POSSIBLE EXISTENCE OF AN UNIDENTIFIED, SEISMOGENIC FAULT ZONE ALONG THE SOUTHERN COAST OF JAMAICA: A COMPILATION OF EARTHQUAKE AND REMOTE SENSING DATA

We have compiled a GIS database for south-central Jamaica that includes a digital elevation model, geologic map, LANDSAT imagery, and earthquake focal mechanisms. This combined data set demonstrates the regional importance of the 150-km-long South Coast fault system in accommodating interplate motion and controlling the geomorphology, coastline, and geologic exposures of this part of the island. The South Coast fault forms a prominent, 600-m-high cliff in late Tertiary limestone in the area between Alligator Pond and Rocky Point where it extends offshore into the Walton basin and Nicaraguan Rise. Satellite imagery shows that the fault forms a prominent lineament with a 1.3-km left-lateral offset of the modern channel of the Rio Minho. The fault also localizes an anomalous topographic and structural feature, the Round Hill anticline. To the east the fault extends into Kingston bay where it projects to the area of the Palisadoes peninsula, site of the 1692 Port Royal earthquake and tsunami. Most active fault displacements in Jamaica have been assumed to occur in a large right-stepping restraining bend with the South Coast fault area being part of the stable (Caribbean) side of the bend. These data, along with GPS data in progress (DeMets et al.) show that the bend structure may be in the process of being bypassed by active motion on the South Coast fault zone.