Volcanic conduit migration over an active basement landslide at Mount Etna (Italy)

The flanks of volcanoes may slide in response to the loading of the edifice on a weak basement, magma push, and/or to tectonic stress. However, examples of stratovolcanoes emplaced on active landslides are lacking and the possible effects on the volcano dynamics unknown. Here, we use aeromagnetic data to construct a three-dimensional model of the clay-rich basement of Etna volcano (Italy). We provide evidence for a large stratovolcano growing on a pre-existing basement landslide and show that the eastern Etna flank, which slides toward the sea irrespective of volcanic activity, moves coherently with the underlying landslide. The filling of the landslide depression by lava flows through time allows the formation of a stiffness barrier, which is responsible for the long-term migration of the magma pathways from the coast to the present-day Etna summit. These unexpected results provide a new interpretation clue on the causes of the volcanic instability processes and of the mechanisms of deflection and migration of volcanic conduits

The earliest open conduit eruptive center of the Etnean region: evidence from aeromagnetic, geophysical, and geological data

At Mount Etna, the present-day active volcano is an open conduit structure characterized by continuous eruptive activity. Such conditions have been thought unique in the evolution of the Etnean volcano as well as in the Mediterranean region. However, a review study of available geophysical data and models, combined with geological records, petrographic and geochemical considerations, has led us to consider that a large area of about 28 km2 located in Val Calanna, on the eastern side of Valle del Bove, can be interpreted as the site of an old open conduit volcano. A dyke swarm outcrops in the area, whose deep alteration and fumarolization can be attributed to the sustained passage of volcanic gases over long periods. Radiometric dating yields an age of about 129 ka. This finding sheds new light on the evolution of Mount Etna volcano, indicating that the tectonic conditions leading to an open conduit volcano must also have been active in the past.Published501V. Storia e struttura dei sistemi vulcaniciJCR Journalrestricte

Volcanic conduit migration over an active basement landslide at Mount Etna (Italy)

The flanks of volcanoes may slide in response to the loading of the edifice on a weak basement, magma push, and/or to tectonic stress. However, examples of stratovolcanoes emplaced on active landslides are lacking and the possible effects on the volcano dynamics unknown. Here, we use aeromagnetic data to construct a three-dimensional model of the clay-rich basement of Etna volcano (Italy). We provide evidence for a large stratovolcano growing on a pre-existing basement landslide and show that the eastern Etna flank, which slides toward the sea irrespective of volcanic activity, moves coherently with the underlying landslide. The filling of the landslide depression by lava flows through time allows the formation of a stiffness barrier, which is responsible for the long-term migration of the magma pathways from the coast to the present-day Etna summit. These unexpected results provide a new interpretation clue on the causes of the volcanic instability processes and of the mechanisms of deflection and migration of volcanic conduits.Published52931V. Storia e struttura dei sistemi vulcaniciJCR Journalrestricte

Geomorphological and geophysical investigations for the characterization of the Roman Carsulae site (Tiber basin, Central Italy)

This paper aims to bring to light the possible linkage between karstic phenomena and the human occupation of the Roman site of Carsulae (Tiber basin, Central Italy). Dolines are a typical morphological expression of karst rocks dissolution and collapse and, usually, they represent a potential hazard for human activities and, in particular, in the care and maintenance of cultural heritage sites. In this study, we observed that the development of a subsidence doline caused severe damage to some archaeological structures at Carsulae monumental site. According to the results obtained in our investigation, three sites at least with karst dissolution phenomena in the shallow calcareous tufa layer have been identified. One of them subsided probably in Roman times and produced a sharp deformation of the decumanus. In order to understand the evolution of this territory an integrated geomorphological and geophysical survey was carried out. The combination between the information derived from different geophysical techniques, such as: Electrical Resistivity Tomography (ERT), Frequency-Domain Electromagnetism (FDEM), Ground Penetrating Radar (GPR) clearly pointed out that the calcareous tufa layer is characterized by an irregular geometry and resulted affected by karst dissolution in several parts of the investigated area. Four boreholes opportunely located, provided direct information about the depth and the alteration of the calcareous tufa basement and precious calibration data for the geophysical methods. This study contributes to improve our knowledge on the evolution of the Carsulae archaeological site providing a new insight into the adaptation of ancient human societies in this problematic territory

