The SHARE European Earthquake Catalogue (SHEEC) 1000–1899     

M. Stucchi  A. Rovida  A. A. Gomez Capera  P. Alexandre  T. Camelbeeck  M. B. Demircioglu  P. Gasperini  V. Kouskouna  R. M. W. Musson  M. Radulian  K. Sesetyan  S. Vilanova  D. Baumont  H. Bungum  D. Fäh  W. Lenhardt  K. Makropoulos  J. M. Martinez Solares  O. Scotti  M. Živčić  P. Albini  J. Batllo  C. Papaioannou  R. Tatevossian  M. Locati  C. Meletti  D. Viganò  D. Giardini 《Journal of Seismology》2013,17(2):523-544

In the frame of the European Commission project “Seismic Hazard Harmonization in Europe” (SHARE), aiming at harmonizing seismic hazard at a European scale, the compilation of a homogeneous, European parametric earthquake catalogue was planned. The goal was to be achieved by considering the most updated historical dataset and assessing homogenous magnitudes, with support from several institutions. This paper describes the SHARE European Earthquake Catalogue (SHEEC), which covers the time window 1000–1899. It strongly relies on the experience of the European Commission project “Network of Research Infrastructures for European Seismology” (NERIES), a module of which was dedicated to create the European “Archive of Historical Earthquake Data” (AHEAD) and to establish methodologies to homogenously derive earthquake parameters from macroseismic data. AHEAD has supplied the final earthquake list, obtained after sorting duplications out and eliminating many fake events; in addition, it supplied the most updated historical dataset. Macroseismic data points (MDPs) provided by AHEAD have been processed with updated, repeatable procedures, regionally calibrated against a set of recent, instrumental earthquakes, to obtain earthquake parameters. From the same data, a set of epicentral intensity-to-magnitude relations has been derived, with the aim of providing another set of homogeneous Mw estimates. Then, a strategy focussed on maximizing the homogeneity of the final epicentral location and Mw, has been adopted. Special care has been devoted also to supply location and Mw uncertainty. The paper focuses on the procedure adopted for the compilation of SHEEC and briefly comments on the achieved results.  相似文献   

Modeling the Permeability Loss of Metallic Iron Water Filtration Systems     

Sabine Caré  Richard Crane  Paolo S. Calabrò  Antoine Ghauch  Emile Temgoua  Chicgoua Noubactep 《洁净——土壤、空气、水》2013,41(3):275-282

Over the past 30 years the literature has burgeoned with in situ approaches for groundwater remediation. Of the methods currently available, the use of metallic iron (Fe⁰) in permeable reactive barrier (PRB) systems is one of the most commonly applied. Despite such interest, an increasing amount of experimental and field observations have reported inconsistent Fe⁰ barrier operation compared to contemporary theory. In the current work, a critical review of the physical chemistry of aqueous Fe⁰ corrosion in porous media is presented. Subsequent implications for the design of Fe⁰ filtration systems are modeled. The results suggest that: (i) for the pH range of natural waters (>4.5), the high volumetric expansion of Fe⁰ during oxidation and precipitation dictates that Fe⁰ should be mixed with a non‐expansive material; (ii) naturally occurring solute precipitates have a negligible impact on permeability loss compared to Fe⁰ expansive corrosion; and (iii) the proliferation of H₂ metabolizing bacteria may contribute to alleviate permeability loss. As a consequence, it is suggested that more emphasis must be placed on future work with regard to considering the Fe⁰ PRB system as a physical (size‐exclusion) water filter device.  相似文献   

Volcanic ash detection by GPS signal     

Massimo Aranzulla  Flavio Cannavò  Simona Scollo  Giuseppe Puglisi  Giuseppina Immè 《GPS Solutions》2013,17(4):485-497

We investigate the ability of GPS to detect volcanic plumes at Mt. Etna, Italy. We use a robust statistical approach to highlight whether the presence of a volcanic plume in the atmosphere may really affect the GPS undifferenced post-fit phase residuals. The proposed method has been tested for the September 4–5, 2007 activity of Mt. Etna. This eruption produced powerful lava fountains forming a weak, a few kilometers high plume for several hours, representing typical activity at Etna over the last 5 years. We analyzed data from nineteen Etna permanent GPS stations located on the volcano flanks at different heights and applied a statistical test based on four main steps: (a) realization of a simplified model representing the volcanic plume in atmosphere; (b) evaluation of the GPS satellite and station couples intersecting the plume; (c) calculation of the volcanic plume region crossed by the GPS signal; (d) application of a robust statistical test in order to see whether the volcanic plume affected the GPS signals. Results show that during the September 4–5, 2007 explosive activity, the GPS residuals definitely include the contribution of the volcanic plume. Our analysis shows that values of the GPS residuals are ten times smaller than those found for the Miyakejima eruption (Japan), highlighting a likely relationship between residuals and eruption intensity. In the future, data derived from the GPS stations located on Etna’s flanks could be used to improve the alerting system of volcanic ash, already operating at the Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo.  相似文献   

Variations of young oceanic intraplate seismic energy released with relation to lithosphere age. Implications in the East Pacific Rise and its convergence with the Rivera subduction zone     

Pinzón  Nicolás  Vargas  Carlos A. 《Marine Geophysical Researches》2019,40(4):643-654

Marine Geophysical Research - We have estimated empirical relationships that associate the age of the Pacific oceanic lithosphere with the seismic energy released on both flanks of the East Pacific...  相似文献   

A metrologic method of anomaly field amplitude bottom reduction in undersampled geomagnetic marine surveys     

Faggioni  Osvaldo  Beverini  Nicolò  Carmisciano  Cosmo  Giori  Italiano 《Marine Geophysical Researches》2001,22(2):63-79

