Aftershock Analysis for the 1997 Ghaen-Birjand (Ardekul) Earthquake

Document Type : Seismology and Engineering Seismology



2 Seismology Department of NORSAR

3 Head of NORSAR Seismology Department


In this study at the first step, the database of two temporary networks of International Institute of Earthquake Engineering and Seismology (IIEES) and Institute of Geophysics of Tehran University (IGTU), which deployed independently after the Ghaen-Birjand earthquake, were merged. Based on the new database, focal mechanisms of some larger aftershocks were obtained and crustal model of eastern Iran [3] modified for the epicentral area of Ghaen-Birjand earthquake and its aftershocks. The Vp/Vs ratio is inferred as 1.85 for the region covered by the temporary seismic networks. After relocation of more than two hundred events, it was cleared that at least three of the largest aftershocks were estimated to be located with a precision corresponding to error ellipsoid axes within 5 to 10 km (Ground Truth level of 5 to 10).