Collection of a High-Resolution Spatial and Ground-Based Dataset From the 2010 Explosive Events at Merapi Volcano, Java, Indonesia

University Of South Florida, Tampa FL

Investigators

Abstract

This project is supported by the Petrology and Geochemistry program (Division of Earth Sciences, Directorate of Geosciences) in cooperation with the Office of International Science and Engineering. Merapi Volcano, located in heavily populated Central Java, is one of Indonesia's most active and dangerous volcanoes. After four years of quiescence, an eruption began on 26 October 2010 that was characterized by explosions along with pyroclastic density current (PDCs) that traveled to the western and southern sectors of the volcano. Reports on 27 October noted that about 35 people died and several were injured. Explosive activity increased during the following days until 4 and 5 November 2010, when a series of large explosions sent various PDCs ~15 km away from the summit, killing more than 300 people. According to the Center of Volcanology and Geological Hazard Mitigation at the Merapi Volcano Observatory, this constitutes the largest eruption at this volcano since 1872, with a current Volcanic Explosivity Index estimated between 3 and 4. These hazardous explosive events present a rare opportunity to collect a uniquely detailed dataset of the source, extent, lateral variations and impact of PDC deposits on a densely populated area. The urgency of the application derives from the ephemeral nature of the pristine deposits associated with these events: these will soon be washed away by the current rainy season in Indonesia and it is rare to have the opportunity to collect key data from such hazardous volcanic flows. The main goals of this RAPID are to collect sufficient data, together with an international team, to: 1) document the sources, duration and runout distances of the different PDCs generated during the 2010 eruptive crisis of Merapi; 2) measure the variations in extent, distribution, morphology, lithology and thickness of the different 2010 PDC deposits using different ground-base techniques; 3) obtain and compute a compilation of spatial images taken prior, during and after the eruption. The effects of topography on flow dynamics will be examined in the field through a Real-Time GPS / Laser Rangefinder survey of the surface of the associated deposits immediately after flow emplacement (once these areas are deemed safe).Collection of such a dataset will be used to generate the pre- and post-eruption numerical topographies for testing the sensitivity to geophysical mass flow model (GMFM) outputs for various qualities of digital representations of natural terrain. A high-resolution benchmark DEM dataset will be computed based on the TanDEM misson-X (roughly 3 m spatial resolution, 1-2 m vertical accuracy). Application of TerraSAR data to generate accurate numerical topographies and/or capturing rapid topographic changes associated with the emplacement of PDC deposits over a short period has tremendous potential benefits to better understand the dynamics of such hazardous volcanic flows. Previous authors have shown the importance of the choice of the DEM on computational routines for reconstructing the different paths, velocities and extents of various flows, and for correctly estimating the areas and levels of hazards associated with future volcanic activity. Data obtained during this project will also be integrated into numerical simulations using freely available GMFMs and allow the validity of these models to be tested, with better quantification of best-fit input parameters. This approach will provide one basis for defining hazard zonations of key areas at risk from PDCs at Merapi, which can be directly integrated into the current hazard mitigation plans at this high-risk volcano. Consequently, the work proposed here will be of immediate benefit to all groups involved in assessing volcano hazards either directly (at observatories on some of the most active volcanoes around the world) or through remote sensing techniques. This project will provide direct support to Sylvain Carbonnier (a post-doctoral Fellow at USF through August 2012) and an exceptional research experience for Jose Armando Saballos (PhD student at USF working on debris flow hazards at Concepcion volcano, Nicaragua).