We show the results obtained by means of a seabed reduction technique on the intensity of geomagnetic anomaly fields applied to a synthetic case and then to the real case of a geomagnetic survey of eastern Ligurian Sea (Italy). The eastern Ligurian Sea has very intense short waves anomaly fields and a sea bed that varies greatly in depth. As a result the geomagnetic space signal is characterized by a very large spectral content; in these conditions it is not possible to obtain a full sampled marine survey and vertical continuation analytic procedures and standard numerical bottom reduction based on a single vertical incremental parameter, whichever is applicable, fails to give accurate results. The present technique, which has been fine-tuned over 4 years of experimentation in environmental researchs, aims to provide a simple and efficient means to reduce the distortion of geomagnetic anomalies field caused by the variation of distance between survey plane and magnetic outcrop source position. The compensation procedure is based on evaluation, by comparison of two measurements carried out at different altitudes, of the mean vertical increment typical of each anomaly field principal frequency component bands. The component anomaly fields are then corrected by application of the corresponding vertical increments and lastly, the anomaly geomagnetic field reduced to the sea-bed is computed as Inverse Fourier Transform of a spectrum built as synthesis of the component anomaly fields' spectra. The results obtained have shown a notable increase in definition of anomaly field intensity without the production of appreciable distortions or false geomagnetic echoes. This revised version was published online in November 2006 with corrections to the Cover Date.  相似文献   

The International Subcommission on Jurassic Stratigraphy     

Nicol Morton 《Proceedings of the Geologists' Association. Geologists' Association》2008,119(1):97-103

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Linking land and sea： Towards global reconstructions of the Jurassic world     

Nicol Morton 《《幕》》2008,31(4):420-422

The Jurassic is traditionally famous for shallow marine sediments that are often very fossiliferous, notably in Europe, where the standard chronostratigraphic subdivisions were established and defined. However, widespread marginal and non-marine Jurassic sediments are also known, and are of great importance for the wellpreserved terrestrial biotas they contain, as well as for their hydrocarbon and coal reserves. IGCP Project 506 is directed towards finding means of correlation between marine and non-marine Jurassic rocks, as a foundation for a better understanding of the evolution of the Earth during the Jurassic Period.  相似文献   

On the explicit determination of stability constants for linearized geodetic boundary value problems     

Fernando Sansò  Giovanna Venuti 《Journal of Geodesy》2008,82(12):909-916

The theory of GBVPs provide the basis to the approximate methods used to compute global gravity models. A standard approximation procedure is least squares, which implicitly assumes that data, e.g. gravity disturbance and gravity anomaly, are given functions in L ²(S). We know that solutions in these cases exist, but uniqueness (and coerciveness which implies stability of the numerical solutions) is the real problem. Conditions of uniqueness for the linearized fixed boundary and Molodensky problems are studied in detail. They depend on the geometry of the boundary; however, the case of linearized fixed boundary BVP puts practically no constraint on the surface S, while the linearized Molodensky BVP requires the previous knowledge of very low harmonics, for instance up to degree 25, if we want the telluroid to be free to have inclinations up to 60^°.  相似文献   

Space-Wise approach for airborne gravity data modelling     

D. Sampietro  M. Capponi  A. H. Mansi  A. Gatti  P. Marchetti  F. Sansò 《Journal of Geodesy》2017,91(5):535-545

Regional gravity field modelling by means of remove-compute-restore procedure is nowadays widely applied in different contexts: it is the most used technique for regional gravimetric geoid determination, and it is also used in exploration geophysics to predict grids of gravity anomalies (Bouguer, free-air, isostatic, etc.), which are useful to understand and map geological structures in a specific region. Considering this last application, due to the required accuracy and resolution, airborne gravity observations are usually adopted. However, due to the relatively high acquisition velocity, presence of atmospheric turbulence, aircraft vibration, instrumental drift, etc., airborne data are usually contaminated by a very high observation error. For this reason, a proper procedure to filter the raw observations in both the low and high frequencies should be applied to recover valuable information. In this work, a software to filter and grid raw airborne observations is presented: the proposed solution consists in a combination of an along-track Wiener filter and a classical Least Squares Collocation technique. Basically, the proposed procedure is an adaptation to airborne gravimetry of the Space-Wise approach, developed by Politecnico di Milano to process data coming from the ESA satellite mission GOCE. Among the main differences with respect to the satellite application of this approach, there is the fact that, while in processing GOCE data the stochastic characteristics of the observation error can be considered a-priori well known, in airborne gravimetry, due to the complex environment in which the observations are acquired, these characteristics are unknown and should be retrieved from the dataset itself. The presented solution is suited for airborne data analysis in order to be able to quickly filter and grid gravity observations in an easy way. Some innovative theoretical aspects focusing in particular on the theoretical covariance modelling are presented too. In the end, the goodness of the procedure is evaluated by means of a test on real data retrieving the gravitational signal with a predicted accuracy of about 0.4 mGal.  相似文献   

Quantification of the breakage of lump materials during handling operations     

C. S. Teo  A. G. Waters  S. K. Nicol 《International Journal of Mineral Processing》1990,30(3-4)

The strength of raw ironmaking materials is usually determined by tumble and shatter tests. Although an average result for a bulk sample is determined, the strength index is empirical and its numerical value cannot be used to predict the extent of breakage for a particular material handling circuit. A new experimental procedure has been developed to measure the strength based on the extent of breakage of agglomerates repeatedly dropped from a predetermined height. The drop procedure combined with impact and breakage theories has been used to quantify the effect of particle size and drop height on the extent of breakage of lump materials such as iron ore sinter, coke, coal and iron ore. Results from a plant trial indicated that the drop procedure could also be used to examine the stabilization effect of brittle material due to repeated dropping during handling.  相似文献