Dynamical parameter analysis of continuous seismic signals of Popocatépetl volcano (Central Mexico): A case of tectonic earthquakes influencing volcanic activity     

Marta Tárraga  Servando De La Cruz-Reyna  Ana T. Mendoza-Rosas  Roberto Carniel  Alicia Martínez-Bringas  Alicia García  Ramon Ortiz 《Acta Geophysica》2012,60(3):664-681

The continuous background seismic activity contains information on the internal state of a volcanic system. Here, we report the influence of major regional tectonic earthquakes (M > 5 in most cases) on such state, reflected as changes in the spectral and dynamical parameters of the volcano continuous seismic data. Although changes do not always occur, analysis of five cases of earthquake-induced variations in the signals recorded at Popocatépetl volcano in central México reveal significant fluctuations following the tectonic earthquakes. External visible volcanic activity, such as small to moderate explosions and ash emissions, were related to those fluctuations. We briefly discuss possible causes of the variations. We conclude that recognition of fluctuations in the dynamical parameters in volcano monitoring seismic signals after tectonic earthquakes, even those located in the far field, hundreds of kilometers away, may provide an additional criterion for eruption forecasting, and for decision making in the definition of volcanic alert levels.  相似文献   

Forest biodiversity assessment in Peruvian Andean Montane cloud forest     

Alicia Ledo  Sonia Condés  Iciar Alberdi 《山地科学学报》2012,9(3):372-384

Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as regards biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the "Bosque de Neblina de Cuyas", in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity.  相似文献   

Erratum to: Fuzzy Logic Determination of Lithologies from Well Log Data: Application to the KTB Project Data set (Germany)     

David Bosch  Juanjo Ledo  Pilar Queralt 《Surveys in Geophysics》2014,35(2):479-481

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A rootless suture and the loss of the roots of a mountain chain: The Variscan belt of NW Iberia     

José R. Martínez Catalán  Ricardo Arenas  Jacobo Abati  Sonia Sánchez Martínez  Florentino Díaz García  Javier Fernández Suárez  Pablo González Cuadra  Pedro Castiñeiras  Juan Gómez Barreiro  Alejandro Díez Montes  Emilio González Clavijo  Francisco J. Rubio Pascual  Pilar Andonaegui  Teresa E. Jeffries  James E. Alcock  Rubén Díez Fernández  Alicia López Carmona 《Comptes Rendus Geoscience》2009,341(2-3):114-126

Ophiolites of different Paleozoic ages occur in North-West (NW) Iberia in a rootless suture representing the remnants of the Rheic Ocean. Associated allochthonous terranes in the hanging- and foot-walls of the suture derive from the former margins, whereas the relative autochthon corresponds to the Paleozoic passive margin of northern Gondwana. The Paleozoic tectonic evolution of this part of the circum-Atlantic region is deduced from the stratigraphical, petrological, structural and metamorphic evolution of the different units and their ages. The tectonic reconstruction covers from Cambro-Ordovician continental rifting and the opening of the Rheic Ocean to its Middle to Upper Devonian closure. Then, the Variscan Laurussia–Gondwana convergence and collision is briefly described, from its onset to the late stages of collapse associated with the demise of the orogenic roots.  相似文献   

Possible interaction between tectonic events and seismic noise at Las Cañadas Volcanic Caldera,Tenerife, Spain     

Roberto Carniel  Marta Tárraga  Fausto Barazza  Alicia García 《Bulletin of Volcanology》2008,70(9):1113-1121

Continuous seismic noise is recorded in the volcanic island of Tenerife (Canary Islands, Spain). The origin of this noise, strongly augmented by anthropogenic contamination, is still under debate. In this paper, we discuss the relationship between this noise and the occurrence of local tectonic events in the same area. In particular, transitions are sought in the time evolution of dynamic parameters computed on the seismic noise, and examples are shown where abrupt transitions may be associated with the occurrence of tectonic events. These transitions provide further evidence of the existence of a natural origin for at least part of the seismic noise, which is strongly contaminated—if not dominated—by anthropogenic sources.  相似文献   

CYP1B1 knockdown does not alter synergistic developmental toxicity of polycyclic aromatic hydrocarbons in zebrafish (Danio rerio)     

Timme-Laragy AR  Noyes PD  Buhler DR  Di Giulio RT 《Marine environmental research》2008,66(1):85-87

