Search for Evidence of the 29 September 2009 Tsunami in Altimeter Data

We have searched in Jason-1 and Jason-2 (OSTM) altimeter passes through the Pacific that occurred approximately 4 to 10 hours after the Samoan earthquake. Two ascending passes of each satellite intersected estimated wavefront positions both southwest of New Zealand and northeast of Hawaii. We have constructed local mean sea surfaces from data before and after the affected passes to difference from them in order to remove short-term oceanographic signals as well as the long-term mean sea surface. We find likely evidence of the tsunami in the southern area but little or none in the northern area. The arrangement of the passes in the southern ocean makes it possible to see snapshots of the wavefront and the propagation over short time (e.g., 112 min) intervals. The amplitude of the tsunami appears to be related to bathymetry.