Pacific Ocean Disasters - Enhanced Detection and Monitoring of Pumice Rafts Using NASA EOS

Pumice rafts are an occasional byproduct of explosive volcanic eruptions that occur near bodies of water. Though these rafts may be infrequent, their substantial size, typically tens of kilometers across, means they pose a serious hazard to shipping interests by blocking the seawater intake valves for ships' engine cooling systems. The focus of this research is on the pumice raft events associated with Tonga 2006, Yemen 2007, and Chile-Argentina border 2011 eruptions. False-color composite images were created with remotely sensed data from the Landsat 5 TM, Landsat 7 ETM+, and MODIS instruments to facilitate visual identification of pumice rafts in high resolution imagery. Additionally, a Material-Of-Interest subpixel classification was implemented to automatically demarcate the extent of the pumice rafts. MODIS was found to be the most useful sensor for tracking larger rafts in the open ocean, while Landsat 5 TM, Landsat 7 ETM+, and ALI were more effective in tracking smaller rafts in lakes and rivers. The pumice rafts generally took on a temperature between that of the ambient air and water temperatures, and this is theorized to be potentially related to characteristics unique to each raft like thickness. That data collected for this study has been compiled to provide an effective tool for further investigation of pumice rafts.