Southeastern Caribbean sea level variability and viscoelastic relaxation

Viscoelastic modeling of earthquakes in the southeast Caribbean shows that distant dip-slip earthquakes in the Lesser Antilles and the geometry of the subduction zone play a significant role in vertical deformation observed along the southern Caribbean plate margin. We find that dip-slip earthquakes yield vertical displacements that are 1-2 orders of magnitude greater than those generated by strike-slip earthquakes along the Caribbean-South American plate boundary. In addition, postseismic vertical displacements are at least as great or greater at distances of several hundred kilometers than the coseismic counterpart depending upon the geometry of the source. Tide gage data from Venezuela suggest that these vertical displacement rates may still be observed several decades after the occurrence of large subduction zone earthquakes (Ms 7 or greater). In addition, the uplift rate observed at the tide gages largely follows the anticipated flexure of die Caribbean plate due to the subduction process.