Tsunami generation potential of different tsunamigenic regions in the Pacific

The historical tsunami catalog collected within the Historical Tsunami Database (HTDB)/PAC Project contains the most complete parametric tsunami data covering the whole Pacific and the full historical period of the available observations (from 47 BC to present). The collected data provide a possibility to study variability of the tsunami potential of submarine earthquakes over the main tsunamigenic regions in the Pacific. For each region, the tsunami efficiency (TE) is calculated as the ratio between the number of tsunamis of tectonic, landslide and unknown origin and the total number of the coastal and the submarine earthquakes with magnitude M≥7.0 and focus depth h<100 km. The tsunami efficiency, calculated in the above manner, varies from 84% for the South America region to 36% for the New Zealand-Tonga region. The correlation of variability of the TE value with the position of the main sedimentation zones in the Pacific shows that the regions located within the equatorial humid zone (New Guinea, Indonesia, Philippines) have a larger TE value as compared to the regions located in other zones. The circum-continental zoning in the sedimentation rate has resulted in the highest TE value for the South America region, where tsunamigenic sources are located close to the land. A higher sedimentation rate results in a higher potential for submarine slumping, which, according to the results of many recent studies, considerably increases efficiency of tsunami generation mechanism. Earthquakes in the marginal seas (the Japan Sea, the Okhotsk Sea, the Bering Sea) have a higher tsunami efficiency as compared to the earthquakes in the Pacific Ocean. A similar feature takes place for the Indonesia region, where the tsunami efficiency of the earthquakes occurring in the Indian Ocean (within the Java trench) is almost 95%, while the rest of the region has this value at the level of 62%.