Evaluation of the detection and location capability of IMS for seismic events occurred in US Nevada

A comparison study between the Seismic Event Bulletin produced by ANSS and IDC was carried out to evaluate the detection and location capability of IMS for seismic events occurred in Nevada, USA, and the main factors affecting the detection were analyzed. The result shows that IMS can detect minimum earthquakes of mb2.1 occurring in Nevada. IMS can detect all events of M4.5. More than 80% of M4.0 events in ANSS SEB are also detected by IMS. The epicenters determined by IDC are averagely about 13.6 kilometers away from the epicenters determined by the ANSS using local/regional seismic station networks, with the largest deviation of 82 km. Comparing different magnitudes of the same events shows that there is a linear relationship between the body wave magnitude mb determined by IDC and M determined by ANSS. Furthermore， the former is averagely lower than the latter by about 0.2 magnitude unit. The factors that may contribute to the relative location deviation were statistically studied. The result suggested that number of defining phases and azimuth gap in IDC REB contributes most to this relative deviation， but the minimum event-station distance has little effect on relative deviation.