2021年青海玛多M_(W)7.3地震同震和早期震后断层滑动模型及发震构造摩擦属性  

Coseismic and early postseismic fault slip model and the seismogenic fault friction properties of the 2021 Qinghai Madoi M_(W)7.3 earthquake

作　　者：赵磊 许文斌[1] 方楠 刘计洪 冯光财[1] ZHAO Lei;XU WenBin;FANG Nan;LIU JiHong;FENG GuangCai(School of Geosciences and Info-Physics,Central South University,Changsha 410000,China)

机构地区：[1]中南大学地球科学与信息物理学院,长沙410000

出　　处：《地球物理学报》2023年第3期1086-1097,共12页Chinese Journal of Geophysics

基　　金：国家重点研发项目(2019YFC1509205);国家自然科学基金项目(42174023)共同资助。

摘　　要：地震同震和早期震后断层滑动是研究发震断层深浅部孕震形态及摩擦性质的重要手段.本文基于雷达干涉测量(InSAR)数据获得了玛多地震同震和早期震后形变场,并反演得到了发震断层的滑动分布模型.研究结果表明同震滑动主要分布在上地壳浅部,并且存在多个滑动亏损区域.发震断层在东端分叉处的倾向与主断裂和西端倾向相反.基于N-SBAS方法获得的震后4.5个月形变场显示,断层近场震中区域的累积形变量达5 cm,远场区域累积形变达2 cm.震后早期余滑分布在断层浅部和深部以及两侧的横向延展区域;部分余滑区域与同震区域重叠.其中,上地壳浅部的余滑达20 cm且填充了同震滑动亏损.时序地震矩显示上地壳浅部区域在震后快速余滑而深部稳定滑动,表明了发震断层区域的复杂摩擦属性.Coseismic slip and early post-earthquake afterslip are important ways to observe seismogenic morphology and friction properties of seismogenic faults. We use InSAR data to obtain the coseismic and early postseismic deformation and estimate the fault slip distribution model. The coseismic slip is mainly distributed in the shallow upper crust and shows several shallow slip deficits. The dip in the eastern branches fault is opposite to the western and main segment. We process 4.5 months postseismic deformation based on the N-SBAS method, which accumulates ~5 cm displacement in near-field and ~2 cm in far-field. The afterslip distributed in both updip and downdip areas and laterally extended alongside western and eastern ends. The shallow upper crust afterslip fills the shallow slip deficit, and several areas overlap the coseismic slip. The maximum afterslip is ~20 cm in the updip region. The temporal-spatial moment shows rapid afterslip in the shallow upper crust and stable afterslip in the downdip area, which indicates the complex friction properties of the seismogenic fault.

关 键 词：断层模型 余滑分布 震后形变 摩擦属性 

分 类 号：P315[天文地球—地震学] P228[天文地球—固体地球物理学]