青海昆仑山口西M_S8.1级地震地表破裂带特征与主要震害——对青藏高原区域稳定性评价的制约

Characteristics of the surface rupture zone and main seismic hazards caused by the M_S 8.1earthquake west of the Kunlun pass,China-Con straints on the regional stability of the Qinghai-Tibet Plateau

通过对昆仑山口西8.1级地震地表破裂全带的野外考察,发现本次地震地表破裂带由3条具有一定宽度和长度规模并且延伸稳定的右接斜列的破裂带组成,呈近东西(N80°W)走向延展,长度约350km;断裂错动以左旋走滑性质为主,发震断裂属昆仑山南缘断裂带;地震裂缝、地震鼓梁(包)、地震塌陷等形迹所构成的新破裂切割了老的地震形变带;宏观震中位于布喀达坂峰东侧25km附近,比较接近中国地震速报台网确定的仪器震中;极震区地震烈度为Ⅺ度。地震地表破裂带是本次地震形成的最主要的地震地质灾害。另外还伴随发育地震边坡崩塌、雪崩、湖岸震陷、山体震裂、地面喷沙冒水等地震地质灾害现象。

Field investigations of the whole M S 8.1earthquake surface rupture zone west of the Kunlun pass have revealed that this zone is composed of three persistent,right-lateral en-echelon rupture zones with a fairly great width and length.The extend in a nearly E-W direction(N80°W)for～350km.The displace-ments are mainly of sinstral strike-slip nature.The causative fault belongs to the south Kunlun marginal fault belt.The macroscopic epicenter is located～25km east of Buka Daba Mountain.The seismic intensity of the extreme seismic area is XI.The earthquake surface rupture zone is the most prominent seismic-ge-ological hazard caused by this earthquake.