The role of the NNW structural trend in the recent geodynamic evolution of north-eastern sicily and its volcanic implications in the etnean area

Giudice, E. Lo; Rasà, Riccardo

doi:10.1016/0264-3707(86)90012-8

Cited by 48 publications

(18 citation statements)

References 8 publications

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“…Spatial distributions of parasitic cones (Villari et al 1988a(Villari et al , 1988b, as well as recent lava flow patterns and fracture/dike orientations (Rasà et al 1996), suggest that volcanic activity is controlled mainly by the NNW±SSE and NE±SW systems. Based also on analyses of seismic activity, several authors (Lo Giudice et al 1982;Lo Giudice and Rasà 1986;Ferrucci and Patan 1993;Patan et al 1994;Cocina et al 1998) suspect that the NNW±SSE system may be a primary site of magma ascent in the crust, but this opinion is not shared by other investigators (Gresta et al 1990). …”

Section: Fault Systems and Volcanic Structuresmentioning

confidence: 96%

Volcanological inferences from seismic-strain tensor computations at Mt. Etna Volcano, Sicily

Barberi

Cocina

Neri

et al. 2000

Bulletin of Volcanology

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Kostrov's (1974) algorithm for seismic-strain tensor computations, in the version implemented by Wyss et al. (1992a) for error estimates, has been applied to shear-type earthquakes occurring beneath the Etna volcano during 1990±1996. Space±time variations of strain orientations and amplitudes have been examined jointly with ground-deformation and gravimetric data collected in the same period and reported in the literature. Taking also into account the information available from volcanological observations and structural geology, we propose a model assuming that hydraulic pressure by magma emplaced in nearly north±south vertical structures produces the E±W orientation of the maximum compressive strain found in the upper 10 km beneath the crater area. In contrast, regional tectonics deriving from the slow, north± south convergence between the African and European plates appear to play a dominant role in the generation of stress and strain fields at crustal depths deeper than 10 km below the volcano. According to our interpretation, the progressive ascent of magma through the upper crust prior to eruption produces the observed gravity changes, cone inflation and unusual seismic strain rate in the upper 10 km associated with a more sharply defined seismic deformation regime (i.e. very small confidence limits of the e 1 orientation).In agreement with this model, deflation revealed by ground-deformation data during the course of the major 1991±1993 eruption was accompanied by a practically nil level of shallow seismicity.

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Section: Fault Systems and Volcanic Structuresmentioning

confidence: 96%

Volcanological inferences from seismic-strain tensor computations at Mt. Etna Volcano, Sicily

Barberi

Cocina

Neri

et al. 2000

Bulletin of Volcanology

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“…Regional‐tectonic studies at Mount Etna [ Lo Giudice and Rasà , 1986, 1992; Adorni and Carveni , 1993; Monaco et al , 1995, 1997, 2005; Lanzafame et al , 1996; Gresta et al , 1997; Azzaro , 1999] show that, over a length of about 20 km along the eastern base of the volcano, all segments of the Timpe fault system (Figure 1), NNW‐SSE striking, exhibit evidence of sustained, dominant normal slip, at least from the Late Pleistocene. This is a result of ∼N100°E directed extension related to incipient rifting processes at a regional scale [ Tapponnier , 1977; Ellis and King , 1991; Continisio et al , 1997; Monaco et al , 1997].…”

Section: The 2002–2003 Eruptive Event In the Regional‐tectonic Contexmentioning

confidence: 99%

“…The kinematics of Mount Etna is characterized by a nearly continuous ESE seaward movement of the eastern sector of the volcano. The origin of these large displacements recorded in the eastern flank is still controversial [e.g., Lo Giudice and Rasà , 1986, 1992; Borgia et al , 1992; Borgia , 1994; Rust and Neri , 1996; Monaco et al , 1997; Bonforte and Puglisi , 2003, 2006; Patanè et al , 2005; Rust et al , 2005; Palano et al , 2008] but several authors agree that the Pernicana fault represents the northern boundary of the unstable sector (Figure 1). Geodetic data collected since 1997 [ Azzaro et al , 2001; Palano et al , 2006] have outlined that the Pernicana fault is characterized by a fairly stable left‐lateral strike slip, with an average rate of about 2.8 cm/yr.…”

