检索结果-南通市图书馆

3-D velocity structure in the central-eastern part of Qilianshan

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Acta Seismologica Sinica(English Edition) 2004年第3期17卷 272-281页

作者： ZHANG Yuan-sheng(张元生) ZHOU Min-du(周民都) RONG Dai-lu(荣代潞) ZHANG Li-guang(张立光) XU Zhong-qiu(许中秋) Lanzhou Institute of Seismology China Earthquake Administration Lanzhou 730000 China Lanzhou Institute of Seismology China Earthquake Administration Lanzhou 730000 China Lanzhou Institute of Seismology China Earthquake Administration Lanzhou 730000 China Lanzhou Institute of Seismology China Earthquake Administration Lanzhou 730000 China Earthquake Administration of Lanzhou City Lanzhou 730000 China

The 3-D velocity tomography image of the central-eastern part of Qilianshan is obtained by the joint inversion of 3-D velocity structure and focal parameters based on the S-P data of micro-earthquakes recorded by the digital seismic network set up for a Sino-French cooperation program since 1996. The inversed velocity structure does primarily reflect some important features of the deep structure in the region and provide the scientific background for the further study of active tectonic structure and the calculation of earthquake parameters.

关键词： central-eastern Qilianshan micro-earthquake observation 3-D velocity structure focal pa-rameters joint inversion

Recent movement changes of main fault zones in the Sichuan-Yunnan region and their relevance to seismic activity

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Science China Earth Sciences 2016年第6期59卷 1267-1282页

作者： LIU Xia MA Jin DU XueSong ZHU Shuang LI LaYue SUN DongYing First Crustal Monitoring and Application Center China Earthquake Administration State Key Laboratory of earthquake Dynamics Institute of GeologyChina Earthquake Administration

The Wenchuan earthquake occurred near the "triple junction" linking the Bayan Har block, the South China block, and the Sichuan-Yunnan rhombic block, and its influences on the surrounding blocks and the main fault zones in the Sichuan-Yunnan region, i.e., the block boundary zone, cannot be ignored. In this paper, changes of movement and stress of the fault zones before and after a strong earthquake were simulated based on the GPS repetition survey results recently obtained during 1999–2007, 2009–2011, and 2011–2013 with a two-dimensional finite-element contact model and the "block- loading" method. The results show that, before the Wenchuan earthquake, the movement of the Longmenshan fault zone was very slow and its compressive stress accumulated rapidly; after the Wenchuan earthquake, movements toward the E-SSE direction of the Bayan Har, southwestern Yunnan, and rhombic blocks were enhanced, and the dextral and horizontal compressive speeds and annual accumulative compressive stress of the Longmenshan fault zone increased markedly by factors of 4.5, 2.1, and 2.5, respectively. The southern Xianshuihe, Anninghe, Zemuhe, Daliangshan, and lijiang-Xiaojinhe fault zones accumulated compressive stress rapidly, forming enhanced compressive stress zones along a NE strike crossing the central part of the Sichuan-Yunnan region. The tensional movement of the Xianshuihe fault zone was enhanced and the slip movement in the central part of the zone was reversed in a short time. The changes are tightly related to the medium-intensity earthquakes that occurred during the same period in this region, revealing that the spatial migration of seismic activity is related to changes of movement of the blocks.

关键词： Sichuan-Yunnan region Wenchuan earthquake Tectonic block Finite-element analysis Fault

Frequency-dependent attenuation of P and S waves in Yunnan region

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Acta Seismologica Sinica(English Edition) 2005年第6期18卷 632-642,749页

作者：王勤彩刘杰郑斯华陈章立 Institute of Geophysics China Earthquake Administration Beijing 100081 China Institute of Earthquake Science China Earthquake Administration Beijing 100036 ChinaEarthquake Administration of Hebei Province Shijiazhuang 050021 China Institute of earthquake Science China Earthquake Administration Beijing 100036 China

