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Earthquake Science 2017年第5期30卷 229-238页

作者： Ping Zhang huajian yao Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space SciencesUniversity of Science andTechnology of ChinaHefei 230026AnhuiChina National Geophysical Observatory at Mengcheng MengchengAnhuiChina

Accurate determination of seismic velocity of the crust is important for understanding regional tectonics and crustal evolution of the Earth. We propose a stepwise joint linearized inversion method using surface wave dispersion, Rayleigh wave ZH ratio （i.e., ellipticity）, and receiver function data to better resolve 1D crustal shear wave velocity （Vs） structure. Surface wave dispersion and Rayleigh wave ZH ratio data are more sensitive to absolute variations of shear wave speed at depths, but their sensi- tivity kernels to shear wave speeds are different and complimentary. However, receiver function data are more sensitive to sharp velocity contrast （e.g., due to the existence of crustal interfaces） and Vp/Vs ratios. The stepwise inversion method takes advantages of the complementary sensitivities of each dataset to better constrain the Vs model in the crust. We firstly invert surface wave dispersion and ZH ratio data to obtain a 1D smooth absolute vs model and then incorporate receiver function data in the joint inver- sion to obtain a finer Vs model with better constraints on interface structures. Through synthetic tests, Monte Carlo error analyses, and application to real data, we demonstrate that the proposed joint inversion method can resolve robust crustal Vs structures and with little initial model dependency.

关键词： Joint inversion Receiver function Surfacewave dispersion Rayleigh wave ZH ratio· Shearwave velocity

Frequency-dependent rupture process,stress change,and seismogenic mechanism of the 25 April 2015 Nepal Gorkha M_w 7.8 earthquake

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Science China Earth Sciences 2017年第4期60卷 796-808页

作者： YIN JiuXun yao huajian YANG HongFeng LIU Jing QIN WeiZe ZHANG HaiJiang Laboratory of Seismology and Physics of Earth 's Interior & School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China Earth System Science Programme Faculty of Science Chinese University of Hong Kong Shatin NT Hong Kong 999077 China National Geophysical Observatory at Mengcheng University of Science and Technology of China Mengcheng 233500 China State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China

On 25 April 2015,an M_w 7.8 earthquake occurred on the Main Himalaya Thrust fault with a dip angle of^7° about77 km northwest of Kathmandu,*** Nepal Gorkha event is the largest one on the Himalayan thrust belt since *** we use the compressive sensing method in the frequency domain to track the seismic radiation and rupture process of this event using teleseismic P waves recorded by array stations in North *** also compute the distribution of static shear stress changes on the fault plane from a coseismic slip *** results indicate a dominant east-southeastward unilateral rupture process from the epicenter with an average rupture speed of ~3 km s^(-1).Coseismic radiation of this earthquake shows clear frequency-dependent *** lower frequency(0.05-0.3 Hz) radiation mainly originates from large coseismic slip regions with negative coseismic shear stress *** comparison,higher frequency(0.3-0.6 Hz) radiation appears to be from the down-dip part around the margin of large slip areas,which has been loaded and presents positive coseismic shear stress *** propose an asperity model to interpret this Nepal earthquake sequence and compare the frequency-dependent coseismic radiation with that in subduction *** frequency-dependent radiation indicates the depth-varying frictional properties on the plate interface of the Nepal section in the main Himalaya thrust system,similar to previous findings in oceanic subduction *** findings provide further evidence of the spatial correlation between changes of static stress status on the fault plane and the observed frequency-dependent coseismic radiation during large *** results show that the frequency-dependent coseismic radiation is not only found for megathrust earthquakes in the oceanic subduction environment,but also holds true for thrust events in the continental collision zone.

关键词： Pg wave Tomography Crust Velocity Anisotropy Volcano

Imaging mantle transition zone discontinuities in southwest China from dense array ambient noise interferometry

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Earthquake Science 2018年第5期31卷 301-310页

作者： Jikun Feng huajian yao Weitao Wang Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space SciencesUniversity of Science and Technology of China Mengcheng National Geophysical Observatory University of Science and Technology of China Institute of Geophysics China Earthquake Administration

Body waves retrieved from ambient noise cross-correlation functions（NCFs） have been reported by more and more recent studies in addition to the dominant recovered surface waves. And one of important applications of these recovered body waves is to investigate the structure of discontinuities within the mantle transition zone（MTZ）. In this study, clear body wave phases reflected from the MTZ discontinuities at 410 km and 660 km have been observed on the NCFs in the frequency band of 0.1–0.2 Hz from a dense regional seismic array in southwest China. The original timedomain reflected signals in the NCFs were first converted to the depth-domain NCFs based on a velocity model before they were further stacked spatially within different bins. Then the depth-domain NCFs were stacked to investigate the lateral variations of the MTZ discontinuities, that is, the 410-km and 660-km discontinuities. Our results exhibit a simple and lateral coherent P;P phase and a much more complicated P;P phase along two profiles, which are in good agreement with mineralogical prediction and recent receiver function studies in the same area. This interferometric method can provide stable reflected body wave phases mainly in the frequency band 0.1–0.2 Hz due to the secondary microseism noise, which can be potentially used for high-resolution mantle interface imaging. This approach is also a good complement to traditional imaging methods, such as receiver function imaging.

