JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

H (Human Geosciences) » H-DS Disaster geosciences

[H-DS12] [EE] Tsunami disaster mitigation

Thu. May 25, 2017 10:45 AM - 12:15 PM 105 (International Conference Hall 1F)

convener:Hiroaki Tsushima(Meteorological Research Institute, Japan Meteorological Agency), Toshitaka Baba(Graduate School of Science and Technology, Tokushima University), Eddie N. Bernard(Survival Capsule, LLC), Chairperson:Hiroaki Tsushima(Meteorological Research Institute, Japan Meteorological Agency), Chairperson:Vasily Titov(NOAA/Pacific Marine Environmental Laboratory)

11:15 AM - 11:30 AM

[HDS12-09] Frontal Pop-up Structures and Tsunami Earthquakes

Nugroho Dwi Hananto1, *Satish Chandra Singh2, Yanfang Qin2, Bertand Beunaiche4, Praditya Avianto1, Frederique Leclerc5, Helene Delphine Carton2, Li Linlin3, Paul Tapponnier3 (1.Indonesian Institute of Sciences, Indonesia, 2.Institut de Physique du Globe de Paris, France, 3.Earth Observatory of Singapore, Nanyang Technological University, Singapore, 4.ENSTA Bretagne, France, 5.University of Nice Sophia Antipolis, France)

Keywords:tsunami earthquake, surface rupture, pop-up structures

Tsunami earthquakes are special class of rare earthquakes that produce exceptionally large tsunamis from relatively small earthquakes (e.g., Kanamori, 1972; Polet and Kanamori, 2000; Okal, 1988; Lay and Bileck, 2007). These earthquakes are suggested to propagate up to the subduction front with low rupture velocities and stress drops, but it is not possible to produce large tsunamis from a slip on shallow dipping megathrust. Using recently acquired high-resolution seismic reflection, bathymetry and reflectivity data here we report the presence pop-up structures, bounded by steeply dipping thrusts, near the subduction front and fresh traces of seafloor ruptures in the 2010 Mentawai tsunami earthquake rupture zone (Hill et al., 2012; Singh et al., 2011; Lay et al, 2011; Newman et al., 2011; Bilek et al., 2011), indicating that the rupture reached to the seafloor. Using tsunami modelling study, we show that the co-seismic slip on these steeply dipping conjugate thrusts can uplift the water-column, produce a large localised tsunami, and can explain the observed tsunami on the neighbouring islands. These results suggest that the pop-up structures at the subduction front might be the main cause of tsunami during tsunamigenic earthquakes, and can be used for tsunami mitigation study.