Papers by Alessandro Bonforte
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
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This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
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Tectonophysics, 2020
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Remote Sensing, 2017
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Natural Hazards and Earth System Sciences Discussions, 2015
On 29 December 2013, the Chaparrastique volcano in El Salvador, close to the town of S. Miguel, e... more On 29 December 2013, the Chaparrastique volcano in El Salvador, close to the town of S. Miguel, erupted suddenly with explosive force, forming a more than 9 km high column and projecting ballistic projectiles as far as 3 km away. Pyroclastic Density Currents flowed to the north-northwest side of the volcano, while tephras were dispersed northwest and north-northeast. This sudden eruption prompted the local Ministry of Environment to request cooperation with Italian scientists in order to improve the monitoring of the volcano during this unrest. A joint force made up of an Italian team from the Istituto Nazionale di Geofisica e Vulcanologia and a local team from the Ministerio de Medio Ambiente y Recursos Naturales was organized to enhance the volcanological, geophysical and geochemical monitoring system to study the evolution of the phenomenon during the crisis. The joint team quickly installed a multi-parametric mobile network comprising seismic, geodetic and geochemical sensors, d...
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Mount Etna volcano is subject to transient magmatic intrusions and flank movement. The east flank... more Mount Etna volcano is subject to transient magmatic intrusions and flank movement. The east flank of the edifice, in particular, is moving eastward and is dissected by the Timpe Fault System. The relationship of this eastward motion with intrusions and tectonic fault motion, however, remains poorly constrained. Here we explore this relationship by using analogue experiments that are designed to simulate magmatic rift intrusion, flank movement, and fault activity before, during, and after a magmatic intrusion episode. Using particle image velocimetry allows for a precise temporal and spatial analysis of the development and activity of fault systems. The results show that the occurrence of rift intrusion episodes has a direct effect on fault activity. In such a situation, fault activity may occur or may be hindered, depending on the interplay of fault displacement and flank acceleration in response to dike intrusion. Our results demonstrate that a complex interplay may exist between an active tectonic fault system and magmatically induced flank instability. Episodes of magmatic intrusion change the intensity pattern of horizontal flank displacements and may hinder or activate associated faults. We further compare our results with the GPS data of the Mount Etna 2001 eruption and intrusion. We find that syneruptive displacement rates at the Timpe Fault System have differed from the preeruptive or posteruptive periods, which shows a good agreement of both the experimental and the GPS data. Therefore, understanding the flank instability and flank stability at Mount Etna requires consideration of both tectonic and magmatic forcing.
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Geophysical Monograph Series, 2000
The Sciara del Fuoco (SdF) landslides that occurred at the end of December 2002 prompted research... more The Sciara del Fuoco (SdF) landslides that occurred at the end of December 2002 prompted researchers to install geodetic networks to monitor deformations related to potential new slope failures. With this aim, an integrated multiparametric monitoring system was designed and deployed. In particular, this complex monitoring system is composed of four single systems: an electronic distance measurement network, installed immediately after the landslide events, a real-time GPS network, a ground-based interferometric linear synthetic ...
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High-resolution digital topography is essential for land management and
planning in any type of t... more High-resolution digital topography is essential for land management and
planning in any type of territory as well as the reproduction of the Earth
surface in a geocoded digital format that allows several Digital Earth
applications. In a volcanic environment, Digital Elevation Models are a
valid reference for multi-temporal analyses aimed to observe frequent
changes of a volcano edifice and for the relative detailed morphological
and structural analyses. For the first time, a DTM (Digital Terrain Model)
and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano
(Italy) derived from the same airborne Light Detection and Ranging
(LiDAR) are here presented. More than 250 million 3D LiDAR points have
been processed to distinguish ground elements from natural and
anthropic features. The end product is the highly accurate
representation of Mt. Etna landscape (DSM) and ground topography
(DTM) dated 2005. Both models have a high spatial resolution of 2 m
and cover an area of 620 km2. The DTM has been validated by GPS
ground control points. The vertical accuracy has been evaluated,
resulting in a root-mean-square-error of ± 0.24 m. The DTM is available
as electronic supplement and represents a valid support for various
scientific studies.
