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Study on the applicability of frequency spectrum of micro-tremor and dynamic characteristics of surface ground in Asia area

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1856-1863页

作者： CHE Ai-lan IWATATE Takahiro ODA Yoshiya GE Xiu-run School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200030 China Department of Civil and Environmental Engineering To~o Metropolitan University Tokyo 192-0397 Japan Department of Civil Engineering Xi ＇an Jiaotong Universitv Xi ＇an 710049. China

The dynamic characteristics of ground soil using micro-tremor observation in Asia (Zushi and Ogasawara (Japan), Xi’an (China), Manila (Philippines), and Gujarat (India)) are studied. Ground micro-tremor signals were observed and analyzed by fast Fourier transform method (FFT). The response of ground soil to frequency of ground micro-tremor is revealed, and func- tions with frequency-dependence and frequency-selection of micro-tremor for different foundation soil strata are also researched. The horizontal to vertical spectral ratio (H/V, Nakamura technique) of micro-tremor observed at the surface ground was used to evaluate the site’s predominant period. This paper also discusses the application of micro-tremor on site safety evaluation, and gives the observed calculation results obtained at multiple points. The experimental foundation and the deduction process of the method are described in detail. Some problems of the method are pointed out. Potential use of the technique’s good expandable nature makes it a useable means for preventing and reducing disaster’s harmful effects.

关键词： Micro-tremor observation Nakamura method predominant period Earthquake observation Spectral analysis

Application of active-source surface waves in urban underground space detection: A case study of Rongcheng County, Hebei, China

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Earth and Planetary Physics 2022年第4期6卷 385-398页

作者： GuangWen Wang HaiYan Wang HongQiang Li ZhanWu Lu WenHui Li TaiRan Xu Lithosphere Center Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Deep-Earth Dynamics Key Laboratory of the Ministry of Natural Resources Beijing 100037China Chinese Academy of Geological Sciences Beijing 100037China China Earthquake Network Center Beijing 100045China

Active-source surface wave exploration is advantageous because it has high imaging accuracy,is not affected by high-speed layers,and has a low cost;thus,it has unique advantages for investigating shallow surface *** the development and utilization of urban underground space,two parameters in the shallow surface are important,namely,the shear wave velocity(V_(S))and the predominant period of the site,which determine the elevation and aseismic grade of the building *** traditional method is mainly to obtain the two above-mentioned parameters through testing and measuring drilling ***,this method is extremely expensive and time ***,in this research,we used the multichannel surface wave acquisition method to extract the fundamental dispersion curve of single-shot data by using the phase shift method and obtain the V_(S) characteristics in the uppermost 40 m by *** arrived at the following two conclusions based on the V_(S) ***,the study area can be roughly divided into five layers,among which the layers 0−8 m,14−20 m,and 20−30 m are low-velocity layers,corresponding to miscellaneous fill,a water-bearing sand layer,and a sand layer;therefore,the V_(S) is relatively *** contrast,the layers at 8−14 m and 30−40 m are high-velocity layers that are mainly composed of clay,with a relatively better compactness and relatively high V_(S) *** addition,a low-speed anomaly appears abruptly in the high-speed area at 20−40 *** anomaly,when combined with geological data,suggests that it is an ancient river ***,from the V_(S) value,the V_(Se)(equivalent shear wave velocity)was *** construction site soil was categorized as class III,with good conditions for engineering *** addition,we calculated the predominant period of the site to be 0.56-0.77 s based on the V_(S).Therefore,in the overall structural design of the foundation engineering,the natural vibration period of the structure

关键词： Jizhong depression surface wave exploration shallow structure site category predominant period

Site dependence of far-source ground motions during the Wenchuan earthquake

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Earthquake Science 2009年第5期22卷 531-537页

作者： Longjun Xu Haiying Yu Wenhai Cao Lili Xie Research Center of Civil Engineering Disasters and Prevention Harbin Institute of Technology at Weihai Weihai 264209 China Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China Earthquake Administration of Weihai City Weihai 264209 China

This paper aimed to examine the site dependence and evaluate the methods for site analysis of far-source ground motions. This was achieved through the examination of frequency content estimated by different methods based on strong ground motions recorded at twelve far-source stations in Shandong province during the Wenchuan earthquake. The stations were located in sites with soil profiles ranging from code classes Ⅰ to Ⅲ. Approaches used included the Fourier amplitude spectrum （FAS）, the earthquake response spectrum （ERS）, the spectral ratio between the horizontal and the vertical components （H/V）, the spectral ratio between the spectra at the site and at a reference site （SRRS）, and coda wave analysis （CWA）. Results showed that major periods of these ground motions obtained by FAS, ERS and H/V ratio methods were all evidently larger than site dominant periods; the periods were also different from each other and mainly reflected the frequency content of long period components. Prominent periods obtained by the SRRS approach neither illuminated the long period aspect nor efficiently determined site features of the motions. The CWA resulted in a period close to site period for stations with good quality recordings. The results obtained in this study will be useful for the evaluation of far-source effect in constructing seismic design spectra and in selecting methods for ground motion site analysis.

关键词： Wenchuan earthquake far-source long period ground motion predominant period source effect site condition

Pulse-like ground motion observed during the 6 February 2023 M_(W)7.8 Pazarcık Earthquake(Kahramanmaraş,SE Türkiye)

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地震学报:英文版 2023年第4期36卷 328-339页

作者： Fan Wu Junju Xie Zhao An Chenghao Lyu Tuncay Taymaz Tahir Serkan Irmak Xiaojun Li Zengping Wen Baofeng Zhou Institute of Geophysics China Earthquake AdministrationBeijing 100081China School of Earth and Space Sciences Peking UniversityBeijing 100871China Department of Geophysical Engineering The Faculty of Minesİstanbul Technical UniversityMaslak 34467SarıyerİstanbulTürkiye Department of Geophysical Engineering Kocaeli UniversityUmuttepe 41380KocaeliTürkiye College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China

In this study,we analyzed 100 three-component strong ground motion records observed within 200 km of the causative fault of the 6 February 2023 M_(W)7.8 Pazarcık(Kahramanmaraş)Earthquake in SE Tü*** wavelet method was utilized to identify and analyze the characteristics of pulse-like ground motions in the near-fault region,while considering the uncertainty of the pulse orientation during the *** investigation focused on the effects of the focal mechanism and rupture process on the spatial distribution,pulse orientation,and maximum pulse direction of the observed pulse-like ground *** also analyzed the amplitude and period of the observed ground pulses and the effect of long-period amplification on the ground motion response *** results indicated the following:(1)A total of 21 typical ground velocity pulses were observed during this earthquake,exhibiting complex characteristics due to the influence of the strike-slip mechanism and rupture *** ground pulses(17 out of 21)were recorded within 20 km of the fault,in a wide range of orientations,including normal and parallel to the fault *** waveforms exhibited unidirectional features,indicating the effects of left-lateral fault *** pulses observed more than 20 km from the fault were mainly oriented normal to the *** waveforms were bidirectional with double-or multi-round trips as a result of rupture directivity.(2)The amplitudes of the observed pulses ranged from 30.5 to 220.0 cm/s,with the largest peak velocity of 220.0 cm/s observed at Station *** pulse periods ranged from 2.3 to 14.5 s,with the longest pulse period of 14.5 s observed at Station *** amplitude and period of the pulses observed during this earthquake were comparable to those of similar-magnitude global *** amplitude of the pulses decreased significantly with increasing fault distance,whereas the pulse period was not significantly affected by the fault distance.(3)Com

关键词： 2023 M_(W)7.8 Pazarcık Earthquake pulse-like ground motion response spectrum predominant period