Discrimination between explosions，mine collapsesand earthquakes in capital region of China

Choosing seismic data of explosions，collapses and earthquakes with ML in the range of 2.0mdash;2.2 during August 2008 to September 2009 in capital region，and analyzing and comparing the data in time and frequency domain，this paper studies how to identify the explosion，mine collapse and earthquake. In time domain，vertical component first motion of explosion seismic records is upward，and that of mine collapses is downward，while that of earthquakes depends on station distribution. The surface wave of explosion and mine collapse develops well. The S to P wave amplitude ratio (AS/AP) of earthquakes are larger than that of explosions and collapses. Moreover，energy attenuation of explosions and collapses is faster than that of earthquakes. In frequency domain the energy attenuation of high frequency wave is faster than that of low frequency one. For the events with similar magnitude，the corner frequencies of amplitude spectrum for earthquakes are the highest，and that for explosions are secondary high，while the corner frequencies for mine collapses are the lowest. When epicenter distance is smaller than 200 km，the peak frequencies of explosion amplitude spectrum are mainly 5mdash;7 Hz，and that of collapses are 2mdash;4 Hz，while the peak frequencies of earthquakes are high in the range of 10mdash;18 Hz. The wave frequency range of earthquakes is the widest，and that of explosions and collapses are next-wide.