Stochastic analysis and uncertainty assessment of tsunami wave height using a random source parameter model that targets a Tohoku-type earthquake fault

Abstract

We created a fault model with a Tohoku-type earthquake fault zone having a random slip distribution and performed stochastic tsunami hazard analysis using a logic tree. When the stochastic tsunami hazard analysis results and the Tohoku earthquake observation results were compared, the observation results of a GPS wave gauge off the southern Iwate coast indicated a return period equivalent to approximately 1,709 years (0.50 fractile), and the observation results of a GPS wave gauge off the shore of Fukushima Prefecture indicated a return period of 600 years (0.50 fractile). Analysis of the influence of the number of slip distribution patterns on the results of the stochastic tsunami hazard analysis showed that the number of slip distribution patterns considered greatly influenced the results of the hazard analysis for a relatively large wave height. When the 90 % confidence interval and coefficient of variation of tsunami wave height were defined as an index for projecting the uncertainty of tsunami wave height, the 90 % confidence interval was typically high in locations where the wave height of each fractile point was high. At a location offshore of the Boso Peninsula of Chiba Prefecture where the coefficient of variation reached the maximum, it was confirmed that variations in maximum wave height due to differences in slip distribution of the fault zone contributed to the coefficient of variation being large.

Probabilistic Earthquake–Tsunami Multi-Hazard Analysis: Application to the Tohoku Region, Japan

“…The simulation procedure is based on a spectral synthesis method Fukutani et al, 2016), where the earthquake slip distribution is characterized by wavenumber spectra (Mai and Beroza, 2002;Lavallée et al, 2006). Scaling relationships that evaluate the source parameters as a function of moment magnitude are needed for stochastic tsunami simulation (e.g., rupture size and spectral characteristics of the rupture).…”

“…In the first category, PTHA is conducted by using tsunami catalogs (Burroughs and Tebbens, 2005;Tinti et al, 2005;Orfanogiannaki and Papadopoulos, 2007); in the second category, different scenariobased PTHA methods are suggested (Geist and Dmowska, 1999;Downes and Stirling, 2001;Farreras et al, 2007;Liu et al, 2007;Power et al, 2007;Yanagisawa et al, 2007;Burbidge et al, 2008;González et al, 2009;Løvholt et al, 2012). In the third category, a combination of the two previous categories is considered (Geist, 2005;Geist and Parsons, 2006;Annaka et al, 2007;Thio et al, 2007;Burbidge et al, 2008;Parsons and Geist, 2008;Grezio et al, 2010Grezio et al, , 2012Horspool et al, 2014;Fukutani et al, 2016). Specifically, for near-source subduction zones, Fukutani et al (2016) extended the methodology of Annaka et al (2007) for a Tohoku-type (M9) earthquake with fixed rupture geometry.…”

“…In the third category, a combination of the two previous categories is considered (Geist, 2005;Geist and Parsons, 2006;Annaka et al, 2007;Thio et al, 2007;Burbidge et al, 2008;Parsons and Geist, 2008;Grezio et al, 2010Grezio et al, , 2012Horspool et al, 2014;Fukutani et al, 2016). Specifically, for near-source subduction zones, Fukutani et al (2016) extended the methodology of Annaka et al (2007) for a Tohoku-type (M9) earthquake with fixed rupture geometry. They considered several cases for earthquake magnitude, slip pattern, and occurrence probability.…”

Simulation-Based Probabilistic Tsunami Hazard Analysis: Empirical and Robust Hazard Predictions

“…The simulation is based on the probabilistic models of earthquake source parameters ) and the spectral synthesis method (Goda et al 2014;Fukutani et al 2016), characterizing the earthquake slip distribution by wavenumber spectra (Mai and Beroza 2002). Specifically, for each discrete value of magnitude M i (target magnitude hereafter), many samples of the source parameters are necessary to define a slip field on the fault plane comprehensively.…”

“…In the first category, PTHA is conducted using tsunami catalogs (Burroughs and Tebbens 2005;Kulikov et al 2005;Tinti et al 2005;Orfanogiannaki and Papadopoulos 2007), whereas in the second category, different ''scenario-based'' PTHA methods are suggested (Geist and Dmowska 1999;Downes and Stirling 2001;Farreras et al 2007;Liu et al 2007;Power et al 2007;Yanagisawa et al 2007; Burbidge et al 2008;González et al 2009;Løvholt et al 2012). In the third category, a combination of the previous two is considered (Geist 2005;Geist and Parsons 2006;Annaka et al 2007;Thio et al 2007;Burbidge et al 2008;Parsons and Geist 2009;Grezio et al 2010Grezio et al , 2012Horspool et al 2014;Fukutani et al 2016). Recently, De Risi and Goda (2016) have developed a new simulation-based multihazards approach for ground motions and tsunamis.…”