汶川M_S 8.0地震后龙门山裂断带地应力状态研究  

Reaseach on the stress state along the Longmenshan fault belt after the Wenchuan M_S 8.0 earthquake

作　　者：吴满路[1,2] 张岳桥[1,2] 廖椿庭[1,2] 陈群策[1,2] 马寅生[1,2] 丰成君[1,2] 张重远[1,2] 严君凤[3] 吴金生[3] 

机构地区：[1]国土资源部新构造运动与地质灾害重点实验室,北京100081 [2]中国地质科学院地质力学研究所,北京100081 [3]中国地质科学院探矿工艺研究所,成都611734

出　　处：《地球物理学进展》2013年第3期1122-1130,共9页Progress in Geophysics

基　　金：国土资源部深部探测技术与实验研究专项(SinoProbe-06);科技部973项目(龙门山地质构造断裂带及其与汶川孕震动力条件分析(2008CB 425702)共同资助

摘　　要：汶川MS8.0地震发生后,为确定龙门山断裂带及邻区现今地应力状态,应用水压致裂法开展了地应力原地测量,获得了6个测点应力大小和方向.结果显示,位于震中区映秀测点,在170～180m深度,水平最大主应力值为16MPa左右,最大主应力方向为NW;龙门山断裂带西南段上下盘硗碛电厂测点、宝兴测点,在200～350m深度范围内,获得的最大水平主应力达25MPa,最大主应力方向为NW-NWW;靠近鲜水河断裂带的康定测点,在170～180m深度,水平最大主应力值仅为6MPa左右,最大主应力方向性不明显;文县测点,在195m深度,水平最大主应力值为13MPa左右,最大主应力方向为NE-NEE;松潘测点由于岩石较破碎,在170m深度测得的水平最大主应力值仅为3MPa左右,不能代表该区的应力状态.测量结果表明应力量值具有随深度增加而增大的趋势,与震前龙门山断裂带及邻区应力测量结果比较,震后龙门山断裂带西南段仍属于高应力区,震中区及北东段外围属于中等应力区.此外利用库仑摩擦滑动准则对龙门山断裂带活动性进行了分析,这将为评价龙门山断裂带余震和今后强震发展趋势提供科学依据.After the Wenchuan Ms 8. 0 earthquake in west Sichuan （China）, in situ stress measurements werecarried out along the Longmengshan fault belt, with the purpose to obtain stress parameters for earthquake hazards assessments. Six boreholes were drilled and in situ stresses were measured by using hydraulic fracturing for deeper depth. The results show that the maximum horizontal stress obtained at 170 - 180 m depth is about 16 MPa, oriented in NW, in the epicenter area at Yingxiu Township, and at 200-350 m depth is about 25 MPa, oriented in NW NWW, at Baoxing County and site Yaoji in SW Longmenshan, and at 170- 180 m depth is about 6 MPa,Directional not obvious, near Kangding, at the southernmost zone of Longmenshan, and at 195 m depth is about 13 MPa, oriented in NE-NEE, at site Wenxian and at 170 m depth is about 3 MPa, Directional not obvious, at site Songpan. Because rock is broken, measured stress value of the lower, it does not represent the stress state in the zone. Hydraulic fracturing was conducted at borehole depth from 100 to 400 m and the results show tendency of increasing in stress with depth. Compared with the results measured before the Wenchuan earthquake along the Longmenshan belt and in the Tibetan Plateau, it is concluded that stress level is relatively high in the southwest segment of Longmenshan, and is still moderate in the epicenter zone. Northern Wenxian area also was in medium stress level. With when using Coulomb friction sliding rule for the longmenshan fault zone activity was analyzed, and this will be for evaluation the longmenshan fault zone development trend in the future earthquake aftershock and provide the scientific basis.

关 键 词：汶川MS8 0地震 龙门山断裂带 水压致裂测量 

分 类 号：P315[天文地球—地震学]