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Titolo:
Imaging upper-mantle discontinuity topography using underside-reflection data
Autore:
Neele, F; de Regt, H;
Indirizzi:
Univ Utrecht, Dept Theoret Geophys, NL-3508 TA Utrecht, Netherlands Univ Utrecht Utrecht Netherlands NL-3508 TA 3508 TA Utrecht, Netherlands
Titolo Testata:
GEOPHYSICAL JOURNAL INTERNATIONAL
fascicolo: 1, volume: 137, anno: 1999,
pagine: 91 - 106
SICI:
0956-540X(199904)137:1<91:IUDTUU>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
MULTIFOLD PATH-INTEGRALS; SEISMIC DISCONTINUITIES; 660-KM DISCONTINUITY; VELOCITY STRUCTURE; THERMAL STRUCTURE; SUBDUCTION ZONE; AMPLITUDE DATA; TRAVEL-TIMES; SEISMOGRAMS; TOMOGRAPHY;
Keywords:
410 discontinuity; 670 discontinuity; upper mantle;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Neele, F TNO, Phys & Elect Lab, POB 96864, NL-2509 JG The Hague, Netherlands TNO POB 96864 The Hague Netherlands NL-2509 JG ague, Netherlands
Citazione:
F. Neele e H. de Regt, "Imaging upper-mantle discontinuity topography using underside-reflection data", GEOPHYS J I, 137(1), 1999, pp. 91-106

Abstract

This paper presents a method to invert underside-reflection (PdP or SdS arrivals) data for lateral depth variations of upper-mantle discontinuities, combining traveltime and amplitude data. The method greatly improves the resolution of small-scale undulations obtained by existing imaging methods and does not suffer from the long-wavelength biases that are likely to be present in currently available models. Existing inversion methods account for the large size of the Fresnel zone of underside reflections, but not for its complexity, arising from the mini-max traveltime nature of PP- and SS-related waves. This neglect results in long-wavelength artefacts from small-scale undulations of the discontinuities, obscuring true long-wavelength depth variations. The inversion method presented in this paper uses a complex-valued sensitivity kernel, derived from the representation of underside reflections through a Kirchhoff integral formulation. The sensitivity kernel accounts for the varying sensitivity of the waveforms to discontinuity structure over the Fresnel zone. The method is applied to a large, synthetic dataset. The data set consists of PdP amplitudes and traveltimes. The results show that the new inversion method resolves depth variations on a lateral scale that is smaller than the size of the Fresnel zone of individual underside reflections (but larger than the dominant wavelength), retaining the resolution of large-scale variations. The results presented here suggest thatthe discontinuity depth variations induced by slab penetration of the 670 discontinuity could be resolved by current broad-band P670P data sets.

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Documento generato il 26/09/20 alle ore 02:07:03