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Titolo:
Small-scale structure of lithosphere-asthenosphere beneath Gauribidanur Seismic array deduced from amplitude and phase fluctuations
Autore:
Tripathi, JN;
Indirizzi:
Univ Allahabad, Dept Earth & Planetary Sci, Allahabad 211002, Uttar Pradesh, India Univ Allahabad Allahabad Uttar Pradesh India 211002 Uttar Pradesh, India
Titolo Testata:
JOURNAL OF GEODYNAMICS
fascicolo: 4, volume: 31, anno: 2001,
pagine: 411 - 428
SICI:
0264-3707(200105)31:4<411:SSOLBG>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
UPPER MANTLE STRUCTURE; WAVE SCATTERING; TURBULENT MEDIA; P-WAVES; ATTENUATION; PROPAGATION; NORSAR; LASA; HETEROGENEITIES; INHOMOGENEITIES;
Keywords:
GBA; heterogeneities; rms; scattering; transverse coherence functions;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Tripathi, JN Univ Allahabad, Dept Earth & Planetary Sci, Allahabad 211002,Uttar Pradesh, India Univ Allahabad Allahabad Uttar Pradesh India 211002 h, India
Citazione:
J.N. Tripathi, "Small-scale structure of lithosphere-asthenosphere beneath Gauribidanur Seismic array deduced from amplitude and phase fluctuations", J GEODYN, 31(4), 2001, pp. 411-428

Abstract

The cross coherence function between log amplitude and phase (or travel time) has been analyzed along with the transverse coherence functions of log amplitude and phase in order to estimate the statistical distribution of heterogeneities beneath the Gauribidanur Seismic array (CBA). The power spectra of the P-wave velocity variations can be estimated under the array with the help of the transverse coherence functions (TCFs). The data of 72 earthquakes have been used to calculate the three TCFs (of phase, log amplitude and cross-coherence). The central frequency is 2 Hz. The measured root meansquare (rms) log amplitude fluctuation is 0.40 and the rms phase fluctuation is 0.88. An overlapping two-layer model has been obtained for lithosphere and asthenosphere heterogeneities beneath GBA with different power law spectra. The upper layer, in which the heterogeneities are defined by Gaussian correlation function extends from the surface to about 160 km depth whilethe lower layer, in which the heterogeneities are defined by exponential correlation function extends from 16 to 280 km. The rms P-wave velocity variation has been estimated in the range of 0.3-1.5%. Clustering off cracks orintrusions may be responsible for the small-scale heterogeneities while temperature or compositional heterogeneities may be the cause of large-scale wave heterogeneities. (C) 2001 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 19:35:50