We present an analysis of migration effects on seismic reflection images of very shallow targets. Reflection objectives in engineering, groundwater, and environmental investigations commonly occur at depths between 2 and 50 m. Because the observation surface is near these imaged reflectors, optical distortion may be so small that migration will not have any effect on the seismic image and may t...

[1] We demonstrate that the coherent information about the Earth structure can be extracted from the ambient seismic noise. We compute cross-correlations of vertical component records of several days of seismic noise at different pairs of stations separated by distances from about one hundred to more than two thousand kilometers. Coherent broadband dispersive wavetrains clearly emerge with grou...

Seismic integration schemes aim to incorporate the rock mass response provided by the historical seismic activity to improve the ability of numerical models to reproduce future response to mining. Up to now, integration schemes considered the events using quasi-static models. This paper presents case studies that consider some of the seismic and modelling issues needed to extend these schemes t...

SUMMARY It has recently been shown that correlations of seismic noise can contain significant information about the Green's function along the station profile. Using an array of 38 temporary broadband stations located in Finland between September 1998 and March 1999, we study the resulting 703 noise correlations to understand how they are influenced by the directivity of the noise field. The la...

Seismic images reconstructed by migration from seismic data recorded at the surface represent the earth structure at every location in the subsurface. The data are remapped into the subsurface by using a wave equation and an estimate of the earth velocity. The velocity model is of great importance for obtaining accurate seismic images and for understanding the subsurface reservoir properties an...

Ultrasonic laboratory measurements of seismic compressional velocities (Vp) carried out on rock samples encompasing a wide range of metamorphic grades and lithologies from the Betic chain are presented. Measurements were performed at a high confining pressure on a total of 12 representative samples of the Alboran Domain (Internal Betics). P-wave mean velocities, referred to pressure conditions ...

[1] A joint interpretation of swath bathymetric, seismic refraction, wide-angle reflection, and multichannel seismic data was used to derive a detailed tomographic image of the Nazca–South America subduction zone system offshore southern Arauco peninsula, Chile at 38 S. Here, the trench basin is filled with up to 2.2 km of sediments, and the Mocha Fracture Zone (FZ) is obliquely subducting unde...

S U M M A R Y Passive seismic methods using earthquakes can be applied for extracting body waves and obtaining information of subsurface structure. In this study, we retrieve direct and reflected plane waves by applying seismic interferometry to the recorded ground motion from a cluster of regional earthquakes. We apply upgoing/downgoing P/S wavefield decomposition, time windowing, and multidim...

Seismic studies using well-logging, refraction, and reflection methods were carried out in 1965 in conjunction with a core-sample drilling project in the Ewa Coastal Plain, Oahu, Hawaii. The seismic well-logging technique gave a complicated velocity-depth profile, with higher velocities associated with reef limestone and lower velocities associated with mud deposits. The seismic refraction meth...

The errors in plate motion azimuths inferred from shear wave splitting beneath any one tectonic plate are shown to be correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining...