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Lithospheric structure beneath Ordos Block and surrounding areas from joint inversion of receiver function and surface wave dispersion

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Science China Earth Sciences 2022年第7期65卷 1399-1413页

作者： Jianping WU Yaning LIU Shijun ZHONG weilai wang Yan CAI Wei wang Jing LIU Institute of Geophysics China Earthquake AdministrationBeijing 100081China Beijing Earthquake Agency Beijing 100080China

Ordos Block has undergone rapid uplift,and a series of rift basins have been formed around the block since the Cenozoic,but the formation mechanisms remain controversial.A high-resolution 3 D velocity structure of crust and mantle is important for understanding the lithospheric deformation and deep dynamic process.A here we present a 3 D S-wave velocity structure of the crust and upper mantle in the Ordos Block and surrounding regions by joint inversion of receiver functions and surface wave data from a dense broadband seismic *** lithosphere of the Ordos Block exhibits an obvious highvelocity *** the east and north of the Ordos and the southwestern part of the Tibetan Plateau,obvious low-velocity anomalies are detected in the upper mantle and extend into the *** lithosphere of the Ordos Block is thick in the center and thin at the edge,while the crust is relatively thin in the center and thick in the southwest and *** crustal thickness of the tensional basin in the north is greater than that in the central *** suggest that the outward expansion of the mantle thermal materials in eastern Tibet and the upper mantle thermal upwelling in the eastern part of the North China Craton lead to the non-uniform lithospheric thinning,temperature rise and density reduction of the Ordos *** additional buoyancy and thermodynamic effects provided by them contributed to the continuous uplift of the Ordos Block since the *** by the extrusion of Tibetan Plateau,the crustal thickening and rapid uplift occur in the southwestern and northern parts of the Ordos *** lithospheric structures of the Alxa and Ordos Blocks are different,and they may belong to different independent blocks before the Mesozoic.

关键词： Ordos North China Craton Lithospheric structure S-wave velocity structure Receiver function Surface wave

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Liquid-phase hydrodechlorination of trichloroethylene driven by nascent H_(2)under an open system:Hydrogenation activity,solvent effect and sulfur poisoning

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Journal of Environmental Sciences 2021年第10期33卷 96-106页

作者： weilai wang Fan Zhang Yunfei Zhang Lei Xu Yuansheng Pei Junfeng Niu State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Research Center for Eco-Environmental Engineering Dongguan University of TechnologyDongguan 523808China

Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene(TCE).In this work,the liquid-phase hydrogenation of TCE by Raney Ni(R-Ni)and Pd/C under an open system have been studied,in which nascent H_(2)(Nas-H_(2))generated in situ from the cathode acted as a hydrogen *** results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H_(2)bubbles from the ***,the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated,*** results showed that NO_(3)^(-) and acetonitrile can form a competitive reaction with TCE;Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts,and have a stronger inhibitory effect on Pd/*** work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.

关键词： Nascent H_(2) Hydrogenation Air flotation Trichloroethylene Sulfur poisoning

Three dimensional velocity model and its tectonic implications at China Seismic Experimental Site,eastern margin of the Tibetan Plateau

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Science China Earth Sciences 2024年第7期67卷 2268-2290页

作者： Jianping WU Yan CAI Wei wang weilai wang Changzai wang Lihua FANG Yaning LIU Jing LIU Institute of Geophysics China Earthquake AdministrationBeijing 100081China Beijing Baijiatuan Earth Science National Observation and Research Station Beijing 1095China Beijing Earthquake Agency Beijing 100080China

