Precursory activation of seismicity in advance of the Kobe, 1995, M=7.2 earthquake

A succession of precursory changes of seismicity characteristic to earthqua kes of magnitude 7.0-7.5 occurred in advance of the Kobe 1995, M = 7.2, ear thquake. Using the Japan Meteorological Agency (JMA) regional catalog of ea rthquakes, the M8 prediction algorithm (KEILISBOROK and KOSSOKOV, 1987) rec ognizes the time of increased probability, TIP, for an earthquake with magn itude 7.0-7.5 from July 1991 through June 1996. The prediction is limited t o a circle of 280-km radius centered at 33.5 degrees N, 133.75 degrees E. T he broad area of intermediate-term precursory rise of activity encompasses a 175 by 175-km square, where the sequence of earthquakes exhibited a speci fic intermittent behavior. The square is outlined as the second-approximati on reduced area of alarm by the "Mendocino Scenario" algorithm, MSc (KOSSOB OKOV et ai., 1990). Moreover, since the M8 alarm starts, there were no swar ms recorded except the one on 9-26 Nov. 1994, located at 34.9 degrees N, 13 5.4 degrees E. Time, location, and magnitude of the 1995 Kobe earthquake fu lfill the M8-MSc predictions. Its aftershock zone ruptured the 54-km segmen t of the fault zone marked by the swarm, directly in the corner of the redu ced alarm area. The Kobe 1995 epicenter is less than 50 Lm from the swarm a nd it coincides with the epicenter of the BI 3.5 foreshock which took place 11 hours in advance.