【摘要】 青藏高原东北地区是青藏块体、阿拉善块体和鄂尔多斯块体的汇聚部位 .为探索该区的构造特征 ,结合地质构造绘出 4条剖面线 .对剖面两侧各 40 km范围内的 ML≥ 3.0及研究区范围内 ML≥ 4.0的 388次地震做了重新定位 .重新定位后 ,36%的地震震中变化达 5km以上 ;给出深度的地震数比重新定位前增加了 50 % .青藏高原东北地区似三联点构造区 ,历史上曾发生过 3次 8级以上大震 ,现今微震活动也很频繁 ,反映出青藏高原东北地区三大块体间的现代构造运动仍然十分强烈更多还原

【Abstract】 The northeastern region of Qinghai Xizang plateau is the junction part of the Qing Zang block, Alxa block and Ordos block. To explore tectonic feature of this region 4 study profiles are selected by taking geological background into consideration. The M L≥3.0 earthquakes located within 40 km on both sides of the selected profiles and M L≥4.0 earthquakes in the studied region have been relocated. Of the 388 relocated earthquakes, 36% shift their previously determined epicenters by more than 5 km. The amount of relocation earthquake with focal depth determination increases 50% than that before relocation. In this quasi trijunction region of the northeastern of Qinghai Xizang plateau three M≥8 earthquakes occurred historically and microearthquakes are quite active at present, implying a strong tectonic activity persists here to the present.更多还原