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Sample records for korea tectonic significance

  1. Middle Paleozoic metamorphism in the Hongseong area, South Korea, and tectonic significance for Paleozoic orogeny in northeast Asia

    NASA Astrophysics Data System (ADS)

    Oh, Chang-Whan; Imayama, Takeshi; Yi, Sang-Bong; Kim, Taeseong; Ryu, In-Chang; Jeon, Jimin; Yi, Keewook

    2014-12-01

    The Baekdong and Gwangcheon areas are located within the Hongseong collision belt of South Korea, and the discovery of late Permian-Triassic eclogites has confirmed this belt as an extension of the Qinling-Dabie-Sulu collision belt in China. The Qinling-Dabie-Sulu belt records a middle Paleozoic continental collision in addition to the late Permian-Triassic collision of the North and South China cratons. In this paper, we present evidence for middle Paleozoic igneous and metamorphic events in the Baekdong and Gwangcheon areas. Metabasites and meta-basaltic andesites in the Baekdong area originated in an arc tectonic setting at ca. 470-437 Ma, and underwent an intermediate-P/T metamorphism (6.2-8.2 kbar, 620-700 °C) at ca. 418-405 Ma. The meta-basaltic andesite in the Gwangcheon area underwent a high-pressure granulite facies metamorphism (close to the eclogite facies) at ca. 392-381 Ma. P-T values of 15.7-19.9 kbar and 860-890 °C were obtained for the peak metamorphism using conventional geothermobarometry, and conditions of 16-17 kbar and 870-920 °C were estimated by thermodynamic pseudosection analysis using the Perplex X program. Together with the late Permian-Triassic eclogites previously reported from the Hongseong area, these middle Paleozoic igneous activities that were related to subduction and metamorphism indicate that the Hongseong area underwent collision in the middle Paleozoic (418-381 Ma), in addition to the late Permian-Triassic collision, as recorded in the Qinling-Dabie-Sulu belt in China.

  2. Tectonic significance of serpentinites

    NASA Astrophysics Data System (ADS)

    Guillot, Stéphane; Schwartz, Stéphane; Reynard, Bruno; Agard, Philippe; Prigent, Cécile

    2015-04-01

    At plate boundaries, where deformation is localized along centimetre- to kilometre-scale shear zones, the influence of serpentinite on tectonic processes is linked to its unique rheological properties. In this paper we review the physical properties of serpentinites and their role in tectonic processes. At the ocean-continent transition, serpentinization weakens the upper mantle layer, promoting strain localization and allowing the normal faults in the distal margin to root at low angle. Similarly, at slow to ultra-slow spreading ridges, serpentinite is potentially very abundant at the seafloor and locally associated with domal structures. Extensional deformation is localized in a ~ 100 m thick shear zone at the footwall of detachment zones dominated by serpentine derived minerals. Within subduction zone, the depth of decoupling between the mantle wedge and the subducting slab corresponds to the stability depth of serpentine weak mineral. Dehydration of serpentine has also been hypothesized to play an important role in the origin of double seismic zones, however the exact mechanism through which dehydration promotes seismicity remains a matter of debate. During exhumation of high-pressure or ultrahigh-pressure rocks, the opposite trajectories of exhumation and subduction require a decoupling zone within the subducting slab. A serpentinized layer has the potential to become a decoupling zone between the oceanic crust and underlying lithosphere. The buoyancy of serpentinite also likely contributes to eclogite exhumation. Finally, along major strike-slip faults, serpentinites have been associated with fault creep, as well as low fault strength. The presence of serpentinite blocks along creeping segments of active faults worldwide is therefore likely to originate from fluids deriving from the progressive dehydration of the mantle wedge that move such bodies upward.

  3. 78 FR 51802 - Culturally Significant Objects Imported for Exhibition Determinations: “Silla: Korea's Golden...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Silla: Korea's Golden Kingdom... determine that the objects to be included in the exhibition ``Silla: Korea's Golden Kingdom,'' imported...

  4. Current regional stress field and the resultant crustal deformation in SE Korea and their tectonic implication

    NASA Astrophysics Data System (ADS)

    Kim, M. C.; Cho, H.; Son, M.

    2014-12-01

    To determine current regional stress field and to characterize the resultant crustal deformation in SE Korea, Quaternary fault, focal mechanism, and geotechnical in-situ stress data were synthetically analyzed. The Quaternary faults are extensively observed along major inherited fault zones and show compatible orientations with general trends of the inherited faults. Most of the Quaternary faults have a top-to-the-west thrust geometry and kinematics and show a tendency of upward-decreasing dip angle and upward-narrowing gouge zone. Slip-sense indicators and paleo-stress field reconstructions indicate that the faults resulted from reverse or transpressional faulting under an E-W compression. All the magnetic fabrics (AMS) of the fault gouges also indicate the prevailing reverse-slip faulting under an ENE-WNW compression. The dominant oblate magnetic fabrics parallel to fault plane and the degrees of anisotropy increasing in proportion to their oblatenesses indicate that the fabrics have formed by a progressive deformation due to continuous simple shear during the last reactivation stage as reverse faulting. The focal mechanism study in and around the Korean Peninsula show the horizontally clustered P-axes in ENE-WSW direction and the girdle-distributed T-axes in NNW trend. The geotechnical in-situ stress data in south Korea also show NE- or ENE-trending maximum horizontal stress. The current crustal deformation in Korea thus can be characterized by contractional structures produced under a regional E-W or ENE-WSW compression stress field, and most of the Quaternary faults resulted from the local re-activation of appropriately oriented inherited major faults. Considering the tectonic setting and structural features in Asia during the Neogene, the current stress regime is interpreted to have been caused by the cooperation of westward shallow subduction of Pacific Plate and collision of Indian and Eurasian continents since about 5-3.5 Ma.

  5. Intraplate volcanism influenced by distal subduction tectonics at Jeju Island, Republic of Korea

    NASA Astrophysics Data System (ADS)

    Brenna, Marco; Cronin, Shane J.; Kereszturi, Gábor; Sohn, Young Kwan; Smith, Ian E. M.; Wijbrans, Jan

    2015-01-01

    The drivers behind the inception of, and the variable, pulsatory eruption rates at distributed intraplate volcanic fields are not well understood. Such broad areas of monogenetic volcanism cover vast areas of the world and are often heavily populated. Reliable models to unravel their behaviour require robust spatio-temporal frameworks within the fields, but an analysis of the potential proximal and distal regional volcano-tectonic processes is also needed. Jeju Island (Republic of Korea) is a volcanic field that has been extensively drilled and dated. It is also located near one of the world's best-studied tectonic plate boundaries: the subduction zone in southwestern Japan, which generates the Ryukyu and SW Japan arcs. A new set of 40Ar/39Ar ages collected from cores penetrating the entire Jeju eruptive pile, along with geochemical information, is used to construct a temporal and volumetric model for the volcano's growth. The overall pattern indicates inception of volcanism at ~1.7 Ma, with an initial 1.2 Myr of low-rate activity, followed by over an order of magnitude rise over the last 0.5 Myr. The magma flux at Jeju correlates well with increased extension rates in the arc/backarc region. In particular, we infer that the increased trenchward mantle flow, caused by the greater rollback of the Philippine Sea Plate, activated pre-existing shear weaknesses in the mantle beneath Jeju, resulting in mantle upwelling and decompression melting that caused a change in compositions and an increase in eruption rates at Jeju. Thus, the volcanic activity of an intraplate field system can be modulated by regional subduction processes occurring more than 650 km away. This model may explain the frequent observation of pulsatory behaviour seen in many monogenetic volcanic fields worldwide that lie within 1,000 km of subduction zones.

  6. Tectonism

    NASA Image and Video Library

    2011-10-24

    This image from NASA 2001 Mars Odyssey spacecraft shows evidence of tectonic stresses that deform and fracture rocks and planetary surfaces. Right angles seen here are a good indication that the feature was formed by tectonic stresses.

  7. Tectonic significance of Silurain magmatism in the Canadian Appalachians

    SciTech Connect

    Whalen, J.B.; Bevier, M.L. )

    1990-05-01

    New U-Pb ages for granites from the New Brunswick part of the Canadian Appalachians indicate that >90% of the undeformed felsic plutons are Silurian and not Devonian as previously thought. Silurian igneous and sedimentary assemblages were recently recognized throughout the Canadian Appalachians, although the petrogenetic types of magmas as well as the grades of metamorphism and deformation vary widely. Our data support proposed tectonic models that suggest relatively continuous subduction and orogenic activity in the Canadian Appalachians from Middle Ordovician to Middle Devonian time.

  8. Tectonic significance of paleomagnetic data from northern Venezuela

    NASA Astrophysics Data System (ADS)

    Skerlec, G. M.; Hargraves, R. B.

    1980-10-01

    A paleomagnetic study, mostly of basic intrusive rocks of Cretaceous and Tertiary age from northern Venezuela, includes 153 samples from 31 sites, of which only 6 sites failed to give consistent results. Fifteen sites within the Caribbean Mountains have easterly declinations with shallow, mixed positive and negative inclinations. These anomalous vectors are interpreted to be the result of tectonic rotation about vertical axes rather than to reflect anomalous magnetic field orientations associated with a polarity transition. Although these sample sites are within igneous intrusive bodies with no control on the original attitude during acquisition of the natural remanent magnetization, the relative conformity of data from numerous separate intrusions requires an average 90° megatectonic rotation of both the Villa de Cura and Tinaco tectonic belts of the Caribbean Mountains. On the other hand, seven sites from the Paraguana Peninsula (and two sites from the younger Tertiary Falcon basin) have southerly declination and positive inclination. These vectors can be explained by rotation about horizontal east-west axes during Cenozoic folding. A compilation of available paleomagnetic data from rocks of Cretaceous age in the Caribbean indicates that anomalous declinations are widespread in both the Greater Antilles and Caribbean Mountains. We interpret these data to support previous suggestions of megatectonic rotations of a more linear, north-south trending Mesozoic island arc system that included portions of the Greater Antilles and Caribbean Mountains of Venezuela.

  9. The significance of tectonism in the glaciations of Greece

    NASA Astrophysics Data System (ADS)

    Bathrellos, George; Skilodimou, Hariklia; Maroukian, Habik

    2014-05-01

    In Greece, Middle to Late Pleistocene mountain glaciations appear to have been quite extensive, along the mountain range of Pindus, on Mt. Olympus and in the highlands of Peloponnesus. This study focuses on the Middle to Late Pleistocene glaciations based on the examination of cirque formations and their elevation changes due to vertical tectonism, in certain parts of Greece, namely Pindus, Mt. Olympus and Peloponnesus. An initial spatial database of these glacial forms was created including their location and mean elevation. Some of the glaciated sites have been taken from previous literature and others were recorded from topographic maps, air photos and field work. ArcGIS 10 software was used to process the glaciated sites. A map depicting the glaciated areas of Greek regions was compiled with over 230 cirques. A cirque's top, lip and margins of each location were mapped. So altitudes of apex and lip and mean altitude of each cirque ([apex+lip]/2), were calculated. A total number of 239 inactive cirques was recorded with limestone as the dominant lithology. As one moves to the south, in the case of Pindus range and its extension in the Peloponnesus, the number of cirques decreases. These glacial forms occur at altitudes varying from 2,770 to 1,600 m.a.s.l. Thus the preservation of ice for longer periods of time is more likely at altitudes higher than 1,600 m.a.s.l. Concerning the distribution of the mean elevations of cirques one should take into consideration the tectonic activity of the study area. Especially in the Pindus range, Mount Olympus, and Peloponnesus this process is in the form of uplift. This has increased the mean elevation of the cirques in every following ice age. So, in older times many cirques were a few hundred meters lower than the more recent glacial period.

  10. Devonian brachiopods of southwesternmost laurentia: Biogeographic affinities and tectonic significance

    USGS Publications Warehouse

    Boucot, A.J.; Poole, F.G.; Amaya-Martinez, R.; Harris, A.G.; Sandberg, C.A.; Page, W.R.

    2008-01-01

    Three brachiopod faunas discussed herein record different depositional and tectonic settings along the southwestern margin of Laurentia (North America) during Devonian time. Depositional settings include inner continental shelf (Cerros de Los Murcielagos), medial continental shelf (Rancho Placeritos), and offshelf continental rise (Rancho Los Chinos). Ages of Devonian brachiopod faunas include middle Early (Pragian) at Rancho Placeritos in west-central Sonora, late Middle (Givetian) at Cerros de Los Murcielagos in northwestern Sonora, and late Late (Famennian) at Rancho Los Chinos in central Sonora. The brachiopods of these three faunas, as well as the gastropod Orecopia, are easily recognized in outcrop and thus are useful for local and regional correlations. Pragian brachiopods dominated by Acrospirifer and Meristella in the "San Miguel Formation" at Rancho Placeritos represent the widespread Appohimchi Subprovince of eastern and southern Laurentia. Conodonts of the early to middle Pragian sulcatus to kindlei Zones associated with the brachiopods confirm the ages indicated by the brachiopod fauna and provide additional information on the depositional setting of the Devonian strata. Biostratigraphic distribution of the Appohimchi brachiopod fauna indicates continuous Early Devonian shelf deposition along the entire southern margin of Laurentia. The largely emergent southwest-trending Transcontinental arch apparently formed a barrier preventing migration and mixing of many genera and species of brachiopods from the southern shelf of Laurentia in northern Mexico to the western shelf (Cordilleran mio-geocline) in the western United States. Middle Devonian Stringocephalus brachiopods and Late Devonian Orecopia gastropods in the "Los Murcielagos Formation" in northwest Sonora represent the southwest-ernmost occurrence of these genera in North America and date the host rocks as Givetian and Frasnian, respectively. Rhynchonelloid brachiopods (Dzieduszyckia sonora) and

  11. Tectonic significance of serpentinite from ocean to subduction (Invited)

    NASA Astrophysics Data System (ADS)

    Guillot, S.

    2013-12-01

    At plate boundaries, where deformation is localized along centimeter- to kilometer-scale shear zones, the influence of serpentinite on tectonic processes is linked to its unique rheological properties. Geophysical profiles at the Ocean-Continent Transition (OCT) indicate that the serpentinized mantle is about 5 km thick. Serpentinization weakens the upper mantle layer, promoting strain localization and allowing the normal faults in the distal margin of the OCT to root at low angle. The ongoing extension leads to buoyant flow of partially serpentinized mantle along low-angle detachment faults, leading to the horizontal stretching of the subcontinental mantle at the seafloor. At slow spreading ridges, 20 to 25% of the seafloor is composed of serpentinite associated with domal structures. Extensional deformation is localized in a ~100 to 200 m thick shear zone at the footwall of the detachment zone. Within the detachment fault, the mineralogy is complex; including talc, amphibole, and chorite indicating the addition of silica, calcium, and aluminum to serpentinites from hydrothermal fluids. Large-scale continental strike-slip faults can either slip by aseismic creep or move abruptly during earthquakes. Weak fault behavior can be caused by high fluid pressures, locally high geothermal gradients, or the presence of weak materials such as serpentinite. Along The San Andreas Fault (SAF), serpentinites have been associated with fault creep, as well as low fault strength. The SAFOD project (San Andreas Fault Observatory at Depth) intersects the Great Valley Formation at 3 km depth. Microstructural observations from core samples show evidence of deformation across the damaged zone. The deforming zones contain serpentinite clasts, talc and highly sheared siltstones dispersed in a matrix of saponite (Mg-rich smectite clay), which is one of the weakest phyllosilicates. Within subduction zone, decoupling between the mantle wedge and the subducting slab is inferred from modeling

  12. Characteristics of the Cenozoic crustal deformations in SE Korea and its vicinity due to major tectonic events

    NASA Astrophysics Data System (ADS)

    Son, M.; Kim, J.; Song, C.; Sohn, Y.; Kim, I.

    2010-12-01

    The southeastern Korean Peninsula has experienced multiple crustal deformations according to changes of global tectonic setting during the Cenozoic. Characteristics of the crustal deformations in relation to major Cenozoic tectonic events are summarized as follows. (1) Collision of Indian and Eurasian continents and abrupt change of movement direction of the Pacific plate (50 ~ 43 Ma): The collision of Indian and Eurasian continents caused the eastward extrusion of East Asia block as a trench-rollback, and then the movement direction of the Pacific plate was abruptly changed from NNW to WNW. As a result, the strong suction-force along the plate boundary produced a tensional stress field trending EW or WNW-ESE in southeastern Korea, which resultantly induced the passive intrusion of NS or NNE trending mafic dike swarm pervasively. (2) Opening of the East Sea (25 ~ 16 Ma): The NS or NNW-SSE trending opening of the East Sea generated a dextral shear stress regime trending NNW-SSE along the eastern coast line of the Korean Peninsula. As a result, pull-apart basins were developed in right bending and overstepping parts along major dextral strike slip faults trending NNW-SSE in southeastern Korea. The basins can be divided into two types on the basis of geometry and kinematics: Parallelogram-shaped basin (rhombochasm) and wedged-shaped basin (sphenochasm), respectively. At that time, the basins and adjacent basement blocks experienced clockwise rotation and northwestward tilting, and the eastward propagating rifting also occurred. At about 17 Ma, the Yeonil Tectonic Line, which is the westernmost border fault of the Miocene crustal deformation in southeastern Korea, began to move as a major dextral strike slip fault. (3) Clockwise rotation of southeastern Japan Island (16~15 Ma): The collision of the Izu-Bonin Arc and southeastern Japan Island, as a result of northward movement of the Philippine sea-plate, induced the clockwise rotation of southeastern Japan Islands. The

  13. Tectonics

    NASA Astrophysics Data System (ADS)

    John Dewey will complete his term as editor-in-chief of Tectonics at the end of 1984. Clark Burchfiel's term as North American Editor will also end. Tectonics is published jointly with the European Geophysical Society. This newest of AGU's journals has already established itself as an important journal bridging the concerns of geophysics and geology.James A. Van Allen, president of AGU, has appointed a committee to recommend candidates for both editor-in-chief and North American editor for the 1985-1987 term.

  14. Shallow hydraulic fracturing measurements in Korea support tectonic and seismic indicators of regional stress.

    SciTech Connect

    Haimson, Bezalel Cecil; Lee, Moo Yul; Song, I.

    2003-07-01

    We have conducted five hydraulic fracturing stress measurement campaigns in Korea, involving 13 test holes ranging in depth from 30 to 250 m, at locations from North Seoul to the southern coast of the peninsula. The measurements reveal consistent crustal stress magnitudes and directions that suggest persistence throughout western and southern Korea. The maximum horizontal stress {sigma}{sub H} is oriented between ENE-WSW and E-W, in accord with plate movement and deformation, and with directions indicated by both focal mechanism solutions from earthquakes inland and offshore as well as borehole breakouts in mainland China close to its eastern coast. With respect to magnitudes, the vertical stress is the overall minimum stress at all tested locations, suggesting a thrust faulting regime within the relatively shallow depths reached by our tests. Typically, such a stress regime becomes one favoring strike-slip at greater depths, as is also indicated by the focal mechanism solutions around Korea.

  15. Ancient wells and their geoarchaeological significance in detecting tectonics of the Israel Mediterranean coastline region

    NASA Astrophysics Data System (ADS)

    Nir, Yaacov; Eldar, Iris

    1987-01-01

    Eight ancient water wells, representing the late Bronze Age to the Crusades period (ca. 3100 700 B.P.), have recently been excavated (six by the authors) and reopened at archaeological sites (tels) along the southern and central Mediterranean coast of Israel. Evidence of ancient freshwater levels directly reflects on possible neotectonics of the region and on eustatic changes of sea level. There is substantial disagreement about the tectonic stability of the Israel Mediterranean coastal region during the past 3500 yr, whether there was a large-magnitude tectonic event (one of the largest known for recent times) during the period in discussion or whether the region was tectonically quiet. We tested the instability hypothesis by using geoarchaeological data from the wells and found no evidence for significant tectonic deformation of the central and southern Israel coast in the past 3100 yr. The “ancient water-well” method can, with appropriate modifications, be used all around the Mediterranean and other coasts elsewhere in the world where ground-water-sea-level relations are alike. Now in the digging of wells we must not disdain reflection, but must devote much acuteness and skill to the consideration of the natural principles of things. Vitruvius Pollio, Architectura, Book VIII, Chapter VI (25 B.C.)

  16. Paleomagnetism and U-Pb geochronology of the late Cretaceous Chisulryoung Volcanic Formation, Korea: tectonic evolution of the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Jeong, Doohee; Yu, Yongjae; Doh, Seong-Jae; Suk, Dongwoo; Kim, Jeongmin

    2015-05-01

    Late Cretaceous Chisulryoung Volcanic Formation (CVF) in southeastern Korea contains four ash-flow ignimbrite units (A1, A2, A3, and A4) and three intervening volcano-sedimentary layers (S1, S2, and S3). Reliable U-Pb ages obtained for zircons from the base and top of the CVF were 72.8 ± 1.7 Ma and 67.7 ± 2.1 Ma, respectively. Paleomagnetic analysis on pyroclastic units yielded mean magnetic directions and virtual geomagnetic poles (VGPs) as D/ I = 19.1°/49.2° ( α 95 = 4.2°, k = 76.5) and VGP = 73.1°N/232.1°E ( A 95 = 3.7°, N = 3) for A1, D/ I = 24.9°/52.9° ( α 95 = 5.9°, k = 61.7) and VGP = 69.4°N/217.3°E ( A 95 = 5.6°, N = 11) for A3, and D/ I = 10.9°/50.1° ( α 95 = 5.6°, k = 38.6) and VGP = 79.8°N/242.4°E ( A 95 = 5.0°, N = 18) for A4. Our best estimates of the paleopoles for A1, A3, and A4 are in remarkable agreement with the reference apparent polar wander path of China in late Cretaceous to early Paleogene, confirming that Korea has been rigidly attached to China (by implication to Eurasia) at least since the Cretaceous. The compiled paleomagnetic data of the Korean Peninsula suggest that the mode of clockwise rotations weakened since the mid-Jurassic. Such interesting variation of vertical rotations in the Korean Peninsula might result from the strike-slip motions of major faults developed in East Asia (the Tancheng-Lujiang fault to the northwest and the Korea-Taiwan strait fault to the southeast), near-field tectonic forcing of the subducting Pacific Plate beneath the Eurasian Plate, and far-field expressions of the India-Asia collision.

  17. Fault zone evolution in a Cenozoic inversion tectonic setting, SE Korea

    NASA Astrophysics Data System (ADS)

    Kim, Young-Seog; Lee, Minjoo; Han, Seung-Rok

    2010-05-01

    The Korean peninsula has been considered as a tectonically safe region from earthquakes, because it is located in a stable margin of the Eurasian plate. However, more than 30 Quaternary faults have recently been reported from the southeastern part of the Korean peninsula. The studied fault zone is an N-S trending fault located in the northern extent of the Quaternary Eupcheon Fault, which composed of several fault gouges indicating multiple deformations. The fault zone (fault core) is exposed over 1 km long and the thickness is up to 2m. The fault gouge zone is composed of several different colored gouge bands. Well-exposed vertical and horizontal sections are analyzed so as to understand the characteristics of the fault and fault zone evolution. The analyzed kinematic indicators such as cleavages, lineations and slickenlines suggest that the fault underwent early normal slip under SE extension and was later reactivated under NNW compression resulting in inversion tectonics. Major fault zones do not cross-cut each other; instead, the fault gouges within the fault zone split and merge into other fault zones. Fault rocks developed in this fault zone show asymmetrical features including lens-shaped breccias blocks in gouge zones, and asymmetric distributions of grain size and fracture density, indicating mature fault system and asymmetric fault zone evolution. The hanging wall block of the fault shows relatively highly damaged fracture patterns indicating that the hanging wall is weaker than footwall. Therefore, detailed analysis of fault and fracture patterns, and characteristics of fault zones must be very useful in evaluation of fault zone evolution and characteristics of foundation.

  18. Source process and tectonic implication of the January 20, 2007 Odaesan earthquake, South Korea

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, Ali K.; Kim, K. Y.; Fnais, M. S.; Al-Amri, A. M.

    2014-04-01

    The source process for the 20th of January 2007, Mw 4.5 Odaesan earthquake in South Korea is investigated in the low- and high-frequency bands, using velocity and acceleration waveform data recorded by the Korea Meteorological Administration Seismographic Network at distances less than 70 km from the epicenter. Synthetic Green functions are adopted for the low-frequency band of 0.1-0.3 Hz by using the wave-number integration technique and the one dimensional velocity model beneath the epicentral area. An iterative technique was performed by a grid search across the strike, dip, rake, and focal depth of rupture nucleation parameters to find the best-fit double-couple mechanism. To resolve the nodal plane ambiguity, the spatiotemporal slip distribution on the fault surface was recovered using a non-negative least-square algorithm for each set of the grid-searched parameters. The focal depth of 10 km was determined through the grid search for depths in the range of 6-14 km. The best-fit double-couple mechanism obtained from the finite-source model indicates a vertical strike-slip faulting mechanism. The NW faulting plane gives comparatively smaller root-mean-squares (RMS) error than its auxiliary plane. Slip pattern event provides simple source process due to the effect of Low-frequency that acted as a point source model. Three empirical Green functions are adopted to investigate the source process in the high-frequency band. A set of slip models was recovered on both nodal planes of the focal mechanism with various rupture velocities in the range of 2.0-4.0 km/s. Although there is a small difference between the RMS errors produced by the two orthogonal nodal planes, the SW dipping plane gives a smaller RMS error than its auxiliary plane. The slip distribution is relatively assessable by the oblique pattern recovered around the hypocenter in the high-frequency analysis; indicating a complex rupture scenario for such moderate-sized earthquake, similar to those reported

  19. Volcanic activity before and after large tectonic earthquakes: Observations and statistical significance

    NASA Astrophysics Data System (ADS)

    Eggert, Silke; Walter, Thomas R.

    2009-06-01

    The study of volcanic triggering and interaction with the tectonic surroundings has received special attention in recent years, using both direct field observations and historical descriptions of eruptions and earthquake activity. Repeated reports of clustered eruptions and earthquakes may imply that interaction is important in some subregions. However, the subregions likely to suffer such clusters have not been systematically identified, and the processes responsible for the observed interaction remain unclear. We first review previous works about the clustered occurrence of eruptions and earthquakes, and describe selected events. We further elaborate available databases and confirm a statistically significant relationship between volcanic eruptions and earthquakes on the global scale. Moreover, our study implies that closed volcanic systems in particular tend to be activated in association with a tectonic earthquake trigger. We then perform a statistical study at the subregional level, showing that certain subregions are especially predisposed to concurrent eruption-earthquake sequences, whereas such clustering is statistically less significant in other subregions. Based on this study, we argue that individual and selected observations may bias the perceptible weight of coupling. The activity at volcanoes located in the predisposed subregions (e.g., Japan, Indonesia, Melanesia), however, often unexpectedly changes in association with either an imminent or a past earthquake.

  20. Backarc mafic-ultramafic magmatism in Northeastern Vietnam and its regional tectonic significance

    NASA Astrophysics Data System (ADS)

    Thanh, Ngo Xuan; Hai, Tran Thanh; Hoang, Nguyen; Lan, Vu Quang; Kwon, Sanghoon; Itaya, Tetsumaru; Santosh, M.

    2014-08-01

    The geology of Northern Vietnam offers critical clues on the convergence history between the South China and Indochina blocks. We constrain the tectonic evolution of the South China and Indochina blocks using geochemical, mineral chemical and geochronological data collected from mafic-ultramafic rocks exposed in the Cao Bang area, Northeastern Vietnam. These rocks show significant enrichment in large ionic lithophile elements (LILEs) such as Cs, Rb, Ba, Th, U, and Pb and depletion in high field strength elements (HFSEs) such as Nb, Ta, Zr, and Ti showing [Nb/La]N between 0.28-0.41, [La/Yb]N = 3.94-10.00 and Zr/Y = 2.0-4.4. These geochemical features as well as the petrology and mineral chemistry of the Cao Bang mafic-ultramafic magmas are comparable to those of magmatic complexes formed in a back-arc environment. The basalts yield Rb-Sr whole rock ages of 263 ± 15 Ma, that are consistent with the zircon U-Pb and K-Ar ages reported in previous studies from the same area. The spatial and temporal distribution of the arc magmas within the Indochina block and along the southern margin of the South China block suggest that the Permo-Triassic mafic-ultramafic magmas formed during a tectonic event that is different from the subduction and collision event between the Indochina and South China blocks.

  1. Structural analysis and evolution of the Hadong-Sancheong-Hwagae area in the Yeongnam massif, Korea: a NS-trend tectonic frame in the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Deok-Seon, Lee; Ji-Hoon, Kang

    2016-04-01

    The Hadong-Sancheong-Hwagae area in the Jirisan province of the Yeongnam massif, Korea, is mainly composed of Precambrian Hadong anorthosite complex (HAC), Precambrian Jirisan metamorphic rock complex (JMRC), Jurassic˜Triassic granitoids which intrude them, and Cretaceous sedimentary rocks which unconformably cover them. Lithofacies distribution and tectonic frame of the Precambrian constituent rocks mainly show a NS trend, unlike a general NE trend of those in the Korean Peninsula. To unravel the geological structures associated with the NS-trend tectonic frame which was built in the HAC and JMRC, we researched the structural characteristics of each deformation phase based on the geometric and kinematic features and the forming sequence of rock structures of the multi-deformed HAC and JMRC. The results indicate that the pre-Late Paleozoic geological structures of this area were formed at least through the following three times of ductile deformation phases. The D1 deformation happened due to the large-scale top-to-the SE shearing, and formed sheath or A-type folds and a regional NE trend of tectonic frame in the HAC and JMRC. The D2 deformation occurred under the EW-directed tectonic compression, and formed a regional NS trend of active and passive folds and Hadong ductile shear zone over 2.3˜1.4 km width, and transposed most of D1 tectonic frame into D1-2 composite tectonic frame. The extensive Hadong shear zone, which was formed in the mylonitization process accompanying the passive folding, was persistently developed along the eastern boundary of HAC and JMRC which corresponds to a limb of passive fold on a geological map scale. It produced a very strong mylonitic structure and stretching lineation. The NE-trend D1 structural elements were mainly reoriented into NS trend by the powerful active and passive folding. The D3 deformation occurred under the NS-trend tectonic compression environment, and formed EW-trend kink or open folds, and partially rearranged

  2. The geology and tectonic significance of the Big Creek Gneiss, Sierra Madre, southeastern Wyoming

    NASA Astrophysics Data System (ADS)

    Jones, Daniel S.

    The Big Creek Gneiss, southern Sierra Madre, southeastern Wyoming, is a heterogeneous suite of upper-amphibolite-facies metamorphic rocks intruded by post-metamorphic pegmatitic granite. The metamorphic rocks consist of three individual protolith suites: (1) pre- to syn-1780-Ma supracrustal rocks including clastic metasedimentary rocks, calc-silicate paragneiss, and metavolcanic rocks; (2) a bimodal intrusive suite composed of metagabbro and granodiorite-tonalite gneiss; and (3) a younger bimodal suite composed of garnet-bearing metagabbronorite and coarse-grained granitic gneiss. Zircons U-Pb ages from the Big Creek Gneiss demonstrate that: (1) the average age of detrital zircons in the supracrustal rocks is ~1805 Ma, requiring a significant source of 1805-Ma (or older) detritus during deposition, possibly representing an older phase of arc magmatism; (2) the older bimodal igneous suite crystallized at ~1780 Ma, correlative with arc-derived rocks of the Green Mountain Formation; (3) the younger bimodal igneous suite crystallized at ~1763 Ma, coeval with the extensional(?) Horse Creek anorthosite complex in the Laramie Mountains and Sierra Madre Granite batholith in the southwestern Sierra Madre; (4) Big Creek Gneiss rocks were tectonically buried, metamorphosed, and partially melted at ~1750 Ma, coeval with the accretion of the Green Mountain arc to the Wyoming province along the Cheyenne belt; (5) the posttectonic granite and pegmatite bodies throughout the Big Creek Gneiss crystallized at ~1630 Ma and are correlative with the 'white quartz monzonite' of the south-central Sierra Madre. Geochemical analysis of the ~1780-Ma bimodal plutonic suite demonstrates a clear arc-affinity for the mafic rocks, consistent with a subduction environment origin. The granodioritic rocks of this suite were not derived by fractional crystallization from coeval mafic magmas, but are instead interpreted as melts of lower-crustal mafic material. This combination of mantle

  3. Convergence of tectonic reconstructions and mantle convection models for significant fluctuations in seafloor spreading

    NASA Astrophysics Data System (ADS)

    Coltice, N.; Seton, M.; Rolf, T.; Müller, R. D.; Tackley, P. J.

    2013-12-01

    For 50 years of data collection and kinematic reconstruction efforts, plate models have provided alternative scenarios for plate motions and seafloor spreading for the past 200 My. However, these efforts are naturally limited by the incomplete preservation of very old seafloor, and therefore the time-dependence of the production of new seafloor is controversial. There is no consensus on how much it has varied in the past 200 My, and how it could have fluctuated over longer timescales. We explore how seafloor spreading and continental drift evolve over long geological periods using independently derived models: a recently developed geodynamic modelling approach and state-of-the-art plate reconstructions. Both kinematic reconstructions and geodynamic models converge on variations by a factor of 2 in the rate of production of new seafloor over a Wilson cycle, with concomitant changes of the shape of the area-age distribution of the seafloor between end members of rectangular, triangular and skewed distributions. Convection models show that significant fluctuations over longer periods (∼1 Gy) should exist, involving changes in ridge length and global tectonic reorganisations. Although independent, both convection models and kinematic reconstructions suggest that changes in ridge length are at least as significant as spreading rate fluctuations in driving changes in the seafloor area-age distribution through time.

  4. Significant Centers of Tectonic Activity as Identified by Wrinkle Ridges for the Western Hemisphere of Mars

    NASA Technical Reports Server (NTRS)

    Anderson, R.C.; Haldemann, A. F. C.; Golombek, M. P.; Franklin, B. J.; Dohm, J. M.; Lias, J.

    2000-01-01

    The western hemisphere region of Mars has been the site of numerous scientific investigations regarding its tectonic evolution. For this region of Mars, the dominant tectonic region is the Tharsis province. Tharsis is characterized by an enormous system of radiating grabens and a circumferential system of wrinkle ridges. Past investigations of grabens associated with Tharsis have identified specific centers of tectonic activity. A recent structural analysis of the western hemisphere region of Mars which includes the Tharsis region, utilized 25,000 structures to determine the history of local and regional centers of tectonic activity based primarily on the spatial and temporal relationships of extensional features. This investigation revealed that Tharsis is more structurally complex (heterogeneous) than has been previously identified: it consists of numerous regional and local centers of tectonic activity (some are more dominant and/or more long lived than others). Here we use the same approach as Anderson et al. to determine whether the centers of tectonic activity that formed the extensional features also contributed to wrinkle ridge (compressional) formation.

  5. An extraordinary palaeontinid from the Triassic of Korea and its significance

    PubMed Central

    Nam, Kye Soo; Wang, Ying; Ren, Dong; Kim, Jong Heon; Szwedo, Jacek

    2017-01-01

    A new, extraordinary palaeontinid Hallakkungis amisanus Nam, Wang & Szwedo, gen. et sp. nov., from the Upper Triassic of the Amisan Formation in Boryeong City, Korea is described. It is the first Palaeontinidae from Korea. The newly described taxon displays a mosaic of characters present in presumed ancestors of this insect family and some highly advanced features. PMID:28098190

  6. An extraordinary palaeontinid from the Triassic of Korea and its significance

    NASA Astrophysics Data System (ADS)

    Nam, Kye Soo; Wang, Ying; Ren, Dong; Kim, Jong Heon; Szwedo, Jacek

    2017-01-01

    A new, extraordinary palaeontinid Hallakkungis amisanus Nam, Wang & Szwedo, gen. et sp. nov., from the Upper Triassic of the Amisan Formation in Boryeong City, Korea is described. It is the first Palaeontinidae from Korea. The newly described taxon displays a mosaic of characters present in presumed ancestors of this insect family and some highly advanced features.

  7. An extraordinary palaeontinid from the Triassic of Korea and its significance.

    PubMed

    Nam, Kye Soo; Wang, Ying; Ren, Dong; Kim, Jong Heon; Szwedo, Jacek

    2017-01-18

    A new, extraordinary palaeontinid Hallakkungis amisanus Nam, Wang &Szwedo, gen. et sp. nov., from the Upper Triassic of the Amisan Formation in Boryeong City, Korea is described. It is the first Palaeontinidae from Korea. The newly described taxon displays a mosaic of characters present in presumed ancestors of this insect family and some highly advanced features.

  8. Tectonic ironstones in the Zimbabwe craton and their significance for greenstone belt geology

    NASA Astrophysics Data System (ADS)

    Hofmann, A.; Dirks, P.; Jelsma, H.; Matura, N.

    2003-04-01

    The tectonic interpretation of Archaean greenstone belts hinges on the correct recognition, interpretation and correlation of unconformities, stratigraphic marker horizons and layer-parallel shear zones. Metre-thick horizons of ironstone lithologically similar to "sulfide-facies" banded iron formation are a common component of the greenstone stratigraphy of the late Archaean Zimbabwe craton. These rocks are commonly associated with proposed unconformities and have been used extensively as stratigraphic markers in the past. However, they show features which are not compatible with a sedimentary origin and are herein interpreted as silicified and sulfide-impregnated shear zones. Such tectonic ironstones separate different lithostratigraphic units commonly regarded as autochthonous rock sequences. On outcrop scale, shearing along ironstone horizons is indicated by anastomosing foliation domains, folding, boudinage and mylonitic fabrics, and, on a regional scale, by truncation of bedding and/or foliation, an anastomosing geometry of the horizons and duplication/juxtaposition of lithostratigraphic units. Tectonic ironstone formation is attributed to in situ silicification and iron (sulfide)-impregnation of rocks, commonly sediments, by mineralized fluids that penetrated the shear zones and their immediate wall rocks. Shear zones containing tectonic ironstone frequently represent detachment surfaces at the base of now juxtaposed lithotectonic units. These tectonic contacts can resemble angular unconformities where footwall cut-offs occur. The shear zones formed as a result of thin-skinned thrust tectonics that gave rise to horizontal accretion, imbrication and juxtaposition of volcanic and sedimentary rock units prior to deformation associated with granitoid diapirism. As a result, "layer-cake" stratigraphic models of greenstone sequences containing tectonic ironstone "layers" have to be treated with care. We also want to encourage caution when using cherts or ironstones

  9. Emergence of the significant local warming of Korea in CMIP5 projections

    NASA Astrophysics Data System (ADS)

    Boo, Kyung-On; Shim, Sungbo; Kim, Jee-Eun

    2016-04-01

    According to IPCC AR5, anthropogenic influence on warming is obvious in local scales, especially in some tropical regions. Detection of significant local warming is important for adaptation to climate change of society and ecosystem. Recently much attention has focused on the time of emergence (ToE) for the signal of anthropogenic climate change against the natural climate variability. Motivated from the previous studies, this study analyzes ToE of regional surface air temperature over Korea. Simulations of CMIP5 15 models are used for RCP 2.6, 4.5 and 8.5. For each year, JJA and DJF temperature anomalies are calculated for the time period 1900-1929. For noise of interannual variability, natural-only historical simulations of CMIP5 12 models are used and the standard deviation of the time series is obtained. For signal of warming, we examine the year when the signal above 2 standard deviations is detected in 80% of the models using 30-year smoothed time series. According to our results, interannual variability is larger in land than ocean. Seasonally, it is larger in winter than in summer. Accordingly, ToE of summertime temperature is earlier than that in winter and is expected to appear in 2030s from three RCPs. The seasonal difference is consistent with previous studies. Wintertime ToE appears in 2040s for RCP85 and 2060s for RCP4.5. The different emergence time between RCP8.5 and RCP4.5 reflects the influence of mitigation. In a similar way, daily maximum and minimum temperatures are analyzed. ToE of Tmin appears earlier than that of Tmax and difference is small. Acknowledgements. This study is supported by the National Institute of Meteorological Sciences, Korea Meteorological Administration (NIMR-2012-B-2).

  10. Paleoseismological research on Langshan Range Front Fault and its tectonics significance

    NASA Astrophysics Data System (ADS)

    Dong, S.; Zhang, P.; Yu, Z.; Lei, Q.

    2012-12-01

    The ~400-km-long, ~90-km-wide Ordos Block, the very famous loess plateau in China, east to Luliang Ranges, west to Zhuozi Shan, Yunwu Shan, south to Weibei hill area, north to the side of Yellow River,is the most stable and completed sub tectonic element in Sino-Korean Platform. Since Ordos Block locates between world-famous collision-related extrusion tectonics in Tibet and subduction-induced back-arc tectonics along the western Pacific, now it's still being effected by these two tectonics zones. The present and Cenozoic activity of Ordos Block and the peripheral tectonic zones plays the key role in understanding the dynamics mechanism, evolution process of, and the effect between these two tectonics zones of Cenozoic age and now. The ~160-km-long Lang Shan Range Front Fault in the northwest corner of the Hetao Basin is a very important basin-controlling striking NNE active fault, and plays key role in understanding the dynamics mechanism and earthquake risk of Hetao Basin, which is northern boundary zone of Ordos Block. We excavated several trenches across the fault, in which three trenches, Dongshen Village Trench, Qingshanbei Trench, and Wulanhushao Trench, we distinguished three, two and three paleoevents respectively, according to OSL and charcoal dating samples. We also obtain the fault slip rate combining detail topographic survey at the trenches' area and previous researchers' study. Based on field scratch on fault plane and the latest geomorphological evidence, almost no lateral slip amount was discovered, which is different from current viewpoint on the fault with left lateral slip amount. This is very helpful to analyse geodynamical balance of Hetao Basin in such complicated geodynamical environment. This paper displays how the geodynamic system works now combining previous scientists' conclusion.

  11. Relocation of earthquakes at southwestern Indian Ocean Ridge and its tectonic significance

    NASA Astrophysics Data System (ADS)

    Luo, W.; Zhao, M.; Haridhi, H.; Lee, C. S.; Qiu, X.; Zhang, J.

    2015-12-01

    The southwest Indian Ridge (SWIR) is a typical ultra-slow spreading ridge (Dick et al., 2003) and further plate boundary where the earthquakes often occurred. Due to the lack of the seismic stations in SWIR, positioning of earthquakes and micro-earthquakes is not accurate. The Ocean Bottom Seismometers (OBS) seismic experiment was carried out for the first time in the SWIR 49 ° 39 'E from Jan. to March, 2010 (Zhao et al., 2013). These deployed OBS also recorded the earthquakes' waveforms during the experiment. Two earthquakes occurred respectively in Feb. 7 and Feb. 9, 2010 with the same magnitude of 4.4 mb. These two earthquakes were relocated using the software HYPOSAT based on the spectrum analysis and band-pass (3-5 Hz) filtering and picking up the travel-times of Pn and Sn. Results of hypocentral determinations show that there location error is decreased significantly by joined OBS's recording data. This study do not only provide the experiences for the next step deploying long-term wide-band OBSs, but also deepen understanding of the structure of SWIR and clarify the nature of plate tectonic motivation. This research was granted by the Natural Science Foundation of China (41176053, 91028002, 91428204). Keywords: southwest Indian Ridge (SWIR), relocation of earthquakes, Ocean Bottom Seismometers (OBS), HYPOSAT References:[1] Dick, H. J. B., Lin J., Schouten H. 2003. An ultraslow-spreading class of ocean ridge. Nature, 426(6965): 405-412. [2] Zhao M. H., et al. 2013. Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49°39' E). Geochemistry Geophysics Geosystems, 14(10): 4544-4563.

  12. Post-depositional tectonic modification of VMS deposits in Iberia and its economic significance

    NASA Astrophysics Data System (ADS)

    Castroviejo, Ricardo; Quesada, Cecilio; Soler, Miguel

    2011-07-01

    The original stratigraphic relationships and structure of VMS deposits are commonly obscured by deformation. This can also affect their economic significance, as shown by several Iberian Pyrite Belt (IPB, SW Iberia) examples. The contrasting rheologic properties of the different lithologies present in an orebody (massive sulphide, feeder stockwork, alteration envelope, volcanic and sedimentary rocks) play a major role in determining its overall behaviour. Variscan thin-skinned tectonics led to stacking of the massive pyrite and stockwork bodies in duplex structures, resulting in local thickening and increased tonnage of minable mineralization. Furthermore, differential mechanical behaviour of the different sulphide minerals localised the detachments along relatively ductile sulphide-rich bands. The result was a geochemical and mineralogical reorganisation of most deposits, which now consist of barren, massive pyrite horses, bounded by base metal-rich ductile shear zones. Metal redistribution was enhanced by mobilisation of the base metal sulphides from the initially impoverished massive pyrite, through pressure-solution processes, to tensional fissures within the already ductile shear zones. In NW Iberia, VMS deposits were also strongly overprinted by the Variscan deformation during emplacement of the Cabo Ortegal and Órdenes allochthonous nappe complexes, but no stacking of the orebodies was produced. Original contacts were transposed, and the orebodies, their feeder zones and the country rock acquired pronounced laminar geometry. In lower-grade rocks (greenschist facies, Cabo Ortegal Complex), solution transfer mechanisms are common in pyrite, which remains in the brittle domain, while chalcopyrite shows ductile behaviour. In higher-grade rocks (amphibolite facies, Órdenes Complex), metamorphic recrystallisation overprints earlier deformation textures. The contrasting behaviour of the IPB and NW Iberian deposits is explained by key factors that affect their

  13. Volcanic activity before and after large tectonic earthquakes: Observations and statistical significance

    NASA Astrophysics Data System (ADS)

    Eggert, S.; Walter, T. R.

    2009-04-01

    The study of volcanic triggering and coupling to the tectonic surroundings has received special attention in recent years, using both direct field observations and historical descriptions of eruptions and earthquake activity. Repeated reports of volcano-earthquake interactions in, e.g., Europe and Japan, may imply that clustered occurrence is important in some regions. However, the regions likely to suffer clustered eruption-earthquake activity have not been systematically identified, and the processes responsible for the observed interaction are debated. We first review previous works about the correlation of volcanic eruptions and earthquakes, and describe selected local clustered events. Following an overview of previous statistical studies, we further elaborate the databases of correlated eruptions and earthquakes from a global perspective. Since we can confirm a relationship between volcanic eruptions and earthquakes on the global scale, we then perform a statistical study on the regional level, showing that time and distance between events follow a linear relationship. In the time before an earthquake, a period of volcanic silence often occurs, whereas in the time after, an increase in volcanic activity is evident. Our statistical tests imply that certain regions are especially predisposed to concurrent eruption-earthquake pairs, e.g., Japan, whereas such pairing is statistically less significant in other regions, such as Europe. Based on this study, we argue that individual and selected observations may bias the perceptible weight of coupling. Volcanoes located in the predisposed regions (e.g., Japan, Indonesia, Melanesia), however, indeed often have unexpectedly changed in association with either an imminent or a past earthquake.

  14. International Tectonic Map of the Circumpolar Arctic and its Significance for Geodynamic Interpretations

    NASA Astrophysics Data System (ADS)

    Petrov, O. V.; Morozov, A.; Shokalsky, S.; Leonov, Y.; Grikurov, G.; Poselov, V.; Pospelov, I.; Kashubin, S.

    2011-12-01

    In 2003 geological surveys of circum-arctic states initiated the international project "Atlas of Geological Maps of Circumpolar Arctic at 1:5 000000 scale". The project received active support of the UNESCO Commission for the Geological Map of the World (CGMW) and engaged a number of scientists from national academies of sciences and universities. Magnetic and gravity maps were prepared and printed by the Norwegian Geological Survey, and geological map was produced by the Geological Survey of Canada. Completion of these maps made possible compilation of a new Tectonic Map of the Arctic (TeMAr), and this work is now in progress with Russian Geological Research Institute (VSEGEI) in the lead of joint international activities. The map area (north of 60o N) includes three distinct roughly concentric zones. The outer onshore rim is composed of predominantly mature continental crust whose structure and history are illustrated on the map by the age of consolidation of craton basements and orogenic belts. The zone of offshore shelf basins is unique in dimensions with respect to other continental margins of the world. Its deep structure can in most cases be positively related to thinning and rifting of consolidated crust, sometimes to the extent of disruption of its upper layer, whereas the pre-rift evolution can be inferred from geophysical data and extrapolation of geological evidence from the mainland and island archipelagoes. The central Arctic core is occupied by abyssal deeps and intervening bathymetric highs. The Eurasia basin is commonly recognized as a typical oceanic opening separating the Barents-Kara and Lomonosov Ridge passive margins, but geodynamic evolution of Amerasia basin are subject to much controversy, despite significant intensification of earth science researchin the recent years. A growing support to the concept of predominance in the Amerasia basin of continental crust, particularly in the area concealed under High Arctic Large Igneous Province, is

  15. Deformation of the overriding slab during incipient subduction in centrifuge modeling and its tectonic significance

    NASA Astrophysics Data System (ADS)

    Mart, Yossi; Goren, Liran; Koyi, Hemin

    2015-04-01

    Analog models of subduction-related structural deformation emphasize the significance of differences in density and friction between the adjacent plates on the distortion of the overriding slab and its possible effect on the subduction procedure. Centrifuge experiments juxtaposed miniaturized lighter and denser lithospheres, which were floating on denser but less viscous asthenosphere. The lithosphere in the tests comprised brittle and ductile strata, which showed diversified styles of deformation, while factors of equivocal tectonic significance, such as lateral push or negative buoyancy, were not introduced into the experiments. The tests show that the juxtaposition of lighter and denser lithospheres would suffice to drive the denser lithosphere as a wedge between the asthenosphere and the lighter lithosphere, and that the rate of the process would depend on the rate of friction between the slabs, as well as on differential viscosity. It seems that the reduced friction in Nature was derived from the generation of serpentinites, which could be the main agent of lubrication. The underthrusting of the denser lithosphere leads to the uplift and collapse of the edge of the lighter slab, where extension, thinning, normal faulting and rifting took place, and diapiric ascent of parts of the ductile layer of the lighter slab occurred along several rifts. The analog experiments were carried out only to the stage where the denser slab was thrust under the lighter one, but the penetration of the lithosphere into the asthenosphere was not achieved. It seems plausible therefore, that only after eclogitization, and the upward motion of serpentinites, increased the density of the underthrust slab, would it dive and penetrate into the asthenosphere. The experiments indicate the plausibility of the constraints imposed on the subduction process by the deformation of the overthrust slab. The normal faults and rifts in the overthrust block could serve as conduits for the ascent of

  16. Tectonic state: its significance and characterization in the assessment of seismic effects associated with reservoir impounding

    USGS Publications Warehouse

    Castle, R.O.; Clark, M.M.; Grantz, A.; Savage, J.C.

    1980-01-01

    Any analysis of seismicity associated with the filling of large reservoirs requires an evaluation of the natural tectonic state in order to determine whether impoundment is the basic source, a mechanically unrelated companion feature, or a triggering stimulus of the observed seismicity. Several arguments indicate that the associated seismicity is usually a triggered effect. Among the elements of tectonic state considered here (existing fractures, accumulated elastic strain, and deformational style), deformational style is especially critical in forecasting the occurrence of impoundment-induced seismicity. The observational evidence indicates that seismicity associated with impounding generally occurs in areas that combine steeply dipping faults, relatively high strain rates, and either extensional or horizontal-shear strain. Simple physical arguments suggest: (1) that increased fluid pressures resulting from increased reservoir head should enhance the likelihood of seismic activity, whatever the tectonic environment; (2) that stress changes resulting from surface loading may increase the likelihood of crustal failure in areas of normal and transcurrent faulting, whereas they generally inhibit failure in areas of thrust faulting. Comparisons with other earthquake-producing artificial and natural processes (underground explosions, fluid injection, underground mining, fluid extraction, volcanic emissions) indicate that reservoir loading may similarly modify the natural tectonic state. Subsurface loading resulting from fluid extraction may be a particularly close analogue of reservoir loading; "seismotectonic" events associated with fluid extraction have been recognized in both seismically active and otherwise aseismic regions. Because the historic record of seismicity and surface faulting commonly is short in comparison with recurrence intervals of earthquake and fault-slip events, tectonic state is most reliably appraised through combined studies of historic

  17. The origin and tectonic significance of mélanges in Eastern Sabah, Malaysia

    NASA Astrophysics Data System (ADS)

    Clennell, Ben

    Extensive chaotically disrupted rock bodies are found across Sabah in diverse tectonic settings. These units, which include broken formations, a dismembered arc-ophiolite complex and mud-matrix mélanges were formed by a combination of sedimentary, tectonic and diapiric processes. The mélanges of the eastern part of Sabah are considered to be related to basin initiation in an intra-arc setting, and are not related directly to subduction-accretion processes. The East Sabah mélanges are composed predominantly of deep water clastic sediments, deposited in the Central Sabah Basin, mixed with varying amounts of exotic ophiolitic material. The sedimentary clasts have a variety of well-developed "soft-sediment" deformation structures. These are in part inherited into the mélange from syn-sedimentary deformation, and in part generated during the mélange-forming events. The mélanges are not metamorphosed, and vitrinite reflectance data suggest that except for a few localities, a maximum temperature of less than 120°C was attained in the matrix. The ophiolitic blocks commonly have tectonic shearing fabrics associated with low temperature metamorphism. These metamorphic fabrics are incompatible with the deformation mechanisms in the sedimentary clasts and the mud matrix, and are interpreted as being inherited from shear in the ocean floor environment (e.g. fracture zones) or associated with ophiolite obduction. The similarity in clast type, deformation history and general structure also suggest that all the mélanges of the east of Sabah were formed in a series of related events during late Early Miocene and earliest Middle Miocene time. It is postulated that these events, which triggered sedimentary, diapiric and tectonic mélange-forming processes, are related to the coeval onset of extension and sea floor spreading in the southeastern Sulu Sea.

  18. Tectonic significance of Neoproterozoic magmatism of Nakora area, Malani igneous suite, Western Rajasthan, India

    NASA Astrophysics Data System (ADS)

    Kumar, Naresh; Vallinayagam, G.

    2014-05-01

    Three magmatic phases are distinguished in the Neoproterozoic Nakora Ring Complex (NRC) of Malani Igneous Suite (MIS), namely (a) Extrusive (b) Intrusive and (c) Dyke phase. Magmatism at NRC initiated with minor amount of (basic) basalt flows and followed by the extensive/voluminous acid (rhyolites-trachytes) flows. The ripple marks are observed at the Dadawari area of NRC in tuffaceous rhyolite flow which suggests the aqueous condition of flows deposition. The emplacement of the magma appears to have been controlled by a well defined NE-SW tectonic lineament and cut by radial pattern of dykes. These NE-SW tectonic lineaments are the linear zones of crustal weakness and high heat flow. The spheroidal and rapakivi structures in the Nakora acid volcanics indicate the relationship between genetic link and magma mixing. Basalt-trachyte-rhyolite association suggests that the large amount of heat is supplied to the crust from the magma chamber before the eruption. The field (elliptical/ring structures), mineralogical and geochemical characteristics of Nakora granites attest an alkaline character in their evolution and consistent with within plate tectonic setting. The emplacement of these granites and associated volcanics is controlled by ring structures, a manifestation of plume activity and cauldron subsidence, an evidence of extensional tectonic environment. NRC granites are the product of partial melting of rocks similar to banded gneiss from Kolar Schist Belt of India. The present investigations suggest that the magmatic suites of NRC rocks are derived from a crustal source and the required heat supplied from a mantle plume.

  19. Petrogenetic and tectonic significance of xenocrystic Precambrian zircon in Lower Cambrian tonalite, eastern Klamath Mountains, California

    SciTech Connect

    Wallin, E.T. )

    1990-11-01

    U-Pb analyses of zircon from a Lower Cambrian tonalite in the Yreka terrane, Klamath Mountains, California, reveal an inherited Precambrian zircon component within rocks that have generally been believed to be part of the ophiolitic Trinity complex. The isotopic data indicate that Lower Cambrian plutonic rocks in the eastern Klamath Mountains are probably not ophiolitic in origin. These Lower Cambrian rocks may be either tectonic blocks within a lower Paleozoic accretionary complex or part of a disrupted Lower Cambrian volcanoplutonic terrane.

  20. Distribution and erosion of the Paleozoic tectonic unconformities in the Tarim Basin, Northwest China: Significance for the evolution of paleo-uplifts and tectonic geography during deformation

    NASA Astrophysics Data System (ADS)

    Lin, Changsong; Yang, Haijun; Liu, Jingyan; Rui, Zhifeng; Cai, Zhenzhong; Zhu, Yongfeng

    2012-03-01

    The distribution and erosional features of the Paleozoic major tectonic unconformities in the Tarim Basin, and their genetic relation to the development of paleo-uplifts as well as the evolution of geodynamic settings, are documented in this paper based on the integral analysis of seismic, drilling, and outcrop data. During the Paleozoic, the Tarim Basin underwent three major tectonic deformation stages, which resulted in three angular unconformities and in significant changes in basin geomorphology and paleogeography. The tectonic deformation at the end of the Middle Ordovician was characterized by development of the southern central paleo-uplift, the northern depression, and the southeastern Tangguzibasi depression in the basin. The thickest denudation belts of the unconformity (Tg5-2) are distributed mainly along the thrust structural highs. A stronger deformation event took place at the end of the Late Ordovician and formed a huge uplift along the southwestern and southeastern basin margins and the western part of the Tabei uplift along the northern basin margin, producing an extensive angular unconformity (Tg5) with maximum erosion thickness of 1500-2000 m. This tectonic event resulted in an abrupt change in overall geography of the basin, from a deepwater marine environment at the late stages of the Late Ordovician to a littoral and neritic basin in the Early Silurian. The deformation that occurred at the end of the Middle Devonian was the strongest in the Paleozoic. It generated the most widespread angular unconformity (Tg3) within the basin and led to extensive erosion, with maximum denudation thickness of 3000-5000 m in the northern and northeastern parts of the basin. The topography of the basin during the late Devonian was characterized by a high in the northeast and a low in the southwest, forming an embayment basin opening to the southwest during the Early Devonian to Carboniferous. The transgression in general from southwest to northeast deposited

  1. Tectonic evolution of the Mid-Polish Trough: modelling implications and significance for central European geology

    NASA Astrophysics Data System (ADS)

    Dadlez, R.; Narkiewicz, M.; Stephenson, R. A.; Visser, M. T. M.; van Wees, J.-D.

    1995-12-01

    The Polish Basin forms the easternmost part of the Permian-Mesozoic northwest European basin. The depocentral axis of the Polish Basin, the Mid-Polish Trough (MPT), is superimposed on the boundary between the west European Phanerozoic and east European Proterozoic crustal domains, within the Trans-European Suture Zone. The presence of this fundamental crustal boundary may be paramount in structurally controlling the position of the MPT, concentrating stresses during post-Variscan wrench and extensional tectonics in central Europe. Tectonic subsidence analysis of the preserved and reconstructed stratigraphic record of the Polish Basin indicates the occurrence of an initial Late Permian-Early Triassic (255-241 Ma) 'rifting' phase that was followed by subsequent episodes of increased tectonic subsidence during the Oxfordian-Kimmeridgian (˜ 157-152 Ma) and beginning in the Cenomanian (˜97 Ma). The Oxfordian-Kimmeridgian episode is interpreted as corresponding to a second extensional event, which correlated with intersified rifting and wrench activity within the Arctic-North Atlantic rift system and along the northern Tethyan margin, while the Cenomanian may be considered a precursor of compressional deformations in the basin which culminated in basin inversion in the latest Cretaceous and Paleocene. Forward modelling results, in view of existing geophysical interpretations which show the presence of a deep Moho and a very velocity lower crustal layer beneath theMPT, suggest that Permo-Mesozoic basic development may be related at least in part to the intrusion of mantle material into and densification of the lower crust rather than exclusively to crustal extension and thinning.

  2. Seismic anisotropy of oceanic islands in East Sea of Korea from P-receiver functions: Implication for tectonic origin of the backarc basin

    NASA Astrophysics Data System (ADS)

    Kim, HyeJeong; Kim, YoungHee

    2017-04-01

    The volcanic islands (Dok, Ulleung, and Jeju islands) in East Sea of Korea sit on a backarc basin behind the Japan island arc. East Sea of Korea consists of three ocean basins (Ulleung, Japan, and Sato basins) formed since pre-Oligocene. Of the three basins, Ulleung Basin is least studied and only previously considered to include remnant continental block in the northern end of the basin, where Dok Island and Ulleung Island are located. We investigate seismic evidence of an ancient rifting in a lithospheric structure beneath the islands and eastern margin of Korean Peninsula using teleseismic P-to-S converted phases. Seismic anisotropy in particular can be a signature of the mantle flow during the subduction and extension process. By computing and modeling receiver functions, we retrieve detailed crustal and uppermost mantle structure and anisotropy, and use these geophysical results to understand the origin of the islands and the tectonic evolution of the back-arc basin. Our analysis shows three main results: (1) thicker than normal oceanic crust (˜20 km) beneath the islands; (2) a dipping Moho under Jeju and Ulleung islands; (3) a presence of lithospheric seismic anisotropy under Jeju Island. In particular, a strike of dipping Moho varies within Ulleung Island (extending 50 km laterally), which can be explained by isostacy. This evidence supports the existence of ancient continental block within northern part of Ulleung Basin. Strength of anisotropy under Jeju Island is approximately 10 % in both P- and S-wave velocities with fast symmetric axis in about N20˚ E within the crust. Three islands all show dissimilar seismological properties despite of their temporal proximity to the formation and opening of the backarc. This heterogeneous character of the region can be explained by the injection of mantle volatiles in response to the dynamics of the subduction system.

  3. Rare earth element patterns in Archean high-grade metasediments and their tectonic significance

    NASA Technical Reports Server (NTRS)

    Taylor, Stuart Ross; Rudnick, Roberta L.; Mclennan, Scott M.; Eriksson, Kenneth A.

    1986-01-01

    REE data on metasedimentary rocks from two different types of high-grade Archean terrains are presented and analyzed. The value of REEs as indicators of crustal evolution is explained; the three geologic settings (in North America, Southern Africa, and Australia) from which the samples were obtained are described; and the data are presented in extensive tables and graphs and discussed in terms of metamorphic effects, the role of accessory phases, provenance, and tectonic implications (recycling, the previous extent of high-grade terrains, and a model of Archean crustal growth). The diversity of REE patterns in shallow-shelf metasediments is attributed to local provenance, while the Eu-depleted post-Archean patterns are associated with K-rich plutons from small, stable early Archean terrains.

  4. Hemorrhagic Fever with Renal Syndrome (HFRS) and Infectious Diseases of Military Significance in Korea

    DTIC Science & Technology

    1993-06-21

    were conducted throughout Korea to better characterize the distribu- tion of militarily important human infections. Antibodies to hantaviruses were...of antibodies to hantaviruses , rickettsiae, and hepatitis viruses’. Surveys were carried out in the rural areas surrounding Chorwon near the "Iron...20 yrs). The prevalence of antibodies to hantaviruses was 6.2" overall (Q30 yrs = 14.6%). Scrub typhus antibodies were present in 5% of individuals

  5. Detrital modes of the Pyeongan Supergroup (Late Carboniferous Early Triassic) sandstones in the Samcheog coalfield, Korea: implications for provenance and tectonic setting

    NASA Astrophysics Data System (ADS)

    Lee, Yong Il; Sheen, Dong-Hee

    1998-08-01

    Medium to coarse sandstones of the Carboniferous to Early Triassic Pyeongan Supergroup in the Samcheog coalfield, Korea, were studied to infer the provenance and tectonic settings of the source areas. Sandstone detrital modes change upwards stratigraphically. Sandstone types from the Manhang to Dosagog formations low to middle in the sequence are quartzarenite, and sublitharenite to litharenite, whereas sandstones of the Gohan and Donggo formations high in the sequence are feldspathic litharenite and arkose, respectively. Using various ternary diagrams, the provenance of the Manhang to Gohan formations is suggested to be a recycled orogen setting. Some Gohan Formation sandstones plot within the arc-related setting field, and the Donggo Formation sandstones plot within both continental block and recycled orogen fields. Results of quartz grain petrography are consistent with those of detrital modes. Quartz in sandstones of all units except the Donggo Formation indicates derivation from low-rank metamorphic sources. Quartz in Donggo sandstones was derived from medium- to high-rank metamorphic and plutonic source rocks. Considering the sandstone composition and palaeocurrent data, the Pyeongan Supergroup probably was deposited in a molasse foreland basin and was derived from a synbasinal orogenic belt, probably the Akiyoshi orogen located in southwest Japan.

  6. Thermochronological Evolution of the Sierra Maestra, Cuba: Significance for Caribbean Tectonics

    NASA Astrophysics Data System (ADS)

    Rojas-Agramonte, Y.; Neubauer, F.; Handler, R.; Hejl, E.; Bojar, A.; Garcia-Delgado, D. E.

    2002-12-01

    The Sierra Maestra in southeastern Cuba comprises Paleogene intraoceanic volcanic arc sequences which have been accreted to the North American continental margin during the late Middle Eocene, during the final stages of collision with the Caribbean plate. Geochronological analysis and geobarometric investigations on samples from Eocene granitoids constrain the cooling history and tectonic evolution of the region. Granitoids intruded at pressures ranging from 1.8 to 3.0 kbar, corresponding to depths of approx. 4.5-8 km. 40Ar/39Ar dating of biotite yielded ages of 50+/-2 to 54+/-4 Ma (2-sigma errors), indicating cooling through ca. 300 oC. Zircon and apatite fission track ages range from 32+/-3 to 46+/-4 Ma and 31+/-10 to 44+/-13 Ma, respectively, and date cooling through 250+/-50 oC and 110+/-20 oC. These data suggest fast cooling and exhumation of the granitoids during collisional processes in the Eocene. Apatite track length measurements show a bimodal frequency distribution suggesting initial very fast cooling between 45 and 40 Ma, down to 120 oC, followed by a period of 30 Ma where almost no variation occurred in the temperature. Final cooling occurred since 12 Ma and is probably related to transform faulting along the southern margin of the Sierra Maestra. We propose that slab breakoff of the subducting North American plate occurred during the final stages of collision between the North American and Caribbean plates, and we argue, therefore, that the granitoids cooled and were exhumed as a consequence of this process and eastward migration of the slab-tear. Several lines of evidence support this model: (1) Published cooling and exhumation ages of the granitoids are younging from west to east, with old ages (ca. 56 Ma) in the west and young ones in the east (ca. 49 Ma). (2) Subsequent rapid cooling through 300 to 110 °C occurred also partly in the Middle to early Late Eocene, suggesting rapid uplift and cooling of the entire crust as granitoids intruded at a

  7. Density structure of the lithosphere in the southwestern United States and its tectonic significance

    USGS Publications Warehouse

    Kaban, M.K.; Mooney, W.D.

    2001-01-01

    We calculate a density model of the lithosphere of the southwestern United States through an integrated analysis of gravity, seismic refraction, drill hole, and geological data. Deviations from the average upper mantle density are as much as ?? 3%. A comparison with tomographic images of seismic velocities indicates that a substantial part (>50%) of these density variations is due to changes in composition rather than temperature. Pronounced mass deficits are found in the upper mantle under the Basin and Range Province and the northern part of the California Coast Ranges and adjacent ocean. The density structure of the northern and central/southern Sierra Nevada is remarkably different. The central/southern part is anomalous and is characterized by a relatively light crust underlain by a higher-density upper mantle that may be associated with a cold, stalled subducted plate. High densities are also determined within the uppermost mantle beneath the central Transverse Ranges and adjoining continental slope. The average density of the crystalline crust under the Great Valley and western Sierra Nevada is estimated to be up to 200 kg m~3 higher than the regional average, consistent with tectonic models for the obduction of oceanic crust and uppermost mantle in this region.

  8. Nature of ophiolite occurrences along the eastern margin of the Indian plate and their tectonic significance

    NASA Astrophysics Data System (ADS)

    Sengupta, S.; Ray, K. K.; Acharyya, S. K.; de Smeth, J. B.

    1990-05-01

    Upper Mesozoic to lower Eocene ophiolitic rocks occur in two parallel belts along the eastern margin of the Indian plate. The eastern belt passes through central Burma, Sumatra, and Java, and coincides with a zone of gravity highs resulting from steeply dipping mafic rocks. It denotes the locus of the subduction where these ophiolites were accreted just prior to middle Eocene time. In contrast, the western belt, which passes through Nagaland, Manipur, western Burma, and Andaman, is flanked to the east by a negative gravity anomaly zone. In it the ophiolites occur as rootless, subhorizontal bodies, tectonically overlying Eocene-Oligocene flysch sedimentary rocks. They are inferred to be nappes that propagated westward from the eastern belt during late Oligocene terminal collision of the Indian and Eurasian continental blocks. Ophiolite occurrences in Andaman and Mentawai islands belonging to the western belt are generally linked with active subduction west of the island arc. This subduction began only in late Miocene time, and thus it could not have produced the ophiolites, which had been emplaced on land much earlier.

  9. Petrochemistry and tectonic significance of Lower Cretaceous Barros Arana Formation basalts, southernmost Chilean Andes

    NASA Astrophysics Data System (ADS)

    Stern, C. R.; Mohseni, P. P.; Fuenzalida, P. R.

    The Lower Cretaceous Barros Arana Formation (Albian, hornblende KAr age of 104 Ma), in the Magallanes region of Chile, consists of a sequence of spilitized clinopyroxene- and amphibole-bearing mafic dikes and lavas, and volcaniclastic breccias, occurring within the sedimentary infill of the Rocas Verdes marginal basin and its eastward extension onto the Cretaceous continental platform. Although the original alkali and alkaline earth element concentrations of the basaltic lavas and dikes have been altered by spilitization, the presence of relict pargasitic amphibole phenocrysts, the absence of orthopyroxene, and high LREE contents and LREE/HREE ratios imply mildly alkaline affinities for these basalts. Their low TiO 2 and HFSE (Zr, Nb, Ta, and Hf) contents and high LREE/HFSE ratios suggest affinities with convergent plate boundary arc magmas. The Barros Arana basalts are interpreted as mafic members of the mildly alkaline shoshonitic rock suite of subduction-related arcs. They may have formed as subduction geometry began to undergo the changes (flattening) that ultimately led to the initiation of the closure, deformation, and uplift of the Rocas Verdes basin by the late or post-Albian. The low initial 87Sr/ 86Sr (0.7031) and high initial 143Nd/ 144Nd (0.51277) of the basalts indicate that a generally extensional tectonic regime east of the main calc-alkaline arc allowed eruption of these mafic shoshonites without interaction with continental crust (in contrast to the contemporaneous plutons of the Patagonian batholith).