The China Seismic Experimental Site(CSES)is located at the intersection of the Tibetan Plateau,South China Block,and Indian Plate and has complex geological settings and intense crustal deformation,making it one of the most seismically active areas in Chinese mainland.A high-resolution,three-dimensional(3D)crust-mantle velocity structure is crucial for understanding seismotectonic environments,lithospheric deformation mechanisms,and deep dynamic *** first constructed a high-vertical-resolution 3D initial velocity model using the joint inversion of receiver functions and surface waves and then obtained a 3D P-and S-wave velocity model(CSES-VM1.0)with the highest lateral resolution of 0.25°for the CSES using double-difference *** to the limitations of the Sn observation data,the resolution of the S-wave velocity model in the lower crust and upper mantle was reduced,making it closer to the initial model provided by joint inversion.A comparison with explosive-source seismic data showed that the synthetic P-wave first-arrival travel times of the new model were closer to the observations than those of the previous velocity *** velocity cross-sections across the source areas of the 2022 Lushan MS6.1 and Ludian MS6.8 earthquakes reveal that the former earthquake occurred near a weak contact zone between the Tibetan Plateau and Sichuan Basin,and the rupture of the latter earthquake occurred in a granitic area,with the northern end blocked by rigid high-velocity bodies.A clear high-velocity anomaly zone is distributed along the western margin of the Yangtze Block,revealing the spatial distribution of Neoproterozoic intermediate-basic *** high-velocity zone significantly controls the morphology of fault zones and influences the rupture processes of major *** northeast-southwest and north-south trending high-velocity anomalies were found near Panzhihua,potentially related to Neoproterozoic and Middle-Late Permian intermediate

关键词： Eastern Tibetan Plateau China Seismic Experimental Site Yangtze Block Velocity model Double-difference tomography

Crustal thickness in southeast Tibet based on the SWChinaCVM-1.0 model

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Earthquake Science 2021年第3期34卷 246-260页

作者： Liyi Chen weilai wang Long Zhang Institute of Geophysics China Earthquake AdministrationBeijing 100081China

Extensive geophysical research has been carried out in southeast Tibet due to the complex geological structure and high *** study of the Moho interface can provide useful information for the geophysical ***-1.0 is the first version of a regional community velocity model for the Sichuan-Yunnan region and aims to provide a reference for seismological research in the *** on this model,a high-precision community Moho interface model can be obtained using common conversion point(CCP)stacking,to further expand the applicability of *** CCP stacking,it is necessary to check the fit of the practical and theoretical travel times of the Ps phase and its multiples under the constraints of the *** this method,referred to as Hκ0 stacking,we determined the Moho ***,the multiples were poorly fitted with the theoretical travel times at many stations,and the crustal thickness obtained was inconsistent with previous ***,we speculate that the SWChinaCVM-1.0 model has some limitations that render it incompatible with the CCP stacking *** further verify this hypothesis,we performed H-κstacking using the v_(P)-v_(S)model,v_(P)model,v_(S)model,and the regional average velocity v_(P0)and compared the results with those of H_(κ0)*** results of the comparison indicate that the SWChinaCVM-1.0 model requires *** addition,by analyzing the SWChinaCVM-1.0 inversion process,we found that the v_(S)model was more reliable than the v_(P)***,we adopted the crustal thickness obtained using H-κstacking based on the v_(S)model as the initial version of a community Moho interface model for the Sichuan-Yunnan region(SWChinaCVM-MOHO-1.0).

关键词： SWChinaCVM-1.0 receiver function H-κstacking crustal thickness velocity ratio

Aftershock sequence relocation of the 2021 M_(S)7.4 Maduo Earthquake, Qinghai, China

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Science China Earth Sciences 2021年第8期64卷 1371-1380页

作者： weilai wang Lihua FANG Jianping WU Hongwei TU Liyi CHEN Guijuan LAI Long ZHANG Institute of Geophysics China Earthquake AdministrationBeijing 100081China Key Laboratory of Earthquake Source Physics China Earthquake AdministrationBeijing 100081China Qinghai Earthquake Agency Xining 810001China

