芦山地震科考人工爆破与构造地震特征对比分析

Comparison between the artificial blasting and tectonic earthquakes in Lushan County

对四川芦山地震科考人工爆破与构造地震特征进行了对比分析,用实例说明了不同震中距、不同地区、震级相近的两类地震事件震相特征的不同,指出在震中距小于120 km时,两类地震事件波形记录特征差异显著,通常爆破地震波形多显示为Pg振幅突出,垂直初动向上,Sg波不易识别,面波相对较发育等特征;在震中距大于120 km时,两类地震事件波形记录比较相似,不易直接通过波形记录进行判别,需进一步计算出地震波传播速度、持续时间等参数后才能判别。正确判定地震事件类型有助于提高大震速报和地震编目工作质量,能更好地为地震科研工作者提供准确的基础资料。

In this paper we analyze the characteristics of the artificial blasting and tectonic earthquakes in Lushan County,Sichuan Province.Different seismic phase characteristics of two types of earthquakes with different distances and similar seismic magnitude,and in different areas are explained with examples.Our study shows that when epicenter distance is lesser than 120 km,the characteristics differences between two types of seismic waveforms are obvious.In other words,the seismic waveforms produced by the blasting usually are obvious and the Pg wave amplitudes are highlighted.The direction of the seismic wave Pg onset is upward.The seismic wave Sg is not easy to recognize.The seismic surface waves are relatively developed well.When the epicenter distance is greater than 120 km,two types of seismic event waveform records are similar and is difficult to differ from each other.In order to recognize these seismic waves,we have to calculate further the seismic wave speed,the duration time.Correctly type determination can help us to improve the quality of earthquake catalog.