@article {Dagnino2014,
	title = {{Scale- and parameter-adaptive model-based gradient pre-conditioner for elastic full-waveform inversion}},
	journal = {Geophysical Journal International},
	volume = {198},
	number = {2},
	year = {2014},
	month = {jun},
	pages = {1130{\textendash}1142},
	publisher = {Oxford University Press},
	abstract = {We present a scale- and parameter-adaptive method to pre-condition the gradient of the parameters to be inverted in time-domain 2-D elastic full-waveform inversion (FWI). The proposed technique, which relies on a change of variables of the model parameters, allows to balance the value of the gradient of the Lam{\'e} parameters and density throughout the model in each step of the multiscale inversion. The main difference compared to existing gradient pre-conditioners is that the variables are automatically selected based on a least squares minimization criteria of the gradient weight, which corresponds to the product of the gradient by a power of the parameter to be inverted. Based on numerical tests made with (1) a modified version of the Marmousi-2 model, and (2) a high-velocity and density local anomaly model, we illustrate that the value of the power helps to balance the gradient throughout the model. In addition, we show that a particular value exists for each parameter that optimizes the inversion results in terms of accuracy and efficiency. For the two models, the optimal power is \~{}2.0-2.5 and and \~{}1.5 for the first and second Lam{\'e} parameters, respectively; and between 3 and 6, depending on the inverted frequency, for density. These power values provide the fastest and most accurate inversion results for the three parameters in the framework of multiscale and multishooting FWI using three different optimization schemes. {\textcopyright} The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society.},
	keywords = {Computational seismology, Inverse theory, Numerical approximations and analysis, Seismic tomography},
	issn = {0956-540X},
	doi = {10.1093/gji/ggu175},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84903949166\&partnerID=tZOtx3y1},
	author = {Dagnino, D. and Sallar{\`e}s, V. and Ranero, C. R.}
}
@article {Prada2014,
	title = {{Seismic structure of the Central Tyrrhenian basin: Geophysical constraints on the nature of the main crustal domains}},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {1},
	year = {2014},
	pages = {52{\textendash}70},
	publisher = {Blackwell Publishing Ltd},
	abstract = {In this work we investigate the crustal and tectonic structures of the Central Tyrrhenian back-arc basin combining refraction and wide-angle reflection seismic (WAS), gravity, and multichannel seismic (MCS) reflection data, acquired during the MEDOC (MEDiterr{\'a}neo OCcidental)-2010 survey along a transect crossing the entire basin from Sardinia to Campania at 40{\textdegree}N. The results presented include a \~{}450 km long 2-D P wave velocity model, obtained by the traveltime inversion of the WAS data, a coincident density model, and a MCS poststack time-migrated profile. We interpret three basement domains with different petrological affinity along the transect based on the comparison of velocity and velocity-derived density models with existing compilations for continental crust, oceanic crust, and exhumed mantle. The first domain includes the continental crust of Sardinia and the conjugate Campania margin. In the Sardinia margin, extension has thinned the crust from \~{}20 km under the coastline to \~{}13 km \~{}60 km seaward. Similarly, the Campania margin is also affected by strong extensional deformation. The second domain, under the Cornaglia Terrace and its conjugate Campania Terrace, appears to be oceanic in nature. However, it shows differences with respect to the reference Atlantic oceanic crust and agrees with that generated in back-arc oceanic settings. The velocities-depth relationships and lack of Moho reflections in seismic records of the third domain (i.e., the Magnaghi and Vavilov basins) support a basement fundamentally made of mantle rocks. The large seamounts of the third domain (e.g., Vavilov) are underlain by 10-20 km wide, relatively low-velocity anomalies interpreted as magmatic bodies locally intruding the mantle. {\textcopyright}2013. American Geophysical Union. All Rights Reserved.},
	keywords = {back-arc crust, exhumed mantle, Rifting, traveltime tomography, Tyrrhenian basin, wide-angle seismics},
	issn = {21699313},
	doi = {10.1002/2013JB010527},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84896740908\&partnerID=tZOtx3y1},
	author = {Prada, M. and Sallar{\`e}s, V. and Ranero, C. R. and Vendrell, M. G. and Grevemeyer, I. and Zitellini, N. and de Franco, R.}
}
@article {Buffett2010,
	title = {{Stochastic heterogeneity mapping around a mediterranean salt lens}},
