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昌马1932年12月25日7.5级地震主要是昌马—俄博断裂带西段现今强烈活动的结果。该带的垂直差异运动西段此东段更为明显。第四纪以来,该带的活动通常是以北北西、北西西向两组扭裂面方式表现出来的。地震形变带就沿其展布,北北西向形变带显示顺时针扭动,北西西向形变带为反时针扭动,与发震断裂的两组扭裂面不仅方向吻合,而且扭动方向一致。平面上形成一系列的反“S”状构造,从而认为这种单体非反“S”状,而总体排列为反“S”状的构造是祁只系西翼挽近和现今活动的地质标志之一。根据地震形变带的分析,地震时震区的平均主压应力方向为北30～40°东,与土体应力解除所得平均主压应力方向北33°东相一致。运用地质类比法,认为民乐地区有同昌马地震相似的构造条件和岩性条件,所以有发生中强地震的可能。
Changma December 25, 1932 The 7.5-magnitude earthquake was the result of today’s intense activity in the Changma-Bujube fault western section. The eastern section of the westward movement of the belt is more obvious. Since the Quaternary period, the activities of the belt are usually manifested by two sets of twisting planes in North, West and North West. The seismic deformation belt spread along the belt. The north-northwest deformation belt shows a clockwise twist, and the northwest-west deformation belt turns counterclockwise. The two torsional fracture surfaces coincide with the directions of the twisting faults. The formation of a series of anti-“S” structure in the plane, so that this monomer non-anti “S” shape, and the overall arrangement for the anti-“S” -like structure is Qi only the western wing of the recent and now active geology One of the signs. According to the analysis of the seismic deformation zone, the direction of the average principal compressive stress in the earthquake area during the earthquake ranged from 30 ° east to 40 ° east, consistent with the east 33 ° north of the direction of average principal compressive stress obtained from stress relief. Using geologic analogy, it is considered that there are similar tectonic and lithologic conditions in Minle area with the Changma earthquake, so it is possible to have moderate-strong earthquakes.