Seasonal Variations in Crustal Seismicity in San‐in District, Southwest Japan
Seasonal Variations in Crustal Seismicity in San‐in District, Southwest Japan
复制标题
日本西南部山阴地区地壳地震活动的季节变化
DOI：
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发表时间：
2019
影响因子：
5.2
通讯作者：
A. Kato
中科院分区：
文献类型：
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作者：
T. Ueda;A. Kato
越来越多的证据表明，地震活动在各种构造环境中受到季节性调制。识别地震活动的周期性变化提高了我们对地震触发物理学的理解。我们探索了季节性调制的地壳地震活动在山阴区，日本西南部，使用一种新的方法，采用来自基于概率的分布程序的不确定性。我们确定，从1980年到2017年，背景地震活动率的半年变化在春季和秋季增加，具有统计学意义。大的历史和现代地震的频率分布显示出与现代背景地震活动相似的模式，这表明山阴地区的地震活动在150多年来一直表现出季节性变化。这些观测结果可以解释为增加孔隙压力断裂带内，造成降水在秋季和减少表面质量，由于积雪融化在春季。
A growing body of evidence suggests that seismicity is seasonally modulated in a variety of tectonic environments. Identifying cyclic variations in seismicity improves our understanding of the physics of earthquake triggering. We explored seasonal modulation of crustal seismicity in San‐in district, southwest Japan, using a new method that adopts uncertainties derived from a probability‐based declustering procedure. We determined that semiannual variation in background seismicity rate, which increases in spring and autumn, is statistically significant from 1980 to 2017. The frequency distribution of large historic and modern earthquakes shows a similar pattern to recent background seismicity, suggesting that seismicity in San‐in district has shown seasonal variations for over 150 years. These observations can be explained by increasing pore pressure within fault zones, caused by precipitation in autumn and decreasing surface mass due to snow melting in spring.