Volcanic hazard from San Martin Tuxtla Volcano, Tuxtla Volcanic Field, Veracruz, México: probability maps of ashfall deposition from possible future eruption

Abstract

San Martin Tuxtla Volcano, the largest and highest edifice in the Tuxtla Volcanic Field, had explosive eruptions in 1664 and 1793. This volcano poses the highest hazard for the growing population centers surrounding it. The impacts and deposits of the 1793 eruption have been studied recently, and some of its characteristics, such as eruptive mass, grain-size distribution of the products and plume height, have been estimated. These data, together with daily data on wind velocities taken in the nearby city of Veracruz, have been used to conduct numerical modeling of ash distribution from an eruptive column comparable to that estimated during the 1793 event. Using wind velocities of randomly chosen days, we constructed probability maps of areas likely to receive, at least 1, 5, or 10 cm of ash. Our results indicate that an area about 1.3 9 10 4 km 2 has a 12% probability of being covered by an ash fall more than 1 cm thick, if a mass of 10 14 g was erupted and deposited from a 10-km-high eruptive plume. The results presented in this paper serve as a scientific basis to estimate volcano risk in the area from a possible eruption, consisting of one or several large explosive events, at San Martin Tuxtla volcano.