A Comparative Study of the Elastic Wave Radiation from Earthquakes and Underground Earthquakes and Underground Explosions

摘要

A detailed analysis of the surface wave radiation from two underground explosions (BILBY and SHOAL) and an earthquake (near Fallon, Nevada) whose epicenter is only 60 km from SHOAL indicates that: at long periods the surface wave radiation from the earthquake can be explained by a pure quadrupole (double-couple) source, but a higher frequencies the radiation pattern shows asymmetries which suggest effects due to rupture propagation which require higher-order multipole terms in the source equivalent representation; the surface waves from the explosions can be explained by superposed monopole and quadrupole sources, with no indication of higher-order multipole terms; A principal conclusion of the study is that the anomalous radiation from explosions is due to stress relaxation around the shock-generated shatter zone and not due to earthquake triggering. (Author)