http://hdl.handle.net/2122/92 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/4150 Title: Strumentazioni in uso nel campo della petrologia sperimentale <br/> <br/>Authors: Misiti, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Iarocci, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia <br/> <br/>Abstract: This guide reports the description of the experimental apparata in use in the experimental petrology along with an accurate description of some applications of these instrumentations. After a brief introduction concerning what is the experimental petrology and what is used for, we provide a description of the starting materials used in this field of the Earth Sciences. Moreover, particular attention is focused on these apparata used all around the world. We, finally, introduce some examples of different studies conducted with the different experimental equipments. The aim of this guide is, then, to give information concerning the equipments and their potentiality. http://hdl.handle.net/2122/4147 Title: Electrical conductivity of a phonotephrite from Mt. Vesuvius: the importance of chemical composition on the lectrical conductivity of silicate melts <br/> <br/>Authors: Poe, B. T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Romano, C.; Università Roma Tre; Varchi, V.; Università Roma Tre; Misiti, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Scarlato, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia <br/> <br/>Abstract: The bulk electrical conductivity of the phonotephritic lava from the 1944 eruption of Mt Vesuvius was measured using complex impedance spectroscopy in a multianvil apparatus at 1 GPa and temperatures up to 700 °C. Melting experiments prior to the electrical measurements were also performed on this sample in a piston cylinder apparatus in order to gauge how bulk conductivity varies as a function of its melt fraction. Unlike the behaviour found in basaltic rocks in which conductivity increases with increasing melt fraction, we observe a conductivity decrease of the order of a factor of ten for samples at 700 °C ranging in melt fraction from 32 vol.% to completely molten.We attribute this anomalous behaviour to the progressive loss of highly conductive leucite upon melting. The addition of potassium to the melt phase, however, does not result in an increase of the total alkali concentration due to the melting of other mineral components. We also present an empirical model to predict the electrical conductivity of fully molten silicate liquids as a function of temperature and chemical composition, based on conductivity data for natural silicate liquids found in the literature. The inclusion of compositional terms reduces the error by more than a factor of four with respect to a composition independent, temperature-only parameterization. http://hdl.handle.net/2122/3695 Title: Alert system to mitigate tephra fallout hazards at Mt. Etna Volcano, Italy <br/> <br/>Authors: Alparone, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Sgroi, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Ferrari, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Lodato, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Reitano, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia <br/> <br/>Abstract: Volcanic eruptions may create a wide range of risks in inhabited areas and, as a consequence, major economic damage to the surrounding territory. An example of volcanic hazard was given between 1998 and 2001 by Mt. Etna volcano, in Italy, with its frequent paroxysmal explosive activity that caused more than a hundred fire-fountain episodes. In the period January–June 2000, in particular, 64 lava fountains took place at the Southeast Crater. During the most intense explosive phase of each episode, a sustained column often formed, reaching up to 6 km above the eruptive vent. Then, the column started to expand laterally causing more or less copious tephra fallout on the slopes of Etna; ash and lapilli, therefore, constituted a serious danger for vehicular and air traffic. A software and hardware warning system was developed to mitigate the volcanic hazard indicating the areas affected by potential ash and lapilli fallout. The alert system was mainly based on the good correspondence between the pattern of volcanic tremor amplitude and the evolution of explosive activity. When a fixed tremor threshold was exceeded, a semiautomatic process started to send faxes to Civil Defence and Municipalities directly affected by tephra fallout, together with information on wind directions from the Meteorological Office. The application of this methodology, during the last 14 eruptive episodes in 2000 and the 14 events occurred in 2001, demonstrated the good correspondence between the forecasts on the areas affected by tephra fallout and the effective tephra distribution on land. Despite the integrity of the performance provided by the alert system, small discrepancies occurred in the technical procedure of alerting, for which possible solutions have been discussed. The improvement of this type of system, could become basic for the Etnean region and be proposed for similar volcanic areas throughout the world. http://hdl.handle.net/2122/3101 Title: Modelling long term ground deformation by a submerged archaeological site: the case of Basiluzzo island. <br/> <br/>Authors: Tallarico, A.; Università di Bologna; Dragoni, M.; Università di Bologna; Anzidei, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Esposito, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia <br/> <br/>Abstract: We estimate the long-term vertical deformation of Basiluzzo island, located in the volcanic arc of the Aeolian Islands, Italy, by inferring the subsidence of a Roman age submerged wharf dated 2000 ± 50 years ago.We model the crustal deformation that produced this displacement as a cooling magma chamber emplaced during the formation of the island. This is the first attempt to model crustal deformation using the subsidence of a submerged archaeological structure. Nowadays the top of the wharf, which can be considered an unconventional leveling benchmark, is located near Punta Levante, at an average depth of 3.20 ± 0.10mbelow actual sea level, and it is still in good conservation. Its present location is due to combined effect of sea level rise and volcanic and tectonic activity that occurred since it was built. Taking into account the architectural features of the wharf and that the mean sea level rise of the Mediterranean sea has been estimated as 0.45 m during the last 2000 years [Flemming andWebb, 1986],we estimate a total subsidence of 3.75 ± 0.10m, at a rate of about 1.87 mm yr 1 [Anzidei et al., 2002]. We propose a possible mechanism for the long-term subsidence, which occurred on a timescale of thousands of years, by considering the Earth’s crust as a Maxwell body. We assume that the magmatic source is located directly beneath Basiluzzo dome and underwent progressive solidification and subsequent volume reduction since its emplacement 50,000 years ago.