in Northern California. The data were acquired by the National Center for Airborne Laser Mapping (NCALM) in the spring of 2007 in conjunction with a larger regional airborne LIDAR survey of the major crustal faults in northern California coordinated by UNAVCO and funded by the National Science Foundation as part of GeoEarthScope. A consortium composed of the U. S. Geological Survey, Pacific Gas & Electric Company, the San Francisco Public Utilities Commission, and the City of Berkeley separately funded the LIDAR acquisition along the Hayward Fault. Airborne LIDAR data were collected within a 106-km long by 1-km wide swath encompassing the Hayward Fault that extended from San Pablo Bay on the north to the southern end of its restraining stepover with the Calaveras Fault on the south. The Hayward Fault is among the most urbanized faults in the nation. With its most recent major rupture in 1868, it is well within the time window for its next large earthquake, making it an excellent candidate for a "before the earthquake" DEM image. After the next large Hayward Fault event, this DEM can be compared to a post-earthquake LIDAR DEM to provide a means for a detailed analysis of fault slip. In order to minimize location errors, temporary GPS ground control stations were deployed by Ohio State University, UNAVCO, and student volunteers from local universities to augment the available continuous GPS arrays operated in the study area by the Bay Area Regional Deformation (BARD) Network and the Plate Boundary Observatory (PBO). The vegetation cover varies along the fault zone: most of the vegetation is non-native species. Photographs from the 1860s show very little tall vegetation along the fault zone. A number of interesting geomorphic features are associated with the Hayward Fault, even in urbanized areas. Sag ponds and

Fluid-rock interaction recorded in fault rocks of the Nobeoka Thrust, fossilized megasplay fault in an ancient accretionary complex

NASA Astrophysics Data System (ADS)

Hasegawa, R.; Yamaguchi, A.; Fukuchi, R.; Kitamura, Y.; Kimura, G.; Hamada, Y.; Ashi, J.; Ishikawa, T.

2017-12-01

The relationship between faulting and fluid behavior has been in debate. In this study, we clarify the fluid-rock interaction in the Nobeoka Thrust by major/trace element composition analysis using the boring core of the Nobeoka Thrust, an exhumed analogue of an ancient megasplay fault in Shimanto accretionary complex, southwest Japan. The hanging wall and the footwall of the Nobeoka Thrust show difference in lithology and metamorphic grade, and their maximum burial temperature is estimated from vitrinite reflectance analysis to be 320 330°C and 250 270°C, respectively (Kondo et al., 2005). The fault zone was formed in a fluid-rich condition, as evidenced by warm fluid migration suggested by fluid inclusion analysis (Kondo et al., 2005), implosion brecciation accompanied by carbonate precipitation followed by formation of pseudotachylyte (Okamoto et al., 2006), ankerite veins coseismically formed under reducing conditions (Yamaguchi et al., 2011), and quartz veins recording stress rotation in seismic cycles (Otsubo et al., 2016). In this study, first we analyzed the major/trace element composition across the principal slip zone (PSZ) of the Nobeoka Thrust by using fragments of borehole cores penetrated through the Nobeoka Thrust. Many elements fluctuated just above the PSZ, whereas K increase and Na, Si decrease suggesting illitization of plagioclase, as well as positive anomalies in Li and Cs were found within the PSZ. For more detail understanding, we observed polished slabs and thin sections of the PSZ. Although grain size reduction of deformed clast and weak development of foliation were observed entirely in the PSZ by macroscopic observation, remarkable development of composite planar fabric nor evidence of friction melting were absent. In this presentation, we show the result of major/trace element composition corresponding to the internal structure of PSZ, and discuss fluid-rock interaction and its impact to megasplay fault activity in subduction zones.

Why the 2002 Denali fault rupture propagated onto the Totschunda fault: implications for fault branching and seismic hazards

USGS Publications Warehouse

Schwartz, David P.; Haeussler, Peter J.; Seitz, Gordon G.; Dawson, Timothy E.

2012-01-01

The propagation of the rupture of the Mw7.9 Denali fault earthquake from the central Denali fault onto the Totschunda fault has provided a basis for dynamic models of fault branching in which the angle of the regional or local prestress relative to the orientation of the main fault and branch plays a principal role in determining which fault branch is taken. GeoEarthScope LiDAR and paleoseismic data allow us to map the structure of the Denali-Totschunda fault intersection and evaluate controls of fault branching from a geological perspective. LiDAR data reveal the Denali-Totschunda fault intersection is structurally simple with the two faults directly connected. At the branch point, 227.2 km east of the 2002 epicenter, the 2002 rupture diverges southeast to become the Totschunda fault. We use paleoseismic data to propose that differences in the accumulated strain on each fault segment, which express differences in the elapsed time since the most recent event, was one important control of the branching direction. We suggest that data on event history, slip rate, paleo offsets, fault geometry and structure, and connectivity, especially on high slip rate-short recurrence interval faults, can be used to assess the likelihood of branching and its direction. Analysis of the Denali-Totschunda fault intersection has implications for evaluating the potential for a rupture to propagate across other types of fault intersections and for characterizing sources of future large earthquakes.

Interannual variations in spring phenology and their response to climate change across the Tibetan Plateau from 1982 to 2013.

PubMed

Liu, Lingling; Zhang, Xiaoyang; Donnelly, Alison; Liu, Xinjie

2016-10-01

Land surface phenology has been widely used to evaluate the effects of climate change on terrestrial ecosystems in recent decades. Climate warming on the Tibetan Plateau (1960-2010, 0.2 °C/decade) has been found to be greater than the global average (1951-2012, 0.12 °C/decade), which has had a significant impact on the timing of spring greenup. However, the magnitude and direction of change in spring phenology and its response to warming temperature and precipitation are currently under scientific debate. In an attempt to explore this issue further, we detected the onset of greenup based on the time series of daily two-band enhanced vegetation index (EVI2) from the advanced very high resolution radiometer (AVHRR) long-term data record (LTDR; 1982-1999) and Moderate Resolution Imaging Spectroradiometer (MODIS) Climate Modeling Grid (CMG; 2000-2013) using hybrid piecewise logistic models. Further, we examined the temporal trend in greenup onset in both individual pixels and ecoregions across the entire Tibetan Plateau over the following periods: 1982-1999, 2000-2013, and 1982-2013. The interannual variation in greenup onset was linked to the mean temperature and cumulative precipitation in the preceding month, and total precipitation during winter and spring, respectively. Finally, we investigated the relationship between interannual variation in greenup onset dates and temperature and precipitation from 1982 to 2013 at different elevational zones for different ecoregions. The results revealed no significant trend in the onset of greenup from 1982 to 2013 in more than 86 % of the Tibetan Plateau. For each study period, statistically significant earlier greenup trends were observed mainly in the eastern meadow regions while later greenup trends mainly occurred in the southwestern steppe and meadow regions both with areal coverage of less than 8 %. Although spring phenology was negatively correlated with spring temperature and precipitation in the majority of

Active Fault Topography and Fault Outcrops in the Central Part of the Nukumi fault, the 1891 Nobi Earthquake Fault System, Central Japan

NASA Astrophysics Data System (ADS)

Sasaki, T.; Ueta, K.; Inoue, D.; Aoyagi, Y.; Yanagida, M.; Ichikawa, K.; Goto, N.

2010-12-01

It is important to evaluate the magnitude of earthquake caused by multiple active faults, taking into account the simultaneous effects. The simultaneity of adjacent active faults are often decided on the basis of geometric distances except for known these paleoseismic records. We have been studied the step area between the Nukumi fault and the Neodani fault, which appeared as consecutive ruptures in the 1891 Nobi earthquake, since 2009. The purpose of this study is to establish innovation in valuation technique of the simultaneity of adjacent active faults in addition to the paleoseismic record and the geometric distance. Geomorphological, geological and reconnaissance microearthquake surveys are concluded. The present work is intended to clarify the distribution of tectonic geomorphology along the Nukumi fault and the Neodani fault by high-resolution interpretations of airborne LiDAR DEM and aerial photograph, and the field survey of outcrops and location survey. The study area of this work is the southeastern Nukumi fault and the northwestern Neodani fault. We interpret DEM using shaded relief map and stereoscopic bird's-eye view made from 2m mesh DEM data which is obtained by airborne laser scanner of Kokusai Kogyo Co., Ltd. Aerial photographic survey is for confirmation of DEM interpretation using 1/16,000 scale photo. As a result of topographic survey, we found consecutive tectonic topography which is left lateral displacement of ridge and valley lines and reverse scarplets along the Nukumi fault and the Neodani fault . From Ogotani 2km southeastern of Nukumi pass which is located at the southeastern end of surface rupture along the Nukumi fault by previous study to Neooppa 9km southeastern of Nukumi pass, we can interpret left lateral topographies and small uphill-facing fault scarps on the terrace surface by detail DEM investigation. These topographies are unrecognized by aerial photographic survey because of heavy vegetation. We have found several new

Insights into contaminant transport from unconventional oil and gas developments from analog system analysis of methane-bearing thermal springs in the northern Canadian Rocky Mountains

NASA Astrophysics Data System (ADS)

Ferguson, Grant; Grasby, Stephen E.

