The exceptional activity and growth of the Southeast Crater, Mount Etna (Italy), between 1996 and 2001     

Boris Behncke  Marco Neri  Emilio Pecora  Vittorio Zanon 《Bulletin of Volcanology》2006,69(2):149-173

Between 1971 and 2001, the Southeast Crater was the most productive of the four summit craters of Mount Etna, with activity that can be compared, on a global scale, to the opening phases of the Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea volcano, Hawai‘i. The period of highest eruptive rate was between 1996 and 2001, when near-continuous activity occurred in five phases. These were characterized by a wide range of eruptive styles and intensities from quiet, non-explosive lava emission to brief, violent lava-fountaining episodes. Much of the cone growth occurred during these fountaining episodes, totaling 105 events. Many showed complex dynamics such as different eruptive styles at multiple vents, and resulted in the growth of minor edifices on the flanks of the Southeast Crater cone. Small pyroclastic flows were produced during some of the eruptive episodes, when oblique tephra jets showered the steep flanks of the cone with hot bombs and scoriae. Fluctuations in the eruptive style and eruption rates were controlled by a complex interplay between changes in the conduit geometry (including the growth of a shallow magma reservoir under the Southeast Crater), magma supply rates, and flank instability. During this period, volume calculations were made with the aid of GIS and image analysis of video footage obtained by a monitoring telecamera. Between 1996 and 2001, the bulk volume of the cone increased by ~36×10⁶ m³, giving a total (1971–2001) volume of ~72×10⁶ m³. At the same time, the cone gained ~105 m in height, reaching an elevation of about 3,300 m. The total DRE volume of the 1996–2001 products was ~90×10⁶m³. This mostly comprised lava flows (72×10⁶ m³) erupted at the summit and onto the flanks of the cone. These values indicate that the productivity of the Southeast Crater increased fourfold during 1996–2001 with respect to the previous 25 years, coinciding with a general increase in the eruptive output rates and eruption intensity at Etna. This phase of intense summit activity has been followed, since the summer of 2001, by a period of increased structural instability of the volcano, marked by a series of important flank eruptions.  相似文献   

Magnetic and ground probing radar measurements for soil pollution mapping in the industrial area of Val Basento (Basilicata Region, Southern Italy): a case study     

D. Chianese  M. D’Emilio  M. Bavusi  V. Lapenna  M. Macchiato 《Environmental Geology》2006,49(3):389-404

The joint application of electromagnetic techniques for near-surface exploration is a useful tool for soil pollution monitoring and can also contribute towards describing the spatial distribution of pollutants. The results of a geophysical field survey that was carried out for characterizing the heavy metal and waste disposal soil pollution phenomena in the industrial area of Val Basento (Basilicata region, Southern Italy) are presented here. First, topsoil magnetic susceptibility measurements have been carried out for defining the spatial distribution of superficial pollution phenomena in the investigated area. Second, detailed and integrated measurements based on a high-resolution magnetic mapping and ground probing radar (GPR) profiling have been applied to investigate the subsurface in two industrial areas located in more polluted sites that were identified during the first phase. Our monitoring strategy discloses the way to rapidly define the zone characterized by high pollution levels deriving from chemical industries and traffic emissions and to obtain the way information about the presence of local buried sources of contamination.  相似文献   

Palaeointensity record through the Lower Mammoth reversal from the Waianae volcano, Hawaii     

Mimi J. Hill  John Shaw  Emilio Herrero-Bervera 《Earth and Planetary Science Letters》2005,230(3-4):255-272

