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地震 ›› 2024, Vol. 44 ›› Issue (4): 1-13.doi: 10.12196/j.issn.1000-3274.2024.04.001

• •    下一篇

川滇地区中小地震应力降特征及趋势分析

郑现1, 赵翠萍1, 吴微微2, 杨晶琼3   

  1. 1.中国地震局地震预测研究所, 北京 100036;
    2.四川省地震局, 四川 成都 610044;
    3.云南省地震局, 云南 昆明 650216
  • 收稿日期:2024-04-15 修回日期:2024-06-28 出版日期:2024-10-31 发布日期:2024-12-16
  • 通讯作者: 赵翠萍, 研究员。 E-mail:zhaocp@ief.ac.cn
  • 作者简介:郑现(1987-), 女, 吉林长春人, 副研究员, 主要从事地震波层析成像研究。
  • 基金资助:
    国家重点研发计划项目(2021YFC3000703-07)

Characteristics and Trend Analysis of Stress Drop in Small and Moderate Earthquakes in the Sichuan-Yunnan Region

ZHENG Xian1, ZHAO Cui-ping1, WU Wei-wei2, YANG Jing-qiong3   

  1. 1. Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China;
    2. Sichuan Earthquake Agency, Chengdu 610044, China;
    3. Yunnan Earthquake Agency, Kunming 650216, China
  • Received:2024-04-15 Revised:2024-06-28 Online:2024-10-31 Published:2024-12-16

摘要: 本研究计算了2019年1月—2023年12月川滇地区8071个中小地震的震源参数, 对2021年5月21日漾濞MS6.4地震、 2022年9月5日泸定MS6.8地震震源区及重点观测区域(龙门山断裂带、 红河断裂带南段与小江断裂带交会区域)进行了应力降的时间、 空间变化趋势分析。 根据应力降变化趋势, 本研究认为2021年漾濞MS6.4地震震源区观测到了显著的应力降前兆变化信息, 地震发生前1年起应力降即显著上升。 2022年泸定MS6.8地震在主震后短期内发生了应力降快速上升—下降的变化, 并且目前应力降没有明显的回升趋势。 川滇菱形块体南端红河断裂带与小江断裂带交会区域应力降值较高, 龙门山断裂带东北段应力降出现相对高值, 未来强震危险性值得关注。 因此, 应对这两个地区的应力降变化进行持续观测。

关键词: 川滇地区, 震源参数, 应力降, 2021年漾濞地震, 2022年泸定地震

Abstract: In this study, 8071 focal parameters of small and moderate earthquakes from January 2019 to December 2023 in the Sichuan-Yunnan region were calculated. The temporal and spatial variation trends of stress drop in the focal areas of the May 21, 2021 Yangbi MS6.4 earthquake, the September 5, 2022 Luding MS6.8 earthquake, and key observation areas (Longmenshan fault zone and the intersection area of the Honghe fault and Xiaojiang fault) were analyzed. According to the variation trends of stress drop, significant precursor changes were observed in the 2021 Yangbi MS6.4 focal area one year before the earthquake. The stress drop time series of the 2022 Luding MS6.8 earthquake shows a rapid rise and decline in the short term after the main earthquake; meanwhile, the stress drop has no obvious upward trends at present. The stress drops in the intersection area of the Honghe fault and Xiaojiang fault at the southern end of the Sichuan-Yunnan rhombohedral block and the northeast section of the Longmenshan fault zone are relatively high. Consequently, the future risk of strong earthquakes deserves attention, and the stress drop changes in these two areas should be continuously observed.

Key words: Sichuan-Yunnan region, Source parameter, Stress drop, The 2021 Yangbi earthquake, The 2022 Luding earthquake

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