@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 {Palomeras2009,
	title = {{Nature of the lithosphere across the Variscan orogen of SW Iberia: Dense wide-angle seismic reflection data}},
	journal = {Journal of Geophysical Research},
	volume = {114},
	number = {B2},
	year = {2009},
	month = {feb},
	pages = {B02302},
	abstract = {Two wide-angle seismic transects have been acquired across the SW Iberian Massif. They crossed three major geological zones (South Portuguese Zone, Ossa-Morena Zone, and Central Iberian Zone), with their tectonic contacts and the Pyrite Belt being of greatest interest. A total of 690 digital seismic recording instruments (650 Texans and 40 Reftek 3 component units) from the IRIS-PASSCAL Instrument Pool were used. The transects (A and B) are each approximately 300 km long and consist of 3 and 6 shot points, respectively, with an approximately 60-km shot point interval. The charge sizes range from 1000 kg at the edges to 500 kg at the center. These recently acquired experiments were designed to provide velocity constraints on the lithosphere and to complement the previously acquired normal incidence seismic profile IBERSEIS. Both data sets are part of the SW Iberia project, which was developed within the EUROPROBE program and designed to address fundamental questions about the nature and dynamics of the Variscan lithosphere. The acquisition parameters provide closely spaced wide-angle seismic images of the lithosphere beneath SW Iberia. In transect A, the station spacing was on average 400 m, while along transect B, the receiver spacing was approximately 150 m. Because of this close trace spacing, the lateral continuity of the seismic arrivals is greatly improved. Frequency analysis revealed that the recorded events feature relatively low frequencies (6-25 Hz). After processing, the shot records show high-amplitude and well-defined arrivals. The interpreted PmP arrival, located at approximately 11 s (normal incidence traveltime), is characterized by high amplitude and relatively low frequency (6-12 Hz). A well-defined Pn arrival appears at offsets beyond 120 km. At far offsets greater than 180 km, an upper mantle reflection is observed. Furthermore, within the upper crust, the shots records feature a relatively high-velocity arrival, located at 4-5-s normal incidence traveltime. The analysis of this arrival indicates that it probably corresponds to the top of the Iberian Reflective Body identified in the IBERSEIS deep seismic profile. The velocity models obtained by forward modeling show a complex crust, especially in the middle crust. The velocity models are the most detailed ones that have been produced in the area and contain a large amount of new features that are relevant to the understanding of the composition of the crust and upper mantle beneath the zone. The velocity depth functions derived from the velocity models have higher middle crustal velocities than the average in other continental areas. A comparison between laboratory seismic velocity measurements and the velocities of the models was carried out in order to estimate the crustal and the upper mantle composition. Results indicate that the high middle crust velocities correspond to rocks of a mafic composition. The combined data set reveals new aspects related to the lithospheric evolution of this transpressive orogen and allows us to attempt an interpretative cross section of the upper lithosphere in SW Iberia. {\textcopyright} 2009.},
	issn = {0148-0227},
	doi = {10.1029/2007JB005050},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-66149180585\&partnerID=tZOtx3y1},
	author = {Palomeras, I. and Carbonell, R. and Flecha, I. and Simancas, F. and Ayarza, P. and Matas, J. and Mart{\'\i}nez Poyatos, D. and Azor, A. and Gonz{\'a}lez Lodeiro, F. and P{\'e}rez-Esta{\'u}n, A.}
}
@article {Sallares2009,
	title = {{Relative contribution of temperature and salinity to ocean acoustic reflectivity}},
	journal = {Geophysical Research Letters},
	volume = {36},
	number = {20},
	year = {2009},
	month = {oct},
	pages = {L00D06},
