the goal of this laboratory study is to investigate the effect of pore shapes on seismic wave velocities in carbonate rocks under reservoir conditions. in this research, 41 core plugs of carbonate rocks from oil fields of the southwest of iran were prepared. the compressional and shear wave velocities were measured in both dry and brine saturated samples under several pressures especially reser...

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 ...

north-east khorasan is one of the most active regions in the world because of is setting on the alpine-himalayan belt. historical and geological backgrounds suggest that this region has experienced many destructive earthquakes throughout history. compared with the historical background, the seismicity of the region, in the present century, is better known both from the macroseismic and instrume...

Building accurate interval velocity models is critically important for seismic imaging and amplitude inversion. Here, we adapt the so-called “PP+PS=SS” method to devise an exact technique for constructing the interval traveltime-offset function in a target zone beneath a horizontally layered overburden. The algorithm is designed for arbitrarily anisotropic target layers, but the overburden is a...

Anisotropy parameters are obtained by anisotropic velocity analysis performed on Blackfoot P-wave reflection-seismic data, in combination with sonic-log data. First, the line was processed with ProMAX seismic data-processing software using a sequence of conventional algorithms without taking anisotropy into account, in order to choose proper analysis points and horizons with confidence. Then, a...

A model of thermoelastic properties for a chemically homogeneous adiabatic lower mantle is calculated. Constraints provided by this model are used in convection models to study dynamics of a chemically distinct layer at the bottom of the mantle. We find that the layer must be at least 2% denser than the overlying mantle to survive for a geologically significant period of time. Realistic decreas...

We present a hybrid method to produce a velocity model of the Earth’s crust using evolutionary and seismic tomography algorithms. This method takes advantage of the global search ability of an evolution strategy and the quick convergence of an iterative three-dimensional seismic tomography technique to generate a model of the Earth’s crustal structure from recorded arrival times of wave fronts ...

Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical obs...

The upper lithospheric structure from the Pilbara Craton, across the Capricorn Orogen, to the northern Yilgarn Craton is determined from high-fidelity broadband seismic data. Three-component temporary stations were deployed in a line running southwards from Marble Bar, Western Australia, at approximately 118 E longitude. They were in position between July and October 2000. Receiver functions ar...

We have developed an inversion formulation for velocity and attenuation structure using seismic attributes, including envelope amplitude, instantaneous frequency and arrival times of selected seismic phases. We refer to this approach as AFT inversion for amplitude, (instantaneous) frequency and time. Complex trace analysis is used to extract the different seismic attributes. The instantaneous f...