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...

The disadvantages of conventional seismic tomographic ray tracing and inversion by calculus-based techniques include the assumption of a single ray path for each source– receiver pair, the non-inclusion of head waves, long computation times, and the difficulty in finding ray paths in a complicated velocity distribution. A ray-tracing algorithm is therefore developed using the reciprocity princi...

S U M M A R Y The seismic structure of large igneous provinces provides unique constraints on the nature of their parental mantle, allowing us to investigate past mantle dynamics from present crustal structure. To exploit this crust–mantle connection, however, it is prerequisite to quantify the uncertainty of a crustal velocity model, as it could suffer from considerable velocity–depth ambiguit...

[1] Using two continuum models of rate-and-state faults, one with a weaker patch and the other with rheological transition from steady state velocity-weakening to velocity-strengthening friction, we simulate several scenarios of spontaneous earthquake nucleation plausible for natural faults, investigate their response to static shear stress steps, and infer the corresponding aftershock rates. O...

[1] We determine the geometry and geographic distribution of a very low velocity province (VLVP) at the base of the Earth’s mantle beneath the South Atlantic and Indian Oceans, based on waveform modeling and travel time analysis of seismic data recorded in Africa. Our data sets consist of SH, ScS, SHdiff, SKS, and SKKS phases recorded at two temporary broadband PASSCAL seismic arrays in Africa,...

This paper presents a new interpretation of the geometry of Triassic alignment of J. Sidi Mahdi –J. Zitoun in Medjerda Valley Plain (Northern Tunisia) based on detailed analysis of gravity and seismic reflection data. The main results of gravity analysis do not show a distinguish gravity anomaly over Triassic evaporites bodies. The positive gravity anomaly seems to be related to the entire stru...

Subsurface rock strata are often conceptualized in three dimensions as depth surfaces, or horizons. By picking the corresponding reflection event from 3-D seismic data, an approximate “seismic horizon” can be obtained, but in general the inconsistencies in the approximation are nontrivial. Picks from well log data give the depth to the horizon to high accuracy, but only at a few points. To achi...

We quantify natural methane hydrate reservoirs by generating synthetic seismic traces and comparing them to real seismic data: if the synthetic matches the observed data, then the reservoir properties and conditions used in synthetic modeling might be the same as the actual, in-situ reservoir conditions. This approach is model-based: it uses rock physics equations that link the porosity and min...

Most seismological models for the interior of Mars lack an upper mantle low velocity zone. However, there is expected to be a large thermal gradient across the stagnant conductive lid (lithosphere) of Mars. This gradient should tend to decrease elastic wave velocities with increasing depth, with this effect dominating the opposing tendency caused by increasing pressure with depth because Mars h...

results of velocity structure modeling in the earth's crust using a comparison approach of receiver function analysis and joint inversion of receiver functions with surface wave dispersion data are presented in this paper. seismograms of the teleseismic events that have been recorded on a broadband seismic station in the central alborz were used for data processing. velocity models that we...