2022年青海门源M_(S)6.9地震前地壳形变特征初探  

Characteristics of Crustal Deformation beforethe 2022 Menyuan M_(S)6.9 Earthquake in Qinghai Province

作　　者：蔡小超 唐红涛[2] CAI Xiaochao;TANG Hongtao(Department of Civil Engineering,Henan Vocational College of Water Conservancy and Environment,Zhengzhou 450008,China;The Second Monitoring and Application Center,Xi’an 710054,China)

机构地区：[1]河南水利与环境职业学院土木工程系,郑州市450008 [2]中国地震局第二监测中心,西安市710054

出　　处：《大地测量与地球动力学》2023年第7期669-673,共5页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(52008228)。

摘　　要：基于2013~2021年4个GPS周期运动场数据,计算获得各周期应变场结果,探讨2022年青海门源M_(S)6.9地震前4个周期的应变场时空演化特征。结果表明:1)主应变能够更好地反映单点主压-主拉的应变特征;2)应关注最大剪应变率场高值集中区,2016年、2022年门源地震前第一、四周期高值区空间位置的分布对地震风险区的研判具有一定指示作用;3)正-负转换高密度梯度带与等值线四象限中心是面膨胀率场需要关注的重点区域,可作为中强地震的形变前兆信息。Based on the motion field data of four GPS periods from 2013 to 2021,we calculate the strain field of each period,and discuss the spatiotemporal evolution characteristics of strain field in the four periods before the 2022 Menyuan M_(S)6.9 earthquake in Qinghai province.The results show that:1)The principal strain can reflect the strain characteristics of main pressure and main tension of single point.2)The maximum shear strain rate field should pay more attention to the high value concentration area.The spatial distribution of the high value area in the first and fourth cycles before the Menyuan earthquake in 2016 and 2022 has implications for the study and judgment of earthquake risk area.3)The positive-negative conversion high-density gradient zone and the center of four quadrants of strain field isoline are the key areas of the surface expansion rate field,which can be used as the deformation precursor information of medium and strong earthquakes.

关 键 词：门源地震 应变场特征 GPS形变数据 震源机制 构造活动 

分 类 号：P315[天文地球—地震学]