Sponsor: National Science Foundation

"This material is based upon work supported by the National Science Foundation under Grant No. 0331704."

"Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

(co-sponsors: Puerto Rico State Emergency Management Agency, Department of Marine Sciences at the University of Puerto Rico at Mayagüez, and the Sea Grant Program at the University of Puerto Rico)

Principal Investigators: 
Aurelio Mercado-Irizarry (Department of Marine Sciences, University of Puerto Rico at Mayagüez)
Philip L.-F. Liu (Department of Civil and Environmental Engineering, Cornell University)

Introduction

Because of its climate and natural beauty, the Caribbean region coastal population is growing at a very fast pace. Everyone who lives in this region is fully aware of the hurricane threat and is, to a great extent, prepared for dealing with the hurricane hazard. On the contrary, most of the people living in this region are not informed of what has been very nicely described as "the forgotten hazard", which is the tsunami. According to Lander et al. (2002), since 1498 there have been twenty-seven verified true tsunamis and an additional nine as "very likely true tsunamis". In the past 136 years there have been three destructive tsunamis in the northeastern Caribbean, the last one being in 1946.

In the Caribbean Sea region the potential sources for tsunami generation include earthquakes, sub-aerial and submarine landslides and underwater volcanic explosions. 

 According to Jansma and Mattioli (2003), Puerto Rico and the northern Virgin Islands sit within a broad zone of deformation between two larger plates: the North American to the north and the Caribbean to the south. This separate microplate moves approximately 15 mm/yr relative to North America and 3 mm/yr relative to the Caribbean. Offshore faults along which major earthquakes can occur have been identified in the boundary zone of the North American and Caribbean plates. All along the eastern Caribbean islands lies a subduction zone where the Caribbean plate slides under the North American plate, a potential source of tsunamigénico earthquakes. 

The landslide-tsunami threat in the Caribbean comes in part from the existence of the Puerto Rico Trench just north of the northeastern islands, along which, for example, there is evidence of a large slump with a potential volume of approximately 900-1500 km3 (Schwab et al., 1993; Grindlay, 1998), and many other smaller ones (ten Brink and Smith, 2003); smaller compared with the approximately 1000 km3 mentioned above, but still potentially large enough to cause extensive local damage. McAnn (2003) has identified potential submarine areas along the eastern Caribbean where slopes are sufficiently large so that the landslide hazard is considerable. There is also a landslide threat from the collapse of volcanic cones, especially along the eastern islands (Young, 2003). A good example is the Souffriere volcano in the island of Montserrat.

 Finally, the presence of the active submarine volcano, Kick’em Jenny, close to the islands of the southeastern Caribbean (just 10 km north of Grenada) is of much concern to the local governments. Past eruptions during the last century (1939, 1965) resulted in observed deep water tsunamis, with the one in 1939 being measured as 1 m high (http://www.uwichill.edu.bb/bnccde/grenada/grendoc/KickemJenny/kickemjenny.html). The concern is such that, for the first time (at least in the region), a banking institution (the Caribbean Development Bank) is funding a monitoring program of the volcano.