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本文以野外地质调查资料为依据,利用地质的方法,讨论了昌马断裂东段的断层崖特征、断层位移量和沿昌马断裂带的古地震证据,确定了断层崖年龄和断层活动速率,粗略地估算了大震复发周期。研究结果表明自全新世以来北东东向断裂的活动性质由压性变为左旋张扭性;断层崖是断裂左旋张扭性活动的结果。断层的水平位移具有分级特点,断层崖具有两个明显的坡度中断,其形成年龄分别为12760年和1880年。公元104年前后,沿昌马断裂可能发生过一次7～7(1/2)级地震,大震复发周期为2620年(考虑蠕滑)和1500年(不考虑蠕滑),12760年和1880年以来的断层水平运动速率分别为4.5毫米/年和6.5毫米/年,水平位移与垂直位移之比值为4.7。
Based on the field geological survey data and the geological methods, the paper discusses the features of fault cliffs, the displacement of faults and paleoearthquakes along the Changma fault zone in the eastern section of Changma fault, and determines the age of the fault cliffs and the fault activity rate. Rough estimate of the recurrence cycle of the earthquake. The results show that since the Holocene, the activity of the NE-trending faults changes from compressive to dextral-torsional; the fault-cliffs are the result of the L-shaped torsional activity of faults. The horizontal displacement of the fault has grading features. The fault cliff has two obvious slope interruptions, and its formation ages are 12760 and 1880 respectively. Around the year 104 AD, an earthquake of magnitude 7-7 (1/2) probably occurred along the Changma fault. The recurrence period of the major earthquake was 2620 years (considering creep) and 1500 years (excluding creep), 12760 and 1880 years The horizontal movement rates of faults since 2004 are 4.5 mm / year and 6.5 mm / year, respectively. The ratio of horizontal displacement to vertical displacement is 4.7.