- Italy
- Stefano Branca (Catania, 1969) is a senior researcher at the National Institute of Geophysics and Volcanology (INGV) ... moreStefano Branca (Catania, 1969) is a senior researcher at the National Institute of Geophysics and Volcanology (INGV) and he is currently Director of the Osservatorio Etneo-INGV Catania. His research focuses on the geological and volcanological study of the prehistoric and historical eruptions of Etna, as well as on the historical-volcanological analysis of the impact of effusive eruptions on the population and territory. He is the author of over fifty publications in national and international journals and the Geological Map of Etna Volcano (2011) on a 1:50,000 scale.
He also undertakes research on the retrieval, cataloging and valorization of the iconographic and photographic heritage of Italian volcanoesedit
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Table 3: 14C dates of charcoals and bones came from the archeological sites of Etna region. Site Period Archaeological Facies material Sample code C 14 age BP 1σ cal BC 2σ cal BC References
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This study analyses the relationship between the pre-and protohistoric sites on the slopes of Etna and the volcanic products, as well as the diverse settlement strategies in the different periods of prehistory. New C14 dating from... more
This study analyses the relationship between the pre-and protohistoric sites on the slopes of Etna and the volcanic products, as well as the diverse settlement strategies in the different periods of prehistory. New C14 dating from significant excavations, in addition to those known from other Etnean sites, were performed with the aim of validating the chronology of the sequence of the different phases. A substantial concordance of the archaeological data with the volcanological ones has been found. It has been observed that a consistent human presence on Etna appears from the Middle Neolithic (5500 BC), after the sequence of eruptive events that marked the end of the Ellittico volcano (13550-13050 BC) and the formation of the Valle del Bove, and the subsequent debris and alluvial events on the eastern flanks of the volcano (7250-3350 BC). Human presence intensifies between the Late-Final Copper Age and the Early Bronze Age (2800-1450 BC), due to improvement in subsistence techniques and to the large presence of soils on lava flows suitable for sheep farming. The most recent phases of the Bronze Age are poorly represented, probably because of the concentration of the population in larger agglomerations (Montevergine and S. Paolillo at Catania, the Historical Hill at Paternò). The explosive eruptions taking place in this period seem to have had less impact on the settlement choices and have not affected the development of the sites over time.
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The 1971 eruption represents a benchmark in the recent history of Etna volcano. From a volcanological point of view, this eruption was characterised by complex intrusive dynamics associated with significant ground deformation that induced... more
The 1971 eruption represents a benchmark in the recent history of Etna volcano. From a volcanological point of view, this eruption was characterised by complex intrusive dynamics associated with significant ground deformation that induced the activation of the Moscarello seismogenic fault and the formation of a new summit crater: the Southeast Crater. At the same time, the 1971 event marks an important change in the eruptive style and composition of the magma towards products richer in K. It is no coincidence that, over the next fifty years, there would be an increase in the frequency of summit and flank eruptions and associated output rate. From an historical viewpoint, the eruptive event of 1971 was the first important flank eruption studied by the International Institute of Volcanology: the analysis of the scientific articles on this activity reveals a greater multidisciplinary content in the descriptions and explanations of volcanic activity. Particularly important were the collaborations of British and French research groups that, together with their Italian colleagues, succeeded in giving a complete picture of the eruption and describing the state of knowledge on the Sicilian volcano. The multidisciplinary methodology used to study this eruption is still valid today.
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The 1971 eruption represents a benchmark in the recent history of Etna volcano. From a volcanological point of view, this eruption was characterised by complex intrusive dynamics associated with significant ground deformation that induced... more
The 1971 eruption represents a benchmark in the recent history of Etna volcano. From a volcanological point of view, this eruption was characterised by complex intrusive dynamics associated with significant ground deformation that induced the activation of the Moscarello seismogenic fault and the formation of a new summit crater: the Southeast Crater. At the same time, the 1971 event marks an important change in the eruptive style and composition of the magma towards products richer in K. It is no coincidence that, over the next fifty years, there would be an increase in the frequency of summit and flank eruptions and associated output rate. From an historical viewpoint, the eruptive event of 1971 was the first important flank eruption studied by the International Institute of Volcanology: the analysis of the scientific articles on this activity reveals a greater multidisciplinary content in the descriptions and explanations of volcanic activity. Particularly important were the coll...
