Lg magnitudes and yield estimates for underground Novaya Zemlya nuclear explosions

Abstract Lg -wave amplitudes of 30 Novaya Zemlya underground nuclear explosions, as recorded by short-period seismographs in Denmark, Finland, Germany, Norway, Spitsbergen, and Sweden, are used to determine m b ( Lg ) values. Assuming that the m b ( Lg ) versus explosion yield relation derived from Nevada Test Site data applies to all continental areas, the yields of the explosions are estimated. They cover a large range of values, from 2.5 to 4900 kt. The largest explosion since April 1976 had an estimated yield of 145 kt . The m b ( Lg ) values, when subtracted from the m b ( P ) values, can be used to estimate the m b ( P ) bias between two test sites. In this way, the m b ( P ) bias between Novaya Zemlya and the Nevada Test Site is estimated to be 0.20 magnitude units .