Section: Displacements Along the Fault Systemsmentioning

confidence: 99%

Magma, faults, and gravitational loading at Mount Etna: The 2002–2003 eruptive period

et al. 2011

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[1] Mount Etna is characterized by a complex structural setting that influences its evolution. In order to understand how the interaction between dike-forming intrusions and faulting influences the kinematics of the volcanic edifice, we developed a numerical model. It takes account of the topography, the medium heterogeneities, the gravitational loading, and the most active crustal discontinuities. A parameterization of the apparent coefficient of friction, as a function of the depth, has been considered in the range from 0.01 to 0.5. The density values used, Young's modulus, and Poisson's ratio range from about 1700 to 3200 kg/m 3 , 8.5 to 140 GPa, and 0.15 to 0.35, respectively. The model was applied to the 2002-2003 Etna eruption. The resulting deformation pattern was in agreement with the data provided by the continuous GPS stations and the seismological knowledge, obtaining displacements up to 1 m. Some discrepancies between the recorded ground deformation field and the modeled displacements allowed us to make some hypotheses on the volcano-tectonic (e.g., for the Pernicana fault) or regional-tectonic origin (Acireale-S. Alfio fault system) of the crustal discontinuities. Moreover, our results suggested that the Pernicana fault is characterized by a very low apparent coefficient of friction, less than 0.1. Furthermore, we evaluated the contribution of the gravitational loading and found that it implies a variation of about 10% of the overall deformation pattern. Our results clearly showed that the weight of the volcanic edifice acts in opposition to the magmatic intrusions. Conversely, we found that the presence of medium heterogeneities may favor the eastern flank movements toward the SE and the spreading of the summit area, playing a fundamental role in ascending magma. Finally, we investigated the shallow sliding model and found that dike-forming intrusions produce negligible displacements, less than 1 mm, along the subhorizontal detachment surface. Therefore, the gravitational loading during dike-forming intrusions is not able to trigger sliding processes along this plane.

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“…The NNW-SSE trending fault zone, older than Mt. Etna, borders on the eastern margin of Sicily crossing the volcano and characterises the main eruptive trend (e.g., FRAZZETTA and VILLARI, 1981;LO GIUDICE and RASA`, 1986). The relationship of this regional trend with the regional tectonic setting, volcanological features and geophysical constraints is widely discussed in BONACCORSO et al (1996).…”

Section: Introductionmentioning

confidence: 99%

Intrusive Mechanisms at Mt. Etna Forerunning the July-August 2001 Eruption from Seismic and Ground Deformation Data

Bonaccorso

D’Amico

Mattia

et al. 2004

Pure appl. geophys.

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In this work we present seismological and ground deformation evidence for the phase preparing the July 18 to August 9, 2001 flank eruption at Etna. The analysis performed, through data from the permanent seismic and ground deformation networks, highlighted a strong relationship between seismic strain release at depth and surface deformation. This joint analysis provided strong constraints on the magma rising mechanisms. We show that in the last ten years, after the 1991-1993 eruption, an overall accumulation of tension has affected the volcano. Then we investigate the months preceding the 2001 eruption. In particular, we analyse the strong seismic swarm on April 20-24, 2001, comprising more than 200 events (M max = 3.6) with prevalent dextral shear fault mechanisms in the western flank. The swarm showed a ca. NE-SW earthquake alignment which, in agreement with previous cases, can be interpreted as the response of the medium to an intrusive process along the approximately NNW-SSE volcano-genetic trend. These mechanisms, leading to the

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The role of the NNW structural trend in the recent geodynamic evolution of north-eastern sicily and its volcanic implications in the etnean area

Cited by 48 publications

References 8 publications

Volcanological inferences from seismic-strain tensor computations at Mt. Etna Volcano, Sicily

Volcanological inferences from seismic-strain tensor computations at Mt. Etna Volcano, Sicily

Magma, faults, and gravitational loading at Mount Etna: The 2002–2003 eruptive period

Intrusive Mechanisms at Mt. Etna Forerunning the July-August 2001 Eruption from Seismic and Ground Deformation Data

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