芦山地震发震构造特征研究

The earthquake has a characteristic of sudden and destructive, so it is the largest natural disaster which can not be accurately forecasted until now. Two earthquakes has happened in Longmen Mountain and its eastern foreland basin which are both located in the eastern margin of the Qinghai-Tibet Plateau in the past five years.These two earthquakes triggered serious secondary geological disasters, heavy casualties, and made economic construction face difficulties. After the Wenchuan earthquake, the Chinese and foreign experts has made extensive research on the rupture characteristics of Earth's surface, secondary geological disasters, tectonic stress field at present,Earthquake dynamics mechanism of the Longmen mountain fault zone and so on, and has made lots of achievements. But he Lushan 7.0 earthquake happened in the Sichuan basin.Experts and scholars have different views on the earthquake, and have made less research on the tectonic units that occurred these two earthquakes, the characteristic of faults that caused earthquakes and the trend of earthquakes followed by .So under the guidance of the theory of modern structural geology, this project will combine the remote sensing, geology and seismic,and utilize the technologys of fault-related folds and balanced cross-section, work out the geological profile through the basin - the epicenter – Longmen mountain and simultaneously interpret the deep and shallow structure, to reveals the tectonic environment, the structural characteristics and the response structural characteristics of the epicenter,to study the structural mechanism that were resulted in the earthquakes , to explore the trend and the direction of earthquakes followed by, to provide the basis for post-disaster reconstruction and construction of large-scale projects in Sichuan.

地震具有突发性和破坏性，是迄今为止尚不能准确预报的最大的自然灾害之一。青藏高原东缘的龙门山及其前陆盆地近五年来发生两次强震，导致严重的次生地质灾害，造成大量人员伤亡，给经济建设带来重重困难。汶川地震后，中外专家对龙门山构造带的地表破裂、次生灾害、现今应力场、地震动力学机制等进行了广泛研究，取得了丰硕成果。但芦山7.0级地震发生在四川盆地，专家学者对此次地震的性质众说纷纭，对于两次地震的发震构造单元、发震断裂特征以及今后发震演变趋势研究偏少。本项目欲在现代构造地质学理论的指导下，将遥感、地质、地震相结合，运用断层相关褶皱与平衡剖面技术，通过对穿过盆地-震中-龙门山的地质大剖面的编制与深浅构造的统一解释，揭示发震构造背景、发震构造特征及震中构造对地震的响应特征，研究强烈地震发震构造机理，探讨今后地震可能发震趋势与方向，为灾后重建及四川大型工程建设有效避开潜在地震危险区提供依据。

发生于2013 年4 月20 日8 时02 分的四川省雅安市芦山县（北纬30.3°,东经103.0°）7.0 级地震是继“5.12”汶川地震之后相隔五年的又一次强震。本次研究在收集了遥感、DEM、地面地质及芦山震区人工地震剖面基础上，对网上公布的芦山地震震中数据、地震机制解、余震分布数据和地震的地表破裂情况进行了分析，初步推断认为引发芦山地震的断裂是盆地内西南侧地腹隐伏断裂或新生断裂。并将芦山地震与汶川地震进行了综合对比，认为两次地震均属构造地震，从构造动力学角度分析均与印度板块向北挤压碰撞有关，但两次地震发震断裂和发震构造单元特征是不同的，应属两次独立地震。