A waveform similarity approach to investigate seismicity patterns

the temporal and spatial evolution of seismicity, a simple cross-correlatio n technique was applied to a waveform data set of western Alps earthquakes. A selection of events recorded by a reference station of the regional seis mic network of North-Western Italy (IGG network) within a particular S-P ra nge was used. The adopted method was tested on 380 events recorded in 1995, allowing for the definition of the critical parameters for an optimal iden tification of earthquake families. The comparison of the individuated families definition with the relevant ep icentres map confirms that, on small scales, the epicentre positions of mic roearthquakes located by a regional network could be strongly influenced by location errors. The analysis was extended to a more complete data set of 2653 events; 1171 of them were grouped in families. The results demonstrate d that our single station method is able to discriminate between closely sp aced families on the basis of the position and of the radiation properties.