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FRINGE 2003 …, 2004
The July - August 2001 Mt Etna eruption has been studied using the DinSAR technique and monitored... more The July - August 2001 Mt Etna eruption has been studied using the DinSAR technique and monitored through both continuous GPS measurements on a network of permanent and static stations, as well as daily static and kinematic GPS measurements, made by INGV-CT, on ...
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ABSTRACT The Trecastagni Fault (TF) is a discontinuity that develops in the southern flank of Mt.... more ABSTRACT The Trecastagni Fault (TF) is a discontinuity that develops in the southern flank of Mt. Etna, between the Trecastagni and San Giovanni la Punta villages. This is an active structure with an approximately NNW-SSE trend characterized by continuous dynamics of normal and right-lateral type with intermittent accelerations, producing morphological escarpments and very shallow seismicity. The effects of the activity of the TF (creep) are visible on much of the provincial road 8/III and buildings. The fault has an important role in the instability affecting Mt. Etna's south-eastern flank and represents part of the southern boundary of the unstable sector. The seismicity of the TF is characterized by very shallow earthquakes with typical focal depths of 1-2 km. Evident co-seismic surface faulting occurred along the fault scarp in September 1980 and in November 1988. The motion of the fault between 2005-2011 been analyzed by using a multi-disciplinary approach involving terrestrial and satellite ground deformation data. At present, the systems that are able to investigate the fault of Trecastagni in detail are the extensometers installed in 2005, the levelling network installed in 2009 and InSAR remote sensing techniques. Levelling, InSAR and seismicity suggest that the activity of the TF should be related to the dragging effect of the sliding dynamics of the south-eastern flank of the volcano. The fault decouples a faster and south-eastwards moving block at east (hangingwall) from a slower and south-south-eastwards moving one at West (footwall). Two episodes of acceleration were recorded at the end of 2009 and during 2010. Data evidences that the acceleration episodes affected only portions of the fault and that stress may be accumulated and be periodically released. Acceleration of the eastern flank (to which the episodes of 2009 and 2010 seem to be related), can increase the stress accumulation inducing a seismic rupture on the fault; reservoir inflation and dyke intrusion seems to be a secondary cause of the TF accumulation and its release process.
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Journal of Volcanology and Geothermal Research, 2013
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Tectonophysics, 2015
ABSTRACT A geologic and geodetic integrated analysis of the northern margin of the Hyblean Platea... more ABSTRACT A geologic and geodetic integrated analysis of the northern margin of the Hyblean Plateau (SE Sicily) has been carried out in order to test the relationship between the active deformation, recorded by GPS data, and the long-term tectonic evolution, reconstructed by the interpretation of structural and morphological data. Our study revealed the active growth of a large antiform, as a consequence of the positive tectonic inversion of the previous flexure, bordering the Hyblean Foreland. The deformation of Middle-Late Pleistocene marine terraces and the evolution of the drainage system are consistent with a progressive regional tilting of the entire eastern sector of the Hyblean Plateau (Siracusa Domain), representing the southern limb of the active antiform. The geometry of the Late Quaternary marine strandlines, compared with the results of analogue models, is compatible with the effects of the NW-ward propagation of a detachment fault at depth. The active deformation of the Hyblean region, coherent with the Nubia-Eurasia plate convergence, suggests to candidate the inverted tectonics at the northern border of the Hyblean Plateau as potential seismogenic sources of the area.
