摘要
2010年4月14日青海省玉树藏族自治州玉树县发生M7.1地震。震后在地震现场架设了7台强震动流动观测仪,记录了大量强震动记录。本文收集整理了该次流动观测所获得的强震动记录,对典型记录进行了初步处理,并对记录特点和相关问题进行了分析与讨论。
The Yushu M7.1 earthquake occurred on April 14,2010 in Yushu,the Tibetan autono- mous prefecture of the Qinghai province （E 96.7°, N 33. 1°）. After the earthquake,we set up seven strong motion mobile observation instruments around the epicenter. As of October 15, 2010, we had captured 71 seismic events and a total of 213 acceleration records, with the maximum magnitude of M4.6. In these records,there were 10 records whose peak ground acceleration was greater than 30 gal,and the maximum peak ground acceleration was 122 gal. The waveform of re- cords was clear and complete, which makes up for the lack of fixed stations and local records near the earthquake zone. It not only offered the quantitative evidence for analysis of the earthquake damage, but also provided important data for the study of the relationship among the peak ground motion,holding time, the spectrum, and macro-seismic intensity. In this paper, we collected and preliminarily processed these records and obtained the speed schedule, Fourier spectrum, and the power spectrum, then analyzed and discussed the recording features and related issues. The results showed that （1）the maximum peak ground acceleration in this mobile observation was 122 gal, and the holding time of vibration was about 5 seconds, with a frequency of 7.2 Hz. This record came from a M3.6 aftershoek, and it indicated that a small earthquake may also obtain high peak acceleration. This would appear to be the opposite phenomenon of a high vibration peak with low seismic intensity. In fact, there were many major projects located in the area which had small seismicity background. With the increasing coverage of observation stations, this opposite phe- nomenon would become more apparent. We argue, therefore, that the study of this phenomenon should be conducted. （2） In the M4.6 aftershock,the maximum peak ground acceleration was 35.5 gal,and the holding time of the vibration was about 6 seconds,with a frequency of 4.0 Hz. With the expansion of the epicentral distance, the peak ground acceleration of each mobile station grad- ually decreased. But by the effect of the anisotropic medium and site conditions, the same epicen- tral distance {or essentially the same epicentral distance）at different locations may experience un- equal peak ground acceleration. （3）The factors that determined or influenced the severity of the earthquake damage were complex and diverse, and included the acceleration intensity, spectral dis- tribution, site conditions, and structure type, among other factors. Strong ground motion records truly reflected the intensity distribution of the seismic elastic wave in the propagation space. Al- though the relationship between strong motion records and the degree of structural damage was not a simple linear correlation,it may be very necessary to use appropriate methods to establish an appropriate model of the relationship between the ground motion parameters and the degree of damage for the typical building, which could be widely used in rapid damage assessment, intensity quick reports,and other emergency work. In this paper, these analyses and the discussion of the results are preliminary, pending further study after accumulating data supplements.
出处
《地震工程学报》
CSCD
北大核心
2014年第2期274-280,共7页
China Earthquake Engineering Journal
基金
兰州地球物理国家野外科学观测研究站开放基金(2013Y04)
关键词
玉树M7
1地震
流动观测
强震动记录
数据处理
Yushu MT. 1 earthquake
mobile observation
strong motion records
data processing
