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飑线天气过程对云南洞体应变干扰的特征与机制

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地球物理学进展 2024年第2期39卷 480-489页

作者：杨小林危自根王军井冈山大学吉安343009 中国科学院精密测量科学与技术创新研究院武汉430077 云南省地震局昆明650224

2016年4月19日云南地区爆发了一次强飑线天气,并相继对楚雄和昆明台的洞体应变观测产生了显著干扰.那么其扰动的全貌和机制究竟如何?截止目前,还鲜有研究.有鉴于此,本文结合多普勒天气雷达和地面气象观测要素数据,对楚雄和昆明台洞体应... 详细信息

2016年4月19日云南地区爆发了一次强飑线天气,并相继对楚雄和昆明台的洞体应变观测产生了显著干扰.那么其扰动的全貌和机制究竟如何?截止目前,还鲜有研究.有鉴于此,本文结合多普勒天气雷达和地面气象观测要素数据,对楚雄和昆明台洞体应变的响应历程进行了深入分析.结果表明:(1)飑线过境时的“雷暴鼻”是洞体应变呈脉冲状张性变化的主因,由此产生的最大应变量为19.04×10^(-9);(2)各台洞体应变的扰动形态与“雷暴鼻”高度相似,说明其台基岩体均能以线弹性变形的方式响应飑线过程中的气压剧变;(3)“雷暴鼻”中周期性气压的能量主要集中在8~20 cpd频段内;(4)洞体应变对“雷暴鼻”的响应存在一定的相位超前现象.以上结果,不单有助于辨识云南地区洞体应变时序曲线中飑线噪声,而且还能为高频段气压效应的精确改正等提供观测证据.

关键词：云南飑线洞体应变气压迁移地壳形变

利用HVSR方法探测四川理县西山村滑坡速度结构

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地球物理学报 2024年第4期67卷 1515-1526页

作者：孙晓倩储日升曾求盛敏汉危自根中国科学院精密测量科学与技术创新研究院大地测量与地球动力学国家重点实验室武汉430077 中国科学院大学地球与行星科学学院北京100049 湖北省地质局地球物理勘探大队武汉430056

HVSR(Horizontal-to-Vertical Spectral Ratio)是地震背景噪声水平分量与垂直分量的频谱比,常被用来探测起伏地形较小的浅地表速度结构.然而,高起伏地形下该方法的适用性还需要仔细研究.本文探讨利用HVSR方法探测四川理县西山村滑坡的... 详细信息

HVSR(Horizontal-to-Vertical Spectral Ratio)是地震背景噪声水平分量与垂直分量的频谱比,常被用来探测起伏地形较小的浅地表速度结构.然而,高起伏地形下该方法的适用性还需要仔细研究.本文探讨利用HVSR方法探测四川理县西山村滑坡的速度结构.我们首先将ENZ坐标系下三分量地震数据旋转到垂直于地形自由面的LQT坐标系,分别计算了两个坐标系下2 h地震背景噪声数据的HVSR曲线,对比结果发现,LQT坐标系下三分量数据的HVSR峰值频率更能反映地下结构信息.然后,本文反演了29个台站LQT坐标系的HVSR曲线,获得了滑坡体堆积物及基岩的一维S波速度结构.西山村滑坡体堆积物的S波速度范围为50~1000 m·s^(-1),滑坡厚度23~130 m.滑坡体西侧边缘地下40~120 m处存在10~20 m的低速层,表明该位置抗剪强度相对较弱,是潜在的滑动危险区域.对数据进行坐标系转换后,HVSR方法能够利用较短的观测数据获取可靠的滑坡体速度结构,为滑坡体积估算、脆弱位置识别、灾害评估提供重要信息.

