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Dispersive tsunami of the 2010 Chile earthquake recorded by the high‐sampling‐rate ocean‐bottom pressure gauges
Author(s) -
Saito Tatsuhiko,
Matsuzawa Takanori,
Obara Kazushige,
Baba Toshitaka
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045290
Subject(s) - geology , seismology , submarine pipeline , tide gauge , tsunami earthquake , tsunami wave , waveform , range (aeronautics) , dispersion (optics) , oceanography , sea level , radar , computer science , telecommunications , materials science , physics , optics , composite material
Cabled ocean‐bottom pressure gauges deployed offshore Japan recorded the pressure change associated with the 2010 Chile earthquake tsunami over a wider frequency range than that of coastal tide gauges or hydrophones. Although it was difficult to recognize the dispersive features in the original records, the spectrograms clearly showed wave dispersion. A low‐frequency tsunami (∼1 mHz) arrived after an elapsed time of 24 hr from the earthquake origin time, while a high‐frequency tsunami (∼9 mHz) arrived after an elapsed time of 48 hr. The arrival times can be explained by assuming a constant water depth of 4 km. However, the calculated waveform does not correctly reproduce the number of wave packets appearing in the observations. Cabled ocean‐bottom pressure gauges deployed offshore can record broadband tsunami signals reflecting the wide‐wavenumber‐range spatial spectrum for sea‐bottom deformation caused by the earthquake.