	abstract = {Marine seismic data display laterally coherent reflectivity from the water column that is attributed to fine-scale oceanic layering. The amplitude of the different reflections is the expression of acoustic impedance contrasts. between neighbouring water masses, and therefore water reflectivity maps the ocean{\textquoteright}s vertical sound speed and density (i.e., temperature and salinity) variations. Here we determine the relative contribution of each parameter by computing the temperature and salinity partial derivatives of sound speed and density, and using them to estimate reflection coefficients from a real oceanographic dataset. The results show that the mean contribution of density variations is 5-10\%, while 90-95\% is due to sound speed variations. On average, 80\% of reflectivity comes from temperature contrasts. Salinity contribution averages 20\%, but it is highly variable and reaches up to 40\% in regions prone to diffusive convection such as the top of the Mediterranean Undercurrent in the Gulf of Cadiz. Copyright 2009 by the American Geophysical Union.},
	issn = {0094-8276},
	doi = {10.1029/2009GL040187},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-72149084920\&partnerID=tZOtx3y1},
	author = {Sallar{\`e}s, V. and Biescas, B. and Buffett, G. and Carbonell, R. and Danobeitia, J. J. and Pelegr{\'\i}, J. L.}
}
@article {Flecha2009,
	title = {{Seismic imaging and modelling of the lithosphere of SW-Iberia}},
	journal = {Tectonophysics},
	volume = {472},
	number = {1-4},
	year = {2009},
	month = {jul},
	pages = {148{\textendash}157},
	abstract = {Data from a closely spaced wide-angle transect has been used to study the middle-to-lower crust and the Moho in SW-Iberia. A low-fold wide-angle stack image reveals a highly heterogeneous seismic signature at lower-crustal levels changing laterally along the profile. The lower crust features an irregular distribution of the reflectivity that can be explained by a heterogeneous distribution of physical properties. The Moho discontinuity also features a high variability in its seismic character that correlates with the different tectonic terranes in the area. A 2D finite difference code was used for solving the elastic wave equation and to provide synthetic wide-angle shots. Relatively simple layer cake model derived from conventional refraction interpretation generates the main events of the shot records. However, these models cannot account for the lateral variability of the seismic signature. In order to obtain more realistic simulations, the velocity model was modified introducing stochastic lensing at different levels within the crust. The Moho was modelled as a 3~km thick layered structure. The resulting average velocity models include a high velocity layer at mid-crustal depth, a highly reflective lower crust and a relatively thin horizontal Moho. This heterogeneous model can be achieved by lensing within the crust, a layered mafic intrusion and a strongly laminated lower crust and Moho. {\textcopyright} 2008 Elsevier B.V. All rights reserved.},
	keywords = {Crustal heterogeneities, Mafic intrusions, Wide-angle stack},
	issn = {00401951},
	doi = {10.1016/j.tecto.2008.05.033},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-67349173557\&partnerID=tZOtx3y1},
	author = {Flecha, I. and Palomeras, I. and Carbonell, R. and Simancas, F. and Ayarza, P. and Matas, J. and Gonz{\'a}lez-Lodeiro, F. and P{\'e}rez-Esta{\'u}n, A.}
}
@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.}
}
@article {Biescas2008,
	title = {{Imaging meddy finestructure using multichannel seismic reflection data}},
	journal = {Geophysical Research Letters},
	volume = {35},
	number = {11},
	year = {2008},
	month = {jun},
	pages = {L11609},
	abstract = {This work illustrates the great potential of multichannel seismic reflection data to extract information from the finestructure of meddies with exceptional lateral resolution (10-15 m). We present seismic images of three meddies acquired in the Gulf of Cadiz (SW Iberian Peninsula), which consist of concentric reflectors forming oval shapes that sharply contrast with the background oceanic structure. The seismic images reveal the presence of different regions within the meddies that are consistent with those observed in historical temperature (T) and salinity (S) data. The core region, characterized by smooth T and S variations, is weakly reflective. The double-diffusive upper and lower boundaries and the lateral-interleaving outer edges, characterized by stronger T and S contrasts, display strong reflectivity bands. These new observations clearly show differences between layers developed at the upper and lower boundaries that can contribute to th knowledge of mixing processes and layering formation in oceans. Copyright 2008 by the American Geophysical Union.},
	issn = {0094-8276},
	doi = {10.1029/2008GL033971},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-49849096389\&partnerID=tZOtx3y1},
	author = {Biescas, B. and Sallar{\`e}s, V. and Pelegr{\'\i}, J. L. and Mach{\'\i}n, F. and Carbonell, R. and Buffett, G. and Danobeitia, J. J. and Calahorrano, A.}
}
