Deformation and Gravity Change: Indicators of Isostasy, Tectonics, Volcanism and Climate Change, Volume III. Introduction     

Detlef Wolf  Miguel Angel Santoyo  José Fernández 《Pure and Applied Geophysics》2012,169(8):1329-1330

  相似文献   

March 1, 2005 Daylight Fireball Over Galicia (NW of Spain) and Minho (N. Portugal)     

José Angel Docobo  Josep Maria Trigo-Rodríguez  Jiri Borovicka  Vakhtang S. Tamazian  Vera Assis Fernandes  Jordi Llorca 《Earth, Moon, and Planets》2008,102(1-4):537-542

A daylight bolide was observed over Galicia (NW Spain) and Minho (N. Portugal) on March 1, 2005 at 15 h10 min ± 3 min UTC. We interviewed 23 eyewitnesses of the event in order to obtain the azimuth, altitude, and slope of the fireball’s trajectory. Reports suggest an atmospheric ending height below 20 km, indicating that meteorite survival was likely. From the reconstructed trajectory and the fireball’s duration, we obtained the approximate heliocentric orbits for the meteoroid. Assuming an entry velocity higher than 20 km s⁻¹ which is consistent with its estimated duration, the meteoroid originated in the asteroid belt.  相似文献   

Assessment of soft-bottom Polychaeta assemblage affected by a spatial confluence of impacts: Sewage and brine discharges     

Del-Pilar-Ruso Yoana  De-la-Ossa-Carretero Jose Antonio  Loya-Fernández Angel  Ferrero-Vicente Luis Miguel  Giménez-Casalduero Francisca  Sánchez-Lizaso Jose Luis 《Marine pollution bulletin》2009,58(5):776-782

  相似文献   

Effects of Physical Processes and Sampling Resolution on Fault Displacement Versus Length Scaling: The Case of the Cantarell Complex Oilfield,Gulf of Mexico     

Shunshan Xu  Angel F. Nieto-Samaniego  Gustavo Murillo-Muñetón  Susana A. Alaniz-Álvarez  José M. Grajales-Nishimura  Luis G. Velasquillo-Martinez 《Pure and Applied Geophysics》2016,173(4):1125-1142

  相似文献   

Stratigraphy, chemistry, and eruptive dynamics of the 12.4 ka plinian eruption of Apoyeque volcano, Managua, Nicaragua     

Denis Ramón Avellán  José Luis Macías  Giovanni Sosa-Ceballos  Gema Velásquez 《Bulletin of Volcanology》2014,76(2):1-19

Apoyeque volcano, located 9 km northwest of Managua city, erupted explosively at 12.4 ka. The Plinian eruption deposited a widespread pumice fall deposit known as the Upper Apoyeque Tephra (UAq). The UAq is massive, reversely graded, and consists of white juvenile pumice (~78 vol.%), a variety of cognate lithics and accidental altered lithics. The whole-rock pumice composition is rhyodacitic (SiO₂?=?66.9–68.5 wt.%) with a mineral paragenesis of plagioclase, orthopyroxene, clinopyroxene, amphibole, titanomagnetite, and ilmenite in a rhyolitic glass groundmass (SiO₂?=?74.4?±?0.6 wt.%). The deposit’s dispersal axis is to the south, with the deposit covering a minimum area of 877 km² within the 50 cm isopach and has a total volume of 3 km³ (dense rock equivalent, 1.15 km³). The eruption column reached a maximum height of ca.28 km. The eruption ejected a total mass of 3?×?10¹² kg at an average rate of 2?×?10⁸ kg/s, and based on available models, we infer duration of almost 4 h. Petrographic and geochemical characteristics suggest that the eruption was triggered by magma mixing.  相似文献   

Spatial assessment of fishing effort around European marine reserves: implications for successful fisheries management   总被引：7，自引：0，他引：7  

Stelzenmüller V  Maynou F  Bernard G  Cadiou G  Camilleri M  Crec'hriou R  Criquet G  Dimech M  Esparza O  Higgins R  Lenfant P  Pérez-Ruzafa A 《Marine pollution bulletin》2008,56(12):2018-2026

We examined the spatial dynamic of artisanal fishing fleets around five European marine protected areas (MPAs) to derive general implications for the evaluation of MPAs as fisheries management tools. The coastal MPAs studied were located off France, Malta and Spain and presented a variety of spatial designs and processes of establishment. We developed a standardized methodology to define factors influencing effort allocation and to produce fishing effort maps by merging GIS with geostatistical modelling techniques. Results revealed that in most cases the factors “distance to the no-take”, “water depth”, and “distance to the port” had a significant influence on effort allocation by the fishing fleets. Overall, we found local concentration of fishing effort around the MPA borders. Thus, neglecting the pattern of fishing effort distribution in evaluating MPA benefits, such as spillover of biomass, could hamper sound interpretation of MPAs as fisheries management tools.  相似文献   