2018-03-01

Natural gas is currently being produced from shales of the Montney and Liard basins in western Canada. Production requires hydraulic fracturing due to the low permeability of the shales in the basins. Stratigraphically equivalent shales are present in the northern Canadian Rocky Mountains. Thermal springs with notable hydrocarbon concentrations occur where large-scale faults intersect the same shale units that are the focus of gas development, indicating that under certain circumstances, connection of deep fractured shales to the land surface is possible. To constrain these conditions, simulations were conducted for the spring with the highest hydrocarbon flux (Toad River Spring), results of which indicate that in order to supply sufficient water to a fault to support measurable advection, the effective permeability of the shales in these structurally deformed areas must be one to four orders of magnitude higher than in areas of active gas production to the east. The spatial scale of enhanced permeability is much greater than that which is achieved by hydraulic fracturing and the mechanism of maintaining high pressures at depth is more persistent in time. Examination of groundwater velocities suggests that upward migration of solutes from hydraulic fracturing may take decades to centuries. Results also indicate that any temperature anomaly will be associated with transport along a fault at such velocities. No such temperature anomaly has been documented in regions with unconventional oil and gas development to date. Such an anomaly would be diagnostic of a deep solute source.

Predeployment validation of fault-tolerant systems through software-implemented fault insertion

NASA Technical Reports Server (NTRS)

Czeck, Edward W.; Siewiorek, Daniel P.; Segall, Zary Z.

1989-01-01

Fault injection-based automated testing (FIAT) environment, which can be used to experimentally characterize and evaluate distributed realtime systems under fault-free and faulted conditions is described. A survey is presented of validation methodologies. The need for fault insertion based on validation methodologies is demonstrated. The origins and models of faults, and motivation for the FIAT concept are reviewed. FIAT employs a validation methodology which builds confidence in the system through first providing a baseline of fault-free performance data and then characterizing the behavior of the system with faults present. Fault insertion is accomplished through software and allows faults or the manifestation of faults to be inserted by either seeding faults into memory or triggering error detection mechanisms. FIAT is capable of emulating a variety of fault-tolerant strategies and architectures, can monitor system activity, and can automatically orchestrate experiments involving insertion of faults. There is a common system interface which allows ease of use to decrease experiment development and run time. Fault models chosen for experiments on FIAT have generated system responses which parallel those observed in real systems under faulty conditions. These capabilities are shown by two example experiments each using a different fault-tolerance strategy.

Abrupt physical and chemical changes during 1992-1999, Anderson Springs, SE Geyser Geothermal Field, California

USGS Publications Warehouse

Janik, Cathy J.; Goff, Fraser; Walter, Stephen R.; Sorey, Michael L.; Counce, Dale; Colvard, Elizabeth M.

2000-01-01

The Anderson Springs area is located about 90 miles (145 kilometers) north of San Francisco, California, in the southwestern part of Lake County. The area was first developed in the late 1800s as a health resort, which was active until the 1930s. Patrons drank a variety of cool to hot mineral waters from improved springs, swam in various baths and pools, and hiked in the rugged hills flanking Anderson Creek and its tributaries. In the bluffs to the south of the resort were four small mercury mines of the eastern Mayacmas quicksilver district. About 1,260 flasks of mercury were produced from these mines between 1909 and 1943. By the early 1970s, the higher ridges south and west of Anderson Springs became part of the southeast sector of the greater Geysers geothermal field. Today, several electric power plants are built on these ridges, producing energy from a vapor-dominated 240 °C reservoir. Only the main hot spring at Anderson Springs has maintained a recognizable identity since the 1930s. The hot spring is actually a cluster of seeps and springs that issue from a small fault in a ravine southwest of Anderson Creek. Published and unpublished records show that the maximum temperature (Tm) of this cluster fell gradually from 63°C in 1889 to 48°C in 1992. However, Tm of the cluster climbed to 77°C in 1995 and neared boiling (98°C) in 1998. A new cluster of boiling vents and small fumaroles (Tm = 99.3°C) formed in 1998 about 30 m north of the old spring cluster. Several evergreen trees on steep slopes immediately above these vents apparently were killed by the new activity. Thermal waters at Anderson Hot Springs are mostly composed of near-surface ground waters with some added gases and condensed steam from The Geysers geothermal system. Compared to gas samples from Southeast Geysers wells, the hot spring gases are higher in CO2 and lower in H2S and NH3. As the springs increased in temperature, however, the gas composition became more like the mean composition

Preliminary Pseudo 3-D Imagery of the State Line Fault, Stewart Valley, Nevada Using Seismic Reflection Data

NASA Astrophysics Data System (ADS)

Saldaña, S. C.; Snelson, C. M.; Taylor, W. J.; Beachly, M.; Cox, C. M.; Davis, R.; Stropky, M.; Phillips, R.; Robins, C.; Cothrun, C.

2007-12-01

The Pahrump Fault system is located in the central Basin and Range region and consists of three main fault zones: the Nopah range front fault zone, the State Line fault zone and the Spring Mountains range fault zone. The State Line fault zone is made up north-west trending dextral strike-slip faults that run parallel to the Nevada- California border. Previous geologic and geophysical studies conducted in and around Stewart Valley, located ~90 km from Las Vegas, Nevada, have constrained the location of the State Line fault zone to within a few kilometers. The goals of this project were to use seismic methods to definitively locate the northwestern most trace of the State Line fault and produce pseudo 3-D seismic cross-sections that can then be used to characterize the subsurface geometry and determine the slip of the State Line fault. During July 2007, four seismic lines were acquired in Stewart Valley: two normal and two parallel to the mapped traces of the State Line fault. Presented here are preliminary results from the two seismic lines acquired normal to the fault. These lines were acquired utilizing a 144-channel geode system with each of the 4.5 Hz vertical geophones set out at 5 m intervals to produce a 595 m long profile to the north and a 715 m long profile to the south. The vibroseis was programmed to produce an 8 s linear sweep from 20-160 Hz. These data returned excellent signal to noise and reveal subsurface lithology that will subsequently be used to resolve the subsurface geometry of the State Line fault. This knowledge will then enhance our understanding of the evolution of the State Line fault. Knowing how the State Line fault has evolved gives insight into the stick-slip fault evolution for the region and may improve understanding of how stress has been partitioned from larger strike-slip systems such as the San Andreas fault.

Geothermal investigation of spring and well waters of the Los Alamos Region, New Mexico

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

Goff, F.E.; Sayer, S.

1980-04-01

The chemical and isotopic characters of 20 springs and wells in the Los Alamos area were investigated for indications of geothermal potential. These waters were compared with known hot and mineral springs from adjacent Valles Caldera and San Ysidro. All waters in the Los Alamos area are composed of meteoric water. Isotopic data show that the two primary aquifers beneath the Los Alamos region have different recharge areas. Relatively high concentrations of lithium, arsenic, chlorine, boron, and fluorine in some of the Los Alamos wells suggest these waters may contain a small fraction of thermal/mineral water of deep origin. Thermalmore » water probably rises up high-angle faults associated with a graben of the Rio Grande rift now buried by the Pajarito Plateau.« less

Linear magnetic spring and spring/motor combination

NASA Technical Reports Server (NTRS)

Patt, Paul J. (Inventor); Stolfi, Fred R. (Inventor)

1991-01-01

A magnetic spring, or a spring and motor combination, providing a linear spring force characteristic in each direction from a neutral position, in which the spring action may occur for any desired coordinate of a typical orthogonal coordinate system. A set of magnets are disposed, preferably symmetrically about a coordinate axis, poled orthogonally to the desired force direction. A second set of magnets, respectively poled opposite the first set, are arranged on the sprung article. The magnets of one of the sets are spaced a greater distance apart than those of the other, such that an end magnet from each set forms a pair having preferably planar faces parallel to the direction of spring force, the faces being offset so that in a neutral position the outer edge of the closer spaced magnet set is aligned with the inner edge of the greater spaced magnet set. For use as a motor, a coil can be arranged with conductors orthogonal to both the magnet pole directions and the direction of desired spring force, located across from the magnets of one set and fixed with respect to the magnets of the other set. In a cylindrical coordinate system having axial spring force, the magnets are radially poled and motor coils are concentric with the cylinder axis.

