Estimation of Site Effects and Equivalent Source Parameters of Wenchuan Earthquake Based on Generalized Chaotic Particle Inversion Technique
Estimation of Site Effects and Equivalent Source Parameters of Wenchuan Earthquake Based on Generalized Chaotic Particle Inversion Technique
复制标题
DOI：
10.1785/0220230028
复制
发表时间：
2023-11
影响因子：
3.3
通讯作者：
Ke-Lin Chen;Xue-Liang Chen;Jingyan Lan;Li-Jun Qiu;Yi-Ling Zhu
中科院分区：
文献类型：
--
作者：
Ke-Lin Chen;Xue-Liang Chen;Jingyan Lan;Li-Jun Qiu;Yi-Ling Zhu
基于混沌粒子群优化算法和广义逆技术的优点，对汶川地震的震源参数和场地效应进行了估计。我们利用43次余震的440组强震记录，将记录所覆盖的区域划分为A和B两个亚区。首先利用广义反演技术从A、B子区的地震谱中分离震源、路径和场地，然后利用混沌粒子群技术建立震源-场地优化模型。从路径校正记录中，我们得到了33个台站的绝对场地效应和43个地震的等效震源参数。得出以下结论：（1）矩震级Mw小于中国地震台网中心测定的局地震级ML。汶川地震的自相似性得到了证实。应力降平均为2.31MPa，与震级大小和震源深度无关。(2)在频率1-10 Hz中，子区域A和B中的品质因数值为110.9 f0.6和116.1 f1.2。川西高原西部地区地壳介质的衰减速率明显高于东部地区。(3)基岩站51 MXT和L2007在一定频率范围内存在场地效应。坡面地形对场地优势频率的影响不明显，随着海拔的升高，场地效应增强。场地放大率曲线的形状在中、低频段较为相似，在高频段会出现不同的衰减现象。
Based on the advantages of the chaos particle swarm optimization algorithm and the generalized inversion technology, this article estimates the source parameters and site effects of the Wenchuan earthquake. We used 440 sets of strong-motion records obtained from 43 aftershocks, and the area covered by the records was divided into subregions A and B. Initial separation of source, path, and site from the seismic spectra of subregions A and B using generalized inversion technique and then the source-site optimization model is established using chaotic particle swarm technology. From path-corrected records, we obtained absolute site effects for 33 stations and equivalent source parameters for 43 earthquakes. We made the following conclusions: (1) The moment magnitude Mw was lower than the local magnitude MLdetermined by China Earthquake Network Center. The self-similarity of the Wenchuan earthquake was confirmed. The stress drop averaged 2.31 MPa, and it was independent of the magnitude size and focal depth. (2) In the frequency 1–10 Hz, the quality factor values in subregions A and B are 110.9f0.6 and 116.1f1.2. The decay rate of the crustal medium in the western region of the west Sichuan plateau is significant compared to the eastern part. (3) Bedrock stations 51MXT and L2007 have site effects within a certain frequency. The effect of slope topography on site predominant frequency is not apparent, and the site effects increase with the increase in elevation. The shape of the site amplification curve is more similar in the middle- and low-frequency bands, and different attenuation phenomena will appear in the high-frequency band.