关键词：理县西山村滑坡 HVSR S波速度结构地震背景噪声

Poisson's ratios and S-wave velocities of the Xishancun landslide,Sichuan,China,inferred from high-frequency receiver functions of local earthquakes

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Science China Earth Sciences 2021年第7期64卷 1195-1206页

作者： zigen wei Risheng CHU Zhiwei LI Minhan SHENG Qiu ZENG Slate Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China Science and Technology on Reliability and Environmental Engineering Laboratory Beijing Institute of Spacecraft Environment EngineeringBeijing 100094China

Landslides are recurrent geological phenomena on Earth that cause heavy casualties and property losses *** this study,we use the V_(p)-k stacking and nonlinear waveform inversion methods of high-frequency receiver functions extracted from local earthquakes,to sequentially invert Poisson’s ratios and S-wave velocities of the Quaternary Xishancun landslide,which is composed of three segments,i.e.,h1,h2,and h3 from bottom to *** results show that Poisson’s ratio values are generally higher than 0.33 and that the S-wave velocities vary from 0.1 to 0.9 km s^(-1).High Poisson’s ratios(>0.44)are mainly distributed in the juncture regions between different segments,as well as the western edge of *** zones show significant variation in landslide thickness and are potentially hazardous *** velocities of 0.05–0.2 km s^(-1)with thicknesses of 10–30m are widely observed in the lower layer of the *** high Poisson’s ratios and low-velocity layer may be related to water-rich materials in these *** study suggests that the high-frequency receiver functions from local earthquakes can be used to delineate geotechnical structures,which is valuable for landslide stability analysis and hazard mitigation.

关键词： Xishancun landslide High-frequency receiver functions High Poisson's ratio Low S-wave velocity Landslide stability and hazard mitigation

Crustal S-velocity structure and radial anisotropy beneath the southern part of central and western North China Craton and the adjacent Qilian Orogenic Belt from ambient noise tomography

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Science China Earth Sciences 2017年第10期60卷 1752-1768页

作者： LING Yuan CHEN Ling wei zigen JIANG MingMing WANG Xu State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China College of Earth Sciences University of Chinese Academy of Sciences Beijing 100049 CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101 China State Key Laboratory of Geodesy and Earth's Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of the Earth and Planetary Physics Chinese Academy of Sciences Beijing 100029 China

The crustal S-velocity structure and radial anisotropy along a dense linear portable seismic array with 64 broadband seismic stations were investigated from ambient noise tomography with about one-year-long ambient noise recordings. The array transverses the southern part of the central North China Craton(CNCC) and western NCC(WNCC) from east to west and reaches the adjacent Qilian Orogenic Belt(QOB). The phase velocity structures of Rayleigh waves at 5–35 s and Love waves at 5–30 s were measured. The crustal S-velocity structures(Vsv and Vsh) were constructed from the dispersion data(Rayleigh and Love waves,respectively) from point-wise linear inversion with prior information of the Moho depth and average crustal Vp/Vs ratio. The radial anisotropy along the profile was calculated based on the discrepancies between Vsv and Vsh as 2×(***)/(Vsh+Vsv). The results show distinct structural variations in the three major tectonic units. The crustal architecture in the southern CNCC is complicated and featured with wide-distributed low-velocity zones(LVZs), which may be a reflection of crustal modification resulting from Mesozoic-Cenozoic tectonics and magmatic activities. The pronounced positive radial anisotropy in the lower-lowermost crust beneath the Shanxi-Shaanxi Rift and the neighboring areas could be attributed to the underplating of mantle mafic-ultramafic materials during the Mesozoic-Cenozoic tectonic activation. In southern Ordos, the overall weak lateral velocity variations, relative high velocity and large-scale positive radial anisotropy in mid-lower crust probably suggest that the current crustal structure has preserved its Precambrian tectonic characteristics. The low-velocity westward-dipping sedimentary strata in the Ordos Block could be attributed to the Phanerozoic whole-basin tilting and the uneven erosion since late Cretaceous. Integrated with previous studies, the systematic comparison of crustal architecture was made between the southern and nor

关键词： North China Craton Qilian Orogenic Belt Ambient noise tomography Crustal S-velocity structure Radial anisotropy

利用地震背景噪声自相关探测四川理县西山村滑坡结构

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地球物理学报 2024年第10期67卷 3735-3746页

