MODELING LAHAR INUNDATION WITH THE AID OF SEISMIC DATA AT REDOUBT VOLCANO, COOK INLET, ALASKA

Redoubt Volcano is a 3108m tall stratocone located in Cook Inlet, Alaska that explosively erupts roughly every 20 years. The five eruptions since 1900 all share the common characteristic of being accompanied by multiple large to very large lahars, as well as many that are smaller in magnitude. About 35 km from the crater of Redoubt Volcano lies the Drift River Marine Terminal, that if inundated, has the potential to cause a spill comparable to the Exxon Valdez spill of 1989. These non-Newtonian flows evolve as they move downstream as a result of their bulking and debulking processes. The aim of this project is to model the three largest lahars from the most recent 2009 eruption of Redoubt to predict their area of inundation for future eruptions. Using GIS and lahar simulation programs, inundation models were created and cross-correlated with the known mapped area of inundation done by USGS post-eruption for the three largest 2009 lahars. The input data for these simulations were the USGS 1990 ten-meter interval DEM and estimates of glacial meltwater volume as a measure of initial lahar volume performed by Waythomas (2013). The seismic data associated with the large lahars was also investigated in order to determine the relationship between the precursory seismic data and the magnitude of the lahars that followed, also aiding the accuracy of inundation prediction. To capture the specific characteristics of the Redoubt Volcano lahars, retrospective manipulation of the calibration factors using the known areas of inundation was performed. These modeling techniques can be used for future eruptions of Redoubt in order to aid in the prediction of the lahar inundation.