A5027283087- earthquake and tectonic studies
- High-pressure geophysics and materials
- Geological and Geochemical Analysis
- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Geological and Geophysical Studies
- Geophysics and Sensor Technology
- Hydrocarbon exploration and reservoir analysis
- Geochemistry and Geochronology of Asian Mineral Deposits
- Geological and Tectonic Studies in Latin America
- Methane Hydrates and Related Phenomena
- Earthquake Detection and Analysis
- Seismology and Earthquake Studies
- Ocean Waves and Remote Sensing
- Geological formations and processes
- Geology and Paleoclimatology Research
- Thermodynamic and Structural Properties of Metals and Alloys
- Seismic Performance and Analysis
- Medical Imaging Techniques and Applications
- Geological Studies and Exploration
- Geochemistry and Geologic Mapping
- Tree Root and Stability Studies
- Material Properties and Applications
- Heat Transfer and Numerical Methods
- Landslides and related hazards
Chinese Academy of Geological Sciences
2024
New Mexico State University
2002-2015
Cornell University
1983
INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This has been produced by crustal thickening behaves as fluid on the time scale of Himalayan deformation. It is confined south structurally imbricated Indian crust underlying Tethyan High Himalaya underlain, apparently, stiff mantle lid. The results suggest during Neogene underthrusting acted plunger, displacing middle to north while at same contributing this melting...
Seismic data from central Tibet have been combined to image the subsurface structure and understand evolution of collision India Eurasia. The 410- 660-kilometer mantle discontinuities are sharply defined, implying a lack subducting slab beneath plateau. appear slightly deeper northern Tibet, that average temperature above transition zone is about 300 degrees C hotter in north than south. There prominent south-dipping converter uppermost might represent top Eurasian lithosphere underthrusting margin
This paper reports the regional propagation characteristics of high-frequency Pn, Pg, Sn and Lg waves (0.5 to 2 Hz) Pg velocities for several regions in Central Asia, Tibet India. An important result is that propagate efficiently uppermost mantle beneath most Tibetan Plateau. Also, transmission not affected by crossing many physiographic tectonic boundaries, such as Indus-Tsangpo suture. These observations are similar stable continental shield regions. Efficient also observed across Tarim...
SUMMARY Crustal and upper-mantle seismic discontinuities beneath eastern Turkey are imaged using teleseismic S-to-P converted phases. Three crustal phases observed: the Moho with depth ranging between 30 55 km, indicating variable tectonic regimes within this continental collision zone; an upper-crustal discontinuity at approximately 10 km depth; various low-velocity zones, possibly associated recent Quaternary volcanism. Imaging of upper mantle is complicated by 3-D geometry region, in...
Research Article| July 01, 2010 Small-scale convection at the edge of Colorado Plateau: Implications for topography, magmatism, and evolution Proterozoic lithosphere J.W. van Wijk; Wijk * 1Department Earth Atmospheric Sciences, University Houston, 312 Science Bldg. 1, Texas 77204, USA *E-mail: jwvanwijk@uh.edu. Search other works by this author on: GSW Google Scholar W.S. Baldridge; Baldridge 2Earth Environmental Sciences Division, Los Alamos National Laboratory, Alamos, New Mexico 87545, J....
In the summer of 1998, project INDEPTH recorded a 400 km long NNW–SSE wide-angle seismic profile in central Tibet, from Lhasa terrane across Banggong-Nujiang suture (BNS) at about 89.5°E and into Qiangtang terrane. Analysis P-wave data reveals that (1) crustal thickness is 65 ± 5 beneath line; (2) there no 20 step Moho vicinity BNS, as has been suggested to exist along-strike east based on prior fan profiling; (3) thick high-velocity lower layer evident along length (20–35 thick, 6.5–7.3...
Fourier spectra of crustal guided Lg waves are collected to study seismic attenuation, or Q , along the INDEPTH profiles. The 1 Hz ( 0 ) values measured between many pairs two stations and input a back projection algorithm obtain laterally varying models. Along III profile in central Tibet, model consists low nearly constant ∼90. These consistent with abnormally high temperature as well partial melts crust. II southern Tibet increase southward. They extremely (∼60) over northernmost segment...
Teleseismic traveltime data are inverted for mantle Vp and Vs variations beneath a 1400 km long line of broadband seismometers extending from eastern New Mexico to western Utah. The model spans 600 the moho with resolution ∼50 km. Inversions show sharp, large‐magnitude velocity contrast across Colorado Plateau‐Great Basin transition ∼200 below crust. Also imaged is fast anomaly 300 NW portion array. Very slow velocities Great imply partial melting and/or anomalously wet mantle. We propose...
Surface waves recorded by the nine broad-band stations of INDEPTH II experiment are analysed to study crustal structure southern Tibet. Their frequency range is between approximately 0.015 and 0.050 Hz (i.e. 20 60 s period). Phase velocity dispersion curves calculated for regions north south Tsangpo suture, using Wiener filtering fundamental mode Rayleigh incident upon array with different backazimuths. The two inverted obtain S-wave models suture. They show that a low-velocity layer present...
The northeastern margin of the Tibetan Plateau, which includes Qiangtang and Songpan-Ganzi terranes as well Kunlun Shan Qaidam Basin, continues to deform in response ongoing India–Eurasia collision. To test competing hypotheses concerning mechanisms for this deformation, we assembled a high-quality data set approximately 14 000 P- 4000 S-wave arrival times from earthquakes at teleseismic distances International Deep Profiling Tibet Himalaya, Phase IV broad-band seismometer deployments. We...
Abstract We use ambient‐noise tomography to map regional differences in crustal Rayleigh‐wave group velocities with periods of 8–40 s across north Tibet using the International Deep Profiling and Himalaya phase IV arrays (132 stations, deployed for 10–24 months). For 8–24 (sensitive midcrustal depths ~5–30 km), we observe striking velocity changes Bangong‐Nujiang Jinsha suture zones as well Kunlun‐Qaidam boundary. From south north, see higher beneath Lhasa terrane, lower Qiangtang,...
Shear-wave splitting measurements from SKS and SKKS phases show fast polarization azimuths that are subparallel to North American absolute plate motion within the central Rio Grande Rift (RGR) Colorado Plateau (CP) through western rim of CP, with anisotropy beneath CP RGR showing a remarkably consistent pattern mean azimuth 40° 6°E N. Approaching southeast, anisotropic directions become northnortheast-south-southwest (NNE-SSW), rotate counter clockwise north-south in CP-GB transition, then...
Abstract The propagation efficiencies of the regional phases Lg and Pn are indicative how active recent tectonics influence crust uppermost mantle properties, respectively. In this study, scale lateral heterogeneity attenuation for region in around southern Tibetan Plateau is investigated. data set comprised seismograms recorded at Chinese Digital Seismogram Network (CDSN) station LSA from events with epicentral distances within 11°. Attenuation calculated using spectral methods assuming...
The alternation characteristics of the crust in southernmost Tibetan plateau are determined from analysis S‐wave coda recorded at a temporary broadband station deployed during 1994 INDEPTH‐II experiment. A method for determining Qc is developed which utilizes spectrogram observed single station. average quality factor this continent‐continent collision zone (f) = (160 ± 69) ( f / 0 ) 1.11±0.19 , 1 < 4, where 1Hz. results consistent with other measurements continental collisional...