新疆阜康断裂带甘河子段晚第四纪活动特征

为了解阜康断裂晚第四纪以来的活动特征, 准确评价该断裂的大震危险性, 在野外地震地质调查的基础上, 对变形的微地貌进行了测量, 开挖了2个大型古地震探槽, 并采集了系列释光年龄样品, 对阜康断裂甘河子段进行了细致研究.甘河子断裂段是一条全新世活动断裂, 全长约33 km, 构成博格达北麓与山前冲洪积扇的界线.该断裂晚第四纪期间活动性较强, 运动方式以向盆地方向的逆冲为主, 形成了一系列地质地貌现象.晚第四纪晚期以来, 断裂的平均垂直滑动速率在0.34~0.43 mm/a.全新世中期以来, 断裂有过2次古地震事件, 断裂大震(特征地震)的复发周期为2 100~3 750 a, 最新一次古地震事件造成的地表垂直位移量为1.5 m左右, 对应的古地震震级在7.2~7.4之间, 该次古地震事件离逝时间已达4.11 ka, 目前该断裂已经累积了较高能量. 

Late-Quaternary Activity Characteristics of the Ganhezi Segment of the Fukang Fault Belt, in Xinjiang

In order to understand the activity characteristics of the Fukang fault in Late-Quaternary, and accurately estimate the seismic hazard of the fault, a geological survey has been conducted along the Fukang fault. By surveying the deformation micro-topography, excavating two large paleoearthquake trenches, and dating a series of samples of thermoluminescence, the quantity activity characteristics of the Ganhezi fault segment of the Fukang fault belt are revealed. The Ganhezi fault segment is a Holocene active fault, with a total length about 33 km. The fault activity is obvious, generating a series of apparent geomorphic traces on the surface. Since the Late-Quaternary, the average vertical slip rate of fault is about 0.34-0.43 mm/a. Since the Mid-Holocene, there were two paleoearthquake events; the strong earthquake recurrence period of the fualt segment is about 2 100-3 750 a. The vertical surface displacement is about 1.5 m and the elapsed time is 4.11 ka of the latest paleoearthquake, corresponding to the paleoearthquake magnitude of between Ms7.2-7.4. The fault has accumulated a high energy so far.