The 2004 Sumatra tsunami in the Southeastern Pacific Ocean: New Global Insight from Observations and Modeling

Abstract

The 2004 Sumatra tsunami was an unprecedented global disaster measured throughout the world oceans. The present study focused on a region of the southeastern Pacific Ocean where the “westward” circumferentially propagating tsunami branch converged with the “eastward” branch, based on data from fortuitously placed Chilean DART 32401 and tide gauges along the coast of South America. By comparison of the tsunami and background spectra, we suppressed the influence of topography and reconstructed coastal “spectral ratios” that were in close agreement with a ratio at DART 32401 and spectral ratios in other oceans. Findings indicate that even remote tsunami records carry spectral source signatures (“birth‐marks”). The 2004 tsunami waves were found to occupy the broad frequency band of 0.25–10 cph with the prominent ratio peak at period of 40 min related to the southern fast‐slip source domain. This rupture “hot‐spot” of ∼350 km was responsible for the global impact of the 2004 tsunami. Data from DART 32401 provided validation of model results: the simulated maximum tsunami wave height of 2.25 cm was a conservative approximation to the measured height of 2.05 cm; the computed tsunami travel time of 25 h 35 min to DART 32401, although 20 min earlier than the actual travel time, provided a favorable result in comparison with 24 h 25 min estimated from classical kinematic theory. The numerical simulations consistently reproduced the wave height changes observed along the coast of South America, including local amplification of tsunami waves at the northern stations of Arica (72 cm) and Callao (67 cm).

Source Estimate for the 1960 Chile Earthquake From Joint Inversion of Geodetic and Transoceanic Tsunami Data

“…The arrival time and waveform discrepancies between the simulated and observed tsunami waves at far field had been noted for the 1960 Chile tsunami as well as more recent transoceanic tsunamis (e.g., Imamura et al, 1987;Rabinovich et al, 2017). In recent years, this phenomenon was well explained by the effects of elasticity of the Earth, water compressibility, gravity change by tsunami motion, and ocean stratification (Allgeyer & Cummins, 2014;Ho et al, 2017;Tsai et al, 2013;Watada, 2013;Watada et al, 2014).…”

The December 2018 Anak Krakatau Volcano Tsunami as Inferred from Post-Tsunami Field Surveys and Spectral Analysis

“…A Hanning window length of 60 min (60 data points) was considered for spectral analysis, thus the overlap was 30 min. The peaks of the spectral plots are considered to be the dominant periods of the tsunami (Rabinovich et al 2008(Rabinovich et al , 2017Heidarzadeh et al 2015b).…”

Re-examination of Slip Distribution of the 2004 Sumatra–Andaman Earthquake (Mw 9.2) by the Inversion of Tsunami Data Using Green’s Functions Corrected for Compressible Seawater Over the Elastic Earth

“…The 2004 Sumatra-Andaman earthquake (3.295°N , 95.982°E, depth = 30.0 km, M = 9.1 at 00:58:53 UTC on 26 December 2004 according to the United States Geological Survey [USGS]) is the largest event to have occurred so far in the twenty-first century, generating a devastating tsunami and causing severe damage and loss of human life (Satake, 2014). The 2004 tsunamis propagated through the Indian Ocean, spread to the Atlantic Ocean and the Pacific Ocean (Titov et al, 2005), and were recorded at numerous tide gauges (TG), ocean bottom pressure gauges (OBPG), and DART [Deep-ocean Assessment and Reporting of Tsunamis] stations (Rabinovich & Thomson, 2007;Rabinovich et al, 2011aRabinovich et al, , 2017. The 2004 earthquake was the first tsunami captured by satellite altimetry (SA) measurements (Gower, 2005;Smith et al, 2005).…”