  10. Public health significance of major genotypes of Salmonella enterica serovar Enteritidis present in both human and chicken isolates in Korea.

    PubMed

    Kang, Min-Su; Oh, Jae-Young; Kwon, Yong-Kuk; Lee, Deog-Yong; Jeong, Ok-Mi; Choi, Byung-Kook; Youn, So-Youn; Jeon, Byung-Woo; Lee, Hye-Jin; Lee, Hee-Soo

    2017-02-17

    Salmonella enterica serovar Enteritidis is one of the most common serotypes implicated in Salmonella infections in both humans and poultry worldwide. It has been reported that human salmonellosis is mainly associated with the consumption of poultry products contaminated with serovar Enteritidis. The present study was to extensively analyze the public health risk of serovar Enteritidis isolates from chickens in Korea. A total of 127 chicken isolates were collected from clinical cases, on-farm feces, and chicken meat between 1998 and 2012 and 20 human clinical isolates were obtained from patients with diarrhea between 2000 and 2006 in Korea. To characterize the isolates from chickens and humans, we compared the pulsed-field gel electrophoresis (PFGE) patterns and multilocus variable-number tandem-repeat analysis (MLVA) profiles of the isolates. We further characterized representative isolates of different genotypes using a DNA microarray. PFGE revealed 28 patterns and MLVA identified 16 allelic profiles. The DNA microarray showed high genetic variability in plasmid regions and other fimbrial subunits of the isolates although the virulence gene contents of isolates from the same source and/or of the same genotype were unrelated. PFGE and MLVA showed that major genotypes were present in both human and chicken isolates. This result suggests that chickens in Korea pose a significant risk to public health as a source of serovar Enteritidis as has been noted in other countries.

  11. The Cerro Aguas Calientes caldera, NW Argentina: An example of a tectonically controlled, polygenetic collapse caldera, and its regional significance

    NASA Astrophysics Data System (ADS)

    Petrinovic, I. A.; Martí, J.; Aguirre-Díaz, G. J.; Guzmán, S.; Geyer, A.; Paz, N. Salado

    2010-07-01

    Polygenetic, silicic collapse calderas are common in the central Andes. Here we describe in detail the Cerro Aguas Calientes caldera in NW Argentina, which comprises two caldera-forming episodes that occurred at 17.15 Ma and 10.3 Ma. We analyse the significance of its structural setting, composition, size and the subsidence style of both caldera episodes. We find that the caldera eruptions had a tectonic trigger. In both cases, an homogeneous dacitic crystal-rich (>60 vol.% of crystals) reservoir of batholithic size became unstable due to the effect of increasing regional transpression, which favoured local dilation through minor strike-slip faults from which ring faults nucleated and permitted caldera collapse. Both calderas are similar in shape, location and products. The 17.15 Ma caldera has an elliptical shape (17 × 14 km) elongated in a N30° trend; both intracaldera and extracaldera ignimbrites covered an area of around 620 km 2 with a minimum volume estimate of 140 km 3 (DRE). The 10.3 Ma episode generated another elliptical caldera (19 × 14 km), with the same orientation as the previous one, from which intracaldera and outflow ignimbrites covered a total area of about 1700 km 2, representing a minimum eruption volume of 350 km 3(DRE). In this paper we discuss the significance of the Cerro Aguas Calientes caldera in comparison with other well known examples from the central Andes in terms of tectonic setting, eruption mechanisms, and volumes of related ignimbrites. We suggest that our kinematic model is a common volcano-tectonic scenario during the Cenozoic in the Puna and Altiplano, which may be applied to explain the origin of other large calderas in the same region.

  12. The Cerro Aguas Calientes caldera, NW Argentina: an example of a tectonically controlled, polygenetic, collapse caldera, and its regional significance

    NASA Astrophysics Data System (ADS)

    Petrinovic, Ivan A.; Martí, Joan; Aguirre-Diaz, Gerardo J.; Guzmán, Silvina R.; Geyer, Adelina; Grosse, Pablo; Salado Paz, Natalia

    2010-05-01

    Polygenetic, silicic collapse calderas such as Cerro Galán, Pastos Grandes, La Pacana, Vilama, Negra Muerta, Farallón Negro, Cerro Guacha, among others are common in the central Andes. Here we describe in detail the Cerro Aguas Calientes caldera in NW Argentina, which comprises two caldera-forming episodes occurred at 17.15 Ma and 10.3 Ma, respectively. We analyse the significance of its structural setting, composition, size and the subsidence style of both caldera episodes. Our results reveal that the caldera eruptions had a tectonic trigger. In both cases, an homogeneous dacitic crystal-rich (>60 vol. % of crystals) reservoir of batholitic size became unstable due to the effect of increasing regional transpression, favouring local dilation throughout minor strike slip faults from which ring faults nucleated and permitted caldera collapse. Both episodes are similar in shape, location and products of the resulting calderas. The 17.15 Ma caldera has an elliptical shape (17 × 14 km) and is elongated in a N30° trend; both intracaldera and extracaldera ignimbrites covered an area of around 620 km2 with a minimum volume estimate of 138 km3 (DRE). The 10.3 Ma episode generated another elliptical caldera (19 ×14 km), with the same orientation as the previous one, from which intracaldera and outflow ignimbrites covered a total area of about 1,700 km2, representing a minimum eruption volume of 341 km3 (DRE). In this work we discuss the significance of the Cerro Aguas Calientes caldera in comparison with other well known examples from the central Andes in terms of tectonic setting, eruption mechanisms, and volumes of related ignimbrites. We suggest that our kinematic model is a common volcano-tectonic scenario during the Cenozoic in the Puna and Altiplano, which may be applied to explain the origin of other large calderas in the same region.

  13. Tectonic significance of bimodal volcanism in the Archean Michipicoten greenstone belt, Ontario

    SciTech Connect

    Sylvester, P.J.

    1985-01-01

    In the lower volcanic cycle (2750 Ma old) of the Michipicoten greenstone belt, Ontario, a basal mafic unit (MV1) consisting mainly of basalt-basaltic andesite (49.4-56.4 wt.% SiO/sub 2/, 8.77-12.36 wt.% FeO/sub t/) with enriched ((La/Sm)/sub n/=1.9-2.6, Th=2.0-4.1 ppm, Sr=310-570 ppm) and depleted ((La/Sm)/sub n/=0.55-1.07, Th=0.16-0.71 ppm, Sr<250 ppm) trace element characteristics is locally overlain by a felsic unit (FV1) dominated volumetrically by rhyolite (71.9-79.6 wt.% SiO/sub 2/) and subordinate dacite (62.2-68.8 wt.% SiO/sub 2/). The mafic rocks are pillowed, massive flows and hyaloclastites suggesting subaqueous emplacement, whereas the felsic rocks are dominantly subaerial to shallow subaqueous pyroclastic deposits. The basalts of MV1 are similar chemically to modern tholeiites formed in primitive island arc/marginal basin complexes. In contrast, the rhyolites and dacites of FV1 exhibit the calc-alkaline chemical characteristics and rock associations typical of some continental inner arc volcanics. The juxtaposition of primitive island arc/marginal basin and continental inner arc tectonic settings occurs at the present time in the Tonga-Kermadec-New Zealand island arc. According to this model, MV1 is analogous to the basalt/basaltic andesite-dominated volcanism of the Tonga-kermadec island arc/Lau back-arc basin, whereas FV1 is the equivalent of the voluminous rhyolitic ignimbrites of the Taupo inner arc basin. The model suggests that the lower volcanic cycle of the Michipicoten belt formed on a basement consisting of small blocks of continental crust surrounded by oceanic crust.

  14. Structural geology and tectonic significance of foreland thrust belts, Tarim and Junggar basins, northwest China

    SciTech Connect

    McKnight, C.L.; Chu, J.; Corroll, A.R.; Hendrix, M.S.; Wang, X.; Graham, S.A.; Liang, Y.H.; Wang, Z.X.; Xiao, X.

    1989-03-01

    The Kalpin uplift, located on the northwestern margin of the Tarim basin is characterized by a series of thin, southeast-vergent thrust plates modified by strike-slip faults. Each thrust plate repeats a sedimentary sequence consisting of upper Proterozoic through Permian shallow marine to nonmarine carbonates and clastics. Tertiary rocks as young as Neogene are affected by the deformation. The most basinward thrust sheet abuts the Bachu uplift, an older structural feature trending almost perpendicular to the thrusts. Sedimentary rocks as old as late Proterozoic are exposed in the Bachu uplift, which apparently represents a west-vergent Late Silurian to Early Devonian thrust belt. An unconformable Silurian-Devonian contact, the presence of Devonian red beds, and another unconformable contact separating Devonian from Upper Carboniferous strata support the interpretation of a middle Paleozoic deformational event. Another unconformity, at the Carboniferous-Permian boundary, apparently coincides with the time of collision of the Tarim craton with the southern margin of central Asia. The Shihezi fold trend, located in the southern Junggar basin, consists of three lines of surface anticlines trending parallel to the axis of the Urumqi foredeep. A thick sequence of Mesozoic and Cenozoic nonmarine sedimentary rocks accumulated in the growing foredeep. Mesozoic and Paleogene strata are deformed in the southern foldbelt, with Jurassic rocks forming the cores of these thrusted anticlines. The Qigu oil field is located in this southern belt. Deformed Neogene and Quaternary strata are exposed in the thrusted anticlines of the middle and northern foldbelts. The Dushanzi oil field is located in the northern belt. The episodic development of compressional structures in northwestern China documents the accretion of a number of tectonic units to the growing southern margin of central Asia through time.

  15. Growth faults and salt tectonics in Houston diapir province: relative timing and exploration significance

    SciTech Connect

    Ewing, T.E.

    1983-09-01

    Oil and gas accumulation in Gulf Coast Tertiary strata is contolled mainly by regional growth faults and by salt-related structures. Salt forms the most prominent set of structures in the Houston diapir province of southeast Texas. Recent work in three study areas shows that the Tertiary growth-fault trends, so well displayed along strike to the south-west, continue through this salt basin as well, but they have been deformed by later salt movement. In the Katy area, seismic data disclose early (pre-Wilcox) salt pillows downdip of the Cretaceous reef trend. Salt stocks were injected upward from the pillows during Clayborne deposition, and were flanked by deep withdrawal basins and turtle structures. In Brazoria County, a major lower Frio growth-fault trend affecting the Houston delta system, was deformed by later salt domes, by a salt-withdrawal basin, and by a possible turtle structure at Chocolate Bayou. A productive geopressured aquifer exists in the salt-withdrawal basin bounded by the previously formed growth faults. In Jefferson County, in contrast, salt-tectonic activity and growth faulting appear to have been coeval. Early salt-cored ridges continued to rise throughout Frio deposition; growth faults occur both updip and downdip. Hydrocarbons accumulated over the salt domes in growth-fault anticlines and in stratigraphic traps. Recognition that shelf-margin growth faulting preceded the development of the present pattern of domes and basins has important implications for hydrocarbon exploration. Growth faults may be migration paths for hydrocarbons; furthermore, early formed traps, distorted by salt movement, may still be found to contain hydrocarbons.

  16. Detrital zircon U-Pb geochronology and tectonic implications of the Paleozoic sequences in western South Korea

    NASA Astrophysics Data System (ADS)

    Kim, Sung Won; Kwon, Sanghoon; Santosh, M.; Cho, D. L.; Ryu, In-Chang

    2014-12-01

    The Middle Paleozoic metasedimentary sequences of the western Gyeonggi Massif (Taean Formation and Wolhyeonri Complex), Imjingang Belt, and southwestern Okcheon Belt, provide clues to the successive tectonic events that occurred during the evolution of the Korean Peninsula. In this study, we present SHRIMP U-Pb ages of detrital zircon grains from the metasandstones of the Taean Formation and Yeoncheon Group of the Imjingang Belt and from quartzites in three Paleozoic formations of the southwestern Okcheon Belt. The zircon grains from all of the samples yielded similar U-Pb age spectra of Paleoarchean/Neoarchean to Middle Paleozoic, with a dominant age population within the Paleozoic. The maximum ages of deposition estimated from the youngest dominant concordant detrital zircons were 431-457 Ma for the western Gyeonggi Massif and Imjingang Belt, and 380-355 Ma for the southwestern Okcheon Belt. Permian metamorphic zircon overgrowths correlated with subduction prior to the Triassic collision were also found. Middle Paleozoic metamorphic zircon overgrowths that can be compared to those of the Yunkai-Wuishan Orogenic Belt of the Cathaysia Block were indentified in the Wolhyeonri Complex. The dominant zircon populations of this study and the available data for the Korean Peninsula compare well with those from the Yangtze Block, Cathaysia Block, and Qilian-Qinling Orogenic Belt, which were located at the northeastern margin of eastern Gondwana during the Early Paleozoic.

  17. Early to Middle Ordovician back-arc basin in the southern Appalachian Blue Ridge: characteristics, extent, and tectonic significance

    USGS Publications Warehouse

    Tull, James; Holm-Denoma, Christopher S.; Barineau, Clinton I.

    2014-01-01

    Fault-dismembered segments of a distinctive, extensive, highly allochthonous, and tectonically significant Ordovician (ca. 480–460 Ma) basin, which contains suites of bimodal metavolcanic rocks, associated base metal deposits, and thick immature deep-water (turbiditic) metasediments, occur in parts of the southern Appalachian Talladega belt, eastern Blue Ridge, and Inner Piedmont of Alabama, Georgia, and North and South Carolina. The basin's predominantly metasedimentary strata display geochemical and isotopic evidence of a mixed provenance, including an adjacent active volcanic arc and a provenance of mica (clay)-rich sedimentary and felsic plutonic rocks consistent with Laurentian (Grenvillian) upper-crustal continental rocks and their passive-margin cover sequences. Geochemical characteristics of the subordinate intercalated bimodal metavolcanic rocks indicate formation in a suprasubduction environment, most likely a back-arc basin, whereas characteristics of metasedimentary units suggest deposition above Neoproterozoic rift and outer-margin lower Paleozoic slope and rise sediments within a marginal basin along Ordovician Laurentia's Iapetus margin. This tectonic setting indicates that southernmost Appalachian Ordovician orogenesis (Taconic orogeny) began as an extensional accretionary orogen along the outer margin of Laurentia, rather than in an exotic (non-Laurentian) arc collisional setting. B-type subduction polarity requires that the associated arc-trench system formed southeast of the palinspastic position of the back-arc basin. This scenario can explain several unique features of the southern Appalachian Taconic orogen, including: the palinspastic geographic ordering of key tectonic elements (i.e., back-arc, arc, etc.), and a lack of (1) an obducted arc sensu stricto on the Laurentian margin, (2) widespread Ordovician regional metamorphism, and (3) Taconic klippen to supply detritus to the Taconic foreland basin.

  18. Peralkaline granitoid magmatism in the Mongolian-Transbaikalian Belt: Evolution, petrogenesis and tectonic significance

    NASA Astrophysics Data System (ADS)

    Jahn, B. M.; Litvinovsky, B. A.; Zanvilevich, A. N.; Reichow, M.

    2009-12-01

    The Central Asian Orogenic Belt (CAOB) is well-known for its massive generation of juvenile crust in the Phanerozoic. In eastern CAOB, voluminous peralkaline and alkaline (alkali-feldspar) granitoids and genetically related bimodal volcanics were emplaced in three stages from Early Permian to late Mesozoic: 295-270 Ma, 230-190 Ma and 150-120 Ma. They occur as huge granitoid belts in extensional tectonic settings and form a complex network of about 12 million km 2 in area. Among them the 2500 km-long Mongolian-Transbaikalian Belt (MTB) is the most spectacular and it comprises more than 350 granite-syenite plutons and stocks, with numerous co-genetic volcanic fields. The three stages of granitoids have similar chemical compositions but show temporal variation in Nd isotopic composition. Initial ɛNd( T) values range from - 1 to - 5 for the Early Permian, 0 to + 4 for the early Mesozoic, and - 2 to - 3.5 for the late Mesozoic granitoids. The negative ɛNd( T) values observed in the MTB are not typical of the CAOB granitoids, which are generally characterized by positive values. However, several pieces of evidence suggest that the MTB peralkaline and alkali feldspar granitoids were produced from enriched mantle-derived sources. The evidence includes: (1) Felsic and mafic rocks formed in the same stage have similar initial Nd-Sr isotopic ratios and Sm-Nd model ages ( TDM). (2) The granitoid belts extend over thousands of kilometers and intersect distinct crustal provinces, but no correlation is found in chemical compositions between the granitoids and country rocks. (3) The abundant syenites are considered to be cogenetic or, in some cases, parental to the granites. Experimental and isotope data argue for the derivation of syenites from an enriched mantle source, thus the granites (and comendites) are regarded as mantle-derived. (4) A study of melt inclusions in quartz phenocrysts of comendite indicates a high liquidus temperature of 1000-1100 °C for the magma

  19. Age and tectonic significance of volcanic rocks in the northern Los Angeles Basin, California

    USGS Publications Warehouse

    McCulloh, Thane H.; Fleck, Robert J.; Denison, Rodger E.; Beyer, Larry A.; Stanley, Richard G.

    2002-01-01

    Volcanic rocks, mostly basalts and some andesites, are interbedded with middle Miocene strata and are overlain by younger rocks throughout the greater part of the Los Angeles Basin, California. Roughly correlative flows, previously dated radiometrically (or paleontologically) at about 16.4 to 10.7 Ma, crop out in five separate regions around the basin perimeter. Los Angeles Basin volcanic rocks have special meaning because they offer clues to tectonomagmatic events associated with onset of clockwise transrotation of the western Transverse Ranges region and to the timing and locus of the initial basin opening. Whole-rock 40Ar/39Ar dating of near-tholeiitic olivine basalts of the Topanga Formation (Hoots, 1931) from three sites in the easternmost Santa Monica Mountains, combined with 87Sr/86Sr dating of fossil carbonates from interstratified marine beds at nine sites, establish a new age of 17.4 Ma for these oldest known Topanga-age volcanics of the Los Angeles Basin. We also record three new 40Ar/39Ar ages (15.3 Ma) from andesitic flows of the lower Glendora Volcanics at the northeast edge of the basin, 70 km east of the Santa Monica Mountains. A whole-rock determination of 17.2±0.5 Ma for nearby altered olivine basalt in the unfossiliferous Glendora volcanic sequence is questionable because of a complex 40Ar/39Ar age spectrum suggestive of 39Ar recoil, but it may indicate an older volcanic unit in this eastern area. We hypothesize that the 17.4-Ma volcanics in the eastern Santa Monica Mountains are an early expression of deep crustal magmatism accompanying the earliest extensional tectonism associated with rifting. The extremely thick younger volcanic pile in the western and central parts of the range may suggest that this early igneous activity in the eastern area was premonitory. Paleomagnetic declination data are needed to determine the pre-transrotational orientation of the eastern Santa Monica Mountains volcanic sequence. The new age determinations do not

  20. Stratigraphy, geochemistry and tectonic significance of the Oligocene magmatic rocks of western Oaxaca, southern Mexico

    USGS Publications Warehouse

    Martiny, B.; Martinez-Serrano, R. G.; Moran-Zenteno, D. J.; MacIas-Romo, C.; Ayuso, R.A.

    2000-01-01

    the volcanic rocks, from 0.7042 to 0.7046 and 0 +2.6. The range of these isotope ratios and those reported for the basement rocks in this region suggest a relatively low degree of old crustal involvement for most of the studied rocks. The Pb isotopic compositions of the Tertiary magmatic rocks also show a narrow range [(206Pb/204Pb) = 18.67-18.75; (207Pb/204Pb) = 15.59-15.62; (208Pb/204Pb) = 38.44-38.59], suggesting a similar source region for the volcanic and plutonic rocks. Trace elements and isotopic compositions suggest a mantle source in the subcontinental lithosphere that has been enriched by a subduction component. General tectonic features in this region indicate a more active rate of transtensional deformation for the inland volcanic region than along the coastal margin during the main events of Oligocene magmatism. The lower degree of differentiation of the inland volcanic sequences, particularly the upper unit of the northern sector, compared to the plutons of the coastal margin, suggests that the differentiation of the Tertiary magmas in southern Mexico was controlled to a great extent by the characteristics of the different strain domains. (C) 2000 Elsevier Science B.V. All rights reserved.

  1. Comparison of evolution and tectonic significance of the Pindos and Vourinos ophiolite suites, northern Greece

    NASA Astrophysics Data System (ADS)

    Ross, John V.; Zimmerman, Jay

    1996-05-01

    The Pindos ophiolite, located on the western edge of the Sub-Pelagonian (Othris) zone, comprises a complex series of westward-verging thrust sheets dominantly composed of peridotite tectonite, phaneritic mafic and leucocratic rocks, and pillow lavas. Harzburgite tectonites from part of the east-central thrust sheet (Dramala Complex) show three well developed foliations. The oldest, compositional layering (S 0), has been isoclinally folded, and preferred orientations of elongate grains and aggregates of olivine and orthopyroxene parallel to the axial surfaces of the isoclines define the second foliation (S 1). Spinel lineations parallel fold axes of the isoclinal folds. Thermometric calculations from mineral compositions and grain sizes of olivines and pyroxenes associated with the oldest preserved foliations (compositional layering, S 0 = S 1) indicate that rocks of the tectonite suite equilibrated at depths of between 45 and 60 km, at temperatures between 1210°C and 925°C and at differential stresses from 5 to 10 MPa. In general, rocks indicative of higher temperatures of equilibration formed at lower values of differential stress. The third, and youngest, foliation is defined by bands of fine-grained olivine and pyroxene mylonite that cut across older structural elements. Mylonites equilibrated at temperatures between 650°C and 710°C, presumably indicative of shallower depths (30-20 km) than the older foliations, accompanied by differential stresses ranging from 200 to 300 MPa, and probably formed during obduction of the complex. The sense and orientation of shear determined from kinematic indicators within the mylonitic zones indicate an updip displacement vector inclined at an angle of 20° to 40° toward 016°, suggesting obduction to the east-northeast relative to the present position of the Pindos ophiolite. There is no direct evidence for the amount of rotation about a vertical axis that may have occurred during obduction or later tectonic transport

  2. Paleomagnetism of the Tertiary Clarno Formation of central Oregon and its significance for the tectonic history of the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Gromme, C. Sherman; Beck, Myrl E., Jr.; Wells, Ray E.; Engebretson, David C.

    1986-12-01

    The Clarno Formation, a mostly Eocene and partly early Oligocene sequence of andesitic lavas and volcaniclastic rocks, is the oldest Tertiary formation exposed in north central Oregon. Remanent magnetization directions at 46 sites in the lavas provide a paleomagnetic pole at 84°N, 278°E with a 95% confidence cone of 7°. Comparison of this pole with the North American reference pole for Eocene time indicates that the Clarno Formation has rotated 16° clockwise with an uncertainty of 10° but has undergone no significant latitudinal displacement. Further comparison with paleomagnetic data from the Miocene Columbia River Basalt Group and Steens Basalt shows that large-scale block rotations in the eastern Columbia Embayment ceased sometime between 38 m.y. and 15 m.y. A paleogeographic reconstruction for 38 m.y. is offered which is consistent with the observed rotation of the Clarno and with the other paleomagnetic data from the Pacific Northwest, which are briefly reviewed. This reconstruction shows that it is possible to account for virtually all of the paleomagnetically indicated rotations in pre-Miocene Tertiary rocks of the Pacific Northwest by an extensional tectonic model. As a consequence, only part of the rotations in the pre-Tertiary rocks of the eastern Columbia Embayment need to be the result of accretionary tectonics. The initiation of magmatism in the eastern Columbia Embayment that is represented by the Clarno Formation itself may have been contemporaneous with the beginning of crustal extension in the Pacific Northwest.

  3. Paragenesis and tectonic significance of base and precious metal occurrences along the San Andreas fault at Point Delgada, California.

    USGS Publications Warehouse

    McLaughlin, R.J.; Sorg, D.H.; Morton, J.L.; Theodore, T.G.; Meyer, C.E.; Delevaux, M.H.

    1985-01-01

    The mineralogy, geochemistry and origin of sulphide veins along cross faults in the San Andreas fault system are described and cited for a natural history of local plate tectonics and for 'a detailed understanding of the role of major strike-slip faults in the formation and tectonic translation of hydrothermal ore deposits'. -G.J.N.

  4. Clinical Significance of Component Allergens in Fagales Pollen-Sensitized Peanut Allergy in Korea

    PubMed Central

    Park, Kyung Hee; Son, Young Woong; Lee, Sang Chul; Jeong, Kyunguk; Sim, Da Woon; Park, Hye Jung; Lee, Sooyoung; Lee, Jae-Hyun

    2016-01-01

    Purpose Clinical features of peanut allergy can range from localized to systemic reactions. Because peanut and birch pollen have cross-reactivity, peanut can lead to localized allergic reaction in Fagales pollen-sensitized oral allergy syndrome (OAS) patients without peanut sensitization per se. The purpose of this study was to discriminate true peanut food allergy from cross-reactive hypersensitivity in birch-sensitized peanut allergy. Methods Birch-sensitized (n=81) and peanut anaphylaxis patients (n=12) were enrolled. Peanut-related allergic reactions and sensitization profiles were examined. Specific IgE to Fagales tree pollens (birch, oak), peanut, and their component allergens (Bet v 1, Bet v 2, Ara h 1, Ara h 2, Ara h 3, Ara h 8, and Ara h 9) were evaluated. Based on these specific IgEs and clinical features, the patients were classified into 4 groups: group 1 (Fagales pollen allergy without OAS), group 2 (Fagales pollen allergy with OAS), group 3 (OAS with peanut anaphylaxis), and group 4 (peanut anaphylaxis). Results After peanut consumption, one-third of OAS patients experienced oral symptoms not associated with peanut sensitization. Ara h 1 or Ara h 2 was positive in peanut anaphylaxis patients, whereas Ara h 8 was positive in OAS patients. There were 4 patients with both peanut anaphylaxis and OAS (group 3). Both Ara h 2 and Ara h 8 were positive in these patients. Foods associated with OAS in Korea showed unique patterns compared to Westernized countries. Conclusions Ara h 2 and Ara h 8 may be important component allergens for discriminating peanut allergy. PMID:27582401

  5. Clinical Significance of Component Allergens in Fagales Pollen-Sensitized Peanut Allergy in Korea.

    PubMed

    Park, Kyung Hee; Son, Young Woong; Lee, Sang Chul; Jeong, Kyunguk; Sim, Da Woon; Park, Hye Jung; Lee, Sooyoung; Lee, Jae Hyun; Park, Jung Won

    2016-11-01

    Clinical features of peanut allergy can range from localized to systemic reactions. Because peanut and birch pollen have cross-reactivity, peanut can lead to localized allergic reaction in Fagales pollen-sensitized oral allergy syndrome (OAS) patients without peanut sensitization per se. The purpose of this study was to discriminate true peanut food allergy from cross-reactive hypersensitivity in birch-sensitized peanut allergy. Birch-sensitized (n=81) and peanut anaphylaxis patients (n=12) were enrolled. Peanut-related allergic reactions and sensitization profiles were examined. Specific IgE to Fagales tree pollens (birch, oak), peanut, and their component allergens (Bet v 1, Bet v 2, Ara h 1, Ara h 2, Ara h 3, Ara h 8, and Ara h 9) were evaluated. Based on these specific IgEs and clinical features, the patients were classified into 4 groups: group 1 (Fagales pollen allergy without OAS), group 2 (Fagales pollen allergy with OAS), group 3 (OAS with peanut anaphylaxis), and group 4 (peanut anaphylaxis). After peanut consumption, one-third of OAS patients experienced oral symptoms not associated with peanut sensitization. Ara h 1 or Ara h 2 was positive in peanut anaphylaxis patients, whereas Ara h 8 was positive in OAS patients. There were 4 patients with both peanut anaphylaxis and OAS (group 3). Both Ara h 2 and Ara h 8 were positive in these patients. Foods associated with OAS in Korea showed unique patterns compared to Westernized countries. Ara h 2 and Ara h 8 may be important component allergens for discriminating peanut allergy.

  6. Provenance and U-Pb geochronology of the Upper Cretaceous El Chanate Group, northwest Sonora, Mexico, and its tectonic significance

    USGS Publications Warehouse

    Jacques-Ayala, C.; Barth, A.P.; Wooden, J.L.; Jacobson, C.E.

    2009-01-01

    The Upper Cretaceous El Chanate Group, northwest Sonora, Mexico, is a 2.8km thick clastic sedimentary sequence deposited in a continental basin closely related to volcanic activity. It consists of three formations: the Pozo Duro (oldest), the Anita, and the Escalante (youngest). Petrographic study, conglomerate pebble counts, and U-Pb geochronology of detrital zircons were performed to determine the source and age of this sequence, and to interpret its tectonic setting. In the sandstones of all three formations, the most abundant grains are those of volcanic composition (Q38F22L 40, Q35F19L46, and Q 31F22L47, respectively). The Pozo Duro Formation includes well-rounded quartz-arenite clast conglomerates, whereas conglomerates of the two upper units have clasts predominantly of andesitic and rhyolitic composition. The most likely source for these sediments was the Jurassic volcanic arc exposed in northern Sonora and southern Arizona. Zircons from five sandstone samples define two main age groups, Proterozoic and Mesozoic. The first ranges mostly from 1000 to 1800Ma, which suggests the influence of a cratonic source. This zircon suite is interpreted to be recycled and derived from the same source area as the quartz-rich sandstone clasts in the basal part of the section. Mesozoic zircons range from Triassic to Late Cretaceous, which confirms the proposed Late Cretaceous age for the sequence, and also corroborates Jurassic felsic source rocks. Another possible source was the Alisitos volcanic arc, exposed along the western margin of the Baja California Peninsula. Of regional significance is the great similarity between the El Chanate Group and the McCoy Mountains Formation of southeastern California and southwestern Arizona. Both are Cretaceous, were deposited in continental environments, and have similar zircon-age patterns. Also, both exhibit intense deformation and locally display penetrative foliation. These features strongly suggest that both units underwent

  7. Tectonic and climatic significance of a late Eocene low-relief, high-level geomorphic surface, Colorado

    NASA Technical Reports Server (NTRS)

    Gregory, Kathryn M.; Chase, Clement G

    1994-01-01

    New paleobotanical data suggest that in the late Eocene the erosion surface which capped the Front Range, Colorado was 2.2-2.3 km in elevation, which is similar to the 2.5-km present elevation of surface remnants. This estimated elevation casts doubt on the conventional belief that the low-relief geomorphic surface was formed by lateral planation of streams to a base level not much higher than sea level and that the present deeply incised canyons must represent Neogene uplift of Colorado. Description of the surface, calculations of sediment volume, and isostatic balance and fluvial landsculpting models demonstrate that while the high elevation of the erosion surface was due to tectonic forces, its smoothness was mostly a result of climatic factors. A sediment balance calculated for the Front Range suggests that from 2 to 4 km of material were eroded by the late Eocene, consistent with fission track ages. This amount of erosion would remove a significant portionof the 7 km of Laramide upper crustal thickening. Isostatic modeling implies that the 2.2-3.3 km elevation was most likely created by lower crustal thickening during the Laramide. A numerical model of fluvial erosion and deposition suggests a way that a late Eocene surface could have formed at this high elevation without incision. A humid climate with a preponderance of small storm events will diffusively smooth topography and is a possible mechanism for formation oflow-relief, high-level surfaces. Paleoclimate models suggest a lack of large strom events in the late Eocene because of cool sea surface temperatures in the equatorial region. Return to a drier but stormier climate post-Eocene could have caused the incision of the surface by young canyons. By this interpretation, regional erosion surfaces may represent regional climatic rather than tectonic conditions.

  8. Geochonology and Tectonic Significance of post-collisional porphyry in Qulong area, southeast segment of the Gangdese belt, Tibet, China

    NASA Astrophysics Data System (ADS)

    Liu, D.; Zeren, Z.; Du, C.; Feng, L.; Nima, C.; Zhang, L.

    2012-12-01

    With the collision of Indian plate and Eura-Asian plate, there developed complicated tectono-magmanism during Meso-Cenozoic in Gangdese belt, Xizang Tibet. Therefore, it resulted that plentiful tectonism and post-collision high-K calc-alkaline magmatism related to mineralization distrubted from east to west in the belt. And this is quite significant for us to do some rearch on large-scale metallogenetics, uplifting epoch and EW-striking extension during the post-collision in Xizang-Qinghai Plateau. Zircon samples from Cangrila Granodiorite-porphyry in Qulong area, Southeast of Gangdese porphyry copper belt, Xiangbeishan diorite-porphyrite and from Jiama Granite-porphyry give LA-ICPMS U-Pb ages of 16.3Ma, 14. 4Ma, and 15.4Ma, respectively, and all these ages represent the porphyries' forming ages. From barren Xiangbeishan diorite-porphyrite through intermediately mineralized Jiama Granite-porphyry to stongly mineralized Cangrila Granodiorite-porphyry, the LA-ICPMS U-Pb ages of zircon become younger and younger. According to the regional data and geochemical characteristics, these porphyries were mainly derived directly from the thickened mafic lower-crust formed in south Tibet during collision and epeirogeny. During post-collisional extension stage, for inter-earth thermal flowing, SN-striking normal faulting systems across the Tibetan orogen caused rapid rising and localization of porphyry magmas and adequately separating of massive ore-bearing fluids from the magmatic hydrothermal systems. All these data indicate that Gandese belt has experienced from post-collisional extrusion changed into intra-plate extension since Miocene. During Miocene, Gangdese belt undergone violent intraplate extension, post-collisional porphyry intrusion and paroxysmal massive mineralization of porphyry-type, and all these was controlled by deep dynamics. Key Words: Qulong area; Gangdese tectonic belt; Tibet;Zircon La-ICP-MS U-Pb dating; intra-plate extension; Image Information For CL

  9. Tectonic and climatic significance of a late Eocene low-relief, high-level geomorphic surface, Colorado

    NASA Technical Reports Server (NTRS)

    Gregory, Kathryn M.; Chase, Clement G

    1994-01-01

    New paleobotanical data suggest that in the late Eocene the erosion surface which capped the Front Range, Colorado was 2.2-2.3 km in elevation, which is similar to the 2.5-km present elevation of surface remnants. This estimated elevation casts doubt on the conventional belief that the low-relief geomorphic surface was formed by lateral planation of streams to a base level not much higher than sea level and that the present deeply incised canyons must represent Neogene uplift of Colorado. Description of the surface, calculations of sediment volume, and isostatic balance and fluvial landsculpting models demonstrate that while the high elevation of the erosion surface was due to tectonic forces, its smoothness was mostly a result of climatic factors. A sediment balance calculated for the Front Range suggests that from 2 to 4 km of material were eroded by the late Eocene, consistent with fission track ages. This amount of erosion would remove a significant portionof the 7 km of Laramide upper crustal thickening. Isostatic modeling implies that the 2.2-3.3 km elevation was most likely created by lower crustal thickening during the Laramide. A numerical model of fluvial erosion and deposition suggests a way that a late Eocene surface could have formed at this high elevation without incision. A humid climate with a preponderance of small storm events will diffusively smooth topography and is a possible mechanism for formation oflow-relief, high-level surfaces. Paleoclimate models suggest a lack of large strom events in the late Eocene because of cool sea surface temperatures in the equatorial region. Return to a drier but stormier climate post-Eocene could have caused the incision of the surface by young canyons. By this interpretation, regional erosion surfaces may represent regional climatic rather than tectonic conditions.

  10. Spatial variations in isostatic compensation mechanisms of the Ninetyeast Ridge and their tectonic significance

    NASA Astrophysics Data System (ADS)

    Sreejith, K. M.; Krishna, K. S.

    2013-10-01

    Ninetyeast Ridge (NER), one of the longest linear volcanic features on the Earth, offers an excellent opportunity of understanding the isostatic response to the interactions of mantle plume with the migrating mid-ocean ridge. Bathymetry, geoid, and gravity (shipborne and satellite) data along 72 closely spaced transects and 17 overlapping grids on the NER are analyzed and modeled to determine the effective elastic thickness (Te) beneath the entire ridge. The results of 2-D and 3-D flexural modeling of the NER show large spatial variations in Te values ranging from 4 to 35 km, suggesting that the ridge was compensated along its length by different isostatic mechanisms. The southern (south of 22°S latitude) and northern (north of 2°N latitude) parts of the NER have Te values of >10 and >23 km, respectively, revealing that the southern part was emplaced on a lithosphere of intermediate strength possibly on flank of the Indian plate, whereas the northern part was emplaced in an intraplate setting. In contrast, in the central part of the NER (between latitudes 22°S and 2°N), highly variable Te values (4-22 km) are estimated. The scattered Te values in the central NER suggest that this part may have evolved due to the occurrence of frequent ridge jumps caused by the interaction of Kerguelen hot spot with rapid northward migration of the Wharton spreading ridge. Residual Mantle Bouguer Anomaly (RMBA) map of the NER and adjacent basins reveals that the entire length of the NER is associated with a significant negative anomaly up to 200 mGal, indicating the presence of thickened crust or less dense mantle beneath the ridge. 3-D crustal thickness map of the NER, generated by inversion of the RMBA data, shows a thick crust ranging from 15 to 19 km. The present study clearly shows that NER possesses a highly segmented isostatic pattern with the occurrence of subcrustal underplating or subsurface loading.

  11. CHARACTER AND REGIONAL SIGNIFICANCE OF GREAT FALLS TECTONIC ZONE, EAST-CENTRAL IDAHO AND WEST-CENTRAL MONTANA.

    USGS Publications Warehouse

    O'Neill, J. Michael; Lopez, David A.

    1985-01-01

    The Great Falls tectonic zone, here named, is a belt of diverse northeast-trending geologic features that can be traced from the Idaho batholith in the Cordilleran miogeocline, across thrust-belt structures and basement rocks of west-central and southwestern Montana, through cratonic rocks of central Montana, and into southwestern-most Saskatchewan, Canada. Geologic mapping in east-central Idaho and west-central Montana has outlined a continuous zone of high-angle faults and shear zones. Recurrent fault movement in this zone and strong structural control over igneous intrusion suggest a fundamental tectonic feature that has influenced the tectonic development of the Idaho-Montana area from a least middle Proterozoic time to the present. Refs.

  12. Significance of serum antibody test for toxocariasis in healthy healthcare examinees with eosinophilia in Seoul and Gyeongsangnam-do, Korea.

    PubMed

    Kim, Hong Seok; Jin, Yan; Choi, Min-Ho; Kim, Jae-Hwan; Lee, Young Ha; Yoon, Cheong Ha; Hwang, Eui-Hyuk; Kang, Hun; Ahn, Sang-Yong; Kim, Gi Jin; Hong, Sung-Tae

    2014-12-01

    There have been numerous reports on the relationship between eosinophilia and toxocariasis. The present study investigated seropositive rates of toxocariasis among healthy people with or without eosinophilia in urban and rural areas, and assessed risk factors for positive antibody test. A total of 610 healthy people, who visited health check-up (Medicheck®, Korea Association of Health Promotion), 310 from Seoul and 300 from Gyeongsangnam-do, were subjected for this study. Their serum samples were tested by ELISA with the crude antigen of Toxocara canis larvae. Cross-reactions with other tissue invading helminth antigens were also investigated. Total antibody positive rate of toxocariasis was 8.7% of the 610 subjects. When the subjects were grouped into 3 by their eosinophil counts, the antibody positive rates significantly differed by the groups; 5.9% (18/306) in the group<350/µL, 10.0% (11/110) in the group 350-500/µL, and 12.4% (24/194) in the group>500/µL (P=0.028). A total of 22 serum samples cross-reacted with other tissue-invading helminth antigens. A questionnaire analysis recognized drinking alcohol and smoking as significant risk factors of toxocariasis. In conclusion, toxocariasis antibody positive rate is correlated with eosinophil counts. It is recommended that healthy subjects with eosinophilia by routine health examination and risk factors undergo Toxocara serology by multiantigen ELISA to investigate etiology.

  13. Petrogenesis and tectonic significance of the Eocene adakite-like rocks in western Yunnan, southeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Ding, Huixia; Hou, Qingye; Zhang, Zeming

    2016-02-01

    Eocene magmatic rocks are widespread in western Yunnan, southeastern Tibetan Plateau. However, their petrogenesis and tectonic significance remain controversial. In this paper, we report geochemical and geochronological data of adakite-like rocks from the eastern part of western Yunnan. Zircon U-Pb dating reveals that they were emplaced at ca. 35 Ma. A geochemical study shows that these rocks have high SiO2 (68.97-72.44 wt.%), K2O (4.35-5.87 wt.%) and low MgO (0.61-1.16 wt.%), Y (6.65-12.6 ppm) and Yb (0.58-1.02 ppm) contents as well as high Sr/Y (74-228) and La/Yb (59-131) values, belonging to high-K calc-alkaline to shoshonitic adakite-like rocks. These rocks have high (87Sr/86Sr)i (0.70623-0.70653), low εNd(t) (- 4.5 to - 7.5) and slightly low radiogenic Pb isotopic compositions with (206Pb/204Pb)i = 18.042-18.179. Zircons of these rocks show εHf(t) values ranging from - 6.3 to + 1.2 and model ages (TDM2) of 1513-1035 Ma. The geochemical characteristics indicate that the Eocene adakite-like rocks from the eastern part of western Yunnan were derived from the partial melting of Neoproterozoic mafic rocks underplated in the lower crust of the western margin of the Yangtze Plate with input of mantle-derived potassic-ultrapotassic melt. Integration of published geochemical data clearly shows that zircon εHf(t) and whole-rock εNd(t) values of Eocene adakite-like rocks from the whole western Yunnan exhibit a trend of westward increase. We infer that the adakite-like rocks from the western part of western Yunnan were derived from the partial melting of late Paleozoic-Mesozoic mafic rocks formed as the lower crust of a continental magmatic arc during eastward subduction of the Paleo-Tethyan Ocean, and the Eocene magmatic rocks in western Yunnan were generated during the removal of thickened continental lithosphere triggered by the India and Asia collision.

  14. Distinct deformational history of two contrasting tectonic domains in the Chinese Altai: Their significance in understanding accretionary orogenic process

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Sun, Min; Schulmann, Karel; Zhao, Guochun; Wu, Qihang; Jiang, Yingde; Guy, Alexandra; Wang, Yuejun

    2015-04-01

    The Chinese Altai, a key component of the western Central Asian Orogenic Belt, is considered to be formed through multiple accretions of different terranes. However, the deformational histories of each terrane (tectonic domain), i.e. structural records before and after the accretion, are rarely studied, which has hindered our understanding of the accretionary processes. To fill the gap, a systematic macro- and microscopic structural analysis was carried out on two contrasting litho-tectonic units, i.e. the early Paleozoic low-grade Alegedayi Ophiolitic Complex (AOC) juxtaposed to the high grade Tarlang Granitic Massif (TGM). Selected rock samples were analyzed using zircon U-Pb isotopic dating to constrain the timing of polyphase deformation. Our structural and geochronological data suggest that the two litho-tectonic units were initially detached and located in different crustal levels and experienced distinct phases of deformation under contrasting P-T conditions. They were mutually accreted with each other in the early Devonian and jointly underwent a WNW-ESE-directed shortening deformational event (D1) at ˜390 Ma. The change of tectonic regime was further enhanced by a subsequent NNE-SSW-directed shortening deformation (D2) after ˜ 380 Ma. The shortening process ended before the crustal-scale sinistral strike-slip shearing deformation along the Erqis fault zone at 290 - 240 Ma. Results of this study provide solid field-based evidence for a model that the Chinese Altai initially underwent a nearly E-W-oriented subduction-accretional event in the middle Paleozoic, before it was reoriented to a nearly N-S-oriented convergence.

  15. Metasomatic Evolution in Tectonically Mixed Zones (Mélange) and Significance for Geochemical Evolution of the Slab-Mantle Interface

    NASA Astrophysics Data System (ADS)

    Bebout, G. E.; King, R. L.

    2012-12-01

    Fluid flow focused in highly deformed zones (shear zones), and the physical juxtaposition of chemically disparate rocks (via mechanical mixing) in such zones, can lead to extensive metasomatism, including volume strain, and result in rocks with hybridized compositions little resembling the compositions of the incorporated rock types [1-5]. In the Catalina Schist (California), lawsonite-albite, lawsonite-blueschist, and amphibolite-facies units contain shear zones at scales of meters to kilometers, each containing "blocks" (with more spherical or more tabular dimensions) co-facial in grade with the "matrix" surrounding these blocks [1-3]. Oxygen isotope data for these "mélange" units, and adjacent more "coherent" expanses, indicate enhanced fluid flow in the more strongly deforming mélange zones while fluid flow in coherent domains was dominantly fracture-controlled and episodic. The amphibolite-facies mélange unit shows evidence for km-scale equilibration of varying mineral assemblages with H2O-rich fluids with uniform O and H isotope compositions consistent with a lower-grade metasedimentary source. This unit is believed to have formed largely by mechanical mixing of mafic and ultramafic compositions, partly because of the scarcity of sedimentary blocks. However, the mélange matrix in this unit preserves a number of sedimentary chemical/isotopic characteristics (e.g., Pb isotope compositions [3]) that could reflect the incorporation of sedimentary rocks, with or without fluid-related fractionation, and possibly fluid-mediated additions. Tectonically mixed zones such as these, if volumetrically significant at the slab-mantle interface, could exert disproportionate control on the compositions of hydrous fluids or silicate melts emanating from subducting slabs and entering the forearc to backarc mantle wedge, including those contributing to arc magmatism [1-5]. Geochemical studies of arc lavas should consider the possibility that the "fluids" contributed from

  16. The reinterpretation of Leone Lake sediments as a pyroclastic surge deposit and its tectonic significance. [volcanics in Cascade Range of Oregon

    NASA Technical Reports Server (NTRS)

    Mcdonough, W. F.; Waibel, A. F.; Gannett, M. W.

    1984-01-01

    The Leone Lake sediments, previously interpreted as being of fluvial and lacustrine origin, are reinterpreted as subaerial pyroclastic surge and palagonite tuff cone deposits. This conclusion is based on bedforms, particle morphology, the primary mineral assemblage, and the nature and mineralogy of the alteration. The principal characteristics of the pyroclastic surge units and palagonite tuffs are examined, and the tectonic significance of the reinterpretation is briefly discussed.

  17. Tectonic significance of large-scale chaotic deposits in a Cretaceous fore-arc basin: Valle Formation, Cedros Island (Mexico)

    SciTech Connect

    Smith, D.P.; Busby-Spera, C.J. )

    1990-05-01

    A mappable, deep-marine slide deposit (olistostrome) within medial-Cretaceous fore-arc basin strata (Valle Formation), located on Cedros Island, Baja California Norte, records the initiation of intrabasinal faulting. Studies of both modern and ancient olistostromes show that olistostromes can form in all physiographic provinces (including shelf and abyssal plain) and tectonic settings of the marine environment. A variety of triggering mechanisms have been suggested for olistostromes, including tectonism, sea level changes, diapirism, rapid sedimentation that overloads steep slopes, migration of gas hydrates, or combinations of the above. The olistostrome in the Valle Formation ranges in thickness from 0 to at least 180 m, and extends areally for at least 34 km{sup 2}. It can be divided into two parts. The basal 30-40 m contains large (up to 8 m) angular blocks (allolistoliths) derived from the Jurassic substrate. The allolistoliths decrease in abundance upsection, whereas internally coherent intraformational slide blocks (endolistoliths), which reach tens of meters in width, increase. Beds composing the endolistoliths are alternating mudstone and sandstone turbidites that were deposited on a tectonically stable basin plain or rise setting before catastrophic failure of the sedimentary pile produced the olistostrome. Intrabasinal faulting is invoked as a cause of the sediment failure because of the presence of allolistoliths, which must have been shed into the basin from uplifted( ) basin floor scarps. Allolistoliths occur sporadically throughout at least 400 m of coarse-clastic sediment gravity-flow deposits that cap the olistostrome, suggesting that intrabasinal faulting continued to affect the basin long after the olistrostrome formed.

  18. Tectonic and flexural significance of Middle Devonian graben-fill sequence in new Albany shale, central Kentucky

    SciTech Connect

    Barnett, S.F.; Ettensohn, F.R.; Mellon, C. )

    1989-08-01

    The third tectonic phase of the Acadian orogeny began in the late Middle Devonian, and the sedimentary record of that event is largely restricted to the deeper, more proximal portions of the Appalachian foreland and Illinois intercratonic basins. Much of the intervening area, on and near the Cincinnati arch, was uplifted and subjected to erosion by movement on the peripheral bulge accompanying the initiation of the third tectonic phase. However, bulge movement also reactivated basement fault systems in Kentucky and created a series of grabens that were filled with eroded sediments and debris flows from adjacent horsts. Although rarely preserved, a buried Devonian graben along Carpenter Fork in Boyle County, central Kentucky, reveals such a sequence. The graben is bounded by upthrown blocks of Middle Devonian Boyle Dolomite, which also floors the graben. Within the graben a black-shale unit, apparently absent elsewhere, conformably overlies the Boyle and grades upward into debris-flow deposits represented by the Duffin breccia facies of the New Albany Shale. The Duffin contains clasts of the shale, as well as of chert, silicified fossils, and fine to boulder-size dolostone clasts eroded from the Boyle high on the flanks of the graben. The underlying shale also exhibits evidence of penecontemporaneous soft-sediment deformation related to the debris-flow emplacement of Boyle residue in the graben and due to later loading by the Duffin.

  19. Tectonic significance of mantle sources for mafic synextensional dikes in metamorphic core complexes, southern Arizona and northern Sonora

    SciTech Connect

    Wright, J.E. ); Haxel, G.B. ); Simmons, A.M.

    1992-01-01

    Synextensional microdiorite and lamprophyre dikes in the metamorphic core complexes (MCCs) of southern Arizona represent magmatism unambiguously associated with middle Tertiary crustal extension. These 24--20 Ma dikes are shoshonitic and primitive. Petrographic and geochemical data and AFC modeling suggest absence of an essential crustal source component. Dikes from individual MCCs have closely similar sr and Pb isotopic compositions that do not correlate with degree of fractionation, indicating little or no crustal assimilation. Minimal crustal interaction is consistent with emplacement of the dikes in a strongly extensional tectonic regime. Samples from the two MCC belts differ isotopically and chemically. Isotopic and trace element data indicate a minimum of three mantle sources, two lithospheric and one asthenospheric. The predominant lithospheric source for dikes in the northern belt was LILE-depleted Proterozoic lithosphere (EM1-like), whereas in the southern belt it was LILE-enriched lithosphere (trending toward EM2) strongly influenced by Proterozoic to Tertiary subduction. The asthenospheric source was available under both MCC belts but more widely or frequently tapped beneath the more highly extended northern belt. The presence of an asthenospheric component in some of the MCC dikes is the only known exception to the observation that asthenosphere-derived Cenozoic basalts first appeared in Arizona ca Ma. By the later stages of middle Tertiary crustal extension, the subduction zone beneath Arizona evidently had fragmented or became inactive, so that it did not form a barrier to ascent of asthenosphere-derived magmas. Continued study will evaluate the belief that these data support tectonic models for middle tertiary crustal extension in which the asthenospheric mantle is active rather than passive.

  20. Variation of palaeostress patterns along the Oriente transform wrench corridor, Cuba: significance for Neogene Quaternary tectonics of the Caribbean realm

    NASA Astrophysics Data System (ADS)

    Rojas-Agramonte, Y.; Neubauer, F.; Handler, R.; Garcia-Delgado, D. E.; Friedl, G.; Delgado-Damas, R.

    2005-02-01

    In this study, we address the late Miocene to Recent tectonic evolution of the North Caribbean (Oriente) Transform Wrench Corridor in the southern Sierra Maestra mountain range, SE Cuba. The region has been affected by historical earthquakes and shows many features of brittle deformation in late Miocene to Pleistocene reef and other shallow water deposits as well as in pre-Neogene, late Cretaceous to Eocene basement rocks. These late Miocene to Quaternary rocks are faulted, fractured, and contain calcite- and karst-filled extension gashes. Type and orientation of the principal normal palaeostress vary along strike in accordance with observations of large-scale submarine structures at the south-eastern Cuban margin. Initial N-S extension is correlated with a transtensional regime associated with the fault, later reactivated by sinistral and/or dextral shear, mainly along E-W-oriented strike-slip faults. Sinistral shear predominated and recorded similar kinematics as historical earthquakes in the Santiago region. We correlate palaeostress changes with the kinematic evolution along the boundary between the North American and Caribbean plates. Three different tectonic regimes were distinguished for the Oriente transform wrench corridor (OTWC): compression from late Eocene-Oligocene, transtension from late Oligocene to Miocene (?) (D 1), and transpression from Pliocene to Present (D 2-D 4), when this fault became a transform system. Furthermore, present-day structures vary along strike of the Oriente transform wrench corridor (OTWC) on the south-eastern Cuban coast, with dominantly transpressional/compressional and strike-slip structures in the east and transtension in the west. The focal mechanisms of historical earthquakes are in agreement with the dominant ENE-WSW transpressional structures found on land.

  1. Two contrasting metamorphosed ultramafic-mafic complexes from greenstone belts, the northern Kaapvaal Craton and their significance in Archaen tectonics

    NASA Technical Reports Server (NTRS)

    Smit, C. A.; Vearncombe, J. R.

    1986-01-01

    The character of Archaean ultramafic-mafic complexes can, given their prominance in greenstone belts, provide critical clues to help deduce the tectonic setting of these belts. Here are described two contrasting, metamorphosed, ultramafic-mafic complexes, the first a partially serpentinized dunitic body with associated chromite from Lemoenfontein, one of several peridotitic bodies occurring as discrete lenses and pods in granulite facies gneisses of the northern Kaapvaal craton. The second, the Rooiwater complex is a major layered igneous body, now metamorphosed in the amphibolite facies, but without pervasive deformation, which crops out in the northern Murchison greenstone belt. The Lemoenfontein chromites and associated ultramafic rocks are lithologically and chemically similar to their Phanerozoic equivalents of ophiolitic origin, interpreted as obducted oceanic crust. The Lemoenfontein complex is a remnant of Archaean oceanic material. In contrast, the Rooiwater complex is, despite the lack of exposed intrusive contacts, similar to layered igneous complexes such as Ushushwana or Bushveld. These complexes are intrusive in continental environments. It is concluded that contrasting ultramafic-mafic complexes represent a heterogeneity in greenstone belts with either oceanic or continental environments involved.

  2. Tectonic activity as a significant source of crustal tetrafluoromethane emissions to the atmosphere: Observations in groundwaters along the San Andreas Fault

    NASA Astrophysics Data System (ADS)

    Deeds, Daniel A.; Kulongoski, Justin T.; Mühle, Jens; Weiss, Ray F.

    2015-02-01

    Tetrafluoromethane (CF4) concentrations were measured in 14 groundwater samples from the Cuyama Valley, Mil Potrero and Cuddy Valley aquifers along the Big Bend section of the San Andreas Fault System (SAFS) in California to assess whether tectonic activity in this region is a significant source of crustal CF4 to the atmosphere. Dissolved CF4 concentrations in all groundwater samples but one were elevated with respect to estimated recharge concentrations including entrainment of excess air during recharge (Cre; ∼30 fmol kg-1 H2O), indicating subsurface addition of CF4 to these groundwaters. Groundwaters in the Cuyama Valley contain small CF4 excesses (0.1-9 times Cre), which may be attributed to an in situ release from weathering and a minor addition of deep crustal CF4 introduced to the shallow groundwater through nearby faults. CF4 excesses in groundwaters within 200 m of the SAFS are larger (10-980 times Cre) and indicate the presence of a deep crustal flux of CF4 that is likely associated with the physical alteration of silicate minerals in the shear zone of the SAFS. Extrapolating CF4 flux rates observed in this study to the full extent of the SAFS (1300 km × 20-100 km) suggests that the SAFS potentially emits (0.3- 1) ×10-1 kg CF4 yr-1 to the Earth's surface. For comparison, the chemical weathering of ∼ 7.5 ×104km2 of granitic rock in California is estimated to release (0.019- 3.2) ×10-1 kg CF4 yr-1. Tectonic activity is likely an important, and potentially the dominant, driver of natural emissions of CF4 to the atmosphere. Variations in preindustrial atmospheric CF4 as observed in paleo-archives such as ice cores may therefore represent changes in both continental weathering and tectonic activity, including changes driven by variations in continental ice cover during glacial-interglacial transitions.

  3. The tectonic significance of pre-Scandian 40Ar/39Ar phengite cooling ages in the Caledonides of western Norway

    USGS Publications Warehouse

    Andersen, T.B.; Berry, H.N.; Lux, D.R.; Andresen, A.

    1998-01-01

    Ordovician (Caradoc) time. The data also suggest that the Caledonian margin of Baltica may have experienced a more protracted tectonism during the Caledonian cycle than previously models focusing on Early Caledonian and Tremadoc (or older) ophiolite obduction and the Scandian continental collision between Baltica and Laurentia.

  4. Geochronology and geochemistry constraints of the Early Cretaceous Taibudai porphyry Cu deposit, northeast China, and its tectonic significance

    NASA Astrophysics Data System (ADS)

    Zhou, Zhen-Hua; Mao, Jing-Wen; Wu, Xin-Li; Ouyang, Hen-Gen

    2015-05-01

    The southern Great Xing'an Range (SGXR), located in the southeastern part of Inner Mongolia, China, shows intense Mesozoic tectono-magmatic activity and hosts economically important polymetallic (Cu-Pb-Zn-Sn-Fe-Ag-Au-Mo) mineralization. Here, we present new zircon U-Pb ages, whole-rock geochemical data, Nd-Sr-Hf isotopic data and Re-Os ages for the Taibudai deposit in the SGXR. The Taibudai granitoids show high SiO2 (70.62-72.13 wt.%) and alkali (Na2O + K2O = 7.04-8.60 wt.%) concentrations, low MgO (0.89-1.37 wt.%) and Al2O3 (∼14 wt.%), ASI ratios <1.1 (0.94-0.97), LILEs (e.g., Rb) enriched, HFSEs (e.g., Nb, Ta, Ti, and P) depleted, and have low Sr and Yb concentrations, classifying these rocks as fractionated I-type granites. The Taibudai granitoids have negative εNd (t) values ranging from -2.2 to -1.6 and relatively low initial 87Sr/86Sr ratios from 0.70536 to 0.70581. In situ Hf isotopic analyses on zircons using LA-MC-ICP-MS show variable positive εHf (t) values ranging from +0.80 to +13.55, corresponding to relatively young two-stage Hf model ages from 801 to 942 Ma (excluding one spot). These mineralogical, geochemical, and isotopic features strongly suggest that the primary magmas of the Taibudai granitoids were derived mainly from the partial remelting of Neoproterozoic juvenile crustal material, with no remarkable modification through incorporation of continental or subduction-related material. Re-Os isotope analyses of molybdenite from the deposit yield an ore-forming age of 137.1 ± 1.4 Ma. Re contents range from 4.37 to 41.77 ppm, implying ore material components have a mixed crust-mantle origin. SHRIMP analysis of zircons show that the monzogranitic porphyry and biotite granite in the Taibudai deposit were formed at 137.0 ± 0.9 Ma and 138.3 ± 0.9 Ma, respectively, indicating a temporal link between granitic magmatism and Cu mineralization. This result, combined with the regional geology, tectonic evolution, and age data from the literature

  5. Geological, Geochemical Characteristics and Tectonic Significance of Mafic and Ultramafic Rocks in the Northeast Segment of Antalya Complex, SW Turkey

    NASA Astrophysics Data System (ADS)

    Elitok, O.

    2005-12-01

    The area of SW Turkey known as the Isparta Angle include autochthonous and allochthonous units (from west to east the Lycian nappes, Beydaglari-Karacahisar autochthonous, the Antalya Complex, Anamas-Akseki autochthonous, and the Beysehir-Hoyran nappes). Emplacement of the nappes during Neotectonic evolution of Eastern Mediterranean region resulted in the formation of the Isparta Angle which has played an important role in tectonic evolution of Turkey and Eastern Mediterranean region. The study area is located in the northeast segment of Antalya Complex and covers an area of approximately 300 km2. Mainly carbonate rock unites constitute the autochthonous basement and overlain tectonicaly by the Obektas formation in olistostromal melange character, Kizildag Peridotite with ophiolitic melange and ophiolite-related metamorphic rocks, Pazarkoy group, and Dulup limestones. Pazarkoy group (Upper Triassic-Lower Cretaceous) include slope, basinal sedimantery rocks formed within passive margin environment, volcanic rocks characterized by different tectonomagmatic environments and serpentinites. Volcanic rocks are observed mainly as massive or pillow lavas at different locations in Pazarkoy group (at Akpinar Tepe, Havutlu, Ayvalipinar). The volcanics outcropping in the vicinity of Akpinar Tepe in alkaline basalt to trachyandesite composition and Ayvalipinar in alkaline basalt composition display nearly OIB-like pattern on the N-MORB normalized spider diagram with slightly negative Nb anomaly reflecting subduction zone affinity. But, on the tectonomagmatic discrimination diagrams (Zr/Y vs. Zr, V vs. Ti/1000), these volcanics plot within WPB field. The volcanics exposed around Havutlu, in Obektas formation and in ophiolitic melange have subalkaline basalt composition and on the primitive-mantle normalized spider diagram they show parallel pattern in HFSE with negative Nb-Ta anomaly. On the Chondrite-normalized REE pattern, volcanics taken from Havutlu display slightly

  6. Tectonic activity as a significant source of crustal tetrafluoromethane emissions to the atmosphere: observations in groundwaters along the San Andreas Fault

    USGS Publications Warehouse

    Deeds, Daniel A.; Kulongoski, Justin T.; Muhle, Jens; Weiss, Ray F.

    2015-01-01

    Tetrafluoromethane (CF4) concentrations were measured in 14 groundwater samples from the Cuyama Valley, Mil Potrero and Cuddy Valley aquifers along the Big Bend section of the San Andreas Fault System (SAFS) in California to assess whether tectonic activity in this region is a significant source of crustal CF4 to the atmosphere. Dissolved CF4 concentrations in all groundwater samples but one were elevated with respect to estimated recharge concentrations including entrainment of excess air during recharge (CreCre; ∼30 fmol kg−1 H2O), indicating subsurface addition of CF4 to these groundwaters. Groundwaters in the Cuyama Valley contain small CF4 excesses (0.1–9 times CreCre), which may be attributed to an in situ release from weathering and a minor addition of deep crustal CF4 introduced to the shallow groundwater through nearby faults. CF4 excesses in groundwaters within 200 m of the SAFS are larger (10–980 times CreCre) and indicate the presence of a deep crustal flux of CF4 that is likely associated with the physical alteration of silicate minerals in the shear zone of the SAFS. Extrapolating CF4 flux rates observed in this study to the full extent of the SAFS (1300 km × 20–100 km) suggests that the SAFS potentially emits (0.3–1)×10−1 kg(0.3–1)×10−1 kg CF4 yr−1 to the Earth's surface. For comparison, the chemical weathering of ∼7.5×104 km2∼7.5×104 km2 of granitic rock in California is estimated to release (0.019–3.2)×10−1 kg(0.019–3.2)×10−1 kg CF4 yr−1. Tectonic activity is likely an important, and potentially the dominant, driver of natural emissions of CF4 to the atmosphere. Variations in preindustrial atmospheric CF4 as observed in paleo-archives such as ice cores may therefore represent changes in both continental weathering and tectonic activity, including changes driven by variations in continental ice cover during glacial–interglacial transitions.

  7. Fracture mapping of lineaments and recognizing their tectonic significance using SPOT-5 satellite data: A case study from the Bajestan area, Lut Block, east of Iran

    NASA Astrophysics Data System (ADS)

    Ahmadirouhani, Reyhaneh; Rahimi, Behnam; Karimpour, Mohammad Hassan; Malekzadeh Shafaroudi, Azadeh; Afshar Najafi, Sadegh; Pour, Amin Beiranvand

    2017-10-01

    Syste'm Pour l'Observation de la Terre (SPOT) remote sensing satellite data have useful characteristics for lineament extraction and enhancement related to the tectonic evaluation of a region. In this study, lineament features in the Bajestan area associated with the tectonic significance of the Lut Block (LB), east Iran were mapped and characterized using SPOT-5 satellite data. The structure of the Bajestan area is affected by the activity of deep strike-slip faults in the boundary of the LB. Structural elements such as faults and major joints were extracted, mapped, and analyzed by the implementation of high-Pass and standard kernels (Threshold and Sobel) filters to bands 1, 2 and 3 of SPOT-5 Level 2 A scene product of the Bajestan area. Lineament map was produced by assigning resultant filter images to red-green-blue (RGB) colour combinations of three main directions such as N-S, E-W and NE-SW. Results derived from image processing technique and statistical assessment indicate that two main orientations, including NW-SE with N-110 azimuth and NE-SW with N-40 azimuth, were dominated in the Bajestan area. The NW-SE trend has a high frequency in the study area. Based on the results of remote sensing lineament analysis and fieldwork, two dextral and sinistral strike-slip components were identified as main fault trends in the Bajestan region. Two dextral faults have acted as the cause of shear in the south and north of the Bajestan granitoid mass. Furthermore, the results indicate that the most of the lineaments in this area are extensional fractures corresponding to both the dykes emplacement and hydrothermal alteration zones. The application of SPOT-5 satellite data for structural analysis in a study region has great capability to provide very useful information of a vast area with low cost and time-consuming.

  8. Soft sediment deformation structures in a lacustrine sedimentary succession induced by volcano-tectonic activities: An example from the Cretaceous Beolgeumri Formation, Wido Volcanics, Korea

    NASA Astrophysics Data System (ADS)

    Ko, Kyoungtae; Kim, Sung Won; Lee, Hong-Jin; Hwang, In Gul; Kim, Bok Chul; Kee, Won-Seo; Kim, Young-Seog; Gihm, Yong Sik

    2017-08-01

    deposits. Thus, we infer that the earthquakes that caused the development of SSD structures in the study area were closely related to syndepositional magmatic activities, as is the case for modern tectonic earthquakes around active volcanoes.

  9. Tectonic significance of lithicwacke-polymictic conglomerate petrofacies association within Upper Cretaceous torchlight sandstone, Big Horn basin, Wyoming

    SciTech Connect

    Khandaker, N.I.; Vondra, C.F.

    1987-05-01

    The Torchlight Sandstone belonging to the Upper Cretaceous Frontier Formation in the Big Horn basin, Wyoming, shows a distinctive lithicwacke-polymictic conglomerate is composed of granule-cobble-sized clasts of quartzite, chert, andesite, and argillite, and phyllite. The survival of phyllite, argillite, and neovolcanic andesite clasts indicate that the detritus underwent very little subaerial transport before it was deposited along the proximal margin of the foreland basin. A petrologically heterogeneous upland source of high to moderate relief is indicated by the clast size and composition. Hydrodynamic structures, in conjunction with textural attributes, and compositional data indicate that detritus moved southeast from its source terrane and was deposited by a high-energy distributary complex. The lithicwacke petrofacies is dominated by higher chert and quartz content with a subordinate amount of labile components including paleovolcanic clasts and fine-grained matrix. The development of phyllosilicate matrix around quartz and chert grains preserved the primary porosity and permeability of the sandstone. Absence of any noticeable quartz overgrowth apparently contributed to the preservation of good reservoir quality in this petrofacies. Considering its (Torchlight Sandstone) close proximity to the thrust belt and to the locus of andesite volcanism in the northwest and west, it is suggested that the extrabasinal detritus within the foreland basin can provide significant clues as to the timing of the thrust events and volcanicity in the adjacent region. New perspectives for hydrocarbon exploration and regional correlation may be gained by employing this petrofacies association.

  10. Geology and tectonic significance of a Late Proterozoic anorogenic silicic supersuite, Laurentian Appalachians, Virginia and North Carolina

    SciTech Connect

    Tollo, R.P. . Dept. of Geology); Bartholomew, M.J. ); Rankin, D.W. )

    1994-03-01

    Magmatic activity associated with regional extension produced more than 20 granitoid plutons within the Laurentian Appalachians of Virginia and North Carolina. The plutons constitute a supersuite that spans on age range of at least 760--700 Ma. The supersuite, which includes granitoids of the Crossnore Complex and the Robertson River Igneous Suite, among others, is geochemically consanguineous with silicic volcanic rocks at Mt. Rogers (760 Ma) and Battle Mountain (700 ma) in virginia. Variable in size, typically elongate to dike-like in form, and ranging from monzogranite to alkali feldspar syneite, most plutons record a sequence of multiple intrusions that, in the large robertson River batholith, spanned at least 35 m.y. The plutons define a compositionally coherent, metaluminous to (relatively rare) mildly peralkaline supersuite that is characterized by high Zr, Nb, Ga, Y, REE (not Eu), Fe/Mg, and Ga/Al, relatively to well-documented I-, S-, and M-type granitoids. These compositional features and mineralogic characteristics including the abundance of largely hypersolvus feldspar assemblages, occurrence of Fe-rich ferromagnesian silicates, and the ubiquitous presence of fluorite and allanite indicate that the plutons collectively may be classified as A-subtype granitoids. The Appalachian supersuite represents a significant, long-lived, temporally episodic period of magmatism that ended with encratonic rifting but not the development of oceanic crust. Individual plutons evolved independently and were not restricted to the vicinity of proto-Iapetan embayments. Younger (580--560 Ma) granitoids of the New York promontory are chemically indistinguishable from the supersuite.

  11. Tectonic Geomorphology.

    ERIC Educational Resources Information Center

    Bull, William B.

    1984-01-01

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

  12. Tectonic Geomorphology.

    ERIC Educational Resources Information Center

    Bull, William B.

    1984-01-01

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

  13. Syndepositional tectonics recorded by soft-sediment deformation and liquefaction structures (continental Lower Permian sediments, Southern Alps, Northern Italy): Stratigraphic significance

    NASA Astrophysics Data System (ADS)

    Berra, F.; Felletti, F.

