岷山隆起边界断裂构造活动初步研究
The preliminary study of the tectonic activities along the boundary faults around the Minshan uplift, western Sichuan
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摘要: 岷山隆起西以岷江断裂为界,东为虎牙断裂。该地区构造活动强烈,地震活动频繁,是重要活动区。岷山隆起是岷江断裂和虎牙断裂由西向东的推覆逆掩运动差异运动导致的。GPS及地质研究表明岷江断裂、虎牙断裂现今仍在活动。岷江断裂为左右旋走滑断裂,运动速度大于2mm/a;虎牙断裂整体速度2.55mm/a,断裂性质为右旋走滑断裂,而震源机制解为左旋走滑断裂。这一结果,可能与GPS观测时段、位置及断裂面结构、几何特征有关。Abstract: As a segment of the eastern boundary of the Qinghai-Xizang Plateau, the Minshan uplift is characterized by severe tectonism and seismism, bounded by the Minjiang fault on the west and Huya fault on the east. The integration of GPS measurements and geological studies shows that the Minjiang and Huya faults are currently active. The former is a right-lateral strike-slip fault with a velocity of motion of more than 2 mm/a, while the latter also a right-lateral strike-slip fault with a velocity of motion of more than 2.55 mm/a. However the seismological observations are interpreted as a left-lateral strike-slip fault. The above-mentioned interpretations may be ascribed to the difference in time duration and position for GPS measurements, and architectures and geometry of fractured surfaces.