maximum trace amplitude, mm, as recorded by a standard Wood-Anderson
seismograph that has a natural period of 0.8 s, a damping factor of 80%, and a
static magnification of 2800. The maximum trace amplitude must be that amplitude
that would be recorded if a Wood-Anderson seismograph were located on firm ground at a distance of exactly 100 km (62 mi) from the epicenter
of the earthquake. Charts and tables are available to adjust the maximum
trace amplitude for the usual case where the seismograph is not located exactly
100 km (62 mi) from the epicenter.