in this paper we are going to show the importance of mode identification in microtremor array analysis. the idea come from four concentric ambient noise array recordings with aperture 100 to 1000 meters, performed in southern urban area of tehran near the shrine of imam khomeini. these measurements were part of a comprehensive research project with the aim of determination of deep shear wave ve...

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....

Shear-wave velocity ( ) is an important parameter used for site characterization in geotechnical engineering. However, dispersion curve inversion is challenging for most inversion methods due to its high non-linearity and mix-determined trait. In order to overcome these problems, in this study, a joint inversion strategy is proposed based on the particle swarm optimization (PSO) algorithm. The ...

shear-wave velocity ( ) is an important parameter used for site characterization in geotechnical engineering. however, dispersion curve inversion is challenging for most inversion methods due to its high non-linearity and mix-determined trait. in order to overcome these problems, in this study, a joint inversion strategy is proposed based on the particle swarm optimization (pso) algorithm. the ...

We use the multi-channel analysis of surface waves (MASW) method to analyze synthetic seismic data calculated from models that produce very similar high-velocity dispersion curve gradients at low frequencies. The MASW dispersioncurve images of the Rayleigh wave were obtained from data calculated using simple layered models with high (2-layer) and gradual (10-layer) shear-wave velocity (Vs) vert...

We analyze seismic data using multi-channel analysis of surface waves (MASW) to invert multi-mode surface-wave dispersion curves into 1D vertical shear-wave velocity profiles. The dispersion-curve patterns of the Rayleigh wave are imaged using conventional methods and the high-resolution linear radon transform (HRLRT). Comparison of these imaging techniques shows that the HRLRT provides higher ...

[1] In order to use ambient seismic noise for mapping Earth’s structure, it is important to understand the spatiotemporal characteristics of the noise field. This study uses data collected during four austral winter months of 2002 to investigate New Zealand’s ambient seismic noise field in the double-ocean-wave-frequency range (0.1–0.3 Hz). It is shown via beamforming analysis that there are tw...

summarythe explanation of the elastic, or velocity structure of the earth has long been a goal of the world’s seismologists. for the first few decades of seismological research, the investigation on velocity structure was restricted to the determination of one-dimensional models of the solid earth and of various regions within it. seismologists are currently obtaining three dimensional velocity...

In this paper, the reflection of ultrasonic guided waves from simple dent in pipes has been investigated using finite element method and the relationship between reflection coefficient of these waves and deformation rate has been determined. Also, the effect of the parameters of wave generation source on the generated wave field has been investigated using normal modes expansion method. At firs...