Abstract
We studied ocean-wide propagation properties of four recent trans-Pacific tsunamis based on deep-ocean measurements across the Pacific Ocean. First, we analysed and simulated the 2015 September 16 tsunami generated by the Illapel (Chile) earthquake (Mw 8.4) and compared its ocean-wide propagation with those of three other events: the 2014 Iquique (Mw 8.2), 2010 Maule (Mw 8.8) and 2011 Tohoku (Mw 9.0). The Illapel and Maule tsunami sources are located close to each other and we reconstructed the source spectrum of the larger (i.e.Maule) tsunami by applying spectral deconvolution using the smaller (i.e. Illapel) tsunami as the empirical Green's function. The initial negative phase was found for all four events with durations of 8-29 (Iquique), 20-35 (Illapel), 22-70 (Maule) and 40-79 (Tohoku) min, with the maximum amplitudes of 0.11-0.26, 0.4-0.7, 0.5-2.9 and 1.9-2.5 cm, and the amplitude ratios to the first elevation phases of 20-40 per cent, 22-41 per cent, 29-61 per cent and 12-67 per cent, respectively. Unlike other studies, our results revealed that the duration (Dini) and amplitude (Aini) of the initial negative phase are directly proportional to the earthquake magnitude (Mw)with equations: Mw = 6.129 + 1.629 log(Dini) and Mw = 8.676 + 0.706 log(Aini). No relationships were observed between these parameters (i.e. Dini and Aini ) and distance from the source. The amplitudes of far-field DART waves do not vary with distance or strike angle, and depend only on the Mw. The average far-field deep-ocean amplitudes (Atsu) for the Iquique, Illapel, Maule and Tohoku tsunamis were 0.9, 1.7, 6.0 and 15.0 cm, respectively, yielding the equation: Mw = 8.245 + 0.665 log(Atsu).
| Original language | English |
|---|---|
| Pages (from-to) | 22-36 |
| Number of pages | 15 |
| Journal | Geophysical Journal International |
| Volume | 215 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Oct 2018 |
Bibliographical note
Funding Information:The DART tsunami records were provided by the U.S. National Oceanic and Atmospheric Administration (NOAA) (https://nctr.p mel.noaa.gov/Dart/). We thank the NOAA team for the maintaining and preparing the DART data, which play the major role in advancing our understanding of the deep-ocean and ocean-wide propagation of tsunamis. Most figures were drafted using the GMT software (Wessel & Smith 1998). This article benefited from constructive comments of two anonymous reviewers. MH was funded by the Brunel University London through the Brunel Research Initiative and Enterprise Fund 2017/18 (BUL BRIEF). ABR was partly supported by the RSF Grant 14-50-00095 and the IORAS Project 0149-2015-0039
Publisher Copyright:
© The Author(s) 2018.
Funding
The DART tsunami records were provided by the U.S. National Oceanic and Atmospheric Administration (NOAA) (https://nctr.p mel.noaa.gov/Dart/). We thank the NOAA team for the maintaining and preparing the DART data, which play the major role in advancing our understanding of the deep-ocean and ocean-wide propagation of tsunamis. Most figures were drafted using the GMT software (Wessel & Smith 1998). This article benefited from constructive comments of two anonymous reviewers. MH was funded by the Brunel University London through the Brunel Research Initiative and Enterprise Fund 2017/18 (BUL BRIEF). ABR was partly supported by the RSF Grant 14-50-00095 and the IORAS Project 0149-2015-0039
Keywords
- Pacific Ocean
- Subduction zone processes
- Time-series analysis
- Tsunami warning
- Tsunamis
- Wavelet transform
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology