Bulletin of the Seismological Society of America; October 2003; v. 93; no. 5;
p. 2082-2088; DOI: 10.1785/0120020163
© 2003 Seismological Society of America
The Maximum Likelihood Estimator of b-Value for Mainshocks
Anna Maria Lombardi
Istituto Nazionale di Geofisica e Vulcanologia, Roma
via di Vigna Murata, 605
00143 Roma, Italy
lombardi{at}ingv.it
Considering the magnitudes of events in a catalog as independent and
exponentially distributed random variables, in agreement with the
GutenbergRichter law, the statistical significance of the difference
between the maximum likelihood estimators of the b-value for
mainshocks (bms) and for all events
(ball) is discussed. It is shown that, as a consequence of
their definition, the mainshocks do not entirely satisfy the
GutenbergRichter law and that bms has been
frequently estimated as lower than ball because of an
incorrect use of the maximum likelihood method.
Copyright © 2009 by Seismological Society of America