We analyzed digital seismogram data of 5668 earthquakes that occurred in Yunnan region between July of 1999 and December of 2003. Among the 22 seismic stations, six ones, namely Baoshan, Yongsheng, lijiang, Heqing, Yimen, and Luquan, were selected and their attenuations of P and S waves were measured by using the extended coda-normalization method. The six stations were classified into three regions according to their location, that is, Baoshan area, Yongsheng-lijiang-Heqing (YLH) area and Luquan-Yimen (LY) area. The values of QS-1 and QP-1 are expressed as QS-1=0.00867 f-0.86, QP-1=0.01155 f-0.93, QS-1=0.01824 f-0.92, QP-1=0.02288 f-0.92, and QS-1=0.01647 f-0.91, QP-1=0.02826 f-0.97 in Baoshan, YLH, LY areas respectively. The attenuation of YLH, LY are closer to each other, however, Baoshan area is apparently lower. Comparing attenuation in the three areas with other areas of the world using the same method, it is suggested that the attenuations of P and S waves in YLH and LY areas are close to Kanto of Japan, but much higher than southeast of South Korea. The QS-1 and QP-1 in Baoshan area are slightly higher than southeastern South Korea. Furthermore, the results indicate that our QS-1 in Yunnan area is close to others by analyzing the coda attenuation.

关键词： extended coda-normalization method attenuation of P wave attenuation of S wave Yunnan region

Impending HRT wave precursors to the Wenchuan M_s8.0 earthquake and methods of earthquake impending prediction by using HRT wave

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Science China Earth Sciences 2009年第10期52卷 1572-1584页

作者： QIAN FuYe ZHAO BiRu QIAN Wei ZHAO Jian HE ShiGen ZHANG HongKui LI ShiYu LI ShaoKun YAN GuLiang WANG ChengMin SUN ZhenKai ZHANG DongNing LU Jun ZHANG Ping YANG GuoJun SUN JiaLin GUO ChunSheng TANG YuXiong XU JianMing XIA KunTao JU Hang YIN BangHong LI Ming YANG DongSheng QI WeiLuo HE TaiMing GUAN HuaPing ZHAO YuLin Institute of Geophysics China Earthquake AdministrationBeijing 100081China Tianjin Hi-tech Development Co.Ltd Tianjin 300201China Department of Physics University of TorontoL6C1V9Canada College of Disaster Prevention Techniques Yanjiao 065201China earthquake administration of Beijing Municipality Beijing 100080China earthquake administration of Sichuan Province Chengdu 610041China Committee of National Development and Reformation Beijing 100824China Institute of earthquake Science China Earthquake AdministrationBeijing 100036China China earthquake Network Center Beijing 100036China earthquake administration of Yunnan Province Kunming 650041China earthquake administration of Tianjin Municipality Tianjin 300201China earthquake administration of Inner Mongolia Autonomous Region Huhhot 010010China The Gucheng District Bureau Lijiang674100China

We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wenchuan Ms8.0 earthquake, we recorded the HRT wave precursor at the only operating station in Hongge (HG, Δ=465 km) and found that significant impending signal had been recorded at the station in the early morning ( 0―5 am) of 12th of May, 2008. The precursor for this earthquake is consistent with precursors recorded for other strong earthquakes. The measured physical properties (geo-resistivity and telluric-current) show tidal wave period oscillations from several days to several months before the earthquakes and the amplitude of such HT oscillation increases significantly towards the occurrence of an earthquake. These HT and RT waves from the epicenter have a causal relationship with the earthquakes that happened several days later. The arrival time of two RT waves is proportional to the distance from the station to the epicenter. The estimated natural decay of the amplitude is correlated with the natural period (T0) of the earthquake fault, which is proportional to the fault length. From this relationship, we can predict the earthquake magnitude. For magnitude 6―9 earthquakes, the natural period is about 1―6 hours. Such oscillation comes from the epicenter area and they can propagate several thousand kilometers in the Earth's crust. Before a strong earthquake in the shallow crust, the conductive pore fluid will experience major changes before the fault rapture. Such fluid change will emit an oscillation in the pore fluid pressure. This is the mechanism for the HRT wave generation. Since the China earthquake administration funded the HRT wave short-term earth-quake prediction project in 2003, the first record of HRT precursor wave has been recorded from the 2004-12-26 Sumatra Mw9.0 earthquake with the largest epicentre distance Δ=2900 km. Thereafter, we

关键词： Wenchuan Ms8.0 earthquake HRT wave (mechanism) model PS-100 geo-resistivity meter HRT wave precursor precursor consistency feasibility of short-term and impending earthquake prediction