	journal = {Ocean Science},
	volume = {6},
	number = {1},
	year = {2010},
	pages = {423{\textendash}429},
	abstract = {We present the first application of Stochastic Heterogeneity Mapping based on the band-limited von K{\'a}rm{\'a}n function to a seismic reflection stack of a Mediterranean water eddy (meddy), a large salt lens of Mediterranean water. This process extracts two stochastic parameters directly from the reflectivity field of the seismic data: the Hurst number, which ranges from 0 to 1, and the correlation length (scale length). Lower Hurst numbers represent a richer range of high wavenumbers and correspond to a broader range of heterogeneity in reflection events. The Hurst number estimate for the top of the meddy (0.39) compares well with recent theoretical work, which required values between 0.25 and 0.5 to model internal wave surfaces in open ocean conditions based on simulating a Garrett-Munk spectrum (GM76) slope of \&-2. The scale lengths obtained do not fit as well to seismic reflection events as those used in other studies to model internal waves. We suggest two explanations for this discrepancy: (1) due to the fact that the stochastic parameters are derived from the reflectivity field rather than the impedance field the estimated scale lengths may be underestimated, as has been reported; and (2) because the meddy seismic image is a two-dimensional slice of a complex and dynamic three-dimensional object, the derived scale lengths are biased to the direction of flow. Nonetheless, varying stochastic parameters, which correspond to different spectral slopes in the Garrett-Munk spectrum (horizontal wavenumber spectrum), can provide an estimate of different internal wave scales from seismic data alone. We hence introduce Stochastic Heterogeneity Mapping as a novel tool in physical oceanography.},
	issn = {18120784},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77950468840\&partnerID=tZOtx3y1},
	author = {Buffett, G. G. and Hurich, C. A. and Vsemirnova, E. A. and Hobbs, R. W. and Sallar{\`e}s, V. and Carbonell, R. and Klaeschen, D. and Biescas, B.}
}
@article {Buffett2009,
	title = {{Seismic reflection along the path of the Mediterranean Undercurrent}},
	journal = {Continental Shelf Research},
	volume = {29},
	number = {15},
	year = {2009},
	month = {aug},
	pages = {1848{\textendash}1860},
	abstract = {Seismic reflection profiling is applied to the study of large scale physical oceanographic processes in the Gulf of C{\'a}diz and western Iberian coast, coinciding with the path of the Mediterranean Undercurrent. The multi-channel seismic reflection method provides clear images of thermohaline fine structure with a horizontal resolution approximately two orders of magnitude higher than CTD casting. The seismic data are compared with co-located historical oceanographic data. Three seismic reflectivity zones are identified: North Atlantic Central Water, Mediterranean Water and North Atlantic Deep Water. Seismic evidence for the path of the Mediterranean Undercurrent is found in the near-slope reflectivity patterns, with rising reflectors between about 500 and 1500 m. However, the core of the undercurrent is largely transparent. Seismic images show that central and, particularly, intermediate Mediterranean Waters have fine structure coherent over horizontal distances of several tens of kilometers. However, the intensity of the reflectors, and their horizontal coherence, decreases downstream. This change in seismic reflectivity is probably the result of diminished vertical thermohaline contrasts between adjacent water masses, so that double-diffusion processes become unable to sustain temperature and salinity staircases. Comparison of root-mean-square seismic amplitudes with temperature and salinity differences between the Mediterranean Undercurrent and the overlying central waters suggests a causal relationship between observed thermohaline fine structure and true seismic amplitudes. We estimate that, within this intermediate water stratum, impedance contrasts are mainly controlled by sound speed contrasts (a factor between 3.5 and 10 times larger than density contrasts), which are mainly controlled by temperature contrasts (a factor between 1.5 and 5 times larger than salinity contrasts). {\textcopyright} 2009 Elsevier Ltd. All rights reserved.},
	keywords = {Amplitude, Entrainment, Mediterranean Undercurrent, Mixing, Salinity, Seismic oceanography, Temperature, thermohaline fine structure},
	issn = {02784343},
	doi = {10.1016/j.csr.2009.05.017},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-69249209739\&partnerID=tZOtx3y1},
	author = {Buffett, G.G. and Biescas, B. and Pelegr{\'\i}, J.L. and Mach{\'\i}n, F. and Sallar{\`e}s, V. and Carbonell, R. and Klaeschen, D. and Hobbs, R.}
}
