2021年阿拉斯加MW8.2地震发生前破裂体积内及其周围区域视应力变化的研究

IF 1.2 4区 地球科学 Q3 Earth and Planetary Sciences
Xuezhong Chen , Yane Li , Lijuan Chen
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引用次数: 1

摘要

2021年7月29日,阿拉斯加半岛南部发生里氏8.2级大地震。为研究地震灾区在此次地震前的地应力时空变化,选取1980年1月至2021年6月发生在震中及周边地区的159次4.7≤MW≤6.9级地震,研究其视应力的时空变化和空间分布。分析了地震活动与地球自转的相关性,探讨了此次地震的发震过程。地应力从2008年1月到2016年12月呈上升趋势。这一时期之后是2017年1月至MW8.2地震发生的亚不稳定阶段。应力增加期前5年的平均表观应力变化率约为后4年的2.3倍。视应力横向分布表明,在孕震过程中,视应力大于1.0 MPa的区域呈扩大趋势。在过去四年中,最大视应力位于地震震中。在东西向垂直剖面上的视应力分布表明,在应力增加期的前5年,震源周围形成了一个视应力间隙,周围有较高的视应力区。阿拉斯加地震后,这个缺口的大部分被余震填补。亚不稳定阶段的地震活动与地球自转有显著的相关性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Investigation on variations of apparent stress in the region in and around the rupture volume preceding the occurrence of the 2021 Alaska MW8.2 earthquake

On July 29, 2021, a large earthquake of MW8.2 occurred south of the Alaska Peninsula. To investigate the spatial-temporal changes of crustal stress in the earthquake-stricken area before this event, we selected 159 earthquakes of 4.7 ≤ MW ≤ 6.9 that occurred in the epicentral region and its surroundings between January 1980 and June 2021 to study the temporal variation and spatial distribution of their apparent stress. In addition, we analyzed the correlation between seismic activities and Earth’s rotation and explored the seismogenic process of this earthquake. The crustal stress rose from January 2008 to December 2016. This period was followed by a sub-instability stage from January 2017 until the occurrence of the MW8.2 earthquake. The average rate of apparent stress change in the first five years of the stress increase period was roughly 2.3 times that in the last four years. The lateral distribution of the apparent stress shows that the areas with apparent stress greater than 1.0 MPa exhibited an expanding trend during the seismogenic process. The maximum apparent stress was located at the earthquake epicenter during the last four years. The distribution of the apparent stress in the E-W vertical cross section revealed that an apparent stress gap formed around the hypocenter during the first five years of the stress increase period, surrounded by areas of relatively high apparent stress. After the Alaska earthquake, most parts of this gap were filled in by aftershocks. The seismic activities during the sub-instability stage exhibited a significant correlation with Earth’s rotation.

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来源期刊
Earthquake Science
Earthquake Science GEOCHEMISTRY & GEOPHYSICS-
CiteScore
1.10
自引率
8.30%
发文量
42
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.
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