[1] High-pressure assemblages of subducted oceanic crust are denser than the normal upper mantle but less dense than the uppermost lower mantle. Thus subducted oceanic crust may accumulate at the base of the upper mantle. Direct observational evidence for this hypothesis, however, remains elusive. We present an analysis of a negativepolarity shear wave converted from compressional wave at a sei...

seismic piezocone device (scptu) together with resonant column and cyclic triaxial test apparatus are employed to measure small strain shear modulus (g0) of carbonate sandy and clayey soils of southern coasts of iran. a large area of southern regions of iran is formed from clay, silt and sand. in this study, maximum shear modulus that is derived from both field (by seismic piezocone) and labora...

the stolt (f-k) migration algorithm is a direct (i.e. non-recursive) fourier-domain technique based on a change of variables (or equivalently, a mapping) that converts the input spectrum to the output spectrum. the algorithm is simple and efficient but limited to constant velocity. a v(z)(f-k) migration method, capable of very high accuracy for vertical variations of velocity, can be formulated...

The deep crustal and upper mantle structure of the Yilgarn Craton is investigated in this study using receiver-function analysis of teleseismic earthquake records from temporary stations. Two lines of stations were deployed, the main transect ran between Perth and Kalgoorlie, and a second line of stations ran across the east Yilgarn Craton 200 km to the north of Kalgoorlie. The broadband instru...

[1] Because of short recurrence times and known locations, small repeating earthquakes present a rare predictable opportunity for detailed field observations. They are used to study fault creeping velocities, earthquake nucleation, stress drops, and other aspects of tectonophysics, earthquake mechanics, and seismology. An intriguing observation about repeating earthquakes is their scaling of re...

Due to the introduction of Eurocode 8, the structural design for seismic and dynamic effects has become more significant in Hungary. This has emphasized the need for more effort to describe the behavior of structures under these conditions. Soil conditions have a significant effect on the response of structures by modifying the stiffness and damping of the soil-structural system and by modifyin...

I extend the interferometric interpolation of ocean bottom seismic (OBS) data from two dimensional data to 3D data. The sparse OBS data are interferometrically correlated with the model-based Green’s functions for the sea-floor model to generate the densely recorded OBS traces, and a local matching filter is applied to reduce the artifacts in the interpolated data. Information about the source ...

The numerous recent laboratory and field examples show the potential benefits of seismic low frequencies in hydrocarbon detection. To simulate the frequency-dependent response of turbidite reservoirs in JZ Area, the Bohai Sea, China, and then implement frequency-dependent detection of the hydrocarbon accumulation based on low frequencies, we expanded a diffusive and viscous wave equation (DVWE)...

Ž . We investigate seismic layering i.e., discontinuities, regions of anomalous velocity gradients, and anisotropy and its Ž . lateral variability in the upper mantle by comparing seismic models from three tectonic regions: old ;100 Ma Pacific Ž . plate, younger ;40 Ma Philippine Sea plate, and Precambrian western Australia. These models were constructed by combining two data sets: ScS-reflecti...

Waveform inversion is a velocity-model-building technique based on full waveforms as the input and seismic wavefields as the information carrier. Conventional waveform inversion is implemented in the data domain. However, similar techniques referred to as image-domain wavefield tomography can be formulated in the image domain and use a seismic image as the input and seismic wavefields as the in...