阿克陶M_S6.7地震前帕米尔东北缘地形变特征的GPS研究

ANALYSIS ON NORTHEAST PAMIR CRUSTAL DEFORMATION FEATURES BEFORE ARKETAO M_S6.7 EARTHQUAKE BASED ON GPS

利用2009～2015年4期GPS观测资料,获得阿克陶M_S6. 7地震前震中附近区域水平运动速率、主应变率、面膨胀率及最大剪应变率,结合区域构造背景分析该区域变形动态特征,结果表明:(1)本次地震震前研究区速度场由南向北逐渐减弱,研究区南部帕米尔区域整体运动速率高于北部的南天山区域,以发震构造为界南北部区域的速率大小和方向均有差异。(2)研究区现今应变率场与该区域长期的地质构造背景相一致,震前逐渐增强的压应变为本次地震提供发震背景。研究区剪应变变化趋势优于面膨胀变化趋势。

Based on an examination of four stages of global positioning system （ GPS ） observation date from 2009 to 2015, we obtained the horizontal movement velocity, principal strain rate, surface expansion rate, and maximum shear strain rate around the epicenter area before Arketao Ms 6.7 earthquake , combined with regional tectonic background analysis of the dynamic features of regional deformation, and resuhs showed that （ 1 ） the velocity field in the study area before the earthquake weakened gradually from south to north, the south of the study area Pamir region as a whole movement rate was higher than that in the north of south Tianshan area, and the size and direction of bound percentage rate had differences within the seismological structure. （2） The current strain rate field in the research area was consistent with the long-term geological tectonic background of the region, and the compress strain gradually increased before the earthquake provides a seismic back- ground for this earthquake. The change trend of shear strain in the study area was better than that of surface expansion.