基于亚失稳的2021年5月漾濞Ms6.4地震的视波速比场的推演  

Deduction of meta-instability of the Yangbi Ms6.4 earthquake in May 2021

作　　者：李守勇 宋秀青[2] Li Shou-Yong;Song Xiu-Qing(Handan Central Seismic Station,Handan Hebei 056001,China;Shanghai Earthquake Agency,Shanghai 200062,China)

机构地区：[1]邯郸地震监测中心站,邯郸056001 [2]上海市地震局,上海200062

出　　处：《Applied Geophysics》2024年第2期402-408,422,共8页应用地球物理（英文版）

摘　　要：亚失稳实验为前兆信息的提取和地震预测的研究提供了理论依据。为了研究地震前兆信息,根据地震波速度与应力的关系实验结果,计算了2021年5月1日至21日漾濞Ms6.4地震前,经度E98°-E102°,纬度N24°-N28°地震的视波速比,对其插值实现区域网格化,分析了视波速比场的梯度和梯度的散度,发现在点(N26.10°,E99.59°)和点(N25.73°,E99.87°)为中心释放能量,它们连线的走向为145°,在以点(N25.81°,E99.59°)和点(N26.58°,E100.26°)的连线为轴线的多点吸收能量,其走向为38°。认为具有亚失稳态的特征、是前兆信息,由亚失稳理论推演出0至5日内,在点(N26.10°,E99.59°)或点(N25.73°,E99.87°)或其连线的附近将发生地震,断层的破裂长度约为49.8km,换算为Ms6.8,与测量的在点(N25.67°,E99.87°)发生的Ms6.4地震对比是理想的,认为该方法可以为此类浅源走滑型地震且有一定数目前震的前兆研究提供参考。The meta-instability experiment provides a theoretical basis for the extraction of precursor information and the study of earthquake prediction.To study the precursor information of earthquakes,the apparent wave velocity ratio of earthquakes with a longitude of E98°–E102°and latitude of N24°–N28°before the Yangbi Ms6.4 earthquake on May 1 to 21,2021,was calculated based on experiment results of the relationship between seismic wave velocity and stress.Regional gridding was achieved by interpolation,and the gradient of the apparent wave velocity ratio fi eld and its divergence were analyzed.Energy was found to have been released at points(N26.10°,E99.59°)and(N25.73°,E99.87°)as the center,with a connecting line strike of 145°.Energy was absorbed at multiple points along the axis of the line connecting points(N25.81°,E99.59°)and(N26.58°,E100.26°),with a strike of 38°.Precursor information is a characteristic of meta-instability.According to the meta-instable theory,an earthquake will occur near points(N26.10°,E99.59°)or(N25.73°,E99.87°)or on the line connecting them within 0 to 5 days.The rupture length of the fault was about 49.8 km,which,when converted to Ms6.8,is ideal for comparison with the measured Ms6.4 earthquake that had occurred at point(N25.67°,E99.87°).It is believed that this method can provide a reference for the study of precursors of shallow strike-slip earthquakes with a certain number of foreshocks.

关 键 词：视波速比场 亚失稳 应力场 梯度的散度 

分 类 号：P315.72[天文地球—地震学]