This study is based on earthquakes reported on the Preliminary Determination of Epicenter (P.D.E.) cards of the Coast and Geodetic Survey. Four types of presentations are made: (1) a chronological list of earthquakes: (2) a magnitude map showing the geographical distribution of earthquakes whose magnitudes are greater than, or equal to, 3.0; (3) a presentation of frequency versus magnitude for the total United States for and individual regions of high seismicity; and (4) a 'seismicity' map giving a quantitative measure of relative seismic activity.