The earthquake history in a fault zone tells us almost nothing about mmax

Abstract:

In the present study, we summarize and evaluate the endeavors from recent
years to estimate the maximum possible earthquake magnitude m_max from observed data. In
particular, we use basic and physically motivated assumptions in order to identify ``best cases'' and ``worst cases'' in terms of
lowest and highest degree of uncertainty of m_max. We demonstrate in a
general framework that earthquake data and earthquake proxy data recorded in a fault zone, provide
almost no information about m_max, unless numerous seismic cycles are
supported by reliable and homogeneous data. Even if detailed earthquake information from some
centuries including historic and paleo-earthquakes are available, only very few,
namely the largest events will contribute at all to the estimation of m_max and result in
unacceptable high uncertainties. As a consequence, estimators of m_max
in a fault zone, which are based solely on earthquake-related information from this
region, have to be dismissed.