Unified law of evolution of experimental gouge-filled fault for fast and slow slip events at slider frictional experiments

NASA Astrophysics Data System (ADS)

Ostapchuk, Alexey; Saltykov, Nikolay

2017-04-01

Excessive tectonic stresses accumulated in the area of rock discontinuity are released while a process of slip along preexisting faults. Spectrum of slip modes includes not only creeps and regular earthquakes but also some transitional regimes - slow-slip events, low-frequency and very low-frequency earthquakes. However, there is still no agreement in Geophysics community if such fast and slow events have mutual nature [Peng, Gomberg, 2010] or they present different physical phenomena [Ide et al., 2007]. Models of nucleation and evolution of fault slip events could be evolved by laboratory experiments in which regularities of shear deformation of gouge-filled fault are investigated. In the course of the work we studied deformation regularities of experimental fault by slider frictional experiments for development of unified law of evolution of fault and revelation of its parameters responsible for deformation mode realization. The experiments were conducted as a classic slider-model experiment, in which block under normal and shear stresses moves along interface. The volume between two rough surfaces was filled by thin layer of granular matter. Shear force was applied by a spring which deformed with a constant rate. In such experiments elastic energy was accumulated in the spring, and regularities of its releases were determined by regularities of frictional behaviour of experimental fault. A full spectrum of slip modes was simulated in laboratory experiments. Slight change of gouge characteristics (granule shape, content of clay), viscosity of interstitial fluid and level of normal stress make it possible to obtained gradual transformation of the slip modes from steady sliding and slow slip to regular stick-slip, with various amplitude of 'coseismic' displacement. Using method of asymptotic analogies we have shown that different slip modes can be specified in term of single formalism and preparation of different slip modes have uniform evolution law. It is shown

Spring operated accelerator and constant force spring mechanism therefor

NASA Technical Reports Server (NTRS)

Shillinger, G. L., Jr. (Inventor)

1977-01-01

A spring assembly consisting of an elongate piece of flat spring material formed into a spiral configuration and a free running spool in circumscribing relation to which this spring is disposed was developed. The spring has a distal end that is externally accessible so that when the distal end is drawn along a path, the spring unwinds against a restoring force present in the portion of the spring that resides in a transition region between a relatively straight condition on the path and a fully wound condition on the spool. When the distal end is released, the distal end is accelerated toward the spool by the force existing at the transition region which force is proportional to the cross-sectional area of the spring.

Increase in fault ride through capability of direct drive permanent magnet based wind farm using VSC-HVDC

NASA Astrophysics Data System (ADS)

Maleki, Hesamaldin; Ramachandaramurthy, V. K.; Lak, Moein

2013-06-01

Burning of fossil fuels and green house gasses causes global warming. This has led to governments to explore the use of green energies instead of fossil fuels. The availability of wind has made wind technology a viable alternative for generating electrical power. Hence, many parts of the world, especially Europe are experiencing a growth in wind farms. However, by increasing the number of wind farms connected to the grid, power quality and voltage stability of grid becomes a matter of concern. In this paper, VSC-HVDC control strategy which enables the wind farm to ride-through faults and regulate voltage for fault types is proposed. The results show that the wind turbine output voltage fulfills the E.ON grid code requirements, when subjected to three phase to ground fault. Hence, continues operation of the wind farm is achieved.

Winter warming as an important co-driver for Betula nana growth in western Greenland during the past century

PubMed Central

Hollesen, Jørgen; Buchwal, Agata; Rachlewicz, Grzegorz; Hansen, Birger U; Hansen, Marc O; Stecher, Ole; Elberling, Bo

2015-01-01

Growing season conditions are widely recognized as the main driver for tundra shrub radial growth, but the effects of winter warming and snow remain an open question. Here, we present a more than 100 years long Betula nana ring-width chronology from Disko Island in western Greenland that demonstrates a highly significant and positive growth response to both summer and winter air temperatures during the past century. The importance of winter temperatures for Betula nana growth is especially pronounced during the periods from 1910–1930 to 1990–2011 that were dominated by significant winter warming. To explain the strong winter importance on growth, we assessed the importance of different environmental factors using site-specific measurements from 1991 to 2011 of soil temperatures, sea ice coverage, precipitation and snow depths. The results show a strong positive growth response to the amount of thawing and growing degree-days as well as to winter and spring soil temperatures. In addition to these direct effects, a strong negative growth response to sea ice extent was identified, indicating a possible link between local sea ice conditions, local climate variations and Betula nana growth rates. Data also reveal a clear shift within the last 20 years from a period with thick snow depths (1991–1996) and a positive effect on Betula nana radial growth, to a period (1997–2011) with generally very shallow snow depths and no significant growth response towards snow. During this period, winter and spring soil temperatures have increased significantly suggesting that the most recent increase in Betula nana radial growth is primarily triggered by warmer winter and spring air temperatures causing earlier snowmelt that allows the soils to drain and warm quicker. The presented results may help to explain the recently observed ‘greening of the Arctic’ which may further accelerate in future years due to both direct and indirect effects of winter warming. PMID:25788025

Hydrogeology of northern Sierra de Chiapas, Mexico: a conceptual model based on a geochemical characterization of sulfide-rich karst brackish springs

NASA Astrophysics Data System (ADS)

Rosales Lagarde, Laura; Boston, Penelope J.; Campbell, Andrew R.; Hose, Louise D.; Axen, Gary; Stafford, Kevin W.

2014-09-01

Conspicuous sulfide-rich karst springs flow from Cretaceous carbonates in northern Sierra de Chiapas, Mexico. This is a geologically complex, tropical karst area. The physical, geologic, hydrologic and chemical attributes of these springs were determined and integrated into a conceptual hydrogeologic model. A meteoric source and a recharge elevation below 1,500 m are estimated from the spring-water isotopic signature regardless of their chemical composition. Brackish spring water flows at a maximum depth of 2,000 m, as inferred from similar chemical attributes to the produced water from a nearby oil well. Oil reservoirs may be found at depths below 2,000 m. Three subsurface environments or aquifers are identified based on the B, Li+, K+ and SiO2 concentrations, spring water temperatures, and CO2 pressures. There is mixing between these aquifers. The aquifer designated Local is shallow and contains potable water vulnerable to pollution. The aquifer named Northern receives some brackish produced water. The composition of the Southern aquifer is influenced by halite dissolution enhanced at fault detachment surfaces. Epigenic speleogenesis is associated with the Local springs. In contrast, hypogenic speleogenesis is associated with the brackish sulfidic springs from the Northern and the Southern environments.

Three-dimensional geologic framework modeling of faulted hydrostratigraphic units within the Edwards Aquifer, Northern Bexar County, Texas

USGS Publications Warehouse

Pantea, Michael P.; Cole, James C.

2004-01-01

This report describes a digital, three-dimensional faulted hydrostratigraphic model constructed to represent the geologic framework of the Edwards aquifer system in the area of San Antonio, northern Bexar County, Texas. The model is based on mapped geologic relationships that reflect the complex structures of the Balcones fault zone, detailed lithologic descriptions and interpretations of about 40 principal wells (and qualified data from numerous other wells), and a conceptual model of the gross geometry of the Edwards Group units derived from prior interpretations of depositional environments and paleogeography. The digital model depicts the complicated intersections of numerous major and minor faults in the subsurface, as well as their individual and collective impacts on the continuity of the aquifer-forming units of the Edwards Group and the Georgetown Formation. The model allows for detailed examination of the extent of fault dislocation from place to place, and thus the extent to which the effective cross-sectional area of the aquifer is reduced by faulting. The model also depicts the internal hydrostratigraphic subdivisions of the Edwards aquifer, consisting of three major and eight subsidiary hydrogeologic units. This geologic framework model is useful for visualizing the geologic structures within the Balcones fault zone and the interactions of en-echelon fault strands and flexed connecting fault-relay ramps. The model also aids in visualizing the lateral connections between hydrostratigraphic units of relatively high and low permeability across the fault strands. Introduction The Edwards aquifer is the principal source of water for municipal, agricultural, industrial, and military uses by nearly 1.5 million inhabitants of the greater San Antonio, Texas, region (Hovorka and others, 1996; Sharp and Banner, 1997). Discharges from the Edwards aquifer also support local recreation and tourism industries at Barton, Comal, and San Marcos Springs located

Microbial community composition and endolith colonization at an Arctic thermal spring are driven by calcite precipitation

USGS Publications Warehouse

Starke, Verena; Kirshtein, Julie; Fogel, Marilyn L.; Steele, Andrew

2013-01-01

Environmental conditions shape community composition. Arctic thermal springs provide an opportunity to study how environmental gradients can impose strong selective pressures on microbial communities and provide a continuum of niche opportunities. We use microscopic and molecular methods to conduct a survey of microbial community composition at Troll Springs on Svalbard, Norway, in the high Arctic. Microorganisms there exist under a wide range of environmental conditions: in warm water as periphyton, in moist granular materials, and in cold, dry rock as endoliths. Troll Springs has two distinct ecosystems, aquatic and terrestrial, together in close proximity, with different underlying environmental factors shaping each microbial community. Periphyton are entrapped during precipitation of calcium carbonate from the spring's waters, providing microbial populations that serve as precursors for the development of endolithic communities. This process differs from most endolith colonization, in which the rock predates the communities that colonize it. Community composition is modulated as environmental conditions change within the springs. At Troll, the aquatic environments show a small number of dominant operational taxonomic units (OTUs) that are specific to each sample. The terrestrial environments show a more even distribution of OTUs common to multiple samples.

