The effect of uncertainty in earthquake fault parameters on the maximum wave height from a tsunami propagation model

D Burbidge,C Mueller,W Power

doi:10.5194/nhess-15-2299-2015

D Burbidge, C Mueller + Show 1 more

Open Access

https://doi.org/10.5194/nhess-15-2299-2015

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Abstract

Abstract. Over the last decade precomputed tsunami propagation model databases have been used extensively for both tsunami forecasting and hazard and risk assessment. However, the effect of uncertainty in the earthquake source parameters on the results of the simulated scenarios of tsunami propagation has not always been examined in great detail. Here we have undertaken a systematic study of the uncertainty in the maximum wave height of a tsunami (hmax) as a function of the uncertainty in the rupture parameters of the earthquake that generates it (specifically the strike, dip, rake, depth and magnitude). We have shown that even for the simple case of a tsunami propagating over flat bathymetry, the coefficient of variation (CoV) and skewness of the distribution of hmax was a complex function of the choice of rupture parameter, distance and azimuth. The relationships between these parameters and CoV became even more complex as the bathymetry used became more realistic. This has major potential implications for both how warning centres operate in the future and how the uncertainty in parameters describing the source should be incorporated into future probabilistic tsunami hazard assessments.

Highlights

Since the 2004 Indian Ocean tsunami, there has been a major increase globally in tsunami propagation modelling for use in both tsunami warning and hazard and risk assessment
Previous studies into what affects the tsunami wavefield have mostly focused on various physical parameters such as source effects (Geist, 1999), bathymetry (Geist, 2009), tides (Weisz and Winter, 2005), dispersion of wave propagation (Glimsdal et al, 2013), Coriolis force (Shuto, 1991), effects of friction (Myers and Baptista, 2001) and land cover roughness when propagating onshore (Kaiser et al, 2011)
The bathymetry was flat with a uniform depth

Summary

Introduction

Since the 2004 Indian Ocean tsunami, there has been a major increase globally in tsunami propagation modelling for use in both tsunami warning and hazard and risk assessment. Probabilistic tsunami hazard assessments (PTHAs) have been created for the United States (Geist and Parsons, 2006; González et al, 2009), Australia (Burbidge et al, 2008, 2009), New Zealand (Power et al, 2007; Power, 2013), the Mediterranean (Sørensen et al, 2012; Lorito et al, 2015), the northwest Indian Ocean (Heidarzadeh and Kijko, 2011), Indonesia (Horspool et al, 2014) and the even the entire globe (Løvholt et al, 2014). We present a systematic study of this issue, starting with simple source models in a flat ocean and moving on to three examples which use a more realistic bathymetry. The accuracy of tsunami simulation depends on the consideration of these factors in the numerical implementation, and on the variability and uncertainties associated with them

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