关键词： ambient noise interferometry mantle transition zone 410-km and 660-km discontinuities reflected body waves southwest China

High-resolution crustal velocity structure in the Shanxi rift zone and its tectonic implications

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Science China Earth Sciences 2021年第5期64卷 728-743页

作者： Liting DOU huajian yao Lihua FANG Song LUO Meiqin SONG Xiaomei YAN Cheng CHENG Shanxi Earthquake Administration Taiyuan 030021China Laboratory of Seismology and Physics of the Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng 233500China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Institute of Geophysics China Earthquake AdministrationBeijing 100081China

The Shanxi rift zone,located in the Trans-North China Orogen(TNCO)of the North China Craton(NCC),is wellknown for hosting large intraplate earthquakes in continental *** TNCO is a suture zone formed by the amalgamation of the eastern and the western blocks of the *** its formation,it was reactived and deformed by later tectonic activities,which result in complex lithospheric ***,the detailed crustal structure of the Shanxi rift zone is critical for understanding the tectonics and seismogenic mechanism in this area,which will shed new lights on the formation and dynamic evolution of the *** this study,we applied ambient noise tomography based on 18 months continuous records from 108 seismic stations located in Shanxi and its surroundings,in order to constrain its detailed crustal *** measured 4437 Rayleigh wave phase velocity dispersion curves in the period of 5–45 s from the cross-correlation ***,a surface wave direct inversion algorithm based on surface-wave ray tracing was used to resolve a 3-D S-wave velocity model in the upper 60 km with lateral resolution of~50–80 *** tomographic images show that the sedimentary thickness of the Taiyuan Basin is less than 5 *** depth of 0–10 km,we observe a good correlation between the imaged structural variations with geological and topographic features at the *** example,the center of rift shows low-velocity anomalies and the uplifting areas on both sides are characterized by high velocity *** western and eastern boundaries of the slow materials coincide with the faults that control the *** slow material extends from the shallow surface to depth of about 15 km but it getting smaller in shape at deeper *** the Taiyuan Basin,Linfen Basin,and Yuncheng Basin in the central and southern parts,the structure is dominant by slow materials in the upper crust but changes to strong high-velocity anomalies in the lower crust and the uppermost mantle at

关键词： Shanxi rift zone Ambient noise tomography S-wave velocity structure Magmatic underplating Earthquake distribution

3D v_P and v_S models of southeastern margin of the Tibetan plateau from joint inversion of body-wave arrival times and surface-wave dispersion data

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Earthquake Science 2017年第1期30卷 17-32页

作者： Lina Gao Haijiang Zhang huajian yao Hui Huang School of Geoexploration Science and Technology Jilin University Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of China National Geophysical Observatory at Mengcheng Department of Earth Atmospheric and Planetary SciencesMassachusetts Institute of Technology

A new 3D velocity model of the crust and upper mantle in the southeastern （SE） margin of the Tibetan plateau was obtained by joint inversion of body- and sur- face-wave data. For the body-wave data, we used 7190 events recorded by 102 stations in the SE margin of the Tibetan plateau. The surface-wave data consist of Rayleigh wave phase velocity dispersion curves obtained from ambient noise cross-correlation analysis recorded by a dense array in the SE margin of the Tibetan plateau. The joint inversion clearly improves the Vs model because it is constrained by both data types. The results show that at around 10 km depth there are two low-velocity anomalies embedded within three high-velocity bodies along the Longmenshan fault system. These high-velocity bodies correspond well with the Precambrian massifs, and the two located to the northeast of 2013 Ms 7.0 Lushan earthquake are associated with high fault slip areas during the 2008 Wenchuan earthquake. The aftershock gap between 2013 Lushan earthquake and 2008 Wenchuan earthquake is associated with low-velocity anomalies, which also acts as a barrier zone for ruptures of two earthquakes. Generally large earthquakes （M 〉 5） in the region occurring from 2008 to 2015 are located around the high-velocity zones, indicating that they may act as asperities for these large earthquakes. Joint inversion results also clearly show that there exist low-velocity or weak zones in the mid-lower crust, which are not evenly distributed beneath the SE margin of Tibetan plateau.