Responses of two understory herbs, Maianthemum canadense and Eurybia macrophylla, to experimental forest warming: early emergence is the key to enhanced reproductive output.

PubMed

Jacques, Marie-Hélène; Lapointe, Line; Rice, Karen; Montgomery, Rebecca A; Stefanski, Artur; Reich, Peter B

2015-10-01

Understory herbs might be the most sensitive plant form to global warming in deciduous forests, yet they have been little studied in the context of climate change. A field experiment set up in Minnesota, United States simulated global warming in a forest setting and provided the opportunity to study the responses of Maianthemum canadense and Eurybia macrophylla in their natural environment in interaction with other components of the ecosystem. Effects of +1.7° and +3.4°C treatments on growth, reproduction, phenology, and gas exchange were evaluated along with treatment effects on light, water, and nutrient availability, potential drivers of herb responses. Overall, growth and gas exchanges of these two species were modestly affected by warming. They emerged up to 16 (E. macrophylla) to 17 d (M. canadense) earlier in the heated plots than in control plots, supporting early-season carbon gain under high light conditions before canopy closure. This additional carbon gain in spring likely supported reproduction. Eurybia macrophylla only flowered in the heated plots, and both species had some aspect of reproduction that was highest in the +1.7°C treatment. The reduced reproductive effort in the +3.4°C plots was likely due to reduced soil water availability, counteracting positive effects of warming. Global warming might improve fitness of herbaceous species in deciduous forests, mainly by advancing their spring emergence. However, other impacts of global warming such as drier soils in the summer might partly reduce the carbon gain associated with early emergence. © 2015 Botanical Society of America.

Characterising the hydrothermal circulation patterns beneath thermal springs in the limestones of the Carboniferous Dublin Basin, Ireland: a geophysical and geochemical approach.

NASA Astrophysics Data System (ADS)

Blake, Sarah; Henry, Tiernan; Muller, Mark R.; Jones, Alan G.; Moore, John Paul; Murray, John; Campanyà, Joan; Vozár, Jan; Walsh, John; Rath, Volker

2016-04-01

A hydrogeological conceptual model of the sources, circulation pathways and temporal variations of two low-enthalpy thermal springs is derived from a multi-disciplinary approach. The springs are situated in the Carboniferous limestones of the Dublin Basin, in east-central Ireland. Kilbrook spring (Co. Kildare) has the highest recorded temperatures for any thermal spring in Ireland (maximum of 25.0 °C), and St. Gorman's Well (Co. Meath) has a complex and variable temperature profile (maximum of 21.8 °C). These temperatures are elevated with respect to average Irish groundwater temperatures (9.5 - 10.5 °C), and represent a geothermal energy potential, which is currently under evaluation. A multi-disciplinary investigation based upon audio-magnetotelluric (AMT) surveys, time-lapse temperature and chemistry measurements, and hydrochemical analysis, has been undertaken with the aims of investigating the provenance of the thermal groundwater and characterising the geological structures facilitating groundwater circulation in the bedrock. The hydrochemical analysis indicates that the thermal waters flow within the limestones of the Dublin Basin, and there is evidence that Kilbrook spring receives a contribution from deep-basinal fluids. The time-lapse temperature, electrical conductivity and water level records for St. Gorman's Well indicate a strongly non-linear response to recharge inputs to the system, suggestive of fluid flow in karst conduits. The 3-D electrical resistivity models of the subsurface revealed two types of geological structure beneath the springs; (1) Carboniferous normal faults, and (2) Cenozoic strike-slip faults. These structures are dissolutionally enhanced, particularly where they intersect. The karstification of these structures, which extend to depths of at least 500 m, has provided conduits that facilitate the operation of a relatively deep hydrothermal circulation pattern (likely estimated depths between 240 and 1,000 m) within the Dublin

Geologic framework and hydrogeologic characteristics of the Edwards aquifer outcrop (Barton Springs segment), northeastern Hays and southwestern Travis Counties, Texas

USGS Publications Warehouse

Small, Ted A.; Hanson, John A.; Hauwert, Nico M.

1996-01-01

In the Barton Springs segment of the Edwards aquifer, the aquifer probably is most vulnerable to surface contamination in the rapidly urbanizing areas on the Edwards aquifer outcrop. Contamination can result from spills or leakage of hazardous materials; or runoff on the intensely faulted and fractured, karstic limestone outcrops characteristic of the recharge zone.

Deep geothermal processes acting on faults and solid tides in coastal Xinzhou geothermal field, Guangdong, China

NASA Astrophysics Data System (ADS)

Lu, Guoping; Wang, Xiao; Li, Fusi; Xu, Fangyiming; Wang, Yanxin; Qi, Shihua; Yuen, David

2017-03-01

This paper investigated the deep fault thermal flow processes in the Xinzhou geothermal field in the Yangjiang region of Guangdong Province. Deep faults channel geothermal energy to the shallow ground, which makes it difficult to study due to the hidden nature. We conducted numerical experiments in order to investigate the physical states of the geothermal water inside the fault zone. We view the deep fault as a fast flow path for the thermal water from the deep crust driven up by the buoyancy. Temperature measurements at the springs or wells constrain the upper boundary, and the temperature inferred from the Currie temperature interface bounds the bottom. The deepened boundary allows the thermal reservoir to revolve rather than to be at a fixed temperature. The results detail the concept of a thermal reservoir in terms of its formation and heat distribution. The concept also reconciles the discrepancy in reservoir temperatures predicted from both quartz and Na-K-Mg. The downward displacement of the crust increases the pressure at the deep ground and leads to an elevated temperature and a lighter water density. Ultimately, our results are a first step in implementing numerical studies of deep faults through geothermal water flows; future works need to extend to cases of supercritical states. This approach is applicable to general deep-fault thermal flows and dissipation paths for the seismic energy from the deep crust.

Fault finder

DOEpatents

Bunch, Richard H.

1986-01-01

A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master unit for processing to determine an accurate fault distance calculation.

Process-based monitoring and modeling of Karst springs - Linking intrinsic to specific vulnerability.

PubMed

Epting, Jannis; Page, Rebecca M; Auckenthaler, Adrian; Huggenberger, Peter

2018-06-01

The presented work illustrates to what extent field investigations as well as monitoring and modeling approaches are necessary to understand the high discharge dynamics and vulnerability of Karst springs. In complex settings the application of 3D geological models is essential for evaluating the vulnerability of Karst systems. They allow deriving information on catchment characteristics, as the geometry of aquifers and aquitards as well as their displacements along faults. A series of Karst springs in northwestern Switzerland were compared and Karst system dynamics with respect to qualitative and quantitative issues were evaluated. The main objective of the studies was to combine information of catchment characteristics and data from novel monitoring systems (physicochemical and microbiological parameters) to assess the intrinsic vulnerability of Karst springs to microbiological contamination with simulated spring discharges derived from numerical modeling (linear storage models). The numerically derived relation of fast and slow groundwater flow components enabled us to relate different sources of groundwater recharge and to characterize the dynamics of the Karst springs. Our study illustrates that comparably simple model-setups were able to reproduce the overall dynamic intrinsic vulnerability of several Karst systems and that one of the most important processes involved was the temporal variation of groundwater recharge (precipitation, evapotranspiration and snow melt). Furthermore, we make a first attempt on how to link intrinsic to specific vulnerability of Karst springs, which involves activities within the catchment area as human impacts from agriculture and settlements. Likewise, by a more detailed representation of system dynamics the influence of surface water, which is impacted by release events from storm sewers, infiltrating into the Karst system, could be considered. Overall, we demonstrate that our approach can be the basis for a more flexible and

Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices

USGS Publications Warehouse

Funk, Christopher C.; Hoell, Andrew; Shukla, Shraddhanand; Blade, Ileana; Liebmann, Brant; Roberts, Jason B.; Robertson, Franklin R.

2014-01-01

In southern Ethiopia, Eastern Kenya, and southern Somalia poor boreal spring rains in 1999, 2000, 2004, 2007, 2008, 2009 and 2011 contributed to severe food insecurity and high levels of malnutrition. Predicting rainfall deficits in this region on seasonal and decadal time frames can help decision makers support disaster risk reduction while guiding climate-smart adaptation and agricultural development. Building on recent research that links more frequent droughts to a stronger Walker Circulation, warming in the Indo-Pacific warm pool, and an increased western Pacific sea surface temperature (SST) gradient, we explore the dominant modes of East African rainfall variability, links between these modes and sea surface temperatures, and a simple index-based monitoring-prediction system suitable for drought early warning.

Jet-Suspended, Calcite-Ballasted Cyanobacterial Waterwarts in a Desert Spring

NASA Technical Reports Server (NTRS)

Pichel-Garcia, Ferran; Wade, Bman D.; Farmer, Jack D.

