Disaster Prevention Research Institute, Kyoto University, Uji, Japan.
National Research Institute for Earth Science and Disaster Resilience, Tsukuba, Japan.
Science. 2019 Aug 23;365(6455):808-813. doi: 10.1126/science.aax5618.
Investigating slow earthquake activity in subduction zones provides insight into the slip behavior of megathrusts, which can provide important clues about the rupture extent of future great earthquakes. Using the S-net ocean-bottom seismograph network along the Japan Trench, we mapped a detailed distribution of tectonic tremors, which coincided with very-low-frequency earthquakes and a slow slip event. Compiling these and other related observations, including repeating earthquakes and earthquake swarms, we found that the slow earthquake distribution is complementary to the Tohoku-Oki earthquake rupture. We used our observations to divide the megathrust in the Japan Trench into three along-strike segments characterized by different slip behaviors. We found that the rupture of the Tohoku-Oki earthquake, which nucleated in the central segment, was terminated by the two adjacent segments.
研究俯冲带中的慢地震活动可以深入了解巨震的滑动行为，这为未来大地震的破裂范围提供了重要线索。利用日本海沟沿线的 S-net 海底地震仪网络，我们绘制了构造地震的详细分布图，这些地震与极低频地震和慢滑事件相吻合。综合这些和其他相关观测结果，包括重复地震和地震群，我们发现慢地震的分布与东北-关东地震的破裂相补充。我们利用观测结果将日本海沟中的主震断层分为三个沿走向的段，它们具有不同的滑动行为特征。我们发现，发震于中间段的东北-关东地震的破裂被两个相邻的段所终止。
