SCIENCE OF TSUNAMI HAZARDS THE SPATIAL-TEMPORAL DISTRIBUTIONS OF THE TSUNAMIGENIC EARTHQUAKE SOURCES
Journal of Tsunami Society International
The spatial-temporal periodicity and occurrence of tsunamigenic earthquakes continue to be one of the still unsolved fundamental problems that also may have great practical operational importance. Thus, for the present investigation, we used data of tsunamigenic earthquakes (TEQ) of the last 120 years. All of the TEQ events with tectonic origin and magnitude M≥7.5, intensity of tsunami I>=1, and validity of event V=4, were selected in a working catalog which was prepared on the basis of the
... rt Tsunami Data Base for the Pacific, and the Tsunami Event and Runup Database of NOAA. The total number of chosen events for the study, was 99. For these events, we analyzed the spatial and spatial-temporal distributions of the TEQ density and of released energy separately for the entire Earth, the Northern and Southern hemispheres, and for several regions of the Pacific Basin (Aleutian Islands, Kuril Islands, the equatorial belt and Central America and South America). The analysis of distribution of the TEQ in time, reveals a sharp increase in activity (density of events and of released energy) in the early 20th and 21st centuries. However, the most complete benefit of the study was the determination of the two-dimensional distribution of events (in latitudes and in time). The analysis revealed periodic changes of TEQ activity in different time intervals. The intensification of tsunami activity appears to have different periodicity at various latitudinal belts. We determined that tsunami sources are located basically in three latitudinal intervals: 40°N-60°N, 15°N-10°S and 25°S-35°S. The periodicity of tsunami activity varied from 10 to 50 years.