Seismotectonic environment of occurring the February 3, 1996 lijiang M=7.0 earthquake, Yunnan Province

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Acta Seismologica Sinica(English Edition) 2004年第4期17卷 453-463页

作者： HAN Zhu-jun(韩竹军) GUO Shun-min(虢顺民) XIANG Hong-fa(向宏发) ZHANG Jia-sheng(张家声) RAN Yong-kang(冉勇康) Institute of Geology China Earthquake Administration Beijing 100029 China Institute of Geology China Earthquake Administration Beijing 100029 China Institute of Geology China Earthquake Administration Beijing 100029 China Institute of Geology China Earthquake Administration Beijing 100029 China Institute of Geology China Earthquake Administration Beijing 100029 China

lijiang-Daju fault, the seismogenic fault of the 1996 lijiang M=7.0 earthquake, can be divided into lijiang-Yuhu segment in the south and Yuhu-Daju segment in the north. The two segments show clear difference in geological tectonics, but have the similar dynamic features. Both normal dip-slip and sinistral strike-slip coexist on the fault plane. This kind of movement started at the beginning of the Quaternary (2.4~2.5 Ma B.P.). As to the tectonic types, the detachment fault with low angle was developed in the Early Pleistocene and the normal fault with high angle only after the Mid-Pleistocene (0.8 Ma B.P.). Based on the horizontal displacements of gullies and the vertical variance of planation surfaces cross the lijiang-Daju fault at east piedmont of Yulong-Haba range, the average horizontal and vertical slip rates are calculated. They are 0.84 mm/a and 0.70 mm/a since the Quaternary and 1.56 mm/a and 1.69 mm/a since the Mid-Pleistocene. The movements of the nearly N-S-trending lijiang-Daju fault are controlled not only by the regional stress field, but also by the variant movement between the Yulong-Haba range and lijiang basin. The two kinds of dynamic processes form the characteristics of seismotectonic environment of occurring the 1996 lijiang earthquake.

关键词： the 1996 lijiang earthquake variant movement basin boundary fault seismotectonic envi-ronment

Lateral migration of fault activity in Weihe basin

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Acta Seismologica Sinica(English Edition) 2004年第2期17卷 190-199页

作者： FENG Xi-jie(冯希杰) DAI Wang-qiang(戴王强) earthquake administration of Shaanxi Province Xi''an 710068 China Earthquake Administration of Shaanxi Province Xi''an 710068 China

Lateral migration of fault activity in Weihe basin is a popular phenomenon and its characteristics are also typical. Taking the activity migrations of Wangshun Mountain piedmont fault toward Lishan piedmont fault and Weinan platform front fault, Dabaopi-Niujiaojian fault toward Shenyusi-Xiaojiazhai fault, among a serial of NE-trending faults from Baoji city to Jingyang County as examples, their migration time and process are analyzed and discussed in the present paper. It is useful for further understanding the structure development and physiognomy evolution history of Weihe basin.

关键词： lateral migration fault activity Weihe basin

Contemporary crustal tectonic movement in the southern Sichuan-Yunnan block based on dense GPS observation data

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Earth and Planetary Physics 2019年第1期3卷 53-61页

作者： HongLin Jin Yuan Gao XiaoNing Su GuangYu Fu Key Laboratory of earthquake Prediction China Earthquake Administration Institute of earthquake Forecasting China Earthquake Administration

