Buffett, Grant; Biescas, Berta; Pelegrí, Josep Lluís; Machín, Francisco; Sallarès, Valentí; Carbonell, Ramón; Klaeschen, Dirk; Hobbs, Richard W.
13 pages, 10 figures, 4 tables.-- Printed version published Aug 20, 2009.
Giralt, Santiago; Rico, María Teresa; Vega, J. C.; Valero-Garcés, Blas L.
16 páginas, 11 figuras, 1 tabla.-- Fecha de publicación online.
Anadón, Pere; Utrilla, Rosa; Vázquez, Antonio; Martín-Rubio, M.; Rodríguez-Lázaro, Julio; Robles, F.
Stable isotopes and trace-element content of calcite ostracod valves and aragonite mollusc shells from the Pliocene lacustrine succession of Villarroya allow depicting the geochemical record of environmental changes and to compare our data to the paleoenvironmental reconstruction obtained from other proxies. The lower sequences (A and B) are characterized by relatively high isotopic and Me/Ca values in the biogenic carbonates. The recorded large variations of δ18O in these carbonates mainly reflect variations in the δ18Ow due to precipitation–evaporation processes and, to a lesser extent, variations in temperature of calcification. The δ13C data inform about changes in DIC although they are...
Sáez, Alberto; Giralt, Santiago; Hernández, Armand; Bao, Roberto; Pueyo Mur, Juan José; Moreno Caballud, Ana; Valero-Garcés, Blas L.
Gottsmann, Joachim; Wooller, Luke K.; Martí Molist, Joan; Fernández Torres, José; Camacho, Antonio G.; González Méndez, Pablo José; García García, Alicia; Rymer, Hazel
Geophysical signals accompanying the reactivation of
a volcano after a period of quiescence must be evaluated as
potential precursors to impending eruption. Here we report
on the reactivation of the central volcanic complex of
Tenerife, Spain, in spring 2004 and present gravity change
maps constructed by time-lapse microgravity measurements
taken between May 2004 and July 2005. The gravity
changes indicate that the recent reactivation after almost a
century of inactivity was accompanied by a sub-surface
mass addition, yet we did not detect widespread surface
deformation. We find that the causative source was evolving
in space and time and infer fluid migration at depth as
the most likely cause for mass increase. Our...
Gaite, Beatriz; Villaseñor, Antonio; Iglesias, Arturo; Herraiz Sarachaga, Miguel; Jimenez-Munt, Ivone
© 2015 Solid Earth. We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of the NAM plate. A new imaged feature is the low crustal velocities along the...
We present a new coherence functional to evaluate quantitatively the goodness of waveform fit between two time series as function of lag time. The proposed coherence measure is called phase cross-correlation (PCC) because it is based on the similarity of instantaneous phases. No amplitudes are explicitly involved, and PCC is therefore an amplitude unbiased measure, which equally weights every sample in the correlation window. As consequence PCC enables to discriminate between closely similar waveforms and is suited to detect weak arrivals that are concealed in larger amplitude signals. Besides, for signal recognition PCC can be applied for arrival time picking,...
11 pages, 12 figures.-- Published in: Zahn, R., Comas, M.C., and Klaus, A. (Eds), Proc. ODP, Sci. Results, 161, 345-355. College Station, TX (Ocean Drilling Program, USA).
Estrada, Ferran; Ercilla, Gemma; Gorini, Christian; Alonso, Belén; Vázquez, J. T.; García-Castellanos, Daniel; Juan, Carmen; Maldonado, Andrés; Ammar, Abdellah; Elabbassi, Mohammed
16 pages, 8 figures
Estrada, Ferran; Ercilla, Gemma; García-Castellanos, Daniel; Gorini, Christian; Alonso, Belén; Juan, Carmen; Ammar, Abdellah; Elabbassi, Mohammed
4 pages, 2 figures.
Jimenez-Munt, Ivone; Fernandez, Manel; García-Castellanos, Daniel
We study the effects of incorporating surface mass transport and the gravitational potential energy of both crust and lithospheric mantle to the viscous thin sheet approach. Recent 2D (cross-section) numerical models show that surface erosion and sediment transport can play a major role in shaping the large-scale deformation of the crust. In order to study these effects in 3D (planform view), we develop a numerical model in which both the dynamics of lithospheric deformation and surface processes are fully coupled. Deformation is calculated as a thin viscous layer with a vertically-averaged rheology and subjected to plane stresses. The coupled system...
Biescas, Berta; Sallarès, Valentí; Pelegrí, Josep Lluís; Machín, Francisco; Carbonell, Ramón; Buffett, Grant; Dañobeitia, Juan José; Calahorrano, Alcinoe
5 pages, 3 figures, 1 table.-- Supporting information http://onlinelibrary.wiley.com/doi/10.1029/2008GL033971/suppinfo
Folch, A.; Fernández Torres, José; Rundle, J. B.; Martí Molist, Joan
We obtain and compare analytical and numerical solutions for ground displacement caused by an overpressurized magma chamber placed in a linear viscoelastic medium composed of a layer over a half-space. Different parameters such as size, depth and shape of the chamber, crustal rheology and topography are considered and discussed. Numerical solutions for an axisymmetric extended source are computed using a finite element method (FEM). Analytical solutions for a point source are obtained using the dislocation theory and the propagator matrix technique. In both cases, the elastic solutions are used together with the correspondence principle of linear viscoelasticity to obtain the...
