2023年8月6日山东平原M5.5地震破裂过程快速反演

北京时间2023年8月6日2时33分,山东德州市平原县发生M5.5地震。震后第一时间利用国家烈度速报与预警工程项目在山东地区建成的强震台站数据对该次地震进行破裂过程快速反演。基于破裂方向性效应,通过趋势面拟合的方法确定了此次地震的主破裂面。反演得到的破裂模型表明,破裂面呈现NE-SW走向,破裂主要由震中向NE方向拓展,地震破裂持续时间为8s,破裂长度约为8km,最大滑动量为0.024m。相对于6级以上地震,此次地震震级相对较小,破裂最大滑动量偏小,破裂过程也相对简单。震后统计的余震分布与破裂模型显示的破裂区域能够较好地吻合,在破裂区域的边界附近余震分布也较为集中,推断可能是由于积累的应力能量进一步释放引发的余震。

Rapid Inversion of the Rupture Process of the M5.5 Earthquake in Shandong Pingyuan on August 6, 2023

At 2:33a.m. on August 6,2023(Beijing time),an M5.5 earthquake occurred in Pingyuan county,Dezhou city,Shandong Province. Shortly after the earthquake,the rupture process of the earthquake was quickly inverted using the data of the strong motion stations in the Shandong region built by the National Intensity Rapid Reporting and Early Warning Engineering Project. Based on the directional effect of the rupture,the main fault plane of this earthquake was determined through trend surface fitting. The inversion rupture model shows that the rupture plane is in NE-SW trend,and the rupture mainly extends from the epicenter to the northeast. The rupture duration is 8 seconds,the length of the rupture is about 8 kilometers,and the maximum sliding amount is 0.024 meters. The magnitude of this earthquake is relatively small,so the maximum sliding amount of the rupture is relatively small,and the rupture process is also simple. The distribution of aftershocks is in good agreement with the rupture area shown by the rupture model. The aftershock distribution near the boundary of the rupture area is also relatively concentrated,suggesting that the earthquake may be caused by the further release of accumulated stress energy.