Dispersion curves and small‐scale geophysics using noise cross‐correlation techniques

2007 ◽  
Vol 121 (5) ◽  
pp. 3101-3101
Author(s):  
Philippe Roux ◽  
Pierre Gouedard ◽  
Cecile Cornou
Keyword(s):  
Cross Correlation ◽  
Dispersion Curves ◽  
Small Scale ◽  
Correlation Techniques ◽  
Noise Cross Correlation

The Small‐Scale Clustering of Luminous Red Galaxies via Cross‐Correlation Techniques

2005 ◽  
Vol 619 (1) ◽  
pp. 178-192 ◽  
Author(s):  
Daniel J. Eisenstein ◽  
Michael Blanton ◽  
Idit Zehavi ◽  
Neta Bahcall ◽  
Jon Brinkmann ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Small Scale ◽  
Luminous Red Galaxies ◽  
Correlation Techniques ◽  
Red Galaxies

S-waves profiles from noise cross correlation at small scale

2009 ◽  
Vol 105 (3-4) ◽  
pp. 161-170 ◽  
Author(s):  
C. Nunziata ◽  
G. De Nisco ◽  
G.F. Panza
Keyword(s):  
Cross Correlation ◽  
Small Scale ◽  
S Waves ◽  
Noise Cross Correlation

Infrared Techniques for Measuring Ocean Surface Processes

2008 ◽  
Vol 25 (2) ◽  
pp. 307-326 ◽  
Author(s):  
Fabrice Veron ◽  
W. Kendall Melville ◽  
Luc Lenain
Keyword(s):  
Cross Correlation ◽  
Field Experiments ◽  
Measurement Techniques ◽  
Ocean Surface ◽  
Surface Velocity ◽  
Surface Processes ◽  
Small Scale ◽  
Surface Renewal ◽  
Correlation Techniques ◽  
Infrared Techniques

Abstract Ocean surface processes, and air–sea interaction in general, have recently received increased attention because it is now accepted that small-scale surface phenomena can play a crucial role in the air–sea fluxes of heat, mass, and momentum, with important implications for weather and climate studies. Yet, despite good progress in recent years, the air–sea interface and the adjacent atmospheric and marine boundary layers have proven to be difficult to measure in all but the most benign conditions. This has led to the need for novel measurement techniques to quantify processes of air–sea interaction. Here the authors present infrared techniques aimed at simultaneously studying multiple aspects of the air–sea interface and air–sea fluxes. The instrumentation was tested and deployed during several field experiments from Research Platform (R/P) FLIP and Scripps pier. It is shown that these techniques permit the detailed study of the ocean surface temperature and velocity fields. In particular, it is shown that cross-correlation techniques typically used in particle image velocimetry can be used to infer the ocean surface velocity field from passive infrared temperature images. In addition, when conditions make cross-correlation techniques less effective, an active infrared marking and tracking technique [which will be called thermal marker velocimetry (TMV)] can be successfully used to measure the surface velocity and its spatial and temporal derivatives. The thermal marker velocimetry technique also provides estimates of the heat transfer velocity and surface renewal frequencies. Finally, infrared altimetry is used to complement the temperature and kinematic data obtained from passive imagery and active marking. The data obtained during the testing and deployment of this instrumentation provide a novel description of the kinematics of the surface of the ocean.

scholarly journals Velocity structure and radial anisotropy of the lithosphere in southern Madagascar from surface wave dispersion

2020 ◽  
Vol 224 (3) ◽  
pp. 1930-1944 ◽  
Author(s):  
E J Rindraharisaona ◽  
F Tilmann ◽  
X Yuan ◽  
J Dreiling ◽  
J Giese ◽  
...  
Keyword(s):  
Receiver Functions ◽  
Dispersion Curves ◽  
Eastern Coast ◽  
Small Scale ◽  
Seismic Structure ◽  
Lithospheric Thickness ◽  
Velocity Models ◽  
Phase Velocities ◽  
Maximum Value ◽  
Radial Anisotropy

SUMMARY We investigate the upper mantle seismic structure beneath southern Madagascar and infer the imprint of geodynamic events since Madagascar’s break-up from Africa and India and earlier rifting episodes. Rayleigh and Love wave phase velocities along a profile across southern Madagascar were determined by application of the two-station method to teleseismic earthquake data. For shorter periods (<20 s), these data were supplemented by previously published dispersion curves determined from ambient noise correlation. First, tomographic models of the phase velocities were determined. In a second step, 1-D models of SV and SH wave velocities were inverted based on the dispersion curves extracted from the tomographic models. As the lithospheric mantle is represented by high velocities we identify the lithosphere–asthenosphere boundary by the strongest negative velocity gradient. Finally, the radial anisotropy (RA) is derived from the difference between the SV and SH velocity models. An additional constraint on the lithospheric thickness is provided by the presence of a negative conversion seen in S receiver functions, which results in comparable estimates under most of Madagascar. We infer a lithospheric thickness of 110−150 km beneath southern Madagascar, significantly thinner than beneath the mobile belts in East Africa (150−200 km), where the crust is of comparable age and which were located close to Madagascar in Gondwanaland. The lithospheric thickness is correlated with the geological domains. The thinnest lithosphere (∼110 km) is found beneath the Morondava basin. The pre-breakup Karoo failed rifting, the rifting and breakup of Gondwanaland have likely thinned the lithosphere there. The thickness of the lithosphere in the Proterozoic terranes (Androyen and Anosyen domains) ranges from 125 to 140 km, which is still ∼30 km thinner than in the Mozambique belt in Tanzania. The lithosphere is the thickest beneath Ikalamavony domain (Proterozoic) and the west part of the Antananarivo domain (Archean) with a thickness of ∼150 km. Below the eastern part of Archean domain the lithosphere thickness reduces to ∼130 km. The lithosphere below the entire profile is characterized by positive RA. The strongest RA is observed in the uppermost mantle beneath the Morondava basin (maximum value of ∼9 per cent), which is understandable from the strong stretching that the basin was exposed to during the Karoo and subsequent rifting episode. Anisotropy is still significantly positive below the Proterozoic (maximum value of ∼5 per cent) and Archean (maximum value of ∼6 per cent) domains, which may result from lithospheric extension during the Mesozoic and/or thereafter. In the asthenosphere, a positive RA is observed beneath the eastern part Morondava sedimentary basin and the Proterozoic domain, indicating a horizontal asthenospheric flow pattern. Negative RA is found beneath the Archean in the east, suggesting a small-scale asthenospheric upwelling, consistent with previous studies. Alternatively, the relatively high shear wave velocity in the asthenosphere in this region indicate that the negative RA could be associated to the Réunion mantle plume, at least beneath the volcanic formation, along the eastern coast.

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