    2011-04-01

    The Lower Permian succession of the Central Southern Alps (Lombardy, Northern Italy) was deposited in fault-controlled continental basins, probably related to transtensional tectonics. We focussed our study on the stratigraphic record of the Lower Permian Orobic Basin, which consists of a 1000 m thick succession of prevailing continental clastics with intercalations of ignimbritic flows and tuffs (Pizzo del Diavolo Formation, PDV) resting on the underlying prevailing pyroclastic flows of the Cabianca Volcanite. The PDV consists of a lower part (composed of conglomerates passing laterally to sandstones and distally to silt and shales), a middle part (pelitic, with carbonates) and an upper part (alternating sandstone, silt and volcanic flows). Syndepositional tectonics during the deposition of the PDV is recorded by facies distribution, thickness changes and by the presence of deformation and liquefaction structures interpreted as seismites. Deformation is recorded by both ductile structures (ball-and-pillow, plastic intrusion, disturbed lamination, convolute stratification and slumps) and brittle structures (sand dykes and autoclastic breccias). Both the sedimentological features and the geodynamic setting of the depositional basin confidently support the interpretation of the described deformation features as related to seismic shocks. The most significant seismically-induced deformation is represented by a slumped horizon (about 4 m thick on average) which can be followed laterally for more than 5 km. The slumped bed consists of playa-lake deposits (alternating pelites and microbial carbonates, associated with mud cracks and vertebrate tracks). The lateral continuity and the evidence of deposition on a very low-angle surface along with the deformation/liquefaction of the sediments suggest that the slump was triggered by a high-magnitude earthquake. The stratigraphic distribution of the seismites allows us to identify time intervals of intense seismic activity

  14. Volcanism & Tectonism

    NASA Image and Video Library

    2011-07-19

    Just as on Earth, volcanism and tectonism are found together on Mars. In this image from NASA 2001 Mars Odyssey spacecraft the ridges and fractures of Claritas Fossae are affecting or perhaps hosting the volcanic flows of Solis Planum.

  15. Tectonic Collapse

    NASA Image and Video Library

    2011-03-16

    The collapse valleys in this portion of the floor of Bernard Crater were likely caused by the formation of Memnonia Fossae, a system of tectonic graben, that passes through the region. This image was captured by NASA Mars Odyssey.

  16. Enceladan Tectonics

    NASA Image and Video Library

    2010-02-23

    This mosaic shows extraordinary details of tectonic deformation in the fractured south polar region of Saturn moon Enceladus, where jets of water ice spray outward to form Saturn E ring. The images were captured by NASA Cassini spacecraft.

  17. [South] Korea.

    PubMed

    1987-04-01

    The Republic of Korea occupies approximately 38,000 square miles in the southern position of a mountaineous peninsula. It shares a land boundary with North Korea. With a population of more than 40 million people, South Korea has 1 of the highest population densities in the world. The language spoken is a Uralic language, closely akin to Japanese, Hungarian, Finnish, and Mongolian, and the traditional religions are Shamanism and Buddhism. Over the course of time, South Korea has been invaded and fought over by its neighbors. The US and the Soviet Union have never been able to reach a unification agreement for North and South Korea. The 3rd Republic era, begun in 1963, saw a time of rapid industrialization and a great deal of economic growth. The 5th Republic began with a new constitution and new elections brought about the election of a president to a 7-year term of office beginning in 1981. Economic growth has been remarkable over the last 25 years despite the fact that North Korea possesses most of the mineral and hydroelectric resources and the existing heavy industrial base built by the Japanese while South Korea has the limited agricultural resources and had, initially, a large unskilled labor pool. Serious industrial growth began in South Korea in the early 1960s and the GNP grew at an annual rate of 10% during the period 1963-78. Current GNP is now, at $2000, well beyond that of its neighbors to the north. The outlook for longterm growth is good; however, the military threat posed by North Korea and the absence of foreign economic assistance has resulted in Korea spending 1/3 of its budget on defense. South Korea is active in international affairs and in the UN. Economic realities have forced Korea to give economics priority in their foreign policy. There has been an on-again, off-again quality to dialogue between the 2 nations. However, the US is committed to maintaining peace on the Korean peninsula. In order to do so, they have supplied manpower and

  18. Intrusion of horizontal dikes: tectonic significance of Middle Proterozoic diabase sheets widespread in the upper crust of the southwestern United States

    USGS Publications Warehouse

    Howard, K.A.

    1991-01-01

    Initially horizontal sheet intrusions of Middle Proterozoic diabase are abundant in a region 650 by 300 km across in Arizona and California. The diabase forms discordant sheets in basement granite and gneiss and sills in overlying shelf sedimentary sequences. Massive granite is the most common basement host for the sheets, probably because it fractured more easily than foliated hosts during sheet emplacement. Steep feeder dikes are rare compared to the sheets. The diabase in many places is exposed in fault blocks that were tilted during Tertiary tectonic extension. Structure sections restored from the map patterns of upended blocks shows that the sheets were intruded at levels throughout the upper crust, therefore it is concluded that the crust was under tectonic compression or in an isotropic state of stress at the time of diabase intrusion about 1.1 Ga. -from Author

  19. Tree Tectonics

    NASA Astrophysics Data System (ADS)

    Vogt, Peter R.

    2004-09-01

    Nature often replicates her processes at different scales of space and time in differing media. Here a tree-trunk cross section I am preparing for a dendrochronological display at the Battle Creek Cypress Swamp Nature Sanctuary (Calvert County, Maryland) dried and cracked in a way that replicates practically all the planform features found along the Mid-Oceanic Ridge (see Figure 1). The left-lateral offset of saw marks, contrasting with the right-lateral ``rift'' offset, even illustrates the distinction between transcurrent (strike-slip) and transform faults, the latter only recognized as a geologic feature, by J. Tuzo Wilson, in 1965. However, wood cracking is but one of many examples of natural processes that replicate one or several elements of lithospheric plate tectonics. Many of these examples occur in everyday venues and thus make great teaching aids, ``teachable'' from primary school to university levels. Plate tectonics, the dominant process of Earth geology, also occurs in miniature on the surface of some lava lakes, and as ``ice plate tectonics'' on our frozen seas and lakes. Ice tectonics also happens at larger spatial and temporal scales on the Jovian moons Europa and perhaps Ganymede. Tabletop plate tectonics, in which a molten-paraffin ``asthenosphere'' is surfaced by a skin of congealing wax ``plates,'' first replicated Mid-Oceanic Ridge type seafloor spreading more than three decades ago. A seismologist (J. Brune, personal communication, 2004) discovered wax plate tectonics by casually and serendipitously pulling a stick across a container of molten wax his wife and daughters had used in making candles. Brune and his student D. Oldenburg followed up and mirabile dictu published the results in Science (178, 301-304).

  20. Collision tectonics

    SciTech Connect

    Coward, M.P.; Ries, A.C.

    1985-01-01

    The motions of lithospheric plates have produced most existing mountain ranges, but structures produced as a result of, and following the collision of continental plates need to be distinguished from those produced before by subduction. If subduction is normally only stopped when collision occurs, then most geologically ancient fold belts must be collisional, so it is essential to recognize and understand the effects of the collision process. This book consists of papers that review collision tectonics, covering tectonics, structure, geochemistry, paleomagnetism, metamorphism, and magmatism.

  1. Charon tectonics

    PubMed Central

    Beyer, Ross A.; Nimmo, Francis; McKinnon, William B.; Moore, Jeffrey M.; Binzel, Richard P.; Conrad, Jack W.; Cheng, Andy; Ennico, K.; Lauer, Tod R.; Olkin, C.B.; Robbins, Stuart; Schenk, Paul; Singer, Kelsi; Spencer, John R.; Stern, S. Alan; Weaver, H.A.; Young, L.A.; Zangari, Amanda M.

    2017-01-01

    New Horizons images of Pluto’s companion Charon show a variety of terrains that display extensional tectonic features, with relief surprising for this relatively small world. These features suggest a global extensional areal strain of order 1% early in Charon’s history. Such extension is consistent with the presence of an ancient global ocean, now frozen. PMID:28919640

  2. Charon tectonics

    NASA Astrophysics Data System (ADS)

    Beyer, Ross A.; Nimmo, Francis; McKinnon, William B.; Moore, Jeffrey M.; Binzel, Richard P.; Conrad, Jack W.; Cheng, Andy; Ennico, K.; Lauer, Tod R.; Olkin, C. B.; Robbins, Stuart; Schenk, Paul; Singer, Kelsi; Spencer, John R.; Stern, S. Alan; Weaver, H. A.; Young, L. A.; Zangari, Amanda M.

    2017-05-01

    New Horizons images of Pluto's companion Charon show a variety of terrains that display extensional tectonic features, with relief surprising for this relatively small world. These features suggest a global extensional areal strain of order 1% early in Charon's history. Such extension is consistent with the presence of an ancient global ocean, now frozen.

  3. Charon tectonics.

    PubMed

    Beyer, Ross A; Nimmo, Francis; McKinnon, William B; Moore, Jeffrey M; Binzel, Richard P; Conrad, Jack W; Cheng, Andy; Ennico, K; Lauer, Tod R; Olkin, C B; Robbins, Stuart; Schenk, Paul; Singer, Kelsi; Spencer, John R; Stern, S Alan; Weaver, H A; Young, L A; Zangari, Amanda M

    2017-05-01

    New Horizons images of Pluto's companion Charon show a variety of terrains that display extensional tectonic features, with relief surprising for this relatively small world. These features suggest a global extensional areal strain of order 1% early in Charon's history. Such extension is consistent with the presence of an ancient global ocean, now frozen.

  4. Active tectonics

    SciTech Connect

    Not Available

    1986-01-01

    This study is part of a series of Studies in Geophysics that have been undertaken for the Geophysics Research Forum by the Geophysics Study Committee. One purpose of each study is to provide assessments from the scientific community to aid policymakers in decisions on societal problems that involve geophysics. An important part of such assessments is an evaluation of the adequacy of current geophysical knowledge and the appropriateness of current research programs as a source of information required for those decisions. The study addresses our current scientific understanding of active tectonics --- particularly the patterns and rates of ongoing tectonic processes. Many of these processes cannot be described reasonably using the limited instrumental or historical records; however, most can be described adequately for practical purposes using the geologic record of the past 500,000 years. A program of fundamental research focusing especially on Quaternary tectonic geology and geomorphology, paleoseismology, neotectonics, and geodesy is recommended to better understand ongoing, active tectonic processes. This volume contains 16 papers. Individual papers are indexed separately on the Energy Database.

  5. The tectonic significance of K/Ar illite fine-fraction ages from the San Luis Formation (Eastern Sierras Pampeanas, Argentina)

    NASA Astrophysics Data System (ADS)

    Wemmer, Klaus; Steenken, André; Müller, Stefan; de Luchi, Mónica G. López; Siegesmund, Siegfried

    2011-04-01

    The Sierra de San Luis forms the southern tip of the Eastern Sierras Pampeanas in central Argentina. Two narrow belts of low-grade phyllites and quartz arenites, i.e. the San Luis Formation, have accommodated part of the strain-related differential exhumation of the medium- to high-grade metamorphic domains that constitute to the basement complex of the sierra. Eleven phyllite samples were subjected to the K/Ar fine-fraction dating technique. Results are interpreted in relation to the Kübler index of the illites, which indicate epimetamorphic conditions for the majority of the samples. Obtained ages between 330 and 290 Ma cover a period of compressional tectonics in the late Mississippian (Visean/Serpukhovian boundary) followed by the subsidence during the formation of the Paganzo Basin in the provinces of La Rioja and San Luis. These tectonic movements are coincident with the Toco orogeny in northern Chile and southern Bolivia. This suggests that the older K/Ar ages document the compressional stage and that younger ages record the cooling of the basement during the subsequent extensional uplift of the basement.

  6. [Significance of cross-cultural experience for young psychiatrists--learning from "The Joint Workshop for Psychiatric Residents of Korea and Japan"].

    PubMed

    kato, Takahiro

    2006-01-01

    Korea and Japan are geographically very close, and a variety of cultural exchanges have taken place in recorded history. However, Korea and Japan have been enriched by the influence of Western cultures along with modernization, and mutual exchanges between the two countries have thus decreased in numerous fields including mental health and psychiatry. Prof. Masahisa Nishizono and Prof. Byun-Kun Min, who are leaders in the field of psychiatry in both Japan and Korea, have established "The Joint Workshop for Psychiatric Residents of Korea and Japan", which has been held alternately in Fukuoka or Seoul every summer since 2000. This Joint Workshop provides young psychiatrists with real experiences and many opportunities to learn about transcultural psychiatry regarding both countries. The participants are able to obtain a better mutual understanding of psychiatric epidemiology, recent developments in biological psychiatry while also learning about different concepts regarding the stigma of mental disorders. All participants could also increase their knowledge about the traditional culture and social changes related to the field of psychiatry in both countries. The workshop has helped to build friendship and mutual cooperation between both nations. Contemporary societies are continually becoming more and more diversified and complicated. For young psychiatrists who have to treat patients with modern difficulties and various complicated problems, such cross-cultural experiences may be useful for establishing potentially new and effective treatments for such patients. Psychiatrists and mental health experts have tried to reduce of stigma and discrimination against people with mental disorders, but even today such stigma and discrimination continues to strongly exist. The author thinks that such cross-cultural experiences by the psychiatrists themselves may help to reduce such notions. The author would like to explore the role of cross-cultural experiences in the field of

  7. Sediment transport on macrotidal flats in Garolim Bay, west coast of Korea: significance of wind waves and asymmetry of tidal currents

    NASA Astrophysics Data System (ADS)

    Lee, Hee J.; Jo, Hyung R.; Chu, Yong S.; Bahk, Kyung S.

    2004-05-01

    A self-recording instrument, named Tidal Sediment Dynamics Observational System (TISDOS), was built to monitor transport characteristics of nearbed sediments on tidal flats. It was deployed on a tidal flat in the semi-enclosed Garolim Bay, west coast of Korea, over a 15-day period between 5 and 20 January 2002 to examine sediment-transport processes during winter seasons. The measurements involved brief durations of high waves allowing for observation of wave effects upon the sediment transport on the tidal flat. Time series of various hydrodynamic parameters (water depth, current velocities, wave height, suspended sediment concentration, and bed level) from point measurements show characteristic interrelationships between parameters on both temporal and spatial scales. The tidal flat is dominated by flooding currents up to 2 times stronger than ebb currents. The current speeds measured simultaneously at two stations along a cross-shore transect varied in harmony with water depth, reaching the maximum during spring tide that was steadily decreased onshore. The onshore decrease in current speed was compatible with a fining textural trend from sand on the lower flat to mud toward the upper flat. Both the maximum water depth and current speed during individual tidal cycles also show semi-diurnal asymmetry that was highlighted during spring tide. Waves were of critical importance in resuspending bed material and thus yielding higher suspended sediment concentrations. On the middle flat, the suspended sediment concentrations were highest, exceeding 400 mg/l at 0.5 m above the seabed during large waves (relative wave height, 0.33) under weakest neap currents. In this wavy climate, the suspended sediment concentration increased over time during ebb, in strong contrast with a gradual decrease through time after mid-flood peaks under tidal currents without waves. The daily vertical flux of suspended sediments trapped in a plastic bottle also indicates the significance of

  8. Petrology and tectonic significance of gabbros, tonalites, shoshonites, and anorthosites in a late Paleozoic arc-root complex in the Wrangellia Terrane, southern Alaska

    SciTech Connect

    Beard, J.S. ); Barker, F. )

    1989-11-01

    Plutonic rocks intrusive into the late Paleozoic Tetelna Formation of southern Alaska are the underpinnings of the late Paleozoic Skolai arc of the Wrangellia Terrane. There are four groups of intrusive rocks within the Skolai arc: (1) Gabbro-diorite plutons that contain gabbroic to anorthositic cumulates along with a differentiated series of gabbros and diorites of basaltic to andesitic composition; (2) Silicic intrusions including tonalite, granodiorite, and granite; (3) Monzonitic to syenitic plutonic rocks of the Ahtell complex and related dikes and sills; (4) Fault-bounded bytownite anorthosite of uncertain age and association. These anorthosites may be related to post-Skolai, Nikolai Greenstone magmatism. The silicic rocks yield discordant U-Pb zircon ages of 290-320 Ma (early to late Pennsylvanian). The monzonitic rocks of the Ahtell complex have shoshonitic chemistry. Similar shoshonitic rocks are widespread in both the Wrangellia terrane and the neighboring Alexander terrane and intrude the contact between the two. In modern oceanic arcs, shoshonitic rocks are typically associated with tectonic instability occurring during the initial stages of subduction or just prior to or during termination or flip of an established subduction zone. The nature of any tectonic instability which may have led to the cessation of subduction in the Skolai arc is unclear. Possibilities include collision of the arc with a ridge, an oceanic plateau, another arc, or a continental fragment. One possibility is that the shoshonitic magmatism marks the late Paleozoic amalgamation of Wrangellia and the Alexander terrane. The scarcity of arc rocks predating the shoshonites in the Alexander terrane supports this possibility, but structural corroboration is lacking.

  9. Late Miocene-Pliocene geomorphological evolution of the Xiaoshuizi peneplain in the Maxian Mountains and its tectonic significance for the northeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Jijun; Ma, Zhenhua; Li, Xiaomiao; Peng, Tingjiang; Guo, Benhong; Zhang, Jun; Song, Chunhui; Liu, Jia; Hui, Zhengchuang; Yu, Hao; Ye, Xiyan; Liu, Shanpin; Wang, Xiuxi

    2017-10-01

    As a remnant elevated peneplain, the Tangxian planation surface is widely distributed in North China and the Ordos Plateau. Further into the Tibetan Plateau (TP), the Main planation surface can also be traced across this, the highest plateau on the Earth's surface. What the relation is between these two planation surfaces and whether they represent the remnants of a unique planation surface remains open to question. As the intermediate region between the low-altitude North China and the high-altitude TP, the Maxian Mountains and such bilateral basins located in the northeastern TP margin retain a series of well-preserved geomorphic features such as planation surfaces, pediment surface, and the fluvial terraces of the Yellow River. When and how the Xiaoshuizi peneplain was formed are crucial questions to elucidate the geomorphic evolution of the northeastern TP and infer the tectonic history of the TP. Here we present two parallel red clay-loess drill cores from the uplifted Xiaoshuizi bedrock peneplain in the Maxian Mountains, which document both the upper formation age of the planation surface and the evolution of Asian aridification. Based on the integration of high-resolution magnetostratigraphy analysis and Pliocene mammal fossils, we demonstrate that the red clay-loess succession deposited on the Xiaoshuizi peneplain probably began to accumulate at 6.9 Ma, implying that the Xiaoshuizi peneplain had begun to form before this. These results support the hypothesis that the Xiaoshuizi planation surface is equivalent to Tangxian planation surface of North China and Main planation surface of the TP. Furthermore, the onset of red clay sequence may indicate that the Xiaoshuizi peneplain was ultimately destroyed by the intensive tectonic uplift of the northeastern TP before 6.9 Ma. Taking into account the synchronous Late Miocene red clay deposition between the Xiaoshuizi peneplain and central Chinese Loess Plateau (CLP), we propose that the onset of interior Asian

  10. Tectonic significance of the Dongqiao ophiolite in the north-central Tibetan plateau: Evidence from zircon dating, petrological, geochemical and Sr-Nd-Hf isotopic characterization

    NASA Astrophysics Data System (ADS)

    Liu, Tong; Zhai, Qing-guo; Wang, Jun; Bao, Pei-sheng; Qiangba, Zhaxi; Tang, Suo-han; Tang, Yue

    2016-02-01

    The Dongqiao ophiolite occurs in the central segment of the Bangong-Nujiang suture zone, in north-central Tibet, China. It is still debated on the tectonic setting of the Dongqiao ophiolite despite after more than 30 years' studies. The Dongqiao ophiolite has a complete section of a typical ophiolite, composed of harzburgite, dunite, layered and isotropic gabbros, pillow and massive basalts, as well as radiolarian chert. Whole-rock geochemical analyses show that harzburgite displays a broad U-shaped REE pattern and has a fore-arc affinity, whereas basalts show affinities of E-MORB, OIB and IAB. The basalts were probably formed in different tectonic settings, that is, mid-ocean ridge, oceanic island and island arc. The gabbros and basalts are characterized by positive εNd(t) (+1.6 to +6.7) and εHf(t) (+8.1 to +13.9) values. Zircon U-Pb dating yielded ages of 188 ± 1 Ma for the layered gabbro and 181 ± 1 Ma for the amphibole gabbro. The new ages and the published age data of the Dingqing and Dong Co ophiolites led us to conclude that the Bangong-Nujiang Ocean existed from the Late Triassic to Early Cretaceous. The new geochemical data also suggested that the Dongqiao ophiolite was a typical SSZ-type ophiolite formed in an initial fore-arc oceanic basin. Fore-arc ophiolites are probably widely distributed along the Bangong-Nujiang suture zone. If so, the Tethys Ocean of the Bangong-Nujiang area probably existed as a fore-arc oceanic basin during the Late Triassic to Early Jurassic.

  11. Timing, Structural Styles, and Tectonic Significance of Neogene Basin Inversion Across the South China Sea and Indonesian Back-Arc Region

    NASA Astrophysics Data System (ADS)

    Dorobek, S. L.; Olson, C. C.

    2005-12-01

    Basin inversion is a common phenomenon in many intracontinental extensional or transtensional settings that are subjected to later contractional deformation. Numerous examples of inverted Paleogene rift basins are found in the Indonesian back-arc region and southern and western parts of the South China Sea. Inversion was widespread across the broad region, mainly began in latest Oligocene-early Miocene time, and locally continues to the present day. Most basins were fully inverted in less than 15 Myr and inversion typically involved reactivation of preexisting extensional fault systems that formed during Paleogene rifting. We examined the tectonic styles and regional timing of basin inversion across this region in order to understand the tectonic and geodynamic reasons for the inversion. The timing of regional inversion and structural styles associated with inversion reflect roughly N-S to NNW-SSE oriented intraplate compressive stress, which suggests that incipient collision of Australian continental crust along the eastern Indonesian archipelago and `South Chinese/Vietnamese' crust along the Borneo/South Palawan margin were responsible for the widespread inversion. A fundamental change from uncoupled to coupled subduction along the Indonesian trench and Borneo/South Palawan margin, coincident with the incipient subduction of continental crust along these convergent margins during latest Oligocene-early Miocene time, may explain why intraplate compressive stress was transmitted across the Indonesian back-arc and southern South China Sea (Sunda Shelf) region. Prior to late Oligocene time, subduction was essentially uncoupled and Paleogene rift basins across the Indonesian backarc and Sunda Shelf region were thermally subsiding. The rheology of Sundaland and offshore Southeast Asian continental lithosphere also was especially conducive to widespread, nearly synchronous basin inversion during Neogene time, which likely reflects the low viscosity nature of the mantle

  12. Spiral tectonics

    NASA Astrophysics Data System (ADS)

    Hassan Asadiyan, Mohammad

    2014-05-01

    Spiral Tectonics (ST) is a new window to global tectonics introduced as alternative model for Plate Tectonics (PT). ST based upon Dahw(rolling) and Tahw(spreading) dynamics. Analogues to electric and magnetic components in the electromagnetic theory we could consider Dahw and Tahw as components of geodynamics, when one component increases the other decreases and vice versa. They are changed to each other during geological history. D-component represents continental crust and T-component represents oceanic crust. D and T are two arm of spiral-cell. T-arm 180 degree lags behind D-arm so named Retard-arm with respect to D or Forward-arm. It seems primary cell injected several billions years ago from Earth's center therefore the Earth's core was built up first then mantel and finally the crust was build up. Crust building initiate from Arabia (Mecca). As the universe extended gravitation wave swirled the earth fractaly along cycloid path from big to small scale. In global scale (order-0) ST collect continents in one side and abandoned Pacific Ocean in the other side. Recent researches also show two mantels upwelling in opposite side of the Earth: one under Africa (tectonic pose) and the other under Pacific Ocean (tectonic tail). In higher order (order-1) ST build up Africa in one side and S.America in the other side therefore left Atlantic Ocean meandered in between. In order-n e.g. Khoor Musa and Bandar-Deylam bay are seen meandered easterly in the Iranian part but Khoor Abdullah and Kuwait bay meandered westerly in the Arabian part, they are distributed symmetrically with respect to axis of Persian Gulf(PG), these two are fractal components of easterly Caspian-wing and westerly Black Sea-wing which split up from Anatoly. Caspian Sea and Black Sea make two legs of Y-like structure, this shape completely fitted with GPS-velocity map which start from PG and split up in the Catastrophic Point(Anatoly). We could consider PG as remnants of Ancient Ocean which spent up

  13. The geometry of the Wadati-Benioff zone under southern Central America and its tectonic significance: results from a high-resolution local seismographic network

    NASA Astrophysics Data System (ADS)

    Protti, Marino; Gu¨ndel, Federico; McNally, Karen

    1994-07-01

    We present here a detailed geometry of the Wadati-Benioff zone under Costa Rica, obtained from seismicity recorded by a dense local seismographic network jointly operated by the Costa Rica Volcanological and Seismological Observatory, National University, and the Charles F. Richter Seismological Laboratory, University of California, Santa Cruz. Underneath the Nicaragua-Costa Rica border the Wadati-Benioff zone smoothly contorts (from steep to shallow dip angles, NW to SE), but does not show evidence of a brittle tear, as postulated by others. However, further to the SE, NE of Puerto Caldera, Costa Rica, the Wadati-Benioff zone does show a segmentation (the Quesada Sharp Contortion) at intermediate depths ( h > 70km). NW of this sharp contortion the deepest portion of the seismically active slab dips at about 80° and reaches maximum depths ranging from 200 km, near the Nicaragua-Costa Rica border, to 135 km under Ciudad Quesada. To the SE the deeper portion of the Wadati-Benioff zone dips at about 60° and the seismicity does not extend below depths ranging from 125 km, behind the volcanic arc, to 50 km, east of Quepos. In southern Costa Rica, east of 83°55'W, we find no evidence of the Wadati-Benioff zone deeper than 50 km. The obtained geometry and other known tectonic features related to the subduction of the Cocos plate under the Caribbean plate along the southern terminus of the Middle America Trench (Nicaragua and Costa Rica) correlate well with along-trench variations in age of the subducted Cocos plate. Some of these tectonic features are: (1) the shallowing of Middle America Trench bathymetry from NW to SE; (2) variations in the energy release within the subducted slab; (3) differences in coupling between Cocos and Caribbean plates; (4) the termination of the Central America Volcanic Chain in central Costa Rica; (5) distinct stress field variations on the overriding Caribbean plate. The subduction of the Cocos Ridge under southern Costa Rica is partially

  14. The age and tectonic significance of differences in the succession of FIA trends from Central Colorado to Northern New Mexico: Accessing the history of deformation partitioning during orogenesis

    NASA Astrophysics Data System (ADS)

    Cao, H.; Fletcher, C.

    2010-12-01

    A similar succession of foliation inflection/intersection axis trends preserved within porphyroblasts (FIAs) is present in two areas separated by 200 km along the Rocky Mountains. PreCambrian rocks in Central Colorado and Northern New Mexico were affected by deformation and metamorphism from approximately 1506 to 1370 Ma. A succession of five FIAs trending W-E, SSW-NNE, NNW-SSE, NW-SE and WSW-ENE has been distinguished in Central Colorado that have been dated at 1506±15Ma, 1467±23Ma, 1425±18 Ma, not dated and 1366±20 Ma, respectively. To the south in Northern New Mexico, a succession of five FIAs trending SSW-NNE, WNW-ESE, NNW-SSE, NW-SE and WSW-ENE have been distinguished dated at 1482±48Ma, 1448±12Ma, 1422±35Ma, not dated and 1394±22Ma. Correlation of these FIA successions, trends and ages reveals a six fold FIA succession across the region with the first developed FIA not being present in Northern New Mexico and the third not being present in Central Colorado. Preferential partitioning of W-E trending deformation into the Central Colorado region around 1506±15Ma was followed by SSW-NNE trending deformation that affected both regions at 1470±20 Ma. However, preferential partitioning of WNW-ESE trending deformation into Northern New Mexico at 1448±12 Ma left Central Colorado unaffected. Both regions were then affected by the three remaining periods of orogenesis, the first trending NNW-SSE at 1424±15 Ma followed by one trending NW-SE that has not yet been dated, and then one trending WSW-ENE at 1390±19 Ma. This suggests that the Yavapai terrain was tectonized at approximately 1506 Ma, prior to amalgamation with the Mazatzal terrain around 1470 Ma. Subsequent orogenesis was initially partitioned preferentially into the Mazatzal terrain, but the following three periods of tectonism affected both terrains in a similar manner.

  15. Size distribution and roundness of clasts within pseudotachylytes of the Gangavalli Shear Zone, Salem, Tamil Nadu: An insight into its origin and tectonic significance

    NASA Astrophysics Data System (ADS)

    Behera, Bhuban Mohan; Thirukumaran, V.; Soni, Aishwaraya; Mishra, Prasanta Kumar; Biswal, Tapas Kumar

    2017-06-01

    Gangavalli (Brittle) Shear Zone (Fault) near Attur, Tamil Nadu exposes nearly 50 km long and 1-3 km wide NNE-SSW trending linear belt of cataclasites and pseudotachylyte produced on charnockites of the Southern Granulite Terrane. Pseudotachylytes, as well as the country rock, bear the evidence of conjugate strike slip shearing along NNE-SSW and NW-SE directions, suggesting an N-S compression. The Gangavalli Shear Zone represents the NNE-SSW fault of the conjugate system along which a right lateral shear has produced seismic slip motion giving rise to cataclasites and pseudotachylytes. Pseudotachylytes occur as veins of varying width extending from hairline fracture fills to tens of meters in length. They carry quartz as well as feldspar clasts with sizes of few mm in diameter; the clast sizes show a modified Power law distribution with finer ones (<1000 {\\upmu }m2) deviating from linearity. The shape of the clasts shows a high degree of roundness (>0.4) due to thermal decrepitation. In a large instance, devitrification has occurred producing albitic microlites that suggest the temperature of the pseudotachylyte melt was >1000^{circ }\\hbox {C}. Thus, pseudotachylyte veins act as a proxy to understand the genetic process involved in the evolution of the shear zone and its tectonic settings.

  16. The Deccan tholeiite lavas and dykes of Ghatkopar-Powai area, Mumbai, Panvel flexure zone: Geochemistry, stratigraphic status, and tectonic significance

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu C.; Zellmer, Georg F.; Demonterova, Elena I.; Ivanov, Alexei V.; Kumar, Rohit; Patel, Rakesh Kumar

    2014-04-01

    Mumbai City, situated on the western Indian coast, is well known for exposures of late-stage Deccan pillow basalts and spilites, pyroclastic rocks, rhyolite lavas, and trachyte intrusions. These rock units, and a little-studied sequence of tholeiitic flows and dykes in the eastern part of Mumbai City, constitute the west-dipping limb of a regional tectonic structure called the Panvel flexure. Here we present field, petrographic, major and trace element and Sr-Nd isotopic data on these tholeiitic flows and dykes, best exposed in the Ghatkopar-Powai area. The flows closely resemble the Mahabaleshwar Formation of the thick Western Ghats sequence to the east, in Sr-Nd isotopic ratios and multielement patterns, but have other geochemical characteristics (e.g., incompatible trace element ratios) unlike the Mahabaleshwar or any other Formation. The flows may have originated from a nearby eruptive center, possibly offshore of Mumbai. Two dykes resemble the Ambenali Formation of the Western Ghats in all geochemical characteristics, though they may not represent feeders of the Ambenali Formation lavas. Most dykes are distinct from any of the Western Ghats stratigraphic units. Some show partial (e.g., Sr-Nd isotopic) similarities to the Mahabaleshwar Formation, and these include several dykes with unusual, concave-downward REE patterns suggesting residual amphibole and thus a lithospheric source. The flows and dykes are inferred to have undergone little or no contamination, by lower continental crust. Most dykes are almost vertical, suggesting emplacement after the formation of the Panvel flexure, and indicate considerable east-west lithospheric extension during this late but magmatically vigorous stage of Deccan volcanism.

  17. Tectonic significance of magnetic and gravity data across northern California (lat. 39[degree]N. to lat. 41[degree]N. )

    SciTech Connect

    Griscom, A.; Roberts, C.W.; Halvorson, P.F. )

    1993-04-01

    Aeromagnetic and isostatic residual gravity maps of an east-west transect across northern California show important tectonic features. A linear magnetic anomaly and west-sloping gradient extends over 300 km along the Franciscan-Great Valley contact (FGC) and across the Klamath Mountains province (KM) north to lat. 40[degree]45'N. The anomaly source lies at depths of 5--10 km beneath the KM and the FGC, and implies that the Franciscan complex of the Coast Ranges is thrust (and wedged) at least 80 km eastward beneath the KM to approximately long. 122[degree]40 minutes W. Calculations on a circular gravity low of [minus]50 mGal centered at the circular Bald Rock pluton (diameter about 15 km) in the Sierran foothills indicate a pluton thickness of about 15 km. The nearby Cascade and Merrimac plutons are located on the gradients of this gravity anomaly, have a relatively minor effect on it, and thus are interpreted to be thick (up to 5 km) laccolithic sills that emanate from the Bald Rock pluton, thinning away from it to a feather edge. Model studies indicate that the northeast contact of the Feather River periodotite body (FRPB) north of lat. 39[degree]40 minutes N. generally dips steeply northeast or vertical. The same contact south of this latitude dips east at angles of about 45[degree] to depths of at least 10 km. Magnetic patterns extending from the northern Sierra across the Cascades to the Klamath Mountains suggest that the FRPB may correlate with the Trinity ophiolite.

  18. Crustal structure across the post-spreading magmatic ridge of the East Sub-basin in the South China Sea: Tectonic significance

    NASA Astrophysics Data System (ADS)

    He, Enyuan; Zhao, Minghui; Qiu, Xuelin; Sibuet, Jean-Claude; Wang, Jian; Zhang, Jiazheng

    2016-05-01

    The 140-km wide last phase of opening of the South China Sea (SCS) corresponds to a N145° direction of spreading with rift features identified on swath bathymetric data trending N055° (Sibuet et al., 2016). These N055° seafloor spreading features of the East Sub-basin are cut across by a post-spreading volcanic ridge oriented approximately E-W in its western part (Zhenbei-Huangyan seamounts chain). The knowledge of the deep crustal structure beneath this volcanic ridge is essential to elucidate not only the formation and tectonic evolution of the SCS, but also the mechanism of emplacement of the post-spreading magmatism. We use air-gun shots recorded by ocean bottom seismometers to image the deep crustal structure along the N-S oriented G8G0 seismic profile, which is perpendicular to the Zhenbei-Huangyan seamounts chain but located in between the Zhenbei and Huangyan seamounts, where topographic changes are minimum. The velocity structure presents obvious lateral variations. The crust north and south of the Zhenbei-Huangyan seamounts chain is ca. 4-6 km in thickness and velocities are largely comparable with those of normal oceanic crust of Atlantic type. To the south, the Jixiang seamount with a 7.2-km thick crust, seems to be a tiny post-spreading volcanic seamount intruded along the former extinct spreading ridge axis. In the central part, a 1.5-km thick low velocity zone (3.3-3.7 km/s) in the uppermost crust is explained by the presence of extrusive rocks intercalated with thin sedimentary layers as those drilled at IODP Site U1431. Both the Jixiang seamount and the Zhenbei-Huangyan seamounts chain started to form by the intrusion of decompressive melt resulting from the N-S post-spreading phase of extension and intruded through the already formed oceanic crust. The Jixiang seamount probably formed before the emplacement of the E-W post-spreading seamounts chain.

  19. Using remote sensing and GIS techniques to determine the tectonic significance of small-scale surface water runoff in Canyonlands National Park

    NASA Astrophysics Data System (ADS)

    Levoir, M. A.; Mueller, K. J.

    2010-12-01

    by InSAR). These data confirm the influence of surface water runoff on tectonic subsidence in at least 30% of cases, and close to 100% where high-order streams cross faults. Although our work suggests that infiltration of surface water runoff increases localized areas of subsidence by 100-200%, large-scale patterns of strain (~20-30% of the fault array) are likely driven by contributions from other processes such as groundwater influx.

  20. Behavior of Eupcheon fault Using Fault Monitoring Data in South Korea

    NASA Astrophysics Data System (ADS)

    Cho, S.; Hwang, J.; Park, D.; Choi, W.; Chang, C.

    2013-12-01

    In the early 1960s, the Fault Monitoring System(FMS) was adopted in several countries including U.S., Japan and Taiwan, where fault movement related with tectonics have occurred frequently. In Korea, only the Korea Hydro & Nuclear Power Co. Ltd. - Central Research Institute (KHNP-CRI) has been managing FMS. The first FMS of South Korea had been installed to monitor the Eupcheon fault located in Gyeoungju city from 2009. The system is equipped with in-situ measuring units including strainmeter, creepmeter, Global Navigation Satellite System (GNSS), seismometer, and groundwater level meter. This paper presents the behavior of the Eupcheon fault based on the monitored data from EFMS in 2012. These data reveal that the earthquakes near Eupcheon fault did not lead to considerable changes in underground stress and displacement as the data in 2011. The creepmeter is sensitive to the temperature so that the data from the creepmeter showed the seasonal variation. The GNSS and strainmeter data have influenced by the tides. For this reason, it is required to employ a calibration system considering the external parameters such as tides and temperature variations. The KHNP-CRI is currently developing technical systems for data correction and analysis to predict the long-term behavior characteristics of Eupcheon fault. It is expected that the enhanced monitoring system contributes significantly in geo-tectonic safety assessment of nuclear plants and other critical facilities related to the national security.

  1. Vortical Tectonics

    NASA Astrophysics Data System (ADS)

    Mirlin, Eugeny; Mironov, Yury

    2010-05-01

    It is shown that lithospheric plates in their movement on Earth's surface do not undergo typical rotations, as was previously believed, but rather movements of more complicated type, namely vortical (or "whirl"). The specific character of vortical movements is reflective in next various structural-tectonic phenomena at global, regional, and local levels: 1. Propagating of axis of spreading with simultaneous whirling in the appropriate direction, which accompanies the opening of the oceanic basin independently of its size and age. Due to the high instability of rift-genesis and spreading processes, along with main "steam" of rift and spreading there are side "branches" branching off and developing. These are also characterized by vortical type of evolution, and they die out in time; 2. Formation of various scale "embedding" structures - into the smooth and rounded contours of oceanic basins, there are formed by vortical flow, as though a broken, stepped geometry of passive margins is embedded. This is, like segmentation of oceanic bottom, in general, the result of invariable presence of shear component inside a vortex; 3. Formation of tectonic stratification of the oceanic lithosphere, which appears as a consequence of differential rotation of various-scaled volumes of substances in a vortical flow. This causes the vortical differential of the oceanic lithosphere into particular lithospheric layers, which are moving relative to each other along a near-horizontal interface of surfaces; 4. The appearance of tension-compression deformations, cyclically superseding each other in time and space, in a zone of lithospheric accretion at crests of mid-oceanic ridges. The change is caused by the independent rotation of the crust's blocks being moved by vortical flow; here, the gradient of transition from compression to tension increases as the vortical system whirls; 5. Formation of structures of the Earth's crust, caused by the compressive tensions in the region of maximal

  2. Tectonic Significance of Cretaceous to Tertiary Magmatic and Structural Evolution of the Northern Portion of the Xolapa Complex, Tierra Colorada-Acapulco Area, Southern Mexico

    NASA Astrophysics Data System (ADS)

    Torres de Leon, R.; Perez, R.; Solari, L.; Hernandez, G.; Sole, J.; Solis, G.; Hernandez, T.

    2007-05-01

    middle Cretaceous. The stable conditions during deposition of the Morelos Formation may have resulted from a combination of back-arc extension and development of a passive margin during the Middle Cretaceous, which postdated the accretion of an exotic block, either the Guerrero terrane or the Chortís block. Following the Laramide Orogeny in southern Mexico (roughly during the Late Cretaceous) the Paleocene to Miocene tectonic evolution is represented by an alternation of magmatic pulses with contractile and extensional events, which are the result of a combination of several factors such as the geometry of the subducted slab, convergence rate, stress transmission between subducting and overlying plate, as well as to the rate of subduction erosion.

  3. Intermittent Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Silver, P. G.; Behn, M. D.

    2006-12-01

    prevent the ultimate closure of the Pacific basin and thus the cessation of subduction. More noteworthy is where subduction is not initiating. First, there is no evidence for subduction initiation anywhere within the Atlantic basin (excluding the Caribbean and Scotia), despite the mature 100-200 my age of passive-margin oceanic lithosphere. The formation of the Alpine-Himalayan chain represents the cessation of roughly 10,000 km of subduction at about 35-50 ma, Yet, no new subduction zones have initiated south of India or Africa, the two major continents that participated in the collision. These examples illustrate that subduction does not immediately initiate following a continent-continent collision, and may lag by 10s if not 100s of millions of years. The stoppage of plate tectonics, or even a dramatic reduction in subduction flux, would have significant thermal consequences for the mantle. It would effectively mark a temporary switch to "stagnant-lid" tectonics, analogous to that found on Venus, resulting in a significant increase in global mantle potential temperature (30- 100°C per 100 my) and a possibly widespread increase in magmatic activity. Such a hiatus may have occurred in the Mid-Proterozoic (1.1-1.6Ga), an era characterized by the virtual absence of orogenic activity, the longest-lived passive margin (600 My), and the production of enigmatic "anorogenic" granites found over thousands of kilometers in a belt presently stretching from southwestern to northeastern North America.

  4. Tectonic Maps of the Poles

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These tectonic relief maps of the north (left, view large [540k]) and south (right, view large [411k]) poles are the result of new satellite-based technologies which are being used to analyze tectonic activity in the Earth's crust. These maps, known as Digital Tectonic Activity Maps (DTAMs), synoptically depict the architecture of the Earth's crust including current and past tectonic activity. This is significant because it permits researchers to view broad zones of activity over the entire surface of the Earth, rather than focusing on single boundary features. By looking at these 'big pictures,' scientists can possibly identify regions of activity which were not previously recognized or mapped using traditional methods. For more information, see: DTAM web site Putting Earthquakes in Their Place Images courtesy Brian Montgomery, NASA GSFC; data by Paul Lowman and Jacob Yates, NASA GSFC

  5. Tectonic Maps of the Poles

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These tectonic relief maps of the north (left, view large [540k]) and south (right, view large [411k]) poles are the result of new satellite-based technologies which are being used to analyze tectonic activity in the Earth's crust. These maps, known as Digital Tectonic Activity Maps (DTAMs), synoptically depict the architecture of the Earth's crust including current and past tectonic activity. This is significant because it permits researchers to view broad zones of activity over the entire surface of the Earth, rather than focusing on single boundary features. By looking at these 'big pictures,' scientists can possibly identify regions of activity which were not previously recognized or mapped using traditional methods. For more information, see: DTAM web site Putting Earthquakes in Their Place Images courtesy Brian Montgomery, NASA GSFC; data by Paul Lowman and Jacob Yates, NASA GSFC

  6. Upper-crust Tomographic Structure of the Southern Korea Peninsula from Local Earthquakes

    NASA Astrophysics Data System (ADS)

    Kim, K. H.; Park, J. H.; Kang, S. Y.

    2015-12-01

    We derived the three dimensional P wave velocity model for the uppermost 14 km of crust in the southern Korea peninsula using travel-time data from local earthquakes which are recorded by two nation-wide seismic networks operated by Korea Meteorological Administration and Korea Institute of Geoscience and Mineral Resources. Earthquakes in the study occurred between 2001 and 2014. 19,935 P wave arrivals from 747 earthquakes observed by 184 seismic stations are selected for the 3-D tomographic inversion. In order to secure best possible data for tomography inversion, we applied a strict criteria during the selection of earthquakes and travel-times. The study area is parameterized by 10km×10km×4km grid for velocity inversion and 1km×1km×1km grid for travel time calculations. Checkerboard resolution test are used to demonstrate the ray coverage and the resolution for the given station-event configurations. The results indicate P-wave velocity model at shallow depths less than 2 km are not properly resolved mainly due to the insufficient ray coverage. The model at deeper depths greater than 14 km also suffered by lack of ray coverage. Thus, we limit our interpretations of the preliminary P wave velocity model to areas that are illuminated by enough rays. P wave velocity model indicates there are significant lateral velocity variations across the southern Korea peninsula. Most distinguished feature in the velocity model is the higher velocity anomaly beneath the southeastern Korea peninsula. The anomaly regions is distinguished by well-defined tectonic boundary. At 8 km depth, lower velocity anomaly is observed in Gyeonggi massif and high-mountain regions in the southern Korea peninsula. The 3-D velocity model is compared with geophysical and geological observations.

  7. The exploration potential of offshore northwest Korea (P. D. R. K. )

    SciTech Connect

    Cunningham, P.; Bishopp, D. )

    1991-03-01

    Recent political changes have demonstrated that previously taboo countries are now becoming fair game for western explorationists. Numerous areas or basins that have not been the focus of high technology - Technologically Attenuated Basins (TABs) - offer a new challenge for the new venture groups of E and P companies. Most recently the USSR together with other Eastern European countries continue to be a source of technical interest and frustration. The People's Democratic Republic of Korea, North Korea, possibly the most isolated of the Communist block, contains several TABs where there has been minimal exploration. One such TAB is West Korea Bay, which covers an area of 25,000 km{sup 2} containing at least one major Tertiary basin. The tectonic evolution of the Tertiary basin is similar to the intracratonic Chinese basins with significant differences, notably the Songnim and Daebo orogenies (Middle Triassic to Upper Jurassic and Jurassic to middle Cretaceous) that resulted in extensive igneous activity, folding, and thrust faulting, followed by an extensional stress regime during the Mesozoic and Cainozoic. Very few wells have been drilled in West Korea Bay in the past decade (one per 2,500 km{sup 2}). Though commercially unsuccessful, the wells have proven the existence of oil, mature source rocks, and reservoirs (Jurassic, Cretaceous, and Oligo-Miocene). Structural plays such as rotated Jurassic and Cretaceous fault blocks predominate, but there is also potential for higher risk stratigraphic potential in the Jurassic and Tertiary, with expected field size distributions in the 20-180 MMBOR range.

  8. Global Tectonics on Ganymede

    NASA Technical Reports Server (NTRS)

    Thomas, P. G.; Forni, O. P.; Masson, P. L.

    1985-01-01

    Three large basin surroundings on Ganymede located on grooved terrains, which are supposed to be intensely tectonized areas were studied. All rectilinear morphological elements such as ridges, block edges; and parts of scarps were mapped. The geometric properties (grid pattern) characteristics were determined and a history for the formation of the Ganymede basins studied is proposed. Results indicate that the grooved terrains are very surficial layers, and that their formation does not significantly affect, disturb or rotate the basement. This is in agreement with the conclusion obtained from completely different data (crosscutting relationships between groove sets and their basements).

  9. Recent Advances in Mars Tectonics

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Banerdt, W. B.

    1999-01-01

    Since the publication of the "Stress and Tectonics on Mars" chapter in the Mars book (the last comprehensive summary of our knowledge on the topic) considerable advances have been made in certain areas of Martian tectonics and significant advances are expected with the return of Mars Global Surveyor data. This abstract will summarize the advances in our knowledge of tectonic features and processes on Mars since the Mars book and point towards new areas of research that can be expected from the Mars Global Surveyor data. Two out of three areas of study that were discussed as future directions of work in the Mars chapter have had significant work directed towards them. One area is the field of structural mapping and understanding the timing of tectonic activity on Mars in the framework of the global stratigraphy. Although the general development and relative timing of the development of the Tharsis province on Mars had been understood for some time, actual placement of mapped tectonic features in a global stratigraphic framework has only recently been completed. The second area of study mentioned in the Mars chapter was the impact of improved topography and gravity on modeling loads and deriving stresses in the Martian lithosphere. Mars Global Surveyor is on the brink of returning vastly improved topographic and gravity fields and these newer data sets can be used to better define the size and shape of Tharsis and to quantify loads and derived stresses in the Martian lithosphere. Additional information is contained in the original extended abstract.

  10. Recent Advances in Mars Tectonics

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Banerdt, W. B.

    1999-01-01

    Since the publication of the "Stress and Tectonics on Mars" chapter in the Mars book (the last comprehensive summary of our knowledge on the topic) considerable advances have been made in certain areas of Martian tectonics and significant advances are expected with the return of Mars Global Surveyor data. This abstract will summarize the advances in our knowledge of tectonic features and processes on Mars since the Mars book and point towards new areas of research that can be expected from the Mars Global Surveyor data. Two out of three areas of study that were discussed as future directions of work in the Mars chapter have had significant work directed towards them. One area is the field of structural mapping and understanding the timing of tectonic activity on Mars in the framework of the global stratigraphy. Although the general development and relative timing of the development of the Tharsis province on Mars had been understood for some time, actual placement of mapped tectonic features in a global stratigraphic framework has only recently been completed. The second area of study mentioned in the Mars chapter was the impact of improved topography and gravity on modeling loads and deriving stresses in the Martian lithosphere. Mars Global Surveyor is on the brink of returning vastly improved topographic and gravity fields and these newer data sets can be used to better define the size and shape of Tharsis and to quantify loads and derived stresses in the Martian lithosphere. Additional information is contained in the original extended abstract.

  11. Tsunami Catalog in Korea

    NASA Astrophysics Data System (ADS)

    Jin, Sobeom; Hyun, Seung Gyu; Noh, Myunghyun

    2015-04-01

    Significant tsunamis are described in historic and instrumental earthquake sources for all regions around the Korean Peninsula. According to the low seismicity near the Peninsula, there are relatively few tsunami events in Korea. Most of the tsunami events are associated with big earthquakes at the eastern margin of the East Sea. One historical event is associated with a volcanic eruption. For that reason, the eastern coast of the Korean Peninsula is the affectable area for tsunami. One historical event at the Yellow Sea area is inferred a result from a big earthquake in China. And one plate boundary earthquake between the Philippine Plate and the Eurasian Plate affected to an island located in south of the Korean Peninsula. We confirmed the historic tsunami events by review the foreign literatures. More detailed information is presented for the instrumental earthquake source events. This work was supported by the Nuclear Safety Research Program through the Korea Radiation Safety Foundation (KORSAFe) and the Nuclear Safety and Security Commission (NSSC), Republic of Korea (Grant No. 1305001).

  12. The deformation pattern and SHRIMP U-Pb zircon ages of a Neoproterozoic meta-volcano-sedimentary formation in the Northern Gyeonggi Massif, South Korea, and the implications for tectonic correlation with the southern margin of the North China Craton

    NASA Astrophysics Data System (ADS)

    Singh, Y. K.; Lee, J. Y.; Oh, C. W.; Yi, K.

    2016-12-01

    The Neoproterozoic igneous activities in the Korean peninsula are correlated to the assembly and break-up of the Rodinia supercontinent. However, the Neoproterozoic activities are still poorly understood in the Northern Gyeonggi Massif (NGM) in the Korean peninsula until now. Our new finding of a Gapyeong Formation (GF) in the southern margin of the NGM provides important evidence of rifting-related igneous activities during the Neoproterozoic, metamorphism and deformation during the Permo-Triassic events. The GF is a Neoproterozoic meta-volcano-sedimentary formation and overlies the Paleoproterozoic basement gneisses via a sheared contact. Based on the structural analysis we identified three different folds - F1, F2 and F3 correspond to three stages of deformation - D1, D2 and D3, respectively. The F1 folding is a result of E-W compression during the Paleoproterozoic deformation (D1). The F2 folding and mylonitization characterized by top-down-to-the-NNE shearing are correlated to main ductile shearing during the Permo-Triassic extensional deformation (D2). The F3 folding formed through ESE-WNW compression is correlated to the Triassic or early Jurassic deformation (D3). The SHRIMP U-Pb dating of the basement gneisses suggest two distinct protoliths: a ca. 2.5 Ga granitoid and sediments deposited after ca. 2.27 Ga. The basement gneisses experienced two major metamorphic Pb-loss events: the earliest during 1899-1895 Ma and the second during the Permo-Triassic. However, the GF gives protolith ages of 854-740 Ma and metamorphic ages of 260-245 Ma. By combining crystallization age of the protoliths and whole-rock geochemistry, we suggest that the GF was formed by bimodal volcanism in the continental rift tectonic setting and this ca. 854 Ma rifting-related magmatism in the NGM is correlated to the Neoproterozoic rifting-related igneous activities during the break-up of the Rodinia supercontinent along the southern margin of the North China Craton.

  13. Stress and tectonics on Mars

    NASA Technical Reports Server (NTRS)

    Banerdt, W. B.; Golombek, Matthew P.; Tanaka, Kenneth L.

    1992-01-01

    Deformation of the Martian lithosphere and the various theoretical formulations used to model its behavior on local, regional, and global scales are studied. An overview of the various classes of tectonic features found on Mars is presented. The tectonic record on Mars, which provides the basic framework for interpreting theoretical thermomechanical models in terms of major tectonic events and provinces is summarized. The thickness of the elastic lithosphere is estimated using its response to local surface loads, and significant spatial variability is found, with values ranging from 20 to 300 km. A comparison of the major radial graben systems with theoretical stress models shows that more than one mechanism of lithospheric deformation is required to produce its enormous extent.

  14. The tectonics of Mercury

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Mckinnon, W. B.

    1988-01-01

    The probable tectonic history of Mercury and the relative sequence of events are discussed on the basis of data collected by the Mariner-10 spacecraft. Results indicate that Mercury's tectonic activity was confined to its early history; its endogenic activity was principally due to a small change in the shape of its lithosphere, caused by tidal despinning, and a small change in area caused by shrinkage due to cooling. Exogenic processes, in particular the impact activity, have produced more abundant tectonic features. Many features associated with the Caloris basin are due to loading of Mercury's thick lithosphere by extrusive lavas or subsidence due to magma withdrawal. It is emphasized that tectonic features observed on Mercury yield insight into the earliest tectonic events on planets like Mars and, perhaps, the earth, where subsequent events obscured or erased the most ancient tectonic records.

  15. Geomorphology, tectonics, and exploration

    NASA Technical Reports Server (NTRS)

    Sabins, F. F., Jr.

    1985-01-01

    Explorationists interpret satellite images for tectonic features and patterns that may be clues to mineral and energy deposits. The tectonic features of interest range in scale from regional (sedimentary basins, fold belts) to local (faults, fractures) and are generally expressed as geomorphic features in remote sensing images. Explorationists typically employ classic concepts of geomorphology and landform analysis for their interpretations, which leads to the question - Are there new and evolving concepts in geomorphology that may be applicable to tectonic analyses of images?

  16. Tectonics on Triton

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1993-01-01

    Tectonic features on Triton have been mapped as part of a larger study of the geology of Triton. Few purely tectonic structures are found on Triton: some grabens and possibly some compressive ridges. However, most of the other structures seen (primarily cryovolcanic in origin) exhibit tectonic control. A regional tectonic network has the following dominant orientations: N-S, E-W, NE-SW, and NW-SE. Most of the orientations are consistent with tidal deformations related to Triton's decreasing orbital radius. Localized quasi-concentric patterns may be due to interior processes such as mantle plumes.

  17. Tectonic features on Titan

    NASA Astrophysics Data System (ADS)

    Cook, C.; Barnes, J.

    2011-10-01

    This research is based on the exploration of tectonic patterns on Titan from a global perspective. Several moons in the outer solar system display known stress fields driven or modified by global forces which affect patterns of tectonism. Patterns such as these are seen in Europa's tidal forces, Enceladus' tiger strips, and Ganymede's global expansion. Given its proximity to Saturn, as well as its eccentric orbit, tectonic features and global stresses may be present on Titan as well. Titan displays visible tectonic structures, such as mountain chains along its equator (Radebaugh et al. 2007), as well as the unexplored Virgae.

  18. Tectonics on Triton

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1993-01-01

    Tectonic features on Triton have been mapped as part of a larger study of the geology of Triton. Few purely tectonic structures are found on Triton: some grabens and possibly some compressive ridges. However, most of the other structures seen (primarily cryovolcanic in origin) exhibit tectonic control. A regional tectonic network has the following dominant orientations: N-S, E-W, NE-SW, and NW-SE. Most of the orientations are consistent with tidal deformations related to Triton's decreasing orbital radius. Localized quasi-concentric patterns may be due to interior processes such as mantle plumes.

  19. Earthquakes and plate tectonics

    USGS Publications Warehouse

    Spall, H.

    1977-01-01

    An explanation is to be found in plate tectonics, a concept which has revolutionized thinking in the Earth sciences in the last 10 years. The theory of plate tectonics combines many of the ideas about continental drift (originally proposed in 1912 by Alfred Wegener in Germany) and sea-floor spreading (suggested originally by Harry Hess of Princeton University). 

  20. Neoproterozoic transpression and granite magmatism in the Gavilgarh-Tan Shear Zone, central India: Tectonic significance of U-Pb zircon and U-Th-total Pb monazite ages

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Anupam; Chatterjee, Amitava; Das, Kaushik; Sarkar, Arindam

    2017-10-01

    The Gavilgarh-Tan Shear Zone (GTSZ) is a crustal-scale shear/fault zone that dissects the unclassified basement gneisses separating two major supracrustal belts, viz. the Paleo- to Mesoproterozoic (≥1.5 Ga) Betul Belt and the Neoproterozoic (∼1.0 Ga) Sausar Belt, of the Central Indian Tectonic Zone (CITZ). The GTSZ extends for more than 300 km strike length, partly covered by the Deccan Trap flows. Granitoid rocks ranging from syenogranite to granodiorite in composition, sheared at temperatures corresponding to the amphibolite facies metamorphic condition, define the GTSZ in the Kanhan River Valley. Earlier geological studies have suggested that the GTSZ underwent a sinistral-sense partitioned transpression in response to an oblique collision between two continental fragments, possibly related to crustal thickening and high-pressure granulite metamorphism (the Ramakona-Katangi granulite: RKG) in the northern part of the Sausar Belt. LA-ICP-MS U-Pb dating of zircon and EPMA U-Th-total Pb dating of monazite grains from four different types of syn-tectonic granitoids of the GTSZ carried out in the present study show that granitoids intruded the basement gneisses between 1.2 Ga and 0.95 Ga, given the error limit of the calculated ages. The age of transpression and mylonitization is more definitely bracketed between 1.0 Ga and 0.95 Ga, which correlates well with the published ages of deformation and metamorphism in the Sausar Belt. This age data strongly supports the suggested collisional tectonic model involving the GTSZ and the RKG granulites of the Sausar Belt and underlines a Grenvillian-age tectonic history for the southern part of the Central Indian Tectonic Zone (CITZ), which possibly culminated in the crustal assembly of the Neoproterozoic supercontinent Rodinia.

  1. Nation Building in Korea

    DTIC Science & Technology

    1995-04-01

    opportunity to rebuild South Korea . He saw it as “something almost unique in history. It is the opportunity of an army in a foreign land to contribute...problems. The North Korean invasion in 1950 wedded South Korea to the United States and confronted the United States with the enormous task of...elections in Korea .8 After failing to achieve agreement to peninsula-wide elections, the United Nations sponsored elections in South

  2. Planetary Tectonics and Volcanism

    NASA Technical Reports Server (NTRS)

    Zuber, Maria T.

    1997-01-01

    The study of tectonic and volcanological processes on the terrestrial planets, with particular emphasis on Venus, in order to better understand the internal structures and thermal and stress histories of these bodies is reported.

  3. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  4. Plate tectonics: Metamorphic myth

    NASA Astrophysics Data System (ADS)

    Korenaga, Jun

    2016-01-01

    Clear evidence for subduction-induced metamorphism, and thus the operation of plate tectonics on the ancient Earth has been lacking. Theoretical calculations indicate that we may have been looking for something that cannot exist.

  5. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  6. Whither Unified Korea? East, West or Center?

    DTIC Science & Technology

    2015-02-17

    the balance of power in Northeast Asia has been significantly shaped by an enduring Republic of Korea (ROK)-US alliance. Despite the constant threat of...a resumption of hostilities between the two Koreas, the current structure maintains a status quo that assures the balance of power in Northeast Asia...the balance of power imposed on the region since 1953. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report

  7. Coupled Tectonic and Climatic Shifts in Planetary Evolution

    NASA Astrophysics Data System (ADS)

    Weller, M. B.; Lenardic, A.; Jellinek, M.

    2016-12-01

    Growing evidence suggests that the tectonic mode of the Earth has changed over its geologic lifetime. During a tectonic regime shift, the planet will be very far from any dynamic equilibrium point and, as such, standard thermal history modelling will not be applicable. A regime shift will also be associated with changes that can effect the large scale climate of a planet. Recently it has been shown that significant feedbacks are possible between planetary tectonics and the climate of a planet [e.g., 1, 2, and references therein]. How those feedbacks operate during a tectonic regime shift (e.g., the initiation of plate-tectonics) has, to date, not been fully explored. To explore linked tectonic-climate effects, during transitions between tectonic states, we couple 3D mantle convection and planetary tectonics simulations to climate models. A planet initially in a single plate state can transition to a plate-tectonic like mode as it cools. Initial lithosphere yielding, for systems with moderate convective vigor, results in an increase of pCO2 by a factor of 50 - 100 (from increased melt production), indicating that the onset of global subduction, may be significant driver of the atmospheric, in addition to the tectonic evolution. All else being held equal, the initiation time of yielding as well as the planetary position within the Solar System allow for results ranging from a climatic shutdown of an incipient mode of plate-tectonics, to a buffered atmosphere and long lived plate-tectonics, to a final 'dead snowball state'. These results illustrate the need to think of tectonics and habitably within a temporal framework in which tectonic regime shifts can be a first order control on the long term habitability potential of a planet. [1] Foley et al., (2012) EPSL; [2] Weller et al., (2015) EPSL

  8. Plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1981-01-01

    The high surface temperature of Venus implies a permanently buoyant lithosphere and a thick basaltic crust. Terrestrial-style tectonics with deep subduction and crustal recycling is not possible. Overthickened basaltic crust partially melts instead of converting to eclogite. Because mantle magmas do not have convenient access to the surface the Ar-40 abundance in the atmosphere should be low. Venus may provide an analog to Archean tectonics on the earth.

  9. What was Earth's tectonic style before Plate Tectonics?

    NASA Astrophysics Data System (ADS)

    Rey, P. F.; Coltice, N.; Flament, N. E.

    2015-12-01

    In the Archean, deep mantle upwelling resulted in the formation of thick, buoyant, hot and therefore weak continental plates, as well as thicker oceanic crusts and plateaux that may have impeded and perhaps prevented modern style subduction. Continents were easy to deform and too weak to support high mountain belts and orogenic plateaux which characterize modern collisional orogens. Overall, it would be very surprising if Archean tectonics processes were similar than those observable today. Over the past decade, numerical experiments have shown that the style of subduction depends on i/ the degree of coupling between the upper and lower plate which controls whether subduction zones are double sided or single sided; ii/ the buoyancy of the subducting plate which controls whether subduction is spontaneous or requires a push and whether slabs retreat or not; iii/ the yield stress of the subducting plate which controls whether recurrent slab breakoff occurs or not. Studies focused on the behaviour of continental plates show that only minor thickening (tectonic or volcanic via the emplacement of continental flood basalts) is required for the crust to reach its solidus, which would have promoted the foundering of greenstone covers into the crust (sagduction). In a convergence setting, weak continents would have deformed easily and convergence mainly accommodated by lateral expulsion and lateral flow under a regional transcurrent tectonic regime. Numerical experiments suggest that thick and buoyant continents would have imparted significant horizontal stresses on adjacent oceanic plates, the slow spreading of thick and buoyant continents leading to the initiation of subduction. Provided that continental lithospheric mantle could spontaneously subduct, numerical experiments suggest that in a convergent setting accretionary orogeny rather than continental collision was a dominant tectonic style with implications for crustal growth and differentiation.

  10. Preliminary publications Book 1 from Project on Mineral Resources, Metallogenesis and Tectonics of Northeast Asia

    USGS Publications Warehouse

    Ariunbileg, Sodov; Badarch, Gombosuren; Berzin, Nikolai A.; Bulgatov, Alexander N.; Chimed, Noosoi; Deikunenko, Aleksey V.; Dejidmaa, Gunchin; Diggles, Michael F.; Distanov, Elimir G.; Dorjgotov, Dangindorjiin; Gerel, Ochir; Gordienko, Ivan V.; Gotovsuren, Ayurzana; Hwang, Duk-Hwan; Khanchuk, Alexander I.; Koch, Richard D.; Miller, Robert J.; Nokleberg, Warren J.; Obolenskiy, Alexander A.; Ogasawara, Masatsugu; Orolmaa, Demberel; Oxman, Vladimir S.; Parfenov, Leonid M.; Popeko, Ludmila I.; Prokopiev, Andrey V.; Smelov, Alexander P.; Sotnikov, Vitaliy I.; Sudo, Sadahisa; Timofeev, Vladimir F.; Tret'yakov, Felix F.; Vernikovsky, Valery A.; Ye, Mao; Zadgenizov, Alexander P.

    1999-01-01

    This report consists of preliminary data tables, maps, and interpretative articles compiled in late 1997 and early 1998 for a new project on the Mineral Resources, Metallogenesis, and Tectonics of Northeast Asia (Eastern and Southern Siberia, Mongolia, North-eastern China, South Korea, and Japan).

  11. The Geography of Korea.

    ERIC Educational Resources Information Center

    Park, Young-Han

    1988-01-01

    Briefly surveys the geography of both North and South Korea, examining mountain ranges, rivers, soil, and climate. Also discusses the economic activities of South Korea, including industrialization, transportation, population, and the urban system. Provides a map of the Korean peninsula and a table of land area and population by province. (GEA)

  12. Active tectonics and human survival strategies

    NASA Astrophysics Data System (ADS)

    King, Geoffrey; Bailey, Geoffrey; Sturdy, Derek

    1994-10-01

    Tectonic movements continuously remould the surface of Earth in response to plate motion. Yet such deformation is rarely taken into account when assessing landscape change and its impact on human land use, except perhaps as an occasional hazard to human life or a temporary disruption in the longer term patterns of human history. However, active tectonics also create and sustain landscapes that can be beneficial to human survival, forming a complex topography of potentially fertile sedimentary basins enclosed by mountain barriers that can facilitate the control and explotation of food resources, especially animal prey. We discuss the tectonic history of northwest Greece and show how the Paleolithic sites of the region are located to take advantage of tectonically created features at both a local and a regional scale. We suggest that the association of significant concentrations of early Paleolithic sites with tectonically acitve regions is not coincidental and that on the longer time spans of human biological evolution, active tectonics has been an important selective agent contributing to the development of the human species as an intelligent predator.

  13. Terrorism in South Korea.

    PubMed

    Wang, Soon Joo; Choi, Jin Tae; Arnold, Jeffrey

    2003-01-01

    South Korea has experienced > 30 suspected terrorism-related events since 1958, including attacks against South Korean citizens in foreign countries. The most common types of terrorism used have included bombings, shootings, hijackings, and kidnappings. Prior to 1990, North Korea was responsible for almost all terrorism-related events inside of South Korea, including multiple assassination attempts on its presidents, regular kidnappings of South Korean fisherman, and several high-profile bombings. Since 1990, most of the terrorist attacks against South Korean citizens have occurred abroad and have been related to the emerging worldwide pattern of terrorism by international terrorist organizations or deranged individuals. The 1988 Seoul Olympic Games provided a major stimulus for South Korea to develop a national emergency response system for terrorism-related events based on the participation of multiple ministries. The 11 September 2001 World Trade Center and Pentagon attacks and the 2001 United States of America (US) anthrax letter attacks prompted South Korea to organize a new national system of emergency response for terrorism-related events. The system is based on five divisions for the response to specific types of terrorist events, involving conventional terrorism, bioterrorism, chemical terrorism, radiological terrorism, and cyber-terrorism. No terrorism-related events occurred during the 2002 World Cup and Asian Games held in South Korea. The emergency management of terrorism-related events in South Korea is adapting to the changing risk of terrorism in the new century.

  14. Origin of microseism observed in South Korea

    NASA Astrophysics Data System (ADS)

    Sheen, D.; Shin, J.; You, S.; Rhie, J.

    2009-12-01

    Ambient seismic noise has been widely used for imaging crustal structure as an alternative passive source, even where traditional seismic imaging is not possible due to low seismicity. Long before the sensational applications of seismic noise, the origin of the noise has already been studied to understand its nature and characteristics for several decades. In this study, we investigate the origin of microseism observed in South Korea. Annual spectrograms in the microseismic frequency range up to 0.4 Hz show coherent peaks at about 0.2 Hz in the winter, which is at the frequency band of the double-frequency microseism. However, the primary microseism is only rarely observed in South Korea when the Pacific typhoon is close to the Southern Sea of Korea. Polarization analysis and noise cross correlation indicate that the energy of the double-frequency microseism comes dominantly from the east of the Korean Peninsula. Comparison of the results from the operational wave model of the Korea Meteorological Administration and seismic data shows a strong correlation of spectral amplitude of seismic data with the significant wave heights and periods of ocean waves, implying that the primary and the double-frequency microseism observed in South Korea are generated at the Southern Sea of Korea and at nearby shorelines of the east coast of Japan, respectively.

  15. Martian tectonics: A review

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1987-01-01

    It is concluded that Mars was dominated by vertical tectonism more than any of the other terrestrial planets. The structural imprint of the Tharsis and Elysium provinces extends over half the planet, and despite 15 years of debate over the cause of the elevation, volcanic activity, and tectonic style of Tharsis, no uniform theory of Tharsis evolution has been generally agreed upon. Although several theories have been suggested for the origin of the north-south planetary dichotomy, there is also a lack of a testable, plausible model for that major unknown in Mars' evolution.