Polycyclic aromatic hydrocarbons (PAHs) are contaminants increasing in the environment largely due to burning of fossil fuels. Our previous work identified a synergistic toxicity interaction in zebrafish embryos occurring when PAHs that are agonists for the aryl hydrocarbon receptor (AHR) co-occur with PAHs that are CYP1A inhibitors. This toxicity is mediated by the AHR2, and morpholino knockdown of CYP1A exacerbated toxicity. This study tested two hypotheses: (1) in the absence of functional CYP1A, metabolism of PAHs is shunted towards CYP1B1, which has been shown in mammals to produce more reactive metabolites of PAHs; alternatively, (2) CYP1B1 serves a protective role similar to CYP1A. We used a morpholino approach to knockdown CYP1B1 alone and in co-knockdown with CYP1A to determine whether we could alter deformities caused by synergistic toxicity of PAHs. CYP1B1 knockdown was not different from non-injected controls; nor were CYP1B1+CYP1A co-knockdown deformities different from CYP1A knockdown alone. These data suggest that CYP1B1 is not a significant factor in causing synergistic toxicity of PAHs, nor, in contrast to CYP1A, in providing protection.  相似文献   

An assessment of ancient DNA preservation in Holocene–Pleistocene fossil bone excavated from the world heritage Naracoorte Caves,South Australia          下载免费PDF全文

Alicia Grealy  Amy Macken  Morten E. Allentoft  Nicolas J. Rawlence  Elizabeth Reed  Michael Bunce 《第四纪科学杂志》2016,31(1):33-45

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Variability in plankton community structure, metabolism, and vertical carbon fluxes along an upwelling filament (Cape Juby, NW Africa)     

Javier Arístegui  Eric D. Barton  Paul Tett  María F. Montero  Mercedes García-Muoz  Gotzon Basterretxea  Anne-Sophie Cussatlegras  Alicia Ojeda  Demetrio de Armas 《Progress in Oceanography》2004,62(2-4):95

The variability in dissolved and particulate organic matter, plankton biomass, community structure and metabolism, and vertical carbon fluxes were studied at four stations (D₁–D₄), placed along a coastal-offshore gradient of an upwelling filament developed near Cape Juby (NW Africa). The filament was revealed as a complex and variable system in terms of its hydrological structure and distribution of biological properties. An offshore shift from large to small phytoplankton cells, as well as from higher to lower autotrophic biomass, was not paralleled by a similar gradient in particulate (POC) or dissolved (DOC) organic carbon. Rather, stations in the central part of the filament (D₂ and D₃) presented the highest organic matter concentrations. Autotrophic carbon (POC_Chl) accounted for 53% (onshore station, D₁) to 27% (offshore station, D₄) of total POC (assuming a carbon to chlorophyll ratio of 50), from which nano- and pico-phytoplankton biomasses (POC_{A < 10 μm}) represented 14% (D₁) to 79% (D₄) of POC_Chl. The biomass of small hetrotrophs (POC_{H < 10 μm}) was equivalent to POC_{A < 10 μm}, except at D₁, where small autotrophs were less abundant. Dark community respiration (R_d) in the euphotic zone was in general high, almost equivalent to gross production (P_g), but decreasing offshore (D₁–D₄, from 108 to 41 mmol C m⁻² d⁻¹). POC sedimentation rates (POC_sed) below the euphotic zone ranged from 17 to 6 mmol C m⁻² d⁻¹. Only at D₄ was a positive carbon balance observed: P_g−(R_d + POC_sed) = 42 mmol C m⁻² d⁻¹. Compared to other filament studies from the NE Atlantic coast, the Cape Juby filament presented lower sedimentation rates and higher respiration rates with respect to gross production. We suggest that this is caused by the recirculation of the filament water, induced by the presence of an associated cyclonic eddy, acting as a trapping mechanism for organic matter. The export capacity of the Cape Juby filament therefore would be constrained to the frequency of the interactions of the filament with island-induced eddies.  相似文献   

Reproductive ecology and abundance of the sand tiger shark, Carcharias taurus, from the southwestern Atlantic     

Lucifora  Luis O.; Menni  Roberto C.; Escalante  Alicia H. 《ICES Journal of Marine Science》2002,59(3):553-561

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North Atlantic winter eddy-driven jet and atmospheric blocking variability in the Community Earth System Model version 1 Large Ensemble simulations     

Kwon  Young-Oh  Camacho  Alicia  Martinez  Carlos  Seo  Hyodae 《Climate Dynamics》2018,51(9-10):3275-3289

Climate Dynamics - The atmospheric jet and blocking distributions, especially in the North Atlantic sector, have been challenging features for a climate model to realistically reproduce. This study...  相似文献