Fig. 13
From: Earthquakes in Switzerland and surrounding regions during 2012
Displacement seismograms of the Vallorcine events of 2005/09/08 (ML 3.0) and 2012/10/25 (ML 3.6) recorded at stations AIGLE (EW-component, 35 km epicentral distance) and TORNY (Z-component, 82 km epicentral distance). To stabilize the integration and to accentuate differences at high frequency, the signals are filtered with a 1 Hz, 4th order, zero-phase Butterworth high-pass filter and an 8 Hz, 2nd order Butterworth low-pass filter. Because the Pg onsets at TORNY are rather emergent, both sets of seismograms are aligned on the Pg arrival at station AIGLE. Note the high signal similarity as well as the almost identical Sg–Pg arrival-time differences at AIGLE and PmP–Pg arrival-time differences at TORNY for the two events. These similarities are evidence of similar focal mechanisms and almost identical epicenters and focal depths