MEASUREMENT OF POST-ERUPTIVE VOLCANIC DEFORMATION AND DEPOSITIONAL FEATURES USING HIGH-RESOLUTION REMOTE SENSING DATA

Lahars, mudflows, mobilized volcanic flows, and tsunamis present an extreme hazard to human activities in coastal areas with active volcanism. We present a system to examine changes in volcanic morphology using a multi-sensor approach to produce high-resolution digital elevation models (DEMs), and measure post-eruption volcanic deformation and depositional features that result from these hazardous phenomena. This system exploits available data sets that have not been previously subjected to systematic or fully coordinated use. In so doing, it employs resources in a manner that is routine in method, but of sufficient quality and availability to answer many important geologic questions.

The multi-sensor approach involves a mix of stereoscopic optical, interferometric radar, and thermal space borne images to generate high-resolution DEMs and multi-sensor analyses of sediment deposits from volcanic activity.

The time and elevation information of DEMs in volcanic areas that are subject to rapid topographic changes enable us to perform topographical correction of interferograms derived from interferometric synthetic aperture radar (InSAR) imaging. It also allows us to determine quantitative volume estimates of dynamically emplaced deposits from lahars, tsunamis, and mud flows, and it provides information for emergency planners to use in risk assessments facing communities in volcanically active areas.

A principal test scenario for our method is the 2009 eruption of Redoubt Volcano in Alaska. A quantitative estimate of lahars created by the volcano’s eruption and carried down the Drift River Valley has important implications for coastal areas, facilities, and populations that face volcanic geohazards.

We demonstrate that the selected remote sensing data sets, if applied in full coordination, are able to produce valuable information pertaining to catastrophic coastal events of vital interest to coastal population centers.