Tsunami records due to the 2010 Chile Earthquake observed by GPS buoys established along the Pacific coast of Japan

Abstract

A GPS buoy operating about 10 km west of Cape Muroto, southwest Japan, recorded the tsunami due to the 2010 Central Chile Earthquake (Mw 8.8) that occurred on 27 February, 2010. The tsunami due to the Chile Earthquake arrived at the GPS buoy almost one day after the earthquake. The first peak of the tsunami was about 12 cm above the mean sea level. The second peak arrived about one hour and 46 minutes later and was about 20 cm higher than the mean sea level, which was the highest peak among the series of the tsunami waves. The later phases of recognizable tsunami waves continued for about one day after the first arrival of the tsunami. Comparison of these tsunami records with numerically-predicted tsunami suggests that the observed tsunami arrived about 30 minutes later than the arrival time predicted by the numerical simulation. If we manually shift the record on the time series, we find that a longer term of about 1 hour period components fit very well whereas a shorter term of 10–30 minutes of tsunami components shows significant phase shifts. This difference of phase shifts might be due to the effect of dispersion of the tsunami wave.