2012年河源M4.8级地震活动特征及预测研究

对2012年2月16日河源MS4.8级地震序列进行研究,提出河源MS4.8级地震属于1962年河源MS6.1级主震后的晚期强余震,通过震源机制解结果分析,主压应力方向和华南地区主压应力方向基本一致,为走滑兼正断错动。水库西北角附近可能存在尚未明确的北西向小破裂带,b值计算表明河源库区1960年至今始终处于低应力状态,地震前40 d开始,河源微震频度（ML〉0.1）和距震中30 km的深孔地电阻率同步发生明显高值异常。预测河源地区未来发生强破坏性地震的可能性比较低。

Research on Seismicity Features and Prediction of 2012 Heyuan M4.8 Earthquake

The research on M4.8 earthquake sequence of Feb.16,2012 shows that the earthquake was late strong aftershock of Heyuan MS6.1 principal earthquake in 1962.The focal mechanism solution identifies that the principal compressive stress of the earthquake has almost the same direction as that in South China,and is defined as strike-slip and fault rupture.The possible unconfirmed small broken belt in northwest of reservoir is also identified as the possible seismogenic structure for this earthquake.The b value calculation shows that Heyuan Reservoir areas were in the low stress state since 1960,so it is believed that strong destructive earthquake is unlikely to occur again in the future.It is noted that,40 days before this M4.8 earthquake hit Heyuan,the microseismic frequency of Heyuan(ML≥ 0.1) and deep borehole earth resistivity 30 km away from the epicenter simultaneously showed apparently abnormal high value.So far this is the only time that short-term information of seismometry and premonition with prediction significance was simultaneously acquired before happening of moderate strong earthquake in south China.