2017年长岛M3.9地震序列性质的研究

Properties of Changdao M3.9 Earthquake Sequence in 2017

2017年3月3日长岛发生M3.9地震,震源深度10km。此后,震中出现密集小震活动,并持续至今,形成显著地震序列。该序列的发生使得长岛窗继2015年7月、2016年2月后再次出现开窗活动。此次地震序列空间分布主要集中在大竹岛—威海北断层,呈NWW—SEE方向分布,震源深度主要集中在9~13km。对长岛M3.9地震序列进行了地震活动性研究。通过对本次长岛窗频次、蠕变、地震参数特征及序列机理与发震构造的分析推测出长岛震群为前兆震群。

On March 3rd,2017,the M3.9 earthquake occurred in Changdao County with a focal depth of 10 km.Later,intensive small earthquakes occurred at the epicenter,and lasted till now to form a significant earthquake sequence.The occurrence of the sequence resulted in the re-windowing of Changdao earthquake window after July 2015 and February 2016.Regarding the spatial distribution,the earthquake sequence was mainly distributed in the Dazhu Isalnd-Weihai North fault in NWWSEE direction and with a focal depth of 9~13 km.Seismic activity was studied on Changdao M3.9 earthquake in the paper.According to the analysis on the frequency of Changdao seismic window,the creep deformation,earthquake parameter characteristics,the sequence mechanism and the seismogenic structure.It is speculated that Changdao earthquake swarm is a precursor earthquake swarm.