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The article discusses the development of doomsday machines to simulate natural disasters such as earthquakes, tornadoes and hurricanes. Topics discussed include the U.S. National Science Foundation's (NSF) funding of the Network for Earthquake Engineering Simulation, studies on how buildings respond to earthquakes, and scientists' integration of physical testing with computer models to test massive structures.

After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth's crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel The spontaneous evolution of strength, acceleration, and velodty indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, ve[odty, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake's rupture front quickens dynamic weakening by intense wear of the fault zone. [ABSTRACT FROM AUTHOR]

Presents research on ground motion amplification by sediment to predict seismic loadings for earthquake engineering. Observations of weak motion amplifications at sediment sites; Explanation of observations; Use of earthquake simulations with empirical impulse responses and elastic finite-difference calculations with weakly heterogeneous, random three-dimensional crustal velocity variations show that linear wave propagation can explain observed sediment responses; Other information.

Presents a three-dimensional simulation of a magnitude 7.75 earthquake on the San Andreas Fault in Los Angeles, California. Three-dimensional finite-difference method on a parallel supercomputer; Estimation of the seismic hazard along the San Andreas Fault; Simulation of a rupture on a fault plane; Numerical model for the earthquake rupture and 3D wave propagation.

The article discusses a report within the issue by J. C. Chang and team on a laboratory earthquake simulation experiment using a spinning flywheel on a frictional testing machine to produce an earthquake-like slip event. The rate of acceleration of the wheel was changed to generate kinetic energy to simulated fault zones. Topics include frictional behavior of slip weakening, the effect of friction velocity on fault mechanics, and the behavior of fault zone gouge particles and powder lubrication in earthquake simulations.