Analysis of the refracted arrivals on a seismic reflection profile recorded along the wall of a tunnel at an iron mine near Thabazimbi, South Africa, shows variations in P-wave velocity in dolomite away from the de-stressed zone that vary between 4.4 and 7.2 kmrs, though values greater than 5.8 kmrs predominate along most of the profile. The seismic velocities at the tunnel wall, however, vary ...

The main purpose of the paper is the numerical analysis of seismic site effects in Caracas (Venezuela). The analysis is performed considering the Boundary Element Method in the frequency domain. A numerical model including a part of the local topography is considered, it involves a deep alluvial deposit on an elastic bedrock. The amplification of seismic motion (SH-waves, weak motion) is analyz...

the reservoir’s diff erential pressure. Most samples are initially humidifi ed to avoid the softening matrix eff ect of initial introduction of moisture in the pore space. Small amounts of water (less than 1% of the pore volume) can reduce the bulk and shear moduli of the rock signifi cantly. Th e data in this paper are the estimated mean properties (markers in the plots) and one standard devia...

Resonance frequencies can provide useful information on the deformation occurring during fracturing experiments or CO2 management, complementary to the microseismic event distribution. An accurate time-frequency representation is of crucial importance prior to interpreting the cause of resonance frequencies during microseismic experiments. The popular methods of Short-Time Fourier Transform (ST...

As a powerfully diagnostic tool for structural interpretation, reservoir characterization, and hydrocarbon detection, quality factor Q provides useful information in seismic processing and interpretation. Popular methods, like the spectral ratio (SR) method, central frequency shift (CFS) method and peak frequency shift (PFS) method, have their respective limitations in dealing with field seismi...

An ever present goal of seismic processing and inversion is to extract meaningful geology information from seismic data. The simplest possibility is to invert for seismic impedances, or, considering density constant, invert for velocities. Here I use a micro genetic algorithm program to achieve this goal. I use a real sonic log to compute a synthetic seismic trace and then use that trace as inp...

contrary to the long period ground motions that can be predicted and estimated, high frequency ground motions have random character and behave stochastically. stochastic modeling methods are usually used for the modeling of high frequency ground motions where there are not strong ground motion records. stochastic methods are of two kinds: in the first one, the seismic source is considered as a ...