Aftershock sequences of some large earthquakes in the region of Greece

摘要

Deformation characteristics, magnitude and time distribution
of the aftershocks of the large earthquakes, occurred in the region
of Greece from 1926 till 1964 are investigated. An approximate relation
between the number of aftershocks and the magnitude and focal depth
of the main shock has been found. Also, an approximate relation has been
derived between the magnitude of the largest aftershock and the magnitude
and focal depth of the main sliok. The largest aftershock occurs within
fourteen days after the main shock. In many cases large " late aftershocks "
occur one or more months after the main shock. One or more foreshocks
of magnitude larger than 3.5 occurred in forty per cent of the cases. The probability for an earthquake to be preceded ly a large foreshoek not much
smaller than the main shock is 10%. It is shown that some properties of
the Earth's material in the aftershock region can be derived by studying the
magnitude distribution and deformation characteristics of the aftershocks.