We analyzed 360 permanent and campaign GPS data from 1999 to 2017 in the southern Sichuan-Yunan block, and obtained crustal horizontal deformation in this ***, we derived the strain rate using a multi-scale spherical wavelet *** reveal a complex pattern of tectonic movement in the southern Sichuan-Yunnan *** to the stable Eurasian plate, the maximum rate of the horizontal deformation in the southern Sichuan-Yunnan block is approximately 22 mm/*** Xiaojiang fault shows a significantly lower deformation—a left-lateral strike-slip movement of 9.5 mm/*** Honghe fault clearly shows a complex segmental deformation from the north to *** northern Honghe fault shows 4.3 mm/a right strike-slip with 6.7 mm/a extension; the southern Honghe fault shows 1.9 mm/a right strike-slip with 1.9 mm/a extension; the junction zone in the Honghe and lijiang–Xiaojinhe faults shows an obvious clockwise-rotation *** strain calculation results reveal that the maximum shear-strain rate in this region reaches 70 nstrain/a, concentrated around the Xiaojiang fault and at the junction of the Honghe and lijiang–Xiaojinhe *** note that most of the earthquakes with magnitudes of 4 and above that occurred in this region were within the high shear strain-rate zones and the strain rate gradient boundary zone, which indicates that the magnitude of strain accumulation is closely related to the seismic *** of the fast shear-wave polarization direction of the upper-crust with the upper-mantle anisotropy and the direction of the surface principal compressive strain rate obtained from the inversion of the GPS data reveals that the direction of the surface principal compressive strain is basically consistent with the fast shear-wave polarization direction of the upper crust anisotropy, but different from the polarization direction of the upper *** results support the hypothesis that the principal elements of the deformation mecha

关键词： GPS data crustal horizontal deformation extension strike slip strain rate fast shear-wave polarization

Crustal thicknesses and Poisson's ratios beneath the Chuxiong-Simao Basin in the Southeast Margin of the Tibetan Plateau

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Earth and Planetary Physics 2019年第1期3卷 69-84页

作者： ZiQi Zhang Yuan Gao Key Laboratory of earthquake Prediction Institute of Earthquake ForecastingChina Earthquake Administration Institute of earthquake Forecasting China Earthquake Administration

In the Southeast Margin of the Tibetan Plateau, low-velocity sedimentary layers that would significantly affect the accuracy of the H-κ stacking of receiver functions are widely *** this study, we use teleseismic waveform data of 475 events from 97 temporary broadband seismometers deployed by ChinArray Phase I to obtain crustal thicknesses and Poisson's ratios within the Chuxiong-Simao Basin and adjacent area, employing an improved method in which the receiver functions are processed through a resonance-removal filter, and the H-κ stacking is *** show that the crustal thickness ranges from 30 to 55 km in the study area, reaching its thickest value in the northwest and thinning toward southwest, southeast and *** apparent variation of crustal thickness around the Red River Fault supports the view of southeastern escape of the Tibetan *** thin crustal thickness in the zone between Chuxiong city and the Red River Fault indicates possible uplift of mantle in this *** positive correlation between crustal thickness and Poisson's ratio is likely to be related to lower crust *** of results obtained from different methods shows that the improved method used in our study can effectively remove the reverberation effect of sedimentary layers.

关键词： receiver functions sedimentary layer southeast margin of the Tibetan Plateau crustal thickness Poisson's ratio Chuxiong-Simao Basin

Study on the characteristics of earthquake's impact on cities

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Acta Seismologica Sinica(English Edition) 2004年第2期17卷 222-229页

作者： PAN Hua(潘华) ZHAO Feng-xin(赵凤新) GAO Meng-tan(高孟潭) Institute of Geophysics China Earthquake Administration Beijing 100081 China Institute of Geophysics China Earthquake Administration Beijing 100081 China Institute of Geophysics China Earthquake Administration Beijing 100081 China

Firstly, the impact of historical earthquakes on 34 China province-level capital cities is evaluated by using historical earthquake catalog. The distribution of affected intensity shows, about 53% of cities have even not been affected by earthquake intensity VI, and 44% of cities have been hit by earthquake intensity VII to IX. For most of the cities, occurrence frequency of affected intensity VI is usually higher than that of affected intensity larger than VI, and the value of affected intensity with maximal occurrence frequency may be very different among cities. So both the maximal affected intensity and the affected intensity with maximal occurrence frequency should be taken into account when the prevention seismic intensity needs to be determined. Secondly, considering the incompleteness of records of historical earthquakes, a method of earthquake catalog computer simulation is introduced to study the features of affected intensity of big cities. 69 county-level cities of Fujian Province are selected to be statistical objects. The statistical result shows, for different risk levels the seismic intensity changes greatly among cities, the seismic intensity of 2% probability of exceedance in 50 years can be regarded as the characteristic affected intensity of city, and can be the basis of determining the city special earthquake prevention level and a proper indicator of future earthquakes impact on cities.

关键词： city group affected intensity characteristics earthquake probability of exceedance