Investigating the Tsunamigenic Potential of Earthquakes from Analysis of the Informational and Multifractal Properties of Seismograms     

Luciano Telesca  Ashutosh Chamoli  Michele Lovallo  Tony Alfredo Stabile 《Pure and Applied Geophysics》2015,172(7):1933-1943

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Geophysical Exploration of Fractured-Media Aquifers at the Mexican Mesa Central: Satellite City,San Luis Potosí, Mexico     

Héctor López Loera  José Alfredo Ramos Leal  Pablo Dávila Harris  David Ernesto Torres Gaytan  Victor Julian Martinez Ruiz  Avto Gogichaishvili 《Surveys in Geophysics》2015,36(1):167-184

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Expansion of an invasive coral species over Abrolhos Bank,Southwestern Atlantic     

Thiago J.F. Costa  Hudson T. Pinheiro  João Batista Teixeira  Eric F. Mazzei  Leonardo Bueno  Mike S.C. Hora  Jean-Christophe Joyeux  Alfredo Carvalho-Filho  Gilberto Amado-Filho  Claudio L.S. Sampaio  Luiz A. Rocha 《Marine pollution bulletin》2014

Invasive coral species of the genus Tubastraea have been increasingly recorded in Southwestern Atlantic waters since the 1980s. Their invasion and infestation are mainly related to port and oil exploration activities. For the first time the presence of Tubastraea tagusensis colonies is reported in Espírito Santo State, colonizing a port shore area, and incrusting oil/gas platform structures situated in the southern Abrolhos Bank, which is part of the most important coral reef system of the South Atlantic Ocean. Tubastraea colonies exhibit fast growth and high recruitment rates, and colonized 40% of the analyzed structures in just four years. The projection of port and oil/gas industry growth for the Espírito Santo State (more than 300%) highlights an alert to the dispersal of this alien species to natural areas.  相似文献   

Charnock’s Roughness Length Model and Non-dimensional Wind Profiles Over the Sea   总被引：1，自引：1，他引：0  

Alfredo Peña  Sven-Erik Gryning 《Boundary-Layer Meteorology》2008,128(2):191-203

An analysis tool for the study of wind speed profiles over the water has been developed. The profiles are analysed using a modified dimensionless wind speed and dimensionless height, assuming that the sea surface roughness can be predicted by Charnock’s roughness length model. In this form, the roughness dependency on wind speed is extracted and the variations on the wind profile are due solely to atmospheric stability. The use of the Charnock’s non-dimensional wind profile is illustrated using data collected from a meteorological mast installed in the Danish North Sea. The best fit with the observed mean non-dimensional wind profile under neutral atmospheric conditions is found using a value of 1.2 × 10⁻² for Charnock’s parameter. The stability correction on the neutral wind profile suggested by the Businger-Dyer relations was found to perform well over the sea.  相似文献   

Measurements and Modelling of the Wind Speed Profile in the Marine Atmospheric Boundary Layer   总被引：1，自引：1，他引：0  

Alfredo Peña  Sven-Erik Gryning  Charlotte B. Hasager 《Boundary-Layer Meteorology》2008,129(3):479-495

We present measurements from 2006 of the marine wind speed profile at a site located 18 km from the west coast of Denmark in the North Sea. Measurements from mast-mounted cup anemometers up to a height of 45 m are extended to 161 m using LiDAR observations. Atmospheric turbulent flux measurements performed in 2004 with a sonic anemometer are compared to a bulk Richardson number formulation of the atmospheric stability. This is used to classify the LiDAR/cup wind speed profiles into atmospheric stability classes. The observations are compared to a simplified model for the wind speed profile that accounts for the effect of the boundary-layer height. For unstable and neutral atmospheric conditions the boundary-layer height could be neglected, whereas for stable conditions it is comparable to the measuring heights and therefore essential to include. It is interesting to note that, although it is derived from a different physical approach, the simplified wind speed profile conforms to the traditional expressions of the surface layer when the effect of the boundary-layer height is neglected.  相似文献   

Crust and upper mantle structure of the central Iberian Meseta (Spain)   总被引：2，自引：0，他引：2  