关键词： Joint inversion - Body waves Surface waves Aftershock gap The southeastern margin of Tibetan plateau

Shallow crustal velocity structures revealed by active source tomography and fault activities of the Mianning–Xichang segment of the Anninghe fault zone, Southwest China

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Earth and Planetary Physics 2022年第2期6卷 204-212页

作者： XiHui Shao huajian yao Ying Liu HongFeng Yang BaoFeng Tian LiHua Fang Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng Hefei 233500China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Earth System Science Programme Faculty of ScienceThe Chinese University of Hong KongHong Kong 999077China Shenzhen Research Institute The Chinese University of Hong KongShenzhen 518057China Institute of Geophysics China Earthquake AdministrationBeijing 100089China

The Anninghe fault is a large left-lateral strike-slip fault in southwestern China. It has controlled deposition and magmatic activities since the Proterozoic, and seismic activity occurs frequently. The Mianning-Xichang segment of the Anninghe fault is a seismic gap that has been locked by high stress. Many studies suggest that this segment has great potential for large earthquakes(magnitude >7). We obtained three vertical velocity profiles of the Anninghe fault(between Mianning and Xichang) based on the inversion of P-wave first arrival times. The travel time data were picked from seismograms generated by methane gaseous sources and recorded by three linearly distributed across-fault dense arrays. The inversion results show that the P-wave velocity structures at depths of 0-2 km corresponds well with the local lithology. The Quaternary sediments have low seismic velocities, whereas the igneous rocks,metamorphic rocks, and bedrock have high seismic velocities. We then further discuss the fault activities of the two fault branches of the Anninghe fault in the study region based on small earthquakes(magnitudes between ML 0.5 and ML 2.5) detected by the Xichang *** eastern fault branch is more active than the western branch and that the fault activities in the eastern branch are different in the northern and southern segments at the border of 28°21′N. The high-resolution models obtained are essential for future earthquake rupture simulations and hazard assessments of the Anninghe fault zone. Future studies of velocity models at greater depths may further explain the complex fault activities in the study region.

关键词： Anninghe fault zone shallow crust P-wave velocity methane gaseous source fault activity

High-resolution 3D crustal S-wave velocity structure of the MiddleLower Yangtze River Metallogenic Belt and implications for its deep geodynamic setting

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Science China Earth Sciences 2019年第9期62卷 1361-1378页

作者： Song LUO huajian yao Qiusheng LI Weitao WANG Kesong WAN Yafeng MENG Bin LIU Laboratory of Seismology and Physics of the Earth’s Interior School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China National Geophysical Observatory at Mengcheng University of Science and Technology of China Mengcheng 233500 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Institute of Geophysics Chinese Earthquake Administration Beijing 100081 China

The Middle-Lower Yangtze River Metallogenic Belt(MLYMB) is an important mineral resource region in ***-resolution crustal models can provide crucial constraints to understand the ore-forming processes and geodynamic setting in this region. Using ambient seismic noise from 107 permanent and 82 portable stations in the MLYMB and the adjacent area,we present a new high-resolution 3D S-wave velocity model of this region. We first extract 5–50 s Rayleigh wave phase velocity dispersion data by calculating ambient noise cross-correlation functions(CFs) and then use the surface wave direct inversion method to invert the mixed path travel times for the 3D S-wave velocity structure. Checkerboard tests show that the horizontal resolution of the 3D S-wave velocity model is approximately 0.5°–1.0° and that the vertical resolution decreases with increasing noise and depth. Our high-resolution 3D S-wave velocity model reveals:(1) AV-shaped high-velocity zone(HVZ) is located in the lower crust and the uppermost mantle in the study region. The western branch of the HVZ passes through the Jianghan Basin,the Qinling-Dabie orogenic belt and the Nanxiang Basin. The eastern branch, which almost completely covers the main body of the MLYMB, is located near the Tanlu Fault. The low-velocity anomalies between the western and eastern branches are located in the area of the Qinling-Dabie orogenic belt.(2) High-velocity uplifts(HVUs) are common in the crust of the MLYMB,especially in the areas near the Tanlu Fault, the Changjiang Fault and the Yangxin-Changzhou Fault. The intensities of the HVUs gradually weaken from west to east. The V-shaped HVZ in the lower crust and uppermost mantle and the HVUs in the middle and lower crust likely represent cooled mantle intrusive rocks. During the Yanshanian period, fault systems formed in the MLYMB due to the convergence between the South China Plate and the North China Plate, the multiple-direction drifting of the PaleoPacific Plate and its subd

关键词： Middle-Lower Yangtze River Metallogenic Belt Ambient noise Surface wave Crustal structure Mineralization dynamics

High-resolution velocity structure and seismogenic potential of strong earthquakes in the Bamei-Kangding segment of the Xianshuihe fault zone

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Science China Earth Sciences 2023年第9期66卷 1960-1978页

