نتایج جستجو برای: seismic temporal resolution

تعداد نتایج: 539288  

2015
Peter Gerstoft

Although naturally occurring vibrations have proven useful to probe the subsurface, the vibrations caused by traffic have not been explored much. Such data, however, are less sensitive to weather and low visibility compared to some common out-of-road traffic sensing systems. We study traffic-generated seismic noise measured by an array of 5200 geophones that covered a 7 × 10 km area in Long Bea...

2007
I. RIVERA RABELO S. M. LUTHI L. J. van VLIET

We developed a simple method to parameterise fluvial point bars, which are common sedimentary deposits in meandering river environments. The method needs four points defining the point bar and is based on high-resolution seismic data. A model geometry is compared with the real point bar geometry. We optimise the model parameters by minimizing the error in the area covered by both objects. The m...

Journal: :Frontiers in Earth Science 2022

The lacustrine deposition with continuity and chronological reliability is one of the important archives to establish paleo-seismic sequences. In this study, sediment short cores were obtained from Lake Mugeco, located in Selaha section Xianshuihe fault zone on southeastern margin Tibetan Plateau. chronology established using 210 Pb/ 137 Cs AMS 14 C dating results. Seismic events are identified...

2016
Vaneeta Devi

The Spectral decomposition of seismic data was incepted earlier in the second half of the 19th century, howeverlimited research work has been done in this filed because of lack of availability of advancetools/ techniques for analysis of transient signal like earthquake time historyrecords. Although, there are several conventional techniques like Fourier Transform (FT),Fourier Series (FS)that ar...

2013
Gregory Ely Shuchin Aeron Ning Hao Misha E. Kilmer

In this paper we present novel strategies for completion of 5D pre-stack seismic data, viewed as a 5D tensor or as a set of 4D tensors across temporal frequencies. In contrast to existing complexity penalized algorithms for seismic data completion, which employ matrix analogues of tensor decompositions such as HOSVD or use overlapped Schatten norms from different unfoldings (or matricization) o...

Journal: :iranian journal of nuclear medicine 2006
arman rahmim

this paper intends to compare the abilities of the two major imaging modalities in nuclear medicine imaging: positron emission tomography (pet) and single photon emission computed tomography (spect). the motivations are many-fold: (i) to gain a better understanding of the strengths and limitations of the two imaging modalities in the context of recent and ongoing developments in hardware and so...

2001
James G. Berryman

Resolution matrices are useful in seismic tomography because they allow us to evaluate the information content of reconstructed images. Techniques based on the multiplicity of equivalent exact formulas that may be used to define the resolution matrices have been used previously by the author to design algorithms that avoid the need for any singular value decomposition of the ray-path matrix. An...

Journal: :iranian journal of nuclear medicine 2005
ahmad bitarafan rajabi hossein rajabi seyed hasan firoozabadi nahid yaghoobi feridoon rastgoo

introduction: acceptance test is a necessary procedure after spect system installation. the goal of this test is to reveal system's present condition, to compare it with manufacturer's specifications and also as a base for later tests. methods: this study investigated four spect systems in tehran. all of the quality control tests are performed on the basis of nema and iaea recommendations and b...

2007
Warner Marzocchi Jacopo Selva

We investigate on the capability of the strongest earthquakes to modify significantly the seismicity in a wide spatio-temporal window. In particular, we show that the strongest earthquakes of last century were probably able to influence the seismicity at large spatio-temporal distances, extending their reach over thousand of kilometers and decades later. We report statistically significant diff...

2007
Philippe Steeghs Guy Drijkoningen

The variation of frequency content with time is an important seismo-stratigraphic indicator. This paper discusses the analysis of local frequency content of seismic reeection data with quadratic joint time-frequency representations. Signal adaptive quadratic time-frequency representations have considerably better time-frequency localization properties (resolution) than more standard approaches ...

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