The 2021 Qinghai Maduo M_(S)7.4 earthquake was one of the strongest earthquakes that occurred in the Bayan Har block of the Tibetan Plateau during the past 30 years,which spatially filled in the gap of strong earthquake in the eastern section of the northern block *** this study,the aftershock sequence within 8 days after the mainshock was relocated by double difference *** results show that the total length of the aftershock zone is approximately 170 km;the mainshock epicenter is located in the center of the aftershock zone,indicating a bilateral *** aftershocks are mainly distributed along NWW direction with an overall strike of 285°.The focal depth profiles indicate that the seismogenic fault is nearly vertical and dips to southwest or northeast in different sections,indicating a complex *** is an aftershock gap located to the southeast of the mainshock epicenter with a scale of approximately 20 *** the eastern end of the aftershock zone,horsetaillike branch faults show the terminal effect of a large strike-slip *** is a NW-trending aftershock zone on the north side of the western section,which may be a branch fault triggered by the *** location of the aftershock sequence is close to the eastern section of the Kunlun Mountain Pass-Jiangcuo(KMPJ)*** sequence overlaps well with surface trace of the KMPJ *** speculate that the KMPJ fault is the main seismogenic fault of the M_(S)7.4 Maduo earthquake.

关键词： Maduo earthquake Aftershock sequence Double-difference location Kunlun Mountain Pass-Jiangcuo fault

S-wave velocity structure beneath Changbaishan volcano inferred from receiver function

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Earthquake Science 2009年第4期22卷 409-416页

作者： Jianping Wu Yuehong Ming Lihua Fang weilai wang Institute of Geophysics China Earthquake Administration Beijing 100081 China

The S wave velocity structure in Changbaishan volcanic region was obtained from teleseismic receiver function modeling. The results show that there exist distinct low velocity layers in crust in volcano area. Beneath WQD station near to the Tianchi caldera the low velocity layer at 8 km depth is 20 km thick with the lowest S-wave velocity about 2.2 km/s At EDO station located 50 km north of Tianchi caldera, no obvious crustal low velocity layer is detected. In the volcanic region, the thickness of crustal low velocity layer is greater and the lowest velocity is more obvious with the distance shorter to the caldera. It indicates the existence of the high temperature material or magma reservoir in crust near the Tianchi caldera. The receiver functions and inversion result from different back azimuths at CBS permanent seismic station show that the thickness of near surface low velocity layer and Moho depth change with directions. The near surface low velocity layer is obviously thicker in south direction. The Moho depth shows slight uplifting in the direction of the caldera located. We con- sider that the special near surface velocity structure is the main cause of relatively lower prominent frequency of volcanic earthquake waveforms recorded by CBS station. The slight uplifting of Moho beneath Tianchi caldera indicates there is a material exchanging channel between upper mantle and magma reservoir in crust.

关键词： Changbaishan volcano seismic velocity structure receiver function

S-wave velocity structure in the SE Tibetan plateau

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Earthquake Science 2016年第3期29卷 165-172页

作者： Yan Cai Jianping Wu weilai wang Lihua Fang Liping Fan Institute of Geophysics China Earthquake Administration Key Laboratory of Seismic Observation and Geophysical Imaging Institute of Geophysics China Earthquake Administration

We use observations recorded by 23 permanent and 99 temporary stations in the SE Tibetan plateau to obtain the S-wave velocity structure along two profiles by applying joint inversion with receiver functions and surface waves. The two profiles cross West Yunnan block （WYB）, the Central Yunnan sub-block （CYB）, South China block （SCB）, and Nanpanjiang basin （NPB）. The profile at -25°N shows that the Moho interface in the CYB is deeper than those in the WYB and the NPB, and the topography and Moho depth have clear correspondence. Beneath the Xiaojiang fault zone （XJF）, there exists a crustal low-velocity zone （LYZ）, crossing the XJF and expanding eastward into the SCB. The NPB is shown to be of relatively high velocity. We speculate that the eastward extrusion of the Tibetan plateau may pass through the XJF and affect its eastern region, and is resisted by the rigid NPB, which has high velocity. This may be the main cause of the crustal thickening and uplift of the topography. In the Tengchong volcanic area, the crust is shown to have alternate high- and low-velocity layers, and the upper mantle is shown to be of low velocity. We consider that the magma which exists in the crust is from the upper mantle and that the complex crustal velocity structure is related to magmatic differentiation. Between the Tengchong volcanic area and the XJF, the crustal velocity is relatively high. Combining these observations with other geophysical evi- dence, it is indicated that rock strength is high and defor- mation is weak in this area, which is why the level of seismicity is quite low. The profile at ~ 23~N shows that the variation of the Moho depth is small from the eastern rigid block to the western active block with a wide range of LVZs. We consider that deformation to the south of the SE Tibetan Plateau is weak.

