부산대학교 도서관

The purpose of this study is to systematically investigate the activity characteristics of the significant earthquake swarms in the Bohai Rim region. We use the epidemic-type aftershock sequence (ETAS) model with good fitting and the Ogata–Katsura 1993 model with full consideration of small earthquake information to fit the sequence parameters of the significant earthquake swarms since 2012, including Changdao, Rushan, Gaizhou, and Yinghaixiu, and analyze their parameter variation characteristics. The results show that the significant earthquake swarms have some differences in time but not in space, and only some migration phenomena exist in their development processes. The b value is significantly affected by the activity of earthquake swarms, with many fluctuations. Before the occurrence of significant earthquake swarms or strong earthquakes, there are different degrees of low b phenomenon, reflecting the stress accumulation before significant earthquakes (earthquake swarms), and the activity of earthquake swarms leads to the adjustment of crustal stress. The ETAS model shows a good fitting effect on the sequence of the Bohai Rim earthquake swarms. The α value of the earthquake swarms is low, and the cascade triggering ability is high, which also produces more earthquake events for the determination of the α value as an earthquake swarm. There are some differences in the activity of small earthquake swarms among the significant earthquake swarms; for example, the triggering ability of the Changdao earthquake swarm is stronger, the attenuation of the Rushan earthquake swarm is slow, the stress level of the YinghaiXiu area is lower, and the stress level of the Gaizhou area is higher. This study is of great significance to the investigation of the activity characteristics of earthquake swarm sequences and the occurrence of future earthquake swarms or significant events.