Citation

Papazachos BC. Nat. Hazards 1993; 7(3): 211-218.

Copyright

(Copyright © 1993, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1007/BF00662647

PMID

unavailable

Abstract

Repeat times of strong intermediate depth (60 km ≤h ≤ 180 km) earthquakes have been determined by the use of instrumental and historical data for six seismogenic sources in the Benioff zone of the southern Aegean area. For four of these sources, at least two interevent times (three mainshocks) are available for each source. By using the repeat times for these four sources, the following relation has been determined: logT t = 0.20M min + 0.19M p +a, whereT t is the repeat time (in years),M min the surface wave magnitude of the smallest earthquake considered,M p the magnitude of the preceding mainshock and 'a' parameter which varies from source to source. A multilinear correlation coefficient equal to 0.91 was determined for this relation, which indicates that the time predictable model holds to a satisfactory degree for the strong mainshocks of intermediate focal depth in the southern Aegean. By assuming that the ratioT/T t, whereT is the observed andT t the calculated repeat time, follows a lognormal distribution, the conditional probabilities for the occurrence of strong (M s ≥ 6.5) and very strong (M s ≥ 7.5) earthquakes during the period 1991-2001 in these four seismogenic sources have been calculated. These probabilities are very high (P > 0.9) for the strong and high (P > 0.5) for the very strong intermediate depth earthquakes which occur in the three sources of the shallower (h < 100 km) part of the Benioff zone where coupling occurs between the front parts of the Mediterranean lithosphere (downgoing) and the Aegean lithosphere.

Language: en