Notes on a Map of the 1961-2010 Eruptions of Volcán de Pacaya, Guatemala
Ruben Otoniel Matías Gomez, William I. Rose, José Luis Palma, and Rüdiger Escobar-Wolf
Area: Volcán de Pacaya, Guatemala
Scale: 1:10,000 for a paper printing size A0 (841 mm x 1189 mm) for Appendices C and D
Resolution: 300 dpi for raster data sets imbedded in the map, at the 1:10,000 printing scale
Projection: Guatemala Transverse Mercator (GTM)
Parameters: False Easting 500000. False Northing 0. Central Meridian -90.5. Scale Factor 0.9998. Latitude of Origin 0. Datum: WGS 1984.
Units: Labeled contour interval 100 m. Intermediate contour interval 20 m. Elevation values in meters above sea level.
Precision: Map precisions has not been assessed for the geologic units and vent locations.
Description: The Pacaya volcanic complex is part of the Central America volcanic arc, which is associated with the subduction of the Cocos plate under the Caribbean plate. Located on the southern rim of the Amatitlán Caldera, this complex includes the Pacaya composite cone, Cerro Grande and Cerro Chiquito, and the Cerro Chino scoria cone. These eruptive centers have been active during the Quaternary and have produced olivine-bearing basaltic lavas; pyroxene andesites, dacites and rhyodacites; and associated pyroclastic products. The volcanism at Pacaya has been strongly episodic, with eruptive intervals lasting 100 to more than 300 yr, and quiescent periods lasting typically between 300 and 500 yr. 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 field observations. The information consists of a total of 249 lava flow units, six pyroclastic flow units, two scoria-fall units, two undivided pyroclastic units (proximal and distal), one aeolian sediments unit, and one alluvium unit, all of which are defined as polygons in the GIS. A total of 349 eruptive vents associated with flow units were also identified and defined as points in the GIS. Altogether, this unique data set documents the 50 year-long effusive and explosive activity associated with the growth of a basaltic stratocone.
Exported Coverages (Appendix E): The GIS_shapefile_and_ArcMap_mxd_files.zip file contains two main folders: "ArcMap_document_mxd_files" and "shapefiles". Within the "shapefiles" folder are folders "geologic_units", "other_shapefiles", and "vents". In the /shapes directory, all of the coverages are exported as ArcView shape files. Each file therefore has a .dbf, .prj, .sbn, .shp, and .shx file associated with it. You will have to copy all of these.
- 5 MB Notes File that Accompanies Maps (.pdf)
- 96 MB APPENDICES A and B: (A) Excel spreadsheet with the label of the unit, dimensions (length, area, thickness, volume), and mean volume flow rate of all lava flows; and (B) Excel spreadsheet with the location and activity date of all the eruptive vents. (.xls)
- 41.3 MB APPENDICES C and D: (C) Complete map with the 1961-2010 activity; and (D) seven maps showing the deposits in different periods: D.1. 1961-1969, D.2. 1970-1979, D.3. 1980-1984, D.4. 1985-1989, D.5. 1990-1994, D.6. 1995-1999, D.7. 2000, and D.8. 1961-2010. (.pdf)
- 19.5 MB APPENDIX E: Multiple GIS files in ArcGIS (ESRI) format, including all the mapped units and vents (shapefiles) and the final map documents (.mxd files), grouped in a single .zip file.
- 9.3 MB APPENDIX F: Video file in .wmv format showing the progressive emplacement of lava flows and vent openings throughout the 1961-2010 period on Pacaya volcano. (.wmv)