Frequency dependent energy and magnitude of earthquakes and underground nuclear explosions

The energy and magnitude are examined as a function of frequency for both shallow natural earthquakes and underground nuclear explosions which occurred in different regions of USSR and China from 1973 to 1975. The selected events were recorded by the high sensitive short-period seismographs equipped with twelve different frequency channels which are installed at Helwan Observatory. The majority of the events have body wave magnitude from 5.2 to 6.3. The frequency band used in this study is from 0.448 to 2.24 Hz. It appears that energy and magnitude characteristics of seismic waves generated by earthquakes and underground nuclear explosions can be used for discrimination between these two types of seismic sources. (author)