【摘要】 利用云南区域数字台网波形资料,采用多台法计算了2008年8月30日在川滇交界攀枝花发生的6.1级地震前后波速比VP/VS变化,结果表明:地震前3年,波速比出现一次持续时间相对较长的下降过程;震前0.5年,又出现一次持续时间相对较短、急剧下降的过程,且伴随有多次低值异常;震前2个多月至发震,波速比从低值回升至均值附近;震后波速比维持在均值上下波动,并伴有高值出现。震区南部的元谋地区和东北部的巧家—普格一带波速比异常较为明显。更多还原

【Abstract】 Basing on waveform data in Yunnan Regional Digital Network,we calculated the variation of wave velocity ratio before and after the PanzhihuaMS6.1 earthquake which occurred on Aug.30,2008 in the boundary between Sichuan and Yunnan by multi-station method. The results showed that the wave velocity ratio decreased for a relatively long duration in study area in three years before the earthquake,and it decreased sharply for relatively short duration,accompanied by a number of low abnormal in half a year before the earthquake. From more than two months before the earthquake to earthquake occurrence,wave velocity ratio gone up again from the low value to the mean value,after the earthquake,it maintained around the mean value accompanied by the high value. Wave velocity ratio anomalies were obvious near Yuanmou and Qiaojia-Puge respectively in southern and northeast of earthquake zone.更多还原