A multidisciplinary approach integrating a wide data set ranging from bulk rock compositions of the erupted products to volcanic tremor, long‐period events, and tilt and gravity signals is used to investigate the source depth and magma dynamics of the 10 May 2008 lava fountain at Southeast crater (SEC) of Mount Etna. The investigation was undertaken in the framework of the previous 2007 explosive activity as well as the subsequent effusive eruption beginning 13 May 2008 and lasting up to July 2009. All the data concur in indicating that the 10 May lava fountain was generated by the fragmentation of a foam layer trapped at the top of a shallow reservoir, about 1500–1700 m below the summit of SEC. The shift from the episodic strombolian/lava fountain activity occurring in 2007 at SEC to the more powerful 10 May 2008 lava fountain is explained by the intrusion of a new more primitive magma into the shallow reservoir. Data also indicate that an attempted magma intrusion east of the summit area occurred during the 10 May fire fountain. This event caused the fracturing and weakening of the surrounding rocks and created a preferential pathway for the penetration of the magma that, only 3 days later, started to feed the 2008–2009 effusive eruption.
Geophysical (tilt, seismic tremor and gravity signals), geochemical (crater SO2flux) and infrared satellite measurements are presented and discussed to track the temporal evolution of the lava fountain episode occurring at Mt Etna volcano on 10 April 2011. The multi‐disciplinary approach provides insight into a gas‐rich magma source trapped in a shallow storage zone inside the volcano edifice. This generated the fast ascending gas‐magma dispersed flow feeding the lava fountain and causing the depressurization of a deeper magma storage. Satellite thermal data allowed estimation of the amount of erupted lava, which, summed to the tephra volume, yielded a total volume of erupted products of about 1 × 106 m3. Thanks to the daylight occurrence of this eruptive episode, the SO2 emission rate was also estimated, showing a degassing cycle reaching a peak of 15,000 Mg d−1 with a mean daily value of ∼5,700 Mg d−1. The SO2 data from the previous fountain episode on 17–18 February to 10 April 2011, yielded a cumulative degassed magma volume of about ∼10.5 × 106 m3, indicating a ratio of roughly 10:1 between degassed and erupted volumes. This volumetric balance, differently from those previously estimated during different styles of volcanic activities with long‐term (years) recharging periods and middle‐term (weeks to months) effusive eruptions, points toward the predominant role played by the gas phase in generating and driving this lava fountain episode.
To achieve a balance between uncertainty and\ud efficiency in gravity measurements, we have investigated\ud the applicability of combined measurements of absolute and\ud relative gravity as a hybrid method for volcano monitoring.\ud Between 2007 and 2009, three hybrid gravity surveys were\ud conducted at Mt Etna volcano, in June 2007, July 2008, and\ud July 2009. Absolute gravity data were collected with two\ud absolute gravimeters, which represent the state of the art in\ud recent advances in ballistic gravimeter technology: (1) the\ud commercial instrument FG5#238 and (2) the prototype instrument\ud IMGC-02. We carried out several field surveys and\ud confirmed that both the absolute gravimeters can still\ud achieve a 10 μGal or better uncertainty even when they\ud are operated in severe environmental conditions. The use\ud of absolute gravimeters in a field survey of the summit area\ud of Mt Etna is unprecedented. The annual changes of the\ud gravity measured over 2007–2008 and 2008–2009 provide\ud unequivocal evidence that during the 2007–2009 period,\ud two main phenomena of subsurface mass redistribution occurred\ud in distinct sectors of the volcano, accompanying\ud different eruptive episodes. From 2007 to 2008, a gravity\ud change of −60 μGal was concentrated around the North-\ud East Rift. This coincided with a zone affected by strong\ud extensional tectonics, and hence might have been related\ud to the opening of new voids. Between 2008 and 2009, a\ud North-South elongate feature with a maximum gravity\ud change of +80 μGal was identified in the summit craters\ud area. This is interpreted to indicate recharge of a deepintermediate\ud magma storage zone, which could have occurred\ud when the 2008–2009 eruption was still ongoing
The monitoring of Activities of Daily Living (ADL) is a fundamental task to implement a rigorous remote monitoring of weak users with particular regards to falls. Actually, unintentional falls cause a lot of hospitalizations and could produce serious consequence due to long-lie happenings. The widespread use of smartphones associated with the wide variety of embedded sensors would represent a suitable solution for ADL monitoring. This paper faces the development of fully smartphone based ADL detector which uses advanced signal processing to provide useful and reliable information for the efficient implementation of remote elderly monitoring. The developed strategy allows for ADL classification with sensitivity and specificity features in line with real applications in Ambient Assistive Living (AAL) context.
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