Modelling earthquakes in Thessaloniki

Predicting earthquakes is impossible, but High-Throughput Compute helps to anticipate their effects

Earthquakes are amongst the world’s most destructive natural disasters and the only way to avoid catastrophes is good planning and damage control.

Earthquakes are caused by seismic waves that travel through solid rock causing shakes and tremors as they go along. Every region has its own geological set up that influences how the waves propagate within it. And by studying how seismic waves travel it is possible to predict how a site will respond to an earthquake.

Andreas Skarlatoudis, from the University of Thessaloniki in Greece, studied wave propagation in the Thessaloniki area, as part of his PhD research.

Armed with the region’s geological parameters, Skarlatoudis designed a computational model to see how Thessaloniki looks like underground and how seismic waves propagate beneath the city.

Building an accurate model was not a trivial task: Skarlatoudis had to solve millions of partial differential equations and for that he decided to turn to grid computing. With the resources of the Greek National Grid Initiative, he managed to solve all his equations in about five days. Without the grid, it would have taken months to complete the task.

Later on, Skarlatoudis compared the seismograms he built from the HTC calculations with real data gathered during the 4th July 1978 Thessaloniki earthquake. He discovered that they matched and that his model was correct.

The next step was to map the simulated effects of the earthquake in a chart. This type of map can be used to inform the local authorities and the civil protection services as well as helping them to prepare the regional response and prevent serious infrastructure damages and human tragedies.

The Arch of Galerius in Thessaloniki (Illustration: wiki commons / Mark J. Nelson)

 
References

A.A. Skarlatoudis et al. (2011). Site response study of the city of Thessaloniki (N. Greece), for the 04/07/1978 (M5.1) aftershock, using a 3D Finite-Difference wave propagation method. Bull. Seism. Soc. Am. (abstract)

A.A. Skarlatoudis et al.  (2011). Spatial distribution of site-effects and wave propagation properties in Thessaloniki (N. Greece) using a 3D Finite Difference method,Geoph. J. Int., 185, 485-513. (abstract)