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阿尔金断裂带是青藏高原北边界的1条近EW向延伸长约1600km的大型左旋走滑断裂带,也是晚第四纪活动性最强的断裂带之一,被分为11个破裂段。利用高精度卫星影像结合野外地质地貌调查,通过Trimble VX扫描测量了阿尔金断裂带阿克塞段半果巴观察点的断错微地貌,显示冲沟左岸T1阶地保存了最新1次地震的位错约6~7m。选择冲沟右岸跨断塞塘开挖探槽,采集了14C样品进行年代测定,对该探槽的古地震事件进行了分析。探槽揭示了12套地层单元,记录了4次古地震事件,结合之前的研究,利用逐次限定方法可以把阿克塞段的最新2次古地震事件的发生时间分别限定在1 180a BP左右和507~230a BP。
The Altun fault zone is a large left-lateral strike-slip fault zone near the northern Ebb of the Qinghai-Tibet Plateau with an extension of about 1600 km. It is also one of the most active fault zones in the late Quaternary and is divided into 11 fractures. Using the high-precision satellite imagery combined with field geomorphology investigation, the fault micro-topography of the half-pachyammetry observation point in the Axis fault section of the Altyn Tagh fault was measured by Trimble VX scanning. The latest earthquakes were preserved in the T1 terrace on the left bank of the gully Wrong about 6 ~ 7m. The right bank of the gully was cut across the Xiantang Excavation Channel. Samples of 14C were collected for dating and the Paleoclimate events of the channel were analyzed. The trenches revealed 12 sets of units and recorded 4 paleoearthquakes. Combined with previous studies, the occurrence of the latest 2 paleoseismic events in the Axe section can be limited to 1 180 BPM 507 ~ 230a BP.