作者： Yan ZHAO Junlun LI Jian XU huajian yao Gaohua ZHU Hongfeng YANG Jinyu ZHANG Renqi LU Laboratory of Seismology and Physics of the Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology Hefei 230026China Key Laboratory of Marine Geology and Environment CASQingdao 266071China Earth System Science Programme Faculty of ScienceThe Chinese University of Hong KongHong Kong 999077China State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China

On September 5,2022,a strong MS6.8 earthquake struck the Luding area in the Kangding-Moxi segment of the Xianshuihe fault zone,which is the northern boundary of the Sichuan-Yunnan rhombic block,causing considerable *** Bamei-Kangding segment of the Xianshuihe fault zone,which is located only tens of kilometers away from the Luding earthquake,has hosted frequent moderate to strong earthquakes in history and is a dangerous earthquake-prone ***,it is critical to investigate the regional seismogenic environment for strong earthquakes and to evaluate the impact of the Luding earthquake in this *** this purpose,we deployed a dense seismic array comprising over 200 short-period nodes in this region from July to August,2022 and acquired seismic ambient noise for over 30 *** the collected data,we conducted surface wave tomography and obtained a high-resolution 3-D shear wave velocity model for the regional shallow crust down to 8 km in *** key findings include:(1)the Bamei-Kangding segment of the Xianshuihe fault zone exhibits widespread stripped lowvelocity anomalies,suggesting shear movements at a relatively high temperature of the Xianshuihe fault zone;the Zheduoshan granitic pluton situated between the Zheduotang and southern Selaha faults shows a distinct low-velocity anomaly,which may be attributed to the localized high-temperature anomaly resulted by a deep magmatic heat source and the recent rapid uplift of the Zheduoshan area;(2)a ten-kilometer-wide high velocity body found below 4 km in depth near the Zhonggu area in the Bamei segment coincides with the seismic gap of moderate to strong earthquakes in this region,suggesting that the high velocity body may act as a seismic barrier;(3)the heterogeneity of the velocity structure along the Bamei-Kangding segment of the Xianshuihe fault zone corresponds to the regional changes in temperature,which reveals the reason for the spatially varying seismogenic potential in this segment;e

关键词： Xianshuihe fault zone Bamei-Kangding segment Luding earthquake Dense-array ambient noise tomography Seismogenic environment for moderate to strong earthquakes

同方期刊数据库

Preface to the special issue on complicated features on seismic sources and deep structures

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Earthquake Science 2021年第1期34卷 1-2页

作者： Yuan Gao Lisheng Xu huajian yao Xiaobo Tian Key Laboratory of Earthquake Prediction Institute of Earthquake ForecastingChina Earthquake AdministrationBeijing 100036China Institute of Geophysics China Earthquake AdministrationBeijing 100081China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

Earthquake is a kind of natural phenomenon in the *** seismology has been developed quickly since modern digital seismometers were applied to *** seismic records,seismologists study source properties of the earthquakes and detect multi-scale structural variations in the crust,mantle,and *** is complicated,including seismicity and seismic sources.

关键词： seismic Earthquake sources

Detailed sedimentary structure of the Mianning segment of the Anninghe fault zone revealed by H/V spectral ratio

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Earthquake Research Advances 2023年第3期3卷 19-29页

作者： Zeqiang Chen huajian yao Xihui Shao Song Luo Hongfeng Yang Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng233500China CAS Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei230026China Earth System Science Programme Faculty of ScienceThe Chinese University of Hong KongHong Kong999077China Shenzhen Research Institute The Chinese University of Hong KongShenzhen518057China

The Anninghe fault is a major left-lateral strike-slip fault in southwest China and a seismic gap with a potential earthquake larger than MW 7.0 lies in the Mianning-Xichang segment according to recent *** shallow structure of this region can offer a glimpse into the geometry of the fault,which plays an important role in earthquake hazard *** further investigate the sedimentary structure of the Anninghe fault zone,two dense linear arrays with a station spacing of around 80 m were deployed across the *** this study,the H/V spectral ratio(HVSR),together with its peak frequency at each station site,was obtained by applying the Nakamura *** findings demonstrate that the peak frequency behaves in high correlation with lithology and is controlled by *** in foothills or regions with magmatic intrusion shows a single peak at about 2–3 *** locations with abundant Quaternary sedimentation,such as Anninghe valleys and fracture zones,another low-frequency peak around 0.4 Hz can be noticed in *** using the empirical relationship,the thickness of the sedimentary layer around the fault fracture zone is estimated to be 300–600 ***,the sedimentary interface shows a downward dip to the east,possibly influenced by the east-west extrusion *** the resonance effect,buildings with 6–9 stories in the valley area of the Anninghe require additional attention in earthquake hazard prevention.

关键词： HVSR Shallow structure Anninghe fault zone Sediment Earthquake hazard prevention