Caribbean tsunami and earthquake hazards studies

Sketches of the proposed model. (a) North-south cross-section at the longitude of Puerto Rico showing the change in slab dip and topography from their initial profile (dashed lines) to their present profile (solid lines). Solid and dotted lines denote present and initial asthenospheric corner flow due to subduction. A flow from the underside of the subducting plate through a gap between the two segments through a gap between the two segments. (b) 3-D view to the NE of the subducting North American oceanic plate and the thicker Bahamas crust beneath the NE corner of the Caribbean plate. The island Puerto Rico (P.R.) and the Virgin Islands (V.I.) are shown schematically. Orange arrows denote tensile stresses due to the curvature of the subducting slab and tensile stress due to the subduction of Main Ridge. Note the steeper dip of the slab under Puerto Rico relative to under the Virgin Islands. The nature of the boundary between the two slab segments is unknown and is represented here as a sharp cut for simplicity. Grey arrow - A possible asthenospheric flow through a gap between the two slab-segments from the underside of the subducting plate into the corner between the subducting and overlying plate. Thin dashed line - The PRT. Black arrow - Relative direction of plate motion.