Seismic microzoning of Arica and Iquique,Chile     

Alix Becerra  Luis Podestá  Roberto Monetta  Esteban Sáez  Felipe Leyton  Gonzalo Yañez 《Natural Hazards》2015,79(1):567-586

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Geological risk assessment by a fracture measurement procedure in an urban area of Zacatecas,Mexico     

Muro-Ortega  Jesús Alejandro  de Jesús Escalona-Alcázar  Felipe  Bluhm-Gutiérrez  Jorge  Pineda-Martínez  Luis F.  Rodríguez-González  Baudelio  Valle-Rodríguez  Santiago  Reveles-Flores  Sayde María Teresa 《Natural Hazards》2022,110(3):1443-1467

Natural Hazards - Geological hazards represent medium- and long-term risks, when they affect urban infrastructure and residential areas as they become a source of danger for the population. In...  相似文献   

Updating Local Anisotropies with Template Matching During Geostatistical Seismic Inversion     

Pereira  Ângela  Azevedo  Leonardo  Soares  Amílcar 《Mathematical Geosciences》2023,55(4):497-519

Mathematical Geosciences - Iterative geostatistical seismic inversion methods are widely used to predict petro-elastic rock properties from seismic reflection data. When the model perturbation...  相似文献   

Computational models of community resilience     

Melendez  Amanda  Caballero-Russi  David  Gutierrez Soto  Mariantonieta  Giraldo  Luis Felipe 《Natural Hazards》2022,111(2):1121-1152

Natural Hazards - Protecting civil infrastructure from natural and man-made hazards is vital. Understanding the impact of these hazards helps allocate resources efficiently. Researchers have...  相似文献   

Central Mediterranean tephrochronology between 313 and 366 ka: New insights from the Fucino palaeolake sediment succession     

Niklas Leicher  Biagio Giaccio  Alison Pereira  Sebastien Nomade  Lorenzo Monaco  Giorgio Mannella  Paolo Galli  Edoardo Peronance  Danilo Mauro Palladino  Gianluca Sottili  Giovanni Zanchetta  Bernd Wagner 《Boreas: An International Journal of Quaternary Research》2023,52(2):240-271

Thirty-two tephra layers were identified in the time-interval 313–366 ka (Marine Isotope Stages 9–10) of the Quaternary lacustrine succession of the Fucino Basin, central Italy. Twenty-seven of these tephra layers yielded suitable geochemical material to explore their volcanic origins. Investigations also included the acquisition of geochemical data of some relevant, chronologically compatible proximal units from Italian volcanoes. The record contains tephra from some well-known eruptions and eruptive sequences of Roman and Roccamonfina volcanoes, such as the Magliano Romano Plinian Fall, the Orvieto–Bagnoregio Ignimbrite, the Lower White Trachytic Tuff and the Brown Leucitic Tuff. In addition, the record documents eruptions currently undescribed in proximal (i.e. near-vent) sections, suggesting a more complex history of the major eruptions of the Colli Albani, Sabatini, Vulsini and Roccamonfina volcanoes between 313 and 366 ka. Six of the investigated tephra layers were directly dated by single-crystal-fusion ⁴⁰Ar/³⁹Ar dating, providing the basis for a Bayesian age–depth model and a reassessment of the chronologies for both already known and dated eruptive units and for so far undated eruptions. The results provide a significant contribution for improving knowledge on the peri-Tyrrhenian explosive activity as well as for extending the Mediterranean tephrostratigraphical framework, which was previously based on limited proximal and distal archives for that time interval.  相似文献   

The multistage crystallization of zircon in calc-alkaline granitoids: U–Pb age constraints on the timing of Variscan tectonic activity in SW Iberia     

M. F. Pereira  M. Chichorro  P. Moita  J. F. Santos  A. M. R. Solá  I. S. Williams  J. B. Silva  R. A. Armstrong 《International Journal of Earth Sciences》2015,104(5):1167-1183

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A Bayesian framework for the validation of models for subsurface flows: synthetic experiments     

M. Akbarabadi  M. Borges  A. Jan  F. Pereira  M. Piri 《Computational Geosciences》2015,19(6):1231-1250

We present a new Bayesian framework for the validation of models for subsurface flows. We use a compositional model to simulate CO₂ storage in saline aquifers, comparing simulated saturations to observed saturations, together with a Bayesian analysis, to refine the permeability field. At the laboratory scale, we consider a core that is initially fully saturated with brine in a drainage experiment performed at aquifer conditions. Two types of data are incorporated in the framework: the porosity field in the entire core and CO₂ saturation values at equally spaced core slices for several values of time. These parameters are directly measured with a computed tomography scanner. We then find permeability fields that (1) are consistent with the measured parameters and, at the same time, (2) allow one to predict future fluid flow. We combine high performance computing, Bayesian inference, and a Markov chain Monte Carlo (McMC) method for characterizing the posterior distribution of the permeability field conditioned on the available dynamic measurements (saturation values at slices). We assess the quality of our characterization procedure by Monte Carlo predictive simulations, using permeability fields sampled from the posterior distribution. In our characterization step, we solve a compositional two-phase flow model for each permeability proposal and compare the solution of the model with the measured data. To establish the feasibility of the proposed framework, we present computational experiments involving a synthetic permeability field known in detail. The experiments show that the framework captures almost all the information about the heterogeneity of the permeability field of the core. We then apply the framework to real cores, using data measured in the laboratory.  相似文献   

An approach to the radiometric aerotriangulation of photogrammetric images     

David Hernández López  Beatriz Felipe García  José González Piqueras  Guillermo Villa Alcázar 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(6):883-893

