The International Seismological Summary

Abstract

THE International Seismological Summary for January, February and March, 1934, has just been received. Apart from individual studies of earthquakes it gives the final determinations of the epicentres and starting times of all earthquakes sufficiently recorded at seismological observatories to make such determinations reasonable. The criterion has now been made “three consistent observations of P and S to justify the determination. During the first quarter of 1934 there were 127 earthquakes whose epicentres were found; 47 of these were .new and 80 were repetitions from old epicentres, showing the tendency of earthquakes to recur in any one place where an earthquake had once happened. All except six of the earthquakes had a normal depth of focus. The six exceptions were all of deep focus. The deepest recorded earthquake during the quarter was on January 18, 1934, with a depth of focus of 0-09 of the earth's radius, or about 360 miles. Its epicentre was lat. 22° S., long. 180°, which is in the Pacific Ocean to the south of the Fiji Islands, a well-established zone for deep-focus earthquakes.