Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Faster-Than-Real-Time Computing of Tsunami Early Warning Systems Jorge Mac´ ıas EDANYA Research Group (Differential Equations, Numerical Analysis and Applications) Universidad de M´ alaga GPU Technology Conference , San Jose, CA, 26-29 March, 2018
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements “Life-Saving Actions” In 2016 UNESCO project “Life-Saving Actions: Disaster preparedness and seismic and tsunami risk reduction in the south coast of the Dominican Republic” Haga click para visualizar la simulaci´ on
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements “Life-Saving Mathematics” 2016 European Researchers’ Night: “Life-Saving Mathematics” Outreach activities for students and the general public Matemáticas que salvan vidas Jorge Macías Sánchez Universidad de Málaga
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements “Life-Saving GPUs” 2018 NVIDIA Global Impact Award: “Life-Saving GPUs” GPU fast computing aiming saving lives Global Impact Award Finalist Using GPUs with Aim to Spare Lives Ahead of Tsunamis March 12, 2018 by TONIE HANSEN The University of Málaga team advances capabilities of tsunami early warning systems.
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Why we do What we do / Why we do it
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Why we do What we do / Why we do it Tsunami Science - Aim: Saving Lives 0 casualties in the farfield Minimize casualties in the nearfield
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Why we do What we do / Why we do it Tsunami Science - Aim: Saving Lives 0 casualties in the farfield Minimize casualties in the nearfield As modelers / Numerical specialists Developing numerical tools to simulate tsunamis Get our numerical models used in TEWS Need to compute extremely fast (if aim is saving lives) This was UNTHINKABLE some years ago
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements What we do: solution to a specific problem Focus Achieving much FTRT predictions in the context of TEWS
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements How we do it Two Ingredients 1. Numerical model: Tsunami-HySEA Robust Efficient Precise Validated 2. GPU and multi-GPU Extremely fast computing (and inexpensive)
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements The result A novel approach How TEWS do work Decision Matrices Precomputed Databases The rules of the game have changed
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Model features Seabed deformation model: Okada Model Okada model for seabed deformation Hypothesis: Intantaneous transmition to the water free surface Then a shallow water model propagates the initial tsunami wave Okada Model (1985) To define the initial seabed deformation is necesary to provide: Longitude, Latitude, and source depth Fault plane length and width Dislocation Strike angle, slip angle and dip angle Tsunami-HySEA model
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Model features Seabed deformation model: Multi-Okada Model Multiple Okada segments can be defined Rupture can be synchronous or asynchronous Seabed deformation model Other rupture models can be implemented Filtering (as Kajiura) - Nosov-Kolesov Support for rectangular or triangular faults Tsunami-HySEA model
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Model features Seabed deformation model: Multi-Okada Model Multiple Okada segments can be defined Rupture can be synchronous or asynchronous Seabed deformation model Other rupture models can be implemented Filtering (as Kajiura) - Nosov-Kolesov Support for rectangular or triangular faults Others capabilities Nested meshes (two-way) 2D domain decomposition and load balancing Direct output of time series NetCDF input/output files Resuming a stored simulation (new grids and new points for the time series) Overlapping writing and computing Tsunami-HySEA model
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Model equations Shallow Water Models frequently used in ocean and coastal simulations seldom used to explicitely reproduce coastal inundation or run-up height. Non Linear Shallow Water Equations 8 ∂ h ∂ t + ∂ q x ∂ x + ∂ q y ∂ y = 0 , > > > > > > > > ✓ q 2 ✓ q x q y > > ∂ q x ∂ t + ∂ ◆ + ∂ ◆ = gh ∂ H h + g > < x 2 h 2 ∂ x − S x , ∂ x ∂ y h > > > > ✓ q x q y > q 2 ! > ∂ q y ∂ t + ∂ ◆ + ∂ = gh ∂ H h + g > y > 2 h 2 ∂ y − S y . > > > ∂ x h ∂ y : ρ density; g gravity; H ( x ) bathymetry; h ( x , t ) , water layer thickness; ( u x ( x , t ) , u y ( x , t )) flow velocity; q x ( x , t ) = u x ( x , t ) h ( x , t ) , q y ( x , t ) = u y ( x , t ) h ( x , t ) fluxes; S f = ( S x , S y ) bottom friction effects. Tsunami-HySEA
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Numerics Numerics: A family of Finite Volume numerical schemes Scenarios : WAF method (LW+HLL) 1 and higher order TEWS : hybrid 2s+WAF 2 Laboratory experiments : higher order methods Wet/Dry front treatment 3 , 4 , 5 Nested meshes and/or AMR (GPU) 1 de la Asunci´ on et al. (2012). Efficient GPU implementation of a two waves TVD-WAF method for the two-dimensional one layer shallow water system on structured meshes, Computers & Fluids. 2 Article in progress 3 Castro, Gonz´ alez-Vida, Par´ es (2005). Numerical treatment of wet/dry fronts in shallow water flows with a modified Roe scheme. Math. Mod. and Meth. in Applied Sci. 4 Gallardo, Par´ es, Castro (2007) . On a well-balanced high-order finite volume scheme for shallow water equations with topography and dry areas. J. Comput. Phys. 5 Castro, Fern´ andez, Ferreiro, Garc´ ıa, Par´ es (2009) . High order extensions of Roe schemes for two dimensional nonconservative hyperbolic systems. J. Sci. Comput. Tsunami-HySEA model
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Numerics Numerics: A family of Finite Volume numerical schemes Scenarios : WAF method (LW+HLL) 1 and higher order TEWS : hybrid 2s+WAF 2 Laboratory experiments : higher order methods Wet/Dry front treatment 3 , 4 , 5 Nested meshes and/or AMR (GPU) Nice properties Well-balanced (avoid spurious oscillations) Transitions from sub to super critical situations (arrival to coast) Positivity (no negative layer thickness) Inundation area and runup heights are model outputs Discontinuities in data or solutions (no need to smooth bathymetry) Implementation CUDA/MPI - GPU/Multi-GPU (very short computing times) Tsunami-HySEA model
Introduction What / How / Why The model Validation The Challenge Tohoku 2011 Concluding Acknowledgements Tsunami-HySEA. Validation A long and exhaustive benchmarking process - NTHMP standards 1. Propagation and Inundation 2. Tsunami currents 3. Landslide generated tsunamis Benchmarks composed of 1. Analytical solutions 2. Laboratory experiments 3. Field data
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