However, in the definition of magnitude the ground-motion amplitude is corrected for
epicentral distance and converted to a focal characteristic.Iso seismal maps showing the regional distribution of damage give the maximum intensity (Imax)experienced in
an earthquake, which, although influenced by the geographic patterns of population and settlement, is usually near to the epicenter. A moderately strong, shallow-focus
earthquake under a heavily populated area can result in higher intensities than a large deep focus earthquake under a wilderness area (compare, for example, the death tolls for
the 1960 Agadir magnitude 5.7 and 1964 Alaskan magnitude 9.2 earthquakes in Table 3.2). However, for earthquakes with focal depth h50 km the dependence of Imax
on the focal depth can be taken into account, and it is possible to relate the maximum intensity to the magnitude with an empirical equation (Karnik, 1969)
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