Construction and destruction of Mont Pelee volcano: Volumes and rates constrained from a geomorphological model of evolution

Abstract

International audienceThis study presents long-term volumes and construction rates for the Mont Conil-Mont Pelée volcano and rate estimates at which volcanic activity creates relief. An algorithm, ShapeVolc, is used to numerically model topographic surfaces. Volcano morphology is analyzed using current digital elevation model in combination with mapped geology to produce 10 paleotopographies at the end of four constructional stages and three destructional events. Volumes of each constructional stage were estimated at about 35.2 km3, 26.2 km3, 8.3 km3, and 2.5 km3 for a total cumulative erupted volume of 72.2 km3. We estimate that Mont Pelée accounted for about 10% of the Lesser Antilles arc production in the last 100 kyr. The volcano has been built at an average rate of 0.13 km3/kyr during the last 550 kyr. During that time, construction rates varied by a factor of 15, from 0.04 km3/kyr in early stages up to 0.52 km3/kyr after the second flank collapse. Volumes displaced by each flank collapse were estimated at 14.7 km3, 8.8 km3, and 3.5 km3, thus about 37% of the total constructed volume. Integrated over the volcano's lifetime, the rate at which flank collapses removed material off the island is 0.15 km3/kyr. In contrast, long-term erosion rates outside collapsed areas are estimated at about 0.05 ± 0.7 km3/kyr, or ~11 km3 of material removed. This latter rate is not negligible, which strengthens the importance of taking into account recurrent small erosional events on the geomorphological evolution of a volcanic island in a tropical context