High resolution magnetic anomaly map of Tenerife, Canary Islands

This study presents magnetic anomaly data from a new high-resolution, low-altitude helicopter-borne magnetic survey recently collected on and offshore Tenerife in the Canary Archipelago. The Italian Istituto Nazionale di Geofisica e Vulcanologia (INGV) in collaboration with the Museo Nacional de Ciencias Naturales of the CSIC of Spain conducted the survey in 2006. The data for Tenerife and surrounding marine areas were processed into digital total intensity magnetic anomalies for geomagnetic epoch 2006.4. Relative to previously available higher altitude magnetic survey data, the new survey mapped higher resolution anomalies with significantly improved spatial details, especially over the Las Cañadas caldera and Teide-Pico Viejo complex in the central part of the island. A good correlation is evident between known structural geology and the magnetic anomalies, where the new shorter wavelength anomalies facilitate more detailed and comprehensive geologic interpretations

Total thyroidectomy with ultrasonic dissector for cancer: multicentric experience

<p>Abstract</p> <p>Background</p> <p>We conducted an observational multicentric clinical study on a cohort of patients undergoing thyroidectomy for thyroid carcinoma. The aim of this study was to evaluate the benefits of the use of ultrasonic dissector (UAS) <it>vs.</it> the use of a conventional technique (vessel clamp and tie) in patients undergoing thyroid surgery for cancer.</p> <p>Methods</p> <p>From June 2009 to May 2010 we evaluated 321 consecutive patients electively admitted to undergo total thyroidectomy for thyroid carcinoma. The first 201 patients (89 males, 112 females) presenting to our Department underwent thyroidectomy with the use of UAS while the following 120 patients (54 males, 66 females) underwent thyroidectomy performed with a conventional technique (CT): vessel clamp and tie.</p> <p>Results</p> <p>The operative time (mean: 75 min in UAS <it>vs.</it> 113 min in CT, range: 54 to 120 min in UAS <it>vs.</it> 68 to 173 min in CT) was much shorter in the group of thyroidectomies performed with UAS. The incidence of transient laryngeal nerve palsy (UAS 3/201 patients (1.49%); CT 1/120 patients (0.83%)) was higher in the group of UAS; the incidence of permanent laryngeal nerve palsy was similar in the two groups (UAS 2/201 patients (0.99%) <it>vs.</it> CT 2/120 patients (1.66%)). The incidence of transient hypocalcaemia (UAS 17/201 patients (8.4%) <it>vs.</it> CT 9/120 patients (7.5%)) was higher in the UAS group; no relevant differences were reported in the incidence of permanent hypocalcaemia in the two groups (UAS 5/201 patients (2.48%) <it>vs.</it> 2/120 patients (1.66%)). Also the average postoperative length of stay was similar in two groups (2 days).</p> <p>Conclusion</p> <p>The only significant advantage proved by this study is represented by the cost-effectiveness (reduction of the usage of operating room) for patients treated with UAS, secondary to the significant reduction of the operative time. The analysis failed to show any advantages in terms of postoperative transient complications in the group of patients treated with ultrasonic dissector: transient laryngeal nerve palsy (1.49% in UAS <it>vs.</it> 0.83% in CT) and transient hypocalcaemia (8.4% in UAS <it>vs.</it> 7.5%in CT). No significant differences in the incidence of permanent laryngeal nerve palsy (0.8% in UAS <it>vs.</it> 1.04% in CT) and permanent hypocalcaemia (2.6% in UAS <it>vs.</it> 2.04% in CT) were demonstrated. The level of surgeons’ expertise is a central factor, which can influence the complications rate; the use of UAS can only help surgical action but cannot replace the experience of the operator.</p