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This study analyses the relationship between the pre- and protohistoric sites on the slopes of Etna and the volcanic products, as well as the diverse settlement strategies in the different periods of prehistory. New C14 dating from... more
This study analyses the relationship between the pre- and protohistoric sites on the slopes of Etna and the volcanic products, as well as the diverse settlement strategies in the different periods of prehistory. New C14 dating from significant excavations, in addition to those known from other Etnean sites, were performed with the aim of validating the chronology of the sequence of the different phases. A substantial concordance of the archaeological data with the volcanological ones has been found. It has been observed that a consistent human presence on Etna appears from the Middle Neolithic (5500 BC), after the sequence of eruptive events that marked the end of the Ellittico volcano (13550 - 13050 BC) and the formation of the Valle del Bove, and the subsequent debris and alluvial events on the eastern flanks of the volcano (7250 - 3350 BC). Human presence intensifies between the Late-Final Copper Age and the Early Bronze Age (2800 - 1450 BC), due to improvement in subsistence ...
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The structure of an active volcano is highly dependent on the interplay between the geodynamic context, the tectonic assessment as well as the magmatic processes in the plumbing system. This complex scenario, widely explored at Etna... more
The structure of an active volcano is highly dependent on the interplay between the geodynamic context, the tectonic assessment as well as the magmatic processes in the plumbing system. This complex scenario, widely explored at Etna during the last 40 years, is nevertheless incomplete for the recent historical activity. In 1763 two eruptions occurred along the west flank of the volcano. There, an eruption started on 6th February and formed the scoria cone of Mt. Nuovo and a roughly 4-km-long lava flow field. Another small scoria cone, known as Mt. Mezza Luna, is not dated in historical sources. It is located just 1 km eastward of Mt. Nuovo and produced a 700 m long flow field. We focused on the activity of Mts. Nuovo and Mezza Luna for several reasons. First, the old geological maps and volcanological catalogues indicate that Mt. Mezza Luna and Mt. Nuovo cones were formed during the same eruption, while historical sources described Mt. Nuovo’s activity as producing a single scoria c...
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Analysis of the historical records of Etna’s eruptive activity for the past three centuries shows that, after the large 1669 eruption, a period of about 60 years of low-level activity followed. Starting from 1727, explosive activity... more
Analysis of the historical records of Etna’s eruptive activity for the past three centuries shows that, after the large 1669 eruption, a period of about 60 years of low-level activity followed. Starting from 1727, explosive activity (strombolian, lava fountaining and subplinian) at the summit crater increased exponentially to the present day. Since 1763, the frequency of flank eruptions also increased and this value remained high until 1960; afterward it further increased sharply. In fact, the number of summit and flank eruptions between 1961 and 2003 was four times greater than that of the pre-1960 period. This long-term trend of escalating activity rules out a pattern of cyclic behaviour of the volcano. We propose instead that the 1670 2003 period most likely characterises a single eruptive cycle which began after the large 1669 eruption and which is still continuing.
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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... more
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 o...
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ABSTRACT Recent geological studies performed at Etna allow reassessing the stratigraphic frame of the volcano where distinct evolutionary phases are defined. This stratigraphic reconstruction was chronologically constrained on the basis... more
ABSTRACT Recent geological studies performed at Etna allow reassessing the stratigraphic frame of the volcano where distinct evolutionary phases are defined. This stratigraphic reconstruction was chronologically constrained on the basis of a limited number of U–Th and K–Ar age determinations whose uncertainty margins are sometimes too wide. For this reason, we successfully adopted at Etna the 40Ar/39Ar technique that allowed obtaining more precise age determinations. The incremental heating technique also gives information on sample homogeneity, and potential problems of trapped argon. Five samples were collected from stratigraphically well-controlled volcanic units in order to chronologically define the transition between the fissure-type volcanism of the Timpe phase to the central volcanism of the Valle del Bove Centers. Isotopic ages with an uncertainty margin of 2–4% have been obtained emphasizing that this transition occurred (130–126 ka) without significant temporal hiatus.
