July 2021

ChEESE partners Arnau Folch (BSC), Jorge Macias (UMA) and Josep de la Puente (BSC) presented a module on Urgent Computing for Natural Disasters at the EU ASEAN High Performance Computing (HPC) Virtual School: System Design & HPC Applications on 9 July 2021. 

Arnau Folch presented an overview of the ChEESE project as well as "Operational Forecast of Volcanic Ash Clouds"; Jorge Macias presented "Faster Than Real-Time (FTRT) Tsunami Simulations"; and Josep de la Puente presented "Urgent Computing for Earthquakes".

This virtual school, which took place from 5-9 July 2021, had a hands-on virtual curriculum taught by foremost international experts in HPC technology and its applications to computational sciences. It was hosted by National Science and Technology Development Agency (NSTDA) Supercomputer Center (ThaiSC), Thailand. Students were composed of 60 selected participants from ASEAN Member States. 

This event was carried out within the framework of the Enhanced Regional EU-ASEAN Dialogue Instrument (E-READI). E-READI, a demand-driven instrument that supports ASEAN regional integration by strengthening EU-ASEAN networks and exchanging knowledge and experience in policy areas of joint interest. In addition to engaging with policy makers from EU and ASEAN institutions and Member States, it facilitates ongoing and new dialogues with civil society, the private sector, and other relevant stakeholders across various policy areas. It further strengthens the standing EU-ASEAN Dialogue Meeting on Science and Technology and the EU-ASEAN Strategic Partnership. 

ChEESE had also previously taught ASEAN participants in a training course it organised at the Barcelona Supercomputing Center called “HPC and natural hazards: modelling tsunamis and volcanic plumes using European flagship codes". Learn more here.

3D fully coupled acoustic-elastic simulation of the 2018 Sulawesi earthquake and tsunami in Palu Bay: (a) map view of the vertical sea surface velocity (b) sea surface height of the initiated tsunami (after 60s), (c) 3D view of earthquake and tsunami model, (d) sea surface displacement directly after the earthquake.

ChEESE partners LMU and TUM, in collaboration with researchers from Stanford University, USA, successfully performed the first petascale production runs and scaling studies for the ChEESE pilot demonstrator on physics-based tsunami-earthquake interaction on several supercomputers - SuperMUC-NG, Shaheen, Mahti and Frontera. The respective pilot demonstrator develops a new model to study how tsunamis are generated, starting from the dynamic earthquake rupture process along systems of faults via the generation and propagation of elastic, acoustic and gravitational waves in complex solid earth and ocean models up to the generation and propagation of tsunami waves. LMU and TUM developed a 3D fully coupled elastic-acoustic and gravity wave propagation solver in the earthquake simulation software SeisSol, building upon 2D approaches developed by the Stanford group. In a "landmark" simulation they perform the first fully coupled simulation of an actual earthquake-tsunami event: the 2018 Sulawesi earthquake and subsequent tsunami in the Palu Bay. The respective suprising and devastating tsunami, reaching run-up heights of more than 9m in the Bay, resulted from a strike-slip earthquake, which is producing predominately horizontal displacements of the ocean floor.  Nevertheless, recent simulations using 2D tsunami shallow water modes suggested that the Palu tsunami can be primarily understood from the complex interaction of earthquake rupture and the complex 3D structure of the Bay. Our new fully-coupled elastic-acoustic model further confirms this explanation and establishes a novel method for solving an entirely new class of earthquake-tsunami problems.

Simulations were executed with up to 261 billion degrees of freedom. The largest simulation ran for 5.5 hours on 3,072 nodes of the SuperMUC-NG supercomputer, installed at the Leibniz Supercomputing Centre, achieving a sustained performance of 3.1 PFLOPS.  Further studies to evaluate the parallel scalability of the new SeisSol model were executed on the supercomputers Mahti, Shaheen-II and Frontera. As part of a collaboration with the Texas Advanced Computing Center, scalability was tested on up to 7000 compute nodes, maintaining excellent parallel efficiency. 

The respective work has been accepted and will be presented at the SC21 Supercomputing Conference in November 2021: 

Lukas Krenz, Carsten Uphoff, Thomas Ulrich, Alice-Agnes Gabriel, Lauren S. Abrahams, Eric M. Dunham, Michael Bader: "3D Acoustic-Elastic Coupling with Gravity: The Dynamics of the 2018 Palu, Sulawesi Earthquake and Tsunami". 

Update (22 November 2021): This paper has been published in in open access. Read it here.