作者：孙晓倩储日升曾求谢军盛敏汉危自根莫丽桦中国科学院精密测量科学与技术创新研究院大地测量与地球动力学国家重点实验室武汉430077 中国科学院大学地球与行星科学学院北京100049 湖北省地质局地球物理勘探大队武汉430056

地震背景噪声自相关法不需要人工震源或天然地震即可获得地下速度界面的反射响应,广泛应用于不同尺度的结构探测中.然而,由于多数土质滑坡体的厚度介于数米至百米之间且结构复杂,尽管其风化层和底部基岩界面上下的物性存在显著不同,地... 详细信息

地震背景噪声自相关法不需要人工震源或天然地震即可获得地下速度界面的反射响应,广泛应用于不同尺度的结构探测中.然而,由于多数土质滑坡体的厚度介于数米至百米之间且结构复杂,尽管其风化层和底部基岩界面上下的物性存在显著不同,地震背景噪声自相关方法在探测滑坡体结构的应用研究并不常见.为此,我们以四川理县西山村滑坡为例,尝试利用水平分量地震背景噪声自相关方法探测该滑坡体结构.首先,我们将连续噪声数据截取为长3600 s的时窗,再对每段数据进行时域归一化和谱白化,接着计算自相关函数并带通滤波到1~15 Hz,最终提取了台站下方滑坡体与基岩分界面的一次及多次反射S波响应.结果表明,西山村滑坡上22个台站的E分量自相关函数提取到的界面反射S波双程走时介于0.14~0.25 s,获得的滑坡体厚度为57~102 m.因为西山村滑坡体较薄,P波在自由地表和地下界面之间的双程走时小于0.1 s,导致P波反射响应无法从自相关函数的本征值中分辨出来.本研究对西山村滑坡部分台站的沉积层厚度进行了补充,结果表明西山村滑坡第四系沉积物呈北厚南薄的特征,且综合电法剖面与接收函数结果,滑坡内部100 m深度范围内有大面积低电阻率特征、高泊松比的含水层,抗滑能力差,若有降雨与地震的影响,北部的碎石堆积物容易脱落,对南部村落聚集地造成较大损失.

关键词：背景噪声自相关 S波反射理县西山村滑坡滑动面埋深

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Determination of the crustal structure and seismicity of the Linfen rift with S-wave velocity mapping

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Frontiers of Earth Science 2020年第3期14卷 647-659页

作者： zigen wei Risheng Chu Meiqin Song Xiaolin Yang Shanshan Wu Feng Bao State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430077China Earthquake Administration of Shanxi Province Taiyuan030021China Shaanxi Earthquake Agency Xi’an710068China Shanghai Earthquake Agency Shanghai200062China

The Linfen rift is a Cenozoic extensional rift with significant seismicity and seismic *** of this rift shed light on deep dynamic processes and seismogenic mechanisms relevant to crustal structure and seismic *** first conducted a joint inversion of receiver functions and surface wave dispersion on waveform data collected from 27 broadband seismic stations to image the crustal S-wave velocity in the Linfen rift and its *** then relocated the source parameters for 10 earthquake events with depths>20 km and studied the relationship between crustal S-wave velocity and *** results show that low-velocity zones of different scales exist in the middle-lower crust,and that the depth of the seismogenic layer gradually increases from^25 km in the south to^34 km in the north,roughly corresponding to the bottom of the low-velocity *** found that most of the relocated earthquakes occurred in the low-velocity zone at depths of 18 km to 34 km,with the deepest at 32 *** of the greatest historic earthquakes,Linfen(Ms 7.75)in 1695 and Hongtong(Ms 8.0)in 1303,occurred at the bottom of the high-velocity zone at depths of 12 km to 18 *** results,combined with previous studies,suggest that the upwelling mantle material below the rift did not remarkably affect the velocity structure from the bottom of the seismogenic layer down to the uppermost mantle nor heat the *** is likely that neither crustal-scale faults nor mantle earthquakes exist in the Linfen rift.

