GPS Buoy And Seabed Installed Wave Gauge Application to Offshore Tsunami Observation

Abstract

This paper explained results of the GPS Buoy observed offshore tsunami records caused by the 2001 Peru-Earthquake, the 2003 Tokachi-off Earthquake and the 2004 Tokaido-off Earthquake. Observed GPS buoy tsunami data were compared with seabed installed acoustic and pressure wave gauges nationwide network data and coastal tide stations data. It was concluded that GPS Buoy successfully observed tsunami profiles with good precision at the three events. GPS buoy of 100m deep observed the first tsunami wave 10 minutes earlier than the coastal tide station, which indicated that GPS buoy will be useful for rapid coastal evacuation and tsunami disaster reduction. Tsunami amplification characteristics from offshore GPS buoy observation points to coastal tide gauge points were also clarified at the two ports area, the Ofunato Port and the Murotsu Port, by conducting tsunami profile wave-to-wave analysis and frequency spectrum analysis.