【摘要】 断裂带近场变形特征不仅对新构造研究、地震预测等具有重要意义,对于直接服务于工程也具有很强的实用性。以鲜水河断裂八美—道孚段为研究区,选用多期L波段的雷达数据,采用永久散射体干涉测量技术(PS-In SAR,Persistent Scatterer Interferometric Synthetic Aperture Radar)进行了2007—2011年的变形测量,结合其他资料综合分析了断裂带近场复杂的变形规律:1断裂间震期变形以负值为主,速率南段大于北段,两侧LOS东向运动速率差有所区别,南西侧速率大于北东侧速率,远离断裂带速度差明显,靠近断裂带速度差小,反映了断裂的整体东向运动和左旋相对运动;2断裂带附近,PS(Persistent Scatterer)点变形以较小的负值和正值为主,反映了地表的抬升,所在位置主要为湿地、山脚地下水出露点、河岸沟壑,推测原因为气候变暖—冰川融化—地下水抬升使地表发生鼓胀变形,季节性冻胀导致的湿地趋势抬升增长,断裂带附近的破碎岩土体具有一定的膨胀性;3断裂带中古—八美段表现出大范围的升高变形为断裂在近场的逆冲抬升作用,以及宽大韧性剪切带的存在以此来吸收协调鲜水河断裂的整体变形;4在斜坡带上高变形PS"点团",反映了斜坡的重力变形作用,尤其在道孚—松林口段、乾宁盆地—龙灯坝段非常显著,体现了活动断裂带的地质灾害效应;5PS-In SAR高精度观测结果表明,活动断裂的变形是复杂的,在不同时期、不同分段、不同构造部位变形量和变形范围具有较大差异,不能简单考虑以断裂带为界的整体平移或升降。更多还原

【Abstract】 The near-field deformation is not only important for earthquake forecast and Neotectonics study but also important for the service to engineering geology. Adopting PS-In SAR(Persistent Scatterer Interferometric Synthetic Aperture Radar)technology and using L band data,the authors conducted the survey of near-field deformation around Bamei-Daofu section of Xianshuihe active fault from 2007 to 2011 and,based on analysis in combination with other materials,inferred some complex fault near-field deformation information: 1the deformation velocity of the north section is larger than that of the north section,and velocities on the two sides of the fault are somewhat different from each other,the velocity of SW wall is large than that of NE wall,the velocity difference of the far-field is more significant,and the velocity of the near-field is feeble; 2in area close to the active faulted zone,the values of PS(Persistent Scatterer)points deformation velocities are mainly comparatively small negative and positive values,reflecting the surface ascent and suggesting that the location is composed mainly of wet land,exposed point of ground water,bank and gully. It is inferred that these phenomena are attributed to surface bulging and deformation caused by weather warming—glaciers melting—uplift of ground water level,the tendency uplift of wet land resulting from seasonal frost heaving,and certain expansibility of cataclastic rock and soil near the faulted zone; 3the uplift deformation around Zhonggu-Bamei section results from the thrust movement near Xianshuihe fault,and the ductile shear zone absorbs and coordinates the entire block deformation; 4high deformation PS blocks reflect the slope gravity deformation,especially in sections of Daofu-shonglinkou and Qianning basin-Longdengba,revealing the geohazard effects of the fault; 5the precise PS-In SAR results show that the deformation of the fault is complex and shows remarkable differences in different sections,different periods and different tectonic locations,so we can’t simply consider the movement to be overall translation or elevation-subsidence with the faulted zone as the boundary.更多还原