S U M M A R Y W phase is a long period phase arriving before S wave. It can be interpreted as superposition of the fundamental, first, second and third overtones of spheroidal modes or Rayleigh waves and has a group velocity from 4.5 to 9 km s−1 over a period range of 100–1000 s. The amplitude of long period waves better represents the tsunami potential of an earthquake. Because of the fast gro...

Recently, concerning failure of structures due to earthquakes, special investigations of near fault ground motions have been noticed. Hence, in this paper, characteristics of near field ground motions have been considered in horizontal and vertical directions. In this consideration, the record averages have been compared with Uniform Building Code and Eurocode8 spectra in two levels. In additio...

Besides generating seismic waves, which eventually dissipate, an earthquake also generates a static displacement field everywhere within the Earth. This global displacement field rearranges the Earth’s mass thereby causing the Earth’s rotation and gravitational field to change. The size of this change depends upon the magnitude, focal mechanism, and location of the earthquake. The Sumatran eart...

Earthquake-induced increases in streamflow, producing ;0.7 km3 of total excess water, were documented after the 1999 (Mw 5 7.5) Chi-Chi earthquake in central Taiwan. Analysis of stream gauge data and well records suggests that the excess water originated in the mountains. We propose that the extensive high-angle fractures formed during the earthquake allow rapid release of water from mountains ...

A recently developed nonstationary stochastic model of strong earthquake ground motion is described. The model employs filtering of a white-noise process, where nonstationarity is achieved by modulating the intensity and varying the filter parameters in time. The model is fitted to a target accelerogram by matching a set of statistical measures that characterize the evolution of the intensity, ...

We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of ...

In this research, optimal design and assessment of multiple tuned mass dampers (MTMDs) capability in mitigating the damage of nonlinear steel structures subjected to earthquake excitation has been studied. Optimal parameters of TMDs on nonlinear multi-degree-of-freedom (MDOF) structures have been determined based on minimizing the maximum relative displacement (drift) of structure where for sol...

Since 1 December 1987, a very broadband seismographic system has been in operation at the Kresge Laboratory of the California Institute of Technology. This system consists of the Streckeisen-1 very broadband sensor (Wielandt and Streckeisen, 1982), the Kinemetrics FBA-23 triaxial force balance accelerometer and a Quanterra data-logger with a 24-bit (for Streckeisen-1) and a 16-bit (for FBA-23) ...