amplitudes of seismic waves decrease with distance according to anelastic properties of the earth and geometrical spreading. the attenuation of ground-motion amplitudes in the frequency domain is an important problem in engineering seismology. it is of particular practical interest in the regions such as zagros (iran). the zagros fold- thrust belt, as a part of alpine- himalayan orogenic belt i...

The present study is concerned with the variational principle and plane wave propagation in double porous thermoelastic infinite medium. Lord-Shulman theory [2] of thermoelasticity with one relaxation time has been used to investigate the problem. It is found that for two dimensional model, there exists four coupled longitudinal waves namely longitudinal wave (P), longitudinal thermal wave (T),...

seismic waves when crossing the earth in heterogeneous and anisotropic environments, having interaction. recognizing the impact of these factors on the seismograms help us to find out more information about interior of the earth. coda waves are the main reason for the random heterogeneities in earth. local earthquakes in the northeast region of iran with epicentral distance less than 200 km is ...

local site conditions have a strong effect on ground response during earthquakes. two important soil parameters that control the amplification effects of seismic motions by a soil column are the soil hysteretic damping ratio and shear wave velocity. this paper presents the results of in situ damping ratio measurements performed using continuous surface wave attenuation data at a site in semnan ...

A Lamb wave-based crack detection method for aluminum plates health monitoring is developed in this paper. Piezoelectric disks are employed to actuate and capture the Lamb wave signals. The position of crack is assumed to be aligned with the sensor and actuator.  Extraction of high quality experimental results of lamb wave propagation in a plate-like structure is considerably complicated due to...

[1] We constrain the spatial variation of P‐wave (tP*) and S‐wave (tS*) attenuation by inverting 190,000 teleseismic P‐ and S‐wave spectra up to 0.8 Hz. These spectra are derived from 250 deep earthquakes recorded at 880 broadband global and regional network stations. The variance and ratios of tP* and tS* values are consistent with PREM’s upper mantle velocity and Q structures and conventional...

Determinations of shear wave speeds of sound and attenuation coefficients are reported for soft tissues, a silicone rubber reference material, and a gel used in manufacturing ultrasonically tissue-mimicking materials. Fresh bovine tissues were investigated, including calfskin, liver, cardiac muscle, and striated muscle. Because of the very large shear wave attenuation coefficients, reasonably a...

The reported compressional wave speed dispersion and attenuation could be explained by a modified gap stiffness model incorporated into the Biot model (the BIMGS model). In contrast, shear wave speed dispersion and attenuation have not been investigated in detail. No measurements of shear wave speed dispersion have been reported, and only Brunson's data provide the frequency characteristics of ...

A of seismic waves is sensitive to the physical properties of the subsurface and has been observed in vertical seismic profiling (VSP) and reflection data. De et al. (1994) report measurements of the Pand S-wave quality factors from VSP surveys and sonic logs. Klimentos (1995) measures compressional and shear attenuation from sonic logs in sandstone formations with variable oil, water, and gas...