  16. Introduction to Regional Geology, Tectonics, and Metallogenesis of Northeast Asia

    USGS Publications Warehouse

    Parfenov, Leonid M.; Badarch, Gombosuren; Berzin, Nikolai A.; Hwang, Duk-Hwan; Khanchuk, Alexander I.; Kuzmin, Mikhail I.; Nokleberg, Warren J.; Obolenskiy, Alexander O.; Ogasawara, Masatsugu; Prokopiev, Andrei V.; Rodionov, Sergey M.; Smelov, Alexander P.; Yan, Hongquan

    2007-01-01

    This introduction presents an overview of the regional geology, tectonics, and metallogenesis of Northeast Asia. The major purposes are to provide a relatively short summary of these features for readers who are unfamiliar with Northeast Asia; a general scientific introduction for the succeeding chapters of this volume; and an overview of the methodology of metallogenic and tectonic analysis employed for Northeast Asia. The introduction also describes how a high-quality metallogenic and tectonic analysis, including synthesis of an associated metallogenic-tectonic model will greatly benefit refinement of mineral deposit models and deposit genesis; improvement of assessments of undiscovered mineral resources as part of quantitative mineral resource assessment studies; land-use and mineral exploration planning; improvement of interpretations of the origins of host rocks, mineral deposits, and metallogenic belts; and suggestions for new research. The compilation, synthesis, description, and interpretation of metallogenesis and tectonics of major regions, such as Northeast Asia (Eastern Russia, Mongolia, northern China, South Korea, and Japan) and the Circum-North Pacific (Russian Far East, Alaska, and Canadian Cordillera) requires a complex methodology. The methodology includes: (1) definitions of key terms; (2) compilation of a regional geologic base map that can be interpreted according to modern tectonic concepts and definitions; (3) compilation of a mineral deposit database that enables the determination of mineral deposit models, and relations of deposits to host rocks and tectonic origins; (4) synthesis of a series of mineral deposit models that characterize the known mineral deposits and inferred undiscovered deposits of the region; (5) compilation of a series of maps of metallogenic belts constructed on the regional geologic base map; and (6) formulation of a unified metallogenic and tectonic model. The summary of regional geology and metallogenesis in this

  17. Introduction, Chapter 1 in Metallogenesis and tectonics of northeast Asia

    USGS Publications Warehouse

    Parfenov, Leonid M.; Badarch, Gombosuren; Berzin, Nikolai A.; Hwang, Duk-Hwan; Khanchuk, Alexander I.; Kuzmin, Mikhail I.; Nokleberg, Warren J.; Obolenskiy, Alexander A.; Ogasawara, Masatsugu; Prokopiev, Andrei V.; Rodionov, Sergey M.; Smelov, Alexander P.; Yan, Hongquan

    2010-01-01

    The major purposes of this chapter are to provide (1) an overview of the regional geology, tectonics, and metallogenesis of Northeast Asia for readers who are unfamiliar with the region, (2) a general scientific introduction to the succeeding chapters of this volume, and (3) an overview of the methodology of metallogenic and tectonic analysis used in this study. We also describe how a high-quality metallogenic and tectonic analysis, including construction of an associated metallogenic-tectonic model will greatly benefit other mineral resource studies, including synthesis of mineral-deposit models; improve prediction of undiscovered mineral deposit as part of a quantitative mineral-resource-assessment studies; assist land-use and mineral-exploration planning; improve interpretations of the origins of host rocks, mineral deposits, and metallogenic belts, and suggest new research. Research on the metallogenesis and tectonics of such major regions as Northeast Asia (eastern Russia, Mongolia, northern China, South Korea, and Japan) and the Circum-North Pacific (the Russian Far East, Alaska, and the Canadian Cordillera) requires a complex methodology including (1) definitions of key terms, (2) compilation of a regional geologic base map that can be interpreted according to modern tectonic concepts and definitions, (3) compilation of a mineral-deposit database that enables a determination of mineral-deposit models and clarification of the relations of deposits to host rocks and tectonic origins, (4) synthesis of a series of mineral-deposit models that characterize the known mineral deposits and inferred undiscovered deposits in the region, (5) compilation of a series of metallogenic-belt belts constructed on the regional geologic base map, and (6) construction of a unified metallogenic and tectonic model. The summary of regional geology and metallogenesis presented here is based on publications of the major international collaborative studies of the metallogenesis and

  18. Lung Cancer Epidemiology in Korea.

    PubMed

    Shin, Aesun; Oh, Chang-Mo; Kim, Byung-Woo; Woo, Hyeongtaek; Won, Young-Joo; Lee, Jin-Soo

    2017-07-01

    The current study was undertaken to examine the trends in the lung cancer incidence, mortality, and survival after a diagnosis in Korea. Lung cancer incidence data according to the histologic type and mortality data were obtained from the Korea Central Cancer Registry and the Statistics Korea, respectively. The age-standardized incidence and mortality rates were calculated, and the Joinpoint model and age-period-cohort analyses were used to describe the trends in the rates. The 5-year relative survival rates of lung cancer were also calculated. Although the number of new lung cancer cases increased between 1999 and 2012, the age-standardized incidence rate decreased by 0.9% per year in men, whereas the incidence in women increased by 1.7% per year over the same time. Until 2010, the most common histologic type in men was squamous cell carcinoma, then adenocarcinoma prevailed thereafter. Since 1999, the most frequent histological type in women was adenocarcinoma. The lung cancer mortality started to decrease in 2002, with a more apparent decline for the younger age groups in both men and women. Overall, the 5-year relative survival rates have improved significantly from 11.2% for men and 14.7% for women among patients diagnosed between 1993 and 1997 to 19.3% for men and 28.2% for women among patients diagnosed between 2008 and 2012, respectively. An improvement in survival rate was observed for all major histology groups. The epidemiology of lung cancer in Korea has changed over a short time span, with decreasing mortality and improving survival rates. Further study is warranted to determine the cause of these changes.

  19. Mantle plumes and continental tectonics.

    PubMed

    Hill, R I; Campbell, I H; Davies, G F; Griffiths, R W

    1992-04-10

    Mantle plumes and plate tectonics, the result of two distinct modes of convection within the Earth, operate largely independently. Although plumes are secondary in terms of heat transport, they have probably played an important role in continental geology. A new plume starts with a large spherical head that can cause uplift and flood basalt volcanism, and may be responsible for regional-scale metamorphism or crustal melting and varying amounts of crustal extension. Plume heads are followed by narrow tails that give rise to the familiar hot-spot tracks. The cumulative effect of processes associated with tail volcanism may also significantly affect continental crust.

  20. Tectonic Evolution of Mars

    NASA Technical Reports Server (NTRS)

    Phillips, Roger J.

    1992-01-01

    The Final Technical Report on tectonic evolution of Mars is presented. Two papers and an abstract are included. Topics addressed include: scientific rationale and requirements for a global seismic network on Mars, permanent uplift in magmatic systems with application to the Tharsis Region of Mars, and the geophysical signal of the Martian global dichotomy.

  1. Plains Tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Banerdt, W. B.; McGill, G. E.; Zuber, M. T.

    1996-01-01

    Tectonic deformation in the plains of Venus is pervasive, with virtually every area of the planet showing evidence for faulting or fracturing. This deformation can be classified into three general categories, defined by the intensity and areal extent of the surface deformation: distributed deformation, concentrated deformation, and local fracture patterns.

  2. The Plate Tectonics Project

    ERIC Educational Resources Information Center

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  3. The Plate Tectonics Project

    ERIC Educational Resources Information Center

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  4. Task 1 quarternary tectonics

    SciTech Connect

    Bell, J.W.

    1994-12-31

    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  5. The 7th Japan-Korea chemical biology symposium: chemical biology of natural bioactive molecules.

    PubMed

    Pandey, Ramesh Prasad; Kwon, Ho Jeong; Ahn, Jong Seog; Osada, Hiroyuki; Sohng, Jae Kyung

    2014-05-16

    Natural bioactive molecules possess supreme chemical diversity and drug-like properties and are an important source for drug lead compounds. At the seventh Japan-Korea Chemical Biology Symposium at Jeju Island, Korea, chemical biologists from Korea and Japan highlighted the remarkable features of natural products and their significance.

  6. Caldera Ellipticity Through Regional Tectonic Deformation

    NASA Astrophysics Data System (ADS)

    Holohan, E. P.; Troll, V. R.; Walter, T. R.; van Wyk de Vries, B.; Byrne, P. K.

    2005-12-01

    Collapse calderas are delimited by reverse ring faults and surrounded by peripheral concentric normal faults. In the simplest scenario, circular magma chambers produce circular calderas. Many calderas are elliptical in shape, however, particularly those in highly active tectonic settings. Several factors may explain caldera ellipticity in such regimes: 1) Initial geometry of magma chamber(s) 2) Distribution and orientation of pre-existing regional faults, and 3) Influence of the regional stress field on caldera fault geometries. To better understand relationships between caldera morphology, reservoir geometry and regional tectonics, we conducted two analogue experimental series: One series investigated the influence of orthogonal tectonic stresses on caldera and chamber shapes. In all cases where tectonic stress was applied across circular chambers (balloons), elliptical calderas were produced. Pre-existing basement structures also influenced the shape of calderas, either increasing or reducing elongation. Intrusion of silicon gel into tectonically active sand piles showed that silicon gel chambers responded systematically to applied tectonic stress, and that associated calderas would be elliptical in shape. A second series examined the effect of strike slip faulting on magma chambers and associated calderas. We used sand to simulate brittle crust and cream honey to simulate granitic magma. With a sufficiently high transtensive component, pull-apart-like half grabens formed above the passive honey chamber. Chamber evacuation following strike-slip deformation produced arcuate reverse faults that were again occasionally affected by regional structures. From our results, we identify a number of controls for elliptical caldera formation in tectonically active settings, including initial chamber geometry, caldera fault distortion, and interaction with pre-existing structures. Our results indicate that the final caldera surface expression will be the result of interplay

  7. Unraveling Appalachian tectonics: domain analysis of topographic lineaments in Pennsylvania

    NASA Astrophysics Data System (ADS)

    Karimi, B.; Schon, K.; Nussbaum, G. W.; Storer, N. D.; McGuire, J. L.; Hardcastle, K.

    2016-12-01

    Litho-tectonic provinces provide different components of a regions' tectonic history, and are identified as spatial entities with common structural elements, or a number of contiguous related elements. The province boundaries are easily identified when geomorphic expressions are distinct, or significant rock exposure allows for little uncertainty. When exposures are limited, locations of boundaries between provinces are uncertain. In such instances, satellite imagery can be quite advantageous, as tectonically sourced features (faults, folds, fractures, and joints) may exert a strong control on topographic patterns by creating pathways for weathering and erosion. Lineament analyses of topography often focus on well-pronounced tectonic features to interpret regional tectonics. We suggest that lineament analyses including all topographic features may include more subtle tectonic features, resulting in the identification of minor heterogeneities within litho-tectonic provinces. Our study focuses on Appalachian tectonics, specifically in Pennsylvania (PA), home to the Appalachian Orocline and 5 distinct tectonic provinces. Using hillshades from a digital elevation model (DEM) of PA, we manually pick all topographic lineaments 1 km or greater, discriminating only against man-made structures. The final lineament coverage of the state is subdivided into smaller areas for which rose diagrams were prepared. The dominant lineament trends were compared and associated with known structural features. Peaks with no known source are marked as possible tectonic features requiring further research. A domain analysis is performed on the lineament data to identify the extent and interplay of swarms, followed by an investigation of their azimuthal compatibility. We present the results of our domain analysis of all topographic lineaments in the context of identifying litho-tectonic provinces associated with Appalachian tectonics in Pennsylvania, and possible heterogeneities within them.

  8. Studies in geophysics: Active tectonics

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Active tectonics is defined within the study as tectonic movements that are expected to occur within a future time span of concern to society. Such movements and their associated hazards include earthquakes, volcanic eruptions, and land subsidence and emergence. The entire range of geology, geophysics, and geodesy is, to some extent, pertinent to this topic. The needs for useful forecasts of tectonic activity, so that actions may be taken to mitigate hazards, call for special attention to ongoing tectonic activity. Further progress in understanding active tectonics depends on continued research. Particularly important is improvement in the accuracy of dating techniques for recent geologic materials.

  9. When Did Plate Tectonics Begin

    NASA Astrophysics Data System (ADS)

    Brown, M.

    2015-12-01

    Present-day plate tectonics on Earth is characterized by asymmetric (one-sided) subduction, but how do we recognize the imprint of subduction in the geologic record? How do we weigh global (commonly younger) vs local (commonly older) datasets or distinguish initiation from episodic from continuous subduction? How reliable are data gaps? Characteristics of the Paleozoic record of subduction include calc-alkaline magmatism, blueschist/UHP metamorphism and collisional orogenesis, and ophiolites as representatives of former ocean lithosphere. Are these characteristic rocks preserved in Proterozoic, Archean and Hadean crust? Does a hotter mantle, higher heat production and weaker lithosphere modify or eliminate these features? What preceded subduction and how do we recognize that regime? Are rock associations or geochemical fingerprints reliable? Does reworking and overprinting modify geochemical fingerprints? Proposals for the start of plate tectonics have been based on: persistence of isotope anomalies/fractionated chemical domains in the mantle; changes in chemistry of magmatic rocks, rates of crustal growth vs reworking, and sites of growth; the metamorphic record, particularly the first appearance of contrasting thermal gradients or eclogite (including evidence from mineral inclusions in diamonds) or UHP metamorphic rocks; stabilization of cratonic lithosphere and formation of supercratons, and the beginning of the Proterozoic supercontinent cycle; the end of the flat Earth, emergence of continents, development of significant topography, changes in the style of orogeny and the rise in atmospheric oxygen; and, the appearance of passive margins and changes in the style of sedimentation. Estimates of the timing have varied from the Hadean to Neoproterozoic. I will summarize evidence for a growing consensus that the late Mesoarchean to early Paleoproterozoic was a 700 Myr long period of transition to continuous (?) subduction and global (?) mobile-lid plate tectonics.

  10. Venusian tectonics: Convective coupling to the lithosphere?

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1987-01-01

    The relationship between the dominant global heat loss mechanism and planetary size has motivated the search for tectonic style on Venus. Prior to the American and Soviet mapping missions of the past eight years, it was thought that terrestrial style plate tectonics was operative on Venus because this planet is approximately the size of the Earth and is conjectured to have about the same heat source content per unit mass. However, surface topography mapped by the altimeter of the Pioneer Venus spacecraft did not show any physiographic expression of terrestrial style spreading ridges, trenches, volcanic arcs or transform faults, although the horizontal resolution was questionable for detection of at least some of these features. The Venera 15 and 16 radar missions mapped the northern latitudes of Venus at 1 to 2 km resolution and showed that there are significant geographic areas of deformation seemingly created by large horizontal stresses. These same high resolution images show no evidence for plate tectonic features. Thus a fundamental problem for venusian tectonics is the origin of large horizontal stresses near the surface in the apparent absence of plate tectonics.

  11. Plate tectonics, habitability and life

    NASA Astrophysics Data System (ADS)

    Spohn, Tilman; Breuer, Doris

    2016-04-01

    The role of plate tectonics in defining habitability of terrestrial planets is being increasingly discussed (e.g., Elkins-Tanton, 2015). Plate tectonics is a significantly evolved concept with a large variety of aspects. In the present context, cycling of material between near surface and mantle reservoirs is most important. But increased heat transport through mixing of cold lithosphere with the deep interior and formation of continental crust may also matter. An alternative mechanism of material cycling between these reservoirs is hot-spot volcanism combined with crust delamination. Hot-spot volcanism will transport volatiles to the atmosphere while delamination will mix crust, possibly altered by sedimentation and chemical reactions, with the mantle. The mechanism works as long as the stagnant lithosphere plate has not grown thicker than the crust and as long as volcanic material is added onto the crust. Thermal evolution studies suggest that the mechanism could work for the first 1-2 Ga of planetary evolution. The efficiency of the mechanism is limited by the ratio of extrusive to intrusive volcanism, which is thought to be less than 0.25. Plate tectonics would certainly have an advantage by working even for more evolved planets. A simple, most-used concept of habitability requires the thermodynamic stability of liquid water on the surface of a planet. Cycling of CO2between the atmosphere, oceans and interior through subduction and surface volcanism is an important element of the carbonate-silicate cycle, a thermostat feedback cycle that will keep the atmosphere from entering into a runaway greenhouse. Calculations for a model Earth lacking plate tectonics but degassing CO2, N, and H2O to form a surface ocean and a secondary atmosphere (Tosi et al, 2016) suggest that liquid water can be maintained on the surface for 4.5Ga. The model planet would then qualify as habitable. It is conceivable that the CO2 buffering capability of its ocean together with silicate

  12. Tectonics of Atlantic Canada

    USGS Publications Warehouse

    Williams, H.; Dehler, S.A.; Grant, A.C.; Oakey, G.N.

    1999-01-01

    The tectonic history of Atlantic Canada is summarized according to a model of multiple ocean opening-closing cycles. The modern North Atlantic Ocean is in the opening phase of its cycle. It was preceded by an early Paleozoic lapetus Ocean whose cycle led to formation of the Appalachian Orogen. lapetus was preceded by the Neoproterozoic Uranus Ocean whose cycle led to formation of the Grenville Orogen. The phenomenon of coincident, or almost coincident orogens and modern continental margins that relate to repeated ocean opening-closing cycles is called the Accordion Effect. An understanding of the North Atlantic Ocean and its continental margins provides insights into the nature of lapetus and the evolution of the Appalachian Orogen. Likewise, an understanding of lapetus and the Appalachian Orogen raises questions about Uranus and the development of the Grenville Orogen. Modern tectonic patterns in the North Atlantic may have been determined by events that began before 1000 m.y.

  13. Earth's Decelerating Tectonic Plates

    SciTech Connect

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  14. An Update on Tectonics

    NASA Astrophysics Data System (ADS)

    Geissman, John W.; Faccenna, Claudio; Niemi, Nathan A.

    2014-10-01

    In February 1982, the first issue of Tectonics was published. In the editorial policy statement for the journal, founding editors John Dewey, Paul Tapponier, and Clark Burchfiel wrote, "The central theme of Tectonics is the mechanical and thermal evolution of the lithospheric crust and mantle and the way that this is reflected in cratons, basins and mountains from the broad regional scale to the fine scale." The editors further stated, "We expect that papers on these and related topics would emanate from a wide variety of earth science disciplines ranging from physical modeling to geological field observation." Finally, with the confidence from this incredible team of editors, they noted, "We are aiming for a very rapid review process, allowing a maximum of about 1 month between submission and notification to the author of acceptance or rejection."

  15. Tectonic connections to interior processes on Venus

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1992-01-01

    The ultimate goal of geophysical/geological exploration of Venus is to relate the present tectonic (and volcanic) state of the lithosphere to interior processes, particularly mantle convection, operating both now and in the past. The Magellan mission has provided a spectacular view of the surface, and upcoming gravity measurements, particularly if the Magellan orbit is circularized, will provide significant constraints on the state of the interior. This extended abstract focuses on several controversial issues regarding venusian tectonics and its relationship to geodynamic mechanisms in the planet's interior. The origin of highlands, coronae diapir structures, and trenches and subduction are discussed.

  16. Tectonic connections to interior processes on Venus

    NASA Astrophysics Data System (ADS)

    Phillips, R. J.

    1992-12-01

    The ultimate goal of geophysical/geological exploration of Venus is to relate the present tectonic (and volcanic) state of the lithosphere to interior processes, particularly mantle convection, operating both now and in the past. The Magellan mission has provided a spectacular view of the surface, and upcoming gravity measurements, particularly if the Magellan orbit is circularized, will provide significant constraints on the state of the interior. This extended abstract focuses on several controversial issues regarding venusian tectonics and its relationship to geodynamic mechanisms in the planet's interior. The origin of highlands, coronae diapir structures, and trenches and subduction are discussed.

  17. Tectonic Plates of China

    DTIC Science & Technology

    1977-04-01

    continental crust formed before the Sinian time. They were later more or less covered by strata of different periods , metamorphozed and folded (in case of...tectonic cycles and ten orogenic periods in the formation of the fault blocks of China. Their names and time intervals, together with the blocks formed...during each period , are listed in Table 1. The positions of the blocks are shown in Fig. 1. (3) The fault blocks are separated by fault zones. Three types

  18. Tectonics wins AAP Award

    NASA Astrophysics Data System (ADS)

    AGU's newest journal, Tectonics, won the 1983 award for excellence in journal design and production given by the Association of American Publishers, Inc. (AAP), in the eighth annual professional and scholarly publishing awards competition. Edited by John F. Dewey, the bimonthly journal is a joint publication of AGU and the European Geophysical Society. Paul E. Tapponnier is the European editor and B.C. Burchfiel is the North American editor. The journal is now in its third year of publication.

  19. Identifying active interplate and intraplate fault zones in the western Caribbean plate from seismic reflection data and the significance of the Pedro Bank fault zone in the tectonic history of the Nicaraguan Rise

    NASA Astrophysics Data System (ADS)

    Ott, B.; Mann, P.

    2015-12-01

    The offshore Nicaraguan Rise in the western Caribbean Sea is an approximately 500,000 km2 area of Precambrian to Late Cretaceous tectonic terranes that have been assembled during the Late Cretaceous formation of the Caribbean plate and include: 1) the Chortis block, a continental fragment; 2) the Great Arc of the Caribbean, a deformed Cretaceous arc, and 3) the Caribbean large igneous province formed in late Cretaceous time. Middle Eocene to Recent eastward motion of the Caribbean plate has been largely controlled by strike-slip faulting along the northern Caribbean plate boundary zone that bounds the northern margin of the Nicaraguan Rise. These faults reactivate older rift structures near the island of Jamaica and form the transtensional basins of the Honduran Borderlands near Honduras. Recent GPS studies suggest that small amount of intraplate motion within the current margin of error of GPS measurements (1-3 mm/yr) may occur within the center of the western Caribbean plate at the Pedro Bank fault zone and Hess Escarpment. This study uses a database of over 54,000 km of modern and vintage 2D seismic data, combined with earthquake data and results from previous GPS studies to define the active areas of inter- and intraplate fault zones in the western Caribbean. Intraplate deformation occurs along the 700-km-long Pedro Bank fault zone that traverses the center of the Nicaraguan Rise and reactivates the paleo suture zone between the Great Arc of the Caribbean and the Caribbean large igneous province. The Pedro Bank fault zone also drives active extension at the 200-km-long San Andres rift along the southwest margin of the Nicaraguan Rise. Influence of the Cocos Ridge indentor may be contributing to reactivation of faulting along the southwesternmost, active segment of the Hess Escarpment.

  20. Tectonically Asymmetric Earth

    NASA Astrophysics Data System (ADS)

    Doglioni, C.; Carminati, E.; Crespi, M.; Cuffaro, M.; Panza, G. F.; Riguzzi, F.

    2011-12-01

    The net rotation, or so-called W-ward drift of the lithosphere, implies a decoupling of the plates relative to the underlying asthenosphere, and a relative "E-ward" mantle flow. This polarized flow can account for a number of asymmetries. When comparing the W-directed versus the E- to NE-directed subduction zones, as a general observation, they have the subduction hinge diverging versus converging relative to the upper plate; low versus high topography and structural elevation respectively; deep versus shallow trenches and foreland basins; shallow versus deep decollement; low versus high basement involvement; high versus low heat flow and gravity anomaly; shallow versus deep asthenosphere; etc. The western limbs of rift zones have in average a deeper bathymetry, and show S-waves faster in the lithosphere and slower in the asthenosphere with respect to the eastern limb. These asymmetries can be recognized when moving along the "tectonic equator", which describes the fastest flow of plates relative to the mantle, and it undulates relative to the geographic equator, with an angle of about 30°. Shear-wave splitting alignments tend to parallel the tectonic flow, apart along the subduction zones where they become orthogonal, as a flow encountering an obstacle. The estimates of the net rotation span from 0.2° to 1.2° Ma. However, only a net rotation >1° Ma is required in order to satisfy the aforementioned tectonically asymmetric Earth. In our reconstructions, the best fit for the tectonic equator has a pole of rotation at latitude 56.4° and longitude 136.7°, with an angular velocity of 1.2036°/Ma. This velocity can be obtained only if the source of the so-called volcanic trails or plumes are sourced from the middle of the low-velocity layer, at the top of the asthenosphere, i.e., within the decoupling layer of the plates relative to the underlying mantle. The tectonic equator lies close to the revolution plane of the Moon about the Earth. All these data and

  1. The global tectonic pattern

    NASA Astrophysics Data System (ADS)

    Doglioni, Carlo

    1990-07-01

    The relative motion vectors between the lithosphere and the underlying mantle appear to follow global flow lines which can be constructed by linking axes of extension and compression over the Earth's surface. The flow lines for the last 40 Ma are generally WNW-ESE (E-W), with an undulation of an about 15,000 km wavelength, showing a gradual and progressive variation in orientation. The undulation, which is sharper to the east, may reflect the mantle flow around an unstable rotation axis. The westward motion of the lithospheric plates could be interpreted as a result of differential angular velocity induced by the deceleration of the earth's rotation or, in a toroidal field, by the effects induced by lateral heterogeneities both in the lithosphere and in the mantle. In this light, plate tectonics is a consequence of variable decoupling at the base of the lithosphere as a function of mantle anisotropies. Simply stated, when there is compression or transpression between two plates, it is the eastern plate which moves more rapidly westwards relative to the underlying mantle. If there is extension or transtension, it is the western plate that moves faster westwards. Lithospheric subduction, especially if it dips westward, produces an obstacle to the eastward flow of the mantle. This is referred to as the Nail Effect. The eastward roll-back of the subduction hinge due to the mantle push will generate back-arc extension. Subductions following the mantle flow (E or NE-dipping) are associated to thicker thrust belts with huge exposures of basement rocks in the hinterland and shallow foreland basins. The subductions contrasting the mantle flow (W or SW-dipping) are characterized by shallow thrust belts with deep foreland basin and coeval extension in the back. E-dipping subductions are passive responses to actively thrusting plates: the base plate and intra-lithospheric decollements are connected to the surface and can uplift deep rocks. The W-dipping subductions are

  2. Universal planetary tectonics (supertectonics)

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2009-04-01

    Universal planetary tectonics (supertectonics) G. Kochemasov IGEM of the Russian Academy of Sciences, Moscow, Russia, kochem.36@mail.ru The wave planetology [1-3 & others] proceeds from the following: "planetary structures are made by orbits and rotations". A uniform reason makes uniform structures. Inertia-gravity waves arising in planetary bodies due to their movements in Keplerian elliptical orbits with periodically changing accelerations warp these bodies in such way that they acquire polyhedron shapes (after interference of standing waves of four directions). Strong Newtonian gravity makes bodies larger than ~400 to 500 km in diameter globular and polyhedra are rarely seen. Only geomorphologic, geologic and geophysical mapping can develop these hidden structures. But small bodies, normally less than ~ 300 to 400 km in diameter, often show parts of the polyhedra, rarely fully developed forms (the asteroid Steins and satellite Amalthea present rather perfect forms of "diamond"). Depending on warping wavelengths (they make harmonics) various Plato's figures superimposed on each other can be distinguished. The fundamental wave 1 produces a tetrahedron, intrinsically dichotomic figure in which a vertex (contraction) always is opposed to a face (expansion). From the recent examples the best is the saturnian northern hexagon (a face) opposed to the southern hurricane (a vertex). The first overtone wave 2 is responsible for creation of structural octahedra. Whole ‘diamonds" and their parts are known [4, 5]. Other overtones produce less developed (because of smaller wave amplitudes) planetary shapes complicating main forms. Thus, the first common structural peculiarity of planetary bodies is their polyhedron nature. Not less important is the second common structural peculiarity. As all globular or smaller more or less isometric bodies rotate, they have an angular momentum. It is inevitably different in tropic and extra-tropic belts having uneven radii or distances to

  3. The history of tectonism on Venus: A stratigraphic analysis

    NASA Astrophysics Data System (ADS)

    Ivanov, Mikhail A.; Head, James W.

    2015-08-01

    The surface of Venus displays several tectonized terrains in which the morphologic characteristics of the original materials are almost completely erased by superposed tectonic structures whose large dimensions (»100 km) suggest formation related to mantle convection. The characteristics of these tectonized terrains are in contrast to volcanic units in which tectonic structures are less significant or absent and thus do not obscure the volcanic character of the units. We describe the temporal distribution of tectonized terrains, their stratigraphic relationships with volcanic units, and how these outline the major episodes in the geological evolution of Venus. Five major tectonized units make up ~20% of the planet: (1) tessera (t, 7.3%), (2) densely lineated plains (pdl, 1.6%), (3) ridged plains/ridge belts (pr/rb, 2.4%), (4) groove belts (gb, 8.1%), and (5) rift zones (rz, 5.0%). Clear relationships of relative age are often seen among the tectonic and volcanic units at the global scale and define three contrasting regimes of volcanic and tectonic resurfacing. The majority of tectonized terrains (t through gb) are the products of tectonic resurfacing and are embayed by the vast volcanic plains and, thus, are older. There are no units with either mildly- or non-tectonized surfaces that interleave the tectonic terrains, which would be expected if the tectonic resurfacing operated only during specific repetitive phases in discrete regions. These tectonized terrains (t through gb) thus define a tectonically dominated regime of resurfacing that occurred at a global-scale near the beginning of the observable geological history of Venus. This ancient tectonic regime began with formation of tessera and was followed by formation of pdl and pr/rb. Groove belts formed near the end of this regime. Branches of groove belts compose the tectonic components of many coronae, suggesting that these features are genetically related (e.g., mutual development of mantle diapirs and

  4. Tectonic resurfacing of Venus

    NASA Technical Reports Server (NTRS)

    Malin, Michael C.; Grimm, Robert E.; Herrick, Robert R.

    1993-01-01

    Impact crater distributions and morphologies have traditionally played an important role in unraveling the geologic histories of terrestrial objects, and Venus has proved no exception. The key observations are: mean crater retention age about 500 Ma; apparently random spatial distribution; modest proportion (17 percent) of modified craters; and preferential association of modified craters with areas of low crater density. The simplest interpretation of these data alone is that Venus experienced global resurfacing (assumed to be largely volcanic) prior to 500 Ma, after which time resurfacing rates decreased dramatically. This scenario does not totally exclude present geological activity: some resurfacing and crater obliteration is occurring on part of the planet, but at rates much smaller than on Earth. An alternative endmember model holds that resurfacing is also spatially randomly distributed. Resurfacing of about 1 sq km/yr eliminates craters such that a typical portion of the surface has an age of 500 Ma, but actual ages range from zero to about 1000 Ma. Monte Carlo simulation indicates that the typical resurfacing 'patch' cannot exceed about 500 km in diameter without producing a crater distribution more heterogeneous than observed. Volcanic or tectonic processes within these patches must be locally intense to be able to obliterate craters completely and leave few modified. In this abstract, we describe how global geologic mapping may be used to test resurfacing hypotheses. We present preliminary evidence that the dominant mode of resurfacing on Venus is tectonism, not volcanism, and that this process must be ongoing today. Lastly, we outline a conceptual model in which to understand the relationship between global tectonics and crater distribution and preservation.

  5. Complex Tectonism on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Complex tectonism is evident in these images of Ganymede's surface. The solid state imaging camera on NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. The 80 kilometer (50 mile) wide lens-shaped feature in the center of the image is located at 32 degrees latitude and 188 degrees longitude along the border of a region of ancient dark terrain known as Marius Regio, and is near an area of younger bright terrain named Nippur Sulcus. The tectonism that created the structures in the bright terrain nearby has strongly affected the local dark terrain to form unusual structures such as the one shown here. The lens-like appearance of this feature is probably due to shearing of the surface, where areas have slid past each other and also rotated slightly. Note that in several places in these images, especially around the border of the lens-shaped feature, bright ridges appear to turn into dark grooves. Analysis of the geologic structures in areas like this are helping scientists to understand the complex tectonic history of Ganymede.

    North is to the top-left of the image, and the sun illuminates the surface from the southeast. The image covers an area about 63 kilometers (39 miles) by 120 kilometers (75 miles) across at a resolution of 188 meters (627 feet) per picture element. The images were taken on September 6, 1996 at a range of 18,522 kilometers (11,576 miles) by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  6. Retrospective salt tectonics

    SciTech Connect

    Jackson, M.P.A.

    1996-12-31

    The conceptual breakthroughs in understanding salt tectonics can be recognized by reviewing the history of salt tectonics, which divides naturally into three parts: the pioneering era, the fluid era, and the brittle era. The pioneering era (1856-1933) featured the search for a general hypothesis of salt diapirism, initially dominated by bizarre, erroneous notions of igneous activity, residual islands, in situ crystallization, osmotic pressures, and expansive crystallization. Gradually data from oil exploration constrained speculation. The effects of buoyancy versus orogeny were debated, contact relations were characterized, salt glaciers were discovered, and the concepts of downbuilding and differential loading were proposed as diapiric mechanisms. The fluid era (1933-{approximately}1989) was dominated by the view that salt tectonics resulted from Rayleigh-Taylor instabilities in which a dense fluid overburden having negligible yield strength sinks into a less dense fluid salt layer, displacing it upward. Density contrasts, viscosity contrasts, and dominant wavelengths were emphasized, whereas strength and faulting of the overburden were ignored. During this era, palinspastic reconstructions were attempted; salt upwelling below thin overburdens was recognized; internal structures of mined diapirs were discovered; peripheral sinks, turtle structures, and diapir families were comprehended; flow laws for dry salt were formulated; and contractional belts on divergent margins and allochthonous salt sheets were recognized. The 1970s revealed the basic driving force of salt allochthons, intrasalt minibasins, finite strains in diapirs, the possibility of thermal convection in salt, direct measurement of salt glacial flow stimulated by rainfall, and the internal structure of convecting evaporites and salt glaciers. The 1980`s revealed salt rollers, subtle traps, flow laws for damp salt, salt canopies, and mushroom diapirs.

  7. Complex Tectonism on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Complex tectonism is evident in these images of Ganymede's surface. The solid state imaging camera on NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. The 80 kilometer (50 mile) wide lens-shaped feature in the center of the image is located at 32 degrees latitude and 188 degrees longitude along the border of a region of ancient dark terrain known as Marius Regio, and is near an area of younger bright terrain named Nippur Sulcus. The tectonism that created the structures in the bright terrain nearby has strongly affected the local dark terrain to form unusual structures such as the one shown here. The lens-like appearance of this feature is probably due to shearing of the surface, where areas have slid past each other and also rotated slightly. Note that in several places in these images, especially around the border of the lens-shaped feature, bright ridges appear to turn into dark grooves. Analysis of the geologic structures in areas like this are helping scientists to understand the complex tectonic history of Ganymede.

    North is to the top-left of the image, and the sun illuminates the surface from the southeast. The image covers an area about 63 kilometers (39 miles) by 120 kilometers (75 miles) across at a resolution of 188 meters (627 feet) per picture element. The images were taken on September 6, 1996 at a range of 18,522 kilometers (11,576 miles) by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  8. Martian plate tectonics

    NASA Astrophysics Data System (ADS)

    Sleep, N. H.

    1994-03-01

    The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses

  9. Mars tectonics and volcanism

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1990-01-01

    The focus of this research was on three broad areas: (1) the relation between lithospheric stress in the vicinity of a growing volcano and the evolution of eruption characteristics and tectonic faulting; (2) the relation between elastic lithosphere thickness and thermal structure; and (3) a synthesis of constraints on heat flow and internal dynamics on Mars. The two reports presented are: (1) Heterogeneities in the Thickness of the Elastic Lithosphere of Mars--Constraints on Heat Flow and Internal Dynamics; and (2) State of Stress, Faulting, and Eruption Characteristics of Large Volcanoes on Mars.

  10. Quarternary tectonics, Task 1

    SciTech Connect

    Bell, J.W.

    1993-09-30

    Activities conducted for the evaluation of the geology and seismotectonics stability of Yucca Mountain as a potential site for the underground disposal of high-level radioactive wastes continued. Tasks concerned with quaternary tectonics include: scheduling of photography of Little Skull Mountain area; the collection and dating of rock varnish samples from the 1932 Cedar Mountain earthquake area for carbon 14 AMS and cation-ratio analysis; collection of samples for thermoluminescence dating from the 1932 Cedar Mountain earthquake area; mapping of the northern area of Crater Flat; and surveying of the May 17, 1993 Eureka the Valley earthquake area.

  11. Tectonic discrimination diagrams revisited

    NASA Astrophysics Data System (ADS)

    Vermeesch, Pieter

    2006-06-01

    The decision boundaries of most tectonic discrimination diagrams are drawn by eye. Discriminant analysis is a statistically more rigorous way to determine the tectonic affinity of oceanic basalts based on their bulk-rock chemistry. This method was applied to a database of 756 oceanic basalts of known tectonic affinity (ocean island, mid-ocean ridge, or island arc). For each of these training data, up to 45 major, minor, and trace elements were measured. Discriminant analysis assumes multivariate normality. If the same covariance structure is shared by all the classes (i.e., tectonic affinities), the decision boundaries are linear, hence the term linear discriminant analysis (LDA). In contrast with this, quadratic discriminant analysis (QDA) allows the classes to have different covariance structures. To solve the statistical problems associated with the constant-sum constraint of geochemical data, the training data must be transformed to log-ratio space before performing a discriminant analysis. The results can be mapped back to the compositional data space using the inverse log-ratio transformation. An exhaustive exploration of 14,190 possible ternary discrimination diagrams yields the Ti-Si-Sr system as the best linear discrimination diagram and the Na-Nb-Sr system as the best quadratic discrimination diagram. The best linear and quadratic discrimination diagrams using only immobile elements are Ti-V-Sc and Ti-V-Sm, respectively. As little as 5% of the training data are misclassified by these discrimination diagrams. Testing them on a second database of 182 samples that were not part of the training data yields a more reliable estimate of future performance. Although QDA misclassifies fewer training data than LDA, the opposite is generally true for the test data. Therefore LDA is a cruder but more robust classifier than QDA. Another advantage of LDA is that it provides a powerful way to reduce the dimensionality of the multivariate geochemical data in a similar

  12. Korea's School Grounds Projects

    ERIC Educational Resources Information Center

    Park, Joohun

    2003-01-01

    This article describes two projects which Korea has undertaken to improve its school grounds: (1) the Green School Project; and (2) the School Forest Pilot Project. The Korean Ministry of Education and Human Resources Development (MOE&HRI) recently launched the Green School Project centred on existing urban schools with poor outdoor…

  13. Dance Education in Korea

    ERIC Educational Resources Information Center

    Byeon, Jae-Kyung

    2012-01-01

    Despite a structured physical education system and related policies, dance education in Korea largely exists as a course in name only, without achieving its unique goals. It lacks standards within the physical education curriculum, which indicates that dance education is not conducted properly. Thus, the content and level of dance education vary…

  14. Divided Korea: United Future?

    ERIC Educational Resources Information Center

    Cumings, Bruce

    1995-01-01

    Korea's recorded history extends back before the birth of Christ. Through their long history, the Koreans have endured a variety of social, political, and economical crises. Confucianism has long been one of the most popular religions by which the Korean people have lived. However, Koreans also have embraced Buddhism and Christianity while…

  15. Educational Facilities in Korea.

    ERIC Educational Resources Information Center

    PEB Exchange, 1999

    1999-01-01

    Describes a Korean program to modernize school buildings and equipment to better meet current teaching needs.Examines Korea's education and administrative systems, and the Ministry of Education's involvement in schooling trends, facilities for higher education, and developments in information and technology. (GR)

  16. Korea's School Grounds Projects

    ERIC Educational Resources Information Center

    Park, Joohun

    2003-01-01

    This article describes two projects which Korea has undertaken to improve its school grounds: (1) the Green School Project; and (2) the School Forest Pilot Project. The Korean Ministry of Education and Human Resources Development (MOE&HRI) recently launched the Green School Project centred on existing urban schools with poor outdoor…

  17. Tectonic stress - Models and magnitudes

    NASA Technical Reports Server (NTRS)

    Solomon, S. C.; Bergman, E. A.; Richardson, R. M.

    1980-01-01

    It is shown that global data on directions of principal stresses in plate interiors can serve as a test of possible plate tectonic force models. Such tests performed to date favor force models in which ridge pushing forces play a significant role. For such models the general magnitude of regional deviatoric stresses is comparable to the 200-300 bar compressive stress exerted by spreading ridges. An alternative approach to estimating magnitudes of regional deviatoric stresses from stress orientations is to seek regions of local stress either demonstrably smaller than or larger than the regional stresses. The regional stresses in oceanic intraplate regions are larger than the 100-bar compression exerted by the Ninetyeast Ridge and less than the bending stresses (not less than 1 kbar) beneath Hawaii.

  18. Earthquakes and plate tectonics.

    USGS Publications Warehouse

    Spall, H.

    1982-01-01

    Earthquakes occur at the following three kinds of plate boundary: ocean ridges where the plates are pulled apart, margins where the plates scrape past one another, and margins where one plate is thrust under the other. Thus, we can predict the general regions on the earth's surface where we can expect large earthquakes in the future. We know that each year about 140 earthquakes of magnitude 6 or greater will occur within this area which is 10% of the earth's surface. But on a worldwide basis we cannot say with much accuracy when these events will occur. The reason is that the processes in plate tectonics have been going on for millions of years. Averaged over this interval, plate motions amount to several mm per year. But at any instant in geologic time, for example the year 1982, we do not know, exactly where we are in the worldwide cycle of strain build-up and strain release. Only by monitoring the stress and strain in small areas, for instance, the San Andreas fault, in great detail can we hope to predict when renewed activity in that part of the plate tectonics arena is likely to take place. -from Author

  19. Intermittent plate tectonics?

    PubMed

    Silver, Paul G; Behn, Mark D

    2008-01-04

    Although it is commonly assumed that subduction has operated continuously on Earth without interruption, subduction zones are routinely terminated by ocean closure and supercontinent assembly. Under certain circumstances, this could lead to a dramatic loss of subduction, globally. Closure of a Pacific-type basin, for example, would eliminate most subduction, unless this loss were compensated for by comparable subduction initiation elsewhere. Given the evidence for Pacific-type closure in Earth's past, the absence of a direct mechanism for termination/initiation compensation, and recent data supporting a minimum in subduction flux in the Mesoproterozoic, we hypothesize that dramatic reductions or temporary cessations of subduction have occurred in Earth's history. Such deviations in the continuity of plate tectonics have important consequences for Earth's thermal and continental evolution.

  20. River history and tectonics.

    PubMed

    Vita-Finzi, C

    2012-05-13

    The analysis of crustal deformation by tectonic processes has gained much from the clues offered by drainage geometry and river behaviour, while the interpretation of channel patterns and sequences benefits from information on Earth movements before or during their development. The interplay between the two strands operates at many scales: themes which have already benefited from it include the possible role of mantle plumes in the breakup of Gondwana, the Cenozoic development of drainage systems in Africa and Australia, Himalayan uplift in response to erosion, alternating episodes of uplift and subsidence in the Mississippi delta, buckling of the Indian lithospheric plate, and changes in stream pattern and sinuosity along individual alluvial channels subject to localized deformation. Developments in remote sensing, isotopic dating and numerical modelling are starting to yield quantitative analyses of such effects, to the benefit of geodymamics as well as fluvial hydrology. This journal is © 2012 The Royal Society

  1. Astrophysical Cause of Tectonics

    NASA Astrophysics Data System (ADS)

    Mensur, O.

    2016-05-01

    Tectonic earthquakes, of Mw (6 ± 5%)+, are found forming a strengthening-peaking-waning pattern distinguishable from respectively quiescent times so well that the pattern means discovery of a universal natural mechanism that necessitates expanding on classical physics. The pattern is seen only during Earth's alignments to two other heavenly bodies in our solar system lasting for more than 3 days. This empirical proof of astrophysical origins of seismotectonics is immediately obvious and verifiable. The find is consequential due to sheer size of processes and energies involved in defining the pattern that now enables all-or-nothing negative forecasting by foretelling dates without strong quakes. Near co-planarity of a solar system's planets, which is for our solar system typically regarded an oddity, is in fact a necessary condition for active geophysics as a life system.

  2. Plate Tectonics: A Paradigm under Threat.

    ERIC Educational Resources Information Center

    Pratt, David

    2000-01-01

    Discusses the challenges confronting plate tectonics. Presents evidence that contradicts continental drift, seafloor spreading, and subduction. Reviews problems posed by vertical tectonic movements. (Contains 242 references.) (DDR)

  3. Plate Tectonics: A Paradigm under Threat.

    ERIC Educational Resources Information Center

    Pratt, David

    2000-01-01

    Discusses the challenges confronting plate tectonics. Presents evidence that contradicts continental drift, seafloor spreading, and subduction. Reviews problems posed by vertical tectonic movements. (Contains 242 references.) (DDR)

  4. Tectonics and metallogenic provinces

    USGS Publications Warehouse

    Guild, P.W.

    1983-01-01

    Various theories have been advanced to explain the well-known uneven distribution of metals and ore-deposit types in space and time. Primordial differences in the mantle, preferential concentration of elements in the crust, the prevalence of ore-forming processes at certain times and (or) places, and combinations of one or several of these factors have all been called upon to account for the "metallogenic provinces," which can be defined loosely as regions containing similar deposits of one or a group of metals or minerals. Because many, perhaps most, provinces have complex, multistage origins, the relative importance of inheritance vs. process is still controversial. In recent years the geographic relationship of many geologically young provinces to present-day plate-tectonic positions (accreting or consuming margins, intraplate structures, etc.) has been widely recognized, and the presumption is strong that older provinces had similar relationships to former plates. As most ore deposits resulted from a favorable conjunction of geological processes that are no longer operative, elucidation of their genesis requires reconstruction of the geologic history of the province, with particular emphasis on events coeval with mineralization. Tectonic analysis is an important aspect of this reconstruction; data from orbiting satellites have contributed greatly to this analysis, as the voluminous literature of the past decade testifies. Both the synoptic view of large areas and the ability to emphasize faint contrasts have revealed linear, curvilinear, and circular features not previously recognized from field studies. Some of these undoubtedly reflect basement structures that have contributed to the development, or limit the extent, of metallogenic provinces. Their recognition and delineation will be increasingly valuable to the assessment of resources available and as guides to exploration for the ores needed by future generations. ?? 1983.

  5. A tectonic resurfacing model for Venus

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1993-01-01

    Two remarkable aspects of the population of impact craters on Venus are that craters at all sizes are indistinguishable from a random population and that the vast majority of craters have not been significantly modified by tectonic strain or by volcanic flows external to the crater rim, despite evidence from Magellan images that volcanic and tectonic features are widespread on Venus. One interpretation of these observations is that most of the surface dates from the end of a catastrophic global resurfacing event that ceased about 500 My ago, and that the small fraction of craters volcanically embayed or modified by deformation indicates that volcanic and tectonic activity subsequent to that time has been at much lower levels. An alternative model, in which resurfacing occurs episodically in patches a few hundred kilometers in extent and there is a wider spectrum of surface ages, also appears to be consistent with the characteristics of impact craters on Venus. A number of potential mechanisms for catastrophic resurfacing of Venus have been proposed, ranging from geologically sudden convective destabilization of the global lithosphere to strongly time-dependent heat flux and melt generation in the underlying mantle. In most of these geophysical models, resurfacing occurs implicitly or explicitly by volcanism. We explore the hypothesis that, at least in the geologically recent history of Venus, the primary resurfacing mechanism has been tectonic deformation rather than volcanism. We show how such a hypothesis provides at least as good an explanation of a wide range of observations as do volcanic resurfacing models. Finally, we explore the implications of tectonic resurfacing hypothesis for the controversy over the recent resurfacing history of the planet.

  6. A tectonic resurfacing model for Venus

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1993-01-01

    Two remarkable aspects of the population of impact craters on Venus are as follows: that craters at all sizes are indistinguishable from a random population; and that the vast majority of craters have not been significantly modified by tectonic strain or by volcanic flows external to the crater rim, despite evidence from Magellan images that volcanic and tectonic features are widespread on Venus. One interpretation of these observations is that most of the surface dates from the end of a catastrophic global resurfacing event that ceased about 500 My ago, and that the small fraction of craters volcanically embayed or modified by deformation indicates that volcanic and tectonic activity subsequent to that time has been at much lower levels. An alternative model, in which resurfacing occurs episodically in patches a few hundred kilometers in extent and there is a wider spectrum of surface ages, also appears to be consistent with the characteristics of impact craters on Venus. A number of potential mechanisms for catastrophic resurfacing of Venus have been proposed ranging from geologically sudden convective destabilization of the global lithosphere to strongly time-dependent heat flux and melt generation in the underlying mantle. In most of these geophysical models, resurfacing occurs implicitly or explicitly by volcanism. We explore here the hypothesis that, at least in the geologically recent history of Venus, the primary resurfacing mechanism has been tectonic deformation rather than volcanism. We show how such a hypothesis provides at least as good an explanation of a wide range of observations as do volcanic resurfacing models. Finally, we explore the implications of the tectonic resurfacing hypothesis for the controversy over the recent resurfacing history of the planet.

  7. Prediction of Cancer Incidence and Mortality in Korea, 2017.

    PubMed

    Jung, Kyu-Won; Won, Young-Joo; Oh, Chang-Mo; Kong, Hyun-Joo; Lee, Duk Hyoung; Lee, Kang Hyun

    2017-04-01

    This study aimed to report on cancer incidence and mortality for the year 2017 in Korea in order to estimate the nation's current cancer burden. Cancer incidence data from 1999 to 2014 were obtained from the Korea National Cancer Incidence Database, and cancer mortality data from 1993 to 2015 were acquired from Statistics Korea. Cancer incidence and mortality were projected by fitting a linear regression model to observe age-specific cancer rates against observed years, and then multiplying the projected age-specific rates by the age-specific population. The Joinpoint regression model was used to determine at which year the linear trend changed significantly; we only used data of the latest trend. A total of 221,143 new cancer cases and 80,268 cancer deaths are expected to occur in Korea in 2017. The most common cancer sites are the colorectum, stomach, lung, thyroid, and breast. These five cancers represent half of the overall burden of cancer in Korea. For mortality, the most common sites are the lung, liver, colorectal, stomach, and pancreas. The incidence rate of all cancers in Korea appears to have decreased mainly because of a decrease in thyroid cancer. These up-to-date estimates of the cancer burden in Korea could be an important resource for planning and evaluation of cancer-control programs.

  8. Prediction of Cancer Incidence and Mortality in Korea, 2017

    PubMed Central

    Jung, Kyu-Won; Won, Young-Joo; Oh, Chang-Mo; Kong, Hyun-Joo; Lee, Duk Hyoung; Lee, Kang Hyun

    2017-01-01

    Purpose This study aimed to report on cancer incidence and mortality for the year 2017 in Korea in order to estimate the nation’s current cancer burden. Materials and Methods Cancer incidence data from 1999 to 2014 were obtained from the Korea National Cancer Incidence Database, and cancer mortality data from 1993 to 2015 were acquired from Statistics Korea. Cancer incidence and mortality were projected by fitting a linear regression model to observe age-specific cancer rates against observed years, and then multiplying the projected age-specific rates by the age-specific population. The Joinpoint regression model was used to determine at which year the linear trend changed significantly; we only used data of the latest trend. Results A total of 221,143 new cancer cases and 80,268 cancer deaths are expected to occur in Korea in 2017. The most common cancer sites are the colorectum, stomach, lung, thyroid, and breast. These five cancers represent half of the overall burden of cancer in Korea. For mortality, the most common sites are the lung, liver, colorectal, stomach, and pancreas. Conclusion The incidence rate of all cancers in Korea appears to have decreased mainly because of a decrease in thyroid cancer. These up-to-date estimates of the cancer burden in Korea could be an important resource for planning and evaluation of cancer-control programs. PMID:28301926

  9. East Asia: Korea.

    DTIC Science & Technology

    1988-07-18

    CHOSON Reviews Korean Army 13 ECONOMIC Samsung Group Moves Toward Merger, Expansion 34 Production of Export Goods Diversified 35 Rapid Information...events and the income from the sale of TV broadcasting privileges." However, the IOC and the Korean Olympic Committee (KOC) of Seoul have taken the...explanation into rumors that 6.5 million U.S. dollars was received as a commis- sion for Korea’s purchase of u.s. weapons during the Chon government, as

  10. South Korea Leads the Warfight

    DTIC Science & Technology

    2007-01-01

    warfighting command in a doctrinally supporting relationship to the ROK armed forces. The evolution to a Korean -led defense of the Republic of Korea is a...T he Republic of Korea –U.S. alliance is embarking on the most profound transformation affecting American forces on the peninsula since the Korean ...War. For the last 57 years, the United States has led the war- fighting command responsible for the defense of the Republic of Korea (ROK). As the ROK

  11. Greenstone belt tectonics: Thermal constraints

    NASA Technical Reports Server (NTRS)

    Bickle, M. J.; Nisbet, E. G.

    1986-01-01

    Archaean rocks provide a record of the early stages of planetary evolution. The interpretation is frustrated by the probable unrepresentative nature of the preserved crust and by the well known ambiguities of tectonic geological synthesis. Broad constraints can be placed on the tectonic processes in the early Earth from global scale modeling of thermal and chemical evolution of the Earth and its hydrosphere and atmosphere. The Archean record is the main test of such models. Available general model constraints are outlined based on the global tectonic setting within which Archaean crust evolved and on the direct evidence the Archaean record provides, particularly the thermal state of the early Earth.

  12. Continental tectonics in the aftermath of plate tectonics

    NASA Technical Reports Server (NTRS)

    Molnar, Peter

    1988-01-01

    It is shown that the basic tenet of plate tectonics, rigid-body movements of large plates of lithosphere, fails to apply to continental interiors. There, buoyant continental crust can detach from the underlying mantle to form mountain ranges and broad zones of diffuse tectonic activity. The role of crustal blocks and of the detachment of crustal fragments in this process is discussed. Future areas of investigation are addressed.

  13. Continental tectonics in the aftermath of plate tectonics

    NASA Technical Reports Server (NTRS)

    Molnar, Peter

    1988-01-01

    It is shown that the basic tenet of plate tectonics, rigid-body movements of large plates of lithosphere, fails to apply to continental interiors. There, buoyant continental crust can detach from the underlying mantle to form mountain ranges and broad zones of diffuse tectonic activity. The role of crustal blocks and of the detachment of crustal fragments in this process is discussed. Future areas of investigation are addressed.

  14. Tectonic Terminology: Some Proposed Changes

    ERIC Educational Resources Information Center

    Hill, Mason L.

    1978-01-01

    Plate tectonics concepts require a definition of fault, a new term to compliment epeirogeny, and a clarification of transform fault characteristics. This article makes proposals for these changes. (Author/MA)

  15. Tectonics: Changing of the plates

    NASA Astrophysics Data System (ADS)

    Brandon, Alan

    2016-10-01

    The composition of Earth's crust depends on the style of plate tectonics and of the melting regimes in the mantle. Analyses of the oldest identified rocks suggest that these styles and the resulting crust have changed over Earth's history.

  16. Tectonic Terminology: Some Proposed Changes

    ERIC Educational Resources Information Center

    Hill, Mason L.

    1978-01-01

    Plate tectonics concepts require a definition of fault, a new term to compliment epeirogeny, and a clarification of transform fault characteristics. This article makes proposals for these changes. (Author/MA)

  17. Jadeitites and Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Harlow, George E.; Tsujimori, Tatsuki; Sorensen, Sorena S.

    2015-05-01

    Jadeitite is a relatively rare, very tough rock composed predominantly of jadeite and typically found associated with tectonic blocks of high-pressure/low-temperature metabasaltic rocks (e.g., eclogite, blueschist) in exhumed serpentinite-matrix mélanges. Studies over the past ˜20 years have interpreted jadeitite either as the direct hydrous fluid precipitate from subduction channel dewatering into the overlying mantle wedge or as the metasomatic replacement by such fluids of oceanic plagiogranite, graywacke, or metabasite along the channel margin. Thus, jadeitites directly sample and record fluid transport in the subduction factory and provide a window into this geochemical process that is critical to a major process in the Earth system. They record the remarkable transport of large ion lithophile elements, such as Li, Ba, Sr, and Pb, as well as elements generally considered more refractory, such as U, Th, Zr, and Hf. Jadeitite is also the precious form of jade, utilized since antiquity in the form of tools, adornments, and symbols of prestige.

  18. Salt tectonics on Venus

    SciTech Connect

    Wood, C.A.; Amsbury, D.

    1986-05-01

    The discovery of a surprisingly high deuterium/hydrogen ratio on Venus immediately led to the speculation that Venus may have once had a volume of surface water comparable to that of the terrestrial oceans. The authors propose that the evaporation of this putative ocean may have yielded residual salt deposits that formed various terrain features depicted in Venera 15 and 16 radar images. By analogy with models for the total evaporation of the terrestrial oceans, evaporite deposits on Venus should be at least tens to hundreds of meters thick. From photogeologic evidence and in-situ chemical analyses, it appears that the salt plains were later buried by lava flows. On Earth, salt diapirism leads to the formation of salt domes, anticlines, and elongated salt intrusions - features having dimensions of roughly 1 to 100 km. Due to the rapid erosion of salt by water, surface evaporite landforms are only common in dry regions such as the Zagros Mountains of Iran, where salt plugs and glaciers exist. Venus is far drier than Iran; extruded salt should be preserved, although the high surface temperature (470/sup 0/C) would probably stimulate rapid salt flow. Venus possesses a variety of circular landforms, tens to hundreds of kilometers wide, which could be either megasalt domes or salt intrusions colonizing impact craters. Additionally, arcurate bands seen in the Maxwell area of Venus could be salt intrusions formed in a region of tectonic stress. These large structures may not be salt features; nonetheless, salt features should exist on Venus.

  19. Fires and smoke in Korea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Moderate resolution Imaging Spectroradiometer (MODIS) on the Terra satellite detected several fires burning in South Korea on June 6, 2002. The smoke is blanketing both South and North Korea, and may be mingling with smoke from other fires in China. Beneath the haze, colored water at the southern tip of the Peninsula suggests sediment or phytoplankton in the coastal waters.

  20. Fires and smoke in Korea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Moderate resolution Imaging Spectroradiometer (MODIS) on the Terra satellite detected several fires burning in South Korea on June 6, 2002. The smoke is blanketing both South and North Korea, and may be mingling with smoke from other fires in China. Beneath the haze, colored water at the southern tip of the Peninsula suggests sediment or phytoplankton in the coastal waters.

  1. North Korea: A Geographical Analysis.

    ERIC Educational Resources Information Center

    Palka, Eugene J., Ed.; Galgano, Francis A., Ed.

    North Korea is a country about the size of the state of New York, inhabited by about 23 million people. It came into existence after the conclusion of World War II following decades of occupation of the Korean Peninsula by the Japanese empire. Dividing the peninsula into North and South Korea was the politically expedient solution to one of the…

  2. Tectonics of the central Andes

    NASA Technical Reports Server (NTRS)

    Bloom, Arthur L.; Isacks, Bryan L.; Fielding, Eric J.; Fox, Andrew N.; Gubbels, Timothy L.

    1989-01-01

    Acquisition of nearly complete coverage of Thematic Mapper data for the central Andes between about 15 to 34 degrees S has stimulated a comprehensive and unprecedented study of the interaction of tectonics and climate in a young and actively developing major continental mountain belt. The current state of the synoptic mapping of key physiographic, tectonic, and climatic indicators of the dynamics of the mountain/climate system are briefly reviewed.

  3. Embayment in Tectonized Fluvial Terrain

    NASA Image and Video Library

    2015-04-22

    This highly tectonized terrain meaning it possesses many faults, as seen by NASA Mars Reconnaissance Orbiter, has its low-lying areas filled with some form of younger material. This particular fill is what geologists call "embayment." This observation helps scientists unravel the relative timing of the emplacement of the younger material and the numerous tectonic faults that run through this area. http://photojournal.jpl.nasa.gov/catalog/PIA19365

  4. North Korea Drought

    NASA Image and Video Library

    2015-06-29

    North Korea's state news agency reported the country is facing its worst drought in a century. Rice-growing provinces have been badly affected and more than 30% of rice paddies were parching up. A Landsat 7 image from June 29, 2002, compared with an ASTER image from June 26, 2015, shows the disparity in the rice crop. The images display vegetation in red, and bare fields in dark blue. The images cover an area of 27 x 34.5 km, and are located at 38.5 degrees north, 125.6 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA19501

  5. Improvement of APHRODITE precipitation data over South Korea

    NASA Astrophysics Data System (ADS)

    Lee, Gil; Cha, Dong-Hyun; Park, Chang-yong

    2017-04-01

    The APHRODITE (Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation of water resources) data has been widely used for the evaluation of the numerical model due to its higher spatial and temporal resolutions. However, some studies have indicated that it significantly underestimates the extreme precipitation values for several regions compared with station-based observation. In this study, therefore, the 25 year (1981-2005) APHRODITE precipitation data over South Korea was revised using Automated Synoptic Observing System (ASOS) data from Korea Meteorological Administration (KMA). After the spatial resolution and temporal interval of the ASOS data were changed to be same as those in the APHRODITE data, the GEV (Generalized Extreme Value) distribution for each data was calculated. After then, the GEV distribution of the APHRODITE data was corrected using the quantile mapping method. The corrected APHRODITE data was similar to the annual mean precipitation of the ASOS data. In particular, the annual mean precipitation over South Korea reasonably increased by 10% and the extreme value of precipitation have significantly improved. Acknowledgement The research was supported by the Korea Meteorological Administration Research and Development program under grant KMIPA 2015-2083 and the National Research Foundation of Korea Grant funded by the Ministry of Science, ICT and Future Planning of Korea (NRF-2016M3C4A7952637) for its support and assistant in completion of the study.

  6. Planetary Geophysics and Tectonics

    NASA Technical Reports Server (NTRS)

    Parmentier, E. M.

    1997-01-01

    Research supported by grant NAGW-1928 has addressed a variety of problems related to planetary evolution. One important focus has been on questions related to the role of chemical buoyancy in planetary evolution with application to both Venus and the Moon. We have developed a model for the evolution of the Moon (Hess and Parmentier, 1995) in which dense, highly radioactive, late stage magma ocean cumulates sink forming a core. This core heats the overlying, chemically layered mantle giving rise to a heated, chemically well-mixed layer that thickens with time. This Mixed layer eventually becomes hot enough and thick enough that its top begins to melt at a pressure low enough that melt is buoyant, thus creating mare basalts from a high pressure source of the correct composition and at an appropriate time in lunar evolution. In work completed during the last year, numerical experiments on convection in a chemically stably stratified fluid layer heated from below have been completed. These results show us how to calculate the evolution of a mixed layer in the Moon, depending on the heat production in the ilmenite- cumulate core and the chemical stratification of the overlying mantle. Chemical stratification of the mantle after its initial differentiation is would trap heat in the deep interior and prevent the rapid rise of plumes with accompanying volcanism. This trapping of heat in the interior can explain the thickness of the lunar lithosphere as a function of time as well as the magmatic evolution. We show that heat transported to the base of the lithosphere at a rate determined by current estimates of radioactivity in the Moon would not satisfy constraints on elastic lithosphere thickness from tectonic feature associated with basin loading. Trapping heat at depth by a chemically stratified mantle may also explain the absence of global compressional features on the surface that previous models predict for an initially hot lunar interior. For Venus, we developed a

  7. Fractal Tectonics and Erosion

    NASA Astrophysics Data System (ADS)

    Turcotte, Donald L.

    Tectonic processes build landforms that are subsequently destroyed by erosional processes. Landforms exhibit fractal statistics in a variety of ways; examples include (1) lengths of coast lines; (2) number-size statistics of lakes and islands; (3) spectral behavior of topography and bathymetry both globally and locally; and (4) branching statistics of drainage networks. Erosional processes are dominant in the development of many landforms on this planet, but similar fractal statistics are also applicable to the surface of Venus where minimal erosion has occurred. A number of dynamical systems models for landforms have been proposed, including (1) cellular automata; (2) diffusion limited aggregation; (3) self-avoiding percolation; and (4) advective-diffusion equations. The fractal statistics and validity of these models will be discussed. Earthquakes also exhibit fractal statistics. The frequency-magnitude statistics of earthquakes satisfy the fractal Gutenberg-Richter relation both globally and locally. Earthquakes are believed to be a classic example of self-organized criticality. One model for earthquakes utilizes interacting slider-blocks. These slider block models have been shown to behave chaotically and to exhibit self-organized criticality. The applicability of these models will be discussed and alternative approaches will be presented. Fragmentation has been demonstrated to produce fractal statistics in many cases. Comminution is one model for fragmentation that yields fractal statistics. It has been proposed that comminution is also responsible for much of the deformation in the earth's crust. The brittle disruption of the crust and the resulting earthquakes present an integrated problem with many fractal aspects.

  8. Planetary Geophysics and Tectonics

    NASA Technical Reports Server (NTRS)

    Zuber, Maria

    2005-01-01

    The broad objective of this work is to improve understanding of the internal structures and thermal and stress histories of the solid planets by combining results from analytical and computational modeling, and geophysical data analysis of gravity, topography and tectonic surface structures. During the past year we performed two quite independent studies in the attempt to explain the Mariner 10 magnetic observations of Mercury. In the first we revisited the possibility of crustal remanence by studying the conditions under which one could break symmetry inherent in Runcorn's model of a uniformly magnetized shell to produce a remanent signal with a dipolar form. In the second we applied a thin shell dynamo model to evaluate the range of intensity/structure for which such a planetary configuration can produce a dipole field consistent with Mariner 10 results. In the next full proposal cycle we will: (1) develop numerical and analytical and models of thin shell dynamos to address the possible nature of Mercury s present-day magnetic field and the demise of Mars magnetic field; (2) study the effect of degree-1 mantle convection on a core dynamo as relevant to the early magnetic field of Mars; (3) develop models of how the deep mantles of terrestrial planets are perturbed by large impacts and address the consequences for mantle evolution; (4) study the structure, compensation, state of stress, and viscous relaxation of lunar basins, and address implications for the Moon s state of stress and thermal history by modeling and gravity/topography analysis; and (5) use a three-dimensional viscous relaxation model for a planet with generalized vertical viscosity distribution to study the degree-two components of the Moon's topography and gravity fields to constrain the primordial stress state and spatial heterogeneity of the crust and mantle.

  9. Tectonic setting of kimberlites

    NASA Astrophysics Data System (ADS)

    Jelsma, Hielke; Barnett, Wayne; Richards, Simon; Lister, Gordon

    2009-11-01

    Kimberlites can be viewed as time capsules in a global plate tectonic framework. Their distribution illustrates clustering in time and space. Kimberlite ages span the assembly and break-up of a number of supercontinents, such as Rodinia and Gondwana. These supercontinents show time lines with (i) broad periods devoid of kimberlite magmatism corresponding to times of continent stability, and (ii) narrow kimberlite emplacement windows corresponding to times of fundamental plate reorganizations. This episodicity implies that kimberlite emplacement events are intrinsically related to particular stages in the life cycle of supercontinents. The onset of kimberlite magmatism is closely associated with thermal perturbations (thermal insulation, mantle upwelling?) beneath a stagnant or sluggish supercontinent. These perturbations may have caused uplift and the onset of continental break-up through fracture zones propagating into the supercontinent. Subsequent spreading and ocean floor development is marked by apparent cusps and jogs in plate motion paths. Resultant strain is accommodated along trans-lithospheric corridors with episodic uplift and erosion and focused kimberlite melt migration. The corridors are manifest as discontinuities in the lithosphere mantle, measured as geophysical gradients and as changes in mantle lithosphere composition. Within the crust, these corridors are expressed as (a) terrane boundaries, (b) incipient continental rifts, (c) fracture zones, or (d) major dyke swarms. Some kimberlite populations are clustered along parallel sets of corridors widely distributed across a large part of a subcontinent and repeated magmatism is seen within many of the clusters. The association of kimberlite occurrences with discontinuities may be ascribed to favorable conditions for melt production and to resultant melt focusing along high strain zones that contain fractures and faults. Such conditions may be attained during different stages in the evolution of

  10. Preliminary GPS results and a possible neotectonic interpretation for South Korea

    NASA Astrophysics Data System (ADS)

    Park, P.-H.; Chwae, U.; Ahn, Y.-W.; Choi, K.-H.

    2001-09-01

    Crustal velocities within South Korea were estimated using GPS data and interpreted in terms of neotectonics. Twenty months of data for the seven GPS stations in South Korea were analyzed to estimate velocities relative to Taejon (DAEJ), a central region of South Korea. From the time series of horizontal position of each station, we estimated site velocities with an accuracy of 0.5 mm/year or better mostly. The relative velocities within the Korean peninsula are very small (~1 mm/year), convertible to strain rates in the order of 0.01 ppm/yr. They indicate the Korean peninsula is likely to be tectonically more stationary than other countries in the East Asia, for example, Japan or Taiwan. The result of GPS analysis suggests a possibility that northwestward tectonic force due to the AM (Amurian plate)-PH (Philippine Sea plate) convergence affects the southeastern part of the Korean peninsula, of which the direction is curved due to internal faults in Korea, striking nearly perpendicular to the stress trend.

  11. Tectonic significance of Currant Creek formation, north-central Utah

    SciTech Connect

    Isby, J.S.; Picard, M.D.

    1984-07-01

    The Currant Creek Formation is composed of conglomerate, sandstone, and fine-grained clastic rocks that crop out along the northwestern margin of the Uinta basin in north-central Utah. Lateral gradations in grain size define proximal, medial, and distal parts of coalescing alluvial-fan deposits that prograded eastward from the active Sevier-Laramide orogenic belt during Maestrichtian through Paleocene (.) time. Paleocurrent directions indicate a dominant southerly transport direction and a minor easterly component. Strong east and southeasterly directions, measured in imbricated clasts and in sand lenses in conglomerate, indicate multiple source areas for the detritus. Source of the coarse-grained detritus in the Currant Creek Formation was the Charleston thrust sheet. Conglomeratic clasts are composed of Precambrian and Cambrian quartzite, chert derived from Cambrian and Mississippian carbonate beds, and Pennsylvanian sandstone. These rocks are exposed in the upper plate of the Charleston thrust near Deer Creek Reservoir, Mount Timpanogos, and Strawberry Reservoir. At Big and Little Cottonwood Canyons, the same rocks are exposed in the lower plate.

