Magnitude-Frequency Distribution in the European-Mediterranean Earthquake Regions -- Comment

Yan Y. Kagan

Published May 1995, SCEC Contribution #184

Karnik and Klima (1993a, hereafter referred to as K&K) recently published a statistical analysis of the European-Mediterranean 1901-1985 earthquake catalog compiled by V. Karnik. (The first part of the catalog was published by Karnik in 1969). The catalog which contains over 13,000 events, presents a unique possibility to test whether the Gutenberg-Richter (GR) formula for the distribution of earthquake sizes is applicable, not only for large provinces but also for relatively limited regions comprising geologically known faults and fault segments. The characteristic earthquake hypothesis proposed recently, states that the earthquake size distribution for specific faults and fault segments is significantly different, especially for large earthquakes, from what the GR relation predicts (Schwartz and Coppersmith, 1984; Davison and Scholz, 1985). If this hypothesis is true, it has several important implications both for understanding the physics of earthquake sources and for evaluation of seismic risk for specific earthquake zones. However, it can be shown that the statistical tests of the characteristic earthquake hypothesis carried out so far, have significant flaws (Kagan, 1993): they are either based on a limited sample of seismicity, thus liable to possibility of a biased sampling, or they use questionable statistical reasoning. The European- Mediterranean 1901-1985 catalog covers a large area over a significant span of time, and across a broad magnitude range, thus the characteristic hypothesis can be tested by using standard statistical methods.

Kagan, Y. Y. (1995). Magnitude-Frequency Distribution in the European-Mediterranean Earthquake Regions -- Comment. Tectonophysics, 245(1-2), 101-110. doi: 10.1016/0040-1951(94)00129-W.