A database of geologic units emplaced during the eruptions of the Volcán de Pacaya, Guatemala, from 1961 to 2010, has been compiled in a geographic information system (GIS). The mapping of the units is based on integrating information from aerial photographs, satellite images, and detailed fi eld observations. The information consists of a total of 249 lava fl ow units, six pyroclastic fl ow units, two scoria-fall units, two undivided pyroclastic units (proximal and distal), one aeolian sediments unit, and one alluvium unit, all of which are defi ned as polygons in the GIS. A total of 349 eruptive vents associated with fl ow units were also identifi ed and defi ned as points in the GIS. Volumes were calculated for all lava fl ows, yielding a cumulative volume of 0.078 km3 (not corrected for density). The volumes of four tephra deposits related to explosive events during this period were also calculated, and yielded values of the order of 106 to >107 m3 each. Geochemical data of 69 samples of lava show that the composition of erupted products did not change systematically, with SiO2 ranging from 50 to 52.5 wt%. The GIS information is organized in geologic units, coded by date of emplacement between 1961 and 2010, and is presented in eight geologic maps, showing the units exposed at the surface at different intervals of time. Altogether, this unique data set documents the 50-yr-long effusive and explosive activity associated with the growth of a basaltic stratocone. These data can be used, for instance, to study the morphological aspects of cone building at polygenetic volcanoes, and the behavior of lava fl ows.
Available at: http://works.bepress.com/william-rose/11/