Lava flow field development and lava tube formation during the 1858–1861 eruption of Vesuvius (Italy), unravelled by historical documentation, lidar data and 3D mapping

Somma-Vesuvius is well known for its powerful Plinian explosive eruptions, however during the last eruptive cycle (1631–1944), persistent activity took place on the stratovolcano as mild and violent Strombolian, and effusive eruptions, forming more than one hundred lava flow fields. An important mechanism of lava transport within lava flow fields is the formation and development of lava tubes. The presence of lava tubes in a flow field can greatly increase their distance of emplacement. Observations of lava tubes at Vesuvius have been documented in historical records and speleological reports but no modern scientific studies are available. This work focuses on lava tubes formed in the compound lava flow field of the long-lived 1858 eruption (from 27 May 1858 to 12 April 1861) that was fed by seven eruptive fissures. The temporal and spatial evolution of the 1858 lava flow field was reconstructed using historical documentation. The exposed lava flow field surface was analysed using a 1-m resolution lidar Digital Surface Model (DSM). Surveys to fully digitize the interior and the overlying surface of the largest lava tube found in the 1858 lava flow field were conducted using a terrestrial laser scanner, optical cameras, and an Unmanned Aerial Vehicle (UAV). The accurate 3D model obtained was used to precisely quantify the inner dimensions and to better constrain the morphologies of the lava tube. Observed internal features were described and used to gain information on the formation and activity of the lava tube. Our data allowed us to understand that the described lava tube formed as an inflated lava flow inside which lava flowed through during an extended period ultimately draining out completely at the end of the eruption. Understanding how lava flow fields develop and how lava tubes form on Vesuvius is crucial to re-evaluate the last effusive activity of the volcano and its impact on hazard assessment

Magma emission rates fromshallow submarine eruptions using airborne thermal imaging

The effusion rate is the most important parameter to gatherwhen a volcanic eruption occurs, because it controls the way inwhich a lava body grows, extends and expands, influencing its dimensional properties. Calculation of lava flow volume from thermal images collected by helicopter surveys has been largely used during the last decade for monitoring subaerial effusive eruptions. However, due to the depths where volcanic activity occurs, monitoring submarine volcanic eruptions is a very difficult task. The 2011–2012 submarine volcanic eruption at El Hierro, Canary Islands, has provided a unique and excellent opportunity to monitor eruptive processes occurring on the seabed. The use of a hand-held thermal camera during daily helicopter flights allowed us to estimate for the first time the daily and total erupted magma volumes from a submarine eruption. The volume of magma emitted during this eruption has been estimated at 300 Mm3, giving an average effusion rate of ~25 m3 s−1. Thermal imagery by helicopter proved to be a fast, inexpensive, safe and reliable technique of monitoring volcanic eruptions when they occur on the shallow seabed.This research was financially supported by the projects MAKAVOL (MAC/3/C161) from the European Union MAC 2007–2013 Transnational Cooperation Program as well as from the Cabildo Insular de Tenerife. We are also grateful to the staff of El Hierro airport (AENA) for providing logistical support.Published219-2255V. Sorveglianza vulcanica ed emergenzeJCR Journalrestricte

MISR observations of Etna volcanic plumes

In the last twelve years, Mt. Etna, located in eastern Sicily, has produced a great number of explosive eruptions. Volcanic plumes have risen to several km above sea level and created problems for aviation and the communities living near the volcano. A reduction of hazards may be accomplished using remote sensing techniques to evaluate important features of volcanic plumes. Since 2000, the Multiangle Imaging SpectroRadiometer (MISR) on board NASA’s Terra spacecraft has been extensively used to study aerosol dispersal and to extract the three-dimensional structure of plumes coming from anthropogenic or natural sources, including volcanoes. In the present work, MISR data from several explosive events occurring at Etna are analyzed using a program named MINX (MISR INteractive eXplorer). MINX uses stereo matching techniques to evaluate the height of the volcanic aerosol with a precision of a few hundred meters, and extracts aerosol properties from the MISR Standard products. We analyzed twenty volcanic plumes produced during the 2000, 2001, 2002–03, 2006 and 2008 Etna eruptions, finding that volcanic aerosol dispersal and column height obtained by this analysis is in good agreement with ground-based observations. MISR aerosol type retrievals: (1) clearly distinguish volcanic plumes that are sulphate and/or water vapor dominated from ash-dominated ones; (2) detect even low concentrations of volcanic ash in the atmosphere; (3) demonstrate that sulphate and/or water vapor dominated plumes consist of smaller-sized particles compared to ash plumes. This work highlights the potential of MISR to detect important volcanic plume characteristics that can be used to constrain the eruption source parameters in volcanic ash dispersion models. Further, the possibility of discriminating sulphate and/or water vapor dominated plumes from ash-dominated ones is important to better understand the atmospheric impact of these plumesPublishedD062101.5. TTC - Sorveglianza dell'attività eruttiva dei vulcaniJCR Journalrestricte

The first period of the 2002 Etna eruption (27 October-5 November): preliminary results

We report on the first period of the 2002 Etna eruption started on 27th October and ended on 5th November, occurring 15 months after the end of the 2001 eruption. Volcanological and geochemical data are presented in order to characterize the complex intrusion mechanism that contemporaneously involved the NE and S flanks of the volcano. Preliminary data outline that two distinct magma intrusions fed the eruptive fissures. Strong fire fountain activity mainly from the S fissure, produced copious ash fall in eastern Sicily, causing prolonged closure of Catania and Reggio Calabria airports. Lava emitted from the NE fissure formed a 6.2 km long lava flow field that destroyed the tourist facilities of Piano Provenzana area and part of Linguaglossa pine forest.Published1-10reserve

Reconstruction of the eruptive activity on the NE sector of Stromboli volcano: timing of flank eruptions since 15 ka

A multidisciplinary geological and compositional investigation allowed us to reconstruct the occurrence of flank eruptions on the lower NE flank of Stromboli volcano since 15 ka. The oldest flank eruption recognised is Roisa, which occurred at ~15 ka during the Vancori period, and has transitional compositional characteristics between the Vancori and Neostromboli phases. Roisa was followed by the San Vincenzo eruption that took place at ~12 ka during the early stage of Neostromboli period. The eruptive fissure of San Vincenzo gave rise to a large scoria cone located below the village of Stromboli, and generated a lava flow, most of which lies below sea level. Most of the flank eruptions outside the barren Sciara del Fuoco occurred in a short time, between ~9 and 7 ka during the Neostromboli period, when six eruptive events produced scoria cones, spatter ramparts and lava flows. The Neostromboli products belong to a potassic series (KS), and cluster in two differently evolved groups. After an eruptive pause of ~5,000 years, the most recent flank eruption involving the NE sector of the island occurred during the Recent Stromboli period with the formation of the large, highly K calc-alkaline lava flow field, named San Bartolo. The trend of eruptive fissures since 15 ka ranges from N30°E to N55°E, and corresponds to the magma intrusions radiating from the main feeding system of the volcano

Mammalian sex determination—insights from humans and mice

Disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Many of the genes required for gonad development have been identified by analysis of DSD patients. However, the use of knockout and transgenic mouse strains have contributed enormously to the study of gonad gene function and interactions within the development network. Although the genetic basis of mammalian sex determination and differentiation has advanced considerably in recent years, a majority of 46,XY gonadal dysgenesis patients still cannot be provided with an accurate diagnosis. Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. Here, we review our current knowledge of mammalian sex determination drawing on insights from human DSD patients and mouse models