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A geologic and geodetic integrated analysis of the northern margin of the Hyblean Plateau (SE Sic... more A geologic and geodetic integrated analysis of the northern margin of the Hyblean Plateau (SE Sicily) has been carried out in order to test the relation of the active deformation, recorded by GPS data, and the long-term tectonic evolution, recorded by structural and morphological data, with potential seismogenic sources of the region, where high level (MCS I0 = X – XI) historical seismicity occurred. To date, seismotectonic models have alternatively related the main seismogenic sources to the incipient rifting that reactivated the Malta Escarpment in the Ionian off-shore or to the still active NW-SE trending Nubia-Eurasia convergence, that remobilized the northern tectonic boundary of the Hyblean Plateau. In this region, the new data reveal that the active deformation can be framed in the flexural tectonics developed during the late stages of the Nubia-Eurasia plate convergence. Geodetic and geological data provide a coherent kinematic picture that is compatible with the occurrence ...
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Bollettino- Societa Geologica Italiana
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Papers by Alessandro Bonforte
planning in any type of territory as well as the reproduction of the Earth
surface in a geocoded digital format that allows several Digital Earth
applications. In a volcanic environment, Digital Elevation Models are a
valid reference for multi-temporal analyses aimed to observe frequent
changes of a volcano edifice and for the relative detailed morphological
and structural analyses. For the first time, a DTM (Digital Terrain Model)
and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano
(Italy) derived from the same airborne Light Detection and Ranging
(LiDAR) are here presented. More than 250 million 3D LiDAR points have
been processed to distinguish ground elements from natural and
anthropic features. The end product is the highly accurate
representation of Mt. Etna landscape (DSM) and ground topography
(DTM) dated 2005. Both models have a high spatial resolution of 2 m
and cover an area of 620 km2. The DTM has been validated by GPS
ground control points. The vertical accuracy has been evaluated,
resulting in a root-mean-square-error of ± 0.24 m. The DTM is available
as electronic supplement and represents a valid support for various
scientific studies.
planning in any type of territory as well as the reproduction of the Earth
surface in a geocoded digital format that allows several Digital Earth
applications. In a volcanic environment, Digital Elevation Models are a
valid reference for multi-temporal analyses aimed to observe frequent
changes of a volcano edifice and for the relative detailed morphological
and structural analyses. For the first time, a DTM (Digital Terrain Model)
and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano
(Italy) derived from the same airborne Light Detection and Ranging
(LiDAR) are here presented. More than 250 million 3D LiDAR points have
been processed to distinguish ground elements from natural and
anthropic features. The end product is the highly accurate
representation of Mt. Etna landscape (DSM) and ground topography
(DTM) dated 2005. Both models have a high spatial resolution of 2 m
and cover an area of 620 km2. The DTM has been validated by GPS
ground control points. The vertical accuracy has been evaluated,
resulting in a root-mean-square-error of ± 0.24 m. The DTM is available
as electronic supplement and represents a valid support for various
scientific studies.
(Tyrrhenian Sea, Italy). It is the southernmost tip of the southern branch of the Y-shaped archipelago; in particular,
it is part of the bigger Lipari-Vulcano volcanic complex that comprises the two southernmost islands of the
archipelago. This branch of the archipelago is NNW-SSE oriented and represent the off-shore prolongation of
the Tindari-Letojanni tectonic lineament in the NE Sicily, splitting the Appennine chain on the west, from the
Calabrian arc on the East. N-S compression seems to affect the western side of this NNW-SSE lineament, while
extension affects the eastern one, with active volcanism and a NW dipping Benioff plane. Historic activity at Vulcano
has been characterized by frequent transitions from phereatomagmatic to minor magmatic activity. The last
eruption in 1888-90 was characterized by energetic explosive pulses and defines the so-called “vulcanian” type of
activity. Since then, volcanic activity has taken the form of fumarolic emanations of variable intensity and temperature,
mainly concentrated at “La Fossa” crater, with maximum temperatures ranging between 200 and 300
C; temperature increases and changes in the gas chemistry, were often observed. The most recent episode began
in the 80’s when fumarole temperature progressively increased to 690C in May 1993. Vulcano is active and this
favoured monitoring and research studies, in particular focussed on the most recent structures.
