Performance based seismic design (PBSD) is an alternative to code based approaches to design or evaluation of structures that fail to yield a more direct relationship between a seismic event and the corresponding structural performance of a building; this generally leads to over-conservatism. This paper presents a case study on the alternative procedures used in the performance based design of ...

In addition to vertical time shifts commonly observed in time-lapse seismic images, horizontal displacements are apparent as well. These apparent horizontal displacements may be small relatively to seismic wavelengths, perhaps only 5 m at depths of 5 km, but they consistently suggest an outward lateral expansion of images away from a compacting reservoir. It is well known that apparent vertical...

seismic refraction and downhole survey were employed to study dynamic characteristics of subsurface materials in bam city, southeast of iran. the data acquisition was performed at 160 p and s-wave refraction stations and 15 boreholes in the city. to derive velocity depth sections along these profiles as well as to perform downhole diagrams, seisimager software was used. based on the obtained va...

This paper explores the relationship between velocity uncertainty and AVO-related seismic attributes in a dataset from the Blake Outer Ridge, offshore from Florida and Georgia. From an initial velocity model, several realizations were generated that are perturbations of the original velocity model. Prestack wave-equation migration was applied to the data for each velocity realization. In the mi...

Joint inversion of different geophysical datasets is an effective way to eliminate non-uniqueness in geophysical inversion problems. In this paper, we focus on a case study of joint inversion of seismic traveltime and gravity observations. The results are encouraging and we can have confidence that, comparing traveltime tomography alone, joint inversion of seismic traveltime and gravity data im...

The seismic phase PKJKP, which traverses the inner core as a shear wave and would provide direct evidence for its solidity, has been difficult to detect. Using stacked broadband records from the Grafenberg array in Germany, we documented a high signal-to-noise phase, the arrival time and slowness of which agree with theoretical predictions for PKJKP. The back azimuth of this arrival is also con...

The traveltimes of first arriving seismic rays through most velocity structures can be computed rapidly on a three-dimensional numerical grid by finite-difference extrapolation. Head waves are properly treated and shadow zones are filled by the appropriate diffractions. Differences of less than 0.11 percent are found between the results of this technique and ray tracing for a complex but smooth...

Complex seismic signatures are generated due to the complexity of the subsurface which is difficult to interpret. In the present study, an attempt has been made to model the complex subsurface using the Ray tracing modeling technique. Add to this, for the imaging of these geological features, Kirchhoff’s prestack depth migration is applied over the synthetic common shot gather dataset. It is fo...

geophysical techniques remain the only ways to remotely and non-destructively sense the earth’s near subsurface and as such have the most promising prospect for rapid and accurate detection of underground tunnels. today, electrical resistivity and seismic refraction geophysical methods have been greatly developed to identify structures and underground cavities. in this study, the ability of the...

The end goal of any solid Earth study is to better constrain physical parameters of the Earth (e.g. viscosity, temperature, and mineral composition). As we are unable to directly measure many of these quantities, past a few kilometers in depth, we must content ourselves with indirect estimates by way of experiment and theory. Just as geochemists do this by way of compositional deviations from p...