Abstract The Namche Barwa massif (NBM) in the Eastern Himalayan Syntaxis (EHS) hosts some of most active Cenozoic crustal deformation, magmatism, metamorphism, and extreme topographic relief on earth. crust‐mantle dynamics responsible for tectono‐magmatism NBM remains debated. We image detailed structures under using recordings a dense seismic array 400 3‐component node geophones 4,290 P‐wave receiver functions (PRFs). Our results show wide range negative phases middle lower crust weak Moho...

Abstract Large igneous provinces (LIPs) are commonly associated with mass extinctions. However, the precise relations between LIPs and their impacts on biodiversity is enigmatic, given that they can be asynchronous. It has been proposed environmental primarily related to sill emplacement. Therefore, structure of LIPs' magma storage system critical because it dictates occurrence timing extinction. We use surface-wave tomography image lithosphere under Permian Emeishan large province (ELIP) in...

Abstract Lithospheric shear wave velocity beneath the southeastern margin of Tibetan Plateau is obtained from Rayleigh tomography using earthquake data recorded by temporary ChinArray and permanent China Digital Seismic Array. Fundamental mode phase velocities at periods 20–100 s are determined used to construct 3‐D model. Low‐velocity anomalies appear along or close major faults in middle crust become a broad zone lower crust, suggesting block extrusion shallow diffuse deformation both...

Abstract Xinfengjiang Water Reservoir (XWR), located in the northeast of Guangdong Province, South China, has hosted a large number earthquakes since its impoundment. In order to understand potential triggering mechanisms reservoir‐induced seismicity that could help assess seismic hazard Greater Bay Area, most populated region this study, we construct high‐resolution shear‐wave velocity model shallow crust at depths from surface ∼10 km based on high‐density short‐period array recently...

The Tibetan Plateau's lower crustal composition and rheology dictate the tectonic surface deformation in response to India-Asia collision. Yet, their spatial variations under Plateau remain unclear. In this study, we forward calculated seismic velocities (i.e., Vp Vs) for three types of rocks presumed constitute continental crust. By comparing simulated observed velocities, infer current Plateau. results show west Tibet Pamir is predominantly composed eclogite, suggesting ongoing intense...

Abstract The northeastern Tibetan Plateau has undergone active shortening due to the India‐Asia collision and been an ideal place for studying growth of plateau. To reveal deep structure that is responsible geological observations in NE Tibet, we have constructed a 3‐D shear wave velocity model from Rayleigh waves recorded by 36 stations Northeast Seismic experiment. First, two‐plane‐wave tomography method was applied compute average 2‐D variations phase velocities period range 20 100 s....

Three-dimensional shear wave velocity and radial anisotropy models of the crust upper mantle beneath NE Tibetan plateau are constructed from new measurements Love dispersions (20–77s) previously obtained Rayleigh (20–87s) using a two-plane-wave method. The mid-lower is characterized with positive (VSH > VSV) large strength Qinling Qilian Mountains small values Anyemaqen Mountain. can be explained by horizontal alignment anisotropic minerals in due to crustal flow. lithosphere above 90 km...

Abstract The northward extent of subducted Indian plate is a fundamental component hypotheses explaining deformation and magmatism within the Tibetan Plateau. Yet, these aspects are debated in west Tibet. Here we report new three‐dimensional lithospheric structure seismic velocity radial anisotropy under Tibet constructed from Rayleigh Love wave phase maps at periods 20–167 20–125 s, respectively. Our results show mantle to be subhorizontally across Bangong‐Nujiang suture Qiangtang terrane,...

Abstract Large earthquakes that occur away from plate boundaries (i.e., large intraplate earthquakes), though rare, could cause heavy damage. Understanding their causes help with seismic hazard assessment. In this study, we image the seismogenic structure under 1969 Ms6.4 Yangjiang earthquake within stable South China Block a high‐resolution three‐dimensional shear‐wave velocity model constructed ambient noise tomography based on dense nodal array. The images relatively low velocities at...

Array measurements of surface wave phase velocity can be biased by multipath arrivals. A two-plane-wave (TPW) inversion method, in which the incoming wavefield is represented interference two plane waves, able to account for effect and solve laterally varying velocity. Despite broad applications TPW its usage has been limited Rayleigh waves. In this study, we have modified approach applied it Love Main modifications include decomposing amplitude on transverse component x y components a local...

Abstract The tectonic source for widespread volcanism in northeast China has not been completely understood. We develop a 3‐D SH velocity model NE that provides new constraints to the origin of volcanism. is constructed from fundamental mode Love waves at periods 20–125 s recorded 269 broadband seismic stations. Changbai Mountain characterized by significant low lower crust and uppermost mantle, which probably results mantle upwelling due subduction Pacific plate. A fast thin lid ~75 km...

Abstract Lithospheric weakness is essential in subduction initiation. Spreading ridges are divergent plate boundaries which may represent lithospheric and promote Natural examples of ridge‐inversed along spreading have been proposed (e.g., the Proto‐South China Sea subduction). Although, dynamic evolution has investigated by geodynamical numerical modeling previously, it remains obscure, especially influence thermal state geometries on initiation evolution. We establish two‐dimensional...

Abstract The Pamir‐Hindu‐Kush region is widely cited as a best place to study opposing continental subduction on Earth. Yet, subducting slab morphology of the Indian and Asian plates under this remains elusive. Here we report new shear wave velocity radial anisotropy models from Rayleigh Love tomography constrain geometry these two slabs. Together with previous tomographic studies, show that exhibits along‐strike variation subhorizontally underthrusting into Pamir high‐angle Hindu‐Kush. We...

Abstract The northeastern (NE) Tibetan plateau has been a prime site to understand the dynamic processes responsible for rise and lateral growth of plateau. Here we construct high‐resolution lithospheric scale isotropic SH wave velocity model (down depth 130 km) NE its adjacent regions based on measurements fundamental‐mode Love dispersions (20–100 s) with seismic data recorded by ChinArray II China Digital Seismic Array using two‐plane method. Prominent slow ( V ) is observed in midlower...

Abstract The Yinggehai Basin (YB) in the northwest of South China Sea (SCS) has preserved complete evolution Red River Fault (RRF), whose motion over time largely contributed to shaping current tectonic framework southeastern Tibetan Plateau and Indochina Block. Here we, for first time, image RRF, crustal architecture, crust‐mantle boundary (i.e., Moho) detail under YB from two high‐resolution 40‐km‐depth seismic reflection pre‐stack migration profiles. Our images provide direct evidence...

ABSTRACT An understanding of mantle dynamics occurring beneath the Tibetan plateau requires a detailed image its seismic velocity and anisotropic structure. Surface waves at long periods (>50 s) could provide such critical information. Though Rayleigh-wave phase maps have been constructed in regions using ambient-noise tomography (ANT) regional earthquake surface-wave tomography, Love-wave maps, especially those longer s), are rare. In this study, two-plane-wave teleseismic is applied...