鄂尔多斯北缘强震背景分析及未来地震趋势判断

Analysis on the activity background of strong earthquak and determination of its further trends on northern margin of the Ordos

基于鄂尔多斯块体的地质构造演变过程及历史强震活动规律,阐述南北地震带和龙门山断裂带强震时空分布规律对鄂尔多斯北缘的可能影响,对比分析鄂尔多斯其他3缘与北缘的地震活动。结果表明,青藏块体强震对鄂尔多斯北缘中强地震具有一定的触发作用;南北地震带中强以上地震的空间迁移特征表明,鄂尔多斯北缘将是未来中强以上地震的有利发震区域。2005年以来中小地震活动特征表明,鄂尔多斯北缘兼有M_S≥4.0地震平静和西北缘M_L≥3.0地震活跃两种异常特征。综合地震地质背景和近期地震活动研究结果分析认为,今后一段时间鄂尔多斯北缘有可能发生中强以上地震。

Based on the geological structure evolution and history of earthquake activity rules in Ordos block,the possible impact of the temporal distribution of earthquakes in north-south seismic belt and Longmenshan earthquake fault zone on the northern margin of the Ordos is described.The seismicity of the north margin of Ordos block with its other three margin areas is contrasted.The results show that,the strong earthquakes in Qinghai-tibet block can triger the strong earthquake in the northern ordos basin; space migration characteristics of medium-strong earthquakes in north-south earthquake zone show that north margin of Ordos will be the medium-strong earthquakes seismogenic area in future.Characteristics of medium and small earthquake activity since 2005 showed that there are two kinds of seismicity characteristics,Ms 4.0 earthquake calm and the ML acuity 3.0 earthquakes in the north margim of Ordos.Integrating seismic geologic background and recent seismic activity research,our analysis shows that medium-strong earthquakes will occur in norther margin of Ordos in recent future.