2002-01-01

We describe a population of colonial cyanobacteria (waterwarts) that develops as the dominant primary producer in a bottom-fed, warm spring in the Cuatro Cienegas karstic region of the Mexican Chihuahuan Desert. The centimeter-sized waterwarts were suspended within a central, conically shaped, 6-m deep well by upwelling waters. Waterwarts were built by an unicellular cyanobacterium and supported a community of epiphytic filamentous cyanobacteria and diatoms but were free of heterotrophic bacteria inside. Sequence analysis of genes revealed that this cyanobacterium is only distantly related to several strains of other unicellular teria Cyanothece, Waterwarts contained orderly arrangements of mineral made up of microcrystalline low-magnesium calcite with high levels of strontium and sulfur. Waterwarts were 95.9% (v/v) glycan, 2.8% cells, and 1.3% mineral grains and had a buoyant density of 1.034 kg/L. An analysis of the hydrological properties of the spring well and the waterwarts demonstrated that both large colony size and the presence of controlled amounts of mineral ballast are required to prevent the population from being washed out of the well. The unique hydrological characteristics of the spring have likely selected for both traits. The mechanisms by which controlled nucleation of extracellular calcite is achieved remain to be explored.

Hot springs, geochemistry, and regional heat flow of northcentral Mexico

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

Swanberg, C.A.; Marvin, P.R.; Salazar S., L.

1981-10-01

To date we have found, sampled and performed chemical analyses on 21 hot springs (T > 30/sup 0/C), 4 hot wells (T > 30/sup 0/C) and 15 warm springs (T = 25 to 30/sup 0/C) from the states of Chihuahua, Coahuila and Sonora, Mexico. Also in order to establish background chemistry, an additional 250 cold wells and springs (T = 12 to 25/sup 0/C) were sampled and analyzed and several hundred water analyses from the several thousand provided by various Mexican agencies were included. The technique of silica geothermometry was used to estimate the regional heat flow of northcentral Mexico.more » Both the traditional heat flow and the silica heat flow values are generally high and show considerable scatter as is typical of areas having Tertiary and Quaternary volcanic and tectonic activity. Specific areas of high heat flow (> 2.5 HFU) include the Presidio and Los Muertos Bolsons, the Cuidad Chihuahua-Chuatemoc area, the Delicias area, and the area south of the San Bernardino Bolson of southeast Arizona. Areas of lower heat flow (2.0 to 2.5 HFU) include the Jimenez-Camargo region and the area between the Los Muertos and Presidio Bolsons.« less

Fault Zone Permeability Decrease Following Large Earthquakes in a Hydrothermal System

NASA Astrophysics Data System (ADS)

Shi, Zheming; Zhang, Shouchuan; Yan, Rui; Wang, Guangcai

2018-02-01

Seismic wave shaking-induced permeability enhancement in the shallow crust has been widely observed. Permeability decrease, however, is seldom reported. In this study, we document coseismic discharge and temperature decrease in a hot spring following the 1996 Lijiang Mw 7.0 and the 2004 Mw 9.0 earthquakes in the Balazhang geothermal field. We use three different models to constrain the permeability change and the mechanism of coseismic discharge decrease, and we use an end-member mixing model for the coseismic temperature change. Our results show that the earthquake-induced permeability decrease in the fault zone reduced the recharge from deep hot water, which may be the mechanism that explains the coseismic discharge and temperature responses. The changes in the hot spring response reflect the dynamic changes in the hydrothermal system; in the future, the earthquake-induced permeability decrease should be considered when discussing controls on permeability.

The Sorong Fault Zone, Indonesia: Mapping a Fault Zone Offshore

NASA Astrophysics Data System (ADS)

Melia, S.; Hall, R.

2017-12-01

The Sorong Fault Zone is a left-lateral strike-slip fault zone in eastern Indonesia, extending westwards from the Bird's Head peninsula of West Papua towards Sulawesi. It is the result of interactions between the Pacific, Caroline, Philippine Sea, and Australian Plates and much of it is offshore. Previous research on the fault zone has been limited by the low resolution of available data offshore, leading to debates over the extent, location, and timing of movements, and the tectonic evolution of eastern Indonesia. Different studies have shown it north of the Sula Islands, truncated south of Halmahera, continuing to Sulawesi, or splaying into a horsetail fan of smaller faults. Recently acquired high resolution multibeam bathymetry of the seafloor (with a resolution of 15-25 meters), and 2D seismic lines, provide the opportunity to trace the fault offshore. The position of different strands can be identified. On land, SRTM topography shows that in the northern Bird's Head the fault zone is characterised by closely spaced E-W trending faults. NW of the Bird's Head offshore there is a fold and thrust belt which terminates some strands. To the west of the Bird's Head offshore the fault zone diverges into multiple strands trending ENE-WSW. Regions of Riedel shearing are evident west of the Bird's Head, indicating sinistral strike-slip motion. Further west, the ENE-WSW trending faults turn to an E-W trend and there are at least three fault zones situated immediately south of Halmahera, north of the Sula Islands, and between the islands of Sanana and Mangole where the fault system terminates in horsetail strands. South of the Sula islands some former normal faults at the continent-ocean boundary with the North Banda Sea are being reactivated as strike-slip faults. The fault zone does not currently reach Sulawesi. The new fault map differs from previous interpretations concerning the location, age and significance of different parts of the Sorong Fault Zone. Kinematic

Moisture increase in response to high-altitude warming evidenced by tree-rings on the southeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Li, Jinbao; Shi, Jiangfeng; Zhang, David D.; Yang, Bao; Fang, Keyan; Yue, Pak Hong

2017-01-01

Rapid warming has been observed in the high-altitude areas around the globe, but the implications on moisture change are not fully understood. Here we use tree-rings to reveal common moisture change on the southeastern Tibetan Plateau (TP) during the past five centuries, and show that regional moisture change in late spring to early summer (April-June) is closely related to large-scale temperature anomaly over the TP, with increased moisture coincident with periods of high temperature. The most recent pluvial during the 1990s-2000s is likely the wettest for the past five centuries, which coincides with the warmest period on the TP during the past millennium. Dynamic analysis reveals that vertical air convection is enhanced in response to anomalous TP surface warming, leading to an increase in lower-tropospheric humidity and effective precipitation over the southeastern TP. The coherent warm-wet relationship identified in both tree-rings and dynamic analysis implies a generally wetter condition on the southeastern TP under future warming.

Seismomagnetic observation during the 8 July 1986 magnitude 5.9 North Palm Springs earthquake

USGS Publications Warehouse

Johnston, M.J.S.; Mueller, R.J.

1987-01-01

A differentially connected array of 24 proton magnetometers has operated along the San Andreas fault since 1976. Seismomagnetic offsets of 1.2 and 0.3 nanotesla were observed at epicentral distances of 3 and 9 kilometers, respectively, after the 8 July 1986 magnitude 5.9 North Palm Springs earthquake. These seismomagnetic observations are the first obtained of this elusive but long-anticipated effect. The data are consistent with a seismomagnetic model of the earthquake for which right-lateral rupture of 20 centimeters is assumed on a 16-kilometer segment of the Banning fault between the depths of 3 and 10 kilometers in a region with average magnetization of 1 ampere per meter. Alternative explanations in terms of electrokinetic effects and earthquake-generated electrostatic charge redistribution seem unlikely because the changes are permanent and complete within a 20-minute period.

Plio-Pleistocene synsedimentary fault compartments, foundation for the eastern Olduvai Basin paleoenvironmental mosaic, Tanzania.

PubMed

Stollhofen, Harald; Stanistreet, Ian G

2012-08-01

Normal faults displacing Upper Bed I and Lower Bed II strata of the Plio-Pleistocene Lake Olduvai were studied on the basis of facies and thickness changes as well as diversion of transport directions across them in order to establish criteria for their synsedimentary activity. Decompacted differential thicknesses across faults were then used to calculate average fault slip rates of 0.05-0.47 mm/yr for the Tuff IE/IF interval (Upper Bed I) and 0.01-0.13 mm/yr for the Tuff IF/IIA section (Lower Bed II). Considering fault recurrence intervals of ~1000 years, fault scarp heights potentially achieved average values of 0.05-0.47 m and a maximum value of 5.4 m during Upper Bed I, which dropped to average values of 0.01-0.13 m and a localized maximum of 0.72 m during Lower Bed II deposition. Synsedimentary faults were of importance to the form and paleoecology of landscapes utilized by early hominins, most traceably and provably Homo habilis as illustrated by the recurrent density and compositional pattern of Oldowan stone artifact assemblage variation across them. Two potential relationship factors are: (1) fault scarp topographies controlled sediment distribution, surface, and subsurface hydrology, and thus vegetation, so that a resulting mosaic of microenvironments and paleoecologies provided a variety of opportunities for omnivorous hominins; and (2) they ensured that the most voluminous and violent pyroclastic flows from the Mt. Olmoti volcano were dammed and conduited away from the Olduvai Basin depocenter, when otherwise a single or set of ignimbrite flows might have filled and devastated the topography that contained the central lake body. In addition, hydraulically active faults may have conduited groundwater, supporting freshwater springs and wetlands and favoring growth of trees. Copyright © 2011 Elsevier Ltd. All rights reserved.

