Scalable multicase urban earthquake simulation method for stochastic earthquake disaster estimation

High-resolution urban earthquake simulations are expected to be useful for improving the reliability of the estimates of damage due to future earthquakes. However, current high-resolution simulation models involve uncertainties in their inputs. An alternative is to apply stochastic analyses using multicase simulations with varying inputs. In this study, we develop a method for simulating the responses of ground and buildings to many earthquakes. By a suitable mapping of computations among computation cores, the developed program attains 97.4% size-up scalability using 320,000 processes (40,000 nodes) on the K computer. This enables the computation of more than 1,000 earthquake scenarios for 0.25 million structures in central Tokyo.