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

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

Earthquake Science (Feb 2024)

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

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

Affiliations

Tian Li: SinoProbe Laboratory, School of Earth and Space Sciences, Peking University, Beijing 100871, China; Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards, Peking University, Beijing 100871, China
Lei Zhang: SinoProbe Laboratory, School of Earth and Space Sciences, Peking University, Beijing 100871, China; Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards, Peking University, Beijing 100871, China
Xiaodong Song: SinoProbe Laboratory, School of Earth and Space Sciences, Peking University, Beijing 100871, China; Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards, Peking University, Beijing 100871, China; Corresponding author.
Qincai Wang: Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China; Corresponding author.
Xinyu Jiang: SinoProbe Laboratory, School of Earth and Space Sciences, Peking University, Beijing 100871, China; Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards, Peking University, Beijing 100871, China
Jinchuan Zhang: Earthquake Agency of Jiangsu Province, Nanjing 210014, China
Hanlin Chen: Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China

Journal volume & issue: Vol. 37, no. 1
pp. 51 – 66

Abstract

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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.

Published in Earthquake Science

ISSN: 1674-4519 (Print); 1867-8777 (Online)
Publisher: KeAi Communications Co., Ltd.
Country of publisher: China
LCC subjects: Science: Geology
Website: https://www.keaipublishing.com/en/journals/earthquake-science/

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