Search results for "caldera"

The structure of a hydrothermal system from an integrated geochemical, geophysical, and geological approach: The Ischia Island case study

2011

The complexity of volcano-hosted hydrothermal systems is such that thorough characterization requires extensive and interdisciplinary work. We use here an integrated multidisciplinary approach, combining geological investigations with hydrogeochemical and soil degassing prospecting, and resistivity surveys, to provide a comprehensive characterization of the shallow structure of the southwestern Ischia's hydrothermal system. We show that the investigated area is characterized by a structural setting that, although very complex, can be schematized in three sectors, namely, the extra caldera sector (ECS), caldera floor sector (CFS), and resurgent caldera sector (RCS). This contrasted structura…

Resurgent uplift at large calderas and relationship to caldera-forming faults and the magma reservoir: new insights from the Neapolitan Yellow Tuff c…

2021

<p>Resurgence uplift is the rising of the caldera floor, mainly due to pressure or volume changes in the magma reservoir. Identifying resurgence structures and understanding their relationship to the magmatic reservoir is challenging. We investigate the resurgence structures of the Neapolitan Yellow Tuff (NYT) caldera (Italy) by integrating bathymetric data, high-resolution seismic profiles and Differential Synthetic-Aperture Radar Interferometry data. Our results show that the resurgent area is manifested as 1) a central dome constituted by two main blocks bounded by NNE-SSW trending faults, 2) an apical graben developed on top of the most uplifted block, 3) a peripheral zone…

Volatiles in pantellerite magmas: A case study of the Green Tuff Plinian eruption (Island of Pantelleria, Italy)

2013

Abstract The Green Tuff (GT) Plinian eruption, the largest in magnitude at Pantelleria, erupted 3 to 7 km3 DRE of pantellerite magma and a small volume of trachyte. Fifty-nine anorthoclase-hosted melt inclusions from the two basal pumice members were analyzed by FT-IR spectroscopy in order to assess the pre-eruptive H2O content in the pantellerite melt. Microanalytical methods were used to determine major element, Cl, F and S contents. Melt inclusions and glassy groundmasses have a nearly homogeneous pantelleritic composition (peralkaline index = 1.9-2.2) and variable water contents ranging from 1.4 to as high as 4.2 wt %, i.e. much higher than the 1.4 wt % of earlier published studies. The…

Volcano seismicity and ground deformation unveil the gravity-driven magma discharge dynamics of a volcanic eruption.

2015

Effusive eruptions are explained as the mechanism by which volcanoes restore the equilibrium perturbed by magma rising in a chamber deep in the crust. Seismic, ground deformation and topographic measurements are compared with effusion rate during the 2007 Stromboli eruption, drawing an eruptive scenario that shifts our attention from the interior of the crust to the surface. The eruption is modelled as a gravity-driven drainage of magma stored in the volcanic edifice with a minor contribution of magma supplied at a steady rate from a deep reservoir. Here we show that the discharge rate can be predicted by the contraction of the volcano edifice and that the very-long-period seismicity migrat…

Composition and distribution of volcanic gases inside the Lakki Caldera (Nisyros, Greece): preliminary results

2013

Predicting the landslides triggered by the 2009 96E/Ida tropical storms in the Ilopango caldera area (El Salvador, CA): optimizing MARS-based model b…

2019

The main topic of this research was to evaluate the effect in the performance of stochastic landslide susceptibility models, produced by differences between the triggering events of the calibration and validation datasets. In the Caldera Ilopango area (El Salvador), MARS (multivariate adaptive regression splines)-based susceptibility modeling was applied using a set of physical–environmental predictors and two remotely recognized landslide inventories: one dated at 2003 (1503 landslides), which was the result of a normal rainfall season, and one which was produced by the combined effect of the Ida hurricane and the 96E tropical depression in 2009 (2237 landslides). Both the event inventorie…

Volcanological evolution of Pantelleria Island (Strait of Sicily) peralkaline volcano: a review

2022

International audience; Pantelleria volcano has a particularly intriguing evolutionary history intimately related to the peralkaline composition of its explosively erupted magmas. Due to the stratigraphic complexity, studies over the last two decades have explored either only the pre-Green Tuff ignimbrite volcanism or the post-Green Tuff activity. We here focus on the whole evolutionary history, detailing the achievements since the first pioneering studies, in order to illustrate how the adoption and integration of progressively more accurate methods (40 Ar/ 39 Ar, paleomagnetism, petrography, and detailed field study) have provided many important independent answers to unresolved questions…

The Nahe Caldera — A resurgent Caldera in the permocarboniferous Saar Nahe basin, SW-Germany

1984

In the Saar Nahe basin, SW-Germany, a large resurgent caldera complex of Lower Permian age was recognized recently, for which the name „Nahe Caldera” is proposed.

Perforazione della Caldera dei Campi Flegrei - Una proposta anfibia IODP-ICDP

2018

Active calderas are major volcanic features of the Earth’s crust associated with shallow magma reservoirs, high geothermal gradients, and geodynamic unrests often documented through historical time. As large caldera-forming eruptions are also among the most catastrophic events that may affect the Earth’s surface, calderas are ostensibly the sites of major interest for both the scientific community and governmental institutions worldwide. The Campi Flegrei is an active volcanic area located west of the city of Naples, largely on the continental shelf of the Eastern Tyrrhenian margin that has been characterized by dominantly explosive eruptions during the latest Quaternary. This is one among …

Architecture of the NYT caldera and inner resurgent dome (Pozzuoli Bay, Campi Flegrei): new insights from seismic reflection and DInSAR data

2016

The Campi Flegrei and its offshore prolongation (Pozzuoli Bay) are a volcanic area dominated by a collapse caldera associated with the Neapolitan Yellow Tuff (NYT) eruption, occurred at ~15 ka BP, and by an intra-caldera resurgent dome. We present new insights into: a) the geometry and kinematics of faults formed inside and at the edge of the caldera, b) the architecture of the caldera and the resurgent dome, and c) the relationship between the structural elements of the caldera and ground deformation. This work is based on the integration of single- and multi- channel seismic, swath bathymetry data and ground deformation maps. The main results highlight that the NYT caldera, offshore, is c…