it is very important to study and simulate s-wave structure for near surface (alluvium parts, in particular) owing to its direct relationship to urban facilities in geotechnical and earthquake engineering studies. so, in seismic microzonation, the first step is to study and identify s-wave pattern in alluvium in order to categorize different parts of cites according to s-wave velocity. current ...

Although previous studies have related variations in environmental noise levels with alterations in communication behaviors of birds, little work has investigated the potential long-term implications of living or breeding in noisy habitats. However, noise has the potential to reduce fitness, both directly (because it is a physiological stressor) and indirectly (by masking important vocalization...

Full waveform inversion with frequency sweeping cannot start from zero frequency because of the lack of low-frequency data, requiring a good starting model. We study a different iterative scheme where the notion of proximity of two traces is not the usual least-squares distance, but instead involves registration as in image processing. In order to create transported data, we introduce a nonconv...

We present a new method for estimating the number and arrival times for overlapping signals with a priori known shape from noisy observations received by a sensor. The method is based on a recently developed eigenstructure technique for multitarget direction finding with passive antenna arrays and exploits the structure of the recejved signal covariance matrix. This problem is impriani in vario...

We discuss three approaches to seismic interferometry and compare their underlying assumptions. In the first approach the reflection response is reconstructed by cross-correlating the responses of many uncorrelated noise sources. In the second approach a depth image is obtained from the response of a single source, recorded by many receivers. In the third approach the Green’s function is recons...

A wireless sensor network that studies relatively widespread phenomena (such as a contaminant flow or a seismic disturbance) may be called upon to provide a description of the boundary of the phenomenon (either a contour or some bounding box). In such cases, it may be necessary for each node to locally determine whether it lies at (or near) the edge of the phenomenon. In this paper, we show tha...

Several lines of evidence from analysis of impact craters and other morphological features on Ida indicate the asteroid surface is covered with a thin layer of regolith that probably grades downward into less well-sorted rubble/megaregolith. This transition with depth is too gradational or occurs too close to the surface to be expressed in crater morphology at available resolution. Gravitationa...

Inverse theory concerns the problem of making inferences about physical systems from indirect noisy measurements. Information about the errors in the observations is essential to solve any inverse problem, otherwise it is impossible to say when a feature “fits the data.” In practice, however, one seldom has a direct estimate of the data errors. We exploit the trade-off between data prediction a...

Noisy data are often resigned to the “too hard” basket, and an expectation exists that incremental improvements in processing effort and technology will slowly recover interpretation confidence over a long period of time. Fortunately, acquisition technology has improved significantly in recent years, and high-density 3D acquisition methods (multi-streamer, OBC, and land) are now able to provide...