Parallel Earthquake Simulation

Journal of Civil Engineering and Management, 2014

Parallel computing briskly diminishes computation time through simultaneous use of multiple computing resources. In this research, parallel computing techniques have been developed to parallelize a program for obtaining a response of single degree of freedom (SDOF) structure under earthquake loading. The study uses Distributed Memory Processors (DMP) hardware architecture and Message Passing Interface (MPI) compilers directives to parallelize the program. The program is made parallel by domain decomposition. Concurrency in the program is created by dividing the program into two parts to run on different computers, calculating forced response and free response of the first half and the second half. Parallel framework successfully creates concurrency and finds structural responses in significant lesser time than sequential programs.

Journal of Physics: Conference Series, 2009

Earthquakes occurring around the world are responsible for extensive loss of life and infrastructure damage. On average, 1100 earthquakes with significant damage potential occur world-wide per year, and a major societal challenge is to design a human environment that contains appropriate earthquake resistance. Design of critical infrastructure such as large buildings, bridges, industrial facilities and nuclear power plants in seismically active regions is a significant scientific and engineering challenge that encompasses the multiple disciplines of geophysics, geotechnical and structural engineering. Because of the great complexities in earthquake physical processes, traditional approaches to seismic hazard assessment have relied heavily on historical earthquake observations. In this approach, observational data from many locations is homogenized into an empirical assessment of earthquake hazard at any specific site of interest. With major advancements in high performance computing platforms and algorithms, it is now possible to utilize physics-based predictive models to gain enhanced insight about site-specific earthquake ground motions and infrastructure response. This paper discusses recent advancements in geophysics and infrastructure simulations and future challenges in implementing advanced simulations for both earthquake hazard (future ground motions) and earthquake risk (infrastructure response and damage) assessments.

GeoCongress 2006, 2006

Parallel computing is gradually becoming a main stream tool in geotechnical simulations. The need for high fidelity and for modeling of fairly large 3-dimensional (3D) spatial configurations is motivating this direction of research. A new program ParCYCLIC for seismic geotechnical applications has been developed. Salient characteristics of the employed parallel sparse solver will be presented. Using this code, simulations of seismically-induced liquefaction, lateral-spreading, and countermeasures will be presented and discussed.

Pure and Applied Geophysics, 2004

The Lattice Solid Model has been used successfully as a virtual laboratory to simulate fracturing of rocks, the dynamics of faults, earthquakes and gouge processes. However, results from those simulations show that in order to make the next step towards more realistic experiments it will be necessary to use models containing a significantly larger number of particles than current models. Thus, those simulations will require a greatly increased amount of computational resources. Whereas the computing power provided by single processors can be expected to increase according to ''Moore's law,'' i.e., to double every 18-24 months, parallel computers can provide significantly larger computing power today. In order to make this computing power available for the simulation of the microphysics of earthquakes, a parallel version of the Lattice Solid Model has been implemented. Benchmarks using large models with several millions of particles have shown that the parallel implementation of the Lattice Solid Model can achieve a high parallel-efficiency of about 80% for large numbers of processors on different computer architectures.

2016

Integrated earthquake simulation (IES) is a seamless simulation of analyzing the seismic wave propagation process and the structural seismic response process. A model of high fidelity is constructed for an urban area; a three-dimensional model of underground structures is used for the seismic wave propagation process, and a non-linear model is constructed for each building or structure which is located in a target area. Large-scale numerical computation is inevitable for these models of IES; for instance, the underground structure model has more than 100,000,000,000 degree-of-freedoms and the number of the structures is of the order of 100,000. High performance computing is thus employed. Demonstrative examples of IES which are obtained by using K computer, the world 4th fastest supercomputer, are presented. The target is Tokyo which is threatened by a next Tokyo Metropolis Earthquake. Explained are two simulations of analyzing the ground motion amplification process that accounts f...

Journal of Seismology, 2008

This paper presents the current state of integrated simulation for earthquake hazard and disaster. This simulation takes advantage of the macro-micro analysis method; this method estimates an earthquake's strong motion with high spatial and temporal resolution, using the bounding medium theory to obtain optimistic and pessimistic estimates of expected strong motion distribution and the singular perturbation expansion that results in an efficient multi-scale analysis. Integrated earthquake simulation calculates seismic responses for all structures in a target area, inputting simulated strong ground motion to a structure analysis method that is plugged into the system by means of a wrapper; a suitable method, linear or nonlinear, is chosen depending on the type of the structure. The results of all simulations are visualized so that residences and government officials can share a common recognition of earthquake hazard and disaster. Two examples of this integrated earthquake simulations are presented; one is made by plugging nonlinear structure analysis methods into the system, and the other is made for an actual city, the computer model of which is constructed with the help of available geographical information systems.

Pure and Applied Geophysics, 2004

Pure and Applied Geophysics, 2004

Parallel Computing, 2005

The development of high-performance computing facilities such as the Earth Simulator supercomputer and the deployment of dense networks of strong ground motion instruments in Japan (K-NET and KiK-net) have made it possible to directly visualize regional seismic wave propagation during large earthquakes. Our group has developed an efficient parallel finite difference method (FDM) code for modeling the seismic wavefield and three-dimensional visualization techniques, both of which are suitable for implementation on the Earth Simulator. We will show examples of current state of the large-scale FDM simulations of seismic wave propagation by using the Earth Simulator to recast strong ground motions during damaging earthquakes in Tokyo such as the 2000 Tottori-ken Seibu (M J 7.3) earthquake, the 1923 great Kanto earthquake (M7.9), and the 1855 Ansei Edo (M7) earthquake. Significant speedup is achieved using 64-1406 processors of the Earth Simulator with good vector performance of over 40-60% of the theoretical peak speed.

2006

Advances in computer technology and sciences enable us to carry out large-scale numerical simulations. As one of such, the authors have been simulating the entire process of an earthquake, i.e., generation and propagation of an earthquake, responses of structures and damage, and actions by people and communities for earthquake damage. This is an integrated earthquake simulation (IES). With the aid of the latest geographical information system (GIS), IES can automatically construct a computer model of a city of some hundred meters in scale. This paper presents the current state of IES, focusing on the simulation of strong ground motions and structure responses ; the structure response simulation applies several numerical analysis methods. Data exchanges between each method and IES are controlled by an interpreter program. The usefulness of IES is discussed. It is pointed out that IES provides vital information to form a common recognition of possible earthquake hazards and disasters by government o$cials and residents.