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地震 ›› 2022, Vol. 42 ›› Issue (4): 60-69.doi: 10.12196/j.issn.1000-3274.2022.04.005

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2021年云南漾濞6.4级地震的前震序列频谱特征

孙玺皓, 苏维刚, 张朋涛, 刘磊, 张丽峰   

  1. 青海省地震局, 青海 西宁 810003
  • 收稿日期:2021-10-25 修回日期:2022-04-28 发布日期:2023-03-31
  • 作者简介:孙玺皓(1986-), 男, 黑龙江庆安人, 工程师, 主要从事地震预测预报研究。
  • 基金资助:
    青海省重大科技专项(2019-ZJ-A10); 中国地震局监测预报司震情跟踪青年课题(2021010119)

Spectral Characteristics of Foreshock Sequence of the 2021 Yangbi MS6.4 Earthquake in Yunnan, China

SUN Xi-hao, SU Wei-gang, ZHANG Peng-tao, LIU Lei, ZHANG Li-feng   

  1. Qinghai Earthquake Agency, Xining 810003, China
  • Received:2021-10-25 Revised:2022-04-28 Published:2023-03-31

摘要: 2021年5月21日21时48分云南漾濞发生6.4级地震, 基于此次地震序列的波形资料, 利用频谱偏移法(快速傅里叶变换)计算主震前3.0~4.9级地震频谱, 发现3.0~3.9级地震序列频谱的频带较宽, 优势频段为0~5 Hz; 4.0~4.9级地震序列频谱的频带变窄, 且较为显著地向低频端偏移, 优势频段为0~1.5 Hz。 分析认为, 4.0~4.9级地震频谱偏移异常能够反映震源区应力加载过程, 在未来震情跟踪过程中要重点关注4.0~4.9级地震频谱偏移异常出现后周边区域强震发生的可能性。

关键词: 2021年漾濞6.4级地震, 频谱偏移, 快速傅里叶变换, 优势频段

Abstract: The Yangbi MS6.4 earthquake occurred in Yunnan Province at 21∶48 on May 21, 2021. Based on the waveform data of the earthquake sequence, the frequency spectrum of M3.0~4.9 earthquakes before the earthquake is calculated by FFT (Fast Fourier Transform Algorithm) method. It is found that the frequency band of M3.0~3.9 earthquake is relatively wide, and the dominant frequency band is 0~5 Hz. The frequency band of M4.0~4.9 earthquake sequence is narrow and shifted to the low frequency end. Its dominant frequency band is 0~1.5 Hz. The analysis shows that the abnormal frequency shift of M4.0~4.9 earthquakes can reflect the stress loading process in the focal region. In the process of future earthquake tracking, we should pay more attention to the possibility of strong earthquakes occurring in the surrounding area after the abnormal frequency shift of M4.0~4.9 earthquakes.

Key words: the 2021 Yangbi MS6.4 earthquake, Spectrum shift, FFT, Dominant frequency band

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