  12. Tectonic significance of the Valera Fault Zone, Northwestern Venezuela

    SciTech Connect

    Rodrigues, J.; Bueno, E.; Ostos, M. )

    1993-02-01

    A detailed structural study was performed at the southern end of the north-south to north-northwest Valera fault zone. The area is particularly interesting, since it lies close to the triple point were the Maracaibo and Lara blocks meet the South American plate. The fault zone is associated with an anticlinorium with the following structural features: (a) conic folds with hinges oriented N26-35E; (b) a main, left-lateral, north-northwest to north-south fault population; (c) a secondary set of dextral west-northwest faults; and (d) two secondary sets of left-lateral northwest and northeast faults. The structural pattern and the dynamic analysis of the faults, which indicated a N 46-50 W shortening, is compatible with the spatial arrangement of structures associated with a north-south to north-northwest sinistral strike-slip fault. A regional interpretation based on seismic sections tied to wells suggests a continuous and complex structural evolution including: (a) early Eocene northwesterly trending normal faulting, at the forebulge developed during the emplacement of the Lara nappes; (b) Early Neogene NW reverse faulting and inversion of early normal faults, at the transpressive zone that bounded the Maracaibo and Lara blocks; (c) Late Neogene development of the sinistral Valera fault zone to accomodate the tangential component of the relative movement between the two blocks.

  13. 15 CFR 746.4 - North Korea.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false North Korea. 746.4 Section 746.4... CONTROLS § 746.4 North Korea. (a) Licensing Requirements. As authorized by section 6 of the Export... Democratic People's Republic of Korea (North Korea), except food and medicines classified as EAR99...

  14. 15 CFR 746.4 - North Korea.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 2 2012-01-01 2012-01-01 false North Korea. 746.4 Section 746.4... CONTROLS § 746.4 North Korea. (a) Licensing Requirements. As authorized by section 6 of the Export... Democratic People's Republic of Korea (North Korea), except food and medicines classified as EAR99...

  15. 15 CFR 746.4 - North Korea.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false North Korea. 746.4 Section 746.4... CONTROLS § 746.4 North Korea. (a) Licensing Requirements. As authorized by section 6 of the Export... Democratic People's Republic of Korea (North Korea), except food and medicines classified as EAR99...

  16. 15 CFR 746.4 - North Korea.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false North Korea. 746.4 Section 746.4... CONTROLS § 746.4 North Korea. (a) Licensing Requirements. As authorized by section 6 of the Export... Democratic People's Republic of Korea (North Korea), except food and medicines classified as EAR99...

  17. 15 CFR 746.4 - North Korea.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 2 2014-01-01 2014-01-01 false North Korea. 746.4 Section 746.4... CONTROLS § 746.4 North Korea. (a) Licensing Requirements. As authorized by section 6 of the Export... Democratic People's Republic of Korea (North Korea), except food and medicines classified as EAR99...

  18. Optimal Planet Properties For Plate Tectonics Through Time And Space

    NASA Astrophysics Data System (ADS)

    Stamenkovic, Vlada; Seager, Sara

    2014-11-01

    Both the time and the location of planet formation shape a rocky planet’s mass, interior composition and structure, and hence also its tectonic mode. The tectonic mode of a planet can vary between two end-member solutions, plate tectonics and stagnant lid convection, and does significantly impact outgassing and biogeochemical cycles on any rocky planet. Therefore, estimating how the tectonic mode of a planet is affected by a planet’s age, mass, structure, and composition is a major step towards understanding habitability of exoplanets and geophysical false positives to biosignature gases. We connect geophysics to astronomy in order to understand how we could identify and where we could find planet candidates with optimal conditions for plate tectonics. To achieve this goal, we use thermal evolution models, account for the current wide range of uncertainties, and simulate various alien planets. Based on our best model estimates, we predict that the ideal targets for plate tectonics are oxygen-dominated (C/O<1) (solar system like) rocky planets of ~1 Earth mass with surface oceans, large metallic cores super-Mercury, rocky body densities of ~7000kgm-3), and with small mantle concentrations of iron 0%), water 0%), and radiogenic isotopes 10 times less than Earth). Super-Earths, undifferentiated planets, and especially hypothetical carbon planets, speculated to consist of SiC and C, are not optimal for the occurrence of plate tectonics. These results put Earth close to an ideal compositional and structural configuration for plate tectonics. Moreover, the results indicate that plate tectonics might have never existed on planets formed soon after the Big Bang—but instead is favored on planets formed from an evolved interstellar medium enriched in iron but depleted in silicon, oxygen, and especially in Th, K, and U relative to iron. This possibly sets a belated Galactic start for complex Earth-like surface life if plate tectonics significantly impacts the build up

  19. Petrologic implications of plate tectonics.

    PubMed

    Yoder, H S

    1971-07-30

    Petrologists can make significant contributions to the plate tectonic concept. Fixing the stability fields of the principal rock types involved will provide the limits of pressure and temperature of the various environments. Experimental determination of the partition coefficients of the trace elements will be helpful. Studies of the partial melting behavior of possible parental materials in the absence and presence of water, especially the undersaturated region, will contribute to the understanding of magma production. Experimental observations on the rheological properties of the peridotites below and just above the solidus will lead to a better evaluation of the convective mechanism. Measurement of the fundamental properties of rocks, such as the density of solids and liquids at high pressures and temperatures, would contribute to understanding the concepts of diapiric rise, magma segregation, and the low-velocity zone. Broader rock sampling of the oceanic areas of all environments will do much to define the petrologic provinces. The field petrologist specializing in the Paleozoic regions and Precambrian shields can contribute by examining those regions for old plate boundaries and devising new criteria for their recognition.

  20. Exploring Active Tectonics in the Dominican Republic

    NASA Astrophysics Data System (ADS)

    Carbó-Gorosabel, A.; Córdoba-Barba, D.; Martín-Dívila, J.; Granja-Bruña, J. L.; Llanes Estrada, P.; Muñoz-Martín, A.; ten Brink, U. S.

    2010-07-01

    The devastating 12 January 2010 Haiti earthquake (M = 7.0), which killed an estimated 230,000 people and caused extensive damage to homes and buildings, drew attention to the crucial need for improved knowledge of the active tectonics of the Caribbean region. But even before this disastrous event, interest in understanding the active and complex northeastern Caribbean plate boundary had been increasing, because this region has experienced significant seismic activity during the past century and has an extensively documented record of historical seismicity and tsunamis. Moreover, this is an easily accessible region in which to study the continuity of seismic faults offshore and to try to understand the transitions between strike-slip and convergent tectonic regimes. Interest in the region has led to several studies that have improved scientists' knowledge of subduction zone tectonics and earthquake and tsunami hazard assessments 005BMann et al., 2002; ten Brink et al., 2006, 2009; Grindlay et al., 2005; Manaker et al., 2008; Granja Bruña et al., 2009; Mondziel et al., 2010].

  1. Mimas: Tectonic structure and geologic history

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1991-01-01

    Mimas, the innermost of the major saturnian satellites, occupies an important place in comparative studies of icy satellites. It is the smallest icy satellite known to have a mostly spherical shape. Smaller icy objects like Hyperion and Puck are generally irregular in shape, while larger ones like Miranda and Enceladus are spherical. Thus Mimas is near the diameter where the combination of increasing surface gravity and internal heating begin to have a significant effect on global structure. The nature and extent of endogenic surface features provide important constraints on the interior structure and history of this transitional body. The major landforms on Mimas are impact craters. Mimas has one of the most heavily cratered surfaces in the solar system. The most prominent single feature on Mimas is Herschel, an unrelaxed complex crater 130 km in diameter. The only other recognized landforms on Mimas are tectonic grooves and lineaments. Groove locations were mapped by Schenk, but without analysis of groove structures or superposition relationships. Mimas' tectonic structures are remapped here in more detail than previously has been done, as part of a general study of tectonic features on icy satellites.

  2. Clinical neuropsychology in South Korea.

    PubMed

    Kim, Myung-Sun; Chey, Jeanyung

    2016-11-01

    Clinical neuropsychology in South Korea, albeit its relatively short history, has advanced dramatically. We review a brief history and current status of clinical neuropsychology in South Korea. The history, the educational pathway, the training pathway, the certification process, and careers in clinical neuropsychology in South Korea are reviewed. We have reviewed the neuropsychological services, including assessment and treatment, research on neurological and psychiatric populations, and neuropsychology education and the requirements related to education, training, and board examinations of those providing neuropsychological services in South Korea. We also describe how the Korean Society for Neuropsychology Research, the first and only meeting for neuropsychologists in the country established in 1999, has played a major role in how clinical neuropsychology is practiced and developed as a professional field in South Korea. Clinical neuropsychology in South Korea has achieved major progress over just a quarter of a century, and its future is promising in light of the increasing demand for neuropsychological services and advances in neuroscience in the country. Challenges that the community of clinical neuropsychologists are currently facing in South Korea, including formalizing neuropsychological curriculum and training programs and developing advanced credentialing procedures, are discussed.

  3. Molecular tectonics: from simple tectons to complex molecular networks.

    PubMed

    Hosseini, Mir Wais

    2005-04-01

    Molecular networks in the crystalline phase are infinite periodic molecular assemblies formed under self-assembly conditions between self-complementary or complementary tectons. These millimeter-size structures may be regarded as hypermolecules formed by supramolecular synthesis using reversible intertecton interactions. Molecular tectonics, based on molecular recognition events and their iteration, is the approach dealing with design and preparation of molecular networks in the solid state. In this Account, an overview of the rational behind this approach is presented. A variety of molecular networks based on van der Waals interactions and hydrogen and coordination bonding possessing diverse connectivity and topology are discussed.

  4. Tectonics of Western Canada From GPS Observations

    NASA Astrophysics Data System (ADS)

    Mazzotti, S.; Flueck, P.; Hyndman, R. D.; Dragert, H.; Craymer, M.; Schmidt, M.

    2002-12-01

    Western Canada can be divided into three main current tectonic domains: The Cascadia subduction zone, the Queen Charlotte transform margin, and the Yukon intraplate deformation region. Well-developed GPS monitoring of present-day deformation has contributed substantially to our knowledge of the dynamics of the Cascadia margin. To the north, although seismicity and plate tectonics model indicate significant deformation, our understanding of the detailed tectonics is still sparse. We present a summary of GPS measurements obtained in western Canada and adjacent regions over the last 10 years that allow us to better apprehend these three tectonic systems. Along the Cascadia margin, the Juan de Fuca (JF) plate subducts beneath North America (NA). The crustal velocity field is well constrained by continuous and campaign GPS data that show a northeastward motion that decreases landward from ~10 to ~5 mm/yr. This deformation pattern indicates significant elastic shortening of the forearc due to the locking of the subduction thrust. The northernmost Cascadia region corresponds to a transition between subduction and transform regimes. GPS campaign data suggest that this transition is accommodated by internal deformation and underthrusting of the Explorer plate beneath the NA margin. Further to the north, the Queen Charlotte Fault (QCF) accommodates the strike-slip motion between the Pacific (PA) and the NA plates. The slight obliquity of the PA/NA motion relative to the QCF direction implies some convergence along this margin. GPS campaign data in the Queen Charlotte Islands indicate velocities of 5-15 mm/yr northward with respect to NA. These results suggest a complex interaction between strain loading along the locked QCF, strain loading along a subduction thrust just offshore, and potential long-term deformation of the NA margin up to the Alaska Panhandle. The PA/NA transform margin changes to a convergence system in the Gulf of Alaska, where the Yakutat Terrane is

  5. Caribbean paleomagnetism and tectonic evolution

    SciTech Connect

    MacDonald, W.D.

    1985-01-01

    Approximately fifty papers treating diverse aspects of Caribbean paleomagnetism have appeared since Creer's pioneering work in the early 1960s. Apparently anomalous early results were initially attributed to anomalous geomagnetic field behavior, to unusual mineralogic effects in rock magnetism and to complex remagnetizations. Eventually the importance of structural and tectonic influences were recognized in paleomagnetic data of the Caribbean area, as elsewhere. Large tectonic rotation is evident from the unusual paleomagnetic declination found at many Caribbean localities. Latitudinal transport, with its plate motion implications, is more subtly expressed in the paleomagnetic inclination parameter, with its typically large relative variance. A review of Caribbean paleomagnetic data is given to form a basis for composing realistic tectonic models.

  6. Tectonics of the Easter plate

    NASA Technical Reports Server (NTRS)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  7. Occupational Asthma in Korea

    PubMed Central

    Kim, Kyoo Sang

    2010-01-01

    Occupational asthma (OA) is the leading occupational respiratory disease. Cases compensated as OA by the Korea Workers' Compensation and Welfare Service (COMWEL) (218 cases), cases reported by a surveillance system (286 cases), case reports by related scientific journals and cases confirmed by the Occupational Safety and Health Research Institute (OSHRI) over 15 yr from 1992 to 2006 were analyzed. Annual mean incidence rate was 1.6 by compensation and 3.5 by surveillance system, respectively. The trend appeared to increase according to the surveillance system. Incidence was very low compared with other countries. The most frequently reported causative agent was isocyanate followed by reactive dye in dyeing factories. Other chemicals, metals and dust were also found as causative agents. OA was underreported according to compensation and surveillance system data. In conclusion, a more effective surveillance system is needed to evaluate OA causes and distribution, and to effectively prevent newly developing OA. PMID:21258586

  8. Occupational Infection in Korea

    PubMed Central

    Ahn, Yeon-Soon; Jeong, Jae Sim

    2010-01-01

    Occupational infection is a human disease caused by work-associated exposure to microbial agents through human and environmental contact. According to the literature, occupational infection was the third leading cause of occupational disease (861 cases, 8.0%), and health care, agricultural, forestry, and fishery workers were risk groups in Korea. In addition, most high-risk groups have not been protected by workers' compensation, which could lead to underestimation of the exact spectrum and magnitude of the problem, and may also result in a lack of development and implementation of occupational infection management. Through a review of national guidelines and documentations on prevention and control of occupational infection, a management strategy would promote adherence to worker safety regulations if it is explicit with regard to the agent and mode of infection in each of the high-risk groups. PMID:21258592

  9. Water Tectonics: Evidence That Hydration Plays a Role in Tectonism

    NASA Astrophysics Data System (ADS)

    Lowry, A. R.; Schutt, D.; Perez-Gussinye, M.; Buehler, J. S.; Berry, M. A.; Ma, X.; Ravat, D.

    2015-12-01

    Several new observations provide evidence that water may play a more important role in tectonism than previously realized. Among these, • Thermodynamical modeling suggests that hydration promotes crustal mineral assemblages with lowered vP/vS and decreased density. This sheds new light on the significance of low crustal vP/vS measured in the western U.S. Cordillera from joint inversion of EarthScope USArray receiver functions and gravity. vP/vS, previously interpreted in terms of quartz abundance, is strikingly low throughout the highest-elevation regions of the western Cordillera. • Rheological modeling of flexural rigidity measurements also can be used to map water variations, primarily in the uppermost mantle. Mantle hydration estimated from flexural rigidity exhibits very similar spatial distribution to crustal hydration inferred from vP/vS, with the notable exception that the Wyoming craton has dry mantle lithosphere but a hydrous crust. • In hydrated lithosphere of the high-elevation western U.S. Cordillera, Moho temperatures estimated from Pn velocities are systematically colder than predictions by simple geothermal models of surface heat flow. These differences can only be reconciled by invoking a previously unrecognized advective term in the deep thermal transfer. • New and improved estimates of magnetic bottom are much deeper than the depth of the magnetite Curie temperature in some apparently hydrous lithosphere (notably, east of the Siletzia accreted terrane). This may indicate exotic magnetic mineralogies thought to occur only under hydrous conditions. Lithospheric hydration may be driven either by dehydration of subducted slab or by entrainment of water into upwellings passing through the mantle transition zone. Conceptualizing hydration as a large-scale process accompanied by increased buoyancy and decreased ductile strength, coupled with widespread changes in mineralogy, mass and energy transfer may help to illuminate many otherwise

  10. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.

  11. Venus magmatic and tectonic evolution

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.; Hansen, V. L.

    1993-01-01

    Two years beyond the initial mapping by the Magellan spacecraft, hypotheses for the magmatic and tectonic evolution of Venus have become refined and focused. We present our view of these processes, attempting to synthesize aspects of a model for the tectonic and magmatic behavior of the planet. The ideas presented should be taken collectively as an hypothesis subject to further testing. The quintessence of our model is that shear and buoyancy forces in the upper boundary layer of mantle convection give rise to a spatially and temporally complex pattern of strain in a one-plate Venusian lithosphere and modulate the timing and occurrence of magmatism on a global basis.

  12. Baektu Mountain, China & North Korea

    NASA Image and Video Library

    2014-07-14

    This image from NASA Terra spacecraft shows Baektu Mountain, an active volcano on the border between North Korea and China. Rising to 2744 m, its summit caldera is filled with a crater lake, Heaven Lake.

  13. EPA Collaboration with South Korea

    EPA Pesticide Factsheets

    EPA, the Ministry of Environment of Korea, and partner agencies in both countries cooperate to strengthen environmental governance, improve air and water quality, and reduce exposure to toxic chemicals.

  14. South Korea and the Future.

    ERIC Educational Resources Information Center

    Shin, Se Ho

    1988-01-01

    Examines projections about the future of Korea, predicting a highly diversified society built upon industrialization and moving toward an information society. Discusses the growing middle class and its societal implications and considers the effects of the country's increasing democratization. (GEA)

  15. Reducing Plate Tectonic Misconceptions with Lecture Tutorials

    NASA Astrophysics Data System (ADS)

    Kortz, K. M.; Smay, J. M.; Mattera, A. V.; Clark, S. K.

    2009-12-01

    In order to address student difficulties with and common misconceptions about plate tectonics, we created five Lecture Tutorials suitable for introductory geoscience courses. Lecture Tutorials are 10-15 minute worksheets that students complete in class in small groups to make learning more student-centered. Students build their knowledge with questions that progressively become more difficult, requiring them think about their misconceptions. Our research indicates that the Lecture Tutorials successfully decrease student misconceptions. For example, few introductory students identify the mantle wedge as the location of melting at subduction zones. Instead, students frequently think melting occurs at the trench, in magma chambers within volcanoes, or where images commonly show the subducting slab disappearing. One of the Lecture Tutorials helps the students determine why melting occurs and therefore identify the correct locations of melting at convergent boundaries, divergent boundaries, and hotspots. This Lecture Tutorial includes a hypothetical “debate” with statements expressing the misconceptions and one expressing the correct scientific idea of where melting occurs. Students are asked to explain why they agree with one of the statements, so they must directly think about any misconceptions they may have. Additional difficulties addressed by the Lecture Tutorials include identification of the direction of plate movement at ocean ridges and the locations and formation of basic plate tectonic features, such as trenches, volcanoes, ocean ridges, and plate boundaries. After instruction, students completed questionnaires that probed their understanding of plate tectonics, and students who completed the Lecture Tutorials performed significantly better on relevant questions. For example, when asked to circle the locations on a diagram where melting occurred, students who completed the Lecture Tutorials correctly circled the mantle wedge more often than other

  16. Pediatric liver transplantation outcomes in Korea.

    PubMed

    Kim, Jong Man; Kim, Kyung Mo; Yi, Nam-Joon; Choe, Yon Ho; Kim, Myung Soo; Suh, Kyung Suk; Kim, Soon I I; Lee, Suk-Koo; Lee, Sung-Gyu

    2013-01-01

    Pediatric liver transplantation is the standard of care for treatment of liver failure in children. The aim of this study was to identify the characteristics of pediatric liver transplantation in centers located in Korea and determine factors that influence outcomes. This retrospective study was performed using data from between 1988 and 2010 and included all recipients 18 yr old and younger who underwent pediatric liver transplantation in Korea during that period. Our data sources were hospital medical records and the outcome measure was overall patient survival. Univariate and multivariate statistical analyses were undertaken using the Cox proportional hazards model. Five hundred and thirty-four pediatric liver transplantations were performed in 502 children. Median age and average pediatric end-stage liver disease (PELD) score were 20 months and 18 point, respectively. Biliary atresia (57.7%, 308/534) was the most common cause of liver disease. Eighty-two (15.3%) were deceased donor liver transplantations and 454 (84.7%) were living donor liver transplantations. Retransplantation was performed in 32 cases (6%). Overall, 1-, 5-, and 10-yr patient survival rates were 87.8%, 82.2%, and 78.1%, respectively. In multivariate analysis, independent significant predictors of poor patient survival were chronic rejection and retransplantation. This study presents the epidemiologic data for nearly all pediatric liver transplantation in Korea and shows that the independent prognostic factors in patient survival are chronic rejection and retransplantation.

  17. North Korea: Terrorism List Removal

    DTIC Science & Technology

    2010-01-06

    Chin Se-ku. Yongbyon nuclear facility can be disabled within a year. JongAng Ilbo (internet version), March 13, 2007. 30 Abductions by N. Korea not...3007. 33 Choe Sang- hun and David E. Sanger, North Korea claims U.S. will remove sanctions, International Herald Tribune, September 4, 2007, p. 5...spring of 2007 to smuggle conventional arms, including machine guns , automatic rifles, and anti-tank rocket launchers, to the Tamil Tigers in Sri

  18. Korea's developmental program for superconductivity

    NASA Technical Reports Server (NTRS)

    Hong, Gye-Won; Won, Dong-Yeon; Kuk, Il-Hyun; Park, Jong-Chul

    1995-01-01

    Superconductivity research in Korea was firstly carried out in the late 70's by a research group in Seoul National University (SNU), who fabricated a small scale superconducting magnetic energy storage system under the financial support from Korea Electric Power Company (KEPCO). But a few researchers were involved in superconductivity research until the oxide high Tc superconductor was discovered by Bednorz and Mueller. After the discovery of YBaCuO superconductor operating above the boiling point of liquid nitrogen (77 K)(exp 2), Korean Ministry of Science and Technology (MOST) sponsored a special fund for the high Tc superconductivity research to universities and national research institutes by recognizing its importance. Scientists engaged in this project organized 'High Temperature Superconductivity Research Association (HITSRA)' for effective conducting of research. Its major functions are to coordinate research activities on high Tc superconductivity and organize the workshop for active exchange of information. During last seven years the major superconductivity research has been carried out through the coordination of HITSRA. The major parts of the Korea's superconductivity research program were related to high temperature superconductor and only a few groups were carrying out research on conventional superconductor technology, and Korea Atomic Energy Research Institute (KAERI) and Korea Electrotechnology Research Institute (KERI) have led this research. In this talk, the current status and future plans of superconductivity research in Korea will be reviewed based on the results presented in interim meeting of HITSRA, April 1-2, 1994. Taejeon, as well as the research activity of KAERI.

  19. Stress drops of induced and tectonic earthquakes in the central United States are indistinguishable

    PubMed Central

    Huang, Yihe; Ellsworth, William L.; Beroza, Gregory C.

    2017-01-01

    Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable median stress drop to tectonic earthquakes in the central United States that are dominantly strike-slip but a lower median stress drop than that of tectonic earthquakes in the eastern North America that are dominantly reverse-faulting. This suggests that ground motion prediction equations developed for tectonic earthquakes can be applied to induced earthquakes if the effects of depth and faulting style are properly considered. Our observation leads to the notion that, similar to tectonic earthquakes, induced earthquakes are driven by tectonic stresses. PMID:28782040

  20. Stress drops of induced and tectonic earthquakes in the central United States are indistinguishable.

    PubMed

    Huang, Yihe; Ellsworth, William L; Beroza, Gregory C

    2017-08-01

    Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable median stress drop to tectonic earthquakes in the central United States that are dominantly strike-slip but a lower median stress drop than that of tectonic earthquakes in the eastern North America that are dominantly reverse-faulting. This suggests that ground motion prediction equations developed for tectonic earthquakes can be applied to induced earthquakes if the effects of depth and faulting style are properly considered. Our observation leads to the notion that, similar to tectonic earthquakes, induced earthquakes are driven by tectonic stresses.

  1. Tectonics and Terranes in the Undergraduate Curriculum.

    ERIC Educational Resources Information Center

    Lambert, Richard St J.

    1989-01-01

    Gives the background to the philosophy for the introductory teaching of global tectonics and the terrane concept. Provides a discussion of local and general considerations, the curriculum, and terrane tectonics. (RT)

  2. Seismology: tectonic strain in plate interiors?

    PubMed

    Calais, E; Mattioli, G; DeMets, C; Nocquet, J-M; Stein, S; Newman, A; Rydelek, P

    2005-12-15

    It is not fully understood how or why the inner areas of tectonic plates deform, leading to large, although infrequent, earthquakes. Smalley et al. offer a potential breakthrough by suggesting that surface deformation in the central United States accumulates at rates comparable to those across plate boundaries. However, we find no statistically significant deformation in three independent analyses of the data set used by Smalley et al., and conclude therefore that only the upper bounds of magnitude and repeat time for large earthquakes can be inferred at present.

  3. Statistical description of tectonic motions

    NASA Technical Reports Server (NTRS)

    Agnew, Duncan Carr

    1993-01-01

    This report summarizes investigations regarding tectonic motions. The topics discussed include statistics of crustal deformation, Earth rotation studies, using multitaper spectrum analysis techniques applied to both space-geodetic data and conventional astrometric estimates of the Earth's polar motion, and the development, design, and installation of high-stability geodetic monuments for use with the global positioning system.

  4. Petroleum occurrences and plate tectonics

    SciTech Connect

    Olenin, V.B.; Sokolov, B.A.

    1983-01-01

    This paper analyzes the mechanisms of petroleum formation and petroleum accumulation proposed in recent years by some Russian and foreign investigators from the viewpoint of the new global or plate tectonics. On the basis of discussion and the facts, the authors conclude that the mechanisms proposed are in contradiction to reality and their use in practical application is at least premature.

  5. Comment on "Intermittent plate tectonics?".

    PubMed

    Korenaga, Jun

    2008-06-06

    Silver and Behn (Reports, 4 January 2008, p. 85) proposed that intermittent plate tectonics may resolve a long-standing paradox in Earth's thermal evolution. However, their analysis misses one important term, which subsequently brings their main conclusion into question. In addition, the Phanerozoic eustasy record indicates that the claimed effect of intermittency is probably weak.

  6. Incorporation of New and Old Tectonics Concepts Into a Modern Course in Tectonics.

    ERIC Educational Resources Information Center

    Hatcher, Robert D., Jr.

    1983-01-01

    Describes a graduate-level tectonics course which includes the historical basis for modern tectonics concepts and an in-depth review of pros/cons of plate tectonics. Tectonic features discussed include: ocean basins; volcanic arcs; continental margins; continents; orogenic belts; foreland fold and thrust belts; volcanic/plutonic belts of orogens;…

  7. Incorporation of New and Old Tectonics Concepts Into a Modern Course in Tectonics.

    ERIC Educational Resources Information Center

    Hatcher, Robert D., Jr.

    1983-01-01

    Describes a graduate-level tectonics course which includes the historical basis for modern tectonics concepts and an in-depth review of pros/cons of plate tectonics. Tectonic features discussed include: ocean basins; volcanic arcs; continental margins; continents; orogenic belts; foreland fold and thrust belts; volcanic/plutonic belts of orogens;…

  8. Plate tectonics conserves angular momentum

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2009-03-01

    A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s-1). Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates). Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth). The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive features, and fracture zones (and wedge-shaped sites

  9. Extensional tectonics of the Saturnian Satellites

    NASA Technical Reports Server (NTRS)

    Moore, J. M.

    1985-01-01

    The saturnian satellites were imaged by the Voyager spacecraft at sufficient resolutions to reveal landforms that indicate histories of extensional tectonics for several of these bodies. The relationships among landforms on various satellites imply that extensional tectonism is a consequence of several different energy sources. Case histories of several satellites are discussed to illustrate the interaction of various phenomena associated with extensional tectonism.

  10. Source contributions to carbonaceous aerosol concentrations in Korea

    NASA Astrophysics Data System (ADS)

    Jeong, Jaein I.; Park, Rokjin J.; Woo, Jung-Hun; Han, Young-Ji; Yi, Seung-Muk

    2011-02-01

    We estimated the source contributions to carbonaceous aerosol concentration in Korea on the basis of Intercontinental Chemical Transport Experiment Phase B (INTEX-B) anthropogenic emissions and satellite-derived biomass burning emissions by using a nested version of GEOS-Chem with a spatial resolution of 0.5° × 0.667° for the period March 2006-February 2007. First, we evaluated the model by comparing the simulated and observed aerosol concentrations at East Asia Network (EANET) sites and at a site in Korea. The results indicate that the model reproduces the variability and magnitudes of the observed SO 42-, NO 3-, and NH 4+ concentrations in Korea and those of the observed PM 10 concentrations in East Asia. However, the organic carbon (OC) and black carbon (BC) aerosol concentrations estimated by the model are lower than those observed in Korea by a factor of 2, especially in winter. This underestimation is likely due to extremely low domestic anthropogenic emissions and lack in seasonal variation. Source adjustments using a simple fitting and the Emission Database for Global Atmospheric Research (EDGAR) monthly allocation factors for seasonal variation yield significantly improved model results ( R2 increased from 0.58 to 0.84), which can then be used to estimate the source contributions to the OC and BC concentrations in Korea. We found that domestic anthropogenic emissions are the most important factors, contributing 74% (9% from fossil fuels and 65% from biofuels) and 78% (42% from fossil fuels and 36% from biofuels) to the OC and BC concentrations, respectively, on an annual mean basis in Korea. The trans-boundary transport of Chinese sources is another important factor, contributing 13% and 20% to the OC and BC concentrations, respectively. The contributions of wildfires and biogenic sources to the annual mean carbonaceous aerosol concentration in Korea are relatively small (4% and 6%, respectively).

  11. Korea Research Reactor -1 & 2 Decommissioning Project in Korea

    SciTech Connect

    Park, S. K.; Chung, U. S.; Jung, K. J.; Park, J. H.

    2003-02-24

    Korea Research Reactor 1 (KRR-1), the first research reactor in Korea, has been operated since 1962, and the second one, Korea Research Reactor 2 (KRR-2) since 1972. The operation of both of them was phased out in 1995 due to their lifetime and operation of the new and more powerful research reactor, HANARO (High-flux Advanced Neutron Application Reactor; 30MW). Both are TRIGA Pool type reactors in which the cores are small self-contained units sitting in tanks filled with cooling water. The KRR-1 is a TRIGA Mark II, which could operate at a level of up to 250 kW. The second one, the KRR-2 is a TRIGA Mark III, which could operate at a level of up 2,000 kW. The decontamination and decommissioning (D & D) project of these two research reactors, the first D & D project in Korea, was started in January 1997 and will be completed to stage 3 by 2008. The aim of this decommissioning program is to decommission the KRR-1 & 2 reactors and to decontaminate the residual building structure s and the site to release them as unrestricted areas. KAERI (Korea Atomic Energy Research Institute) submitted the decommissioning plan and the environmental impact assessment reports to the Ministry of Science and Technology (MOST) for the license in December 1998, and was approved in November 2000.

  12. Archipelago Tidal Flats in Korea: Sedimentological and Geoheritage Significance

    NASA Astrophysics Data System (ADS)

    Woo, Kyung Sik; Chun, SeungSoo; Moon, Kyong O.

    2015-04-01

    Over one thousand islands with rocky shores are distributed and concentrated along the southwestern coast of the Korean Peninsula. Various tidal flats formed along the rocky coasts of the archipelago have been developed due to the relative decrease in accommodation space by slow sea-level rise on broad marginal epicontinental seas during the Holocene. Sedimentation and evolution on these archipelago tidal flats (ATF) show quite distinctive and various tidal flat patterns, depending upon the location and direction of rocky shores which have been constantly influenced by monsoon winds reversely changing with season. Generally ATF is characterized by surrounding wave-dominated sand flats along the outside of the archipelago and by broad tide-dominated mud flats in its central part with spring tidal range reaching up to 6 meters. The open-coast outside sand flats and inner mud flats are completely different in terms of sedimentation and the evolution of sedimentary sequences. The former has been deposited by the transgressive sedimentation with strongly destructive and weakly constructive wave/tide processes, forming relative thin and younger (ca. 3,000 yrs BP) remnant storm-dominated sandflat units. The latter has been deposited by continuous transgressive settling with constructive tidal processes during Holocene, forming relative thick and older (from ca. 7,000 yrs BP) mud-flat units. Geomorphological features and the geological evolution of the ATF (Shinan archipelago and Yoobudo islands in Seocheon) display a quite distinctive pattern of ongoing geological processes from the Wadden Sea tidal flats which was already inscribed as World Natural Heritage. Therefore, the Outstanding Universal Values of the Korean ITF for criteria (vii) and (viii) should provide a strong support for the additional World Natural Heritage Site.

  13. Successful Control of Lymphatic Filariasis in the Republic of Korea

    PubMed Central

    Cheun, Hyeng-Il; Kong, Yoon; Cho, Shin-Hyeong; Lee, Jong-Soo; Chai, Jong-Yil; Lee, Joo-Shil; Lee, Jong-Koo

    2009-01-01

    A successful experience of lymphatic filariasis control in the Republic of Korea is briefly reviewed. Filariasis in the Republic of Korea was exclusively caused by infection with Brugia malayi. Over the past several decades from the 1950s to 2006, many investigators exerted their efforts to detection, treatment, and follow-up of filariasis patients in endemic areas, and to control filariasis. Mass, combined with selective, treatments with diethylcarbamazine to microfilaria positive persons had been made them free from microfilaremia and contributed to significant decrease of the microfilarial density in previously endemic areas. Significant decrease of microfilaria positive cases in an area influenced eventually to the endemicity of filariasis in the relevant locality. Together with remarkable economic growth followed by improvement of environmental and personal hygiene and living standards, the factors stated above have contributed to blocking the transmission cycle of B. malayi and led to disappearance of this mosquito-borne ancient disease in the Republic of Korea. PMID:19967079

  14. Successful control of lymphatic filariasis in the Republic of Korea.

    PubMed

    Cheun, Hyeng-Il; Kong, Yoon; Cho, Shin-Hyeong; Lee, Jong-Soo; Chai, Jong-Yil; Lee, Joo-Shil; Lee, Jong-Koo; Kim, Tong-Soo

    2009-12-01

    A successful experience of lymphatic filariasis control in the Republic of Korea is briefly reviewed. Filariasis in the Republic of Korea was exclusively caused by infection with Brugia malayi. Over the past several decades from the 1950s to 2006, many investigators exerted their efforts to detection, treatment, and follow-up of filariasis patients in endemic areas, and to control filariasis. Mass, combined with selective, treatments with diethylcarbamazine to microfilaria positive persons had been made them free from microfilaremia and contributed to significant decrease of the microfilarial density in previously endemic areas. Significant decrease of microfilaria positive cases in an area influenced eventually to the endemicity of filariasis in the relevant locality. Together with remarkable economic growth followed by improvement of environmental and personal hygiene and living standards, the factors stated above have contributed to blocking the transmission cycle of B. malayi and led to disappearance of this mosquito-borne ancient disease in the Republic of Korea.

  15. The Diabetes Epidemic in Korea

    PubMed Central

    2016-01-01

    Diabetes is one of the foremost public health issues worldwide that can lead to complications in many organ systems, and has become a significant cause of morbidity and mortality in Korea. According to data from the National Health Insurance Service (NHIS), about 2.7 million Koreans (8.0%) aged 30 years or older had type 2 diabetes mellitus (T2DM) in 2013. The prevalence of T2DM increased with age and rose from 5.6% in 2006 to 8.0% in 2013. Using data based on The Health Screening Service of the NHIS, 25% of Korean adults were reported to have prediabetes in 2013. The prevalence of an impaired fasting glucose tended to increase over time from 21.5% in 2006 to 25.0% in 2013. Even though nationwide health screening has been regularly conducted as a public service, the proportion of undiagnosed cases of diabetes was still reported to be on the higher side in the latest study. Based on the results of these epidemic studies, further actions will be needed to effectively implement lifestyle changes on a social level and increase measures for the early detection of diabetes to stem the tide of the epidemic. PMID:27586447

  16. Occupational Diseases in Korea

    PubMed Central

    Kim, Eun A

    2010-01-01

    Korea has industrialized since the 1970s. Pneumoconiosis in coal miners was the most common occupational disease in the 1970s to 1980s. With the industrialization, the use of many chemicals have increased since the 1970s. As a consequence, there were outbreaks of occupational diseases caused by poisonous chemicals, such as heavy metal poisoning, solvent poisoning and occupational asthma in the late 1980s and early 1990s with civil movement for democracy. Many actions have been taken for prevention by the government, employers and employees or unions. In the 1990s most chemical related diseases and pneumoconiosis have rapidly decreased due to improving work environment. In the late 1990s, cerebro-cardiovascular diseases related to job stress or work overloads have abruptly increased especially after the economic crisis in 1998. After the year 2000, musculoskeletal disorders became a major problem especially in assembly lines in the manufacturing industry and they were expanded to the service industry. Mental diseases related to job stress have increased. Infectious diseases increased in health care workers and afforestation workers. Occupational cancers are increasing because of their long latency, although the use of carcinogenic substances are reduced, limited, and even banned. PMID:21258589

  17. Dust Obscures Korea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The dust cloud over eastern Asia was so thick on March 21, 2002, that the Korean Peninsula completely disappeared from view in this Sea-viewing Wide Field-of-view Sensor (SeaWiFS) image of the region. Parts of South Korea report that visibility at the surface is less than 50 m (165 feet). Airports throughout the region canceled flights due to the poor visibility. Eyewitnesses in China report that the dust was so thick in Beijing at times that visibility was limited to 100 m (330 feet), while in parts of the Gansu Province visibility was reported at less than 10 m (33 feet). Chinese officials say this is the worst dust storm to hit in more than 10 years. Dust from an earlier event still colors the air to the east of Japan. (The island of Honshu is just peeking out from under the cloud cover in these images.) Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  18. 78 FR 66785 - Korea Hydro and Nuclear Power Co., Ltd., and Korea Electric Power Corporation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-06

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Korea Hydro and Nuclear Power Co., Ltd., and Korea Electric Power Corporation AGENCY: Nuclear... APR1400 Standard Plant Design submitted by Korea Hydro and Nuclear Power Co., Ltd. (KHNP) and Korea...

  19. Tectonic factors controlling initiation and distribution of Silurian reefs in Illinois basin, southwestern Indiana

    SciTech Connect

    Furer, L.C. )

    1989-08-01

    The authors discuss the relative effects of differential compaction and tectonics on the distribution, growth, geometry, and age of Silurian reefs in the Illinois basis. Their working hypothesis is that both differential compaction and tectonics have had a significant effect on the reefs, each at a different time. Examples are given.

  20. Planets and satellites: tectonic twins

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2015-10-01

    There are only three solid planet-satellite pairs in the Solar system: Earth -Moon, Mars -Phobos, Pluto - Charon. For the first two pairs tectonic analogies were shown and explained by moving them in one circumsolar orbit. As it is known from the wave planetology [3, 4, 6], "orbits make structures". For the third pair the same was stated as a prediction based on this fundamental rule. Global tectonic forms of wave origin appear in cosmic bodies because they move in keplerian orbits with periodically changing accelerations. Warping bodies waves have a stationary character and obeying wave harmonics lengths. Starting from the fundamental 2πR-long wave 1 making the ubiquitous tectonic dichotomy (two-face appearance) warping wave lengths descend along harmonics. Very prominent along with the wave 1 are waves 2 responsible for tectonic sectoring superimposed on the wave 1 segments. Practically all bodies have traces of shorter waves making numerous polygons (rings) often confused with impact craters. Earth and the Moon moving in one circumsolar orbit both are distorted by wave 1, wave 2 and wave 4 features aligned along extent tectonic lines [4, 5]. At Earth they are: Pacific Ocean (2πR-structure) and Indian Ocean (πR-structure) from both ends with Malay Archipelago (πR/4-structure) in the middle. At Moon they are: Procellarum Ocean (2πR) and SPA Basin (πR) from ends and Mare Orientale (πR/4) in the middle. A regular disposition is surprising. Both Oceans and Basin occur on opposite hemispheres, lying in the middle both ring structures occur in the boundary between two hemispheres and are of the same relative size. These triads stretch along lines parallel to the equator (Earth) and with the angle about 30 degrees to it (Moon) indicating at a different orientation of the rotation axes in the ancient time [2]. On the whole, one could speak about a "lunar mould" of Earth [5] (Fig. 1-3). Another tectonic twin is the pair Mars -Phobos. Both bodies sharing one

  1. Mobilization of evaporites in tectonically active terrains

    NASA Astrophysics Data System (ADS)

    Stiros, Stathis C.

    2015-04-01

    The role of evaporites, mostly halite, during seismic sequences is investigated using evidence from certain earthquakes with magnitude between approximately 6.0 and 7.2 which occurred in the last 60 years in the Zagros Mts. (Iran) and the Ionian Sea (Greece); i.e. two seismically active areas, characterized by evaporite-associated decollements and more shallow decollements combined with mature, along-thrusts intrusions. Studied earthquakes produced either large scale surface deformation, or were covered by high-resolution and accuracy GPS and INSAR data, permitting to fully recognize the deformation pattern. In all cases an "atypical", tectonic deformation pattern was observed, ranging from apparently "impossible" patterns (thrust and normal faults, sub-parallel and homothetic; 1953 Cephalonia earthquake, Greece) to rather diffuse tectonic patterns, even to "phantom" earthquakes (Zagros). Careful analysis and modeling of the surface deformation data, in combination with the available geological, geophysical and seismological data permits to recognize, and even to quantify differences between deformation observed, and that expected in ordinary environments. In particular, it was found that during earthquakes evaporites were mobilized, and this led either to a secondary deformation of the overburden, fully detached from the basement, or to significant aseismic (post-seismic) deformation. Anomalies in the distribution of seismic intensities due to evaporitic intrusions along faults were also observed. Apart from seismological implications (unpredictable post-seismic deformation, possibly also in the far-field), these results deriving from regions at different levels of evaporitic evolution, may prove useful to understand patterns of mobilization of evaporites during periods of tectonic activity.

  2. Distribution of lichen flora on South Korea.

    PubMed

    Hur, Jae-Seoun; Harada, Hiroshi; Oh, Soon-Ok; Lim, Kwang-Mi; Kang, Eui-Sung; Lee, Seung Mi; Kahng, Hyung-Yeel; Kim, Hyun-Woo; Jung, Jae-Sung; Koh, Young Jin

    2004-06-01

    After an overview on the temporary situation of the lichenology in South Korea, localities of 95 macrolichen taxa are reported for South Korea. In this revised lichen flora of South Korea, 16 species are apparently new to the territory. Voucher specimens have been deposited in the Korean Lichen Research Institute (KoLRI) at Sunchon National University in Korea, and duplicates have also been donated to the National History Museum and Institute, in Chiba, (CBM) Japan.

  3. Sedimentation and tectonics in the southern Bida Basin, Nigeria: depositional response to varying tectonic context

    SciTech Connect

    Braide, S.P. )

    1990-05-01

    The Upper Cretaceous Bida basin of central Nigeria is sandwiched between the Precambrian schist belts of the Northern Nigerian massif and the West African craton. Of interest is the southern part of the basin, which developed in continental settings, because the facies architecture of the sedimentary fill suggests a close relation between sedimentation dynamics and basin margin tectonics. This relationship is significant to an understanding of the basin's origin, which has been controversial. A simple sag and rift origin has been suggested, and consequently dominated the negative thinking on the hydrocarbon prospects of the basin which were considered poor. This detailed study of the facies indicates rapid basin-wide changes from various alluvial fan facies through flood-basin and deltaic facies to lacustrine facies. Paleogeographic reconstruction suggests lacustrine environments were widespread and elongate. Lacustrine environments occurred at the basin's axis and close to the margins. This suggests the depocenter must have migrated during the basin's depositional history and subsided rapidly to accommodate the 3.5-km-thick sedimentary fill. Although distinguishing pull-apart basins from rift basins, based solely on sedimentologic grounds, may be difficult, the temporal migration of the depocenter, as well as the basin architecture of upward coarsening cyclicity, show a strong tectonic and structural overprint that suggests a tectonic framework for the Southern Bida basin similar in origin to a pull-apart basin.

  4. Special Education in South Korea: Daegu University

    ERIC Educational Resources Information Center

    Kim, Byung Ha; Rhee, Kun Yong; Burns, Carol; Lerner, Janet W.

    2009-01-01

    Daegu University has enjoyed a long and remarkable history of special education. Daegu University is large University located in Daegu, South Korea, a large city in South Korea that is south of Seoul. Since the 1970's, South Korea has achieved unusual and comprehensive growth in its economy, and the field of special education continued to thrive…

  5. Special Education in South Korea: Daegu University

    ERIC Educational Resources Information Center

    Kim, Byung Ha; Rhee, Kun Yong; Burns, Carol; Lerner, Janet W.

    2009-01-01

    Daegu University has enjoyed a long and remarkable history of special education. Daegu University is large University located in Daegu, South Korea, a large city in South Korea that is south of Seoul. Since the 1970's, South Korea has achieved unusual and comprehensive growth in its economy, and the field of special education continued to thrive…

  6. 75 FR 67912 - North Korea Sanctions Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-04

    ... 31 CFR Part 510 North Korea Sanctions Regulations AGENCY: Office of Foreign Assets Control, Treasury...'') is issuing regulations with respect to North Korea to implement Executive Order 13466 of June 26... issuing the North Korea Sanctions Regulations, 31 CFR part 510 (the ``Regulations''), to implement E.O...

  7. 76 FR 35740 - North Korea Sanctions Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... Part 510 North Korea Sanctions Regulations AGENCY: Office of Foreign Assets Control, Treasury. ACTION... amending the North Korea Sanctions Regulations to implement Executive Order 13570 of April 18, 2011. OFAC..., the Department of the Treasury's Office of Foreign Assets Control published the North Korea Sanctions...

  8. Global tectonics and space geodesy

    NASA Technical Reports Server (NTRS)

    Gordon, Richard G.; Stein, Seth

    1992-01-01

    Much of the success of plate tectonics can be attributed to the near rigidity of tectonic plates and the availability of data that describe the rates and directions of motion across narrow plate boundaries of about 1 to 60 kilometers. Nonetheless, many plate boundaries in both continental and oceanic lithosphere are not narrow but are hundreds to thousands of kilometers wide. Wide plate boundary zones cover approximately 15 percent of earth's surface area. Space geodesy, which includes very long baseline radio interferometry, satellite laser ranging, and the global positioning system, provides the accurate long-distance measurements needed to estimate the present motion across and within wide plate boundary zones. Space geodetic data show that plate velocities averaged over years are remarkably similar to velocities avaraged over millions of years.

  9. Global tectonics and space geodesy.

    PubMed

    Gordon, R G; Stein, S

    1992-04-17

    Much of the success of plate tectonics can be attributed to the near rigidity of tectonic plates and the availability of data that describe the rates and directions of motion across narrow plate boundaries \\m=~\\1 to 60 kilometers wide. Nonetheless, many plate boundaries in both continental and oceanic lithosphere are not narrow but are hundreds to thousands of kilometers wide. Wide plate boundary zones cover \\m=~\\15 percent of Earth's surface area. Space geodesy, which includes very long baseline radio interferometry, satellite laser ranging, and the global positioning system, is providing the accurate long-distance measurements needed to estimate the present motion across and within wide plate boundary zones. Space geodetic data show that plate velocities averaged over years are remarkably similar to velocities averaged over millions of years.

  10. Tectonics and composition of Venus

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1980-01-01

    The uncompressed density of Venus is a few percent less than the Earth. The high upper mantle temperature of Venus deepens the eclogite stability field and inserts a partial melt field. A thick basaltic crust is therefore likely. The anomalous density of Venus relative to the progression from Mercury to Mars may therefore have a tectonic rather than a cosmo-chemical explanation. There may be no need to invoke differences in composition or oxidization state.

  11. Episodic plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Turcotte, Donald

    1992-01-01

    Studies of impact craters on Venus from the Magellan images have placed important constraints on surface volcanism. Some 840 impact craters have been identified with diameters ranging from 2 to 280 km. Correlations of this impact flux with craters on the Moon, Earth, and Mars indicate a mean surface age of 0.5 +/- 0.3 Ga. Another important observation is that 52 percent of the craters are slightly fractured and only 4.5 percent are embayed by lava flows. These observations led researchers to hypothesize that a pervasive resurfacing event occurred about 500 m.y. ago and that relatively little surface volcanism has occurred since. Other researchers have pointed out that a global resurfacing event that ceased about 500 MYBP is consistent with the results given by a recent study. These authors carried out a series of numerical calculations of mantle convection in Venus yielding thermal evolution results. Their model considered crustal recycling and gave rapid planetary cooling. They, in fact, suggested that prior to 500 MYBP plate tectonics was active in Venus and since 500 MYBP the lithosphere has stabilized and only hot-spot volcanism has reached the surface. We propose an alternative hypothesis for the inferred cessation of surface volcanism on Venus. We hypothesize that plate tectonics on Venus is episodic. Periods of rapid plate tectonics result in high rates of subduction that cool the interior resulting in more sluggish mantle convection.

  12. Earth's Decelerating Tectonic Plates (Invited)

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Moucha, R.; Rowley, D. B.; Quere, S.; Mitrovica, J. X.; Simmons, N. A.; Grand, S. P.

    2009-12-01

    We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data (Simmons et al., GJI 2009) to explore the impact of time-dependent changes in mantle buoyancy forces on tectonic plate accelerations. This plate-coupled mantle convection model incorporates a viscosity structure that reconciles both glacial isostatic adjustment and global convection-related data sets (Mitrovica & Forte, EPSL 2004) and it successfully reproduces present-day plate velocities, global surface gravity and topography data. This convection model predicts the recent deceleration of several major plates in the Pacific and Indo-Atlantic hemispheres. Independent verification of these predictions is a fundamental test of the plausibility of the buoyancy forces and rheological structure in the convection model. To this end, we consider marine magnetic anomaly and space geodetic constraints on tectonic plate motions to determine a new global map of present-day rates of change of plate velocities. This map shows that several major plates, such as the Pacific, Africa and Nazca plates are presently decelerating and that they contribute to a globally-averaged slowdown in tectonic plate speeds. These joint geologic-geodetic inferences of plate decelerations are consistent with those predicted by our tomography-based convection model.

  13. Epidemiology of Biliary Atresia in Korea

    PubMed Central

    2017-01-01

    Biliary atresia (BA) is the major cause of cholestasis and the leading indication for liver transplantation (LT). However, the incidence of BA in Korea has not been reported. The aim of this study was to investigate the incidence and clinical outcomes of BA in Korea. We used the Korean universal health insurance database and extracted data regarding BA patients younger than 18 years of age admitted between 2011 and 2015. The incidence of BA was calculated by dividing the number of BA patients by the number of live births. Two hundred forty infants were newly diagnosed with BA. A total of 963 BA patients younger than 18 years of age were followed up for 5 years. The overall incidence of BA was 1.06 cases per 10,000 live births. The incidence of BA was 1.4 times higher for female patients than for male patients. Additionally, significant seasonal variation was observed; in particular, the incidence of BA was 2 times higher from June through August than from December through February. Congenital anomalies were found in 38 of 240 patients (15.8%). Congenital heart diseases were major associated congenital anomalies (6.3%). Several complications developed during the study period, including cholangitis (24.0%), varix (6.2%), and gastrointestinal bleeding (4.4%). Three hundred and one of the 963 BA patients under 18 years of age (31.3%) received LT for BA. The incidence of BA is higher in Korea than that in Western countries. We also report significant gender-associated differences and seasonal variation with respect to the incidence of BA. PMID:28244293

  14. Health impact assessment in Korea

    SciTech Connect

    Kang, Eunjeong; Lee, Youngsoo; Harris, Patrick; Koh, Kwangwook; Kim, Keonyeop

    2011-07-15

    Recently, Health Impact Assessment has gained great attention in Korea. First, the Ministry of Environment introduced HIA within existing Environment Impact Assessment. Second, the Korea Institute for Health and Social Affairs began an HIA program in 2008 in alliance with Healthy Cities. In this short report, these two different efforts are introduced and their opportunities and challenges discussed. We believe these two approaches complement each other and both need to be strengthened. We also believe that both can contribute to the development of health in policy and project development and ultimately to improvements in the Korean population's health.

  15. Tectonic structure of East Antarctica

    NASA Astrophysics Data System (ADS)

    Leychenkov, German; Grikurov, Garrik; Golynsky, Alexander

    2013-04-01

    First overviews of tectonic structure of the Southern Continent were made by the pioneers of Antarctic earth science investigations almost 100 years ago. Despite rapidly advancing international geological studies under the Antarctic Treaty, the presentations of Antarctic tectonic structure remained largely speculative until the end of the past century when implementation of modern analytical and remote-sensing research technologies enabled compilation of more credible tectonic models of Antarctica. The East Antarctic bedrock consists mainly of the Precambrian crystalline complexes and the Paleozoic-Early Mesozoic platform units. Crystalline Shield is locally complicated by Neoproterozoic aulacogenes and Late Paleozoic to Mesozoic rifts. Shield assemblages reliably recognized in coastal outcrops indicate the predominant occurrence of Archean cratonic nuclei and Mesoproterozoic mobile belts. The undisturbed platform cover strata are exposed in East Antarctica mainly along its boundary with West Antarctica. Tectonic structure of ice-covered regions (more that 99% of the East Antarctic territory) is interpreted using mostly magnetic and bedrock topography data, but other geophysical and geological information (satellite, airborne and over-ice gravity; seismology; active seismics; erratics; detrital zircons dates; etc.) is also important. Archean cratons are geologically documented in western Dronning Maud Land, Enderby Land, Princess Elizabeth Land and in the southern Prince Charles Mts. Their distribution under the ice is marked by a specific magnetic pattern including low-amplitude mosaic and/or high-amplitude long-wavelength anomalies. The most extensive ancient craton being 1000 km across is believed to extend from the southern Prince Charles Mts. to the Gamburtsev Mts. Mesoproterozoic mobile belts are distinguished by elongated high-amplitude magnetic anomalies and are mapped along the costal area as the zone of 250-600 km wide. The Gamburtsev Mts. area is also

  16. Plate tectonics conserves angular momentum

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2010-03-01

    A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4+27 kg m2 s-1). Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates). Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies revealed by geoid anomalies of the degree 4-10 packet of the Earth's spherical harmonic coefficients. These linear positive geoid anomalies underlie plate subduction zones and are presumed due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth). The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant

  17. An Early, Transient, Impact-driven Tectonic Regime in the Hadean?

    NASA Astrophysics Data System (ADS)

    O'Neill, C.; Marchi, S.; Zhang, S.

    2015-12-01

    The earliest preserved crust formed in a tectonic regime that different from present in several significant ways. Earth was still losing a significant fraction of its primordial heat, and heat production was declining more rapidly than in any period subsequently. Additionally, a waning impact flux provided an important thermal - and mechanical - forcing on the early Earth. These factors affect tectonics in a number of ways - internal velocities are faster, and internal viscosities lower due to hotter internal temperatures. Previous modelling of the tectonic evolution of the Earth under these conditions suggests that the early Earth may have exhibited periods of hot stagnant-lid convection - where vigorous internal convection - and volcanic activity - occurred under a tectonically quiescent lid. As the Earth cooled the planet would have transited into an episodic regime - characterised by periods of tectonic quiescence interspersed by extreme tectonic activity. Such scenarios explain a number of facets of the early Earth, including its observed slow mixing rates, inefficient cooling, and its paleomagnetic and tectonic history. Here we expand these models to incorporate the effects of major impacts. We find tectonic forcing due to impacts to be a major dynamic driver during the Hadean, with major return flow driving horizontal surface deformation, and transient subduction events. Such events may be reflected in the Hadean zircon record. Post this impact-dominated phase, models suggest an over-heated Earth may have then experienced a long phase of stagnant-lid convection, lasting till the meso-Archaean.

  18. Tectonic assembly of Gondwana

    NASA Astrophysics Data System (ADS)

    Rogers, John J. W.; Unrug, Raphael; Sultan, Mohamed

    1995-01-01

    The Paleozoic assembly of Pangea, with Gondwana as its southern half, completed the last full cycle of growth and dispersal of supercontinents during earth history. This assembly apparently resulted from reorganization of a preceding supercontinent (Rodinia) that existed at ˜1000 Ma. In addition to Laurentia and fragments that formed nuclei for Europe and Asia, the rifting of Rodinia produced: (1) East Gondwana, consisting largely of Western Australia, India, East Antarctica, and possibly part of southern Africa; and (2) various smaller fragments that converged to form West Gondwana, consisting of most of Africa and South America. East Gondwana appears to have been a stable block at a time no younger than ˜1000 Ma and possibly older. West Gondwana accreted largely in the latest Proterozoic and early Paleozoic by closure of the Pharusian Ocean in the north, the Adamaster Ocean in the south, and the ANEKT/Mozambique Ocean between West and East Gondwana. The assembly process was diachronous along numerous mobile belts, accompanied by syn- and post-collisional shearing and magmatism, and led to development of successor basins and rifts. Uncertainties in the timing and mechanism of assembly of Gondwana greatly limit our understanding of the supercontinent cycle. Thus, we propose investigations of Gondwana to determine more precisely the nature and age of apparent cratonic blocks, the locations and ages of orogenic belts, the configuration of former ocean basins, the significance of transcontinental shears, the extent of reactivation of older terranes, and the relationship of Gondwana to North America. Detailed knowledge of the assembly of Gondwana should also provide information on its relationship to other major processes such as mantle evolution and atmospheric, oceanic, and biologic changes.

  19. Recent advances in the cretaceous stratigraphy of Korea

    NASA Astrophysics Data System (ADS)

    Chang, Ki-Hong; Suzuki, Kazuhiro; Park, Sun-Ok; Ishida, Keisuke; Uno, Koji

    2003-06-01

    A subrounded, accidental, zircon grain from a rhyolite sample of the Oknyobong Formation has shown an U-Pb CHIME isochron age, 187 Ma, implying its derivation from a Jurassic felsic igneous rock. Such a lower limit of the geologic age of the Oknyobong Formation, combined with its pre-Kyongsang upper limit, constrains that the Oknyobong Formation belongs to the Jasong Synthem (Late Jurassic-early Early Cretaceous) typified in North Korea. The Jaeryonggang Movement terminated the deposition of the Jasong Synthem and caused a shift of the depocenter from North Korea to the Kyongsang Basin, Southeast Korea. The Cretaceous-Paleocene Kyongsang Supergroup of the Kyongsang Basin is the stratotype of the Kyongsang Synthem, an unconformity-bounded unit in the Korean Peninsula. The unconformity at the base of the Yuchon Volcanic Group is a local expression of the interregionally recognizable mid-Albian tectonism; it subdivides the Kyongsang Synthem into the Lower Kyongsang Subsynthem (Barremian-Early Albian) and the Upper Kyongsang Subsynthem (Late Albian-Paleocene). The latter is unconformably overlain by Eocene and younger strata. The Late Permian to Early Jurassic radiolarian fossils from the chert pebbles of the Kumidong and the Kisadong conglomerates of the Aptian-Early Albian Hayang Group of the Kyongsang Basin are equivalent with those of the cherts that constitute the Jurassic accretionary prisms in Japan, the provenance of the chert pebbles in the Kyongsang Basin. Bimodal volcanisms throughout the history of the Kyongsang Basin is exemplified by the felsic Kusandong Tuff erupted abruptly and briefly in the Late Aptian when semi-coeval volcanisms were of intermediate and mafic compositions. The mean paleomagnetic direction shown by the Kusandong Tuff is in good agreement with the Early Cretaceous directions known from North China, South China and Siberia Blocks.

  20. Complaining Behavior of Academic Library Users in South Korea

    ERIC Educational Resources Information Center

    Oh, Dong-Geun

    2004-01-01

    This study investigates the influences of the antecedent factors on the complaints and resulting behaviors of 582 university library users in South Korea. There were statistically significant relationships between personal norms and negative word of mouth and indirect voice behaviors, between service importance and negative word-of-mouth behavior,…

  1. Complaining Behavior of Academic Library Users in South Korea

    ERIC Educational Resources Information Center

    Oh, Dong-Geun

    2004-01-01

    This study investigates the influences of the antecedent factors on the complaints and resulting behaviors of 582 university library users in South Korea. There were statistically significant relationships between personal norms and negative word of mouth and indirect voice behaviors, between service importance and negative word-of-mouth behavior,…

  2. Shock: South Korea wins Battle of nuclear titans

    SciTech Connect

    2010-03-15

    A South Korean consortium won the contract to build and operate four nuclear power plants in Abu Dhabi valued at $20.4 billion. The deal was significant since it is the first major nuclear contract of its kind awarded in the rapidly growing Persian Gulf region, and signals the rise of Korea as an exporter of nuclear know-how.

  3. Rural Development in South Korea.

    ERIC Educational Resources Information Center

    Brandt, Vincent S. R.

    1979-01-01

    Reviews development in rural areas of South Korea since the late nineteenth century, with particular emphasis on rural to urban migration, governmental investment in agriculture, transportation and mass communications, development projects, social leveling processes, upgraded living standards, and cooperative village improvement projects. Journal…

  4. Inclusive Education in South Korea

    ERIC Educational Resources Information Center

    Kim, Yong-Wook

    2014-01-01

    The purpose of this paper is to examine the current implementation of inclusive education in South Korea and discuss its challenges. The history of special education is first described followed by an introduction to policies relevant to special and inclusive education. Next, a critical discussion of the state of inclusive education follows built…

  5. Inclusive Education in South Korea

    ERIC Educational Resources Information Center

    Kim, Yong-Wook

    2014-01-01

    The purpose of this paper is to examine the current implementation of inclusive education in South Korea and discuss its challenges. The history of special education is first described followed by an introduction to policies relevant to special and inclusive education. Next, a critical discussion of the state of inclusive education follows built…

  6. North Korea: Terrorism List Removal

    DTIC Science & Technology

    2007-04-06

    15 Niksch, Larry A., North Korea and Terrorism: The Yokita Megumi Factor. The Korean Journal of Defense Analysis. Spring 2002. pp. 14-16. 16 For...remains were not those of Megumi Yokota or Kaoru Matsuki, as Pyongyang had claimed, and the issue remained contentious at year’s end. Four Japanese

  7. Life in South Korea Today.

    ERIC Educational Resources Information Center

    Lew, Seok-Choon

    1988-01-01

    Characterizes the past 40 years in South Korea as a time of modernization, industrialization, urbanization, and internationalization. Discusses Korean religion and social values; family, kinship, and social life; education; housing, food, and clothing; leisure and sports; and the maintenance of national identity. Examines the Korean synthesis of…

  8. Foreign Assistance to North Korea

    DTIC Science & Technology

    2005-05-26

    Representative for the DPRK. 41 Smith, Overcoming Humanitarian Dilemmas, p.13 Source: World Food Program, Map Resources. Adapted by CRS. (K. Yancey 3/18/04...2003 e-mail correspondence with Rick Corsino, former WFP Country Director for North Korea. 44 May 2005 e-mail correspondence with Richard Ragan, WFP

  9. Tectonic wedges: geometry and kinematic interpretation

    NASA Astrophysics Data System (ADS)

    Martinez-Torres, L. M.; Ramon-Lluch, R.; Eguiluz, L.

    1994-10-01

    The geometry of several tectonic wedge combinations was studied in an outcrop in the Basque Basin, Western Pyrenees. Three types of tectonic wedges were distinguished: simple, double and triple wedge. On the surface the geometry of the observed tectonic wedges is always highly elemental: emergent thrust, horse or klippe. The final stage in the evolution of a tectonic wedge is its delamination. This can occur by the spreading of the thrusts which conform the wedge, or by the development of back thrusts associated to them. The relative age of the back thrust with respect to the thrust indicates whether the original structure was a simple thrust or a tectonic wedge. If this criterion is applied to the Pyrenean Orogen, this range corresponds to a tectonic wedge.

  10. Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada

    USGS Publications Warehouse

    Whitney, John W.; O'Leary, Dennis W.

    1993-01-01

    Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada, is needed to assess seismic and possible volcanic hazards that could affect the site during the preclosure (next 100 years) and the behavior of the hydrologic system during the postclosure (the following 10,000 years) periods. Tectonic characterization is based on assembling mapped geological structures in their chronological order of development and activity, and interpreting their dynamic interrelationships. Addition of mechanistic models and kinematic explanations for the identified tectonic processes provides one or more tectonic models having predictive power. Proper evaluation and application of tectonic models can aid in seismic design and help anticipate probable occurrence of future geologic events of significance to the repository and its design.

  11. Origin of Small Tectonic Plates

    NASA Astrophysics Data System (ADS)

    Mallard, C.; Coltice, N.; Seton, M.; Müller, D.; Tackley, P.

    2015-12-01

    The plate tectonic theory allowed to split the Earth surface into 6 (Le Pichon 1968) to 52 tectonic plates (Bird 2003). These plates are separated into two groups: the first of 7 large plates and the second of numerous smaller plates (Morra et al 2013). Previous studies using the reconstruction of the past 200 My, suggest that the size of large plates is driven by mantle flow. But the tools employed are descriptive (Morra et al 2013, Sornette and Pisarenko 2003), hence ignoring forces and physical principles within the lithosphere and the mantle. The processes at the origin of small plates remain unknown. We developed a new approach to explain the plate sizes. We demonstrate that the physics of convection drives it. We applied plate tectonics theory on 3D spherical convection models generating plate-like motions, which give access to a complete survey of data: velocities, viscosity and heat flow. Our data show that (1) the large plates depend on the dominating scale of the convective flow due to the initiation or the shutdown of subductions; (2) the smaller plates are generated thanks to large variability of regional stresses along subduction zone by slab pull and suction influenced by the geometry of trenches. Our results are consistent with the quick reorganizations of back-arc basins occuring synchronously with the modification of subduction zones geometry around the Pacific plate (Sdrolias et al 2004). Hence, we conclude that (1) the decreasing number of small plates in the plate reconstructions back in time is an artifact induced by their short lifetime, that is why they are artificially ignored; (2) the geometry of past trenches is simplified leading to an underestimation of the length of subduction zones.

  12. Late-Variscan Tectonic Inheritance and Salt Tectonics Interplay in the Central Lusitanian Basin

    NASA Astrophysics Data System (ADS)

    Nogueira, Carlos R.; Marques, Fernando O.

    2017-04-01

    Tectonic inheritance and salt structures can play an important role in the tectono-sedimentary evolution of basins. The Alpine regional stress field in west Iberia had a horizontal maximum compressive stress striking approximately NNW-SSE, related to the Late Miocene inversion event. However, this stress field cannot produce a great deal of the observed and mapped structures in the Lusitanian Basin. Moreover, many observed structures show a trend similar to well-known basement fault systems. The Central Lusitanian basin shows an interesting tectonic structure, the Montejunto structure, generally assigned to this inversion event. Therefore, special attention was paid to: (1) basement control of important observed structures; and (2) diapir tectonics (vertical maximum compressive stress), which can be responsible for significant vertical movements. Based on fieldwork, tectonic analysis and interpretation of geological maps (Portuguese Geological Survey, 1:50000 scale) and geophysical data, our work shows: (1) the Montejunto structure is a composite structure comprising an antiform with a curved hinge and middle Jurassic core, and bounding main faults; (2) the antiform can be divided into three main segments: (i) a northern segment with NNE-SSW trend showing W-dipping bedding bounded at the eastern border by a NNE-SSW striking fault, (ii) a curved central segment, showing the highest topography, with a middle Jurassic core and radial dipping bedding, (iii) a western segment with ENE-WSW trend comprising an antiform with a steeper northern limb and periclinal termination towards WSW, bounded to the south by ENE-WSW reverse faulting, (3) both fold and fault trends at the northern and western segments are parallel to well-known basement faults related to late-Variscan strike-slip systems with NNE-SSW and ENE-WSW trends; (4) given the orientation of Alpine maximum compressive stress, the northern segment border fault should be mostly sinistral strike-slip and the western

  13. Tectonic deformation in southern California

    NASA Technical Reports Server (NTRS)

    Jackson, David D.

    1993-01-01

    Our objectives were to use modem geodetic data, especially those derived from space techniques like Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and the Global Positioning System (GPS) to infer crustal deformation in southern California and relate it to plate tectonics and earthquake hazard. To do this, we needed to collect some original data, write computer programs to determine positions of survey markers from geodetic observables, interpret time dependent positions in terms of velocity and earthquake caused episodic displacements, and construct a model to explain these velocities and displacements in terms of fault slip and plate movements.

  14. Continental margin tectonics - Forearc processes

    SciTech Connect

    Lundberg, N.; Reed, D.L. )

    1991-01-01

    Recent studies of convergent plate margins and the structural development of forearc terranes are summarized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the geometry of accretionary prisms (Coulomb wedge taper and vertical motion in response to tectonic processes), offscraping vs underplating or subduction, the response to oblique convergence, fluids in forearc settings, the thermal framework and the effects of fluid advection, and serpentinite seamounts. Also included is a comprehensive bibliography for the period.

  15. Tectonics

    NASA Image and Video Library

    2015-09-04

    The graben and collapse features in this image are part of Ceraunius Fossae, which is located south of Alba Mons. Orbit Number: 60406 Latitude: 27.0278 Longitude: 249.29 Instrument: VIS Captured: 2015-07-27 14:05 http://photojournal.jpl.nasa.gov/catalog/PIA19767

  16. A Preliminary Study of Seismic Risk in the Pyongyang Area, North Korea

    NASA Astrophysics Data System (ADS)

    Kang, S. Y.; Kim, K. H.

    2016-12-01

    Small and large earthquakes have occurred according to the historical and instrumental records in the Korean Peninsula. Results of the GIS spatial analyst using historical and instrumental records indicate high point (earthquake) density in Pyongyang metropolitan area in North Korea, and southern areas in South Korea. Apparently, Pyongyang metropolitan area, the capital of North Korea, is exposed to large risks due to natural hazards including earthquakes. Assuming a magnitude 6.7 scenario earthquake, which was experienced in A.D. 502 in the area, 51.1% of the Pyongyang area will experience 0.24g or higher shaking. Approximately 14.8 % of the population in North Korea has been evacuated due to disasters between 1999 and 2008. This is significantly higher than that of South Korea (62 times higher) in the same period. It demonstrates that North Korea is in poorer environment and may have lesser competencies to handle the crisis of hazard than that of South Korea. Results of the study provide a significant information in laying out the earthquake disaster assessment system.