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Research Interests: Geodesy, Geology, Geochemistry, Geophysics, Tectonics, and 3 moreSeismology, Kinematics, and Volcano
ABSTRACT Between January 2011 and April 2012, the Southeast Crater (SEC) on Mount Etna was the site of 25 episodes of lava fountaining, which led to the construction of a new pyroclastic cone on the eastern flank of the SEC. During these... more
ABSTRACT Between January 2011 and April 2012, the Southeast Crater (SEC) on Mount Etna was the site of 25 episodes of lava fountaining, which led to the construction of a new pyroclastic cone on the eastern flank of the SEC. During these episodes lava overflows reached 4.3 km in length with an area of 3.19 km2 and a volume of 28 × 106 m3. The new cone, informally called New Southeast Crater (NSEC), grew over a pre-existing subsidence depression (pit crater), which had been formed in 2007–2009. The evolution of the NSEC cone was documented from its start by repeated GPS surveys carried out both from a distance and on the cone itself, and by the acquisition of comparison photographs. These surveys reveal that after the cessation of the lava fountains in April 2012, the highest point of the NSEC stood 190 m above the pre-cone surface, while the cone volume was about 19 × 106 m3, representing 38% of the total (bulk) volume of the volcanic products including pyroclastic fallout erupted in 2011–2012, which is 50 × 106 m3 (about 33 × 106 m3 dense-rock equivalent). Growth of the new cone took place exclusively during the paroxysmal phases of the lava fountaining episodes, which were nearly always rather brief (on the average 2 h). Overall, the paroxysmal phases of all 25 episodes represent 51 h of lava fountaining activity—the time needed to build the cone. This is the fastest documented growth of a newborn volcanic cone both in terms of volumeand height. Mean effusion rates during the lava fountaining episodes on 20 August 2011 (E11), as well as 12 and 24 April 2012 (E24 and E25) exceeded 500 m3/s (with maximum rates of 980 m3/s during E11) and thus they are among the highest effusion rates ever recorded at Etna. The composition of the erupted products varies in time, reflecting different rates of magma supply into the shallowfeeding system, but without notable effects on the eruptive phenomenology. This implies that the dynamics leading to the episodic lava fountaining was largely, though not entirely, controlled by the repeated formation and collapse of a foam layer in the uppermost portion of the magmatic reservoir of the NSEC.
Research Interests: Geology, Geochemistry, Geophysics, Seismology, Subsidence, and 3 moreVolcano, Impact Crater, and Lava
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In the last years, paleomagnetism has been increasingly used to provide emplacement ages of loosely dated volcanics. Dating is achieved by comparison of paleomagnetic directions with a given reference curve of the paleosecular variation... more
In the last years, paleomagnetism has been increasingly used to provide emplacement ages of loosely dated volcanics. Dating is achieved by comparison of paleomagnetic directions with a given reference curve of the paleosecular variation (PSV) of the geomagnetic field. Recently, a debate has developed on the achievable precision (the α 95 value) of the paleomagnetic directions and hence on the accuracy that “paleomagnetic dating” can yield. At 39 different sites from Etna we paleomagnetically investigated 13 flows (four “test flows” ...
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... 1947 5/6 Feb NEC Lapilli and ash fall on the eastern flank to the coast. A continuous lapilli deposit with bombs up to 8 cm covered the Giarre area Cucuzza Silvestri 1949 1960 17 July CC This episode formed a several km-high eruptive... more
... 1947 5/6 Feb NEC Lapilli and ash fall on the eastern flank to the coast. A continuous lapilli deposit with bombs up to 8 cm covered the Giarre area Cucuzza Silvestri 1949 1960 17 July CC This episode formed a several km-high eruptive column. ...
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ABSTRACT The 1669 AD flank eruption was the most destructive event on Etna volcano in historical times (∼700 BC) and provided, because of the presence of numerous quarries and subsurface data, the opportunity for a unique case study in... more
ABSTRACT The 1669 AD flank eruption was the most destructive event on Etna volcano in historical times (∼700 BC) and provided, because of the presence of numerous quarries and subsurface data, the opportunity for a unique case study in which we directly measured the thickness of the lava field. Moreover, analysis of historical documents allowed reconstruction of the temporal evolution of the lava field and estimation of the average effusion rate. One hundred and thirty-eight thickness measurements, acquired from field surveys and subsurface data, allowed us to divide the lava field into 12 zones of homogenous mean thickness and to calculate a total lava volume of (607 ± 105) × 106 m3, corresponding to an average effusion rate of 58 ± 10 m3/s. This new volume differs by −24 % up to +64 %, from previously published values. The temporal evolution of the cumulative volume and average effusion rate were reconstructed for the first fourteen days, from field data and analysis of historical records. A short initial phase was characterized by a rapid increase in effusion rate, which reached a peak of ∼640 m3/s after 3 days. This was followed by a longer phase in which the flow rate decreased. The first 14 days were crucial for the development of the lava field, and in this time it covered 72 % of its final area and produced most of the damage. Thereafter, the growth of a complex lava tube network promoted lava field lengthening to the city of Catania, 17 km away from the vent. Effusion rate trends like those of the 1669 eruption can be adopted for future investigations aimed at assessing the effects of similar events on Etna’s most highly urbanized area and at other effusive basaltic volcanoes.