The normal to reverse Lower Mammoth reversal (3.33 Ma) has been recorded in several sequences of lava from the Waianae Volcano, the Island of Oahu, Hawaii. 137 samples from 29 flows from the Pu'u Paheehee section have been the subject of a palaeointensity study using the microwave technique. Duplicate sister samples from the directional study of Herrero-Bervera and Valet (Earth Planet. Sci. Lett. 171 (1999) 139–148) were used. Microwave demagnetisation was carried out on all samples and the directions compared to the published flow mean directions. Microwave palaeointensity experiments were carried out on all accepted samples using the 8.2 GHz and 14 GHz microwave systems. The perpendicular applied field palaeointensity method and a Coe analogue method were used. Eighty-four samples from 24 flows gave acceptable palaeointensity results. The results indicate that the geomagnetic field was low (mean 5.9±1.3 μT (N=7)) prior to the transitional directions. During the first stage of the reversal the field remains low. Results however could only be obtained from three transitional flows. The field then strongly recovers with very high intensity (70 μT) and reversed direction. After this the intensity decreases before the field becomes transitional again for a cluster of four flows. The field does not reduce as much as previously, rather it is about twice the pre reversal intensity. For the final section of reversed flows the intensity is more than twice the pre reversal mean value, 15.1±5.9 μT (N=7). Whilst some similarities are seen between this reversal and other reversals of different ages and locations there is not enough data at present to say whether there is any systematic behaviour.  相似文献   

Structural and geochemical data on the Rio Magno Unit: evidence for a new 'Apenninic' ophiolitic unit in Alpine Corsica and its geodynamic implications     

Elisa Padoa  Emilio Saccani  & Michel Durand-Delga 《地学学报》2001,13(2):135-142

The Rio Magno Unit (RMU) tectonically overlies the Schistes Lustrés units in south-eastern Alpine Corsica. It is represented by an ophiolitic sequence, showing remarkable differences with respect to the commonly recognized Corsican ophiolites. This unit can be distinguished from the Schistes Lustrés by the lack of HP–LT metamorphism, reflecting its different geodynamic setting, although both were involved early in the same tectonic events. Similarly, the RMU can be distinguished from the Balagne Unit by the presence of normal-MORB basalts and the scarcity of continent-derived sedimentary input, testifying to a different oceanic palaeogeographical setting. Moreover, the petrochemical and stratigraphic features of the RMU ophiolitic sequence show close analogies with the Internal Ligurides of the Northern Apennines. The RMU represents the first record of a nonmetamorphic 'Apenninic'-type ophiolitic unit in Alpine Corsica, supporting the hypothesis that the Alpine Corsica – Northern Apennine system represents a double-vergent accretionary wedge.  相似文献   

Hydrothermalisme anté-Hercynien en Sud-Ibérie : apport de la géochimie isotopique du plombPre-Hercynian hydrothermalism in South Iberia: lead isotope geochemistry constraints     

Éric Marcoux  Emilio Pascual  Jérôme Onézime 《Comptes Rendus Geoscience》2002,334(4):259-265

Lead isotope study has been performed on massive sulphide deposits of Ossa-Morena and Aracena Belt (South Iberia). Results suggest the existence of at least two ancient hydrothermal events. The first one, Upper Brioverian in age (～600–570 Ma), gave birth to Maria-Luisa and Puebla de la Reina massive sulphide deposits; it thus confirms the existence of a Cadomian orogen in South Iberia. Isotopic compositions indicate a local contribution of mantle-derived material (Maria Luisa mine), confirming the presence of ancient oceanic crust in Aracena Belt. This mineralising event seems to extend till the Armorican Massif. The second episode, Eo-Hercynian in age (～400–350 Ma) has allowed genesis of massive sulphide deposits of la Nava Paredon and Aguas Blancas, and could be coeval with the emplacement of South-Iberian massive sulphide ore deposits in the neighbouring South-Portuguese Zone. A more continental crustal source for later ore deposits could explain the much more important metal accumulation in this zone. To cite this article: É. Marcoux et al., C. R. Geoscience 334 (2002) 259–265.  相似文献   

A teleseismic shear-wave splitting study to investigate mantle flow around South America and implications for plate-driving forces   总被引：2，自引：0，他引：2  

George Helffrich  Douglas A. Wiens  Emilio Vera  Sergio Barrientos  Patrick Shore  Stacey Robertson  Rodrigo Adaros 《Geophysical Journal International》2002,149(1):F1-F7

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Evaluation of climatic change through harmonic analysis     

Roberto Rodriguez  M. Carmen Llasat  Emilio Rojas 《Natural Hazards》1994,9(1-2):5-16