  17. Analogue scale modelling of extensional tectonic processes using a large state-of-the-art centrifuge

    NASA Astrophysics Data System (ADS)

    Park, Heon-Joon; Lee, Changyeol

    2017-04-01

    Analogue scale modelling of extensional tectonic processes such as rifting and basin opening has been numerously conducted. Among the controlling factors, gravitational acceleration (g) on the scale models was regarded as a constant (Earth's gravity) in the most of the analogue model studies, and only a few model studies considered larger gravitational acceleration by using a centrifuge (an apparatus generating large centrifugal force by rotating the model at a high speed). Although analogue models using a centrifuge allow large scale-down and accelerated deformation that is derived by density differences such as salt diapir, the possible model size is mostly limited up to 10 cm. A state-of-the-art centrifuge installed at the KOCED Geotechnical Centrifuge Testing Center, Korea Advanced Institute of Science and Technology (KAIST) allows a large surface area of the scale-models up to 70 by 70 cm under the maximum capacity of 240 g-tons. Using the centrifuge, we will conduct analogue scale modelling of the extensional tectonic processes such as opening of the back-arc basin. Acknowledgement This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (grant number 2014R1A6A3A04056405).

  18. Present status and issues of school nutrition programs in Korea.

    PubMed

    Yoon, Jihyun; Kwon, Sooyoun; Shim, Jae Eun

    2012-01-01

    School nutrition programs are essential for children's long-term nutrition and health promotion. The last decade has been the most dramatic years in the history of school nutrition programs in Korea. The percentage of schools serving school lunches reached almost 100% in 2003. In 2006, School Meals Act was significantly revised after serial outbreaks of food-borne illness among students having eaten school lunches. The safety and nutritional quality of school meals had remained as the biggest issue until the middle of 2000s, and then eco-friendly and universal free school lunches have become the main issues related to school meal service and are still under debate. Implementation of the Nutrition Teacher System in 2006 was the turning point of school-based nutrition education in Korea. In addition, two new laws, Special Act on Children's Dietary Life Safety Management of 2008 and Dietary Life Education Support Act of 2009, started to make meaningful changes in school nutrition environment and practices. The next decade is expected to be very critical in the development of school nutrition programs in Korea as the new systems and laws are to be settled. Significant effort is needed from both the academia and the field to make the related issues to be debated and answered to progressive direction for the school nutrition programs in Korea.

  19. South Korea's renewed focus on space weather

    NASA Astrophysics Data System (ADS)

    Ahn, Byung-Ho

    2011-10-01

    Nearly 1000 years before European scientists David Fabricius and Galileo Galilei made historic observations of sunspots, royal astronomers in Korea were recording their observations of blemishes on the Sun. Sunspot records appeared as early as 640 C.E. in Korea [Yang et al., 1998], and records with statistically significant populations of data have been available since 1105 C.E. during the Goryeo dynasty (918-1392). The records are quite meticulous. For example, one entry dated 1151 in the annals of the Goryeo dynasty says, "There is a black spot in the sun as large as an egg" (Goryeo-Sa, 1451). At that time, sunspots were categorized according to size: plum, egg, peach, or pear. In Goryeo-Sa, various celestial phenomena such as solar eclipses, comets, novae, meteors, etc., were also recorded. Along with sunspots, aurorae were carefully described in several Korean chronicles, including Goryeo-Sa. Descriptions of aurorae, commonly referred to as "red energy," include their color, shape, motion, and distribution. For example, a description written in 1770 reads, "It spread across the sky like a piece of silk cloth and then dispersed" [Chanjipcheong, 1908; Park, 2008]. Applying a power spectrum analysis technique to all sunspot and aurora records during the Goryeo dynasty, Yang et al. [1998] and Lee et al. [2005] have shown 10.5-year and 97-year cycles for the sunspot records and 10-year and 87-year cycles for the aurora records.

  20. The treatment of tuberculosis in South Korea.

    PubMed

    Seung, K J; Bai, G H; Kim, S J; Lew, W J; Park, S K; Kim, J Y

    2003-10-01

    South Korea's complex system of tuberculosis control has never been fully described. The prevalence of tuberculosis has dropped dramatically since 1965, partly because of farsighted governmental policy that provided low-cost, accessible tuberculosis treatment to the entire population. Within the tuberculosis control system, public and private sector entities provide a wide variety of treatment options. The National Tuberculosis Program focuses on improving cure rates for new cases, while the private sector has taken more of a role in the treatment of drug-resistant tuberculosis and other types of complicated cases. There has been a decrease in drug-resistant tuberculosis since 1980 for multiple reasons, including increased cure rates from the introduction of rifampin-based regimens, improved nutrition and living standards, and the treatment of drug-resistant cases in the private sector. Multidrug-resistant tuberculosis, however, still poses a significant threat to public health. The limited outcomes data that exist in South Korea for multidrug-resistant tuberculosis treatment suggest that cure rates are low and failure and abandonment rates are high. New public health measures are needed to improve the control of multidrug-resistant tuberculosis.

  1. Preliminary Estimation of Postseismic Deformation Parameters from Continuous GPS Data in Korea Peninsula and Ieodo after the 2011 Tohoku-Oki MW9.0 Earthquake

    NASA Astrophysics Data System (ADS)

    Aris, W. A. W.; Musa, T. A.; Lee, H.; Choi, Y.; Yoon, H.

    2016-09-01

    This paper describes utilization of GPS data in Korea Peninsula and IEODO ocean research station for investigation of postseismic deformation characteristic after the 2011 Tohoku-oki Mw9.0 Earthquake. Analytical logarithmic and exponential functions were used to evaluate the postseismic deformation parameters. The results found that the data in Korea Peninsula and IEODO during periods of mid-2011 - mid-2014 are fit better using logarithmic function with deformation decay at 134.5 ±0.1 days than using the exponential function. The result also clearly indicates that further investigation into postseismic deformation over longer data span should be taken into account to explain tectonic deformation over the region.

  2. Korea and the Yellow Sea

    NASA Image and Video Library

    2017-09-27

    NASA image acquired September 24, 2012 City lights at night are a fairly reliable indicator of where people live. But this isn’t always the case, and the Korean Peninsula shows why. As of July 2012, South Korea’s population was estimated at roughly 49 million people, and North Korea’s population was estimated at about half that number. But where South Korea is gleaming with city lights, North Korea has hardly any lights at all—just a faint glimmer around Pyongyang. On September 24, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of the Korean Peninsula. This imagery is from the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as gas flares, auroras, wildfires, city lights, and reflected moonlight. The wide-area image shows the Korean Peninsula, parts of China and Japan, the Yellow Sea, and the Sea of Japan. The white inset box encloses an area showing ship lights in the Yellow Sea. Many of the ships form a line, as if assembling along a watery border. Following the 1953 armistice ending the Korean War, per-capita income in South Korea rose to about 17 times the per-capital income level of North Korea, according to the U.S. Central Intelligence Agency. Worldwide, South Korea ranks 12th in electricity production, and 10th in electricity consumption, per 2011 estimates. North Korea ranks 71st in electricity production, and 73rd in electricity consumption, per 2009 estimates. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott. Instrument: Suomi NPP - VIIRS Credit: NASA Earth Observatory Click here to view all of the Earth at Night 2012

  3. Characteristics of Drug Resistant Tuberculosis in Sanatoria of North Korea

    PubMed Central

    2017-01-01

    Although several reports about drug-resistant tuberculosis (TB) in North Korea have been published, a nationwide surveillance on this disease remains to be performed. This study aims to analyze the drug resistance patterns of Mycobacterium tuberculosis among the patients in the sanatoria of North Korea, especially during the period when second-line drugs (SLDs) had not yet been officially supplied to this country. The Eugene Bell Foundation (EBF) transferred 947 sputum specimens obtained from 667 patients from 2007 to 2009 to the Clinical Research Center, Masan National Tuberculosis Hospital (MNTH), South Korea. Four hundred ninety-two patients were culture positive for TB (73.8%). Drug susceptibility test (DST) was performed for the bacilli isolated from 489 patients. Over 3 quarters of the cases (76.9%) were multidrug-resistant (MDR)-TB. Additionally, 2 patients had extremely drug-resistant (XDR)-TB. Very high resistance to first-line drugs and low resistance to fluoroquinolones (FQs) and injectable drugs (IDs) except for streptomycin (S) were detected. A small but significant regional variation in resistance pattern was observed. Big city regions had higher rate of MDR-TB, higher resistance to FQs and IDs than relatively isolated regions. In conclusion, significant number of drug-resistant TB was detected in North Korean sanatoria, and small but significant regional variations in resistance pattern were noticeable. However, the data in this study do not represent the nationwide drug resistance pattern in North Korea. Further large-scale evaluations are necessary to estimate the resistance pattern of TB in North Korea. PMID:28581266

  4. Characteristics of Drug Resistant Tuberculosis in Sanatoria of North Korea.

    PubMed

    Jung, Jihee; Jegal, Yangjin; Ki, Moran; Shin, Young Jeon; Kim, Cheon Tae; Shim, Tae Sun; Sung, Nackmoon

    2017-07-01

    Although several reports about drug-resistant tuberculosis (TB) in North Korea have been published, a nationwide surveillance on this disease remains to be performed. This study aims to analyze the drug resistance patterns of Mycobacterium tuberculosis among the patients in the sanatoria of North Korea, especially during the period when second-line drugs (SLDs) had not yet been officially supplied to this country. The Eugene Bell Foundation (EBF) transferred 947 sputum specimens obtained from 667 patients from 2007 to 2009 to the Clinical Research Center, Masan National Tuberculosis Hospital (MNTH), South Korea. Four hundred ninety-two patients were culture positive for TB (73.8%). Drug susceptibility test (DST) was performed for the bacilli isolated from 489 patients. Over 3 quarters of the cases (76.9%) were multidrug-resistant (MDR)-TB. Additionally, 2 patients had extremely drug-resistant (XDR)-TB. Very high resistance to first-line drugs and low resistance to fluoroquinolones (FQs) and injectable drugs (IDs) except for streptomycin (S) were detected. A small but significant regional variation in resistance pattern was observed. Big city regions had higher rate of MDR-TB, higher resistance to FQs and IDs than relatively isolated regions. In conclusion, significant number of drug-resistant TB was detected in North Korean sanatoria, and small but significant regional variations in resistance pattern were noticeable. However, the data in this study do not represent the nationwide drug resistance pattern in North Korea. Further large-scale evaluations are necessary to estimate the resistance pattern of TB in North Korea. © 2017 The Korean Academy of Medical Sciences.

  5. Analysis of tectonic features in US southwest from Skylab photographs

    NASA Technical Reports Server (NTRS)

    Abdel-Gawad, M. (Principal Investigator); Tubbesing, L.

    1975-01-01

    The author has identified the following significant results. Skylab photographs were utilized to study faults and tectonic lines in selected areas of the U.S. Southwest. Emphasis was on elements of the Texas Zone in the Mojave Desert and the tectonic intersection in southern Nevada. Transverse faults believed to represent the continuation of the Texas Zone were found to be anomalous in strike. This suggests that the Mojave Desert block was rotated counterclockwise as a unit with the Sierra Nevada. Left-lateral strike-slip faults in Lake Mead area are interpreted as elements of the Wasatch tectonic zone; their anomalous trend indicates that the Lake Mead area has rotated clockwise with the Colorado Plateau. A tectonic model relating major fault zones to fragmentation and rotation of crustal blocks was developed. Detailed correlation of the high resolution S190B metric camera photographs with U-2 photographs and geologic maps demonstrates the feasibility of utilizing S190B photographs for the identification of geomorphic features associated with recent and active faults and for the assessment of seismic hazards.

  6. Pargo Chasma and its relationship to global tectonics

    NASA Technical Reports Server (NTRS)

    Ghail, R. C.

    1993-01-01

    Pargo Chasma was first identified on Pioneer Venus data as a 10,000 km long lineation extending from Atla Regio in the north terminating in the plains south of Phoebe Regio. More recent Magellan data have revealed this feature to be one of the longest chains of coronae so far identified on the planet. Stofan et al have identified 60 coronae and 2 related features associated with this chain; other estimates differ according to the classification scheme adopted, for example Head et al. identify only 29 coronae but 43 arachnoids in the same region. This highlights one of the major problems associated with the preliminary mapping of the Magellan data: there has been an emphasis on identifying particular features on Venus without a universally accepted scheme to classify those features. Nevertheless, Pargo Chasma is clearly identified as a major tectonic belt of global significance. Together with the Artemis-Atla-Beta tectonic zone and the Beta-Phoebe rift belt, Pargo Chasma defines a region on Venus with an unusually high concentration of tectonic and volcanic features. Thus, an understanding of the processes involved in the formation of Pargo Chasma may lend significant insight into the evolution of the region and the planet as a whole. I have produced a detailed 1 to 10 million scale map of Pargo Chasma and the surrounding area from preliminary USGS controlled mosaiced image maps of Venus constructed from Magellan data. In view of the problems highlighted above in relation the efforts already made at identifying a particular set of features I have mapped the region purely on the basis of the geomorphology visible in the magellan data without any attempt at identifying a particular set or class of features. Thus, the map produced distinguishes between areas of different brightness and texture. This has the advantage of highlighting the tectonic fabric of Pargo Chasma and clearly illustrates the close inter-relationship between individual coronae and the surrounding

  7. Clinical Features of Re-Emerging Hepatitis A: An Analysis of Patients Hospitalized during an Urban Epidemic in Korea

    PubMed Central

    Choi, Hee Kyoung; Song, Young Goo; Kim, Chang Oh; Shin, So Youn; Chin, Bum Sik; Han, Sang Hoon; Jin, Sung Joon; Chae, Yun Tae; Baek, Ji-Hyeon; Kim, Sun Bean; Kim, Do Young; Park, Jun Yong; Kim, June Myung

    2011-01-01

    From April 2008 to November 2008, many cases of hepatitis A were reported in Seoul and Gyeonggi Province in Korea. Furthermore, the rate of severe or fulminant hepatitis have significantly increased during the latest epidemic (13.4% vs. 5.2%, p=0.044). Therefore, widespread use of vaccine is warranted to reduce the burden of hepatitis A in Korea. PMID:21623615

  8. Genetic diversity and population structure of Raffaelea quercus-mongolicae, a fungus associated with oak mortality in South Korea

    Treesearch

    M. -S. Kim; P. A. Hohenlohe; K. -H. Kim; S. -T. Seo; Ned Klopfenstein

    2016-01-01

    Raffaelea quercus-mongolicae is a fungus associated with oak wilt and deemed to cause extensive oak mortality in South Korea. Since the discovery of this fungus on a dead Mongolian oak (Quercus mongolica) in 2004, the mortality continued to spread southwards in South Korea. Despite continued expansion of the disease and associated significant impacts on forest...

  9. Magmatic-Tectonic Evolution of Tharsis

    NASA Technical Reports Server (NTRS)

    Anderson, R. C.; Dohm, J. M.

    2000-01-01

    The tectonic history of the western hemisphere region of Mars was dominated by the formation of the Tharsis rise. In this study, we identify local centers of tectonic activity and examine how each of the centers fit into the overall evolution of the Tharsis region.

  10. Plate Tectonic Cycle. K-6 Science Curriculum.

    ERIC Educational Resources Information Center

    Blueford, J. R.; And Others

    Plate Tectonics Cycle is one of the units of a K-6 unified science curriculum program. The unit consists of four organizing sub-themes: (1) volcanoes (covering formation, distribution, and major volcanic groups); (2) earthquakes (with investigations on wave movements, seismograms and sub-suface earth currents); (3) plate tectonics (providing maps…

  11. Tectonic models for Yucca Mountain, Nevada

    USGS Publications Warehouse

    O'Leary, D. W.

    2006-01-01

    Performance of a high-level nuclear waste repository at Yucca Mountain hinges partly on long-term structural stability of the mountain, its susceptibility to tectonic disruption that includes fault displacement, seismic ground motion, and igneous intrusion. Because of the uncertainty involved with long-term (10,000 yr minimum) prediction of tectonic events (e.g., earthquakes) and the incomplete understanding of the history of strain and its mechanisms in the Yucca Mountain region, a tectonic model is needed. A tectonic model should represent the structural assemblage of the mountain in its tectonic setting and account for that assemblage through a history of deformation in which all of the observed deformation features are linked in time and space. Four major types of tectonic models have been proposed for Yucca Mountain: a caldera model; simple shear (detachment fault) models; pure shear (planar fault) models; and lateral shear models. Most of the models seek to explain local features in the context of well-accepted regional deformation mechanisms. Evaluation of the models in light of site characterization shows that none of them completely accounts for all the known tectonic features of Yucca Mountain or is fully compatible with the deformation history. The Yucca Mountain project does not endorse a preferred tectonic model. However, most experts involved in the probabilistic volcanic hazards analysis and the probabilistic seismic hazards analysis preferred a planar fault type model. ?? 2007 Geological Society of America. All rights reserved.

  12. Life with and Life without Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Lenardic, A.; Hoeink, T.; Jellinek, M.; Johnson, C. L.; Cowan, N. B.; Pierrehumbert, R.; Stamenkovic, V.; O'Neill, C.; Dasgupta, R.

    2014-12-01

    The long standing notion that plate tectonics is key to planetary habitability is critically evaluated. The purported necessity of plate tectonics for planetary habitability is tied to volatile cycling, atmosphere retention, and carbon burial. Plate tectonics is not unique in allowing for cycling of volatiles between the interior of a planet and its atmosphere. Volcanism can be maintained on a single plate planet over geologic time scales and several non-plate tectonic recycling mechanisms are viable on such a planet. The frequency and efficiency of these modes of volatile recycling and volcanism are critical to evaluating whether they are sufficient to stabilize climate. An episodic mode of a volcanism and subduction also has the potential to provide the level of volatile cycling needed to maintain habitability. We combine solid planet models of degassing and regassing with climate, surface processes, and carbon sequestration models to determine the level to which habitable conditions can be maintained in the absence of plate tectonics. We also review arguments that the Earth operated in a different tectonic mode over its initial 2-3 billion years of geologic evolution, a time period over which the planet was habitable. Collectively our results suggests that habitable conditions can exist independent of the tectonic mode of a planet. However, O-rich atmospheres and complex life might require continuous recycling processes and ocean floor uplift to bury carbon onto stable platforms as provided by plate tectonics.

  13. Magmatic-Tectonic Evolution of Tharsis

    NASA Technical Reports Server (NTRS)

    Anderson, R. C.; Dohm, J. M.

    2000-01-01

    The tectonic history of the western hemisphere region of Mars was dominated by the formation of the Tharsis rise. In this study, we identify local centers of tectonic activity and examine how each of the centers fit into the overall evolution of the Tharsis region.

  14. Plate Tectonic Cycle. K-6 Science Curriculum.

    ERIC Educational Resources Information Center

    Blueford, J. R.; And Others

    Plate Tectonics Cycle is one of the units of a K-6 unified science curriculum program. The unit consists of four organizing sub-themes: (1) volcanoes (covering formation, distribution, and major volcanic groups); (2) earthquakes (with investigations on wave movements, seismograms and sub-suface earth currents); (3) plate tectonics (providing maps…

  15. Mapping Seafloor Tectonics from Space

    NASA Astrophysics Data System (ADS)

    Sandwell, D. T.; Smith, W. H.

    2005-12-01

    Our current understanding of the topography and tectonics of the ocean basins is largely derived from dense satellite altimeter measurements of the marine gravity field combined with sparse geophysical measurements from research vessels. First generation satellite altimetry was initiated in the 1970s by NASA with the Skylab and GEOS-3 missions, followed by the brief but highly successful Seasat mission of 1978. Seasat provided the first global view of the marine gravity field, well illustrated by Bill Haxby's maps of the early 1980s. It is difficult to express the excitement in the scientific community when the global signatures of the postulated ridges, transforms, and subduction zones were revealed. Moreover, Seasat proved that non-repeat orbit altimetry was the obvious way to map the ocean basins and the US Navy quickly developed Geosat in 1985 to finish the job. For 10 years the Geosat data remained classified until ESA's ERS-1 duplicated the secret information. The sudden availability of dense measurements from these second generation altimeters (Geosat and ERS-1) is perhaps the most important ocean science observation in the last two decades. These data provided not only a spectacular confirmation of plate tectonics but also partly revealed smaller-scale structures including thousands of seamounts, propagating rifts, ridge jumps, and global-scale variations in seafloor roughness. In addition, the dense gravity information was combined with sparse ship soundings to construct global bathymetry maps at ~10 km resolution - a great improvement over hand-drawn maps but still far worse than our current maps of Mars, Venus, and the Moon. While these data filled a huge gap in our understanding of the ocean basins, they also triggered a thirst for more. Third generation altimeters with improved range precision are on the horizon. The scientific rationale for a factor of 5 improvement in altimeter precision spans three broad areas of earth science: one, resolving the

  16. North Korea: Terrorism List Removal

    DTIC Science & Technology

    2009-04-15

    Second- 28 Yi Sang-il and Chin Se-ku. Yongbyon nuclear facility can be disabled within...The White House, Roundtable Interview of the President by Foreign Print Media, August 30, 3007. 32 Choe Sang- hun and David E. Sanger, North Korea...2006 through the spring of 2007 to smuggle conventional arms, including machine guns , automatic rifles, and anti-tank rocket launchers, to the

  17. North Korea: Terrorism List Removal?

    DTIC Science & Technology

    2008-07-10

    and Chin Se-ku. Yongbyon nuclear facility can be disabled within a year. JongAng Ilbo (internet version), March 13, 2007. Korea’s nuclear programs and...the President by Foreign Print Media, August 30, 3007. 30 Choe Sang- hun and David E. Sanger, North Korea claims U.S. will remove sanctions...including machine guns , automatic rifles, and anti-tank rocket launchers, to the Tamil Tigers in Sri Lanka. The Sri Lankan navy intercepted and

  18. Foreign Assistance to North Korea

    DTIC Science & Technology

    2010-03-12

    Report Documentation Page Form ApprovedOMB No . 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per...clarified that “ no funds are provided in this act for energy-related assistance for North Korea.” The House Appropriations Committee report on the other...and Diplomacy, by Larry A. Niksch, and CRS Report RL34256, North Korea’s Nuclear Weapons: Technical Issues, by Mary Beth Nikitin. 22 See CRS Report

  19. Foreign Assistance to North Korea

    DTIC Science & Technology

    2009-09-09

    Documentation Page Form ApprovedOMB No . 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response...North Korean denuclearization efforts. Later in the report , the Committee clarifies that “ no funds are provided in this act for energy-related...Nuclear Weapons: Technical Issues, by Mary Beth Nikitin. 19 See CRS Report RL30613, North Korea: Terrorism List Removal, by Larry A. Niksch. 20

  20. U.S.-South Korea Relations

    DTIC Science & Technology

    2013-04-26

    News , December 1, 2012. U.S.- South Korea Relations Congressional Research Service 7 • China’s rising influence in ...entered into force and will be eliminated completely in the fifth year of the agreement. South Korea also agreed to allow U.S.-based car manufacturers to...sell in South Korea up to 25,000 cars per year per manufacturer as long as they met U.S. safety and environmental standards. This

  1. Standardization of ABO antibody titer measurement at laboratories in Korea.

    PubMed

    Lim, Young Ae; Kang, Seon Joo

    2014-11-01

    Measurement of the ABO antibody (Ab) titer is important in ABO-incompatible transplantation. However, to the best of our knowledge, no standard protocol or external survey program to measure the ABO Ab titer has been established in Korea. We investigated the current status of ABO Ab titer measurements at various laboratories in Korea and the impact of the protocol provided to reduce interlaboratory variations in the methods and results of ABO Ab titers. The Korean external quality assessment of blood bank laboratories sent external survey samples with a questionnaire to 68 laboratories across Korea for the measurement of ABO Ab titers in May 2012. After 6 months, a second set of survey samples were sent with a standard protocol to 53 of the previously surveyed laboratories. The protocol recommended incubation at room temperature only and use of the indirect antihuman globulin method for the tube test as well as and the column agglutination test (CAT). Several interlaboratory variations were observed in the results, technical procedures, and methods selected for measurement. We found that 80.4% laboratories hoped to change their protocol to the provisional one. Additionally, CAT showed significantly lower variation among laboratories (P=0.006) than the tube test. Our study provides baseline data regarding the current status of ABO Ab titer measurement in Korea. The standard protocol and external survey were helpful to standardize the technical procedures and select methods for ABO Ab titer measurement.

  2. Assessment of trace metals in four bird species from Korea.

    PubMed

    Kim, Jungsoo; Oh, Jong-Min

    2013-08-01

    In birds, heavy metal concentrations are influenced by diet intake, migratory pattern, and residence time. In the present study, heavy metal concentrations (in microgram per gram dry weight) were measured in livers of four bird species from Korea. Iron concentrations were greater in Eurasian Woodcocks (Scolopax rusticola) than in Grey Herons (Ardea cinerea), Little Egrets (Egretta garzetta), and Schrenck's Bitterns (Ixobrychus eurhythmus). Copper concentrations in Grey Herons were significantly higher than in other species. Lead concentrations were greater in Schrenck's Bitterns and Eurasian Woodcocks than in Grey Herons and Little Egrets. Eurasian Woodcocks had higher cadmium concentrations than in other species. Zinc and manganese concentrations did not differ among species. Iron, zinc, manganese, and copper concentrations from this study were within the range of other Korean bird studies, and these concentrations were far below toxic levels. Cadmium and lead accumulation trends in each species were different, and the results might be associated with their migration pattern and residence time in Korea. Grey Herons, Little Egrets, and Schrenck's Bitterns are usually summer visitors, and Eurasian Woodcocks are passage migrants. But herons and egrets were collected in spring, autumn, and winter, but not during breeding season. They might be residents, so they could more reflect Korean cadmium and lead contaminations than Schrenck's Bitterns. However, Eurasian Woodcocks could more reflect habitats outside Korea because of their short staying time in Korea.

  3. Hotspot evolution and Venusian tectonic style

    NASA Astrophysics Data System (ADS)

    McGill, George E.

    1994-11-01

    Because hotspots represent an important manifestation of heat loss on Venus, their geological evolution is of fundamental importance for any attempt to understand Venusian tectonics. Eistla Regio is an approximately 7500-km-long, moderately elevated region inferred to overlie one or more large mantle upwellings or hotspots. It also contains many shield volcanoes and coronae believed due to the rise of thermal plumes in the mantle. Central Eistla Regio includes two large volcanoes, Sappho and Anala, and several coronae in close proximity. Detailed mapping in this region results in two conclusions of tectonic significance: (1) Sappho and Anala occur near the intersection of two major extensional deformation zones, and (2) the coronae are older than the large volcanoes. Several of the coronae occur as a chain along Guor Linea, one of the major extensional deformation zones. Stratigraphic relationships indicate that the coronae began forming very soon after the emplacement of the widespread regional plains materials. Thus Central Eistla Regio was the site of a swarm of plumes that first formed coronae and then later formed shield volcanoes. The expected result of such a swarm would be thermal thinning of the elastic lithosphere with time. However, model results, geological observations, and gravity data suggest that the change from coronae to shield volcanoes was accompanied by a thickening of the lithosphere with time. This thickening is interpreted to be the result of global cooling of the lithosphere following the most recent episode of near-global resurfacing. The global cooling must have occurred faster than local heating of the lithosphere due to the impingement of thermal plumes.

  4. Gravity and tectonic patterns of Mercury

    NASA Astrophysics Data System (ADS)

    Matsuyama, I.; Nimmo, F.

    2008-12-01

    We consider the effect of tidal deformation, spin-orbit resonance, non-zero eccentricity, despinning, and reorientation on the global-scale gravity, shape, and tectonic patterns of planetary bodies. Large variations of the gravity and shape coefficients from the synchronous rotation and zero eccentricity values, J2/C22=10/3 and (b-c)/(a-c)=1/4, arise due to non-synchronous rotation and non-zero eccentricity even in the absence of reorientation or despinning. Reorientation or despinning induce additional variations. As an illustration of this theory, we consider the specific example of Mercury. The large gravity coefficients estimated from the Mariner 10 flybys cannot be attributed to the Caloris basin alone since the required mass excess in this case would have caused Caloris to migrate to one of Mercury's hot poles. Similarly, a large remnant bulge due to a smaller semimajor axis and spin-orbit resonance can be dismissed since the required semimajor axis is unphysically small (< 0.1 AU). Reorientation of a large remnant bulge recording an epoch of faster rotation (without significant semimajor axis variations) can explain the large gravity coefficients. This requires initial rotation rates > 20 times the present value and a positive gravity anomaly associated with Caloris capable of driving 10-45° equatorward reorientation. The required gravity anomaly can be explained by infilling of the basin with material of thicknesses > 7 km, or an annulus of volcanic plains emplaced around the basin with annulus width ~ 1200 km and fill thicknesses > 2 km. The predicted tectonic pattern due to these despinning and reorientation scenarios and radial contraction is in good agreement with the observed lobate scarp pattern.

  5. Hotspot evolution and Venusian tectonic style

    NASA Technical Reports Server (NTRS)

    Mcgill, George E.

    1994-01-01

    Because hotspots represent an important manifestation of heat loss on Venus, their geological evolution is of fundamental importance for any attempt to understand Venusian tectonics. Eistla Regio is an approximately 7500-km-long, moderately elevated region inferred to overlie one or more large mantle upwellings or hotspots. It also contains many shield volcanoes and coronae believed due to the rise of thermal plumes in the mantle. Central Eistla Regio includes two large volcanoes, Sappho and Anala, and several coronae in close proximity. Detailed mapping in this region results in two conclusions of tectonic significance: (1) Sappho and Anala occur near the intersection of two major extensional deformation zones, and (2) the coronae are older than the large volcanoes. Several of the coronae occur as a chain along Guor Linea, one of the major extensional deformation zones. Stratigraphic relationships indicate that the coronae began forming very soon after the emplacement of the widespread regional plains materials. Thus Central Eistla Regio was the site of a swarm of plumes that first formed coronae and then later formed shield volcanoes. The expected result of such a swarm would be thermal thinning of the elastic lithosphere with time. However, model results, geological observations, and gravity data suggest that the change from coronae to shield volcanoes was accompanied by a thickening of the lithosphere with time. This thickening is interpreted to be the result of global cooling of the lithosphere following the most recent episode of near-global resurfacing. The global cooling must have occurred faster than local heating of the lithosphere due to the impingement of thermal plumes.

  6. Serious fungal infections in Korea.

    PubMed

    Huh, K; Ha, Y E; Denning, D W; Peck, K R

    2017-02-04

    Information on the incidence and prevalence of fungal infections is of critical value in public health policy. However, nationwide epidemiological data on fungal infections are scarce, due to a lack of surveillance and funding. The objective of this study was to estimate the disease burden of fungal infections in the Republic of Korea. An actuarial approach using a deterministic model was used for the estimation. Data on the number of populations at risk and the frequencies of fungal infections in those populations were obtained from national statistics reports and epidemiology papers. Approximately 1 million people were estimated to be affected by fungal infections every year. The burdens of candidemia (4.12 per 100,000), cryptococcal meningitis (0.09 per 100,000), and Pneumocystis pneumonia (0.51 per 100,000) in South Korea were estimated to be comparable to those in other countries. The prevalence of chronic pulmonary aspergillosis (22.4 per 100,000) was markedly high, probably due to the high burden of tuberculosis in Korea. The low burdens of allergic bronchopulmonary aspergillosis (56.9 per 100,000) and severe asthma with fungal sensitization (75.1 per 100,000) warrant further study. Oral candidiasis (539 per 100,000) was estimated to affect a much larger population than noted in previous studies. Our work provides valuable insight on the epidemiology of fungal infections; however, additional studies are needed.

  7. Occupational Neurologic Disorders in Korea

    PubMed Central

    Jeong, Kyoung Sook; Yun, Yong-Hun; Oh, Myoung-Soon

    2010-01-01

    This article presents a schematic review of the clinical manifestations of occupational neurologic disorders in Korea and discusses the toxicologic implications of these conditions. Vascular encephalopathy, parkinsonism, chronic toxic encephalopathy, cerebellar dysfunction, peripheral neuropathy, and neurodegenerative diseases are common presentations of occupational neurotoxic syndromes in Korea. Few neurotoxins cause patients to present with pathognomic neurologic syndrome. Detailed neurologic examinations and categorization of the clinical manifestations of neurologic disorders will improve the clinical management of occupational neurologic diseases. Physicians must be aware of the typical signs and symptoms of possible exposure to neurotoxins, and they should also pay attention to less-typical, rather-vague symptoms and signs in workers because the toxicologic characteristics of occupational neurologic diseases in Korea have changed from typical patterns to less-typical or equivocal patterns. This shift is likely to be due to several years of low-dose exposure, perhaps combined with the effects of aging, and new types of possibly toxicant-related neurodegenerative diseases. Close collaboration between neurologists and occupational physicians is needed to determine whether neurologic disorders are work-related. PMID:20607045

  8. Brief Introduction on the Korea-China Collaborative Research on the Wide-angle Seismic Experiment of the Yellow Sea

    NASA Astrophysics Data System (ADS)

    Kim, J.; Kim, K. H.; Kim, H. J.; Hao, T.; Zhang, X.

    2016-12-01

    Small to moderate earthquakes occurred in the Yellow Sea, such as Seogyuckryulbi-do earthquake (ML 5.1, April 1, 2014) and Heuksan-do earthquake (ML 4.9, April 21, 2013). Although the earthquakes occurred in a region of apparent low seismicity, they attracted much attention for the seismic hazards and rose questions about the reevaluation the seismicity of the Yellow Sea. Although several tectonic models have been proposed from the observations in China and Korea, it is still not clear which one can answer the tectonic problem. Furthermore, the seismicity of the Yellow Sea has been rarely investigated since the region is located outside seismic networks. It is suspected that the seismicity of the region is related to basin boundary faults created by rifting and tectonic inverting. In order to evaluate earthquake hazard of the Yellow Sea, it is required to identify spatial distribution of the faults. In this study, a deep seismic profile was carried out using ocean bottom seismometers (OBS's) to investigate the crust and upper mantle structure beneath the Yellow Sea and their relationship with shallower structures. The deep seismic profile was conducted by M/V Discoverer and R/V Eardo from June 21 to July 3, 2016. The air-gun array of 6,640 cu. in. shot along the 405 km profile across the Yellow Sea, which was recorded by 31 OBS's at a 13.5 km spacing. Besides, 10 temporary land stations were also installed onshore along the profile. This Korea-China collaborative wide-angle seismic experiment was first time across the Yellow Sea. Through this study, it is expected that Korea and China would build a credible cooperation on the study of the Yellow Sea region in future, and it's helpful to verify previously proposed tectonic evolution models for northeastern Asia including the Yellow Sea.

  9. Growth of a tectonic ridge

    SciTech Connect

    Fleming, R.W.; Messerich, J.A.; Johnson, A.M.

    1997-12-31

    The 28 June 1992 Landers, California, earthquake of M 7.6 created an impressive record of surface rupture and ground deformation. Fractures extend over a length of more than 80 km including zones of right-lateral shift, steps in the fault zones, fault intersections and vertical changes. Among the vertical changes was the growth of a tectonic ridge described here. In this paper the authors describe the Emerson fault zone and the Tortoise Hill ridge including the relations between the fault zone and the ridge. They present data on the horizontal deformation at several scales associated with activity within the ridge and belt of shear zones and show the differential vertical uplifts. And, they conclude with a discussion of potential models for the observed deformation.

  10. Tethys geology and tectonics revisited

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1991-01-01

    Tethys, a medium sized icy satellite of Saturn, was imaged by both Voyager 1 and 2 spacecraft at sufficiently high resolution to allow some geologic analysis. One fairly complete and several brief descriptions of Tethys' geology have been given. Partial results are given herein of a new analysis of Tethys' geology done as part of a comparative tectonic and cryovolcanic study of the saturnian satellites. A new geologic sketch map of Tethys' north polar area is given. This map is based on a sequence of images transformed to a polar stereographic projection at the same scale. The images present the same area under different illuminations, each of which brings out different features. A new global map is in progress.

  11. Tectonics and ice sheet dynamics of West Antarctic margins

    NASA Astrophysics Data System (ADS)

    Gohl, Karsten

    2010-05-01

    An understanding of the glacial history of the Amundsen Sea Embayment (ASE) and Pine Island Bay (PIB) is essential for proposing models on the future development of the West Antarctic Ice Sheet. This requires an understanding of the tectonic history and knowledge of tectonic features such as lineaments, ridges, sills and basins, because basement morphology and inherited erosional features control the flow direction of ice-sheets and the influx of Circum-Polar Deep Water (CDW). This is an attempt to reconstruct the tectonic history with the aim to search for basement features and crustal boundaries which may be correlated to the flow and dynamics of the ice-sheet. The Amundsen Sea Embayment of West Antarctica is in a prominent location for a series of tectonic and magmatic events from Paleozoic to Cenozoic times. Seismic, magnetic and gravity data from the embayment and PIB reveal the crustal thickness and significant tectonic features. NE-SW trending magnetic and gravity anomalies and the thin crust indicate a former rift zone which was active during or in the run-up to the breakup process between Chatham Rise and West Antarctica before or at 90 Ma. NW-SE trending gravity and magnetic anomalies, following a prolongation of Peacock Sound, indicate the extensional southern boundary to the Bellingshausen Plate which was active between 79 and 61 Ma. It is likely that the prominent Pine Island Trough follows a structural boundary between the crustal blocks of Ellsworth Land and Marie Byrd Land. Data are shown from the ASE and PIB which can be interpreted in context with the reconstruction of the ice advance and retreat history in this area. Differences in the behaviour of the ice-sheet are shown to exist for the western and eastern parts of PIB due to basement structures affecting the inflow of CDW.

  12. Discriminating Tectonic Tremor from Magmatic Processes in Observationally Challenging Environments

    NASA Astrophysics Data System (ADS)

    Brown, J. R.; Beroza, G. C.

    2011-12-01

    Deep tectonic tremor is a long-duration, low amplitude signal that has been shown to consist of low frequency earthquakes (LFEs) on the plate interface in subduction zones. Detecting LFEs from tremor-like signals in subduction settings can be challenging due to the combination of volcanic seismicity and sparse station geometry. This is particularly true for island arcs such as the Alaska-Aleutian subduction zone where the islands are small and noise levels are high. We have detected and located LFEs within tremor signals along the Alaska-Aleutian Arc in four locations: Kodiak Island, Alaska Peninsula, eastern Aleutians, and the Andreanof Islands. In all areas, the LFEs are located 10-40 km trenchward of the volcanic chain at depths ranging from 45-70 km. Location errors are significant (+/- 20 km in depth) due to sparse station geometry such that there is the possibility that the tremor could be associated with nearby volcanoes. Since most documented volcanic tremor is located in the shallow crust, it can often be discriminated from tectonic tremor simply based on location. However, deep volcanic tremor has been documented in Hawaii to depths of 40 km and could be more widespread. In the Aleutian arc, deep long period events (DLPs), which are thought to result from the movement of magma and volatiles, have been located as deep as 45 km and sometimes resemble tremor-like signals. The spectral character is another potential discriminant. We compare the cepstra (Fourier transform of the logarithmic power spectrum of a time series) of the tectonic tremor-like signals/LFEs and DLPs associated with volcanoes. Source characteristics of DLPs (non-shear slip) and tectonic tremor/LFEs (shear slip) are distinct and should be noticeable in the cepstral domain. This approach of using tremor locations and cepstral analysis could be useful for detecting and differentiating tectonic tremor from deep volcanic processes in other island arcs as well.

  13. Tectonic Motion of Malaysia: Analysis from Years 2001 TO 2013

    NASA Astrophysics Data System (ADS)

    Gill, J.; Shariff, N. S.; Omar, K.; Amin, Z. M.

    2015-10-01

    This paper seeks to investigate the tectonic motion of Malaysia using the Malaysian Active GPS Station (MASS) and Malaysia Realtime Kinematic GNSS Network (MyRTKnet) data from years 2001 to 2013. GNSS data were processed using Bernese 5.0, and plotted as a time series; whereby the period before and after the 2004 Sumatra-Andaman mega earthquake are plotted separately. From the time series, episodic events and stable inter-seismic deformation period are analysed. The results indicate that the 2001- 2004 and 2008-2011 periods were free from episodic events; hence, chosen to depict the tectonic motion of Malaysia before and after 2004 Sumatra-Andaman earthquake, respectively. The motion had a major change in direction and rate, especially for East Malaysia and South Peninsular Malaysia. This indicates there exist a long-term post-seismic deformation due to the 2004 mega earthquake. Nonetheless, the 2008-2011 inter-seismic period is stable, and suitable to represent the current long-term tectonic motion of Malaysia: Peninsular and East Malaysia moves south-east, at an average velocity of 0.89 ±0.01 cm/yr south and 1.70 ±0.02 cm/yr east, and 1.06 ±0.01 cm/yr south and 2.50 ±0.02 cm/yr east, respectively. In addition, the co-seismic motion for the 2005 Nias, 2007 Bengkulu and 2012 Northern Sumatra earthquakes after the 2004 Sumatra-Andaman earthquake are relatively small, indicating these three earthquakes have no significant contribution to the long-term tectonic motion of Malaysia. Overall, this paper aims to provide a general insight into the tectonic motion of Malaysia which, expectedly, may benefit other scientific fields.

  14. Upright folding during extensional and transtensional tectonics

    NASA Astrophysics Data System (ADS)

    Teyssier, Christian; Fossen, Haakon; Rey, Patrice F.; Whitney, Donna L.

    2017-04-01

    Upright folds are common structures that develop in response to horizontal shortening in layered material, for example in foreland basins that surround orogens. While the contractional nature of these folds is not in doubt, interpretation of their tectonic setting needs careful consideration. Here we focus on two examples: (1) folds developed in transtension; and (2) folds developed during the flow of deep crust in response to lithospheric extension. In both cases we consider folding of nearly horizontal layers that are either primary (bedding) or secondary (foliation). Strain theory inspired by John Ramsay's work makes predictions for the behavior of material lines and planes as well as strain axes (instantaneous, finite) during transtensional deformation. Results show: folds can form in transtension; fold hinges rotate toward the direction of divergence (and not the shear zone boundary as they do in transpression), providing unique insight into ancient plate motions; fold tightness is controlled by the obliquity of divergence and not finite strain; hinge parallel stretching is always greater than hinge-perpendicular shortening, resulting in constriction strain and boudinage of fold hinges. Taken together these results provide a rigorous framework for interpreting field observations where structures are complex and boundary conditions unclear. These principles are applied to various tectonic settings ranging from active tectonic regions of oblique divergence in western North America to ancient folding that developed during oblique extension of the Western Gneiss Region, deposition of Devonian basins, and exhumation of ultrahigh-pressure rocks in the Norwegian Caledonides. The other class of upright folds that form during extension may require revision of the tectonic interpretation of structural overprints in orogenic cores, for example in gneiss/migmatite domes. Dynamic modeling of extension of thick/hot crust predicts a positive feedback between extension of

  15. [Formation of medical education in North Korea: 1945-1948].

    PubMed

    Heo, Yun-Jung; Cho, Young-Soo

    2014-08-01

    This study focuses on the formation of medical education in North Korea from 1945 to 1948 in terms of the centralization of medical education, and on the process and significance of the systemization of medical education. Doctors of the past trained under the Japanese colonial system lived and worked as liberalists. More than half of these doctors who were in North Korea defected to South Korea after the country was liberated. Thus the North Korean regime faced the urgent task of cultivating new doctors who would 'serve the state and people.' Since the autumn of 1945, right after national liberation, Local People's Committees organized and implemented medical education autonomously. Following the establishment of the Provisional People's Committee of North Korea, democratic reform was launched, leading to the centralized administration of education. Consequently, medical educational institutions were realigned, with some elevated to medical colleges and others shut down. The North Korean state criticised the liberalistic attitude of doctors and the bureaucratic style of health administration, and tried to reform their political consciousness through political inculcation programs. The state also grant doctors living and housing privileges, which show its endeavor to build 'state medicine'. By 1947, a medical education system was established in which the education administration was put in charge of training new doctors while the health administration was put in charge of nurturing and retraining health workers. In this way, the state was the principal agent that actively established a centralized administrative system in the process of the formation of medical education in North Korea following national liberation. Another agent was deeply involved in this process - the faculty that was directly in charge of educating the new doctors. Studying the medical faculty remains another research task for the future. By exploring how the knowledge, generational experience

  16. Tectonic ancestry of central Montana and its influence on inversion tectonics

    SciTech Connect

    Woodward, L.A.

    1996-06-01

    Inversion tectonics, where structurally low areas become structurally high, has profound implications for hydrocarbon exploration. Effective exploration depends on understanding structures, timing, and controls on tectonic inversion. In central Montana tectonic inversion occurred three times in Phanerozoic time and reflects Precambrian tectonic trends. Westerly striking, steep foliation in Archean crystalline rocks defines the tectonic grain in basement exposures. The Helena embayment of the Middle Proterozoic Belt Basin formed an east-trending aulacogen extending into the craton in central Montana. Westerly trending fault-blocks of probable Late Proterozoic age formed within the embayment. The trough was tectonically inverted in the Devonian, but was depressed in the Carboniferous, accumulating major thicknesses of Madison Group and Big Snowy Group strata. Tectonic inversion again occurred with rise of the {open_quotes}Belt island{close_quotes} in the Jurassic. The trough was reactivated with a thick accumulation of lower Lower Cretaceous strata. Laramide (Late Cretaceous-early Tertiary) deformation resulted in tectonic inversion with rise of the Little Belt, Big Snowy, and related uplifts. Reactivation with reverse and strike-slip movement occurred on synsedimentary Proterozoic westerly trending normal faults that bounded the Helena embayment. Subsidence was probably related to crustal extension, whereas tectonic inversion and rise is inferred to be caused by crustal shortening. West-northwesterly trending en echelon folds that cross central Montana suggest major left shift. The Precambrian structural framework and fabric of the region thus appear to have had major influence on tectonic features that were multiply reactivated in Phanerozoic time.

  17. "Copy and Fix": A New Technique of Harvesting Freehand and Horseshoe Tectonic Grafts.

    PubMed

    Samarawickrama, Chameen; Goh, Rachel; Vajpayee, Rasik B

    2015-11-01

    To describe a new technique for harvesting freehand and horseshoe tectonic corneal grafts. A retrospective, noncomparative interventional case series of 3 eyes from 2 patients was included. The area to be excised from the host was marked with a marking pen. Using the principle of the light table from architecture, the donor corneoscleral rim was placed over the marked area with an ophthalmic viscoelastic device in the interface to provide a coupling medium. The donor was then marked, tracing the exact shape of the tectonic graft with a 0.2-mm overlap ("copy"). This was harvested after mounting on an artificial anterior chamber and sutured in place with 10-0 nylon ("fix") to provide an exact copy of the eccentric or horseshoe shape of the tectonic graft. One eye had a full-thickness freehand tectonic corneal graft for perforated microbial keratitis too large to glue. Two eyes from the same patient had anterior lamellar horseshoe tectonic grafts for Terrien marginal degeneration. None of the grafts required any modification in their dimensions after harvesting. All grafts were easy to perform and tectonically stable postoperatively. A significant visual improvement was observed in all cases. The "copy and fix" technique is a simple and effective new technique that consistently and accurately maps and harvests freehand and horseshoe tectonic corneal grafts.

  18. Tertiary rifting and its related structural development of the southern offshore Korea

    NASA Astrophysics Data System (ADS)

    Sunwoo, Don

    2017-04-01

    Analysis of regional multi-channel seismic data integrated with exploratory wells has helped to investigate the structural and stratigraphic evolution of the southern offshore Korea. The northeast-southwest trending Taiwan Sinzi Fold Belt separates the area into two regions, the northern East China Sea Shelf Basin and the northern Okinawa Trough, with different structural features. The northern East China Sea Shelf Basin is characterized by Hupijiao Rise and Oligocene and late Miocene folded structures, whereas no uplifted and folded structures exist in the northern Okinawa Trough. However, the basement structure in both regions is much similar. The structure is characterized by a series of half-grabens and tilted fault blocks bounded by listric faults associated with rifting activity. These structures are more distinct in the northern Okinawa Trough. Rifting and extension in the northern East China Sea Shelf Basin, probably initiated in the Paleogene, resulted in a series of grabens and half-grabens. In the late Oligocene, the area west of the Hupijiao Rise experienced compressional tectonism and subsequent erosion flattened the area. In the early Miocene, extension and rifting resumed and the Hupijiao Rise uplifted locally. A second phase of compression, probably triggered by changes in plate motions caused large-scale uplift and folding in the eastern part of the area during the late Miocene. Subsequent erosion leveled the area including the Taiwan Sinzi Fold Belt, resulting in a significant regional unconformity. In contrast, the rifting and extension in the northern Okinawa Trough probably began in late Miocene and continued until early Pleistocene. The most active rifting occurred during early Pliocene and the rifting seems to become weaker during late Pliocene and early Pleistocene. The late Miocene unconformity that eroded the Taiwan Sinzi Fold Belt forms a conformable surface in the northern Okinawa Trough

  19. Tectonic and neotectonic framework of the Yucca Mountain Region

    SciTech Connect

    Schweickert, R.A.

    1992-09-30

    Highlights of major research accomplishments concerned with the tectonics and neotectonics of the Yucca Mountain Region include: structural studies in Grapevine Mountains, Bullfrog Hills, and Bare Mountain; recognition of significance of pre-Middle Miocene normal and strike-slip faulting at Bare Mountain; compilation of map of quaternary faulting in Southern Amargosa Valley; and preliminary paleomagnetic analysis of Paleozoic and Cenozoic units at Bare Mountain.

  20. Venus: Mantle convection, hotspots, and tectonics

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1989-01-01

    The putative paradigm that planets of the same size and mass have the same tectonic style led to the adaptation of the mechanisms of terrestrial plate tectonics as the a priori model of the way Venus should behave. Data acquired over the last decade by Pioneer Venus, Venera, and ground-based radar have modified this view sharply and have illuminated the lack of detailed understanding of the plate tectonic mechanism. For reference, terrestrial mechanisms are briefly reviewed. Venusian lithospheric divergence, hotspot model, and horizontal deformation theories are proposed and examined.

  1. Interdisciplinary Studies of Magma-Tectonic Interactions

    NASA Astrophysics Data System (ADS)

    LaFemina, Peter; Stix, John; Saballos, Armando

    2013-08-01

    The Pan-American Advanced Studies Institute (PASI) Magma-Tectonic Interactions in the Americas brought together researchers, postdoctoral fellows, and graduate students from every country in the Americas with active volcanoes and one participant from Iceland. Lecturers presented the latest geochemical and geophysical approaches to studying magma-tectonic interactions. Participants were introduced to the tectonics and volcanism of Nicaragua through a daylong field trip and given opportunities to collect and analyze their own data, including seismic, geodetic, and geochemical data, at the Cerro Negro volcano.

  2. Galapagos Tectonics and Evolution (Invited)

    NASA Astrophysics Data System (ADS)

    Hey, R. N.

    2010-12-01

    Galapagos is now considered one of the type-examples of hotspot-ridge interaction, although in the early years of plate tectonics it was generally thought that this interpretation was demonstrably wrong, with two influential groups insisting that non-hotspot models were required for this area. The key to understanding Galapagos tectonic evolution was the recognition that small ridge axis jumps toward the hotspot had occurred, producing complicated magnetic anomalies and asymmetric lithospheric accretion. My dissertation work, guided by Jason Morgan, showed that this simple modification to plate tectonic theory could resolve the seemingly compelling geometric arguments against the Cocos and Carnegie aseismic ridges being Galapagos hotspot tracks, and further that if Galapagos were a hotspot near Fernandina, fixed with respect to the Hawaii hotspot, there should be aseismic ridges on the Cocos and Nazca plates with the observed Cocos and Carnegie ridge geometry, both aseismic ridges forming when the hotspot was ridge-centered, but only the Carnegie ridge since the plate boundary migrated north of the hotspot. A great deal of subsequent research has shown that some areas are considerably more complicated than originally thought, but the following basic model still appears to hold. The Farallon plate split apart along the Grijalva scarp, possibly a preexisting Pacific-Farallon FZ that intersected the hotspot at this time (although alternative interpretations exist), probably in response to tensional stress caused by slab pull in different directions at the Mid-America and Peru-Chile trenches. This break-up allowed more orthogonal subduction of independent Cocos and Nazca plates beginning shortly after 25 Ma. The original Cocos-Nazca ridge trended E-NE, but soon reorganized into N-S spreading segments. The subsequent evolution involved substantial northward ridge migration and ridge jumps, mostly toward the Galapagos hotspot. Recent ridge jumps have occurred in

  3. Divorce in Korea: Trends and Educational Differentials

    ERIC Educational Resources Information Center

    Park, Hyunjoon; Raymo, James M.

    2013-01-01

    The authors extend comparative research on educational differences in divorce by analyzing data from Korea. A primary motivation was to assess whether the theoretically unexpected negative educational gradient in divorce in Japan is also observed in Korea. Using vital statistics records for marriages and divorces registered between 1991 and 2006,…

  4. Divorce in Korea: Trends and Educational Differentials

    ERIC Educational Resources Information Center

    Park, Hyunjoon; Raymo, James M.

    2013-01-01

    The authors extend comparative research on educational differences in divorce by analyzing data from Korea. A primary motivation was to assess whether the theoretically unexpected negative educational gradient in divorce in Japan is also observed in Korea. Using vital statistics records for marriages and divorces registered between 1991 and 2006,…

  5. How much plutonium does North Korea have?

    SciTech Connect

    Albright, D.

    1994-09-01

    U.S. intelligence discovered in the 1980s that North Korea was building a small nuclear reactor. The reactor was described as a gas-cooled, graphite-moderated model similar to those Britian and France used to produce electric power as well as plutonium for nuclear weapons. When Western nations expressed concern about the reactor Russia pressed North Korea to sign the Non-Proliferation Treaty (NPT) which it did on December 12, 1985. However, North Korea stalled on signing the required safeguards agreement that allows the International Atomic Energy Agency (IAEA) to inspect nuclear facilities until January 1992. Inspections by the IAEA revealed discrepancies with the amounts of plutonium separated as declared by the North Koreans. The IAEA also received reports that two North Korean waste sites were hidden. By February 1993 the IAEA and the North Koreans has reached an impasse: North Koreas initial declarations of plutonium inventory could not be confirmed and North Korea refused to cooperate. At the least, North Korea admits to having separated 100 grams of plutonium. At the most, worst case estimate, they could have a total of 6 - 13 kilograms of separated plutonium. A first nuclear weapon can require up to 10 kilograms of weapon-grade plutonium. Any settlement needs to include a way to insure that the IAEA can verify North Korea`s past nuclear activities and determine the amount of plutonium that may have been separated in the past. 2 refs.

  6. Teaching about Korea in Secondary School.

    ERIC Educational Resources Information Center

    Van Decar, Patricia

    1988-01-01

    Presents 12 study guides for teaching secondary school students about Korean history and culture. The study guides deal with ancient legends, history, family, women's roles, traditions, folk customs, economic development, the division of Korea, the Korean War, links with the United States, and comparisons between North and South Korea. (GEA)

  7. South Korea Powers Ahead with Globalization Plans

    ERIC Educational Resources Information Center

    McNeill, David

    2009-01-01

    For government officials in South Korea, it's a vision worth savoring: Within the next decade, South Korea becomes Southeast Asia's top higher-education destination, poaching thousands of Chinese, Indian, and Japanese students from American universities and overtaking rivals Singapore, Malaysia, and Hong Kong. The higher-education system's…

  8. South Korea Powers Ahead with Globalization Plans

    ERIC Educational Resources Information Center

    McNeill, David

    2009-01-01

    For government officials in South Korea, it's a vision worth savoring: Within the next decade, South Korea becomes Southeast Asia's top higher-education destination, poaching thousands of Chinese, Indian, and Japanese students from American universities and overtaking rivals Singapore, Malaysia, and Hong Kong. The higher-education system's…

  9. International University Will Open in North Korea

    ERIC Educational Resources Information Center

    McNeill, David

    2007-01-01

    This article reports that construction is nearing completion on Pyongyang University of Science and Technology in North Korea, in which academics from around the world will teach the best of the country's graduate students. This will be North Korea's first international university and will let the world know that the capacity of their scientists…

  10. International University Will Open in North Korea

    ERIC Educational Resources Information Center

    McNeill, David

    2007-01-01

    This article reports that construction is nearing completion on Pyongyang University of Science and Technology in North Korea, in which academics from around the world will teach the best of the country's graduate students. This will be North Korea's first international university and will let the world know that the capacity of their scientists…

  11. Exogenous model of global tectonics

    NASA Astrophysics Data System (ADS)

    Kalenda, Pavel; Wandrol, Ivo; Kopf, Tomáš; Frydrýšek, Karel; Neumann, Libor; Procházka, Václav; Ostřihanský, Lubor

    2014-05-01

    of the Science as a whole. References Berger, J. (1975): A Note on Thermoelastic Strains and Tilts, 1975, J. Geophys.Res., 80, pp. 274-277. Croll, J.G.A. (2006): From asphalt to the Arctic: new insights into thermo-mechanical ratcheting processes. III Int. Conf. On Computational Mechanics. Lisbon, Portugal, 5-8 June. Croll, J.G.A. (2007): A new hypothesis for Earth lithosphere evolution. New Concepts in Global Tectonics Newsletter, no. 45, December, 2007, 34-51. IPCC (2007): IPCC Fourth Assessment Report: Climate Change 2007 (AR4). http://www.ipcc.ch/publications_and_data/publications_and_data_reports.shtml Kalenda P. et al. (2012): Tilts, global tectonics and earthquake prediction. SWB, London, 247pp.

  12. Tectonic Subsidence Analysis of the Pearl River Mouth Basin, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Tang, X.; Huang, S. S. X. E. C.; Zhuang, W.; LIU, Z.; Duan, W.; Hu, S.

    2015-12-01

    The Pearl River Mouth Basin (PRMB hereafter) in the northern margin of the South China Sea has attracted great attention not only because of its special tectonic location but also for its abundant hydrocarbon resources. Tectonic evolution controls the petroleum geological condition of hydrocarbon-bearing basins. Efforts have been made to understand the tectonic evolution of this basin. However, many issues about the tectonic features and the evolution process of this basin, such as the age of the breakup unconformities and the anomalously accelerated subsidence during the post-rifting stage, remain controversial. Here we employ tectonic subsidence analysis of sedimentary basins, a technique of removing isostatic loading and compaction effects by back-stripping, to investigate the tectonic controls on the basin formation of the PRMB. We performed the analysis on 4 drill wells and 43 synthetic wells constructed based on recently acquired seismic profiles. The result shows that tectonic subsidence in the eastern sags of the PRMB began to decrease at ~30Ma while in the western sags the onset was ~23.8Ma. This suggests that the break-up time i.e. the end of rifting in the PRMB is earlier in the eastern sags than in the western sags. Abnormally accelerated tectonic subsidence occurred between 17.5-16.4Ma during the post-rifting stage, at an average subsidence rate as high as 301.9m/Ma. This phenomenon discriminates the PRMB from the category of classical Atlantic passive continental marginal basins, of which the tectonic subsidence during the post-rifting stage decays exponentially. The main objective of this paper is to provide insights into the geological and geodynamic evolution of the PRMB. The result bears significance to hydrocarbon exploration in this region.

  13. Geomorphic Indices in the Assessment of Tectonic Activity in Forearc of the Active Mexican Subduction Zone

    NASA Astrophysics Data System (ADS)

    Gaidzik, K.; Ramirez-Herrera, M. T.

    2015-12-01

    Rapid development of GIS techniques and constant advancement of digital elevation models significantly improved the accuracy of extraction of information on active tectonics from landscape features. Numerous attempts were made to quantitatively evaluate recent tectonic activity using GIS and DEMs, and a set of geomorphic indices (GI), however these studies focused mainly on sub-basins or small-scale areal units. In forearc regions where crustal deformation is usually large-scale and do not concentrate only along one specific fault, an assessment of the complete basin is more accurate. We present here the first attempt to implement thirteen GI in the assessment of active tectonics of a forearc region of an active convergent margin using the entire river basins. The GIs were divided into groups: BTAI - basin geomorphic indices (reflecting areal erosion vs. tectonics) and STAI - stream geomorphic indices (reflecting vertical erosion vs. tectonics). We calculated selected indices for 9 large (> 450 km2) drainage basins. Then we categorized the obtained results of each index into three classes of relative tectonic activity: 1 - high, 2 - moderate, and 3 - low. Finally we averaged these classes for each basin to determine the tectonic activity level (TAI). The analysis for the case study area, the Guerrero sector at the Mexican subduction zone, revealed high tectonic activity in this area, particularly in its central and, to a lesser degree, eastern part. This pattern agrees with and is supported by interpretation of satellite images and DEM, and field observations. The results proved that the proposed approach indeed allows identification and recognition of areas witnessing recent tectonic deformation. Moreover, our results indicated that, even though no large earthquake has been recorded in this sector for more than 100 years, the area is highly active and may represent a seismic hazard for the region.

  14. Tectonics and Volcanism of East Africa as Seen Using Remote Sensing Imagery

    NASA Technical Reports Server (NTRS)

    Hutt, Duncan John

    1996-01-01

    The East African Rift is the largest area of active continental geology. The tectonics of this area has been studied with remote sensing data, including AVHRR, Landsat MSS and TM, SPOT, and electronic still camera from Shuttle. Lineation trends have been compared to centers of volcanic and earthquake activity as well as the trends shown on existing geologic maps. Remote sensing data can be used effectively to reveal and analyze significant tectonic features in this area.

  15. Aging Risk and Health Care Expenditure in Korea

    PubMed Central

    Tchoe, Byongho; Nam, Sang-Ho

    2010-01-01

    This paper analyzes the impact of population aging on health care expenditures in Korea. Examination of the age-expenditure profile reveals that health care resources are allocated more for the older cohort of population over time, suggesting significant growth of health care expenditures due to population aging. We contend, however, that population aging is considered as a parameter rather than an independent variable to explain rising health care expenditures. This paper shows that population aging is not found to be a significant determinant of health care expenditures according to the econometric analysis using OECD health data and time-series data for Korea. Using the components decomposition method, which measures the contribution of each component of health care expenditure, we estimate that population aging contributes only less than 10 percent. PMID:20948958

  16. Planning for a Peaceful Korea

    DTIC Science & Technology

    2001-03-01

    military service schools , • highlight the range of damage that U.S. and South Korean forces could inflict in a variety of counterstrikes against a North...majority of the North’s so-called 29 “technocrats” have not been educated at places like MIT, the Ivy League, Stanford, or the London School of...recollections that somehow on the flight home from World War II, Korea got caught in a badminton game between the United States and the USSR, and ended up

  17. North Korea: Terrorism List Removal

    DTIC Science & Technology

    2008-11-06

    ct/rls/crt/2006/82736.htm] at p. 147. 28 Yi Sang-il and Chin Se-ku. Yongbyon nuclear facility can be disabled within a year. JongAng Ilbo (internet...Interview of the President by Foreign Print Media, August 30, 3007. 32 Choe Sang- hun and David E. Sanger, North Korea claims U.S. will remove sanctions...smuggle conventional arms, including machine guns , automatic rifles, and anti-tank rocket launchers, to the Tamil Tigers in Sri Lanka. The Sri Lankan

  18. The interior of Venus and Tectonic implications

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.; Malin, M. C.

    1983-01-01

    It is noted in the present consideration of the Venus lithosphere and its implications for plate tectonics that the major linear elevated regions of Venus, which are associated with Beta Regio and Aphrodite Terra, do not seem to have the shape required for sure interpretation as the divergent plate boundaries of seafloor spreading. Such tectonics instead appear to be confined to the median plains, and may not be resolvable in the Pioneer Venus altimetry data. The ratios of gravity anomalies to topographic heights indicate that surface load compensation occurs at depths greater than about 100 km under the western Aphrodite Terra and 400 km under Beta Regio, with at least some of this compensation probably being maintained by mantle convection. It is also found that the shape of Venus's hypsogram is very different from the ocean mode of the earth's hypsogram, and it is proposed that Venus tectonics resemble intraplate, basin-and-swell tectonics on earth.

  19. The interior of Venus and Tectonic implications

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.; Malin, M. C.

    1983-01-01

    It is noted in the present consideration of the Venus lithosphere and its implications for plate tectonics that the major linear elevated regions of Venus, which are associated with Beta Regio and Aphrodite Terra, do not seem to have the shape required for sure interpretation as the divergent plate boundaries of seafloor spreading. Such tectonics instead appear to be confined to the median plains, and may not be resolvable in the Pioneer Venus altimetry data. The ratios of gravity anomalies to topographic heights indicate that surface load compensation occurs at depths greater than about 100 km under the western Aphrodite Terra and 400 km under Beta Regio, with at least some of this compensation probably being maintained by mantle convection. It is also found that the shape of Venus's hypsogram is very different from the ocean mode of the earth's hypsogram, and it is proposed that Venus tectonics resemble intraplate, basin-and-swell tectonics on earth.

  20. Fissure near Cerberus Fossae with Tectonic Morphologies

    NASA Image and Video Library

    2014-01-15

    The linearity of the volcanic vent shown in this image observed by NASA Mars Reconnaissance Orbiter, in conjunction with evidence of lava flow from the vent, suggests control by combined volcano-tectonic processes.

  1. Oligocene tectonics and sedimentation, California

    USGS Publications Warehouse

    Nilsen, T.H.

    1984-01-01

    During the Oligocene epoch, California was marked by extensive nonmarine sedimentation, in contrast to its pre-Oligocene and post-Oligocene depositional history. The Oligocene continental deposits are especially widespread in southern California and fill a number of small and generally partly restricted basins. Fluvial facies in many basins prograded over previously deposited lower Tertiary turbidites. Volcanism, from widespread centers, was associated with the nonmarine sedimentation. However, some basins remained marine and a few contain Oligocene turbidites and pelagic sediments deposited at bathyal depths. The Oligocene redbeds of California do not form a post-orogenic molasse sequence comparable to the Old Red Sandstone or Alpine molasse. They are synorogenic and record local uplift of basins and surrounding source areas. Late Cretaceous to contemporary orogenesis in California has been generally characterized by the formation of small restricted basins of variable depth adjacent to small upland areas in response to strike-slip faulting. Deposition of Oligocene redbeds was associated with climatic change from warm and humid to cold and semiarid, and a global lowering of sea level. Oligocene tectonism occurred during the transition from subduction of the Farallon Plate to initiation of the modern San Andreas transform system. However, the major influence that caused uplift, formation of fault-bounded basins, and extensive redbed deposition, especially in southern California, was the approach of the Pacific-Farallon spreading ridge to the western margin of California. ?? 1984.

  2. Volcanological constraints of Archaean tectonics

    NASA Technical Reports Server (NTRS)

    Thurston, P. C.; Ayres, L. D.

    1986-01-01

    Volcanological and trace element geochemical data can be integrated to place some constraints upon the size, character and evolutionary history of Archean volcanic plumbing, and hence indirectly, Archean tectonics. The earliest volcanism in any greenhouse belt is almost universally tholeitic basalt. Archean mafic magma chambers were usually the site of low pressure fractionation of olivine, plagioclase and later Cpx + or - an oxide phase during evolution of tholeitic liquids. Several models suggest basalt becoming more contaminated by sial with time. Data in the Uchi Subprovince shows early felsic volcanics to have fractionated REE patterns followed by flat REE pattern rhyolites. This is interpreted as initial felsic liquids produced by melting of a garnetiferous mafic source followed by large scale melting of LIL-rich sial. Rare andesites in the Uchi Subprovince are produced by basalt fractionation, direct mantle melts and mixing of basaltic and tonalitic liquids. Composite dikes in the Abitibi Subprovince have a basaltic edge with a chill margin, a rhyolitic interior with no basalt-rhyolite chill margin and partially melted sialic inclusions. Ignimbrites in the Uchi and Abitibi Subprovinces have mafic pumice toward the top. Integration of these data suggest initial mantle-derived basaltic liquids pond in a sialic crust, fractionate and melt sial. The inirial melts low in heavy REE are melts of mafic material, subsequently melting of adjacent sial produces a chamber with a felsic upper part underlain by mafic magma.

  3. The jubilee of plate tectonics

    NASA Astrophysics Data System (ADS)

    Glen, William; Frankel, Henry

    What should one expect at a birthday gathering for an idea that suffered disdain from birth, but was later transformed overnight into the ruling global theory of the Earth sciences? Tom Hilde and Richard Carlson (Texas A&M University, College Station, Tex.), under the auspices of the Texas A&M Geodynamics Research Institute, with the cooperation of the National Aeronautics and Space Administration (NASA) , the Inter-Union Commission on the Lithosphere, and the U.S. Geodynamics Committee, convened an unprecedented gathering of the makers of Earth science's modern revolution and a large number of their foremost disciples at Texas A&M April 22- 24 , 1987.Those who missed the show will have to read for weeks to learn of the panoply of profound new developments across the broad front of research bearing on plate tectonics, but those with an interest in their own intellectual genealogy will not be able to recapture the sense of historic moment that pervaded Rudder Tower Conference Center as many of the old revolutionaries opened windows on the past. Of the 20 key participants or originators who were invited to speak, all but four sent abstracts. Pleased and surprised by this strong response, the convenors found themselves in the rather difficult position of having to limit the number of talks by nonoriginators to 20. The unique assembly also provided the first opportunity to video interviews with more than a dozen of the originators.

  4. Mapping Tectonic Stress Using Earthquakes

    SciTech Connect

    Arnold, Richard; Townend, John; Vignaux, Tony

    2005-11-23

    An earthquakes occurs when the forces acting on a fault overcome its intrinsic strength and cause it to slip abruptly. Understanding more specifically why earthquakes occur at particular locations and times is complicated because in many cases we do not know what these forces actually are, or indeed what processes ultimately trigger slip. The goal of this study is to develop, test, and implement a Bayesian method of reliably determining tectonic stresses using the most abundant stress gauges available - earthquakes themselves.Existing algorithms produce reasonable estimates of the principal stress directions, but yield unreliable error bounds as a consequence of the generally weak constraint on stress imposed by any single earthquake, observational errors, and an unavoidable ambiguity between the fault normal and the slip vector.A statistical treatment of the problem can take into account observational errors, combine data from multiple earthquakes in a consistent manner, and provide realistic error bounds on the estimated principal stress directions.We have developed a realistic physical framework for modelling multiple earthquakes and show how the strong physical and geometrical constraints present in this problem allow inference to be made about the orientation of the principal axes of stress in the earth's crust.