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The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is an Italian research institution with focus on earth sciences. Moreover, the INGV is the operational center for seismic surveillance and earthquake monitoring in Italy and is a... more
The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is an Italian research institution with focus on earth sciences. Moreover, the INGV is the operational center for seismic surveillance and earthquake monitoring in Italy and is a part of the civil protection system as a center of expertise on seismic, volcanic, and tsunami risks.INGV operates the Italian National Seismic Network and other networks at national scale and is a primary node of the European Integrated Data Archive for archiving and distributing strong-motion and weak-motion seismic recordings. In the control room in Rome, INGV staff performs seismic surveillance and tsunami warning services; in Catania and Naples, the control rooms are devoted to volcanic surveillance. Volcano monitoring includes locating earthquakes in the regions around the Sicilian (Etna, Eolian Islands, and Pantelleria) and the Campanian (Vesuvius, Campi Fregrei, and Ischia) active volcanoes. The tsunami warning is based on earthquake location...
Research Interests: Geology and Geophysics
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Mount Etna in Sicily (Italy) shows N 2500 years of interactions between volcanic eruptions and human activity, and these are well documented in historical sources. During the last 400 years, flank eruptions have had major impacts on the... more
Mount Etna in Sicily (Italy) shows N 2500 years of interactions between volcanic eruptions and human activity, and these are well documented in historical sources. During the last 400 years, flank eruptions have had major impacts on the urban fabric of the Etna region, especially in 1651–54, 1669, 1923 and 1928, and it is the last of these which is the focus of this paper. A detailed field and historical reconstruction of the 1928 eruption is presented which allows three themes to be discussed: the evolution of the flow field, lava volume and average magma discharge rate trend; the eruption's human impact, particularly the destruction of the town of Mascali; and the recovery of the region with reconstruction of Mascali in a new location. Detailed mapping of lava flows allowed the following dimensions to be calculated: total area, 4.38 × 10 6 m 2 ; maximum length, 9.4 km; volume , 52.91 ± 5.21 × 10 6 m 3 and an average effusion rate of 38.5 m 3 s −1. Time-averaged discharged rate...
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In this paper, we present new data from 226Ra–230Th dating and archaeomagnetism with the aim of improving the knowledge of the flank eruptions that occurred at Mt Etna during the Greek–Roman and Early Medieval periods, as defined in the... more
In this paper, we present new data from 226Ra–230Th dating and archaeomagnetism with the aim of improving the knowledge of the flank eruptions that occurred at Mt Etna during the Greek–Roman and Early Medieval periods, as defined in the new geological map of the volcano. The combination of the two dating techniques demonstrates that three major flank eruptions occurred on the lower north and west flanks during Greek–Roman epochs, producing large scoria cones and extensive lava flows. In particular, the Mt Ruvolo and Mt Minardo events highly impacted the territory of the west flank, notably by damming the Simeto River. The new data of the Millicucco and Due Monti lava flows, on the lower north–east flank, indicate a younger age than their stratigraphic ages quoted in the 2011 geological map, since they occurred around 700 and 500 AD, respectively. None of the large flank eruptions occurring on the lower slopes of Etna during the Early Medieval age are reported in the historical sources. Overall, our paper shows that a comprehensive assessment of eruptions at Mount Etna in the last three millennia can only be achieved through a multidisciplinary approach.
