The Preliminary Analysis of the Characteristics of Geomagnetic Harmonic Wave Amplitude Ratios before the Gaoyou-Baoying MS4.9 Earthquake

In this paper,the Gaoyou-Baoying M_S4.9 earthquake was analyzed by the geomagnetic harmonic wave amplitude ratios method. The earthquake was an isolated seismic event,before and after which there were no other earthquakes occurred in this region. The dense distribution of geomagnetic observataries provided an advantage condition for the analysis of characteristics of the geomagnetic harmonic amplitude ratios. The analysis results verify the former knowledge of anomaly characteristics of the geomagnetic harmonic amplitude ratio,that is,the anomalous characteristics of the earthquake mostly appeared during the decline-turning-recovery rising process. The results also show that the change of the anomalies was asynchronous at the observatories close to the epicenter, namely, the anomalous characteristics were different between the H and the D components,as well as between the long and short periods.

2012年7月20日江苏宝应M4.9地震加速度场的计算

运用ShakeMap中的计算方法,计算2012年7月20日江苏宝应M 4.9地震的加速度场,结果发现,水平向峰值加速度的分布与真实的烈度分布基本一致,说明利用江苏省强震动台网43个固定台站的观测资料,可为快速评定此次地震的烈度提供科学、准确的参考信息。

高邮4.9级地震前滁州地震台电磁扰动异常分析

采用超限率方法,分析滁州地震台2011—2013年电磁扰动数据,结果发现,2012年7月20日江苏高邮M 4.9地震前,电磁扰动脉冲超限频次和超限幅度均出现明显增强;进一步分析该台电磁扰动子夜时段(00:00—04:00)的脉冲变化,结果显示,子夜时段的电磁扰动脉冲在震前明显增强。分析认为,2012年滁州地震台电磁扰动脉冲增强变化与高邮M 4.9地震具有明显的相关性。

利用重复地震研究广东阳江地区地壳介质变化

利用射线追踪方法对广东阳江地区的重复地震进行位置归一处理,提高走时精度以达到观测地壳介质变化的目的。文中计算了阳江地区2002年1月至2007年9月ML≥2.0重复地震序列经射线追踪法校正后的P波走时差。结果显示,在2004年阳江4.9级地震前信宜台、湛江台、肇庆台的记录观察到该地区短期的地壳介质速度明显升高的现象。