Tsunami inundation mapping: Comparing inundation limits interpreted from satellite imagery to field observations in American Samoa and Sumatra

Tsunami inundation limits are one of many parameters used to assess both the immediate impact of and potential risk from future tsunamis. If identified quickly, inundation information can be used to direct relief, aid, and research efforts to the most heavily impacted areas. Following the immediate response, tsunami inundation limits are used to verify tsunami models, improve plans for rebuilding, prepare evacuation routes, and can be compared with other impacted locations either locally or from previous tsunami events world-wide. Ultimately accurate and detailed tsunami inundation information will help governments and citizens reduce the loss of life and property caused by tsunamis in coastal areas world-wide. Tsunami inundation limits are determined by interpreting wave disturbed areas in satellite imagery or through direct field mapping. Both methods have advantages and disadvantages. Image interpretation is limited by the availability, quality, and resolution of satellite images but the results cover a large area and can be produced relatively quickly without traveling to the impacted area. Inundation limits mapped in the field are more detailed, accurate, and reliable than image interpretations but can be difficult or impossible to collect in remote areas, typically cover a small area, and the results take more time and effort to produce. This study compares tsunami inundation limits produced by the two methods described above for locations in American Samoa impacted by the September 29, 2009 tsunami and locations in Sumatra impacted by the December 26, 2004 tsunami. Preliminary results suggest that satellite image interpretations may in some cases underestimate the limit of tsunami inundation. The two methods will be evaluated to provide guidance for inundation mapping of tsunamis.