高邮M_S 4.9地震震前异常时空演化特征分析

Analysis of Spatial-temporal Evolution Characteristics of Anomalies before the M_S 4.9 Gaoyou Earthquake

高邮-宝应M_S4.9地震是江苏陆地上22年来最显著的地震,震中位于江苏陆地中部地区,震前前兆异常丰富,异常的时空演化特征比较典型。震前2年显示震源区应力压性和周围张性特征,表现为水位、地电阻率和形变的群体准同步变化;震前1年集中出现小震条带活动的交汇现象;震前1月开始出现岩石裂隙变化的失稳现象,表现为周围水温、水化学的短期快速变化。高邮-宝应M_S4.9地震震前异常时空演化特征反映了周围岩石孕震过程中的变形和裂隙变化特征,对中强地震预测具有很好的借鉴意义。

The Gaoyou-Baoying M_S4.9 earthquake is the most significant earthquake on land in Jiangsu Province in the past 28 years.Its epicenter was located in the central part of Jiangsu Province.The earthquake precursors were abundant and its spatial and temporal evolution characteristics were typical.In the two years before the earthquake,stress-compression zone developed in the epicenter and tensile zone formed in the surrounding areas,showing up as quasi-synchronous changes of water level,ground resistivity and deformation.The convergence of small earthquake band activities occurred intensively in one year before the earthquake.The instability of rock fissure changes appeared in one month before the earthquake,which was characterized by short-term rapid changes of surrounding water temperature and hydrochemistry.The spatial and temporal evolution characteristics of anomalies before the Gaoyou-Baoying M_S4.9 earthquake reflect the deformation and fissure changes of surrounding rocks during seismogenic process,which has a good referential value in moderate and strong earthquake prediction.