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...

Several seismic phases that scattered within a few hundred kilometers of the base of the mantle are observed in a very dense seismic section. The Los Angeles Region Seismic Experiment passive phase array was composed of 88 seismometers placed along a 175 km profile. Records from two deep earthquakes in Tonga and one earthquake near Honshu, Japan show a secondary arrival between clear P and PcP ...

[1] Since it has already been demonstrated that point-topoint seismic propagation Green Functions can be extracted from seismic noise, it should be possible to image Earth structure using the ambient noise field. Seismic noise data from 148 broadband seismic stations in Southern California were used to extract the surface wave arrival-times between all station pairs in the network. The seismic ...

SUMMARY Eikonal tomography has become a key approach to image lithospheric structures with surface waves recorded by dense regional arrays. Its main advantage is that phase velocities can be determined directly from measurements without resolving tomographic inverse problem. Here, we apply new smoothing spline eikonal selection of 40 large (Mw larger than 6.5) teleseismic events the permanent s...

Full waveform inversion of a p-r marine data set from the Gulf of Mexico provides estimates of the longwavelength P-wave background velocity, anisotropic seismic source, and three high-frequency elastic parameter refiectivities that explain 70% of the total seismic data and 90% of the data in an interval around the gas sand target. The forward simulator is based on a planewave viscoelastic mode...

it is well established that the seismic ground response of surface topographies may differ from those of free field motion during earthquakes. complex nature of seismic wave scattering by topographical structures can only be solved accurately and economically using advanced numerical methods under realistic conditions. among the numerical methods, the boundary element is a powerful numerical te...

Overburden layers continue to be a problem for recording and analyzing information in seismic surveys. This study aims to examine the effects of overburden layers on seismic wave propagation and imaging. In the investigation, we look at the effect of low velocity, low density overburden on seismic imaging. To investigate this problem, a finite difference elastic wave modelling study was conduct...

In transversely isotropic media with a vertical axis of symmetry (VTI media), we can represent the image in vertical time, as opposed to depth, thus eliminating the inherent ambiguity of resolving the vertical P-wave velocity from surface seismic data. In this new (x − τ )-domain, the raytracing and eikonal equations are completely independent of the vertical P-wave velocity, on the condition t...

We have determined a detailed three-dimensional P wave velocity structure of the Japan subduction zone to 500-km depth by inverting local, regional, and teleseismic data simultaneously. We used 45,318 P wave arrivals from 1241 shallow and deep earthquakes which occurred in and around the Japan Islands. The arrival times are recorded by the Japan University Seismic Network which covers the entir...

Seismic techniques, which are known as nondestructive geophysical methods, are commonly used by engineers working in various fields such as mining, civil, and geotechnical engineering. They are frequently employed to investigate certain properties of rocks. Ultrasonic measurements can be applied in various application areas such as rockbolt reinforcement1, blasting efficiencies in the rock mass...