Experimental Fault Diagnosis in Systems Containing Finite Elements of Plate of Kirchoff by Using State Observers Methodology

NASA Astrophysics Data System (ADS)

Alegre, D. M.; Koroishi, E. H.; Melo, G. P.

2015-07-01

This paper presents a methodology for detection and localization of faults by using state observers. State Observers can rebuild the states not measured or values from points of difficult access in the system. So faults can be detected in these points without the knowledge of its measures, and can be track by the reconstructions of their states. In this paper this methodology will be applied in a system which represents a simplified model of a vehicle. In this model the chassis of the car was represented by a flat plate, which was divided in finite elements of plate (plate of Kirchoff), in addition, was considered the car suspension (springs and dampers). A test rig was built and the developed methodology was used to detect and locate faults on this system. In analyses done, the idea is to use a system with a specific fault, and then use the state observers to locate it, checking on a quantitative variation of the parameter of the system which caused this crash. For the computational simulations the software MATLAB was used.

North Siberian Permafrost reveals Holocene Arctic Winter Warming

NASA Astrophysics Data System (ADS)

Meyer, H.; Opel, T.; Laepple, T.; Alexander, D.; Hoffmann, K.; Werner, M.

2014-12-01

The Arctic climate has experienced a major warming over the past decades, which is unprecedented in the last 2000 yrs. There are, however, still major uncertainties about the temperature evolution during the Holocene. Most proxy reconstructions suggest a cooling in mid-and late Holocene (e.g. Wanner, 2008), whereas climate model simulations show only weak changes or even a moderate warming (e.g. Lohmann et al., 2013). In this study, we used ice wedges as promising permafrost climate archive studied by stable water isotope methods. Ice wedges may be identified by vertically oriented foliations, and they form by the repeated filling of winter thermal contraction cracks by snow melt water in spring. Therefore, the isotopic composition of wedge ice may be attributed to the climate conditions of the cold season (i.e. winter and spring). 42 samples of organic material enclosed in ice wedges have been directly dated by Radiocarbon methods. Here, we present the first terrestrial stable oxygen isotope record of Holocene winter temperatures in up to centennial-scale resolution based on permafrost ice wedges (Lena River Delta; Siberian Arctic). The Lena ice-wedge record shows that the recent isotopic temperatures are the highest of the past 7000 years. Despite similarities to Arctic temperature reconstructions of the last two millennia (Kaufman et al., 2009), it suggests a winter warming throughout the mid and late Holocene, opposite to most existing other proxy records (Wanner, 2008). This apparent contradiction can be explained by the seasonality of the ice-wedge genesis in combination with orbital and greenhouse gas forcing and is consistent with climate model simulations. We conclude that the present model-data mismatch might be an artefact of the summer bias of the existing proxy records and thus, our record helps to reconcile the understanding of the northern hemisphere Holocene temperature evolution. This is particular true for the Russian Arctic significantly

GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany).

PubMed

Berberich, Gabriele; Schreiber, Ulrich

2013-05-17

In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO₂, Helium, Radon and H₂S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

Fault zone hydrogeology

NASA Astrophysics Data System (ADS)

Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

2013-12-01

Deformation along faults in the shallow crust (< 1 km) introduces permeability heterogeneity and anisotropy, which has an important impact on processes such as regional groundwater flow, hydrocarbon migration, and hydrothermal fluid circulation. Fault zones have the capacity to be hydraulic conduits connecting shallow and deep geological environments, but simultaneously the fault cores of many faults often form effective barriers to flow. The direct evaluation of the impact of faults to fluid flow patterns remains a challenge and requires a multidisciplinary research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and

Climate change and bird reproduction: warmer springs benefit breeding success in boreal forest grouse.

PubMed

Wegge, Per; Rolstad, Jørund

2017-11-15

Global warming is predicted to adversely affect the reproduction of birds, especially in northern latitudes. A recent study in Finland inferred that declining populations of black grouse, Tetrao tetrix , could be attributed to advancement of the time of mating and chicks hatching too early-supporting the mismatch hypothesis. Here, we examine the breeding success of sympatric capercaillie, T. urogallus, and black grouse over a 38-year period in southeast Norway. Breeding season temperatures increased, being most pronounced in April. Although the onset of spring advanced nearly three weeks, the peak of mating advanced only 4-5 days. In contrast to the result of the Finnish study, breeding success increased markedly in both species (capercaillie: 62%, black grouse: 38%). Both brood frequency and brood size increased during the study period, but significantly so only for brood frequency in capercaillie. Whereas the frequency of capercaillie broods was positively affected by rising temperatures, especially during the pre-hatching period, this was not the case in black grouse. Brood size, on the other hand, increased with increasing post-hatching temperatures in both species. Contrary to the prediction that global warming will adversely affect reproduction in boreal forest grouse, our study shows that breeding success was enhanced in warmer springs. © 2017 The Authors.

Tectonic geomorphology and paleoseismology of strike-slip faults in Jamaica: Implications for distribution of strain and seismic hazard along the southern edge of the Gonave microplate

NASA Astrophysics Data System (ADS)

Koehler, R. D.; Mann, P.; Brown, L. A.

2009-12-01

The east-west, left lateral strike-slip fault system forming the southern edge of the Gonave microplate crosses the110-km-long and 70-km-wide island of Jamaica. GPS measurements in the northeastern Caribbean are supportive of the microplate interpretation and indicate that ~ half of the Caribbean-North America left-lateral plate motion (8-14 mm/yr) is carried by the Plantain Garden (PGFZ) and associated faults in Jamaica. We performed Neotectonic mapping of the Plantain Garden fault along the southern rangefront of the Blue Mountains and conducted a paleoseismic study of the fault at Morant River. Between Holland Bay and Morant River, the fault is characterized by a steep, faceted, linear mountain front, prominent linear valleys and depressions, shutter ridges, and springs. At the eastern end of the island, the PGFZ is characterized by a left-stepping fault geometry that includes a major, active hot spring. The river cut exposure at Morant River exposes a 1.5-m-wide, sub-vertical fault zone juxtaposing sheared alluvium and faulted Cretaceous basement rocks. This section is overlain by an, unfaulted 3-m-thick fluvial terrace inset into a late Pleistocene terrace that is culturally modified. Upward fault terminations indicate the occurrence of three paleoearthquakes that occurred prior to deposition of the flat lying inset terrace around 341-628 cal yr BP. At this time, our radiocarbon results suggest that we can rule out the PGFZ as the source of the 1907 Kingston earthquake 102 years ago, as well as, the 1692 event that destroyed Port Royal 317 years ago and produced a major landslide at Yallahs. Pending OSL ages will constrain the age of the penultimate and most recent ruptures. Gently to steeply dipping rocks as young as Pliocene exposed in roadcuts within the low coastal hills south of and parallel to the Plantain Garden fault may indicate active folding and blind thrust faulting. These structures are poorly characterized and may accommodate an unknown amount of

Interactions between Polygonal Normal Faults and Larger Normal Faults, Offshore Nova Scotia, Canada

NASA Astrophysics Data System (ADS)

Pham, T. Q. H.; Withjack, M. O.; Hanafi, B. R.

2017-12-01

Polygonal faults, small normal faults with polygonal arrangements that form in fine-grained sedimentary rocks, can influence ground-water flow and hydrocarbon migration. Using well and 3D seismic-reflection data, we have examined the interactions between polygonal faults and larger normal faults on the passive margin of offshore Nova Scotia, Canada. The larger normal faults strike approximately E-W to NE-SW. Growth strata indicate that the larger normal faults were active in the Late Cretaceous (i.e., during the deposition of the Wyandot Formation) and during the Cenozoic. The polygonal faults were also active during the Cenozoic because they affect the top of the Wyandot Formation, a fine-grained carbonate sedimentary rock, and the overlying Cenozoic strata. Thus, the larger normal faults and the polygonal faults were both active during the Cenozoic. The polygonal faults far from the larger normal faults have a wide range of orientations. Near the larger normal faults, however, most polygonal faults have preferred orientations, either striking parallel or perpendicular to the larger normal faults. Some polygonal faults nucleated at the tip of a larger normal fault, propagated outward, and linked with a second larger normal fault. The strike of these polygonal faults changed as they propagated outward, ranging from parallel to the strike of the original larger normal fault to orthogonal to the strike of the second larger normal fault. These polygonal faults hard-linked the larger normal faults at and above the level of the Wyandot Formation but not below it. We argue that the larger normal faults created stress-enhancement and stress-reorientation zones for the polygonal faults. Numerous small, polygonal faults formed in the stress-enhancement zones near the tips of larger normal faults. Stress-reorientation zones surrounded the larger normal faults far from their tips. Fewer polygonal faults are present in these zones, and, more importantly, most polygonal faults

Spring snow albedo feedback in daily data over Russia: Comparing in-situ measurements with reanalysis products.

