Intrinsic and scattering attenuations of the Sichuan-Yunnan region in China from S coda waves

IF 1.2 4区地球科学 Q3 Earth and Planetary Sciences

Earthquake Science Pub Date : 2024-02-01 DOI:10.1016/j.eqs.2023.11.003

Tian Li , Lei Zhang , Xiaodong Song , Qincai Wang , Xinyu Jiang , Jinchuan Zhang , Hanlin Chen

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引用次数: 0

Abstract

Seismic attenuation is a fundamental property of the Earth's media. Attenuation structure for the complicated geological structures with strong seismicity in the Sichuan-Yunnan region is poorly studied. In this study, we collected 108,399 waveforms of 11,517 local small earthquakes with magnitudes between 1.5 and 3.5 from January 2014 to September 2021 in the Sichuan-Yunnan region and its adjacent areas. We employed an envelope inversion technique for separating the intrinsic and scattering attenuations of the S coda wave, and obtained the intrinsic and scattering attenuation structures for frequencies between 0.25 and 8.00 Hz. The attenuation structures correlate well with the geological units, and some major faults mark the attenuation variations where historic large earthquakes have occurred. The regional average attenuation shows a negative frequency dependence. The average scattering attenuation has a faster descending rate than the average intrinsic attenuation, and is dominant at low frequencies, while at high frequencies the average intrinsic attenuation is stronger. The lateral variation in the intrinsic attenuation is consistent with the variation in heat flow, the scattering attenuation may be related to the scatter distribution and size. The total attenuation is consistent with the previous studies in this region, and the separate intrinsic and scattering attenuation may be useful in understanding regional tectonics and important in earthquake prevention and disaster reduction.

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中国四川-云南地区 S 尾波的本征和散射衰减

地震衰减是地球介质的基本特性。目前对四川云南地区强震复杂地质结构的衰减结构研究较少。本研究收集了 2014 年 1 月至 2021 年 9 月川滇地区及其邻近地区发生的 11,517 次 1.5 级至 3.5 级局部小地震的 108,399 个波形。我们采用包络反演技术分离了 S 尾振波的本征衰减和散射衰减，得到了频率在 0.25 至 8.00 Hz 之间的本征衰减结构和散射衰减结构。衰减结构与地质单元有很好的相关性，历史上发生过大地震的一些主要断层标志着衰减变化。区域平均衰减与频率呈负相关。平均散射衰减的下降速度比平均本征衰减快，在低频时占主导地位，而在高频时平均本征衰减较强。本征衰减的横向变化与热流的变化一致，散射衰减可能与散射分布和大小有关。总衰减与该地区以往的研究结果一致，单独的本征衰减和散射衰减可能有助于了解区域构造，对防震减灾具有重要意义。

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来源期刊

Earthquake Science GEOCHEMISTRY & GEOPHYSICS-

CiteScore

1.10

自引率

8.30%

发文量

审稿时长

3 months

期刊介绍： Earthquake Science (EQS) aims to publish high-quality, original, peer-reviewed articles on earthquake-related research subjects. It is an English international journal sponsored by the Seismological Society of China and the Institute of Geophysics, China Earthquake Administration. The topics include, but not limited to, the following ● Seismic sources of all kinds. ● Earth structure at all scales. ● Seismotectonics. ● New methods and theoretical seismology. ● Strong ground motion. ● Seismic phenomena of all kinds. ● Seismic hazards, earthquake forecasting and prediction. ● Seismic instrumentation. ● Significant recent or past seismic events. ● Documentation of recent seismic events or important observations. ● Descriptions of field deployments, new methods, and available software tools. The types of manuscripts include the following. There is no length requirement, except for the Short Notes. 【Articles】 Original contributions that have not been published elsewhere. 【Short Notes】 Short papers of recent events or topics that warrant rapid peer reviews and publications. Limited to 4 publication pages. 【Rapid Communications】 Significant contributions that warrant rapid peer reviews and publications. 【Review Articles】Review articles are by invitation only. Please contact the editorial office and editors for possible proposals. 【Toolboxes】 Descriptions of novel numerical methods and associated computer codes. 【Data Products】 Documentation of datasets of various kinds that are interested to the community and available for open access (field data, processed data, synthetic data, or models). 【Opinions】Views on important topics and future directions in earthquake science. 【Comments and Replies】Commentaries on a recently published EQS paper is welcome. The authors of the paper commented will be invited to reply. Both the Comment and the Reply are subject to peer review.