Real-Time Tsunami Forecasting: Challenges and Solutions

Titov, Vasily V.; González, F. I.; Mofjeld, Harold O.; Newman, J. C.

doi:10.1007/1-4020-3607-8_3

Cited by 125 publications

(136 citation statements)

References 16 publications

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“…These studies can be broadly divided into two categories: with a priori assumptions on the fault model (e.g. Satake, 1987Satake, , 1993Hirata et al, 2003;Titov et al, 2005), and without a priori assumptions on the source, namely , Satake et al (2005), Tsushima et al (2009), Wu andHo (2011) and Yasuda and Mase (2012).…”

Section: Inversion Methodologymentioning

confidence: 99%

New study on the 1941 Gloria Fault earthquake and tsunami

Baptista

Miranda

Batlló

et al. 2016

Nat. Hazards Earth Syst. Sci.

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Abstract. The M ∼ 8.3-8.4 25 November 1941 was one of the largest submarine strike-slip earthquakes ever recorded in the Northeast (NE) Atlantic basin. This event occurred along the Eurasia-Nubia plate boundary between the Azores and the Strait of Gibraltar. After the earthquake, the tide stations in the NE Atlantic recorded a small tsunami with maximum amplitudes of 40 cm peak to through in the Azores and Madeira islands. In this study, we present a re-evaluation of the earthquake epicentre location using seismological data not included in previous studies. We invert the tsunami travel times to obtain a preliminary tsunami source location using the backward ray tracing (BRT) technique. We invert the tsunami waveforms to infer the initial sea surface displacement using empirical Green's functions, without prior assumptions about the geometry of the source. The results of the BRT simulation locate the tsunami source quite close to the new epicentre. This fact suggests that the co-seismic deformation of the earthquake induced the tsunami. The waveform inversion of tsunami data favours the conclusion that the earthquake ruptured an approximately 160 km segment of the plate boundary, in the eastern section of the Gloria Fault between −20.249 and −18.630 • E. The results presented here contribute to the evaluation of tsunami hazard in the Northeast Atlantic basin.

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Section: Inversion Methodologymentioning

confidence: 99%

New study on the 1941 Gloria Fault earthquake and tsunami

Baptista

Miranda

Batlló

et al. 2016

Nat. Hazards Earth Syst. Sci.

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“…The use of unit sources have become increasingly popular for PTHA (Geist and Parsons, 2006;Burbidge et al, 2009;Power et al, 2012) and tsunami early warning systems (Titov et al, 2005;Greenslade et al, 2011) due to their computational efficiency at calculating the tsunami hazard for a large number of sites over a large area. The fundamental assumption in using a unit source approach is that tsunami waves behave linearly in deep to moderate water depths .…”

Section: Unit Source Methodsmentioning

confidence: 99%

A probabilistic tsunami hazard assessment for Indonesia

Horspool

Pranantyo

Griffin

et al. 2014

Nat. Hazards Earth Syst. Sci.

179

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Abstract. Probabilistic hazard assessments are a fundamental tool for assessing the threats posed by hazards to communities and are important for underpinning evidence-based decision-making regarding risk mitigation activities. Indonesia has been the focus of intense tsunami risk mitigation efforts following the 2004 Indian Ocean tsunami, but this has been largely concentrated on the Sunda Arc with little attention to other tsunami prone areas of the country such as eastern Indonesia. We present the first nationally consistent probabilistic tsunami hazard assessment (PTHA) for Indonesia. This assessment produces time-independent forecasts of tsunami hazards at the coast using data from tsunami generated by local, regional and distant earthquake sources. The methodology is based on the established monte carlo approach to probabilistic seismic hazard assessment (PSHA) and has been adapted to tsunami. We account for sources of epistemic and aleatory uncertainty in the analysis through the use of logic trees and sampling probability density functions. For short return periods (100 years) the highest tsunami hazard is the west coast of Sumatra, south coast of Java and the north coast of Papua. For longer return periods (500-2500 years), the tsunami hazard is highest along the Sunda Arc, reflecting the larger maximum magnitudes. The annual probability of experiencing a tsunami with a height of > 0.5 m at the coast is greater than 10 % for Sumatra, Java, the Sunda islands (Bali, Lombok, Flores, Sumba) and north Papua. The annual probability of experiencing a tsunami with a height of > 3.0 m, which would cause significant inundation and fatalities, is 1-10 % in Sumatra, Java, Bali, Lombok and north Papua, and 0.1-1 % for north Sulawesi, Seram and Flores. The results of this national-scale hazard assessment provide evidence for disaster managers to prioritise regions for risk mitigation activities and/or more detailed hazard or risk assessment.

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“…The Earth science community often relies on numerical models to better understand tsunami physics (e.g., Titov and Synolakis 1998;Tanioka and Satake 1996;Kowalik 2003), perform hazard assessments (e.g., Geist and Parsons 2006;Borrero et al 2006;González et al 2009), and plan for early warning (e.g., Titov et al 2005;Melgar and Bock 2013;Behrens et al 2010). …”

Section: Introductionmentioning

confidence: 99%

Should tsunami simulations include a nonzero initial horizontal velocity?

Lotto

Nava

Dunham

2017

Earth Planets Space

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Tsunami propagation in the open ocean is most commonly modeled by solving the shallow water wave equations. These equations require initial conditions on sea surface height and depth-averaged horizontal particle velocity or, equivalently, horizontal momentum. While most modelers assume that initial velocity is zero, Y.T. Song and collaborators have argued for nonzero initial velocity, claiming that horizontal displacement of a sloping seafloor imparts significant horizontal momentum to the ocean. They show examples in which this effect increases the resulting tsunami height by a factor of two or more relative to models in which initial velocity is zero. We test this claim with a "full-physics" integrated dynamic rupture and tsunami model that couples the elastic response of the Earth to the linearized acoustic-gravitational response of a compressible ocean with gravity; the model self-consistently accounts for seismic waves in the solid Earth, acoustic waves in the ocean, and tsunamis (with dispersion at short wavelengths). Full-physics simulations of subduction zone megathrust ruptures and tsunamis in geometries with a sloping seafloor confirm that substantial horizontal momentum is imparted to the ocean. However, almost all of that initial momentum is carried away by ocean acoustic waves, with negligible momentum imparted to the tsunami. We also compare tsunami propagation in each simulation to that predicted by an equivalent shallow water wave simulation with varying assumptions regarding initial velocity. We find that the initial horizontal velocity conditions proposed by Song and collaborators consistently overestimate the tsunami amplitude and predict an inconsistent wave profile. Finally, we determine tsunami initial conditions that are rigorously consistent with our full-physics simulations by isolating the tsunami waves from ocean acoustic and seismic waves at some final time, and backpropagating the tsunami waves to their initial state by solving the adjoint problem. The resulting initial conditions have negligible horizontal velocity.

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Real-Time Tsunami Forecasting: Challenges and Solutions

Cited by 125 publications

References 16 publications

New study on the 1941 Gloria Fault earthquake and tsunami

New study on the 1941 Gloria Fault earthquake and tsunami

A probabilistic tsunami hazard assessment for Indonesia

Should tsunami simulations include a nonzero initial horizontal velocity?

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