远场GPS同震位移的变形特征分析——以2011年日本东北大地震为例

摘要

After the 2011 Tohoku-Oki earthquake (Mw9.0),near-field GPS data and Ocean GPS data were separately derived for the fault slip model or joint inversion.However,up to now,far-field GPS data are rarely used for inverting the slip pattern.By calculating and comparing the dip and rake angle of four independent source solutions,the paper studies spatial distribution characteristics and rules of the far field earthquake horizontal deformation using GPS data from eastern Asia.Results show that for subduction earthquakes with low dip angles,the horizontal tensile displacement Green Function is the main part of the far-field horizontal displacement.We can also determine the range of effective GPS horizontal displacement data in the inversion.It provides the theoretical basis for joining far-field and near-field GPS observations to invert the fault slip models of the 2011 Tohoku-Oki earthquake (Mw 9.0) and to invert the dislocation Love numbers h and l.%利用2011日本东北大地震的亚洲东部GPS远场水平位移数据,通过计算及比较分析4个独立震源解和倾/滑角效应,研究了远场地震变形的空间分布特征和规律.结果表明,对于低角度逆冲型地震来说,水平位移格林函数在远场位移场中占主导作用.基于此确定了远场GPS水平位移场能在反演中有效利用的空间范围,为联合远场GPS数据和近场GPS数据反演断层滑动分布作理论准备,并为远场数据反演位错Love 数(h、l)提供理论依据.