| New evidence has emerged that the plate boundary between the Caribbean and North America plates is undergoing a major change due to plate breaking in at least one location, near Puerto Rico. Preliminary results (available in this project) show unusually high seismic activity near this tear. How and why plate tearing occurs is not understood. Similar active transitional processes in plate tectonics can only be studied in a few locations around the world. We propose to exploit this opportunity and investigate the current geodynamics of the northern Caribbean region, 1) because the mechanisms involved are only poorly understood, 2) because the potential for earthquakes and tsunamis can only be fully assessed in light of the dramatic consequences of such plate tearing, and 3) because similar transitional aspects of plate tectonics likely played a prominent role in the historical evolution of the geology of the Caribbean and in other regions (e.g., the Mediterranean and Carpathians). Using state-of-the-art quantitative geodynamic models we aim to integrate a wide range of observations (geometric, kinematic, and dynamic) in a physically plausible way. A pivotal role will be played by new results of high-resolution P-travel time tomography that discovered a-seismic slabs in the regional upper mantle, i.e., which were invisible before. We can therefore now start to establish how sinking slabs in the upper mantle drive deformation in the north Caribbean plate boundary zone. Seeking these depth-to-surface relations on time scales of natural hazards to that of many earthquake cycles, we aim to incorporate the growing GPS data set to 1) explain current crustal block motions in the plate boundary zone, 2) find and understand the repetition time scales of plate breaking events, 3) to assess the potential hazard of offshore faults and deeper crustal faults, both of which are not monitored by GPS. Finally, we seek to identify whether on geological time scales the evolution of the north Caribbean plate boundary can be understood as a succession of slab-related events as happen today. |