E. Banda  E. Suriñach  A. Aparicio  J. Sierra  E. Ruiz de la Parte 《Geophysical Journal International》1981,67(3):779-789

Summary. Quarry blasts recorded along three lines on the central Iberian Meseta are used in an attempt to interpret the crustal structure. The results of the interpretation of the data, together with published surface wave and earthquake data, suggest a layered structure of the crust having the following features: the basement, in some areas covered by up to 4 km of sediments, has a P -velocity of 6.1 km s⁻¹; a low-velocity layer, between 7 and 11 km depth, seems to exist on the basis of both P and S interpretation of seismic data; a thick middle crust of 12 km has a P -velocity of 6.4 km s⁻¹ and overlies a lower crust with a mean P -velocity of 6.9 km s⁻¹ and a possible slight negative gradient; the mean v _p/ v _s ratio for the crust is about 1.75; the Moho is reached at about 31 km depth and consists of a transition zone at least 1.5 km thick. The P -velocity of the upper mantle is close to 8.1 km s⁻¹ and the S -velocity about 4.5 km s⁻¹, which gives a v _p /v _s ratio of 1.8 for the uppermost mantle. A tentative petrological interpretation of the velocities and composition of the layers is given.  相似文献   

Chemical variations of muscovites from the Sierra de Guadarrama metamorphic area,Sistema Central,Spain     

J. López Ruiz  A. Aparicio  L. García Cacho 《International Journal of Earth Sciences》1980,69(1):94-106

Muscovites in metapelites belonging to the Chloritoid, Staurolite, Kyanite, Sillimanite-K feldspar and Sillimanite-K feldspar-Cordierite zones of the Sierra de Guadarrama metamorphic area, have a chemical composition close to the end member Ms (mean value around Ms 92); nevertheless, they show definite variations in Al₂O₃, K₂O and Na₂O contents and, to a lesser extent, in FeO and MgO.These chemical variations (i. e., a progressive decrease of celadonite content, a increase followed by a decrease in paragonite solid solution towards compositions close to the endmember muscovite) may be regarded as in a close relationship with metamorphic grade in the upper metamorphic zones (Chloritoid, Staurolite and Kyanite zones), but the corresponding variations in the remaining lower zones (that is, a slight increase in Fe and Mg coupled with a slight increase in Al^VI and Ti, and more or less abrupt changes in Na and K contents) can only be explained considering the interference of anatectic phenomena, which modificate the normal trends due to changes in metamorphic grade.As a consequence of these observations, it has been concluded that muscovite composition in metapelites can only be used as an indicator of metamorphic grade in conditions where partial melting phenomena are absent.

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Zusammenfassung Muskovite in Metapeliten, die zu den Chloritoid, Staurolit, Cyanit, Sillimanit-K-Feldspat und Sillimanit-K-Feldspat-Cordierit Zonen der Sierra Guadarrama Metamorphgebiet gehören, zeigen einen Chemismus, der sich dem Endglied Muskovit nähert (Durchschnitt etwa Ms 92). Es wurden trotzdem bestimmte Veränderungen in den Gehalten von hauptsächlich Al₂O₃, K₂O und Na₂O und in geringerem Ausmaß in FeO und MgO festgestellt.Diese chemischen Veränderungen (d. h. ein progressives Abnehmen des Keladonitgehaltes, gefolgt von einer Abnahme der Paragonitmischungsreihe in einer Richtung, die sich dem Endglied Muskovit annähert) können in einem engen Zusammenhang mit der höher metamorphen Zone (Chloritoid-, Staurolit- und Cyanitzonen) gesehen werden. Die entsprechenden Veränderungen in den tieferen Zonen (d. h. eine minimale Abnahme von Fe und Mg begleitet von einer ebenfalls geringen Abnahme von Al und Ti und einer mehr oder weniger abrupten Veränderung im Na- und K-Gehalt) können jedoch nur unter Berücksichtigung der Interferenz von anatektischen Phänomenen gesehen werden. Solche Phänomene modifizieren den normalen Trend durch eine Veränderung des Metamorphosegrades.Daraus folgt, daß die Muskovitzusammensetzung als Indikator des Metamorphosegrades nur in Abwesenheit von partiellen Schmelzphenomen gebraucht werden kann.

