Walk the inundation limit: A suggestion for future post-tsunami surveys

With any handheld GPS unit and a modest investment of time, typically about one hour per kilometer, it is possible to walk along the debris line and so map the inundation limit of a tsunami. These measurements are not adequate to define runup, but with an accuracy of three meters or better (one meter with simple processing) they are quite adequate for all scientific uses of inundation. The same data are invaluable to emergency managers planning recovery efforts. This short note uses the examples of Amanave and Tula in American Samoa, both affected by the 2009 South Pacific tsunami, to encourage the routine collection of such data in future post-tsunami surveys.