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位于西秦岭西段的光盖山-迭山断裂带是由3条近平行的断裂所组成,其中坪定-化马断裂是该断裂带的主断层。坪定-化马断裂以宕昌岷江为界分为东、西两段,西段的新活动性明显强于东段。断裂西段线性特征明显,可见清晰的断层崖,不同期次的洪积扇上均有断层陡坎发育,晚第四纪以来有过明显的活动,最新一次活动的离逝时间约为1 kaB.P.左右。通过对断错地貌研究得到断裂晚第四纪以来的垂直滑动速率为0.49±0.08～1.15±0.28mm/a,左旋滑动速率为0.51±0.13mm/a。而断裂东段由多条斜交或近于平行的断裂所组成,活动性明显减弱,没有发现最新活动的证据。在地貌上多表现为线性沟谷,向东逐渐被褶皱所替代,从基岩断面及相关地貌特征来看断裂活动性质主要表现为逆冲兼具左旋走滑运动。
The Guanggaishan-Dieshan fault zone, located in the western part of West Qinling, is composed of three near-parallel faults, of which Pingding-Huamas fault is the main fault. The Pingding-Mama fault is divided into East and West sections by the Dangchang Minjiang River. The new activity of the western section is obviously stronger than that of the eastern section. The linear characteristics of the western segment of the fault are obvious. A clear fault cliff is visible with fault scarp development on all stages of the alluvial fan. Since the Late Quaternary, significant activities have been observed. The latest activity has a passing time of about 1 kaB About The vertical slip rate of the late Quaternary fault from the study of fault landform was 0.49 ± 0.08 ~ 1.15 ± 0.28mm / a and the left slip rate was 0.51 ± 0.13mm / a. However, the eastern segment of the fault consists of a number of oblique or near-parallel faults with significantly reduced mobility and no evidence of the latest activity. It is characterized by a linear valley in the landscape and a gradual eastwards fold replaced by folds. From the aspects of bedrock and related geomorphologic features, the fault activity mainly includes thrusting and left-lateral strike-slip movement.