in practice, foundations are settled on the soft layers of soil, so the ground must be designed as well as the structure. wave propagation and hysteresis damping of soil layers may alter the seismic response of flexible-base design in comparison to controversial fixed-base. lots of uncertainties about this issue, necessitate most of seismic design standards including iranian standard no. 2800 t...

High-resolution 3-D P and S wave crustal velocity and Poisson’s ratio models of the 1992 Landers earthquake (Mw 7.3) area are determined iteratively by a wave-equationbased travel-time seismic tomography (WETST) technique. The details of data selection, synthetic arrival-time determination, and trade-off analysis of damping and smoothing parameters are presented to show the performance of this ...

[1] Earth’s background vibrations at frequencies below about 0.5 Hz have been attributed to ocean-wave energy coupling into the ground and propagating as surface waves and P-waves (compressional waves deep within the Earth). However, the origin and nature of seismic noise on land at frequencies around 1 Hz has not yet been well studied. Using array beamforming, we analyze the seismic noise fiel...

This article describes a parallel implementation of a ray tracing algorithm in a heterogeneous anisotropic geological medium. The shortest path method, which was used for calculations, can give ray path and travel time of seismic wave propagation even for a random and discontinuous velocity field. The high precision required in such calculations was obtained by employing a dense computational g...

Seismic waves propagate through the earth as a superposition of different wave modes. Seismic imaging in areas characterized by complex geology requires techniques based on accurate reconstruction of the seismic wavefields. A crucial component of the methods in this category, collectively known as wave-equation migration, is the imaging condition that extracts information about the discontinuit...

seismic piezocone device (scptu) together with resonant column and cyclic triaxial test apparatus are employed to measure small strain shear modulus (g0) of carbonate sandy and clayey soils of southern coasts of iran. a large area of southern regions of iran is formed from clay, silt and sand. in this study, maximum shear modulus that is derived from both field (by seismic piezocone) and labora...

6 Recent studies attribute land double-frequency (DF) microseism observations to deep7 water generation. Here we show that near-coastal generation is generally the dominant 8 source region. This determination is based on observations at land and ocean seismic 9 stations, buoys, gravity wave hindcasts, and on beamforming results from continental 10 seismic arrays. Interactions between opposing o...

Wave-equation, finite-frequency imaging and inversion still face many challenges in addressing the inversion of highly complex velocity models as well as in dealing with nonlinear imaging e.g., migration of multiples, amplitude-preserving migration . Extended images EIs are particularly important for designing image-domain objective functions aimed at addressing standing issues in seismic imagi...

In [1] we present a method of signal restoration to improve the signal to noise ratio, sharpen seismic arrival onset, and act as an empirical source deconvolution of specific seismic arrivals. The method is used on the shear wave time window containing SKS and S, whereby using a Gaussian PSF produces more impulsive, narrower, signals in the wave train. The resulting restored time series facilit...