In the present work, a precipitation and temperature series from Barcelona (Spain) are analysed in order to detect the possible existence of climatic changes or cycles. The analysis is carried out both from the temporal and spectral standpoints. The techniques used range from the classical periodogram and Blackman-Tukey method through to the Maximum Entropy method. The results do not show the existence of climatic cycles, though they do show a clear tendency toward increased precipitation and decreased temperature, since the last years of series.  相似文献   

Sopra un'onda lenta superficiale provocata da esplosione vicina: II     

Dott. Ing. Emilio Perri 《Pure and Applied Geophysics》1954,29(1):84-105

Riassunto L'A. completa le proprie ricerche sull'onda superficiale () già trattata in precedenza (Parte I). Gli argomenti qui svolti rispettivamente riguardano: 1) la distribuzione spaziale del vettore spostamento totale e, correlativamente, il «locus» (traiettoria ideale stazionaria) per un punto del mezzo legato allo «strain» periodico dell'onda (); 2) il rapporto delle componenti massimali, nonchè la velocità di gruppo del moto vibratorio studiato; 3) la determinazione delle costanti elastiche e di una roccia superficiale della crosta terrestre, attraverso un metodo suggerito dall'A. e basato sulla registrazione di impulsi del tipo () (Esperienze di Genova-Fegino, 1939); 4) una dimostrazione analitica della divergenza geometrica fra i raggi sismici (rettilinei) relativi ad un'onda piana teorica ed i raggi (curvilinei) lungo i quali fluisce l'energia del moto ondoso esaminato.

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Summary The Author completes his analytical investigation on the surfacewave (), in continuation of Part I. Following subjects are treated: 1) The spatial distribution of the displacement vector and, correlatively, the trajectory-equation of a point displaced by periodic strain; 2) The ratio between the maximal components of ()-wave motion, as well as the corresponding group velocity formula; 3) An estimate of the elastic constants and of surface-rocks, trough the dynamic method give by the Author, based on the recording of any pulses () spread by an explosion (Genoa's experiences, 1939); 4) the analytical demonstration of the geometric divergence existing between seismic and energetic rays of this surface-waves.

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R.L. Harkan, K.E. Kolm and E.D. Gutentag, Water-Well Design and Construction, Elsevier, Amsterdam, Netherlands (1989), p. 205.     

Emilio Custodio 《Engineering Geology》1991,31(3-4):376-377

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Über die Altersbestimmung des Braunkohlenbeckens Mercure (Süditalien)     

Dr. Emilio Ricciardi 《International Journal of Earth Sciences》1964,53(2):866-870

Zusammenfassung Die Ablagerung der Braunkohlenvorkommen im Mercure-Becken (Süditalien) wurde in die Nachmindelzeit gelegt. Vergleiche mit anderen italienischen Braunkohlenablagerungen bekannten Alters bestätigten die Ergebnisse. Das für das Unterpleistozän typische Waldbild mit Carietum u. a. konnte nie im Mercurebecken festgestellt werden. Pollen von Carya und Pterocarya, die die Ablagerungen in das Altpleistozän stellen würden, sind sehr wahrscheinlich eingeschwemmt worden. Eine weitere Bestätigung liefern die Reste von Elephas antiquus. Außerdem kommen in den Hangendmergeln der Mercure-Schichten Schlacken von dem noch im Quartär tätigen Vulkan Vulture vor.

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The soft-coal (Braunkohlen-) deposits of the Mercure-Basin (S.-Italy) are Post-Mindel in age. Proofs are given.

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Résumé Le gisement de lignite dans le bassin de Mercure (Italie du Sud), s'est formé après le Mindel. Des comparaisons avec d'autres gisements italiens de lignite d'âge connu confirment ce résultat. La forêt à Carietum typique du Pléistocène inférieur n'a jamais pu être établie pour le bassin de Mercure. Des pollen de Carya et de Pterocarya, qui reporteraient le gisement au Pléistocène inf., résultent très probablement d'entraînements. Une autre confirmation en est fournie par des restes d'Elephas antiquus.En outre on trouve dans les marnes du toit des couches de Mercure des scories du volcan Vulture qui était encore en activité au Quaternaire.

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