Spatiotemporal distributions of tsunami sources and discovered periodicities

Abstract

Both spatial and spatiotemporal distributions of the sources of tsunamigenic earthquakes of tec tonic origin over the last 112 years have been analyzed. This analysis has been made using tsunami databases published by the Institute of Computational Mathematics and Mathematical Geophysics (Siberian Branch, Russian Academy of Sciences) and the National Aeronautics and Space Administration (United States), as well as earthquake catalogs published by the National Earthquake Information Center (United States). It has been found that the pronounced activation of seismic processes and an increase in the total energy of tsuna migenic earthquakes were observed at the beginning of both the 20th (1905)(1906)(1907)(1908)(1909)(1910)(1911)(1912)(1913)(1914)(1915)(1916)(1917)(1918)(1919)(1920) and 21st (2004-2011) cen turies. Studying the spatiotemporal periodicity of such events on the basis of an analysis of the two dimen sional distributions of the sources of tectonic tsunamis has made it possible to determine localized latitudinal zones with a total lack of such events (90°-75° N, 45°-90° S, and 35°-25° N) and regions with a periodic occurrence of tsunamis mainly within the middle (65°-35° N and 25°-40° S) and subequatorial (15° N-20° S) latitudes of the Northern and Southern hemispheres. The objective of this work is to analyze the spatiotem poral distributions of sources of tsunamigenic earthquakes and the effect of the periodic occurrence of such events on the basis of data taken from global tsunami catalogs.