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The Alcantara Rivermarks the northern border of Etna volcano, and along its NE sector, it forms a narrowNW-SE elongated valley that is carved in the Mts. Peloritani sedimentary sequences. The valley has been invaded by several lava flows... more
The Alcantara Rivermarks the northern border of Etna volcano, and along its NE sector, it forms a narrowNW-SE elongated valley that is carved in the Mts. Peloritani sedimentary sequences. The valley has been invaded by several lava flows during the growth of the main bulk of the stratovolcano edifice in the past 60 ky (Ellittico and
Mongibello volcanoes). In this paper, we have constrained the age of the main lava flows forming the valley floor and reconstructed the length and volume of the main lava flow that impacted this area through a multidisciplinary approach integrating stratigraphic and aeromagnetic data analysis together with new paleomagnetic
and 14C dating. The new age determinations showed that the evolution of the present-day geological and hydrographic setting of the valleywasmainly conditioned by a fewflank eruptions that occurred in the lowerNflank of Etna during the activity of theMongibello volcano. In particular, between 13.9 and 9.7 ka BP the valley floor was
filled by the so-called Alcantara lava flow for its entire length up to the river mouth, reaching amaximumlength of about 24 km. Later, two other flank eruptions – producing the so-calledMt. Dolce and Solicchiata lava flows –
occurred at 9.1–7.2 and 7.3–7.2 ka BP (respectively), covering the eruptive fissure and the proximal portion of the Alcantara lava field and generated themost recent northward shift of the riverbed. Finally, 3Dmagneticmodeling
allowed us to calculate the total on- and off-shore volume of the Alcantara lava flow as 1 km3, a value comparable to those of the long-lasting historical eruptions of Etna. Conversely, the 24 kmlength reached by this lava flow is anomalously high when compared to lava flows of the past 15 ky, likely because its emplacement occurred
within the valley floor, preventing any possibility of lateral expansion.
Mongibello volcanoes). In this paper, we have constrained the age of the main lava flows forming the valley floor and reconstructed the length and volume of the main lava flow that impacted this area through a multidisciplinary approach integrating stratigraphic and aeromagnetic data analysis together with new paleomagnetic
and 14C dating. The new age determinations showed that the evolution of the present-day geological and hydrographic setting of the valleywasmainly conditioned by a fewflank eruptions that occurred in the lowerNflank of Etna during the activity of theMongibello volcano. In particular, between 13.9 and 9.7 ka BP the valley floor was
filled by the so-called Alcantara lava flow for its entire length up to the river mouth, reaching amaximumlength of about 24 km. Later, two other flank eruptions – producing the so-calledMt. Dolce and Solicchiata lava flows –
occurred at 9.1–7.2 and 7.3–7.2 ka BP (respectively), covering the eruptive fissure and the proximal portion of the Alcantara lava field and generated themost recent northward shift of the riverbed. Finally, 3Dmagneticmodeling
allowed us to calculate the total on- and off-shore volume of the Alcantara lava flow as 1 km3, a value comparable to those of the long-lasting historical eruptions of Etna. Conversely, the 24 kmlength reached by this lava flow is anomalously high when compared to lava flows of the past 15 ky, likely because its emplacement occurred
within the valley floor, preventing any possibility of lateral expansion.
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Volcanoes hold a fascination for human beings and, before they were recorded by literate observers, eruptions were portrayed in art, were recalled in legend and became incorporated into religious practices: being viewed as agents of... more
Volcanoes hold a fascination for human beings and, before they were recorded by literate observers, eruptions were portrayed in art, were recalled in legend and became incorporated into religious practices: being viewed as agents of punishment, bounty or intimidation depending upon their state of activity and the culture involved. In the Middle East the earliest record dates from the third millennium BCE and knowledge of volcanoes increased progressively over time. In the first century CE
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... of the volcanic edifice, namely the more densely urbanized areas, are described; volcanic elements such as eruptive fissures, caldera and ... Subsequently, the morphotectonic mapping has been compared with field data on geologic... more
... of the volcanic edifice, namely the more densely urbanized areas, are described; volcanic elements such as eruptive fissures, caldera and ... Subsequently, the morphotectonic mapping has been compared with field data on geologic marker offsets, as well as evidence of surface ...
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... During the second half of the twentieth century, S. Cucuzza Silvestri continued the chronology and, finally in June 1970, the International Insti-tute of ... A 3 km long lava flow eastward reached an A long lava flow field eastward... more
... During the second half of the twentieth century, S. Cucuzza Silvestri continued the chronology and, finally in June 1970, the International Insti-tute of ... A 3 km long lava flow eastward reached an A long lava flow field eastward reached an elevation of 160 m producing damage ...