六安-霍山地震危险区地震活动和地震构造

SEISMIC ACTIVITIES AND STRUCTURES OF THE LIU'AN-HUOSHAN SEISMIC RISK AREA

运用深、浅部构造对比方法与宏、微观构造解析技术 ,结合历史地震资料分析结果 ,探讨了中强震过渡区地震构造环境的研究途径。圈定出六安 -霍山地震危险区。对该地震危险区进行立体综合剖析 ,推演出未来中强震发生的空间部位 ,并预测了研究区未来可能发生地震的震源深度、震级。

In this paper, the approach to the understanding of seismic tectonic environment in moderate and strong earthquake areas are discussed through the antithetic analysis of shallow and deep structures, macro microstructural analysis, and analysis of both historical and recent seismic data. Taking the Liu'an Huoshan seismic risk area as an example, the authors have carried out a three dimensional analysis of the area, and predicted the potential location of future earthquake and its corresponding parameters including focal depth, magnitude, and the attenuation direction of the isoseism. The results of this study indicate that the NE , NW and nearly E W trending faults in this area exhibit obvious activities. The junctures of these 3 sets of faults are prone to stress concentration, making up the seismogenic background for future moderate strong earthquake in this area. The most possible location for future earthquakes is the western side of the Funanshan Mountain, the juncture between the Luo erling Tudiling, Meishan Longhekou and Xiafuqiao Hujiahe Faults. The seismogenic model for this area is constructed on the basis of analysis of seimotectonic environment by referring to the interpretation of remote sensing images, the results of seimogeolo^gic investigation and the Suizhou to Halqin Qi geoscience transect that obliquely passing through this area. Based on the focal depth, the features of isoseimal lines and the migration regularity of the past seismic events occurred in this area, the focal depth of the future earthquake is postulated to be 12～15km, and the isoseism will be equidimensional in shape. It is proposed that the Liu'an Huoshan seismic risk area is obviously active. As the area is broken, however, energy is difficult to be accumulated and large earthquake is difficult to be generated. It is suggested, therefore, that the future earthquake will be a moderate strong earthquake.m ,andtheisoseismw