02399nas a2200217   4500000000100000000000100001008004100002260003300043653003600076100001500112700001700127700002400144700001900168700002200187245013300209856004800342300001200390490000700402520175800409020001402167       2004                            d  bSpringer Berlin / Heidelberg10aEarth and Environmental Science1 aKaren Hart1 aSteven Carey1 aHaraldur Sigurdsson1 aStephen Sparks1 aRichard Robertson00aDischarge of pyroclastic flows into the sea during the 1996\textendash1998 eruptions of the Soufrière Hills volcano, Montserrat  uhttp://dx.doi.org/10.1007/s00445-004-0342-1  a599-6140 v663 aExplosive eruptions of the Soufrière Hills volcano on the island of Montserrat in the West Indies generated pyroclastic flows that reached the sea on the east and southwest coasts between November 1995 and July 1998. Discharge of the flows produced two pyroclastic deltas off of the Tar and White River valleys. A marine geological survey was conducted in July 1998 to study the submarine extensions of both deltas. Detailed profiles of depth and sub-bottom structure were obtained using a CHIRP II/bubble pulser system. These profiles were compared with pre-eruption bathymetric data in order to identify areas of recent deposition and erosion. Deposition off the Tar and White River valleys was thickest nearest the coastline and deltas, and extended into deeper water up to 5 km from shore. The total volume of submarine pyroclastic deposits as of July 1998 was 73\texttimes10 6 m 3 DRE. Submarine pyroclastic deposits off the Tar River valley made up more than two-thirds of the total volume (55\texttimes10 6 m 3 DRE) and covered an area of approximately 5.0 km 2 , which included the delta. The volume of submarine pyroclastic deposits in the White River area (18\texttimes10 6 m 3 DRE) is probably underestimated due to the lack of precise pre-eruption bathymetric data in areas greater than 2 km from shore. Growth of pyroclastic deltas at the mouths of the Tar and White River valleys continued to the edge of the submarine shelf where there was a steep break in slope. In the Tar River area pyroclastic material was distributed down the steep shelf break and into deeper water at least a few kilometers from shore. The material spread out radially, forming a submarine fan, where distribution was primarily controlled by bathymetry and slope.  a0258-8900