Volcanic product detection after the 2010 Merapi eruption by using VHR SAR data

The volume estimation of products is critical for volcanic hazard mitigation, especially for lahars (mudflow) occurrences during rainy season at Merapi, and at active volcanoes subject to lahars elsewhere. Lahars can affect inhabited areas around a volcano, even several years after an eruption. In this work, we present an innovative approach to detect and estimate the volume of pyroclastic flow deposits. We exploited data collected from the very high resolution SAR sensor on board of the COSMO-SkyMed satellite constellation. By comparing a pre-eruption airborne Digital Surface Model (DSM) with a new one obtained applying SAR Interferometry technique to COSMO-SkyMed data, we estimate the volume of the pyroclastic material emitted during the 2010 Merapi eruption. Results show pyroclastic flow deposit thicknesses of up to 75 m that fill canyons on flank of volcano, and are observed up to 16 km far from the mountain summit. The total volume of the deposits is around 117×10⁶ m³.