关键词： Linfen rift joint inversion S-wave velocity seismogenic layer deep crustal earthquake

Crustal thickness,V_(P)/V_(S) ratio,and shear wave velocity structures beneath Myanmar and their tectonic implications

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Earthquake Research Advances 2022年第1期2卷 15-21页

作者： Lay Nwe zigen wei Zhiwei Li Feng Bao Xuelei Li Jintao Hu State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430077China Science and Technology on Reliability and Environmental Engineering Laboratory Beijing Institute of Spacecraft Environment EngineeringBeijing100094China School of Science Hunan University of Technology and BusinessChangsha410205China Department of Meteorology and Hydrology Ministry of Transport and CommunicationsMyanmar Hebei University of Engineering Handan056009China

The crustal structure in Myanmar can provide valuable information for the eastern margin of the ongoing IndoEurasian collision *** successively performed H-k stacking of the receiver function and joint inversion of the receiver function and surface wave dispersion to invert the crustal thickness(H),shear wave velocity(V_(S)),and the V_(P)/V_(S) ratio(k)beneath nine permanent seismic stations in Myanmar.H was found to increase from 26 km in the south and east of the study area to 51 km in the north and west,and the V_(P)/V_(S) ratio was complex and *** differences in the crust were observed for different tectonic *** the Indo-Burma Range,the thick crust(H~51 km)and lower velocities may be related to the accretionary wedge from the Indian *** the Central Myanmar Basin,the thin crust(H=26.9-35.5 km)and complex V_(P)/V_(S) ratio and V_(S) suggest extensional *** the Eastern Shan Plateau,the relatively thick crust and normal V_(P)/V_(S) ratio are consistent with its location along the western edge of the rigid Sunda Block.

关键词： Myanmar Crustal thickness VP/VSratio Shear wave velocity Receiver function Surface wave dispersion

Regional differences in crustal structure of the North China Craton from receiver functions

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Science China Earth Sciences 2015年第10期58卷 2200-2210页

作者： wei zigen CHU RiSheng CHEN Ling State Key Laboratory of Geodesy and Earth's Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences

Moho depth and crustal average Poisson＇s ratio for 823 stations are obtained by H-n： stacking of receiver functions. These, to- gether with topography and receiver function amplitude information, were used to study the crustal structure beneath the North China Craton （NCC）. The results suggest that modified and preserved crust coexist beneath the craton with generally Airy-type isostatic equilibrium. The equilibrium is relatively low in the eastern NCC and some local areas in the central and western NCC, which correlates well with regional geology and tectonic features. Major differences in the crust were observed beneath the eastern, central, and western NCC, with average Moho depths of 33, 37, and 42 km and average Poisson＇s ratios of 0.268, 0.267 and 0.264, respectively. Abnormal Moho depths and Poisson＇s ratios are mainly present in the rift zones, the northern and southern edges of the central NCC, and tectonic boundaries. The crust beneath Ordos retains the characteristics of typical craton. Poisson＇s ratio increases roughly linearly as Moho depth decreases in all three parts of the NCC with different slopes. Receiver function amplitudes are relatively large in the northern edge of the eastern and central NCC, and small in and near the rifts. The Yanshan Mountains and southern part of the Shanxi rift show small-scale variations in the receiver-function ampli- tudes. These observations suggest that overall modification and thinning in the crust occurred in the eastern NCC, and local crustal modification occurred in the central and westem NCC. Different crustal structures in the eastern, central, and western NCC suggest different modification processes and mechanisms. The overall destruction of the crustal structure in the eastern NCC is probably due to the westward subduction of the Pacific Plate during the Meso-Cenozoic time; the local modifications of the crust in the central and western NCC may be due to repeated reactivations at zones with a heterogeneous s

关键词： North China Craton Moho depth Poisson's ratio gravitational equilibrium receiver function amplitude regional difference in crust

Regional variations in crustal thickness and Vp/Vs ratio beneath the central-western North China Craton and adjacent regions

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Regional variations in crustal thickness and Vp/Vs ratio ben...