云南省3次地震的余震活动的折合能量-地震矩关系

Scaling Law between Reduced Energy and Seismic Moment from Three Earthquake Sequences in Yunnan

折合能量或视应力如何随地震矩而变化,即折合能量-地震矩定标关系,是一个目前争议颇多的问题,需要更多的观测资料来参加讨论。本文利用2000年1月15日姚安5.9、6.5级地震,2001年10月27日永胜6.0级地震,2003年7月21日、10月16日大姚6.2、6.1级地震的余震序列的观测结果,讨论了这一问题。在估算能量时采用了Brune震源谱模型情况下的Andrews方法。结果表明,对这3次地震的余震序列来说,小于4级的地震活动的“折合能量”随地震矩而上升,而大于4级的地震数目虽不多,却呈现出折合能量不随地震矩而变化的特点。

The scaling law between reduced energy and seismic moment is a controversial issue in seismology. To resolve this question requires more observational data, especially local and regional ones. We collect observation reports of three earthquake sequences occurred in Yunnan Province and investigate the scaling law between reduced energy and seismic moment with these reports. We use Andrews method which is based on Brune＇s model to calculate radiated energy. Our result shows that reduced energy increases with seismic moment for earthquakes with ML 〈 4. For earthquakes with ML 〉 4, however,it seems that reduced energy doesn＇t vary with seismic moment.