Marine Geoscience Investigations off the Former Danish West Indies – Plate Tectonics and Earthquakes, Hurricanes, and Ocean Circulation Changes

Seniorforsker, PhD Antoon Kuijpers, Geological Survey of Denmark and Greenland (GEUS)

The history of the northeast Caribbean Danish West Indies (DWI) is known for passage of numerous hurricanes and repeated occurrence of tsunamis causing great damage to human life and buildings. Strong earthquakes associated with collision of the Caribbean and North American Plate led to several disastrous tsunamis as, for instance, in November 1867, when ships anchoring off Charlotte Amalie (St. Thomas) were wrecked and numerous people killed. Severe tropical cyclones (hurricanes) have their origin in areas of the tropical Atlantic where sea surface temperature (SST) exceeds 27^o C. They typically occur in the period July to October, and their frequency depends, apart from SST, also on large-scale atmospheric circulation patterns. The warm ocean waters of the northeast Caribbean region are the prime source of the Gulfstream and North Atlantic Current responsible for the generally mild northwest European winter climate. Oceanographically important in the DWI area is the up to c. 4800 m deep Anegada-Jungfern Passage which forms a conduct for deep water exchange between the North Atlantic and deep Caribbean. Colder subsurface water masses from the Southern Hemisphere (Antarctic Intermediate Water) are also found here. With seismic and acoustic methods and sediment core records to explore the  geological history supplied by hydrographic measurements the main objective of the project is 1) to improve our knowledge of regional plate tectonic setting and sediment stability (tsunami risk), and 2) to trace possible links between oceanographic changes and North Atlantic (e.g. hurricane) climate variability with the ultimate aim of better understanding possible influences of the tropical Atlantic on high-latitude climate.