Spatial patterns of earthquake sounds and seismic source geometry

Earthquake sounds are heard during or immediately before an event up to sev eral kilometres around the epicentral area. Sound data as heard by people h ave been collected by way of macroseismic questionnaires, showing that soun d audibility does not follow isotropic patterns. The explanation of this ef fect is found in the behaviour of the particular radiation pattern of the P -waves for each earthquake, in connection with its focal mechanism. This re sult opens the possibility to get more information about the earthquake sou rce parameters in the future and past events, making use of non-instrumenta l observations.