In the frame of DPC-INGV “V3” project, we investigate the dynamics of the island through ca. 40 years of ground
deformation and seismicity data collected by the discrete and continuous INGV monitoring networks. We considered
levelling, GPS, EDM, seismic and tilt data. EDM and levelling measurements began in the middle 1970s and
since the late 1990s the same EDM network has been surveyed by GPS.
By combining and comparing geodetic data and seismicity we are able to distinguish three different scales of
phenomena: the first one seems to be linked to the regional tectonics, with a general transpressive kinematics;
the second one affects the northern half of the island and could be related to the caldera dynamics; the third one
affects only the cone of La Fossa. Regional tectonic stress seems to play an important role in the transition of the
volcanic system from a phase of stability to a phase of unrest, inducing the heating and the expansion of shallow
hydrothermal fluids. Current local ground deformation at Vulcano may be linked to the geothermal system rather
than magmatic sources.
studies are usually performed. The non-uniqueness of the geophysical inverse models, the different level of resolution
and sensitivity of the results spurred us to integrate independent geophysical datasets and results collected
on Mt. Etna volcano, in order to obtain more accurate and reliable model interpretation.
Mt. Etna volcano is located along the eastern coast of Sicily and it is characterized by a complex structural setting.
In this region, the general N-S compressive regime related to the Africa – Europe collision interacts with the
WNW-ESE extensional regime associated to the Malta Escarpment dynamics, observable along the eastern coast
of Sicily.
At Mt Etna, a great number of studies concerns the existence of instability phenomena; a general eastward motion
of the eastern flank of the volcano has been measured with always increasing detail and its relationship with
the eruptive and magmatic activity is being investigated. The unstable flank appears bounded to the north by the
E–W-trending Provenzana - Pernicana Fault System and to the SW by the NS Ragalna Fault system. Eastwards,
this area is divided by several NW–SE trending faults. Recent studies consider this area as divided into several
blocks characterized by different shape and kinematics. Ground deformation studies (GPS and InSAR) define the
NE portion of the unstable flank as the most mobile one.
In the frame of the MEDiterranean Supersites Volcanoes (MED-SUV) project, ground deformation data (GPS and
INSAR), 3D seismicity, seismic tomography and two resistivity model profiles, have been analyzed together, in
order to put some constraints on the deep structure of the NE sector of the unstable flank.
Seismic data come from the permanent network run by the Istituto Nazionale di Geofisica e Vulcanologia (INGV)
- Sezione di Catania, Osservatorio Etneo.
Ground deformation data comes from InSAR Permanent Scatterers analyses of different spaceborn sensors.
The resistivity models come from a MT survey carried out on the eastern flank of the volcano and consisting of
thirty broad-band soundings along N-S and NW-SE oriented profiles.
We found that the NE sector of the sliding volume, modeled by ground deformation data inversions and characterized
by the highest displacement velocity, is characterized low resistivity values and it is bounded by two seismic
clusters. The northern one is clearly related to the Pernicana fault and it’s not deeper than 3 km b.s.l. while the
second one is located southwards, beneath the northern wall of the Valle del Bove, not related to any evident structure
at the surface. An evident layer with very reduced seismicity lies at 3 km of depth and well corresponds to the
simplified analytic models of a sliding planar surface resulting from GPS data inversions.
eruption, a large amount of magma was stored at depth. Until now, a joint inversion of displacement and gravity data
has not been performed. We carry out simultaneous inversion of gravity, GNSS and Advanced Differential InSAR
displacement data covering the 1995-2000 period. Our inversion scheme uses bodies with a 3D free geometry
to determine the best-fitting configuration of pressure and density sources. Results provide new insight into the
shallow plumbing system of Etna. Inflation pressure sources are located below the northwestern flank, at depths of
4-6 km, while a mass source is located in a shallower position below the SE flank. Mass increases and decreases
are observed without significant associated deformation. The neat separation between mass and pressure sources
is a key feature to understand the processes which controlled the activity of Mt Etna during the studied period.