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Résumé Les muscovites des métapélites de la Sierra de Guadarrama, appartenant aux zones à chloritoïde, staurotide, disthène, sillimanite-feldspath potassique et sillimanite-feldspath potassique-cordierite, ont une composition chimique très proche de la valeur theorique (valeur moyenne Ms 92); néanmoins elles présentent une certaine variation dans les teneurs en Al₂O₃, K₂O et Na₂O et, à une moindre échelle, en FeO et MgO.Ces variations chimiques (diminution progressive en céladonite, augmentation suivie d'une diminution de la paragonite vers des compositions proches de la muscovite sensu stricto) que présentent les muscovites des zones à chloritoïde, staurotide et disthène sont étroitement liées aux zones métamorphiques superieures. Au contraire, les variations (legère augmentation des teneurs en Fe et Mg, legère diminution en Al^VI et Ti, et plus ou moins brusques variations en Na et K, respectivement) correspondantes des muscovites des zones de la sillimanite-feldspath potassique et de la sillimanite-feldspath potassiquecordiérite, ne peuvent s'expliquer que si l'on admis que, dans les niveaux plus métamorphiques, les muscovites souffrent une série de changements chimiques dûs au début de l'anatexie, laquelle modifie les tendances normales liées à l'intensité du metamorphisme.En conséquence, seules les muscovites des métapélites situées au-dessus de l'isograde du feldspath potassique, en dehors de toute fusion partielle peuvent être utilisées pour déterminer le degré de métamorphisme des roches qui les contiennent.

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, , , , -K- -- - , , 92 % . ₂₃, K₂ Na₂O FeO MgO. (.. , , , ) — , . (.. , ) , . . , .

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The effect of metasomatism on the Cr-PGE mineralization in the Finero Complex, Ivrea Zone, Southern Alps   总被引：1，自引：0，他引：1  

Giovanni Grieco  Alfredo Ferrario  Edmond A. Mathez 《Ore Geology Reviews》2004,24(3-4):299

The magmatic metasomatism that was responsible for producing chromitite–dunite bodies in the unusual phlogopite peridotite of the Finero Complex in Permian to Triassic times also influenced the Cr-platinum group elements (PGE) mineralization. At least the end stages of this metasomatism are recorded in compositional zoning of chromite grains in the podiform chromitite. Metasomatic melt, with or without vapor, reacted with chromite to produce core-to-rim Cr enrichment of extant chromite grains and was concurrent with pyroxene crystallization. Under conditions of lower melt/rock ratio, metasomatism resulted in core-to-rim Al enrichment in chromite and crystallization of amphibole between chromite and clinopyroxene. This early, high-temperature metasomatism is unrelated to the later and pervasive K-metasomatism that crystallized phlogopite and was associated with the intrusion of clinopyroxenite dikes that cut the peridotite. Much later, serpentinization of olivine locally depleted chromite in Al and enriched it in Fe and formed minor amounts of magnetite.The PGE, which are present mainly as laurite inclusions in chromite, were remobilized by the early metasomatism. This resulted in substantial variation in the PGE contents of chromitites and imposed a characteristic PGE pattern in which chondrite-normalized Os, Ir, Ru and Rh contents are high but Pt and Pd contents are low. The slopes of PGE chondrite-normalized concentration patterns are systematically related to absolute PGE abundance and to rock mode. Chromitites with low modal orthopyroxene, clinopyroxene, and amphibole exhibit negative PGE slopes and contain relatively high PGE concentrations, whereas chromitites rich in these silicate minerals have positive slopes and low PGE contents.  相似文献   

Detection of displacements on Tenerife Island, Canaries, using radar interferometry   总被引：1，自引：0，他引：1  

José Fernández  Rosana Romero  Daniel Carrasco  Kristy F. Tiampo  Gema Rodríguez-Velasco  Alfredo Aparicio  Vicente Araña  F. J. González-Matesanz 《Geophysical Journal International》2005,160(1):33-45

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Life‐cycle cost analysis based on a renewal model of earthquake occurrences     

Yuji Takahashi  Armen Der Kiureghian  Alfredo H‐S. Ang 《地震工程与结构动力学》2004,33(7):859-880

A decision methodology for the management of seismic risk of a single building is presented. The decision criterion aims at minimizing the expected life‐cycle cost, including the initial cost of the design and the expected cost of damage due to future earthquakes. The expected life‐cycle cost of each design alternative is formulated using a renewal model for the occurrence of earthquakes in a seismic source, which accounts for the temporal dependence between the occurrence of ‘characteristic’ earthquakes. The formulation involves the expected damage cost from an earthquake of specified magnitude in a given source. This term is estimated by simulating the processes of fault rupture, elastic wave propagation, surface soil amplification, dynamic structural response and generation of damage costs. As an example, the methodology is applied to an actual office building in Tokyo. A simple decision problem between two design alternatives is set: a bare steel moment frame, and the same frame equipped with oil dampers. Through this case study, the installation of the oil dampers is demonstrated to be effective in reducing the life‐cycle cost of the building under consideration. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献