rf method is now a well-known tool for studying crustal and upper mantle structure when such a complete data set is available. we compute p receiver functions to investigate the upper mantle discontinuity beneath the northwest of iran. we selected data from teleseismic events (mb ? 5.5, 30 ?>? > 95?) recorded from 1995 to 2008 at 8 three component short period stations from tabriz telemetry sei...

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The scalar median filter (SMF) is often used to reduce noise in scalar geophysical data. We present an extension of the SMF to a vector median filter (VMF) for suppressing noise contained in geophysical data represented by multidimensional, multicomponent vector fields. Although the SMF can be applied to each component of a vector field individually, the VMF is applied to all components simulta...

The automated approximation of solutions to differential equations which involve discontinuities across evolving surfaces is addressed. Finite element technology has developed to the point where it is now possible to model evolving discontinuities independently of the underlying mesh, which is particularly useful in simulating failure of solids. However, the approach remains tedious to program,...

We propose a new edge detection method that is effective on multivariate irregular data in any domain. The method is based on a local polynomial annihilation technique and can be characterized by its convergence to zero for any value away from discontinuities. The method is numerically cost efficient and entirely independent of any specific shape or complexity of boundaries. Application of the ...

[1] Seismic velocity discontinuities within the top 1000 km of the Earth beneath southern Africa are imaged by stacking about 1300 source-normalized broadband seismograms recorded by the Southern African Seismic Experiment. The Moho, 410, and 660 kilometer discontinuities are clearly detected. The mean mantle transition zone thickness is 245 km, essentially the same as the global average, sugge...

[1] Recent observations of ridge bathymetry suggest magmatic segmentation at fastand intermediatespreading centers is linked to the migration of the spreading axis over the mantle. At fastand intermediatespreading centers, Carbotte et al. (2004) observed that leading segments, those that are offset in the direction of ridge migration, are typically shallower (interpreted to be magmatically robu...

Introduction The description of a fault model includes the fault surfaces and associated tip lines, the fault network geometry, and the displacement geometry of faults. Fault surfaces are usually observed from seismic discontinuities, which include reflector breaks, flexures, and amplitude changes. These discontinuities can often have a regular appearance that corresponds to fault geometries fo...

As in two{dimensional computer vision, segmentation is one of the most important processes in 3{D vision. The recent availability of cost{e ective range imaging devices has simpli ed the problem of obtaining 3{D information directly from a scene. Range images are characterized by two principal types of discontinuities: step edges that represent discontinuities in depth, and roof (or trough) edg...

Microplasma welding is a less expensive alternative to laser welding in dental technology. The aim of the study was to highlight discontinuities present in the microplasma welded joints of dental base metal alloys by visual analysis. Five base metal alloys designated for fixed prostheses manufacture were selected for the experiments. Using these plates, preliminary tests were conducted by micro...