  5. Tectonic blocks and molecular clocks

    PubMed Central

    2016-01-01

    Evolutionary timescales have mainly used fossils for calibrating molecular clocks, though fossils only really provide minimum clade age constraints. In their place, phylogenetic trees can be calibrated by precisely dated geological events that have shaped biogeography. However, tectonic episodes are protracted, their role in vicariance is rarely justified, the biogeography of living clades and their antecedents may differ, and the impact of such events is contingent on ecology. Biogeographic calibrations are no panacea for the shortcomings of fossil calibrations, but their associated uncertainties can be accommodated. We provide examples of how biogeographic calibrations based on geological data can be established for the fragmentation of the Pangaean supercontinent: (i) for the uplift of the Isthmus of Panama, (ii) the separation of New Zealand from Gondwana, and (iii) for the opening of the Atlantic Ocean. Biogeographic and fossil calibrations are complementary, not competing, approaches to constraining molecular clock analyses, providing alternative constraints on the age of clades that are vital to avoiding circularity in investigating the role of biogeographic mechanisms in shaping modern biodiversity. This article is part of the themed issue ‘Dating species divergences using rocks and clocks’. PMID:27325840

  6. Tectonic blocks and molecular clocks.

    PubMed

    De Baets, Kenneth; Antonelli, Alexandre; Donoghue, Philip C J

    2016-07-19

    Evolutionary timescales have mainly used fossils for calibrating molecular clocks, though fossils only really provide minimum clade age constraints. In their place, phylogenetic trees can be calibrated by precisely dated geological events that have shaped biogeography. However, tectonic episodes are protracted, their role in vicariance is rarely justified, the biogeography of living clades and their antecedents may differ, and the impact of such events is contingent on ecology. Biogeographic calibrations are no panacea for the shortcomings of fossil calibrations, but their associated uncertainties can be accommodated. We provide examples of how biogeographic calibrations based on geological data can be established for the fragmentation of the Pangaean supercontinent: (i) for the uplift of the Isthmus of Panama, (ii) the separation of New Zealand from Gondwana, and (iii) for the opening of the Atlantic Ocean. Biogeographic and fossil calibrations are complementary, not competing, approaches to constraining molecular clock analyses, providing alternative constraints on the age of clades that are vital to avoiding circularity in investigating the role of biogeographic mechanisms in shaping modern biodiversity.This article is part of the themed issue 'Dating species divergences using rocks and clocks'. © 2016 The Authors.

  7. Geoacoustic Model of the Strait of Korea

    DTIC Science & Technology

    1991-10-01

    is rough due, in a large part, to the extensional tectonism associated with the back-arc-basin environment of the nearby Sea of Japan. Acoustic...is rough due, in a large part, to the extensional tectonism associated with the back-arc-basin environment of the nearby Sea of Japan. Acoustic...basement rock of complex tectonic history (Fig 7). The basement under the western channel of the strait is probably part of the Fukien-Reinan massif

  8. Gender Equity: Womens Political Empowerment In South Korea

    DTIC Science & Technology

    2015-03-01

    25  Table 6.  Economically Active Population by Sex ...South Korea. B. SIGNIFICANCE OF THE RESEARCH QUESTION According to South Korea’s 2013 government data, a more naturally expected sex ratio at birth...Male Superiority, and Korean Women in Politics: Changing Gender Relations in a “patriarchal Democracy.”“ Sex Roles 28, no. 1–2 (1993): 74. 48

  9. Genetic structure of Lycorma delicatula (Hemiptera: Fulgoridae) populations in Korea: implication for invasion processes in heterogeneous landscapes.

    PubMed

    Park, Marana; Kim, Kyung-Seok; Lee, Joon-Ho

    2013-08-01

    Lycorma delicatula (White) was identified in 2004 as an invasive pest in South Korea, where it causes serious damage to vineyard crops. To investigate the population structure and dispersal pattern of L. delicatula in South Korea, we estimated the population genetic structure and gene flow among nine locations across the country using seven microsatellite markers. Although L. delicatula spread throughout most of its geographical range in South Korea within 5-7 years following invasion, its populations show evidence of genetic structuring across the range with a low but significant global F ST (genetic differentiation across all populations) of 0.0474. Bayesian-based clustering analysis indicates the presence of at least three genetically unique populations in South Korea, including populations in northeastern South Korea, which show a distinct genetic background. However, isolation by distance suggests that populations in South Korea have not yet reached genetic equilibrium. Estimates of the historical rate of gene flow (N e m) indicate that relatively high rates of flow have been maintained among populations within the western region, which may indicate recent range expansion. A population assignment test using the first-generation migrant detection method suggested that long-distance dispersal of L. delicatula may have occurred over large areas of South Korea. More complex dispersal patterns may have occurred during L. delicatula invasion of heterogeneous landscapes in South Korea.

  10. Tectonic and metallogenic model for northeast Asia

    USGS Publications Warehouse

    Parfenov, Leonid M.; Nokleberg, Warren J.; Berzin, Nikolai A.; Badarch, Gombosuren; Dril, Sergy I.; Gerel, Ochir; Goryachev, Nikolai A.; Khanchuk, Alexander I.; Kuz'min, Mikhail I.; Prokopiev, Andrei V.; Ratkin, Vladimir V.; Rodionov, Sergey M.; Scotese, Christopher R.; Shpikerman, Vladimir I.; Timofeev, Vladimir F.; Tomurtogoo, Onongin; Yan, Hongquan; Nokleberg, Warren J.

    2011-01-01

    This document describes the digital files in this report that contains a tectonic and metallogenic model for Northeast Asia. The report also contains background materials. This tectonic and metallogenic model and other materials on this report are derived from (1) an extensive USGS Professional Paper, 1765, on the metallogenesis and tectonics of Northeast Asia that is available on the Internet at http://pubs.usgs.gov/pp/1765/; and (2) the Russian Far East parts of an extensive USGS Professional Paper, 1697, on the metallogenesis and tectonics of the Russian Far East, Alaska, and the Canadian Cordillera that is available on the Internet at http://pubs.usgs.gov/pp/pp1697/. The major purpose of the tectonic and metallogenic model is to provide, in movie format, a colorful summary of the complex geology, tectonics, and metallogenesis of the region. To accomplish this goal four steps were taken: (1) 13 time-stage diagrams, from the late Neoproterozoic (850 Ma) through the present (0 Ma), were adapted, generalized, and transformed into color static time-stage diagrams; (2) the 13 time-stage diagrams were placed in a computer morphing program to produce the model; (3) the model was examined and each diagram was successively adapted to preceding and subsequent diagrams to match the size and surface expression of major geologic units; and (4) the final version of the model was produced in successive iterations of steps 2 and 3. The tectonic and metallogenic model and associated materials in this report are derived from a project on the major mineral deposits, metallogenesis, and tectonics of the Northeast Asia and from a preceding project on the metallogenesis and tectonics of the Russian Far East, Alaska, and the Canadian Cordillera. Both projects provide critical information on bedrock geology and geophysics, tectonics, major metalliferous mineral resources, metallogenic patterns, and crustal origin and evolution of mineralizing systems for this region. The major

  11. Shanghanlun in Korea, 1610-1945

    PubMed Central

    Suh, Soyoung

    2015-01-01

    This article examines how Korean physicians of traditional medicine have utilized Zhang Ji’s 張 機 (150–219 CE) Shanghanlun 傷寒論 (Treatise on Cold Damage Disorders, just Treatise hereafter) from the 17th century to the early twentieth century. As one of the two most influential pillars of Chinese medicine, the Treatise, with its clinical implications, has inspired many scholars and practitioners in their pursuit of medical innovation. What, then, have been the Korean motivations in referring to the Treatise over the past few centuries? What does the Korean utilization and modification of the Chinese classic tell us about the desires, limits, and possibilities of pursuing medical innovations in Korea? By examining the ways in which major pre-modern Korean texts employed the Treatise, this article primarily aims to reveal patterns of (re)arranging the Treatise that formed an indigenous style of medicine. Under the growing sense of nationalist concern and colonial contestation in the early twentieth century, the Korean compilation of the Treatise began to depart from the earlier interpretations. A range of nationalist rhetoric and editorial designs reflect the Korean urgency in seeking resources to compete with Western medicine. The postcolonial consumption of the Treatise also reflects Korean strategies in navigating medical references from outside to meet their social and clinical agendas. The changing pattern of textual and professional utilization of the Treatise exemplifies how a significant Chinese text continues to be a living tradition in Korea by expanding the targeted audience and satisfying local demands. PMID:26778942

  12. Tectonic History of the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1993-01-01

    The topics covered include the following: patterns of deformation and volcanic flows associated with lithospheric loading by large volcanoes on Venus; aspects of modeling the tectonics of large volcanoes on the terrestrial planets; state of stress, faulting, and eruption characteristics of large volcanoes on Mars; origin and thermal evolution of Mars; geoid-to-topography ratios on Venus; a tectonic resurfacing model for Venus; the resurfacing controversy for Venus; and the deformation belts of Lavinia Planitia.

  13. Tectonic map of the Arabian Peninsula

    USGS Publications Warehouse

    Brown, Glen F.

    1972-01-01

    This tectonic map of the Arabian peninsula, prepared for the Audi Arabian Ministry of Petroleum and Mineral Resource, is the first of a series of peninsular maps that attempt to show regional features. Much recent information resulting from detailed geologic mapping notably within the Arabian craton, from geophysical surveys, both airborne and oceanographic in adjacent seas, from deep exploratory drilling, and from photography from the Gemini and Apollo space programs, has been used in the tectonic evaluation.

  14. Tectonic microplates: laying it down on wax

    NASA Astrophysics Data System (ADS)

    Katz, R. R.; Bodenschatz, E.

    2008-12-01

    We present a wax analogue model of sea-floor spreading that produces rotating, growing microplates. Wax microplates are kinematically similar to sea-floor tectonic microplates in terms of spreading rate and growth rate. Furthermore, their spiral pseudofault geometry is quantitatively consistent with Schouten's oceanic microplate model. These results suggest that Schouten's edge-driven microplate model captures the kinematics of tectonic microplate evolution on Earth. We propose a theory for the formation of microplates.

  15. Elysium Region, Mars: Characterization of tectonic features

    NASA Technical Reports Server (NTRS)

    Hall, J. L.; Solomon, S. C.; Head, J. W.; Mouginis-Mark, P. J.

    1984-01-01

    In this paper the tectonic features of the Elysium region are identified and characterized. Identification of features was made using USGS controlled photomosaics (Elysium quadrangle, and portions of Amenthes and Cebrenia quadrangles); Viking Orbiter photographic data were used in individual cases to assist in identification. The positions and orientations of tectonic features can then be used, in conjunction with estimates of the mass of the volcanic load obtained from gravity modelling, to constrain the thickness of the elastic lithosphere in the region.

  16. Tectonic grafts for corneal thinning and perforations.

    PubMed

    Vanathi, M; Sharma, Namrata; Titiyal, Jeewan S; Tandon, Radhika; Vajpayee, Rasik B

    2002-11-01

    To evaluate the success of tectonic grafts in cases of corneal thinning and perforations. We performed 42 tectonic grafts in 41 eyes of 40 patients. Three types of tectonic grafts were used in our treatment protocol. These were (a) full-thickness grafts, (b) mushroom grafts, and (c) lamellar grafts. The parameters evaluated were indications, visual acuity, location, size and type of graft, postoperative outcome, and complications, if any. The most common indication for tectonic grafts was corneal thinning and perforation subsequent to infection (12 eyes) followed by those due to immunologic causes (six eyes) and trauma (six eyes). Twenty-four full-thickness tectonic grafts, nine mushroom grafts, and nine lamellar patch grafts were performed. Anatomical success was achieved in 35 of 41 (85.4%) eyes. Visual acuity of 6/24 or better was obtained in 29 of 41 (70.73%) eyes. The mean of best-corrected visual acuity (expressed in decimal) improved from 0.2 +/- 0.26 to 0.34 +/- 0.26 at an average follow-up of 10.83 +/- 6.27 months. The major complications were peripheral anterior synechiae in four eyes (9.76%) and graft melting in five eyes (12.2%). Tectonic graft is a useful therapeutic option in selected cases of corneal thinning and perforations because it effectively restores the integrity of the eye and allows acceptable visual rehabilitation.

  17. Spreading continents kick-started plate tectonics.

    PubMed

    Rey, Patrice F; Coltice, Nicolas; Flament, Nicolas

    2014-09-18

    Stresses acting on cold, thick and negatively buoyant oceanic lithosphere are thought to be crucial to the initiation of subduction and the operation of plate tectonics, which characterizes the present-day geodynamics of the Earth. Because the Earth's interior was hotter in the Archaean eon, the oceanic crust may have been thicker, thereby making the oceanic lithosphere more buoyant than at present, and whether subduction and plate tectonics occurred during this time is ambiguous, both in the geological record and in geodynamic models. Here we show that because the oceanic crust was thick and buoyant, early continents may have produced intra-lithospheric gravitational stresses large enough to drive their gravitational spreading, to initiate subduction at their margins and to trigger episodes of subduction. Our model predicts the co-occurrence of deep to progressively shallower mafic volcanics and arc magmatism within continents in a self-consistent geodynamic framework, explaining the enigmatic multimodal volcanism and tectonic record of Archaean cratons. Moreover, our model predicts a petrological stratification and tectonic structure of the sub-continental lithospheric mantle, two predictions that are consistent with xenolith and seismic studies, respectively, and consistent with the existence of a mid-lithospheric seismic discontinuity. The slow gravitational collapse of early continents could have kick-started transient episodes of plate tectonics until, as the Earth's interior cooled and oceanic lithosphere became heavier, plate tectonics became self-sustaining.

  18. Preliminary analysis of Venusian tectonics and evolution

    NASA Astrophysics Data System (ADS)

    Nikishin, A. M.

    1990-11-01

    Five stages in the evolution of Venus are discussed: accretion, segregation of early crust from magma ocean; volcanic reworking of early crust, development of tectonics of soft plastic plates with formation of tesserae in compression zones and plains in dilatation zones; formation of weakened planetary zones of dilatation saturated by mantel hot-spot structures against a backdrop of dispersed mantel hot-spot tectonics and plateau volcanism. The following subjects are discussed: types of structures and structural regions of Venus; tectonic structure of Venus and its interpretation; thickness and composition of Venusian crust; model of geological evolution of Venus; asymmetry of tectonic structure of Venus; and reasons for the great differences in the tectonics of the Earth and Venus. The tectonics of Venus differ from those of the Earth because Venus was always impoverished in terms of water, a highly important agent of magmatism and the main fluid involved in the fusion fo sialic rocks. Venusian volcanism therefore was less intense and a sialic crust is largely absent. The greenhouse effect on Venus causes increased plasticity of its lithosphere.

  19. Ridge push engine of plate tectonics

    NASA Astrophysics Data System (ADS)

    Swedan, N. H.

    2015-07-01

    Convection of the upper mantle drives the tectonic plates. This convection is a thermodynamic cycle that exchanges heat and mechanical work between mantle and tectonic plates. Thermodynamics and observations indicate that the energy of the geological activities resulting from plate tectonics is equal to the latent heat of melting, calculated at mantle's pressure, of the new ocean crust regenerated at midocean ridges. This energy varies with the temperature of ocean floor, which is correlated with surface temperature. The main objective of this manuscript is to demonstrate that plate tectonics is a thermodynamic engine and can be calculated as such. Unlike existing tectonic models, the thermodynamic model is very sensitive to variations of the temperature of ocean floor, which is correlated with surface temperature. Therefore, the observed increase of geological activities can be projected with surface temperature rise. Other objectives of the manuscript are to calculate the force that drives the tectonic plates, estimate the energy released, and validate the calculations based on experiments and observations. In addition to the scientific merit of projecting the geological activities, a good projection can have a broader impact at the societal and economical levels. Investment and insurance related decisions are affected by climate change, and our ability to project the geological activities is of paramount importance for the economy and public safety. This work can thus provide tools to assess the risks and hazards associated with the trend of geological activities with surface temperature rise.

  20. Horizontal deformation in South Korea from permanent GPS network data, 2000-2003

    NASA Astrophysics Data System (ADS)

    Hamdy, A. M.; Park, P.-H.; Lim, H.-C.

    2005-02-01

    Analysis of continuous GPS data 2000-2003 at 50 stations of the Korean GPS Network (KGN) suggests that the southern part of the Korean peninsula is tectonically more stable than other regions in the Eastern Asia. The average velocity was ~1.5 mm/yr and the average overall strain rate was around -0.3 × 10-9str/yr. The obtained velocity field indicates the presence of anticlockwise rotation of the whole region with respect to Daejeon station (DAEJ), in the central part of South Korea. It also showed that KM-OB (Kyonggi Massif and the Okchon Basin) and YM-TB (Yeongnam Massif and Taebaeksan Basin) have left-lateral shearing movements. Both movements were confirmed by the deformation analysis of the KGN horizontal velocity field using the infinitesimal plate theory. The results show that South Korea moves toward the WNW direction with a velocity of 0.9 mm/yr with a slow anticlockwise rotation. The strain field in South Korea indicates the existence of both compression and tension. The compression and extension axes have WSW-EWE and NNW-SSE directions, respectively.

  1. Crustal Structure in Southern Korea From Joint Analysis of Teleseismic Receiver Functions and Surface Wave Dispersion

    NASA Astrophysics Data System (ADS)

    Chang, S.; Baag, C.

    2004-12-01

    We estimated crustal structures at eighteen broadband stations in southern Korea by combining receiver functions and surface wave dispersion with the genetic algorithm (GA). The trend of the Moho depths estimated from the GA inversion generally coincides with the topography of the surface, ranging from 26 km to 36 km in inland. However, the Moho depth distribution does not agree with the topography in the region around the Chugaryeong Fault located approximately in NNE-SSW direction in the central area of the Korean peninsula. The shallow Moho depth under this region may be related to magmatic rift and consequential crustal thinning processes along the fault caused by an extensional tectonic movement. Another discrepancy is found in the Gyeongsang Basin, which was formed by the sedimentary deposits accumulated during Cretaceous extension caused by retroarc environment. The thick crust may be caused by both the maturity of basin and underplating of magma materials after the closure of the basin. The average crustal velocity is variable from 6.02 km/sec to 6.51 km/sec over southern Korea. This indicates that crustal structures in southern Korea involve diverse velocity profiles, changing rapidly with distance. It is also a remarkable phenomenon that an obvious discontinuity of the velocity is observed at 8-10 km depths under several stations.

  2. 78 FR 32356 - United States-Korea Free Trade Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-30

    ... 178 RIN 1515-AD86 United States-Korea Free Trade Agreement AGENCIES: U.S. Customs and Border... United States-Korea Free Trade Agreement entered into by the United States and the Republic of Korea.... SUPPLEMENTARY INFORMATION: Background On June 30, 2007, the United States and the Republic of Korea...

  3. Exploring links between tectonics, catchment morphology and hydrographs across Europe

    NASA Astrophysics Data System (ADS)

    Vanmaercke, Matthias; Campforts, Benjamin; Van Ruyskensvelde, Glenn; Poesen, Jean

    2016-04-01

    A growing number of studies show that contemporary catchment sediment yields (SY, [t/km²/y]) are strongly correlated to patterns of seismic activity at regional to continental scales. Nonetheless, the mechanisms explaining these correlations are still poorly understood. Seismicity may increase SY by triggering landslides or weakening the surface lithology. On the other hand seismicity can be considered as a proxy for tectonic movements, while there is a growing consensus that tectonics exert an important influence on catchment morphology. This morphology influences the properties of runoff events (e.g. peak discharge, stream power). Given the large influence of large runoff events on annual SY, it is therefore possible that observed correlations between SY and seismicity are (at least partly) attributable to tectonic influences on catchment morphology. We test this hypothesis by investigating links between runoff hydrographs and patterns in catchment properties at a European scale using numerous catchment indices such as the slope, channel steepness, circularity, drainage length, river network topology, etc. From DEMs with a resolution of ca. 100m we randomly delineated over 5000 catchments across Europe with an area of 90 to 100 km². For each of these catchments, we simulated a runoff hydrograph, using a simple Hortonian runoff model that routes water through the catchment based on previously proposed flow velocity equations. We made abstraction of rainfall patterns, lithology, land use and all factors other than topography. Hence, the hydrographs only reflect the influence of the morphological properties of the catchments and allow for comparisons. First results show that, apart from average catchment slope, there are very few regional patterns in catchment morphological properties that may significantly affect hydrographs. In some tectonically active regions, channel slopes are slightly steeper compared to catchments with the same average catchment slope in

  4. Household Arthropod Allergens in Korea

    PubMed Central

    Jeong, Kyoung Yong

    2009-01-01

    Arthropods are important in human health, which can transmit pathogens to humans, parasitize, or produce important allergens. Allergy prevalence becomes higher in Korea recently as well as other developed countries in contrast to a decrease of infectious diseases. Allergic diseases caused by household arthropods have increased dramatically during the last few decades since human beings spend more their time for indoor activities in modernized life style. Household arthropods are one of the most common causes of allergic diseases. Biological characterization of household arthropods and researches on their allergens will provide better understanding of the pathogenesis of allergic diseases and suggest new therapeutic ways. Therefore, studies on arthropods of allergenic importance can be considered one of the major research areas in medical arthropodology and parasitology. Here, the biology of several household arthropods, including house dust mites and cockroaches, the 2 most well known arthropods living indoor together with humans worldwide, and characteristics of their allergens, especially the research activities on these allergens performed in Korea, are summarized. PMID:19885330

  5. Occupational hearing loss in Korea.

    PubMed

    Kim, Kyoo Sang

    2010-12-01

    In this article, current status of noise exposure in workplaces, trend of workers with noise-induced hearing loss (NIHL), and prevalence of NIHL in workers by industry and job category in Korea were reviewed. In addition, trends of research on the audiological effects such as hearing loss from noise and occupational hearing loss from non-noise in Korea were addressed through reports in industrial audiology. Though noise exposure level has improved, noise still shows the highest rate of cases exceeding exposure limit among workplace hazards. NIHL is the most common occupational disease except work-related disease such as musculoskeletal disorders and cerebrovascular diseases, and NIHL prevalence is thought to be much higher than reported in official publications. Noise affecting hearing comes from various sources such as workplaces, military settings, areas with exposure to high noise, and specific noise sources. There is also occupational hearing loss by non-noise including chemicals such as organic solvents and heavy metals, barotrauma, and trauma due to welding spark. Noise affects daily life through audiological effects such as hearing loss and tinnitus, non-audiological physical effects (e.g., cardiovascular), and psychosocial and behavioral effects. Development of systematic and comprehensive hearing conservation programs for lowering the noise level in workplaces and preventing the NIHL, and preparation of technological, administrative system for its settlement at workplace are urgently needed.

  6. Nutrition policy in South Korea.

    PubMed

    Park, Hye-Kyung

    2008-01-01

    Since 1970s, the economic and social development in South Korea, as well as dietary pattern, has undergone various changes. Concerns for the decreased nutrition quality and physical activities among Koreans, especially young population, call for a need of a holistic approach in national food and nutrition policy. The National Health Promotion Act of 1995 included national interventions and programs to deal with nutrition-related chronic diseases and obesity prevention. A nation-wide monitoring system, which includes nutrition and health examination survey, is being built and run by the Ministry of Health and Welfare and its affiliated organizations every three years. The Korea Food and Drug Administration (KFDA) is another key agency undertaking national food and nutrition policies. The KFDA recently promulgated the national strategic plans for improving food safety and nutrition, focusing on children. Nutrition labelling policy for processed food is managed by KFDA and various education programs are developed and disseminated to enhance the awareness of nutrition labelling. The agency also makes standards and regulates foods for special dietary uses and health functional food. The Rural Development Administration (RDA) is responsible for maintaining the food composition database. Finally, the National School Lunch Program is mainly governed by the Ministry of Education and Human Resources Development. The above central government agencies along with regional health centers are making efforts to promote the healthy eating habits in addition to constructing healthy environment by making laws and programs and by research and social marketing.

  7. Occupational Skin Diseases in Korea

    PubMed Central

    Kim, Min-Gi

    2010-01-01

    Skin disease is the most common occupational disease, but the reported number is small in Korea due to a difficulty of detection and diagnosis in time. We described various official statistics and data from occupational skin disease surveillance system, epidemiological surveys and cases published in scientific journals. Until 1981, 2,222 cases of occupational skin disease were reported by Korean employee's regular medical check-up, accounting for 4.9% of the total occupational diseases. There was no subsequent official statistics to figure out occupational skin diseases till 1998. From 1999, the Korea Occupational Safety and Health Agency (KOSHA) published the number of occupational skin diseases through the statistics of Cause Investigation for Industrial Accidents. A total of 301 cases were reported from 1999 to 2007. Recent one study showed the figures of compensated occupational skin diseases. Many of them belonged to daily-paid workers in the public service, especially forestry workers. Also, it described the interesting cases such as vitiligo and trichloroethylene-induced Stevens-Johnson Syndrome. Skin diseases are still important though the number of cases has decreased, and therefore it is recommended to grasp the status of occupational skin diseases through continuous surveillance system and to make policy protecting high-risk group. PMID:21258591

  8. Occupational Hearing Loss in Korea

    PubMed Central

    2010-01-01

    In this article, current status of noise exposure in workplaces, trend of workers with noise-induced hearing loss (NIHL), and prevalence of NIHL in workers by industry and job category in Korea were reviewed. In addition, trends of research on the audiological effects such as hearing loss from noise and occupational hearing loss from non-noise in Korea were addressed through reports in industrial audiology. Though noise exposure level has improved, noise still shows the highest rate of cases exceeding exposure limit among workplace hazards. NIHL is the most common occupational disease except work-related disease such as musculoskeletal disorders and cerebrovascular diseases, and NIHL prevalence is thought to be much higher than reported in official publications. Noise affecting hearing comes from various sources such as workplaces, military settings, areas with exposure to high noise, and specific noise sources. There is also occupational hearing loss by non-noise including chemicals such as organic solvents and heavy metals, barotrauma, and trauma due to welding spark. Noise affects daily life through audiological effects such as hearing loss and tinnitus, non-audiological physical effects (e.g., cardiovascular), and psychosocial and behavioral effects. Development of systematic and comprehensive hearing conservation programs for lowering the noise level in workplaces and preventing the NIHL, and preparation of technological, administrative system for its settlement at workplace are urgently needed. PMID:21258593

  9. Resurgence of Mumps in Korea

    PubMed Central

    2015-01-01

    Routine vaccination against mumps has markedly reduced its incidence. However, the incidence of mumps continuously has increased since 2007. In 2013, a large mumps epidemic occurred in Korea, and this epidemic is still an ongoing problem. This epidemic occurred primarily in school settings and affected vaccinated adolescents, predominantly male students. The recent resurgence of mumps is caused by multiple factors: suboptimal effectiveness of the current mumps vaccines, use of the Rubini strain vaccine, waning immunity in the absence of natural boosting due to the marked reduction in the mumps incidence, genotype mismatch between the vaccine and circulating mumps virus strains, and environmental conditions that foster intense exposures. Containment of mumps outbreaks is challenging because the sensitivity of diagnostic tests is low among vaccinees and control measures are less efficient because of the inherent nature of the mumps virus. Despite the suboptimal vaccine effectiveness in outbreak settings, maintaining the high vaccine coverage is an important strategy to prevent mumps outbreaks, given that the routine use of mumps vaccines has substantially reduced the incidence of mumps and its complications as compared with that in the pre-vaccine era. In order to control the current mumps epidemic and prevent further outbreaks, we need to better understand the dynamics of mumps among vaccinated populations and the changing epidemiology in Korea. Concerted efforts should be made to systematically monitor the immunization status of the Korean population and to improve diagnosis efficiency. Furthermore, more effective mumps vaccines need to be developed in the future. PMID:25844258

  10. Convection and plate tectonics on extrasolar planets

    NASA Astrophysics Data System (ADS)

    Sotin, C.; Grasset, O.; Schubert, G.

    2012-04-01

    The number of potential Earth-like exoplanets is still very limited compared to the overall number of detected exoplanets. But the different methods keep improving, giving hope for this number to increase significantly in the coming years. Based on the relationship between mass and radius, two of the easiest parameters that can be known for exoplanets, four categories of planets have been identified: (i) the gas giants including hot Jupiters, (ii) the icy giants that can be like their solar system cousins Uranus and Neptune or that can have lost their H2-He atmosphere and have become the so-called ocean planets, (iii) the Earth-like planets with a fraction of silicates and iron similar to that of the Earth, and (iv) the Mercury like planet that have a much larger fraction of iron. The hunt for exoplanets is very much focused on Earth-like planets because of the desire to find alien forms of life and the science goal to understand how life started and developed on Earth. One science question is whether heat transfer by subsolidus convection can lead to plate tectonics, a process that allows material to be recycled in the interior on timescales of hundreds of millions of years. Earth-like exoplanets may have conditions quite different from Earth. For example, COROT-7b is so close to its star that it is likely locked in synchronous orbit with one very hot hemisphere and one very cold hemisphere. It is also worth noting that among the three Earth-like planets of the solar system (Earth, Venus and Mars), only Earth is subject to plate tectonics at present time. Venus may have experienced plate tectonics before the resurfacing event that erased any clue that such a process existed. This study investigates some of the parameters that can influence the transition from stagnant-lid convection to mobile-lid convection. Numerical simulations of convective heat transfer have been performed in 3D spherical geometry in order to determine the stress field generated by convection

  11. Toward a sustainable regional electricity system: The case of Kangwaon Province in Korea

    NASA Astrophysics Data System (ADS)

    Jung, Inwhan

    Korea's exceptional economic growth for the last three decades has been accompanied by a rapid growth in commercial energy use. While the world increased its total primary energy consumption by 1.7 percent annually during the period between 1971 and 1994, Korea expanded its consumption level by 8.5 percent during the same period. The first quarter of the twenty-first century will be a period when energy consumption in Korea escalates even further, particularly in electricity consumption. This projection raises potential conflicts between Korea's economic growth and Korea's participation in international efforts to reduce greenhouse gas (GHG) emissions (Noh, 1991). A sustainable energy system is likely to promote sustainable development. However, Korea's current electricity system mainly comprised of fossil fuels and nuclear power is unsustainable in the context of energy, environment, and economy (E3). As a means of addressing the problem, this study introduces the country's electricity system shaped by the actions of local regions. How a local region, such as Kangwon Province in Korea, might take steps to mitigate the problems associated with Korea's current electricity system? Reducing regional electricity requirements through end-use efficiency improvements in electric appliances, buildings, and industrial processes is fundamentally important. Decentralized and renewable-oriented electricity supply options are also important to the success of region-based sustainable electricity systems. This dissertation compares environmental and economic benefits between the conventional and sustainable electricity systems to meet electricity requirements in Kangwon Province in the year 2010. The results clearly indicate that the region-based sustainable electricity system gives significant benefits to the Province in terms of energy, economy, and environment. In the final chapter, policy guidelines are developed to implement region-based sustainable electricity plans.

  12. A convective forecast experiment of global tectonics

    NASA Astrophysics Data System (ADS)

    Coltice, Nicolas; Giering, Ralf

    2016-04-01

    Modeling jointly the deep convective motions in the mantle and the deformation of the lithosphere in a self-consistent way is a long-standing quest, for which significant advances have been made in the late 1990's. The complexities used in lithospheric models are making their way into the models of mantle convection (density variations, pseudo-plasticity, elasticity, free surface), hence global models of mantle motions can now display tectonics at their surface, evolving self-consistantly and showing some of the most important properties of plate tectonics on Earth (boundaries, types of boundaries, plate sizes, seafloor spreading properties, continental drift). The goal of this work is to experiment the forecasting power of such convection models with plate-like behavior, being here StagYY (Tackley, 2008). We generate initial conditions for a 3D spherical model in the past (50Ma and younger), using models with imposed plate velocities from 200Ma. By doing this, we introduce errors in the initial conditions that propagate afterwards. From these initial conditions, we run the convection models free, without imposing any sort of motion, letting the self-organization take place. We compare the forecast to the present-day plate velocities and plate boundaries. To investigate the optimal parameterization, and also have a flavor of the sensitivity of the results to rheological parameters, we compute the derivatives of the misfit of the surface velocities relative to the yield stress, the magnitude of the viscosity jump at 660km and the properties of a weak crust. These derivates are computed thanks to the tangent linear model of StagYY, that is built through the automatic differentiation software TAF (Giering and Kaminski, 2003). References Tackley, P. J., Modeling compressible mantle convection with large viscosity contrasts in a three-dimensional spherical shell using the yin-yang grid, Phys. Earth Planet. Inter. 171, 7-18 (2008). Giering, R., Kaminski, T., Applying TAF

  13. Tectonic development of Michigan basin

    SciTech Connect

    Prouty, C.E.

    1986-08-01

    The general form of the Michigan basin and surrounding frame structures - the Findlay, Kankakee, and Wisconsin arches - was inherited from the Precambrian. An ongoing study has provided new information on present basin configuration and the evolution of intrabasinal structures during the Paleozoic. This study involves: (1) isopach, structure contour, depocenter, and lithofacies map preparation; (2) diagenetic and epigenetic dolomitization processes and patterns; (3) Landsat imagery and lineament interpretation; (4) recognition of shearing mechanics and the resulting shear faulting and folding; and (5) the recognition of radial faults in contrast to shear faults. Monitoring of the above throughout the Paleozoic indicates that tectonic events within the basin were episodic in nature. Stresses are recognized as external and, through Fourier analysis of lineaments (shear faults), may be demonstrated as from the southeast, probably the Appalachian mobile belt. Shear faults are seated in Precambrian rocks, although they are probably not of that age. The faults occur with accompanying shear folds in rocks possibly as early as the Late Ordovician or Middle Silurian, but definitely by the Middle Devonian with the principal faulting and folding during the post-Osage Mississippian. Local shifting of the depocenter within the general Saginaw Bay area occurred during the early Paleozoic with a major shift westward to the present central basin position accompanied by the development of the present north-northwest ellipticity of the basin during the post-Osage, pre-Meramecian Mississippian. Barrier separation of the West Michigan Lagoon occurred in the Middle Ordovician and Middle and Late Devonian. Radial structures can be demonstrated in at least the Upper Silurian and Upper Devonian.

  14. Tectonic Discrimination with Classification Trees

    NASA Astrophysics Data System (ADS)

    Riedel, M.; Collett, T. S.; Malone, M.

    2005-12-01

    This presentation will report on the initial results of an Integrated Ocean Drilling Program (IODP) expedition to study the occurrence of gas hydrates along the Cascadia continental margin of North America. The abstract has been prepared in advance of the cruise and describes the primary objectives of this effort. IODP Expedition 311 (scheduled September 14 to October 29, 2005) has been designed to further constrain models for the formation of marine gas hydrate in subduction zone accretionary prisms. The objectives include characterizing the deep origin of the methane, its upward transport, its incorporation in gas hydrate, and its subsequent loss to the seafloor. The main attention of this expedition is on the widespread seafloor-parallel layer of dispersed gas hydrate located just above the base of the predicted stability field. In a gas hydrate formation model, methane is carried upward through regional sediment or small-scale fracture permeability, driven by the tectonic consolidation of the accretionary prism. The upward-moving methane is incorporated into the gas hydrate clathrate as it enters the methane hydrate stability zone. Also important is the focusing of a portion of the upward methane flux into localized plumes or channels to form concentrations of near-seafloor gas hydrate. The amount of gas hydrate in local concentrations near the seafloor is especially important for understanding the response of marine gas hydrate to climate change. The expedition includes coring and downhole measurements at a transect of five sites across the Northern Cascadia accretionary prism. The sites will track the history of methane in an accretionary prism from (1) its production by mainly microbiological processes over a thick sediment vertical extent, (2) its upward transport through regional or locally focused fluid flow, (3) its incorporation in the regional hydrate layer above the bottom-simulating reflector (BSR) or in local concentrations at or near the seafloor

  15. Tectonic evolution of northwest Siberia

    SciTech Connect

    Natapov, L.P. )

    1993-09-01

    The ancient Siberian continent was split from early Pangen in early Riphean. The newly formed continent drifted from the southern to the northern hemisphere, reaching high altitudes only in the Late Paleozoic. Up to the Early Carboniferous, a typical passive margin of the Atlantic type, prograding to the ocean, developed along the present northern and eastern boundaries of this continent. In Upper Paleozoic, Triassic, and Jurassic, the carbonate sedimentation was replaced by the accumulation of thick terrigenous complexes along the northern and southern margins. Large submarine plains were formed by the merging of fans, while eustatic lowering of the ocean level enlarged the source area of detrital material. Distal facies, with time, were moving into the ocean. Rifting, penetrating inside the continent, conditioned for formation of large sedimentary basins. The development of the Sukhanskaya syneclise is associated with Riphean rifting, and Vilyuiskaya with Upper Devonian rifting. In the Upper Mesozoic, the covergent boundaries of lithospheric plates existed along the northern and eastern boundaries of the Siberian continent. As a result of the final collision of the continental margin with blocks of different nature (microcontinents, island arcs, etc.) transported by the Kula plate, and with chukchi and north Taimyr arctic blocks, Verkhoyansk and Taimyr fold belts appeared in the Upper Cretaceous. They were over-thrusted on clastic wedges, putting into shape the present-day structure of foredeeps. In the paper, principal attention is devoted to peculiarities of structure and development of sedimentary basins, formation of oil-producing complexes, and structures favorable for accumulation of hydrocarbons. All these features are analyzed at the background of this plate tectonic scenario.

  16. Future change of climate classification over South Korea in multi regional climate simulations

    NASA Astrophysics Data System (ADS)

    Lee, Hyeon-Jae; Kim, Gayoung; Park, Changyong; Cha, Dong-Hyun

    2017-04-01

    Regional climate simulations for the CORDEX East Asia domain were conducted between 1981 and 2100 using five models to produce climate change projection based on RCP26, 45, 60, 85 scenarios. In this study using the ensemble of five model results, future changes in climate zones of South Korea were investigated according to Köppen-Trewartha's classification criteria. Four periods, historical (1981 2005), early future (2021 2040), middle future (2041 2070), and late future (2071 2100) were analyzed to examine future changes. In historical (1981 2005) period, the subtropical zones are only dominant in the south coastal regions and Jeju island, while those tend to expand in the future periods. Depending on the RCP scenarios, the more radiative forcing results in the larger subtropical zone over South Korea. The expansion of the subtropical zone in metropolitan areas is more evident than that in rural areas. In addition, the enlargement of subtropical zone in coastal regions is more prominent that in inland regions. Particularly, the subtropical climate zone for the late future period of RCP85 scenario is significantly dominant in most South Korea. Acknowledgement The research was supported by the Korea Meteorological Administration Research and Development program under grant KMIPA 2015-2083 and the National Research Foundation of Korea Grant funded by the Ministry of Science, ICT and Future Planning of Korea (NRF-2016M3C4A7952637) for its support and assistant in completion of the study.

  17. Burden of noncommunicable diseases and national strategies to control them in Korea.

    PubMed

    Khang, Young-Ho

    2013-07-01

    Noncommunicable diseases (NCDs) are the most important causes of premature mortality and disability-adjusted life years in Korea. NCDs are also the main contributor to socioeconomic inequalities in mortality and life expectancy. Reduction of NCDs and NCD inequalities would result in significant improvement in healthy life expectancy and health equity in Korea. Major NCD risk factors such as dietary risks (including salt intake), alcohol consumption, cigarette smoking, and high blood pressure were found to be the leading modifiable risk factors of disability-adjusted life years in Korea, based on the 2010 Global Burden of Disease Study. Several Korean studies have shown that these risk factors play an important role in creating socioeconomic inequalities in NCD mortality and total mortality. Current international discussions on NCD policies in the United Nations and the World Health Organization would provide better opportunities for developing aggressive population-wide policy measures in Korea. Considering the paucity of population-wide policies to control major NCD risk factors in Korea, rigorous population approaches such as taxation and regulation of unhealthy commodities as well as public education and mass campaigns should be further developed in Korea.

  18. Copycat Suicide Induced by Entertainment Celebrity Suicides in South Korea

    PubMed Central

    Jang, Soo Ah; Sung, Ji Min; Park, Jin Young

    2016-01-01

    Objective Throughout the past several years, there have been a number of entertainment celebrity suicides in South Korea. The aim of this study was to investigate the clustering of suicides following celebrities' suicides in South Korea from 2005 to 2008, particularly according to certain characteristics. Methods Seven celebrity suicides were examined and defined using the Korean Integrated Newspaper Database System (KINDS) and from these, we considered four affected periods occurring 28 days after each celebrity's suicide. A Poisson time-series autoregression model was used to estimate the relative risk of the total suicide number for each affected period from 2005 to 2008. Logistic regression analysis was performed to investigate whether there were specific increases in the numbers of suicides in subgroups matching each celebrity. Results There were significant increases in the risk of suicide during the affected periods. Remarkable increases were found in the subgroups matching each celebrity, especially in the group in which all factors (sex, age, and method) were similar. Conclusion This study provides confirmation that a significant copycat effect was induced by these celebrities' suicides, especially among people who identified more with the celebrities. This implies that countermeasures for upright media coverage of celebrity suicides should be discussed and practiced properly in South Korea. PMID:26766949

  19. Copycat Suicide Induced by Entertainment Celebrity Suicides in South Korea.

    PubMed

    Jang, Soo Ah; Sung, Ji Min; Park, Jin Young; Jeon, Woo Taek

    2016-01-01

    Throughout the past several years, there have been a number of entertainment celebrity suicides in South Korea. The aim of this study was to investigate the clustering of suicides following celebrities' suicides in South Korea from 2005 to 2008, particularly according to certain characteristics. Seven celebrity suicides were examined and defined using the Korean Integrated Newspaper Database System (KINDS) and from these, we considered four affected periods occurring 28 days after each celebrity's suicide. A Poisson time-series autoregression model was used to estimate the relative risk of the total suicide number for each affected period from 2005 to 2008. Logistic regression analysis was performed to investigate whether there were specific increases in the numbers of suicides in subgroups matching each celebrity. There were significant increases in the risk of suicide during the affected periods. Remarkable increases were found in the subgroups matching each celebrity, especially in the group in which all factors (sex, age, and method) were similar. This study provides confirmation that a significant copycat effect was induced by these celebrities' suicides, especially among people who identified more with the celebrities. This implies that countermeasures for upright media coverage of celebrity suicides should be discussed and practiced properly in South Korea.

  20. Significant release of shear energy of the North Korean nuclear test on February 12, 2013

    NASA Astrophysics Data System (ADS)

    Barth, Andreas

    2014-07-01

    On February 12, 2013 the Democratic People's Republic of Korea (DPRK) carried out an announced nuclear test, which was the third after tests conducted in 2006 and 2009. An important task in discriminating a man-made explosion and a natural tectonic earthquake is the analysis of seismic waveforms. To determine the isotropic and non-isotropic characteristics of the detonation source, I invert long-period seismic data for the full seismic moment tensor to match the observed seismic signals by synthetic waveforms based on a 3D Earth model. Here, I show that the inversion of long-period seismic data of the 2013 test reveals a clear explosive (isotropic) component combined with a significant release of shear energy by the double-couple part of the moment tensor. While the isotropic part of the nuclear test in 2009 was similar to that in 2013, the double-couple part was lower by a factor of 0.55 compared to the explosion in 2013. Moreover, the ratio of the isotropic seismic moments of the 2013 and 2009 nuclear tests is 1.4 ± 0.1 and lower than published estimations of the yield ratio, which indicates the importance of considering the release of shear energy. The determined orientation of the double-couple fault plane is parallel to the dominating geologic fault structures NNE-SSW to NE-SW, but the calculated normal faulting mechanism does not correspond to the general tectonic strike-slip regime. Thus, explanations for the enhanced release of shear energy might be induced dip-slip motion pre-stressed by the previous test or near source damaging effects due to a changed containment of the nuclear explosion.

  1. Recommendations for Carotid Stenting in Korea

    PubMed Central

    Chang, Hyuk Won; Suh, Sang-il; Jeong, Hae Woong; Suh, Dae Chul

    2015-01-01

    Carotid artery angioplasty with stenting (CAS) is being performed in many hospitals in Korea. Most of the guidelines which are being used are similar, but the practical aspects such as techniques are different between hospitals. For example, usage of various protective devices, the oral antiplatelet regimen prior to procedure and placing of temporary pacemaker to prevent bradycardia are different between hospitals. In this article, we summarize and propose the guidelines for CAS which is currently being accepted in Korea. These guidelines may be helpful in providing protocol to neurointerventionalist who perform CAS and to standardize the process including reporting of CAS in the future comparative trials in Korea. PMID:25763292

  2. Origin of adakite-like plutons in southern Korea

    NASA Astrophysics Data System (ADS)

    Oh, Jeong-Im; Choi, Sung Hi; Yi, Keewook

    2016-10-01

    We present Sr-Nd-Pb isotopic compositions for two adakite-like intrusions in southern Korea (Jindong and Bongnae), including major and trace element concentrations, and the sensitive high-resolution ion microprobe (SHRIMP) zircon U-Pb age. Our aim is to constrain the origin and tectonomagmatic processes that gave rise to the plutons. A SHRIMP U-Pb zircon age of 88.7 ± 0.7 Ma was obtained from a Jindong granodiorite sample. The Jindong plutons belong to the medium-K calc-alkaline series, and have an overall enrichment in large ion lithophile elements (LILE), such as K, Rb, Ba, and Pb, and a relative depletion in high field strength elements, such as Nb, Ta, and Ti, compared with the neighboring elements in the primitive mantle-normalized multi-trace element variation diagram. It was found that (87Sr/86Sr)i = 0.70475-0.70596, (143Nd/144Nd)i = 0.512547-0.512604, [(εNd)i = + 0.4 to 2.2], and (206Pb/204Pb)i = 18.19-18.37, which fall within the field of the arc-type Cretaceous to Tertiary Bulguksa intrusive rocks in the Sr-Nd and Pb-Pb isotopic correlation diagrams. The elevated Sr/Y (17-40), but low La/Yb (3.7-8.8) ratios of the Jindong plutons, together with their coherent geochemical trends and U-shaped rare earth element (REE) patterns, indicate that they were not formed by slab melting, but by amphibole-dominated fractional crystallization of the Bulguksa-like arc magma. A SHRIMP U-Pb zircon age of 226.5 ± 2.5 Ma was obtained from a Bongnae tonalite sample. The Bongnae plutons belong to the shoshonitic series. Their trace element patterns resemble the Jindong samples, but are characterized by significantly negative U anomalies in mafic rocks. They also have elevated MgO, Ni, Co, Cr, Rb, Ba, Sr, and low Al2O3 and Na2O contents at a given SiO2 concentration compared with the Jindong plutons, and are typified by highly radiogenic Sr and unradiogenic Nd and Pb isotopic compositions: [(87Sr/86Sr)i = 0.71096-0.71290, (143Nd/144Nd)i = 0.511641-0.511681, (εNd)i = - 13

  3. Tectonic aspects of Precambrian metallogeny of gold and uranium

    NASA Astrophysics Data System (ADS)

    Glukhovskii, M. Z.; Velichkin, V. I.; Shumilin, M. V.

    2017-01-01

    A cause-and-effect relation is established between historical metallogeny of gold and uranium and extraterrestrial factors (impact events, evolution of the distance between Earth and Moon, rotation geodynamics), which significantly affected the Early Precambrian tectonic evolution of our planet. It is shown by the example of the complex Witwatersrand deposit that the Precambrian polygenetic Au and U deposits of the quartz-pebble type were formed within a near-equatorial epi-Archean supercontinent and were related to extraterrestrial factors under a rotation regime of the plume vertical tectonics. The beginning of breakup of the epi-Archean supercontinent in the Paleo- and Mesoproterozoic (2.0 ± 0.3 Ga) was related to the abrupt decrease in the velocity of the Earth's axial rotation followed by the dominant regime of subhorizontal plate tectonics and formation of rich U deposits of the nonconformity type (which are structurally related to the horizontal inertial detachments at the contacts of the consolidated crust) and Meso- and Neoproterozoic sedimentary complexes.

  4. Drip Tectonics and The Uplift of Central Anatolia

    NASA Astrophysics Data System (ADS)

    Gogus, O.; Pysklywec, R.; Sengor, A. M. C.; Gun, E.

    2016-12-01

    The uplift of Central Anatolia over the last 8-10 m.y. is associated with a broad 1 km plateau, with higher elevations at the north (Pontides) and the south (Taurides) margins. A number of geophysical, petrological and geological evidence suggests that the Central Anatolian (Kırşehir) arc root was removed 10 Myrs ago. To investigate the role of potential arc root removal process in the style of drip tectonics, a series of numerical experiments are conducted. Model predictions are tested against a range of geological and geophysical observables from Central Anatolia. Numerical models demonstrate that an arc root removal event has a distinct spatial and temporal effect in the crust resulting in plateau uplift > 1 km. The vertical loading and crustal deformation change during drip evolution. Lithospheric rheology and plate convergence can significantly modify the magnitude and length scale of the uplift. This drip tectonics process is in good agreement with the geologic evidence for the broad plateau uplift of Central Anatolia, as well as seismic data showing thin or missing lithosphere and a remnant structure characteristic of a removal event. While this research focuses on the Late Cenozoic geodynamic evolution of Central Anatolia, the outcome of this work may have general implications for the development of other orogenic areas where compelling documentation on drip tectonics has been interpreted (e.g., Central Andes, Tibet, Sierra Nevada, Colorado plateau, Mediterranean Alpides).

  5. Tectonic regime and deformation bands properties in porous sandstone

    NASA Astrophysics Data System (ADS)

    Soliva, Roger; Ballas, Gregory; Fossen, Haakon; Philit, Sven

    2017-04-01

    Porous sandstones tend to deform by the formation of low-permeable deformation bands that influence fluid flow in reservoir settings. The bands may be distributed or localized into clusters, and limited recent data suggest that tectonic regime may exert a control on their distribution and clustering. In order to explore this suggestion, we performed a synthetic analysis based of 73 sets of bands, including 22 new sets measured for reverse Andersonian regime that significantly fill the important gap of data for this context. We find a surprisingly strong correlation between clustering and tectonic regime, where bands clearly are more distributed in the reverse regime compared to the normal regime. Together with the observed band distributions, microstructures and capillary pressure data show evidence that efficient membrane seals are promoted for extension, whereas pervasive permeability anisotropy is expected for contraction. Such a basic new rule concerning tectonic regime is very useful for assessment of reservoirs properties where deformation bands are common but below seismic resolution.

  6. Tectonic control of coastal onlap cycles, southwest Washington

    SciTech Connect

    Armentrout, J.M.

    1987-05-01

    Local coastal onlap and paleobiobathymetric curves for 14 sections define three Cenozoic depositional onlap-offlap cycles separated by regionally significant unconformities. A paleoclimatic curve for western Oregon and Washington, based on paleoecologic data sets, demonstrates that the local transgressions are coincident with cool climates and the regressions with warm climates, and are therefore not driven by glacioeustatic cycles. Comparison of the local coastal onlap and paleobiobathymetric curves with the global Cenozoic Cycle Chart (modified Exxon Sea Level Chart - May, 1986) further demonstrates the uniqueness of the western Washington curves. The global Cenozoic cycle Chart curve represents coastal onlap and sea level curves based on integration of both climate and tectonic variations. The non-parallel cycle pattern for southwest Washington suggests a unique tectonically forced system. Evidence derived from stratigraphic sequences, igneous rock geochemistry, radiometric dating, remnant magnetic patterns, sandstone provenance studies, and paleogeographic reconstructions is used to identify the tectonic events controlling the local depositional cycles. The principal events are (1) middle Eocene accretion of a seamount chain; (2) early-late Eocene westward relocation of subduction; (3) late Eocene onset of Cascade arc volcanism; (4) late-early Miocene plate readjustment due to back-arc extension in the Columbia River Plateau and Great Basin; and (5) late Pliocene to early Pleistocene northeast compression forced by continued subduction of remnants of the Kula Plate beneath North America.

  7. Korea`s choice of a new generation of nuclear plants

    SciTech Connect

    Redding, J.R.

    1994-12-31

    The ABWR and SBWR design, both under development at GE, provide the best platform for developing the next generation advanced plants. The ABWR, which is rapidly setting the standard for new nuclear reactor plants, is clearly the best choice to meet the present energy needs of Korea. And through a GE/Korea partnership to develop the plant of the next century, Korea will establish itself as a leader in innovative reactor technology.

  8. Thick-skinned tectonics closing the Rifian Corridor

    NASA Astrophysics Data System (ADS)

    Capella, Walter; Matenco, Liviu; Dmitrieva, Evelina; Roest, Wilmer M. J.; Hessels, Suzanne; Hssain, Mohamed; Chakor-Alami, Abdelwahid; Sierro, Francisco J.; Krijgsman, Wout

    2017-07-01

    Tectonic processes in the Gibraltar region are associated with Africa-Iberia convergence and the formation of the Betic-Rif orogenic system. The Late Miocene shortening recorded in the Rif orogen resulted in gradual shallowing and eventual closure of the Rifian Corridor, a narrow marine gateway connecting the Atlantic Ocean with the Mediterranean Sea. This closure is associated with paleoenvironmental changes that ultimately led to the Mediterranean Messinian Salinity Crisis. Here we present a structural analysis based on a combination of field kinematic data and interpretation of reflection seismic lines acquired for petroleum exploration to understand the deformational phases associated with the closure of the Rifian Corridor. We show the succession of three Late Miocene to present day events, an initial thin-skinned nappe thrusting, followed by regional subsidence and continued by thick-skinned contraction. The transition from in sequence thin-skinned tectonics during subduction to thick-skinned contraction during continental collision resulted in significant acceleration of tectonic uplift and associated exhumation. This is related to a change in the regional deformation linked to plate convergence, but possibly also coupled with deep lithospheric or dynamic topography processes. Such a mechanism is also common for other Mediterranean orogens during late stages of slab retreat, where accelerated tectonics resulted in rapid sedimentation and associated basins evolution. We conclude that the thick-skinned contraction in the Rif orogeny initiated in the late Tortonian, has created a cumulative uplift in the order of 1 km, and provided high enough uplift rates to close the Rifian Corridor.

  9. Surface-wave potential for triggering tectonic (nonvolcanic) tremor

    USGS Publications Warehouse

    Hill, D.P.

    2010-01-01

    Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle is anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45?? incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia mega-thrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction, ????? 0.2). However, documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, is associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (?? ~ 0.6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

  10. Red Sea Kinematics in Relation to the Regional Tectonics Setting

    NASA Astrophysics Data System (ADS)

    Alotaibi, T.; Furlong, K. P.

    2015-12-01

    The Red sSea extensional system started approximately 22+3 Ma. Although, there is evidence that lithospheric weakening and associated incipient extension may have taken place since 30 Ma. There is oceanic crust found in the southern part of the rift, while the northern-most part still involves continental stretching. Meantime magnetic anomalies have been observed for the southern rift, the northern rift is characterized by several deeps where magnetic anomalies have been observed as well as an indication of the transition from continental to oceanic rifting. GPS stations along the Red Sea are consistent with kinematics implied from the magnetic anomalies - an opening rate in the southern part of ~ 15 mm/yr relative to Eurasia fixed while the opening rate in the is ~8 mm/yr. This significant decreasing of the opening rate towards the north implies complexity within the Red Sea extensional system.Our purpose here is to place the Red Sea extensional kinematics within the regional tectonics context by combining constraints on the rate or style of extension within the Red Sea with tectonic activities on the adjacent continental regions. To accomplish this, we will model the extensional kinematics through time by comparing recent kinematics based on the geophysical observations with ones that based on geological observations. In terms of present-day geophysical observations, we have GPS and magnetic anomalies data, and crustal and lithospheric thickness. Geological observations primarily come from stratigraphic and structural data sets.Our overall target is to construct a tectonic model that links the timing of the change in the style and extensional rate with the tectonic activities in Afar, Gulf of Aden, Zagros, Dead Sea fault and Anatolian region.

  11. Revisiting Tectonic Corrections Applied to Pleistocene Sea-Level Highstands

    NASA Astrophysics Data System (ADS)

    Creveling, J. R.; Mitrovica, J. X.; Hay, C.; Austermann, J.; Kopp, R. E.

    2015-12-01

    The robustness of stratigraphic- and geomorphic-based inferences of Quaternary peak interglacial sea levels — and equivalent minimum continental ice volumes — depends on the accuracy with which highstand markers can be corrected for vertical tectonic displacement. For sites that preserve a Marine Isotope Stage (MIS) 5e sea-level highstand marker, the customary method for estimating tectonic uplift/subsidence rate computes the difference between the local elevation of the highstand marker and a reference eustatic (i.e., global mean) MIS 5e sea-level height, typically assumed to be +6 m, and then divides this height difference by the age of the highstand marker. This rate is then applied to correct the elevation of other observed sea-level markers at that site for tectonic displacement. Subtracting a reference eustatic value from a local MIS 5e highstand marker elevation introduces two potentially significant errors. First, the commonly adopted peak eustatic MIS 5e sea-level value (i.e., +6 m) is likely too low; recent studies concluded that MIS 5e peak eustatic sea level was ~6-9 m. Second, local peak MIS 5e sea level was not globally uniform, but instead characterized by significant departures from eustasy due to glacial isostatic adjustment (GIA) in response to successive glacial-interglacial cycles and excess polar ice-sheet melt relative to present day. We present numerical models of GIA that incorporate both of these effects in order to quantify the plausible range in error of previous tectonic corrections. We demonstrate that, even far from melting ice sheets, local peak MIS 5e sea level may have departed from eustasy by 2-4 m, or more. Thus, adopting an assumed reference eustatic value to estimate tectonic displacement, rather than a site-specific GIA signal, can introduce significant error in estimates of peak eustatic sea level (and minimum ice volumes) during Quaternary highstands (e.g., MIS 11, MIS 5c and MIS 5a).

  12. Seaweed Farms in South Korea

    NASA Image and Video Library

    2017-09-28

    The dark squares that make up the checkerboard pattern in this image are fields of a sort—fields of seaweed. Along the south coast of South Korea, seaweed is often grown on ropes, which are held near the surface with buoys. This technique ensures that the seaweed stays close enough to the surface to get enough light during high tide but doesn’t scrape against the bottom during low tide. The Operational Land Imager (OLI) on Landsat 8 acquired this image of seaweed cultivation in the shallow waters around Sisan Island on January 31, 2014. Home to a thriving aquaculture industry, the south coast of South Korea produces about 90 percent of the country’s seaweed crop. The waters around Sisan are not the only place where aquaculture is common. View the large image to see how ubiquitous seaweed aquaculture is along the coast in Jeollanam-do, the southernmost province on the Korean peninsula. Two main types of seaweed are cultivated in South Korea: Undaria (known as miyeok in Korean, wakame in Japanese) and Pyropia (gim in Korean, nori in Japanese). Both types are used generously in traditional Korean, Japanese, and Chinese food. Since 1970, farmed seaweed production has increased by approximately 8 percent per year. Today, about 90 percent of all the seaweed that humans consume globally is farmed. That may be good for the environment. In comparison to other types of food production, seaweed farming has a light environmental footprint because it does not require fresh water or fertilizer. NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey. Caption by Adam Voiland. Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission

  13. Time-domain study of tectonic strain-release effects on seismic waves from underground nuclear explosions

    SciTech Connect

    Nakanishi, K.K.; Sherman, N.W.

    1982-09-01

    Tectonic strain release affects both the amplitude and phase of seismic waves from underground nuclear explosions. Surface wave magnitudes are strongly affected by the component of tectonic strain release in the explosion. Amplitudes and radiation patterns of surface waves from explosions with even small tectonic components change magnitudes significantly and show a strong dependence on receiver locations. A thrust-slip source superimposed on an isotropic explosion can explain observed reversals in waveform at different azimuths and phase delays between normal and reversed Rayleigh waves. The mechanism of this reversal is due to the phase relationship between reasonable explosion and tectonic release sources. Spallation or an unusual source time function are not required. The observations of Shagan River events imply thrust-slip motion along faults in a northwest-southeast direction, which is consistent with regional tectonics.

  14. Republic of Korea`s security in northeast Asia. Regional strategic appraisal

    SciTech Connect

    Jung, S.J.

    1996-04-15

    Although the Cold War is over, the security environment in Northeast Asia is not stable. This study summarizes Korea`s national interests from a Korean soldier`s perspective. The threats and issues are described according to the format of a regional strategic appraisal. This study recommends the organization of a Conference on Security and Cooperation in Northeast Asia (CSCNEA). This organization would be composed of the two Koreas(or eventually a reunified Korea), the United States, Japan, China, and Russia. Before the establishment of the organization, the enlargement of bilateral cooperation is recommended.

  15. Tectonics of the Outer Planet Satellites

    NASA Technical Reports Server (NTRS)

    McKinnon, W. B.; Collins, G. C.; Moore, J. M.; Nimmo, F.; Pappalardo, R. T.; Prockter, L. M.; Schenk, P. M.

    2010-01-01

    Tectonic features on the satellites of the outer planets range from the familiar, such as clearly recognizable graben on many satellites, to the bizarre, such as the ubiquitous double ridges on Europa, the twisting sets of ridges on Triton, or the isolated giant mountains rising from Io's surface. All of the large and middle-sized outer planet satellites except Io are dominated by water ice near their surfaces. Though ice is a brittle material at the cold temperatures found in the outer solar system, the amount of energy it takes to bring it close to its melting point is lower than for a rocky body. Therefore, some unique features of icy satellite tectonics may be influenced by a near-surface ductile layer beneath the brittle surface material, and several of the icy satellites may possess subsurface oceans. Sources of stress to drive tectonism are commonly dominated by the tides that deform these satellites as they orbit their primary giant planets. On several satellites, the observed tectonic features may be the result of changes in their tidal figures, or motions of their solid surfaces with respect to their tidal figures. Other driving mechanisms for tectonics include volume changes due to ice or water phase changes in the interior, thermoelastic stress, deformation of the surface above rising diapirs of warm ice, and motion of subsurface material toward large impact basins as they fill in and relax. Most satellites exhibit evidence for extensional deformation, and some exhibit strike-slip faulting, whereas contractional tectonism appears to be rare. Io s surface is unique, exhibiting huge isolated mountains that may be blocks of crust tilting and foundering into the rapidly emptying interior as the surface is constantly buried by deposits from hyperactive volcanoes. Of the satellites, diminutive Enceladus is spectacularly active; its south polar terrain is a site of young tectonism, copious heat flow, and tall plumes venting into space. Europa's surface is

  16. Tectonics of the Outer Planet Satellites

    NASA Technical Reports Server (NTRS)

    McKinnon, W. B.; Collins, G. C.; Moore, J. M.; Nimmo, F.; Pappalardo, R. T.; Prockter, L. M.; Schenk, P. M.

    2010-01-01

    Tectonic features on the satellites of the outer planets range from the familiar, such as clearly recognizable graben on many satellites, to the bizarre, such as the ubiquitous double ridges on Europa, the twisting sets of ridges on Triton, or the isolated giant mountains rising from Io's surface. All of the large and middle-sized outer planet satellites except Io are dominated by water ice near their surfaces. Though ice is a brittle material at the cold temperatures found in the outer solar system, the amount of energy it takes to bring it close to its melting point is lower than for a rocky body. Therefore, some unique features of icy satellite tectonics may be influenced by a near-surface ductile layer beneath the brittle surface material, and several of the icy satellites may possess subsurface oceans. Sources of stress to drive tectonism are commonly dominated by the tides that deform these satellites as they orbit their primary giant planets. On several satellites, the observed tectonic features may be the result of changes in their tidal figures, or motions of their solid surfaces with respect to their tidal figures. Other driving mechanisms for tectonics include volume changes due to ice or water phase changes in the interior, thermoelastic stress, deformation of the surface above rising diapirs of warm ice, and motion of subsurface material toward large impact basins as they fill in and relax. Most satellites exhibit evidence for extensional deformation, and some exhibit strike-slip faulting, whereas contractional tectonism appears to be rare. Io s surface is unique, exhibiting huge isolated mountains that may be blocks of crust tilting and foundering into the rapidly emptying interior as the surface is constantly buried by deposits from hyperactive volcanoes. Of the satellites, diminutive Enceladus is spectacularly active; its south polar terrain is a site of young tectonism, copious heat flow, and tall plumes venting into space. Europa's surface is

  17. Plate tectonics on the early Earth: Limitations imposed by strength and buoyancy of subducted lithosphere

    NASA Astrophysics Data System (ADS)

    van Hunen, Jeroen; van den Berg, Arie P.

    2008-06-01

    The tectonic style and viability of modern plate tectonics in the early Earth is still debated. Field observations and theoretical arguments both in favor and against the uniformitarian view of plate tectonics back until the Archean continue to accumulate. Here, we present the first numerical modeling results that address for a hotter Earth the viability of subduction, one of the main requirements for plate tectonics. A hotter mantle has mainly two effects: 1) viscosity is lower, and 2) more melt is produced, which in a plate tectonic setting will lead to a thicker oceanic crust and harzburgite layer. Although compositional buoyancy resulting from these thick crust and harzburgite might be a serious limitation for subduction initiation, our modeling results show that eclogitization significantly relaxes this limitation for a developed, ongoing subduction process. Furthermore, the lower viscosity leads to more frequent slab breakoff, and sometimes to crustal separation from the mantle lithosphere. Unlike earlier propositions, not compositional buoyancy considerations, but this lithospheric weakness could be the principle limitation to the viability of plate tectonics in a hotter Earth. These results suggest a new explanation for the absence of ultrahigh-pressure metamorphism (UHPM) and blueschists in most of the Precambrian: early slabs were not too buoyant, but too weak to provide a mechanism for UHPM and exhumation.

  18. Tectonic evolution of the Arctic shelf of Siberia from Riphean through Mesozoic time

    SciTech Connect

    Gramberg, I.S.; Kos'ko, M.K.; Pogrebitskiy, Yu.E.

    1986-08-01

    Paleotectonic structures are a most important factor to be considered during geological exploration for oil, gas, and other mineral resources, particularly for studies in the vast, but poorly accessible Arctic shelves. The authors have treated the paleotectonic evolution of the Arctic shelves of Siberia on the basis, of a three-dimensional tectonic model of the region, which consists of an assemblage of tectonic maps for specific stages, each representing a specific surface within the sedimentary-metamorphic envelope. The surfaces mapped in each case correspond to the top of one of the tectonic megacomplexes (Baykalian, Caledonian, and early Hercynian, late Hercynian, and Mesozoic) and reflect levels of the most significant gross changes in the crustal evolution of Siberia. The megacomplexes in their turn consist of tectonic complexes, separable on the basis of structural-material characteristics, which reflect a particular tectonic regime. As a synthesis of modern geological and geophysical data, the assemblage of tectonic maps depicts the principal features of the evolution of the Arctic shelves in Siberia during the Riphean-Mesozoic interval, that is, prior to the development of the oceanic basins and the formation of a specific syn-oceanic complex of Danian-Quaternary sediments on the shelves. 15 references.

  19. Space Weather Services of Korea

    NASA Astrophysics Data System (ADS)

    Yoon, K.; Hong, S.; Park, S.; Kim, Y. Y.; Wi, G.

    2015-12-01

    The Korean Space Weather Center (KSWC) of the National Radio Research Agency (RRA) is a government agency which is the official source of space weather information for Korean Government and the primary action agency of emergency measure to severe space weather condition. KSWC's main role is providing alerts, watches, and forecasts in order to minimize the space weather impacts on both of public and commercial sectors of satellites, aviation, communications, navigations, power grids, and etc. KSWC is also in charge of monitoring the space weather condition and conducting research and development for its main role of space weather operation in Korea. In this study, we will present KSWC's recent efforts on development of application-oriented space weather research products and services on user needs, and introduce new international collaborative projects, such as IPS-Driven Enlil model, global network of DSCOVR and STEREO satellites tracking, and ARMAS (Automated Radiation Measurement for Aviation Safety).

  20. Space Weather Services of Korea

    NASA Astrophysics Data System (ADS)

    Yoon, KiChang; Kim, Jae-Hun; Kim, Young Yun; Kwon, Yongki; Wi, Gwan-sik

    2016-07-01

    The Korean Space Weather Center (KSWC) of the National Radio Research Agency (RRA) is a government agency which is the official source of space weather information for Korean Government and the primary action agency of emergency measure to severe space weather condition. KSWC's main role is providing alerts, watches, and forecasts in order to minimize the space weather impacts on both of public and commercial sectors of satellites, aviation, communications, navigations, power grids, and etc. KSWC is also in charge of monitoring the space weather condition and conducting research and development for its main role of space weather operation in Korea. In this study, we will present KSWC's recent efforts on development of application-oriented space weather research products and services on user needs, and introduce new international collaborative projects, such as IPS-Driven Enlil model, DREAM model estimating electron in satellite orbit, global network of DSCOVR and STEREO satellites tracking, and ARMAS (Automated Radiation Measurement for Aviation Safety).

  1. Space Weather Services of Korea

    NASA Astrophysics Data System (ADS)

    Yoon, K.; Hong, S.; Jangsuk, C.; Dong Kyu, K.; Jinyee, C.; Yeongoh, C.

    2016-12-01

    The Korean Space Weather Center (KSWC) of the National Radio Research Agency (RRA) is a government agency which is the official source of space weather information for Korean Government and the primary action agency of emergency measure to severe space weather condition. KSWC's main role is providing alerts, watches, and forecasts in order to minimize the space weather impacts on both of public and commercial sectors of satellites, aviation, communications, navigations, power grids, and etc. KSWC is also in charge of monitoring the space weather condition and conducting research and development for its main role of space weather operation in Korea. In this study, we will present KSWC's recent efforts on development of application-oriented space weather research products and services on user needs, and introduce new international collaborative projects, such as IPS-Driven Enlil model, DREAM model estimating electron in satellite orbit, global network of DSCOVR and STEREO satellites tracking, and ARMAS (Automated Radiation Measurement for Aviation Safety).

  2. Iapetus: Tectonic structure and geologic history

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1991-01-01

    Many papers have been written about the surface of Iapetus, but most of these have discussed either the nature of the strongly contrasting light and dark materials or the cratering record. Little has been said about other geologic features on Iapetus, such as tectonic structures, which would provide constraints on Iapetus' thermal history. Most references have suggested that there is no conclusive evidence for any tectonic activity, even when thermal history studies indicate that there should be. However, a new study of Iapetus' surface involving the use of stereo pairs, an extensive tectonic network has been recognized. A few new observations concerning the craters and dark material were also made. Thus the geology and geologic history of Iapetus can be more fully outlined than before. The tectonic network is shown along with prominent craters and part of the dark material in the geologic/tectonic sketch map. The topology of crater rims and scarps are quite apparent and recognizable in the different image pairs. The heights and slopes of various features given are based on comparison with the depths of craters 50 to 100 km in diameter, which are assumed to have the same depths as craters of similar diameter on Rhea and Titania.

  3. Phanerozoic tectonic evolution of Tarim Basin

    SciTech Connect

    Sun Zhaocai; Zhang Yigang

    1995-08-01

    The tectonic evolution of Tarim Basin can be divided into two stages. In the first stage, there developed three Palaeozoic sequences (Pt3-01, O2-3-D and C1-P2), the deposition of which were controlled by Palaeoasian Tectonic Domain. In the second stage, there appeared five Meso-Cenozoic sequences (T1-2, T3, J, K2-E and N1-Q), controlled by Tethys Sea Tectonic Domain. Both of the first sequence of each stage (Pt3-01 and T1-2) are of typical rift-drift facies, overlain by flexural facies. The Palaeozoic tectonic style is characterized by basement-involved, back-thrusted uplifts and the pop-up held inbetween them. The main tectonic style since Late Triassic time has been thin-skin decoupling anticlines developed near the deep troughs in the foreland basins. Corresponding to the two above-mentioned stages, two major petroleum systems were formed. However, the early petroleum system was partly destroyed due to the marked overturn of the basin during Late Palaeozoic time.

  4. Surface Geology and Tectonism on Enceladus

    NASA Astrophysics Data System (ADS)

    Helfenstein, P.; Thomas, P. C.; Veverka, J.; Porco, C.; Giese, B.; Wagner, R.; Roatsch, T.; Denk, T.; Neukum, G.; Turtle, E.

    2006-12-01

    Enceladus is remarkable not only for its active water-ice eruptions near the South Pole, but also because its surface geology preserves a system of large-scale tectonic patterns that record past, as well as present centers of tectonic deformation. The currently active South Polar Terrain (SPT) geological province defines a characteristic tectonic style, geometry, and size-scale: It is a crudely circular, kilometer-deep topographic depression that subtends ~70° in arc and is bounded by a circumpolar chain of south-facing arcuate scarps and kilometer- scale mountain belts (Porco et al.2006, Science 311 1393-1401). Nearer its center, ongoing water-ice eruptions emanate from a series of ~200-km-long quasi-parallel rifts, called "tiger stripes" that have an average spacing of 32 km. On the trailing side of Enceladus, the surface locations of ancient, now inactive tectonic provinces similar to the SPT are inferred from the similar geological patterns, geometry, and size- scales of two other tectonically disrupted regions; Sarandib Planitia (4°N, 298°W) and Diyar Planitia (0°N, 240°W).These regions may record the locations of ancient diapirs that have dissipated or perhaps the progressive migration of a single warm diapir to the South Pole of Enceladus as suggested by Nimmo and Pappalardo (2006, Nature 441, 614-616).

  5. The tectonic and volcanic evolution of Venus: Catastrophic or gradual?

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1993-01-01

    Radar imaging and altimetry data from the Magellan mission have yielded important new constraints on the tectonic and volcanic history of Venus and on its internal dynamics. The planet lacks global plate tectonics, but a number of chasm systems and corona moat structures have arcuate planforms, asymmetric topogrpahic profiles, and relief analogous to deep-sea trenches on Earth and may be products of limited lithospheric underthrusting or subduction. Several lines of evidence point to a crust and upper mantle stronger than would be predicted by simple extrapolation from Earth and the 450 K greater surface temperature; these include the unrelaxed depths of impact craters, apparently large values of elastic lithosphere thickness, and large ratios of gravity to topography. The density of impact craters indicates an averate crater retention age of about 500 My, but not more than 5% of the recognized craters have been volcanically embayed. This last observation has led to the proposal that Venus has been subjected to one or more global resurfacing events, the latest about 500 My ago, and that the volcanic flux during intervals between such events has been low. That more recent tectonic activity has been widespread, however, is indicated by the high relief and slopes of mountains, chasm walls, and plateau margins; the significant fraction (0.3) of impact craters deformed by younger faults; and the postformational vertical deformation of long channels. Interior dynamical scenarios advanced to account for episodic volcanic resurfacing include catastrophic overturn of a global lithosphere thickened by cooling or compositional buoyancy and strongly time-dependent mantle convective heat flux. Outgassing considerations and analogy with Earth and other terrestrial planets, however, suggests that such catastrophic models are unlikely. If the mantle of Venus cooled more efficiently than that of Earth because of, say, different boundary conditions, a different flow law, or a

  6. The dynamic evolution of rheumatology in Korea.

    PubMed

    Kim, Ho-Youn; Song, Yeong-Wook

    2016-03-01

    Rheumatology was first recognized as a distinct clinical specialty in Korea just 35 years ago. Young professors who were trained in rheumatology in the USA and afterwards returned to Korea contributed substantially to advances in rheumatology clinical practice, educational programmes and research activities. They also established the Korean Rheumatism Association, later renamed the Korean College of Rheumatology. These young rheumatologists had a major role not only in raising the level of clinical and scientific activities, but also in promoting academic exchanges around the Asia-Pacific region, the USA and Europe. Subsequently, Korea's rapid economic growth and high education level enabled rheumatology to advance rapidly. Today, continued efforts are required to raise the standard of clinical and basic research, to optimize clinical practice with regard to new biologic agents, to exploit personalized and targeted therapies for the rheumatic diseases, and to meet the medical demands of Korea's ageing society.

  7. Molecular epidemiology of norovirus in South Korea.

    PubMed

    Lee, Sung-Geun; Cho, Han-Gil; Paik, Soon-Young

    2015-02-01

    Norovirus is a major cause of viral gastroenteritis and a common cause of foodborne and waterborne outbreaks. Norovirus outbreaks are responsible for economic losses, most notably to the public health and food industry field. Norovirus has characteristics such as low infectious dose, prolonged shedding period, strong stability, great diversity, and frequent genome mutations. Besides these characteristics, they are known for rapid and extensive spread in closed settings such as hospitals, hotels, and schools. Norovirus is well known as a major agent of food-poisoning in diverse settings in South Korea. For these reasons, nationwide surveillance for norovirus is active in both clinical and environmental settings in South Korea. Recent studies have reported the emergence of variants and novel recombinants of norovirus. In this review, we summarized studies on the molecular epidemiology and nationwide surveillance of norovirus in South Korea. This review will provide information for vaccine development and prediction of new emerging variants of norovirus in South Korea.

  8. Antiviral treatment of influenza in South Korea.

    PubMed

    Choe, Young June; Lee, Hyunju; Lee, Hoan Jong; Choi, Eun Hwa

    2015-06-01

    Antiviral therapy has an important role in the treatment and chemoprophylaxis of influenza. At present, two classes of antiviral agents, adamantanes and neuraminidase inhibitors, are available for the treatment and chemoprophylaxis of influenza in Korea. Because of the widespread resistance against adamantanes, neuraminidase inhibitors are mainly used. Because each country has a unique epidemiology of influenza, the proper use of antiviral agents should be determined based on local data. Decisions on the clinical practice in the treatment of influenza in South Korea are guided by the local surveillance data, practice guidelines, health insurance system and the resistance patterns of the circulating influenza viruses. This review highlights the role of antiviral agents in the treatment and outcome of influenza in Korea by providing comprehensive information of their clinical usage in Korea.

  9. Negotiations with North Korea: Lessons learned

    NASA Astrophysics Data System (ADS)

    Gallucci, Robert L.

    2014-05-01

    In this paper, I summarize the events leading to the negotiation of the Agreed Framework with North Korea. I also highlight the threats that result from the current situation, and some of the technical issues relevant to understanding events.

  10. Vulnerability to temperature-related mortality in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Son, Ji-Young; Lee, Jong-Tae; Anderson, G. Brooke; Bell, Michelle L.

    2011-07-01

    Studies indicate that the mortality effects of temperature may vary by population and region, although little is known about the vulnerability of subgroups to these risks in Korea. This study examined the relationship between temperature and cause-specific mortality for Seoul, Korea, for the period 2000-7, including whether some subgroups are particularly vulnerable with respect to sex, age, education and place of death. The authors applied time-series models allowing nonlinear relationships for heat- and cold-related mortality, and generated exposure-response curves. Both high and low ambient temperatures were associated with increased risk for daily mortality. Mortality risk was 10.2% (95% confidence interval 7.43, 13.0%) higher at the 90th percentile of daily mean temperatures (25 °C) compared to the 50th percentile (15 °C). Mortality risk was 12.2% (3.69, 21.3%) comparing the 10th (-1 °C) and 50th percentiles of temperature. Cardiovascular deaths showed a higher risk to cold, whereas respiratory deaths showed a higher risk to heat effect, although the differences were not statistically significant. Susceptible populations were identified such as females, the elderly, those with no education, and deaths occurring outside of a hospital for heat- and cold-related total mortality. Our findings provide supportive evidence of a temperature-mortality relationship in Korea and indicate that some subpopulations are particularly vulnerable.

  11. Serological Detection of Borrelia burgdorferi among Horses in Korea.

    PubMed

    Lee, Seung-Hun; Yun, Sun-Hee; Choi, Eunsang; Park, Yong-Soo; Lee, Sang-Eun; Cho, Gil-Jae; Kwon, Oh-Deog; Kwak, Dongmi

    2016-02-01

    Lyme disease is a tick-borne zoonotic infectious disease caused by Borrelia burgdorferi. The present study assessed the infection status of B. burgdorferi among horses reared in Korea using ELISA and PCR. Between 2009 and 2013, blood samples were collected from 727 horses throughout Korea. Data for each animal including age, gender, breed, and region of sample collection were used for epidemiological analysis. Overall, 38 (5.2%; true prevalence: 5.5%) of 727 horses were seropositive by ELISA. There were statistically significant differences according to breed and region (P<0.001) whose differences might be attributed to the ecology of vector ticks and climate conditions. Using 2 nested PCR, none of the samples tested positive for B. burgdorferi. Thus, a positive ELISA result can indicate only that the tested horse was previously exposed to B. burgdorferi, with no certainty over the time of exposure. Since global warming is likely to increase the abundance of ticks in Korea, continuous monitoring of tick-borne diseases in Korean horses is needed.

  12. Disease prevalence and mortality among agricultural workers in Korea.

    PubMed

    Lee, Won Jin; Cha, Eun Shil; Moon, Eun Kyeong

    2010-12-01

    The aim of this paper was to provide an overview of mortality and disease prevalence related to occupational diseases among agricultural workers in Korea. We evaluated the age-standardized mortality rates and the prevalence of chronic diseases and compared them with those of other populations using death registration data from 2004 through 2008 and the 2005 Korean National Health and Nutrition Examination Survey. In addition, we conducted a literature review on published articles examining the health status of farmers in Korea. Agricultural workers have a significantly higher mortality of cancer, tuberculosis, chronic respiratory diseases, liver diseases, suicide, motor and non-motor vehicle accidents. Compared to other populations, farmers have higher prevalence rates of arthritis and intervertebral disc disorders. The literature review revealed a number of work-related diseases among farmers, such as musculoskeletal diseases, pesticide poisoning, infections, and respiratory and neurologic diseases. Korean farmers demonstrate a distinct pattern of mortality and disease prevalence compared to other populations. Although lifestyle factors remain important contributors to those deaths and diseases, our study suggests that occupation is a major determinant as well. Intensive programs such as surveillance systems, therefore, should be developed in order to identify and prevent work-related diseases among agricultural workers in Korea.

  13. Serological Detection of Borrelia burgdorferi among Horses in Korea

    PubMed Central

    Lee, Seung-Hun; Yun, Sun-Hee; Choi, Eunsang; Park, Yong-Soo; Lee, Sang-Eun; Cho, Gil-Jae; Kwon, Oh-Deog; Kwak, Dongmi

    2016-01-01

    Lyme disease is a tick-borne zoonotic infectious disease caused by Borrelia burgdorferi. The present study assessed the infection status of B. burgdorferi among horses reared in Korea using ELISA and PCR. Between 2009 and 2013, blood samples were collected from 727 horses throughout Korea. Data for each animal including age, gender, breed, and region of sample collection were used for epidemiological analysis. Overall, 38 (5.2%; true prevalence: 5.5%) of 727 horses were seropositive by ELISA. There were statistically significant differences according to breed and region (P<0.001) whose differences might be attributed to the ecology of vector ticks and climate conditions. Using 2 nested PCR, none of the samples tested positive for B. burgdorferi. Thus, a positive ELISA result can indicate only that the tested horse was previously exposed to B. burgdorferi, with no certainty over the time of exposure. Since global warming is likely to increase the abundance of ticks in Korea, continuous monitoring of tick-borne diseases in Korean horses is needed. PMID:26951987

  14. Current status and strategies for viral hepatitis control in Korea.

    PubMed

    Sinn, Dong Hyun; Cho, Eun Ju; Kim, Ji Hoon; Kim, Do Young; Kim, Yoon Jun; Choi, Moon Seok

    2017-09-01

    Viral hepatitis is one of major global health challenges with increasing disease burden worldwide. Hepatitis B virus and hepatitis C virus infections are major causes of chronic liver diseases. They can lead to cirrhosis, hepatocellular carcinoma, and death in significant portion of affected people. Transmission of hepatitis B virus can be blocked by vaccination. Progression of hepatitis B virus-related liver diseases can be prevented by long-term viral suppression with effective drugs. Although vaccine for hepatitis C virus is currently unavailable, hepatitis C virus infection can be eradicated by oral direct antiviral agents. To eliminate viral hepatitis, World Health Organization (WHO) has urged countries to develop national goals and targets through reducing 90% of new infections and providing universal access to key treatment services up to 80%. This can lead to 65% reduction of viral hepatitis-related mortality. Here, we discuss some key features of viral hepatitis, strategies to control viral hepatitis suggested by WHO, and current status and strategies for viral hepatitis control in South Korea. To achieve the goal of viral hepatitis elimination by 2030 in South Korea, an independent 'viral hepatitis sector' in Centers for Disease Control & Prevention (CDC) needs to be established to organize and execute comprehensive strategy for the management of viral hepatitis in South Korea.

  15. Geographic Distribution of Urologists in Korea, 2007 to 2012.

    PubMed

    Song, Yun Seob; Shim, Sung Ryul; Jung, Insoo; Sun, Hwa Yeon; Song, Soo Hyun; Kwon, Soon-Sun; Ko, Young Myoung; Kim, Jae Heon

    2015-11-01

    The adequacy of the urologist work force in Korea has never been investigated. This study investigated the geographic distribution of urologists in Korea. County level data from the National Health Insurance Service and National Statistical Office was analyzed in this ecological study. Urologist density was defined by the number of urologists per 100,000 individuals. National patterns of urologist density were mapped graphically at the county level using GIS software. To control the time sequence, regression analysis with fitted line plot was conducted. The difference of distribution of urologist density was analyzed by ANCOVA. Urologists density showed an uneven distribution according to county characteristics (metropolitan cities vs. nonmetropolitan cities vs. rural areas; mean square=102.329, P<0.001) and also according to year (mean square=9.747, P=0.048). Regression analysis between metropolitan and non-metropolitan cities showed significant difference in the change of urologists per year (P=0.019). Metropolitan cities vs. rural areas and non-metropolitan cities vs. rural areas showed no differences. Among the factors, the presence of training hospitals was the affecting factor for the uneven distribution of urologist density (P<0.001). Uneven distribution of urologists in Korea likely originated from the relatively low urologist density in rural areas. However, considering the time sequencing data from 2007 to 2012, there was a difference between the increase of urologist density in metropolitan and non-metropolitan cities.

  16. Temporal Trends of Hospitalized Patients with Heart Failure in Korea

    PubMed Central

    Youn, Jong-Chan; Ryu, Kyu-Hyung

    2017-01-01

    Heart failure (HF) is an important cardiovascular disease because of its increasing prevalence, significant morbidity, high mortality and rapidly expanding health care costs. The number of HF patients is increasing worldwide and Korea is no exception. Temporal trends of four representative Korean hospitalized HF registries–the Hallym HF study, the Korean Multicenter HF study, the Korean Heart Failure (KorHF) registry and the Korean Acute Heart Failure (KorAHF) registry showed mild survival improvement reflecting overall HF patient care development in Korea despite the increased severity of enrolled patients with higher incidence of multiple comorbidities. Moreover, device therapies such as implantable cardioverter defibrillator and cardiac resynchronization therapy and definitive treatment such as heart transplantation have been increasing in Korea as well. To prevent HF burden increase, it is essential to set up long term effective prevention strategies for better control of ischemic heart disease, hypertension and diabetes, which might be risk factors for HF development. Moreover, proper HF guidelines, performance measures, and performance improvement programs might be necessary to limit HF burden as well. PMID:28154584

  17. Factors influencing computer literacy of Taiwan and South Korea nurses.

    PubMed

    Hsu, Hui-Mei; Hou, Ying-Hui; Chang, I-Chiu; Yen, David C

    2009-04-01

    Healthcare is experiencing a major transformation in its information technology base. Hospitals are adopting information technology (IT) to reduce costs and increase competitiveness. IT applications in healthcare are trending towards electronic patient records and even health records. Therefore, practices in nursing are also affected by IT. Many researchers have studied what computer literacy a nurse should possess, but have focused less on factors that actually impact computer literacy. The purposes of this study are to examine current computer literacy levels of nurses, and to indicate what variables influence their computer literacy. Taiwan and South Korea both implemented a national health insurance system, and used state-of-the art IT to provide higher volume and better quality of services. The data were collected from two case hospitals which are located in Taiwan and South Korea, respectively. By using a structured questionnaire, a total of 203 nurses responded; 104 from Taiwan and 99 from South Korea. The results revealed that personal innovativeness in IT, computer education, and age are significant factors that affected computer literacy levels. These factors serve as reference for administrators and executives in hospitals, or nursing educators seeking the data necessary to make decisions on curriculum.

  18. Hearing Aid Use and Associated Factors in South Korea

    PubMed Central

    Moon, Il Joon; Baek, Sun Young; Cho, Yang-Sun

    2015-01-01

    Abstract Despite the high prevalence of hearing impairment in the elderly, the rate of hearing aid use is still low. The objectives of this study were to report the nation-wide prevalence of hearing aid use in the Korean population and to determine the associated factors with hearing aid use utilizing a nationally representative data set. We obtained data from the 2010 to 2012 Korea National Health and Nutrition Examination Surveys, which were cross-sectional surveys of the civilian, noninstitutionalized population of the Republic of Korea at age ≥40 years (N = 12,709). A field survey team performed interviews as well as physical examinations. Hearing aid use was assessed using an interviewer-administered questionnaire and pure-tone audiometry was administered for all participants in a sound-attenuating booth. Prevalence of hearing aid acquisition and regular use were calculated in participants who reported perceived hearing loss and who have bilateral hearing thresholds exceeding the 40 dB hearing level. Multivariable analyses were used to examine the associated factors with hearing aid use. The prevalence of hearing aid acquisition and regular use was 17.4% and 12.6%, respectively, in South Korea. Increased hearing threshold (OR 1.05, 95% CI 1.03–1.07), severe perceived hearing loss (OR 10.73, 95% CI 4.52–25.46), annoying tinnitus (OR 3.30, 95% CI 1.61–6.74), balance problems (OR 0.39, 95% CI 0.18–0.86), and myopia (OR 0.30, 95% CI 0.12–0.76) were associated factors of regular use of hearing aids. The prevalence of hearing aid use in Korea is relatively low. Finding relevant factors of hearing aid use could provide further insight in setting up hearing-rehabilitation strategy for the elderly with significant hearing loss. PMID:26496259

  19. Hearing Aid Use and Associated Factors in South Korea.

    PubMed

    Moon, Il Joon; Baek, Sun Young; Cho, Yang-Sun

    2015-10-01

    Despite the high prevalence of hearing impairment in the elderly, the rate of hearing aid use is still low. The objectives of this study were to report the nation-wide prevalence of hearing aid use in the Korean population and to determine the associated factors with hearing aid use utilizing a nationally representative data set.We obtained data from the 2010 to 2012 Korea National Health and Nutrition Examination Surveys, which were cross-sectional surveys of the civilian, noninstitutionalized population of the Republic of Korea at age ≥40 years (N = 12,709). A field survey team performed interviews as well as physical examinations. Hearing aid use was assessed using an interviewer-administered questionnaire and pure-tone audiometry was administered for all participants in a sound-attenuating booth. Prevalence of hearing aid acquisition and regular use were calculated in participants who reported perceived hearing loss and who have bilateral hearing thresholds exceeding the 40 dB hearing level. Multivariable analyses were used to examine the associated factors with hearing aid use.The prevalence of hearing aid acquisition and regular use was 17.4% and 12.6%, respectively, in South Korea. Increased hearing threshold (OR 1.05, 95% CI 1.03-1.07), severe perceived hearing loss (OR 10.73, 95% CI 4.52-25.46), annoying tinnitus (OR 3.30, 95% CI 1.61-6.74), balance problems (OR 0.39, 95% CI 0.18-0.86), and myopia (OR 0.30, 95% CI 0.12-0.76) were associated factors of regular use of hearing aids.The prevalence of hearing aid use in Korea is relatively low. Finding relevant factors of hearing aid use could provide further insight in setting up hearing-rehabilitation strategy for the elderly with significant hearing loss.

  20. Prevalence and incidence of rheumatoid arthritis in South Korea.

    PubMed

    Sung, Yoon-Kyoung; Cho, Soo-Kyung; Choi, Chan-Bum; Bae, Sang-Cheol

    2013-06-01

    Several studies of rheumatoid arthritis (RA) incidence and prevalence indicate that occurrence of the disease varies significantly among different populations. We aimed to estimate the prevalence and incidence of RA in South Korea. We used Korean National Health Insurance (NHI) claims data to estimate the prevalence of RA in 2007-2009 and the incidence of RA in 2008. On the basis of our previous validation study, the presence of RA was defined by the diagnostic code for RA with biologic or non-biologic disease-modifying anti-rheumatic drugs in the same claim in each year. To estimate the incidence of RA, we identified cases of RA in 2008 and set the 12-month period prior to 2008 as a disease-free period. Among the incident case of 2008, only patients who continued treatment in 2009 were defined as true incident case of RA in 2008. The corresponding prevalence estimates were 0.26 % (95 % CI 0.25-0.27) in 2006, 0.27 % (95 % CI 0.26-0.28) in 2007, and 0.27 % (95 % CI 0.26-0.28) in 2008. The incidence of RA in 2008 was estimated at 42/100,000 (95 % CI 29.3-54.7) in the general population of South Korea. Data gathered nationwide through the NHI yielded estimates of RA prevalence and incidence in South Korea. This study is the first report of nationwide prevalence and incidence of South Korea and those are comparable to values for other countries in Asia.

  1. Factor affecting happiness among nursing students in South Korea.

    PubMed

    Jun, W H; Jo, M J

    2016-08-01

    WHAT IS KNOWN ON THE SUBJECT?: Despite the increased interest in nursing students' happiness in South Korea, few studies have attempted to identify factors influencing their happiness. Therefore, nursing educators should consistently investigate the factors influencing happiness and develop strategies to improve happiness among Korean nursing students. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: This study confirmed that there were positive correlations between grateful disposition, social support and happiness. In addition, grateful disposition and support from intimate people were identified as predictors of happiness in Korean nursing students. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Development of intervention programmes to help nursing students increase grateful disposition and support from intimate people may be helpful for improving happiness. These programmes can include activity, such as writing a gratitude journal, and extracurricular programmes, such as mentoring programmes between seniors and juniors and/or professor and student. Introduction Happiness is very important in the training and development of nursing students as future nurses. However, nursing students experience a high level of stress and low level of happiness in South Korea. Aim This study aimed to investigate factors that affect happiness among nursing students in South Korea. Method Data were collected from a total of 241 nursing enrolled in two 4-year baccalaureate nursing programmes in South Korea, using a self-administrated questionnaire. To identify predictors of happiness, stepwise regression analysis was conducted. Results The results indicated that grateful disposition and support from intimate people significantly predict happiness among Korean nursing students. These two factors accounted for 38.0% of the variance in happiness. Discussion This study indicated grateful disposition and support from intimate people as factors promoting happiness in nursing students. The findings

  2. An overview of biotechnology in Korea.

    PubMed

    Choi; Hahm; Rhee; Han

    1999-03-01

    During the 1980s and 1990s, Korea has invested heavily in biotechnology research and development, with the aim of becoming a leading nation in this field. It is important to understand the historical progress of this development in order to appreciate the current state of biotechology in Korea. However, it is equally important to know what research is currently being planned and carried out, and by whom.

  3. US Military Presence in a Unified Korea

    DTIC Science & Technology

    2003-04-07

    profiles/ap_mp_05.cfm ; Internet; accessed 11 March 2003; and World Almanac Education Group, Inc., The World Almanac and Book of Facts 2003 (New York...New York: World Almanac Books, 2003), 108, 771, 799, 801, 843. 15 Han Woo-Keun, The History of Korea (Seoul, Korea: The Eul-Yoo Publishing Company...January 2003. 37 World Almanac Education Group, Inc., The World Almanac and Book of Facts 2003 (New York, New York: World Almanac Books, 2003), 218. 38

  4. U.S.-South Korea Relations

    DTIC Science & Technology

    2014-02-12

    South Korea and “normalize” the tours of U.S. troops there, including longer stays with family members accompanying them. In May 2011, Senators Carl ...Kim Dae- jung , who in the second attempt was saved only by U.S. intervention. The divisions that opened under Park continue to be felt today...have deepened in South Korea. In 1997, long- time dissident Kim Dae- jung was elected to the presidency, the first time an opposition party had

  5. North Korea: War drums or peace pipes?

    SciTech Connect

    Keeny, S.M. Jr.

    1994-07-01

    President Clinton has wisely seized the opportunity, presented by former President Jimmy Carter`s meeting with North Korea leader Kim Il Sung, for renewed negotiations with Pyongyang on its nuclear program. While a successful outcome cannot be guaranteed, both sides have backed off the mounting confrontation that threatened to lead to either the emergence of a nuclear North Korea or a second Korean war.

  6. Publication of the Korea-WHO Cooperation History — 70 Years of Working Together for Heath: World Health Organization and the Republic of Korea

    PubMed Central

    2017-01-01

    The World Health Organization (WHO) have been in collaborative efforts with the Republic of Korea in keeping of and for better health for all for the past decades. From the control of parasites to building of community health system in rural places, the works has now resulted in healthier Korea than ever, and has transformed the role of engaging as the world leader in contribution of health and development. Seventy years of independence, war, and poverty, transforming from a recipient country of official development assistance to a significant donor to the global society, we have emphasized the importance of international cooperation and the role of WHO in the past years in Korea and neighboring countries. Looking back of the past is meaningful to diagnose the present problems, and to foresee the future of our world. PMID:28145638

  7. Publication of the Korea-WHO Cooperation History - 70 Years of Working Together for Heath: World Health Organization and the Republic of Korea.

    PubMed

    Cho, Heeyeon; Lee, Dong Woo; Choe, Young June; Choe, Seung Ah; Park, No Yai

    2017-03-01

    The World Health Organization (WHO) have been in collaborative efforts with the Republic of Korea in keeping of and for better health for all for the past decades. From the control of parasites to building of community health system in rural places, the works has now resulted in healthier Korea than ever, and has transformed the role of engaging as the world leader in contribution of health and development. Seventy years of independence, war, and poverty, transforming from a recipient country of official development assistance to a significant donor to the global society, we have emphasized the importance of international cooperation and the role of WHO in the past years in Korea and neighboring countries. Looking back of the past is meaningful to diagnose the present problems, and to foresee the future of our world.

  8. The tectonics of Venus: An overview

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1992-01-01

    While the Pioneer Venus altimeter, Earth-based radar observatories, and the Venera 15-16 orbital imaging radars provided views of large-scale tectonic features on Venus at ever-increasing resolution, the radar images from Magellan constitute an improvement in resolution of at least an order of magnitude over the best previously available. A summary of early Magellan observations of tectonic features on Venus was published, but data available at that time were restricted to the first month of mapping and represented only about 15 percent of the surface of the planet. Magellan images and altimetry are now available for more than 95 percent of the Venus surface. Thus a more global perspective may be taken on the styles and distribution of lithospheric deformation on Venus and their implications for the tectonic history of the planet.

  9. Plate tectonic modelling: virtual reality with GMAP

    NASA Astrophysics Data System (ADS)

    Torsvik, Trond Helge; Smethurst, Mark Andrew

    1999-05-01

    Palaeogeographic reconstructions have been an integral part of global tectonic research since the advent of the plate tectonic paradigm, and GMAP is a state of the art computer program which performs all processing and plotting tasks associated with the generation of palaeogeographic reconstructions and plate tectonic modelling. GMAP is menu-driven and easy to use; the user is never far removed from the basic data from which palaeogeographic reconstructions are derived, and therefore has a sense of total control over the program's performance. GMAP can generate reconstructions based on known Euler rotation data poles or palaeomagnetic poles. The user is also free simply to move continents around on the screen, according to less tangible constraints. GMAP is supplied with a full range of continental outlines. It is also possible to import new continents via simple ASCII files. GMAP is in use at leading institutions world-wide, and has been the work-horse of the EUROPEAN GEOTRAVERSE and EUROPROBE projects.

  10. Tectonics of Neyterkob corona on Venus

    NASA Technical Reports Server (NTRS)

    Kauhanen, K.

    1993-01-01

    Neyterkob double corona (50 deg N 202 deg) presents an area of corona-related interfering tectonic patterns which are formed in different phases of evolution of the corona and modified by regional stresses. Analyzing the patterns can reveal something about the coronal formation. Tectonic features form distinct units on topographic depressions, slopes, and volcanic flows extending over one radius of the corona. A remarkable amount of compressional features were found near the rim and related to interaction between adjacent coronae. Radial extension was mainly observed on a peculiar NE-SW trending high crossing the corona. Concentric fractures were found to the east partly connected to the lithospheric flexure. Tectonic features indicate movements of volcanic activity and modification of the area by more regional stresses.

  11. Subduction Drive of Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Hamilton, W. B.

    2003-12-01

    Don Anderson emphasizes that plate tectonics is self-organizing and is driven by subduction, which rights the density inversion generated as oceanic lithosphere forms by cooling of asthenosphere from the top. The following synthesis owes much to many discussions with him. Hinge rollback is the key to kinematics, and, like the rest of actual plate behavior, is incompatible with bottom-up convection drive. Subduction hinges (which are under, not in front of, thin leading parts of arcs and overriding plates) roll back into subducting plates. The Pacific shrinks because bounding hinges roll back into it. Colliding arcs, increasing arc curvatures, back-arc spreading, and advance of small arcs into large plates also require rollback. Forearcs of overriding plates commonly bear basins which preclude shortening of thin plate fronts throughout periods recorded by basin strata (100 Ma for Cretaceous and Paleogene California). This requires subequal rates of advance and rollback, and control of both by subduction. Convergence rate is equal to rates of rollback and advance in many systems but is greater in others. Plate-related circulation probably is closed above 650 km. Despite the popularity of concepts of plumes from, and subduction into, lower mantle, there is no convincing evidence for, and much evidence against, penetration of the 650 in either direction. That barrier not only has a crossing-inhibiting negative Clapeyron slope but also is a compositional boundary between fractionated (not "primitive"), sluggish lower mantle and fertile, mobile upper mantle. Slabs sink more steeply than they dip. Slabs older than about 60 Ma when their subduction began sink to, and lie down on and depress, the 650-km discontinuity, and are overpassed, whereas younger slabs become neutrally buoyant in mid-upper mantle, into which they are mixed as they too are overpassed. Broadside-sinking old slabs push all upper mantle, from base of oceanic lithosphere down to the 650, back under

  12. Reducing risk where tectonic plates collide

    USGS Publications Warehouse

    Gomberg, Joan S.; Ludwig, Kristin A.

    2017-06-19

    Most of the world’s earthquakes, tsunamis, landslides, and volcanic eruptions are caused by the continuous motions of the many tectonic plates that make up the Earth’s outer shell. The most powerful of these natural hazards occur in subduction zones, where two plates collide and one is thrust beneath another. The U.S. Geological Survey’s (USGS) “Reducing Risk Where Tectonic Plates Collide—A USGS Plan to Advance Subduction Zone Science” is a blueprint for building the crucial scientific foundation needed to inform the policies and practices that can make our Nation more resilient to subduction zone-related hazards.

  13. Convective, intrusive geothermal plays: what about tectonics?

    NASA Astrophysics Data System (ADS)

    Santilano, A.; Manzella, A.; Gianelli, G.; Donato, A.; Gola, G.; Nardini, I.; Trumpy, E.; Botteghi, S.

    2015-09-01

    We revised the concept of convective, intrusive geothermal plays, considering that the tectonic setting is not, in our opinion, a discriminant parameter suitable for a classification. We analysed and compared four case studies: (i) Larderello (Italy), (ii) Mt Amiata (Italy), (iii) The Geysers (USA) and (iv) Kizildere (Turkey). The tectonic settings of these geothermal systems are different and a matter of debate, so it is hard to use this parameter, and the results of classification are ambiguous. We suggest a classification based on the age and nature of the heat source and the related hydrothermal circulation. Finally we propose to distinguish the convective geothermal plays as volcanic, young intrusive and amagmatic.

  14. Tectonic evolution of the Qinghai-Tibet Plateau

    NASA Astrophysics Data System (ADS)

    Pan, Guitang; Wang, Liquan; Li, Rongshe; Yuan, Sihua; Ji, Wenhua; Yin, Fuguang; Zhang, Wanping; Wang, Baodi

    2012-07-01

    The Qinghai-Tibet Plateau, composed of several continental slivers within the eastern Tethyan domain, is one of the pivotal sites to examine to better understand the theory of plate tectonics and the orogenic evolution on Earth. This plateau is generally inferred to be a collage of several continental blocks that rifted from Gondwanaland and subsequently accreted to the Asian continent. However, recent recognition of over twenty ophiolite mélange zones and their associated island arcs indicates that the traditional model of tectonic evolution requires revision. Based on 177 recently finished 1:250,000 scale geological maps and related studies, we summarize the main tectonic context of the Qinghai-Tibet Plateau and propose a new integrated model to account for the new findings. The complex orogen of the immense Qinghai-Tibet Plateau, consisting of multiple island arc-basin systems that developed at different stages while surrounded by the North China, Yangtze, Tarim, and Indian plates, is emphasized. The entire orogen, surrounded by suture zones that mark the locations of oceanic closure, is investigated by examining (I) the first-order tectonic units and ophiolitic mélanges (including arc-arc/continent collision zones) and (II) their internally enclosed blocks as the second-order tectonic units. Therefore, the Qinghai-Tibet Plateau is divided into three major orogenic systems, namely, from northeast to southwest, the Early Paleozoic Qinling-Qilianshan-Kunlunshan (Qin-Qi-Kun), the Late Paleozoic-Triassic Qiangtang-Sanjiang, and the Late Paleozoic to Cenozoic Gangdese-Himalaya orogenic systems, which are separated by the Kangxiwa-Muzitagh-Maqin-Mianxian and the Bangong-Shuanghu-Changning-Menglian sutures, respectively. We propose that the formation and evolution of the Qinghai-Tibet Plateau to have been intrinsically related to those of the eastern Tethys, recorded by the Longmu Co-Shuanghu ophiolite mélange zone, the Southern Qiangtang Paleozoic accretionary arc

  15. A Comparison between Deep and Shallow Stress Fields in Korea Using Earthquake Focal Mechanism Inversions and Hydraulic Fracturing Stress Measurements

    NASA Astrophysics Data System (ADS)

    Lee, Rayeon; Chang, Chandong; Hong, Tae-kyung; Lee, Junhyung; Bae, Seong-Ho; Park, Eui-Seob; Park, Chan

    2016-04-01

    We are characterizing stress fields in Korea using two types of stress data: earthquake focal mechanism inversions (FMF) and hydraulic fracturing stress measurements (HF). The earthquake focal mechanism inversion data represent stress conditions at 2-20 km depths, whereas the hydraulic fracturing stress measurements, mostly conducted for geotechnical purposes, have been carried out at depths shallower than 1 km. We classified individual stress data based on the World Stress Map quality ranking scheme. A total of 20 FMF data were classified into A-B quality, possibly representing tectonic stress fields. A total of 83 HF data out of compiled 226 data were classified into B-C quality, which we use for shallow stress field characterization. The tectonic stress, revealed from the FMF data, is characterized by a remarkable consistency in its maximum stress (σ1) directions in and around Korea (N79±2° E), indicating a quite uniform deep stress field throughout. On the other hand, the shallow stress field, represented by HF data, exhibits local variations in σ1 directions, possibly due to effects of topography and geologic structures such as faults. Nonetheless, there is a general similarity in σ1 directions between deep and shallow stress fields. To investigate the shallow stress field statistically, we follow 'the mean orientation and wavelength analysis' suggested by Reiter et al. (2014). After the stress pattern analysis, the resulting stress points distribute sporadically over the country, not covering the entire region evenly. In the western part of Korea, the shallow σ1directions are generally uniform with their search radius reaching 100 km, where the average stress direction agrees well with those of the deep tectonic stress. We note two noticeable differences between shallow and deep stresses in the eastern part of Korea. First, the shallow σ1 orientations are markedly non-uniform in the southeastern part of Korea with their search radius less than 25 km

  16. Tectonic reconstructions for paleobathymetry in Drake Passage

    NASA Astrophysics Data System (ADS)

    Eagles, Graeme; Jokat, Wilfried

    2014-01-01

    A minimum-complexity tectonic reconstruction, based on published and new basin opening models, depicts how the Scotia Sea grew by Cenozoic plate divergence, dismembering a Jurassic sheared margin of Gondwana. Part of the Jurassic-early Cretaceous ocean that accreted to this margin forms the core of the Central Scotia Plate, the arc plate above a trench at the eastern end of the Scotia Sea, which migrated east away from the Antarctic and South American plates. A sequence of extensional basins opened on the western edge of the Central Scotia Plate at 50-30 Ma, decoupled from the South American Plate to the northwest by slow motion on a long transform fault. Succeeding the basins, seafloor spreading started around 30 Ma on the West Scotia Ridge, which propagated northwards in the 23-17 Ma period and ceased to operate at 6 Ma. The circuits of plate motions inside and outside the Scotia Arc are joined via rotations that describe Antarctic-Central Scotia plate motion in Powell Basin until 20 Ma, and along the South Scotia Ridge thereafter. The modelled relative motion at the northern edge of the Scotia Sea is thus constrained only by the plate circuit, but nonetheless resembles that known coarsely from the geological record of Tierra del Fuego. A paleobathymetric interpretation of nine time slices in the model shows Drake Passage developing as an intermediate-depth oceanographic gateway at 50-30 Ma, with deep flow possible afterwards. Initially, this deep flow would have been made tortuous by numerous intermediate and shallow barriers. A frontal pattern resembling that in the modern Scotia Sea would have awaited the clearance of significant barriers by continuing seafloor spreading in the Scotia Sea at ~ 18.5 Ma, at Shag Rocks Passage, and after 10 Ma southeast of South Georgia.

  17. Modeling orbital changes on tectonic time scales

    NASA Technical Reports Server (NTRS)

    Crowley, Thomas J.

    1992-01-01

    Geologic time series indicate significant 100 ka and 400 ka pre-Pleistocene climate fluctuations, prior to the time of such fluctuations in Pleistocene ice sheets. The origin of these fluctuations must therefore depend on phenomena other than the ice sheets. In a previous set of experiments, we tested the sensitivity of an energy balance model to orbital insolation forcing, specifically focusing on the filtering effect of the Earth's geography. We found that in equatorial areas, the twice-yearly passage of the sun across the equator interacts with the precession index to generate 100 ka and 400 ka power in our modeled time series. The effect is proportional to the magnitude of land in equatorial regions. We suggest that such changes may reflect monsoonal variations in the real climate system, and the subsequent wind and weathering changes may transfer some of this signal to the marine record. A comparison with observed fluctuations of Triassic lake levels is quite favorable. A number of problems remain to be studied or clarified: (1) the EBM experiments need to be followed up by a limited number of GCM experiments; (2) the sensitivity to secular changes in orbital forcing needs to be examined; (3) the possible modifying role of sedimentary processes on geologic time series warrants considerably more study; (4) the effect of tectonic changes on Earth's rotation rate needs to be studied; and (5) astronomers need to make explicit which of their predictions are robust and geologists and astronomers have to agree on which of the predictions are most testable in the geologic record.

  18. Global Search of Triggered Tectonic Tremor

    NASA Astrophysics Data System (ADS)

    Peng, Z.; Aiken, C.; Chao, K.; Gonzalez-Huizar, H.; Wang, B.; Ojha, L.; Yang, H.

    2013-05-01

    Deep tectonic tremor has been observed at major plate-boundary faults around the Pacific Rim. While regular or ambient tremor occurs spontaneously or accompanies slow-slip events, tremor could be also triggered by large distant earthquakes and solid earth tides. Because triggered tremor occurs on the same fault patches as ambient tremor and is relatively easy to identify, a systematic global search of triggered tremor could help to identify the physical mechanisms and necessary conditions for tremor generation. Here we conduct a global search of tremor triggered by large teleseismic earthquakes. We mainly focus on major faults with significant strain accumulations where no tremor has been reported before. These includes subduction zones in Central and South America, strike-slip faults around the Caribbean plate, the Queen Charlotte-Fairweather fault system and the Denali fault in the western Canada and Alaska, the Sumatra-Java subduction zone, the Himalaya frontal thrust faults, as well as major strike-slip faults around Tibet. In each region, we first compute the predicted dynamic stresses σd from global earthquakes with magnitude>=5.0 in the past 20 years, and select events with σd > 1 kPa. Next, we download seismic data recorded by stations from local or global seismic networks, and identify triggered tremor as a high-frequency non-impulsive signal that is in phase with the large-amplitude teleseismic waves. In cases where station distributions are dense enough, we also locate tremor based on the standard envelope cross-correlation techniques. Finally, we calculate the triggering potential for the Love and Rayleigh waves with the local fault orientation and surface-wave incident angles. So far we have found several new places that are capable of generating triggered tremor. We will summarize these observations and discuss their implications on physical mechanisms of tremor and remote triggering.

  19. Modeling orbital changes on tectonic time scales

    NASA Technical Reports Server (NTRS)

    Crowley, Thomas J.

    1992-01-01

    Geologic time series indicate significant 100 ka and 400 ka pre-Pleistocene climate fluctuations, prior to the time of such fluctuations in Pleistocene ice sheets. The origin of these fluctuations must therefore depend on phenomena other than the ice sheets. In a previous set of experiments, we tested the sensitivity of an energy balance model to orbital insolation forcing, specifically focusing on the filtering effect of the Earth's geography. We found that in equatorial areas, the twice-yearly passage of the sun across the equator interacts with the precession index to generate 100 ka and 400 ka power in our modeled time series. The effect is proportional to the magnitude of land in equatorial regions. We suggest that such changes may reflect monsoonal variations in the real climate system, and the subsequent wind and weathering changes may transfer some of this signal to the marine record. A comparison with observed fluctuations of Triassic lake levels is quite favorable. A number of problems remain to be studied or clarified: (1) the EBM experiments need to be followed up by a limited number of GCM experiments; (2) the sensitivity to secular changes in orbital forcing needs to be examined; (3) the possible modifying role of sedimentary processes on geologic time series warrants considerably more study; (4) the effect of tectonic changes on Earth's rotation rate needs to be studied; and (5) astronomers need to make explicit which of their predictions are robust and geologists and astronomers have to agree on which of the predictions are most testable in the geologic record.

  20. Preliminary publications book 2 from project on mineral resources, metallogenesis, and tectonics of northeast Asia

    USGS Publications Warehouse

    Nokleberg, Warren J.; Miller, Robert J.; Naumova, Vera V.; Khanchuk, Alexander I.; Parfenov, Leonid M.; Kuzmin, Mikhail I.; Bounaeva, Tatiana M.; Obolenskiy, Alexander A.; Rodionov, Sergey M.; Seminskiy, Zhan V.; Diggles, Michael F.

    2003-01-01

    This is the Web version of a CD-ROM publication. This report consists of summary major compilations and syntheses accomplished in the six-year project through April 2003 for the study on the Mineral Resources, Metallogenesis, and Tectonics of Northeast Asia (Eastern and Southern Siberia, Mongolia, Northeastern China, South Korea, and Japan). The major scientific goals and benefits of the project are to: (1) provide a comprehensive international data base on the mineral resources of the region that is the first, extensive knowledge available in English; (2) provide major new interpretations of the origin and crustal evolution of mineralizing systems and their host rocks, thereby enabling enhanced, broad-scale tectonic reconstructions and interpretations; and (3) promote trade and scientific and technical exchanges between the North America and Northeast Asia. Data from the project are providing sound scientific data and interpretations for commercial firms, governmental agencies, universities, and individuals that are developing new ventures and studies in the project area, and for land-use planning studies that deal with both mineral potential issues. Northeast Asia has vast potential for known and undiscovered mineral deposits; however, little information existed in English in the West until publication of products from this project. Consequently, data and interpretations from the project are providing basic knowledge for major scientific, commercial, national, and international endeavors by other interested individuals and groups.

  1. Population-attributable causes of cancer in Korea: obesity and physical inactivity.

    PubMed

    Park, Sohee; Kim, Yeonju; Shin, Hai-Rim; Lee, Boram; Shin, Aesun; Jung, Kyu-Won; Jee, Sun Ha; Kim, Dong Hyun; Yun, Young Ho; Park, Sue Kyung; Boniol, Mathieu; Boffetta, Paolo

    2014-01-01

    Changes in lifestyle including obesity epidemic and reduced physical activity influenced greatly to increase the cancer burden in Korea. The purpose of the current study was to perform a systematic assessment of cancers attributable to obesity and physical inactivity in Korea. Gender- and cancer site-specific population-attributable fractions (PAF) were estimated using the prevalence of overweight and obesity in 1992-1995 from a large-scale prospective cohort study, the prevalence of low physical activity in 1989 from a Korean National Health Examination Survey, and pooled relative risk estimates from Korean epidemiological studies. The overall PAF was then estimated using 2009 national cancer incidence data from the Korea Central Cancer Registry. Excess body weight was responsible for 1,444 (1.5%) and 2,004 (2.2%) cancer cases among men and women, respectively, in 2009 in Korea. Among men, 6.8% of colorectal, 2.9% of pancreatic, and 16.0% of kidney cancer was attributable to excess body weight. In women, 6.6% of colorectal, 3.9% of pancreatic, 18.7% of kidney, 8.2% of postmenopausal breast, and 32.7% of endometrial cancer was attributable to excess body weight. Low leisure-time physical activity accounted for 8.8% of breast cancer, whereas the PAF for overall cancer was low (0.1% in men, 1.4% in women). Projections suggest that cancers attributable to obesity will increase by 40% in men and 16% in women by 2020. With a significantly increasing overweight and physically inactive population, and increasing incidence of breast and colorectal cancers, Korea faces a large cancer burden attributable to these risk factors. Had the obese population of Korea remained stable, a large portion of obesity-related cancers could have been avoided. Efficient cancer prevention programs that aim to reduce obesity- and physical inactivity-related health problems are essential in Korea.

  2. [Epidemiological characteristics of Middle East Respiratory Syndrome outbreak in the Republic of Korea, 2015].

    PubMed

    Xiang, Nijuan; Lin, Dan; An, Guangxu; Sui, Haitian; Yang, Zhiyong; Li, Dan; Zhao, Jian; Ma, Tao; Wang, Yali; Ren, Ruiqi; Zhang, Xinyan; Ni, Daxin; Zhang, Yanping; Li, Qun

    2015-08-01

    To analyze the epidemiological characteristics of Middle East Respiratory Syndrome (MERS) outbreak in the Republic of Korea in 2015 and provide related information for the public health professionals in China. The incidence data of MERS were collected from the websites of the Korean government, WHO and authoritative media in Korea for this epidemiological analysis. Between May 20 and July 13, 2015, a total of 186 confirmed MERS cases (1 index case, 29 secondary cases, 125 third generation cases, 25 fourth generation cases and 6 cases without clear generation data), including 36 deaths (case fatality rate: 19%), were reported in Korea. All cases were associated with nosocomial transmission except the index case and two possible family infections. Sixteen hospitals in 11 districts in 5 provinces/municipalities in Korea reported confirmed MERS cases, involving 39 medical professionals or staff. For the confirmed cases and death cases, the median ages were 55 years and 70 years respectively, and the cases and deaths in males accounted for 60% and 67% respectively. Up to 78% of the deaths were with underlying medical conditions. Besides the index case, other 12 patients were reported to cause secondary cases, in which 1 caused 84 infections. One imported MERS case from Korea was confirmed in China on May 29, no secondary cases occurred. The viruses strains isolated from the cases in Korea and the imported case in China show no significant variation compared with the strains isolated in the Middle East. The epidemiological pattern of the MERS outbreak in Korea was similar to MERS outbreaks occurred in the Middle East.

  3. House Dust Mite Allergy in Korea: The Most Important Inhalant Allergen in Current and Future

    PubMed Central

    Jeong, Kyoung Yong; Park, Jung-Won

    2012-01-01

    The house-dust mite (HDM), commonly found in human dwellings, is an important source of inhalant and contact allergens. In this report, the importance of HDM allergy in Korea and the characteristics of allergens from dust mite are reviewed with an emphasis on investigations performed in Korea. In Korea, Dermatophagoides farinae is the dominant species of HDM, followed by D. pteronyssinus. Tyrophagus putrescentiae is also found in Korea, but its role in respiratory allergic disease in Korea is controversial. The relatively low densities of mite populations and concentrations of mite major allergens in dust samples from Korean homes, compared to westernized countries, are thought to reflect not only different climatic conditions, but also cultural differences, such as the use of 'ondol' under-floor heating systems in Korean houses. HDM are found in more than 90% of Korean houses, and the level of exposure to HDM is clinically significant. About 40%-60% of Korean patients suffering from respiratory allergies, and more than 40% of patients suffering from atopic dermatitis, are sensitized to HDM. Mite allergens can be summarized according to their inherent auto-adjuvant activities and/or their binding affinities to the adjuvant-like substances: proteolytic enzymes, lipid binding proteins, chitin binding proteins, and allergens not associated with adjuvant-like activity. In general, allergens with a strong adjuvant-like activity or adjuvant-binding activity elicit potent IgE reactivity. In Korea, Der f 2 is the most potent allergen, followed by Der f 1. Immune responses are modulated by the properties of the allergen itself and by the adjuvant-like substances that are concomitantly administered with the antigens. Characterization of allergenic molecules and elucidation of mechanisms by which adjuvant-like molecules modulate allergic reactions, not only in Korea but also worldwide, will provide valuable information on allergic diseases, and are necessary for the

  4. Perceptions of Prophylactic Mastectomy in Korea

    PubMed Central

    Yoon, Han Young; Lee, Jong Won

    2016-01-01

    Background Increasingly, prophylactic mastectomy has been evaluated as a treatment of breast cancer. Hereditary breast cancer now accounts for approximately 5%–10% of all cases of breast cancer, meaning that the widespread implementation of prophylactic mastectomy may significantly reduce the occurrence of breast cancer. However, prophylactic mastectomy is rarely performed in Korea. Therefore, in this study, we assessed Koreans' attitudes toward and awareness of preventive mastectomy. Methods This was a prospective study of a cohort of patients attending outpatient clinics and their relatives. Data were collected using self-administered questionnaires assessing sex, age, educational level, knowledge of breast cancer, understanding of prophylactic mastectomy, attitudes toward prophylactic mastectomy, and reasons for choosing prophylactic mastectomy. Results Sixty-five patients were included. Most patients (36.9%) were between 40 and 49 years of age and 58.4% were college graduates. Only six respondents (9%) understood prophylactic mastectomy, and 17 respondents (27%) stated that they would agree to undergo prophylactic mastectomy if necessary. Reasons given for refusing prophylactic mastectomy included aesthetic concerns (38%), the perception that it would not cure the disease (26%), possible surgical complications (24%), and financial cost (6%). Conclusions In this study, most of the respondents showed a poor knowledge of prophylactic mastectomy. Ultimately, it will be necessary to establish medical guidelines for patients with a high risk of breast cancer, with the objective of providing accurate information and proper treatment at hospitals. PMID:26848446

  5. Orographic precipitation, erosional unloading, and tectonic style

    NASA Astrophysics Data System (ADS)

    Hoffman, Paul F.; Grotzinger, John P.

    1993-03-01

    Comparative tectonics of the Thelon (1.97 Ga) and Wopmay (1.88 Ga) orogens of north-west Canada and the Grenville (1.1 Ga) and Alleghany (0.3 Ga) orogens of eastern North America support geophysical models linking orographic precipitation and erosion to tectonic style. Paleomagnetic data imply that the Thelon and Grenville orogenic fronts were favorably situated to face trade winds and experience monsoonal precipitation. High rates of uplift could have been balanced by erosional unloading. Consequently, the orogenic fronts are deeply eroded and lack thin-skinned foreland thrust-and-fold belts. Tectonic progradation was achieved instead by thermal activation of the orogenic footwall. Foreland basins, where preserved, are overfilled with sediments that are dominantly fluvial to shallow marine, compositionally mature, and progradationally stacked. The Wopmay and Alleghany orogenic fronts developed in rain shadows. Erosional unloading could not offset even modest rates of tectonically driven uplift, resulting in mass flow onto the foreland manifested by thin-skinned thrust-and-fold belts and associated foreland basins. Foreland basins are underfilled and well preserved, containing sediments that are dominantly deep water, compositionally immature, and aggradationally stacked. The nature of the Mauritanide orogenic front is consistent with it being the windward complement of the Alleghany front.

  6. Archean collisional tectonics in SW Montana

    SciTech Connect

    Mogk, D.; Rickmond, D.; Salt, K.; Clark, M.; Mueller, P.; Lafrenze, D.; Wooden, J.; Henry, D.

    1985-01-01

    The Archean continental crust of SW Montana evolved through alternating cycles of stable platform sedimentation followed by crustal thickening through collisional tectonics. The ancient sialic crust in the Beartooth Mountains served as the nucleus for accretion of younger terranes to the west. The oldest orogenic cycle recognized in the Beartooth Mountains involves a 3.4 Ga old supracrustal sequence which was metamorphosed in the granulite facies (T=700-800/sup 0/C, P=6Kb, 35/sup 0/C/Km); deep burial is interpreted as the result of collisional tectonic thickening. The second orogenic cycle is subduction related and has produced 2.8 Ga old andesites, 2.75 Ga old calc-alkaline intrusives, upper amphibolite grade metamorphism, transcurrent faulting (in the North Snowy Block and Yankee Jim canyon at 2.8 Ga) and nappe emplacement. In the central Beartooths post-orogenic granites intrude pelitic schists (T=600/sup 0/C, P=8Kb, 25/sup 0/C/Km). West of the Beartooths the basement consists of 2.75-2.70 Ga old, tectonically telescoped coarse clastics (Gallatin, Madison Ranges) and stable platform sequences (Gravelly, Tobacco Root, Ruby Ranges). Nappe formation and granulite-migmatite (700-750/sup 0/C) associations are common, suggesting deep burial through tectonic thickening. A later-kinematic mesozonal (8Kb) qtz diorite-granodiorite batholithic complex is present in the northern Madison Range. Quartzofeldspathic paragneisses in the westernmost Archean basement are derived from either a continental or island arc source.

  7. Laboratory plate tectonics: a new experiment.

    PubMed

    Gans, R F

    1976-03-26

    A "continent" made of a layer of hexagonally packed black polyethylene spheres floating in clear silicon oil breaks into subcontinents when illuminated by an ordinary incandescent light bulb. This experiment may be a useful model of plate tectonics driven by horizontal temperature gradients. Measurements of the spreading rate are made to establish the feasibility of this model.

  8. Plate tectonics of the Mediterranean region.

    PubMed

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries.

  9. Plate Tectonics and Continental Drift: Classroom Ideas.

    ERIC Educational Resources Information Center

    Stout, Prentice K.

    1983-01-01

    Suggests various classroom studies related to plate tectonics and continental drift, including comments on and sources of resource materials useful in teaching the topics. A complete list of magazine articles on the topics from the Sawyer Marine Resource Collection may be obtained by contacting the author. (JN)

  10. Tectonically Induced Anomalies Without Large Earthquake Occurrences

    NASA Astrophysics Data System (ADS)

    Shi, Zheming; Wang, Guangcai; Liu, Chenglong; Che, Yongtai

    2017-06-01

    In this study, we documented a case involving large-scale macroscopic anomalies in the Xichang area, southwestern Sichuan Province, China, from May to June of 2002, after which no major earthquake occurred. During our field survey in 2002, we found that the timing of the high-frequency occurrence of groundwater anomalies was in good agreement with those of animal anomalies. Spatially, the groundwater and animal anomalies were distributed along the Anninghe-Zemuhe fault zone. Furthermore, the groundwater level was elevated in the northwest part of the Zemuhe fault and depressed in the southeast part of the Zemuhe fault zone, with a border somewhere between Puge and Ningnan Counties. Combined with microscopic groundwater, geodetic and seismic activity data, we infer that the anomalies in the Xichang area were the result of increasing tectonic activity in the Sichuan-Yunnan block. In addition, groundwater data may be used as a good indicator of tectonic activity. This case tells us that there is no direct relationship between an earthquake and these anomalies. In most cases, the vast majority of the anomalies, including microscopic and macroscopic anomalies, are caused by tectonic activity. That is, these anomalies could occur under the effects of tectonic activity, but they do not necessarily relate to the occurrence of earthquakes.

  11. Cenozoic rift tectonics of the Japan Sea

    SciTech Connect

    Kimura, K.

    1988-08-01

    The Japan Sea is one of the back-arc basins in trench-arc systems bordering the western Pacific. Recent paleomagnetic works suggest the Japan Sea opened during early to middle Miocene. Radiometric and microfossil ages of the Cenozoic onland sequences in the Japanese Islands elucidate the rift tectonics of the Japan Sea. The rifting history is summarized as follows: nonmarine volcanic formations of prerift stage before 50 Ma, rift-onset unconformity at 40 Ma, nonmarine volcanic formations of synrift stage 20-33 Ma, breakup unconformity 19 Ma showing the opening of the Japan Sea, marine volcanic and sedimentary formations of synrift stage 14.5-18 Ma, beginning of regional subsidence 14.5 Ma corresponding to the end of the Japan Sea opening, marine sedimentary formations of postdrift stage after 14.5 Ma. Rifting is not limited to the synrift stage but is continued to the syndrift stage. Rifting led to a horst-and-graben structure. Thus, the Cenozoic onland sequences in the Japanese Islands are suited for a study of rift tectonics because the sequences were subaerially exposed by the late Miocene-Holocene island-arc tectonics. Rift tectonics cannot be studied as easily in most Atlantic-type passive margins.

  12. Plate Tectonics and Continental Drift: Classroom Ideas.

    ERIC Educational Resources Information Center

    Stout, Prentice K.

    1983-01-01

    Suggests various classroom studies related to plate tectonics and continental drift, including comments on and sources of resource materials useful in teaching the topics. A complete list of magazine articles on the topics from the Sawyer Marine Resource Collection may be obtained by contacting the author. (JN)

  13. Tectonic evolution of the terrestrial planets.

    PubMed

    Head, J W; Solomon, S C

    1981-07-03

    The style and evolution of tectonics on the terrestrial planets differ substantially. The style is related to the thickness of the lithosphere and to whether the lithosphere is divided into distinct, mobile plates that can be recycled into the mantle, as on Earth, or is a single spherical shell, as on the moon, Mars, and Mercury. The evolution of a planetary lithosphere and the development of plate tectonics appear to be influenced by several factors, including planetary size, chemistry, and external and internal heat sources. Vertical tectonic movement due to lithospheric loading or uplift is similar on all of the terrestrial planets and is controlled by the local thickness and rheology of the lithosphere. The surface of Venus, although known only at low resolution, displays features both similar to those on Earth (mountain belts, high plateaus) and similar to those on the smaller planets (possible impact basins). Improved understanding of the tectonic evolution of Venus will permit an evaluation of the relative roles of planetary size and chemistry in determining evolutionary style.

  14. Prevalence and Determinants of Diabetic Nephropathy in Korea: Korea National Health and Nutrition Examination Survey

    PubMed Central

    Ahn, Jae Hee; Yu, Ji Hee; Ko, Seung-Hyun; Kwon, Hyuk-Sang; Kim, Dae Jung; Kim, Jae Hyeon; Kim, Chul Sik; Song, Kee-Ho; Won, Jong Chul; Lim, Soo; Choi, Sung Hee; Han, Kyungdo; Cha, Bong-Yun

    2014-01-01

    Background Diabetic nephropathy is a leading cause of end stage renal disease and is associated with an increased risk of cardiovascular mortality. It manifests as albuminuria or impaired glomerular filtration rate (GFR), and the prevalence of diabetic nephropathy varies with ethnicity. The prevalence of diabetic nephropathy and its determinants in Korean adults have not previously been studied at the national level. This cross-sectional study was undertaken to ascertain the prevalence and determinants of albuminuria and chronic kidney disease (CKD) in Korean patients with diabetes. Methods The Korea National Health and Nutrition Examination Survey (KNHANES) V, conducted in 2011, was used to define albuminuria (n=4,652), and the dataset of KNHANES IV-V (2008-2011) was used to define CKD (n=21,521). Selected samples were weighted to represent the entire civilian population in Korea. Albuminuria was defined as a spot urine albumin/creatinine ratio >30 mg/g. CKD was defined as a GFR <60 mL/min/1.73 m2. Results Among subjects with diabetes, 26.7% had albuminuria, and 8.6% had CKD. Diabetes was associated with an approximate 2.5-fold increased risk of albuminuria, with virtually no difference between new-onset and previously diagnosed diabetes. Only systolic blood pressure was significantly associated with albuminuria, and old age, high serum triglyceride levels, and previous cardiovascular disease (CVD) were related with CKD in subjects with diabetes. Conclusion Korean subjects with diabetes had a higher prevalence of albuminuria and CKD than those without diabetes. Blood pressure was associated with albuminuria, and age, triglyceride level, and previous CVD were independent determinants of CKD in subjects with diabetes. PMID:24851205

  15. Tsunami Run-up Heights at Imwon Port, Korea

    NASA Astrophysics Data System (ADS)

    Cho, Yong-Sik; Cho, Jeong-Seon

    2015-04-01

    surveyed again. The run-up heights for both 1983 and 1993 Tsunami events are computed along the Eastern Coastline of the Korean Peninsula. Finally, a tsunami hazard map is generated based on the computed and observed run-up heights. Significant information such as proper evacuation routes, shelters and hot lines are included in the map. Acknowledgements The research described in this publication was supported by the National Research Foundation of Korea (Reference No. 2010-0022337).

  16. Initiation of plate tectonics from post-magma ocean thermo-chemical convection

    NASA Astrophysics Data System (ADS)

    Foley, B. J.; Bercovici, D. A.

    2013-12-01

    also the possibility of chemical differentiation which would lead to an initially unstable compositional density profile in the newly solidified mantle. We thus perform numerical models with an initially unstable temperature profile (approximating the silicate solidus) both with and without an initially unstable compositional density profile. All models show an initial overturn beneath a stagnant lid, followed by stagnant lid convection and the eventual onset of plate tectonic style convection. The timescale for initiating plate tectonics depends on the Rayleigh number, parameters for healing and damage, and on the degree of chemical differentiation during magma ocean solidification. Similar to the results of the scaling analysis, higher surface temperature retards the initiation of plate tectonics, due to the effects of lithospheric healing. Compositional buoyancy significantly reduces the timescale for initiating plate tectonics due to the increased negative buoyancy of the lithosphere (i.e. including both thermal and chemical buoyancy). Thus chemical differentiation during magma ocean solidification provides a significant boost to initiating plate tectonics in the Hadean Earth.

  17. Prevalence of minimal hearing loss in South Korea.

    PubMed

    Choi, Ji Eun; Ahn, Jungmin; Park, Hyun Woo; Baek, Sun-Young; Kim, Seonwoo; Moon, Il Joon

    2017-01-01

    This study evaluated the prevalence of minimal hearing loss (MHL) in South Korea based on the 2010 to 2012 Korea National Health and Nutrition Examination Survey. A total of 16,630 representative individuals (older than 12 years) who completed ear examinations and structured questionnaires were analyzed. Only participants who had normal tympanic membranes were included. MHL was categorized into the following three groups: 1) unilateral sensorineural hearing loss (USHL, pure-tone average (PTA) ≥ 15 dB in the affected ear), 2) bilateral sensorineural hearing loss (BSHL, 15 dB ≤ PTA < 40 dB in both ears), and 3) high-frequency sensorineural hearing loss (HFSHL, two or more high-frequency thresholds > 25 dB in either ear). To evaluate clinical symptoms, subjective hearing status, tinnitus, and quality of life of each MHL group were compared to those of normal-hearing listeners. The use of hearing aids (HAs) was also investigated in the MHL population. The prevalence of normal hearing and MHL were 58.4% and 37.4%, respectively. In univariate analyses, the prevalence of MHL increased with age. It was significantly increased in males. Regarding clinical symptoms, 13.0% and 92.1% of participants with MHL reported difficulties with hearing and annoying tinnitus, respectively. In multivariate analyses, these proportions were significantly higher in the MHL groups than in normal-hearing listeners. Participants with MHL also showed significantly lower Euro Qol-5D index scores than did normal-hearing listeners. Regarding hearing rehabilitation, among minimally hearing impaired participants with subjective hearing loss, only 0.47% of individuals used HAs. Our results reveal that MHL is common in South Korea. It is associated with significant subjective hearing loss, tinnitus, and poor quality of life. Therefore, clinicians need to pay attention to this special group and provide proper counselling and rehabilitative management.

  18. Prevalence of minimal hearing loss in South Korea

    PubMed Central

    Choi, Ji Eun; Ahn, Jungmin; Park, Hyun Woo; Baek, Sun-Young; Kim, Seonwoo; Moon, Il Joon

    2017-01-01

    This study evaluated the prevalence of minimal hearing loss (MHL) in South Korea based on the 2010 to 2012 Korea National Health and Nutrition Examination Survey. A total of 16,630 representative individuals (older than 12 years) who completed ear examinations and structured questionnaires were analyzed. Only participants who had normal tympanic membranes were included. MHL was categorized into the following three groups: 1) unilateral sensorineural hearing loss (USHL, pure-tone average (PTA) ≥ 15 dB in the affected ear), 2) bilateral sensorineural hearing loss (BSHL, 15 dB ≤ PTA < 40 dB in both ears), and 3) high-frequency sensorineural hearing loss (HFSHL, two or more high-frequency thresholds > 25 dB in either ear). To evaluate clinical symptoms, subjective hearing status, tinnitus, and quality of life of each MHL group were compared to those of normal-hearing listeners. The use of hearing aids (HAs) was also investigated in the MHL population. The prevalence of normal hearing and MHL were 58.4% and 37.4%, respectively. In univariate analyses, the prevalence of MHL increased with age. It was significantly increased in males. Regarding clinical symptoms, 13.0% and 92.1% of participants with MHL reported difficulties with hearing and annoying tinnitus, respectively. In multivariate analyses, these proportions were significantly higher in the MHL groups than in normal-hearing listeners. Participants with MHL also showed significantly lower Euro Qol-5D index scores than did normal-hearing listeners. Regarding hearing rehabilitation, among minimally hearing impaired participants with subjective hearing loss, only 0.47% of individuals used HAs. Our results reveal that MHL is common in South Korea. It is associated with significant subjective hearing loss, tinnitus, and poor quality of life. Therefore, clinicians need to pay attention to this special group and provide proper counselling and rehabilitative management. PMID:28196098

  19. Tectonic motion site survey of the National Radio Astronomy Observatory, Green Bank, West Virginia

    NASA Technical Reports Server (NTRS)

    Webster, W. J., Jr.; Allenby, R. J.; Hutton, L. K.; Lowman, P. D., Jr.; Tiedemann, H. A.

    1979-01-01

    A geological and geophysical site survey was made of the area around the National Radio Astronomy Observatory (NRAO) to determine whether there are at present local tectonic movements that could introduce significant errors to Very Long Baseline Interferometry (VLBI) geodetic measurements. The site survey consisted of a literature search, photogeologic mapping with Landsat and Skylab photographs, a field reconnaissance, and installation of a seismometer at the NRAO. It is concluded that local tectonic movement will not contribute significantly to VLBI errors. It is recommended that similar site surveys be made of all locations used for VLBI or laser ranging.

  20. Occupational respiratory cancer in Korea.

    PubMed

    Lee, Hye-Eun; Kim, Hyoung Ryoul

    2010-12-01

    Malignant mesothelioma and lung cancer are representative examples of occupational cancer. Lung cancer is the leading cause of cancer death, and the incidence of malignant mesothelioma is expected to increase sharply in the near future. Although information about lung carcinogen exposure is limited, it is estimated that the number of workers exposed to carcinogens has declined. The first official case of occupational cancer was malignant mesothelioma caused by asbestos exposure in the asbestos textile industry in 1992. Since then, compensation for occupational respiratory cancer has increased. The majority of compensated lung cancer was due to underlying pneumoconiosis. Other main causative agents of occupational lung cancer included asbestos, hexavalent chromium, and crystalline silica. Related jobs included welders, foundry workers, platers, plumbers, and vehicle maintenance workers. Compensated malignant mesotheliomas were associated with asbestos exposure. Epidemiologic studies conducted in Korea have indicated an elevated risk of lung cancer in pneumoconiosis patients, foundry workers, and asbestos textile workers. Occupational respiratory cancer has increased during the last 10 to 20 yr though carcinogen-exposed population has declined in the same period. More efforts to advance the systems for the investigation, prevention and management of occupational respiratory cancer are needed.