粤西沿海震动图的生成和研究

Generation and Study of Shaking Maps in the Coastal Western Guangdong

震动图是描绘地震产生的地面运动和可能破坏情况的有效工具,主要包括峰值地面速度(PGV)等值线图、峰值地面加速度(PGA)等值线图和仪器烈度分布图等。基于华南数字地震台网记录到的2010年7月9日MS3.7级阳江地震的数据资料,利用SAC和GMT软件从记录到的地震波形数据提取地面运动参数,生成了PGV和PGA等值线图,并用经验分级关系得到了仪器烈度分布图。结果显示,阳东地震台站(YGD)具有最大的PGV和PGA值,仪器烈度达到4度,等烈度区在陆区呈近南北向的半椭圆形分布。计算方法和研究结果对于在粤西沿海地区快速生成震动图和实现地震烈度速报具有重要作用和意义,同时为该地区抗震设防、地震危险性分析等研究提供基础资料。

Shaking maps are effective tools to describe ground motion and potential damage resulted from an earthquake, which include maps of Peak Ground Velocity （PGV） , Peak Ground Acceleration （PGA） and instrumental intensity. Based on the Ms3.7 earthquake occurred in Yangjiang area and recorded by the digital seismic network of South China on July 9, 2010, we used SAC and GMT to generate equivalent maps of PGV and PGA via ground motion parameters extracted from the recorded seismic waveform data. Then, this paper constructed the map of instrumental intensity from empirical table relations. The results show that Yangdong area has the biggest PGV and PGA, with an instrumental intensity degree of 4. The shape of the intensity contours on land looked like a half oval in near north-south direction. The calculation methods and research results of this paper have an important effect and a significant meaning on the shaking map generation and earthquake intensity rapid report in the western coast of Guangdong province. They also provide basic data for seismic fortification and seismic risk analysis in this area.