Harnessing the radiometric information provided by photogrammetric flights could be useful in increasing the thematic applications of aerial images. The aim of this paper is to improve relative and absolute homogenization in aerial images by applying atmospheric correction and treatment of bidirectional effects. We propose combining remote sensing methodologies based on radiative transfer models and photogrammetry models, taking into account the three-dimensional geometry of the images (external orientation and Digital Elevation Model). The photogrammetric flight was done with a Z/I Digital Mapping Camera (DMC) with a Ground Sample Distance (GSD) of 45 cm. Spectral field data were acquired by defining radiometric control points in order to apply atmospheric correction models, obtaining calibration parameters from the camera and surface reflectance images. Kernel-driven models were applied to correct the anisotropy caused by the bidirectional reflectance distribution function (BRDF) of surfaces viewed under large observation angles with constant illumination, using the overlapping area between images and the establishment of radiometric tie points. Two case studies were used: 8-bit images with applied Lookup Tables (LUTs) resulting from the conventional photogrammetric workflow for BRDF studies and original 12-bit images (Low Resolution Color, LRC) for the correction of atmospheric and bidirectional effects. The proposed methodology shows promising results in the different phases of the process. The geometric kernel that shows the best performance is the Lidense kernel. The homogenization factor in 8-bit images ranged from 6% to 25% relative to the range of digital numbers (0–255), and from 18% to 35% relative to levels of reflectance (0–100) in the 12-bit images, representing a relative improvement of approximately 1–30%, depending on the band analyzed.  相似文献   

Contribution to characterisation of biochar to estimate the labile fraction of carbon   总被引：6，自引：0，他引：6  

R. Calvelo Pereira  J. KaalM. Camps Arbestain  R. Pardo LorenzoW. Aitkenhead  M. HedleyF. Macías  J. HindmarshJ.A. Maciá-Agulló 《Organic Geochemistry》2011,42(11):1331-1342

Different analytical techniques were used to find the most reliable and economic method for determining the labile fraction of C in biochar. Biochar was produced from pine, poplar and willow (PI, PO and WI, respectively) at two temperatures (400 and 550 °C) and characterised using spectroscopic techniques [solid state ¹³C nuclear magnetic resonance spectroscopy (NMR)], molecular markers [pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS)], thermogravimetry (TG), elemental composition and wet oxidation (potassium permanganate and potassium dichromate). Short term incubation (110 h) of an A horizon from an Umbrisol amended with the biochar samples at two doses (7.5 and 15 t ha⁻¹) was also carried out to provide supplementary information on the influence of biochar-soil interaction on CO₂ evolution. Spectroscopic analysis demonstrated that the degree of biochar carbonisation was influenced by the type of feedstock and heating conditions and followed the order WI-400 < PI-400 ∼ WI-550 ∼ PO-400 < PO-550 < PI-550. The thermo-labile fraction of the biochar samples, estimated from TG, ranged between 21% and 49%. The fraction of total C oxidised with potassium permanganate (C_per/C_total) was <50 g kg⁻¹ in all cases, whereas potassium dichromate (C_dichro/C_total) oxidation efficiency ranged between 180 and 545 g kg⁻¹. For each type of feedstock, the highest values of either chemically or thermally degradable C corresponded to the biochar produced at low temperature. Results indicate that low cost methodologies, such as dichromate oxidation and TG, reflected the degree of biochar carbonisation, and could therefore be used to estimate the labile fraction of C in biochar.  相似文献   

Anthropogenic heat in the city of S?o Paulo, Brazil     

Mauricio Jonas Ferreira  Amauri Pereira de Oliveira  Jacyra Soares 《Theoretical and Applied Climatology》2011,104(1-2):43-56

The main goal of this work is to describe the anthropogenic energy flux (Q _F) in the city of S?o Paulo, Brazil. The hourly, monthly, and annual values of the anthropogenic energy flux are estimated using the inventory method, and the contributions of vehicular, stationary, and human metabolism sources from 2004 to 2007 are considered. The vehicular and stationary sources are evaluated using the primary consumption of energy based on fossil fuel, bio fuel, and electricity usage by the population. The diurnal evolution of the anthropogenic energy flux shows three relative maxima, with the largest maxima occurring early in the morning (??19.9 Wm^?2) and in the late afternoon (??20.3 Wm^?2). The relative maximum that occurs around noontime (??19.6 Wm^?2) reflects the diurnal pattern of vehicle traffic that seems to be specific to S?o Paulo. With respect to diurnal evolution, the energy flux released by vehicular sources (Q _FV) contributes approximately 50% of the total anthropogenic energy flux. Stationary sources (Q _FS) and human metabolism (Q _FM) represent about 41% and 9% of the anthropogenic energy flux, respectively. For 2007, the monthly values of Q _FV, Q _FS, Q _FM, and Q _F are, respectively, 16.8?±?0.25, 14.3?±?0.16, 3.5?±?0.03, and 34.6?±?0.41?MJ?m^?2?month^?1. The seasonal evolution monthly values of Q _FV, Q _FS, Q _FM, and Q _F show a relative minimum during the summer and winter vacations and a systematic and progressive increase associated with the seasonal evolution of the economic activity in S?o Paulo. The annual evolution of Q _F indicates that the city of S?o Paulo released 355.2?MJ?m^?2?year^?1 in 2004 and 415.5?MJ?m^?2?year^?1 in 2007 in association with an annual rate of increase of 19.6?MJ?m^?2?year^?1 (from 2004 to 2006) and 30.5?MJ?m^?2?year^?1 (from 2006 to 2007). The anthropogenic energy flux corresponds to about 9% of the net radiation at the surface in the summer and 15% in the winter. The amplitude of seasonal variation of the maximum hourly value of the diurnal variation increases exponentially with latitude.  相似文献