Morellón, Mario; Anselmetti, Flavio; Valero-Garcés, Blas L.; Giralt, Santiago; Ariztegui, Daniel; Sáez, Alberto; Mata, M. Pilar; Barreiro-Lostres, Fernando; Rico, María Teresa; Moreno Caballud, Ana
Banyoles (42°08'N, 2°45'E) is the largest and deepest lake of karstic-tectonic origin in the Iberian Peninsula. The lake comprises two basins and six sub-circularly shaped sub-basins fed by subaquatic springs. Periods of intense groundwater inflow in the deepest sub-basins lead to the fluidization and re-suspension of previously deposited sediments and subsequent settling forming homogenite deposits on the southern basin intermediate platforms. The multiproxy analysis of sediment cores combined with high resolution seismic stratigraphy (3.5kHz pinger and multi-frequency Chirp surveys) allows a precise reconstruction of depositional environments and related hydrological variability and groundwater inflow during the last ca. 7.6cal kyr BP....
Zhang, X.; Brown, Dennis; Deng, Y.F.
The Bangong-Nujiang suture (BNS) belt separates the Lhasa and Qiangtang plates and, as indicated from previous teleseismic tomography, receiver functions, and active source seismic experiments, record the convergence and collision between the Indian and Eurasian plates. In this study, we construct a crustal composition model along the 400 km long NNW-SSE-oriented INDEPTH III profile by comparing the P-wave velocity (V(P)), S-wave velocity (V(S)), V(P)/V(S) ratio, density (rho) and Lame impedances (rho lambda, rho mu) to those determined by laboratory measurements of different crustal rock types. Corrections for pressure and temperature are performed in order to directly compare the physical properties...
Corella, Juan Pablo; Moreno, A.; Morellón, Mario; Rull, Valentí; Giralt, Santiago; Rico, María Teresa; Pérez-Sanz, Ana; Valero-Garcés, Blas L.
Sedimentological, mineralogical and compositional analyses performed on short gravity cores and long Kullenberg cores from meromictic MontcortSs Lake (Pre-Pyrenean Range, NE Spain) reveal large depositional changes during the last 6,000 cal years. The limnological characteristics of this karstic lake, including its meromictic nature, relatively high surface area/depth ratio (surface area similar to 0.1 km(2); z (max) = 30 m), and steep margins, facilitated deposition and preservation of finely laminated facies, punctuated by clastic layers corresponding to turbidite events. The robust age model is based on 17 AMS (14)C dates. Slope instability caused large gravitational deposits during the middle Holocene, prior...
Storchak, Dmitry A.; Di Giacomo, Domenico; Engdahl, E. R.; Harris, James; Bondár, I.; Lee, William H. K.; Bormann, P.; Villaseñor, Antonio
In this introductory article we give a general description of the ISC-GEM Global Instrumental Earthquake Catalogue (1900–2009). We also provide the background for four further articles that describe the effort in collecting and digitizing parametric earthquake bulletin data as well as the methodologies developed to compute homogeneous earthquake parameters.
The result of the two and a half year project is a catalogue of approximately 20,000 large earthquakes covering 110 years with hypocentres and uncertainties computed using the same technique and velocity model. We show that the overall homogeneity of the main earthquake parameters in the catalogue was achieved despite changes in...
Macquet, M; Paul, A.; Pedersen, H.A; Villaseñor, Antonio; Chevrot, S.; Sylvander, Matthieu; Wolyniec, D.
The lithospheric architecture of the Pyrenees is still uncertain and highly debated. Here, we provide new constraints from a high-resolution 3-D S-wave velocity model of the Pyrenees and the adjacent foreland basins. This model is obtained from ambient noise tomography on records of temporary and permanent seismic arrays installed in southwestern France and northern Spain. We first computed group velocity maps for Rayleigh waves in the 5 to 55 s period range using noise correlation stacks at 1500-8500 station pairs. As the crust is very heterogeneous, poor results were obtained using a single starting model in a linearized inversion of...
Bonnin, Mickaël; Nolet, G.; Villaseñor, Antonio; Gallart Muset, Josep; Thomas, Christine
During the Cenozoic, the geodynamics of the western Mediterranean domain has been characterized by a complex history of subduction of Mesozoic oceanic lithosphere. The final stage of these processes is proposed to have led to the development of the Calabria and Gibraltar arcs, whose formation is still under debate. In this study, we take advantage of the dense broad-band station networks now available in the Alborán Sea region, to develop a high-resolution 3-D tomographic P velocity model of the upper mantle beneath the African/Iberian collision zone that will better constraint the past dynamics of this zone. The model is based...
Wu, F.T.; Liang, Wentzong; Lee, J.-C.; Benz, H.M.; Villaseñor, Antonio
The NW moving Philippine Sea plate (PSP) collides with the Eurasian plate (EUP) in the vicinity of Taiwan, and at the same time, it subducts toward the north along SW Ryukyu. The Ryukyu subduction zone terminates against eastern Taiwan. While the Ryukyu Trench is a linear bathymetric low about 100 km east of Taiwan, closer to Taiwan, it cannot be clearly identified bathymetrically owing to the deformation related to the collision, making the location of the intersection of the Ryukyu with Taiwan difficult to decipher. We propose a model for this complex of boundaries on the basis of seismicity and...