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Dominican Republic

Location: Southern Coast, Dominican Republic

Type of Project: Tsunami Hazard Analysis

Client: Sandwell Engineering, Vancouver Canada

ASR Projects- Dominican Republic

The regional tectonics around the Dominican Republic. The black lines are primary fault lines and the red ovals indicate the approximate rupture area for each of the earthquakes indicated. The black star indicates the location of the study site.

Project Overview:

A tsunami hazard study was required as part of an overall seismic hazard analysis for a proposed power plant to be built at a site on the southern coast of the Dominican Republic. The client wished to understand the 100-year tsunami hazard in relation to other hazards such as storm surges from hurricanes.

Project Outcomes:

Initially, the client assumed that hurricane storm surge would dominate over tsunamis in terms hazard levels over next 100 years. However once historical records and the available literature were examined in more detail, this assumption was called into question.

The region around the study site has suffered more than 10 tsunami events in the past 250 years, with an average recurrence interval of 26 years and actual recurrence intervals ranging from 0 to 72 years between events. The study site itself lies near a tectonic triple junction (a point where two fault lines meet) and experienced a devastating earthquake and tsunami in 1751.

Published results of a probabilistic seismic hazard study for the region suggest recurrence intervals for large earthquakes on faults near the study site are between 233 and 675 years. When one considers that the last such event was 257 years ago (1751), the threat of a tsunamigenic earthquake in this region becomes clear. Earthquake scaling relationships and known slip rates for nearby faults suggest a repeat of the 1751 event could happen every 382 years implying that as little as 125 years remain before another great earthquake in this region.

Our study therefore concluded that a large earthquake capable of producing a tsunami (Mw > 7.5) could be expected in the next 400 years with the distinct possibility based on historical and geological arguments that such an event could happen in the next century.

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