in this study, analysis is presented in two steps. in the first step, the theoretical s-wave displacement spectra, conditioned by frequency-independent q, was fitted with the observed displacement spectra. therefore corner frequency, moment magnitude and frequency-independent q for each record were estimated simultaneously and the estimate of error is given in the root-mean-square sense over al...

based on the standards for design of structures, any structure should be designated for seismic loads and any combinations containing seismic loads. for spectral analysis of a structure, the site effect is taken into account by considering its effects on the design spectra. because of different lateral and vertical stiffness of the soil layers underneath the structure, the design spectra are di...

in this paper, a new algorithm for studying elastic wave propagation in the phononic crystals is presented. at first, the displacement-based forms of elastic wave equations are derived and then the forms are discretized using finite difference method. so the new algorithm is called the displacement-based finite difference time domain (dbfdtd). three numerical examples are computed with this met...

A novel 32-element Doppler sonar system was deployed to observe waves and currents over a km-scale area of the open ocean. The measurements cover a pie-shaped area about 1.5 km in range by 45 degrees azimuth, with 7.5 m by 1.3 degree resolution. Acoustic sampling every 2.5 seconds over the entire area provides detailed directional wave spectra and simultaneously the response of the underlying f...

Wave motion in disordered Faraday waves is analysed in terms of oscillons or quasi-particles. The motion of these oscillons is measured using particle tracking tools and it is compared with the motion of fluid particles on the water surface. Both the real floating particles and the oscillons, representing the collective fluid motion, show Brownian-type dispersion exhibiting ballistic and diffus...

by growing the population and need for settlement, many cities have been built on soft sediments and seismic areas. it emphasizes the need for a careful and reliable assessment of site effect phenomena. beyond the methods of studying site effects, microtremor recordings has become popular over the last decades as it offers a convenient, practical and low cost tool to be used in urbanized areas....

ground vibrations during an earthquake can severely damage structures and equipments housed in them. many factors including earthquake magnitude, distance from the fault or epicenter, duration of strong shaking, soil condition of the site, and the frequency content of the motion define the properties of ground motion and its amplification. a deep understanding of the effects of these factors on...