NASA Astrophysics Data System (ADS)

Wegmann, M.; Zolina, O.; Jacobi, H. W.

2016-12-01

Global warming is enhanced at high northern latitudes where the Arctic surface air temperature has risen at twice the rate of the global average in recent decades - a feature called Arctic amplification. This recent Arctic warming signal likely results from several factors such as the albedo feedback due to a diminishing cryosphere, enhanced poleward atmospheric and oceanic heat transport, and changes in humidity. Surface albedo feedback is stating that the additional amount of shortwave radiation at the top of the atmosphere decreases with decreasing surface albedo whereas surface air temperature increases with decreasing surface albedo. It is considered a positive feedback in that an initial warming perturbation than kicks off a strengthening warming. Looking at the Northern Hemisphere with its large landmasses, snow albedo feedback is especially strong since most of these landmasses experience snow cover during boreal wintertime. Unfortunately, so far there remains a lack of reliable observational data over large parts of the cryosphere. Satellite products cover large parts of the NH, however lack high temporal resolution and have problems with large solar zenith angles as well as over complex terrain (eg. Wang et al. 2014). Our analysis focuses at the Russian territory where we utilize in-situ radiation and snow depth measurements. We found 50 stations which measure both variables on a daily basis for the period 2000-2013. Since Hall (2004) found that 50% of the notal NH snow albedo feedback caused by global warming occurs during NH spring, we focus on the transition period of March to June (MAMJ). Thackeray & Fletcher 2006 compared albedo feedback processes CMIP3 and CMIP5 model families and found while the models represent the feedback process accurately, there are still inherent biases and outdated parameterizations. Therefore we use the daily observations and state of the art reanalysis products to 1) evaluate reanalysis and model products in respect to

ENSO amplitude changes due to greenhouse warming in CMIP5: Role of mean tropical precipitation in the 20th centur

NASA Astrophysics Data System (ADS)

Ham, Yoo-Geun; Kug, Jong-Seong

2017-04-01

The relationship between the present-climate climatology and those of ENSO amplitude change under global warming in the CMIP5 models is examined. The models with increased ENSO amplitude under greenhouse warming tend to simulate a 20th century stronger climatological ITCZ and SPCZ over the central-eastern Pacific that are located further away from the equator during boreal spring. The budget analysis using moisture equation indicates that those climatological differences lead to stronger positive climatological precipitation change over the off-equatorial central-eastern Pacific under greenhouse warming. The stronger positive climatological precipitation change enhances the air-sea coupling strength over the central-eastern Pacific, which results in the increase of the ENSO amplitude.

Extreme Winter/Early-Spring Temperature Anomalies in Central Europe

NASA Technical Reports Server (NTRS)

Otterman, Joseph; Atlas, Robert; Ardizzone, Joseph; Brakke, Thomas; Chou, Shu-Hsien; Jusem, Juan Carlos; Glantz, Michael; Rogers, Jeff; Sud, Yogesh; Susskind, Joel

2000-01-01

Extreme seasonal fluctuations of the surface-air temperature characterize the climate of central Europe, 45-60 deg North Temperature difference between warm 1990 and cold 1996 in the January-March period, persisting for more than two weeks at a time, amounted to 18 C for extensive areas. These anomalies in the surface-air temperature stem in the first place from differences in the low level flow from the eastern North-Atlantic: the value of the Index 1na of southwesterlies over the eastern North-Atlantic was 8.0 m/s in February 1990, but only 2.6 m/ s in February 1996. The primary forcing by warm advection to positive anomalies in monthly mean surface temperature produced strong synoptic-scale uplift at the 700 mb level over some regions in Europe. The strong uplift contributed in 1990 to a much larger cloud-cover over central Europe, which reduced heat-loss to space (greenhouse effect). Thus, spring arrived earlier than usual in 1990, but later than usual in 1996.

Fault diagnosis

NASA Technical Reports Server (NTRS)

Abbott, Kathy

1990-01-01

The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to

Diverse subaerial and sublacustrine hot spring settings of the Cerro Negro epithermal system (Jurassic, Deseado Massif), Patagonia, Argentina

NASA Astrophysics Data System (ADS)

Guido, Diego M.; Campbell, Kathleen A.

2012-06-01

The Late Jurassic (~ 150 Ma) Cerro Negro volcanic-epithermal-geothermal system (~ 15 km2 area), Deseado Massif, Patagonia, Argentina, includes two inferred volcanic emission centers characterized by rhyolitic domes linked along NW-SE regional faults that are associated with deeper level Au/Ag mineralization to the NW, and with shallow epithermal quartz veins and mainly travertine surface hot spring manifestations to the SE. Some travertines are silica-replaced, and siliceous and mixed silica-carbonate geothermal deposits also are found. Five hot spring-related facies associations were mapped in detail, which show morphological and textural similarities to Pleistocene-Recent geothermal deposits at Yellowstone National Park (U.S.A.), the Kenya Rift Valley, and elsewhere. They are interpreted to represent subaerial travertine fissure ridge/mound deposits (low-flow spring discharge) and apron terraces (high-flow spring discharge), as well as mixed silica-carbonate lake margin and shallow lake terrace vent-conduit tubes, stromatolitic mounds, and volcano-shaped cones. The nearly 200 mapped fossil vent-associated deposits at Cerro Negro are on a geographical and numerical scale comparable with subaerial and sublacustrine hydrothermal vents at Mammoth Hot Springs, and affiliated with Yellowstone Lake, respectively. Overall, the Cerro Negro geothermal system yields paleoenvironmentally significant textural details of variable quality, owing to both the differential preservation potential of particular subaerial versus subaqueous facies, as well as to the timing and extent of carbonate diagenesis and silica replacement of some deposits. For example, the western fault associated with the Eureka epithermal quartz vein facilitated early silicification of the travertine deposits in the SE volcanic emission center, thereby preserving high-quality, microbial macro- and micro-textures of this silica-replaced "pseudosinter." Cerro Negro provides an opportunity to reconstruct

Winter warming as an important co-driver for Betula nana growth in western Greenland during the past century.

PubMed

Hollesen, Jørgen; Buchwal, Agata; Rachlewicz, Grzegorz; Hansen, Birger U; Hansen, Marc O; Stecher, Ole; Elberling, Bo

2015-06-01

Growing season conditions are widely recognized as the main driver for tundra shrub radial growth, but the effects of winter warming and snow remain an open question. Here, we present a more than 100 years long Betula nana ring-width chronology from Disko Island in western Greenland that demonstrates a highly significant and positive growth response to both summer and winter air temperatures during the past century. The importance of winter temperatures for Betula nana growth is especially pronounced during the periods from 1910-1930 to 1990-2011 that were dominated by significant winter warming. To explain the strong winter importance on growth, we assessed the importance of different environmental factors using site-specific measurements from 1991 to 2011 of soil temperatures, sea ice coverage, precipitation and snow depths. The results show a strong positive growth response to the amount of thawing and growing degree-days as well as to winter and spring soil temperatures. In addition to these direct effects, a strong negative growth response to sea ice extent was identified, indicating a possible link between local sea ice conditions, local climate variations and Betula nana growth rates. Data also reveal a clear shift within the last 20 years from a period with thick snow depths (1991-1996) and a positive effect on Betula nana radial growth, to a period (1997-2011) with generally very shallow snow depths and no significant growth response towards snow. During this period, winter and spring soil temperatures have increased significantly suggesting that the most recent increase in Betula nana radial growth is primarily triggered by warmer winter and spring air temperatures causing earlier snowmelt that allows the soils to drain and warm quicker. The presented results may help to explain the recently observed 'greening of the Arctic' which may further accelerate in future years due to both direct and indirect effects of winter warming. © 2015 John Wiley & Sons

1. LOOKING NORTH, SHOWING IODINE SPRING (FOREGROUND), SALT SULPHUR SPRING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. LOOKING NORTH, SHOWING IODINE SPRING (FOREGROUND), SALT SULPHUR SPRING (LEFT BACKGROUND), AND TWIN COTTAGES (UPPER RIGHT) (4 x 5 negative; 5 x 7 print) - Salt Sulpher Springs, U.S. Route 219, Salt Sulphur Springs, Monroe County, WV

Groundwater flow cycling between a submarine spring and an inland fresh water spring.

PubMed

Davis, J Hal; Verdi, Richard

2014-01-01

Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Groundwater flow cycling between a submarine spring and an inland fresh water spring

USGS Publications Warehouse

Davis, J. Hal; Verdi, Richard

2014-01-01

Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half.

