Aftershock locations and rupture characteristics of the 1995 Mariana deep earthquake

The August 23, 1995 (M_w = 7.0, depth 586 km) Mariana event produced one of the strongest deep earthquake aftershock sequences known. We combined teleseismic arrival times with arrival times picked from a local network operating directly above the event in the Mariana Islands, and relocated the main shock and aftershocks. We derived the source characteristics from teleseismic body waves by inverting waveform data of the Global Seismograph Network. The main shock ruptured downward across the entire width of the active slab along a plane dipping southwestward. Most of the 17 well-located aftershocks occurred along or very near the rupture plane. The different focal mechanisms of the main shock and aftershocks indicate that the stress field varies across the width of the Mariana slab at the area of the August 1995 sequence.