关键词： SE Tibetan plateau Velocity structure Receiver function Joint inversion Tengchong volcano

Seismic phase picking in China Seismic Array using a deep convolutional neuron network

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Earthquake Science 2020年第2期33卷 72-81页

作者： Long Zhang Lihua Fang weilai wang Zuoyong Lv Institute of Geophysics China Earthquake AdministrationBeijing 100081China Guangdong Earthquake Agency Guangzhou 510070China

Seismic phase picking is the preliminary work of earthquake location and body-wave travel time *** picking is considered as the most accurate way to access the arrival times but time *** automatic picking methods were proposed in the past decades,but their precisions are not as high as human experts especially for events with low ratio of signal to noise and later *** the increasing deployment of large seismic array,the existing methods can not meet the requirements of quick and accurate phase *** this study,we applied a phase picking algorithm developed on the base of deep convolutional neuron network(PickNet)to pick seismic phase arrivals in ChinArray-Phase *** comparison of picking error of PickNet and the traditional method shows that PickNet is capable of picking more precise phases and can be applied in a large dense *** raw picked travel-time data shows a large variation deviated from the traveltime *** absolute location residual is a key criteria for travel-time data ***,we proposed a flowchart to determine the accurate location of the single-station earthquake via dense seismic array and phase arrival picked by *** research expands the phase arrival dataset and improves the location accuracy of single-station earthquake.

关键词： Seismic seismic earthquake

Three-dimensional S-wave velocity structure of the crust and upper mantle for the normal fault system beneath the Yinchuan Basin from joint inversion of receiver function and surface wave

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Science China Earth Sciences 2023年第5期66卷 997-1014页

作者： weilai wang Guangyao CAI Guijuan LAI Xianwei ZENG Jingjing BAO Long ZHANG Jun SU Mingfei CHEN Institute of Geophysics China Earthquake AdministrationBeijing100081China Earthquake Agency of Ningxia Hui Autonomous Region Yinchuan750001China Sichuan Earthquake Agency Chengdu610041China

A series of parallel normal faults are distributed in the Helan Mountain-Yinchuan Basin tectonic belt,where a historical M8.0 earthquake *** is rare that such a great earthquake occurs in a normal fault system within the *** deeply understand the fine structure of the normal fault system,we deployed 104 broadband temporary stations near the system,collected data from permanent stations and other temporary stations nearby,and obtained the high-precision threedimensional S-wave velocity structure beneath 206 stations via joint inversion of receiver function and surface wave.A typical graben-in-graben feature bounded by four major faults was identified in the Yinchuan *** analyzed the seismicity in the normal fault system and found a seismic strip in the southern part of the basin,where there are significant changes in the sedimentary thickness,which is speculated to be the southern boundary of the normal fault *** are significant differences in the crustal thickness and velocity structure in the crust on both sides of the boundary between the Helan Mountain and the Yinchuan Basin,and a low-velocity zone was identified in the upper mantle beneath this boundary,which could be related to the fact that the Helan Mountain-Yinchuan Basin tectonic belt is located between the Alxa Block and the Ordos *** M8.0 Yinchuan-Pingluo earthquake occurred at the junction of four major faults in the Yinchuan Basin,which was located in the high-velocity zone near the velocity transition zone at the basin-mountain *** low-velocity zone in the upper mantle beneath this boundary may have promoted the nucleation of this *** on evidence from geological drilling,micro seismicity,the regional stress field,and the velocity models obtained in this study,it is inferred that the eastern piedmont fault zone of the Helan Mountain was the seismogenic fault of the 1739 M8.0 Yinchuan-Pingluo earthquake.

关键词： Yinchuan Basin Helan Mountain Receiver function Surface wave tomography Normal fault system