3D ground‐motion simulations of Mw 7 earthquakes on the Salt Lake City segment of the Wasatch fault zone: Variability of long‐period (T≥1  s) ground motions and sensitivity to kinematic rupture parameters

USGS Publications Warehouse

Moschetti, Morgan P.; Hartzell, Stephen; Ramirez-Guzman, Leonardo; Frankel, Arthur; Angster, Stephen J.; Stephenson, William J.

2017-01-01

We examine the variability of long‐period (T≥1  s) earthquake ground motions from 3D simulations of Mw 7 earthquakes on the Salt Lake City segment of the Wasatch fault zone, Utah, from a set of 96 rupture models with varying slip distributions, rupture speeds, slip velocities, and hypocenter locations. Earthquake ruptures were prescribed on a 3D fault representation that satisfies geologic constraints and maintained distinct strands for the Warm Springs and for the East Bench and Cottonwood faults. Response spectral accelerations (SA; 1.5–10 s; 5% damping) were measured, and average distance scaling was well fit by a simple functional form that depends on the near‐source intensity level SA0(T) and a corner distance Rc:SA(R,T)=SA0(T)(1+(R/Rc))−1. Period‐dependent hanging‐wall effects manifested and increased the ground motions by factors of about 2–3, though the effects appeared partially attributable to differences in shallow site response for sites on the hanging wall and footwall of the fault. Comparisons with modern ground‐motion prediction equations (GMPEs) found that the simulated ground motions were generally consistent, except within deep sedimentary basins, where simulated ground motions were greatly underpredicted. Ground‐motion variability exhibited strong lateral variations and, at some sites, exceeded the ground‐motion variability indicated by GMPEs. The effects on the ground motions of changing the values of the five kinematic rupture parameters can largely be explained by three predominant factors: distance to high‐slip subevents, dynamic stress drop, and changes in the contributions from directivity. These results emphasize the need for further characterization of the underlying distributions and covariances of the kinematic rupture parameters used in 3D ground‐motion simulations employed in probabilistic seismic‐hazard analyses.

Conditions leading to the unprecedented low Antarctic sea ice extent during the 2016 austral spring season

NASA Astrophysics Data System (ADS)

Stuecker, Malte F.; Bitz, Cecilia M.; Armour, Kyle C.

2017-09-01

The 2016 austral spring was characterized by the lowest Southern Hemisphere (SH) sea ice extent seen in the satellite record (1979 to present) and coincided with anomalously warm surface waters surrounding most of Antarctica. We show that two distinct processes contributed to this event: First, the extreme El Niño event peaking in December-February 2015/2016 contributed to pronounced extratropical SH sea surface temperature and sea ice extent anomalies in the eastern Ross, Amundsen, and Bellingshausen Seas that persisted in part until the following 2016 austral spring. Second, internal unforced atmospheric variability of the Southern Annular Mode promoted the exceptional low sea ice extent in November-December 2016. These results suggest that a combination of tropically forced and internal SH atmospheric variability contributed to the unprecedented sea ice decline during the 2016 austral spring, on top of a background of slow changes expected from greenhouse gas and ozone forcing.

78 FR 34090 - Lois Von Morganroth; Shiloh Warm Springs Ranch, LLC; Notice of Application for Transfer of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-06

... Springs Ranch, LLC (transferee) filed an application for the transfer of license for the L & M Angus Ranch..., Idaho. Applicants seek Commission approval to transfer the license for the L & M Angus Ranch Project...

Post-Late Glacial calcareous tufas from the Kurai fault zone (Southeastern Gorny Altai, Russia)

NASA Astrophysics Data System (ADS)

Kokh, Svetlana N.; Sokol, Ella V.; Deev, Evgeny V.; Ryapolova, Yuliya M.; Rusanov, Gennady G.; Tomilenko, Anatoliy A.; Bul'bak, Taras A.

2017-06-01

Calcareous tufa deposits have been discovered in the Chibitka River valley near Lake Cheybek-Kohl, at the junction of the Kurai and Teletsk-Kurai large active faults in the southeastern Gorny Altai, Russia, at an altitude of 1800-2000 m. Fossil tufa is composed of calcite and cements Holocene grey colluvium and glacial till deposited by the Late Glacial Chibitka Glacier. Current tufa precipitation has been observed from a low-flow spring with cold (10 °C) HCO3-SO4-Ca-Mg water, pH = 6.86. The stable isotope composition of spring water is - 5.8‰ VPDB δ13C of dissolved inorganic carbon and - 14.5‰ VSMOW δ18O. Modern tufa consists of thin laminated Mg-calcite and Sr-aragonite crusts, with abundant algae and biofilms on their surfaces. Both modern and fossil tufas are depleted in REE (a total of 0.40-16.4 ppm and 0.40-3.80 ppm, respectively) and share similar PAAS-normalised REE + Y spectra with HREE enrichment and slight progressive LREE depletion. The modern tufas show positive δ13C values of 0.1‰ to 0.9‰ VPDB while the fossil ones have an isotopically lighter composition of δ13C = - 4.1‰ to - 1.9‰ VPDB; the δ18O range is very narrow (- 13.0 to - 13.8‰ VPDB). Both stable isotope and trace-element signatures (including REE patterns) of the tufas indicate precipitation from cold groundwaters subjected to prolonged interaction with a carbonate aquifer (the Baratal Group of limestone and dolostone) in a cold continental climate similar to the present conditions. Tufa deposition in the Lake Cheybek-Kohl area began with the onset of post-Late Glacial global warming and permafrost degradation. Unlike the fossil tufa formation, current precipitation of freshwater carbonates has been microbially mediated. The discovered tufa deposits provide new palaeoclimatic and active tectonic proxies in the southeastern Gorny Altai.

A New Kinematic Model for Polymodal Faulting: Implications for Fault Connectivity

NASA Astrophysics Data System (ADS)

Healy, D.; Rizzo, R. E.

2015-12-01

Conjugate, or bimodal, fault patterns dominate the geological literature on shear failure. Based on Anderson's (1905) application of the Mohr-Coulomb failure criterion, these patterns have been interpreted from all tectonic regimes, including normal, strike-slip and thrust (reverse) faulting. However, a fundamental limitation of the Mohr-Coulomb failure criterion - and others that assume faults form parallel to the intermediate principal stress - is that only plane strain can result from slip on the conjugate faults. However, deformation in the Earth is widely accepted as being three-dimensional, with truly triaxial stresses and strains. Polymodal faulting, with three or more sets of faults forming and slipping simultaneously, can generate three-dimensional strains from truly triaxial stresses. Laboratory experiments and outcrop studies have verified the occurrence of the polymodal fault patterns in nature. The connectivity of polymodal fault networks differs significantly from conjugate fault networks, and this presents challenges to our understanding of faulting and an opportunity to improve our understanding of seismic hazards and fluid flow. Polymodal fault patterns will, in general, have more connected nodes in 2D (and more branch lines in 3D) than comparable conjugate (bimodal) patterns. The anisotropy of permeability is therefore expected to be very different in rocks with polymodal fault patterns in comparison to conjugate fault patterns, and this has implications for the development of hydrocarbon reservoirs, the genesis of ore deposits and the management of aquifers. In this contribution, I assess the published evidence and models for polymodal faulting before presenting a novel kinematic model for general triaxial strain in the brittle field.

Springs as hydrologic refugia in a changing climate? A remote sensing approach

USGS Publications Warehouse

Cartwright, Jennifer M.; Johnson, Henry M.

2018-01-01

Spring‐fed wetlands are ecologically important habitats in arid and semi‐arid regions. Springs have been suggested as possible hydrologic refugia from droughts and climate change; however, springs that depend on recent precipitation or snowmelt for recharge may be vulnerable to warming and drought intensification. Springs that are expected to maintain their ecohydrologic function in a warmer, drier climate may be priorities for conservation and restoration. Identifying such springs is difficult because many springs lack hydrologic records of adequate temporal extent and resolution to assess their resilience to water cycle changes. This study demonstrates proof‐of‐concept for the assessment of certain spring types (i.e., helocrene, hypocrene, and hillslope springs) in terms of hydrologic and ecological resilience to climatic water stress using freely available remote‐sensing and climate data. We used the Normalized Difference Vegetation Index (NDVI) from 1985 through 2011 to delineate surface‐moisture zones (SMZs) associated with 39 clusters of 172 springs in a montane sage‐steppe landscape in southeastern Oregon, USA. We developed and synthesized seven NDVI‐based indicators of SMZ resilience to interannual changes in water availability: (1) mean and (2) standard deviation of July NDVI; (3) mean difference in July NDVI and (4) difference in coefficient of variation for July NDVI between each SMZ and its surrounding watershed; (5) response of SMZ July NDVI to 90‐day antecedent precipitation; (6) response of SMZ July NDVI to the previous winter's snowpack; and (7) range of NDVI values from an exceptionally wet year followed by three dry years. Because all resilience indicators were highly inter‐correlated, we derived an overall metric of SMZ resilience using principal components analysis that accounted for 66% of total variance. This overall resilience score was positively correlated with SMZ elevation, slope, mean annual precipitation, and with