Earth Planets Space, Vol. 63 (No. 6), pp. e5-e8, 2011
Teruyuki Kato1, Yukihiro Terada2, Hitoyoshi Nishimura2, Toshihiko Nagai3, and Shun'ichi Koshimura4
1Earthquake Research Institute, The University of Tokyo
2Kochi National College of Technology
3Port and Airport Research Institute
4Graduate School of Engineering, Tohoku University
(Received February 8, 2011; Revised May 3, 2011; Accepted May 6, 2011; Online published August 15, 2011)
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.
Key words: GPS, RTK, tsunami, GPS buoy, Chile tsunami, numerical simulation.