Using M-AMBI in assessing benthic quality within the Water Framework Directive: some remarks and recommendations   总被引：1，自引：1，他引：0  

Borja A  Mader J  Muxika I  Rodríguez JG  Bald J 《Marine pollution bulletin》2008,56(7):1377-1379

  相似文献   

Scale effects on modelling the seismic signature of gas: results from an outcrop analogue          下载免费PDF全文

Maria‐Daphne Mangriotis  Colin MacBeth  Angel Briceño 《Geophysical Prospecting》2018,66(6):1159-1179

Numerous examples of reservoir fields from continental and marine environments involve thin‐bedded geology, yet, the inter‐relationship between thin‐bedded geology, fluid flow and seismic wave propagation is poorly understood. In this paper, we explore the 4D seismic signature due to saturation changes of gas within thin layers, and address the challenge of identifying the relevant scales and properties, which correctly define the geology, fluid flow and seismic wave propagation in the field. Based on the study of an outcrop analogue for a thin‐bedded turbidite, we model the time‐lapse seismic response to fluid saturation changes for different levels of model scale, and explore discrepancies in quantitative seismic attributes caused by upscaling. Our model reflects the geological complexity associated with thin‐bedded turbidites, and its coupling to fluid flow, which in turn affects the gas saturation distribution in space, and its time‐lapse seismic imprint. Rock matrix and fluid properties are modelled after selected fields to reproduce representative field models with realistic impedance contrasts. In addition, seismic modelling includes multiples, in order to assess their contribution in seismic propagation through thin gas layers. Our results show that multiples could contribute significantly to the measured amplitudes in the case of thin‐bedded geology. This suggests that forward/inverse modelling involving the flow simulation and seismic domains used in time‐lapse seismic interpretation should account for thin layers, when these are present in the geological setting.  相似文献   

The frequency and distribution of recent landslides in three montane tropical regions of Puerto Rico   总被引：12，自引：0，他引：12  

Matthew C. Larsen  Angel J. Torres-Snchez 《Geomorphology》1998,24(4):309-331

Landslides are common in steep mountainous areas of Puerto Rico where mean annual rainfall and the frequency of intense storms are high. Each year, landslides cause extensive damage to property and occasionally result in loss of life. Average population density is high, 422 people/km², and is increasing. This increase in population density is accompanied by growing stress on the natural environment and physical infrastructure. As a result, human populations are more vulnerable to landslide hazards. The Blanco, Cibuco, and Coamo study areas range in surface area from 276 to 350 km² and represent the climatologic, geographic, and geologic conditions that typify Puerto Rico. Maps of recent landslides developed from 1:20,000-scale aerial photographs, in combination with a computerized geographic information system, were used to evaluate the frequency and distribution of shallow landslides in these areas. Several types of landslides were documented—rainfall-triggered debris flows, shallow soil slips, and slumps were most abundant. Hillslopes in the study area that have been anthropogenically modified, exceed 12° in gradient, are greater than 300 m in elevation, and face the east-northeast, are most prone to landsliding. A set of simplified matrices representing geographic conditions in the three study areas was developed and provides a basis for the estimation of the spatial controls on the frequency of landslides in Puerto Rico. This approach is an example of an analysis of the frequency of landslides that is computationally simple, and therefore, may be easily transferable to other settings.  相似文献   

Electron spin resonance and related studies of lignite and ball clay from South Devon,England     

Peter L. Hall  B.R. Angel  J. Braven 《Chemical Geology》1974,13(2):97-113

Electron spin resonance and infrared spectroscopic studies of lignite and ball clay from South Devon, and of extracts obtained from them by solvent fractionation, revealed similarities between corresponding organic components associated with both materials. All fractions exhibited a free radical resonance at g = 2.0037, which occurred with greatest intensity in the humic acids. Additional ESR features due to Fe³⁺, Mn²⁺ and VO²⁺ complexes were observed. Ferric ions give rise to resonances at g = 4.2 which have not been previously reported in the case of natural carbonaceous materials. It is shown that the paramagnetic species associated with the ball clay and lignite extracts do not significantly contribute to the observed ESR spectra of kaolinites, the latter being attributable to substituted Fe³⁺ ions and defect centres within the kaolinite lattice.  相似文献