Tsunami intensity mapping: applying the integrated Tsunami Intensity Scale (ITIS2012) on Ishinomaki Bay Coast after the mega-tsunami of Tohoku, March 11, 2011

Abstract

The study applies the Integrated Tsunami Intensity Scale (ITIS 2012) criteria to map the tsunami intensities distribution in the broader Ishinomaki area, for the 9 Mw March 11, 2011 event offshore Tohoku, Japan. Based on reports, satellite imagery and published information, impact data was mapped, intensity values were assigned and thematic impact maps (layers) were created for each of the ITIS 2012 six criteria categories. Most of the criteria result in a mosaic of intensities, which is in many cases due to lack of data, depending on the land use. Two methodologies were used to produce the final map. A land-use-based weighted overlay was applied integrating the six layers, resulting in a final map that rather shows damage tsunami assessment on Ishinomaki area. The second final map was produced using the maximum intensity grade throughout the six layers for each pixel. This map showed an excellent zoning filling in any gaps due to information lack in some layers and areas, with maximum intensity data from the others, highlighting the ITIS 2012 criteria complementarity and is the tsunami intensity map of the study area.