First study of fault trench stratigraphy at Mt. Etna volcano, Southern Italy: understanding Holocene surface faulting along the Moscarello fault

Azzaro, Raffaele; Bella, Domenico; Ferreli, Luca; Michetti, Alessandro Maria; Santagati, Federica Maria Chiara; Serva, Leonello; Vittori, E.

doi:10.1016/s0264-3707(99)00055-1

Cited by 32 publications

(13 citation statements)

References 20 publications

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“…The Malta Escarpment transfer zone, along which the Mt. Etna volcano is emplaced, is characterized by vertical slip‐rates of up to 2 mm/yr [ Azzaro et al , 2000]; its movement is related to the larger retreat of the subduction hinge in the Ionian Sea with respect to the Sicily mainland.…”

Section: Geodynamic and Geological Settingmentioning

confidence: 99%

A buried volcano in the Calabrian Arc (Italy) revealed by high‐resolution aeromagnetic data

et al. 2010

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[1] Aeromagnetic data collected between the Aeolian volcanoes (southern Tyrrhenian Sea) and the Calabrian Arc (Italy) highlight a WNW-ESE elongated positive magnetic anomaly centered on the Capo Vaticano morphological ridge (Tyrrhenian coast of Calabria), characterized by an apical, subcircular, flat surface. Results of forward and inverse modeling of the magnetic data show a 20 km long and 3-5 km wide magnetized body that extends from sea floor to about 3 km below sea level. The magnetic properties of this body are consistent with those of the medium to highly evolved volcanic rocks of the Aeolian Arc (i.e., dacites and rhyolites). In the Calabria mainland, widespread dacitic to rhyolitic pumices with calc-alkaline affinity of Pleistocene age (1-0.7 Ma) are exposed. The tephra falls are related to explosive activity and show a decreasing thickness from the Capo Vaticano area southeastward. The presence of lithics indicates a provenance from a source located not far from Capo Vaticano. The combined interpretation of the magnetic and available geological data reveal that (1) the Capo Vaticano WNW-ESE elongated positive magnetic anomaly is due to the occurrence of a WNW-ESE elongated sill; (2) such a sill represents the remnant of the plumbing system of a Pleistocene volcano that erupted explosively producing the pumice tephra exposed in Calabria; and (3) the volcanism is consistent with the Aeolian products, in terms of age, magnetic signature, and geochemical affinity of the erupted products,. The results indicate that such volcanism developed along seismically active faults transversal to the general trend of the Aeolian Arc and Calabria block, in an area where uplift is maximized (∼4 mm/yr). Such uplift could also be responsible for fragmentation of the upper crust and formation of transversal faults along which seismic activity and volcanism occur.

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Section: Geodynamic and Geological Settingmentioning

confidence: 99%

A buried volcano in the Calabrian Arc (Italy) revealed by high‐resolution aeromagnetic data

et al. 2010

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“…Conversely, the eastern flank of the volcano is crossed by several youngest NNW and NNE trending fault segments causing a sharp morphology in the topography and showing steep escarpments [Monaco et al, 1997]. Most of the faults affecting the eastern flank are highly seismogenic and generate shallow earthquakes as well as coseismic cracks in the soil and creep phenomena [Azzaro et al, 1998;Azzaro, 1999;Azzaro et al, 2000]. This system, locally called ''Timpe'' (Figure 1a), represents the northernmost prolongation of the Malta Escarpment ( Figure 1b) and forms a NNW -SSE trending system of parallel step faults of considerable length (8 -10 km), having vertical offsets up to 200 m, that down throw toward the sea.…”

Section: Local Geology and Structural Settingmentioning

confidence: 99%

Evidence for ground motion polarization on fault zones of Mount Etna volcano

et al. 2008

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[1] During local and regional earthquakes, an evident amplification of horizontal ground motion is observed at two seismological stations near the Tremestieri fault, on the southeastern flank of Mount Etna volcano. Rotated component spectral ratios show a narrow spectral peak around 4 Hz along a N40°E direction. A conventional polarization analysis using the eigenvectors of the covariance matrix confirms the very stable directional effect enhancing the approximately NE-SW elongation of the horizontal ground motion in the fault zone. The effect is evident during the entire seismogram and independent of source back azimuth as well as distance and depth of earthquakes. The same polarization is observed in ambient noise as well. This consistency allowed us to use microtremors for checking ground motion polarization along and across the Tremestieri fault zone with a high spatial resolution. The result is a stable polarization of horizontal motion in the entire area that can be observed in a broad frequency band. To check whether this ground motion property is recurrent and to understand a possible relationship with fault strike, faulting style, or orientation of fractures, ambient noise was recorded on other mapped faults of the Mount Etna area, the Moscarello, Acicatena, and Pernicana faults. The latter, in particular, is characterized by different strike and faulting style. A systematic tendency of ambient noise to be polarized is found in all of the faults. A picture emerges where normal faults of the eastern flank show an E-W to NE-SW polarization that changes on the Pernicana fault, which develops approximately E-W and is characterized by a prevailing NW-SE to N-S polarization. Directions of polarization were never parallel to the fault strike. Moreover, polarization persists too far away from the fault trace, excluding an effect limited to a narrow low-velocity zone hosted between harder wall rocks. Both these observations rule out an interpretation in terms of faulttrapped waves. The cause of observed polarizations will be the subject of future studies. However, the consistency with recent results of velocity anisotropy in a part of the investigated area suggests a possible role of attenuation anisotropy on horizontal amplitude variations versus azimuth.

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“…However, on the eastern side of the volcano, from the 15°E meridian, the stress field is more complicated and no unique tectonic setting is observed (Cocina et al ., 1997). In fact, on the eastern side of Mt Etna and eastern Sicily, extensional tectonics are documented (Azzaro et al . 2000).…”

Section: Geodynamic Setting Of Mt Etnamentioning

confidence: 99%

Why Mt Etna?

2001

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The Etna volcano is located in an apparently anomalous position on the hinge zone of the Apennines subduction and its Na‐alkaline geochemistry does not favour a magma source from the deep slab as indicated for the Aeolian K‐alkaline magmatism. The steeper dip of the regional foreland monocline at the front of the Apennines in the Ionian Sea than in Sicily, implies a larger rollback of the subduction hinge in the Ionian Sea. Moreover, the lengthening of the Apennines arc needs extension parallel to the arc. Therefore, the larger southeastward subduction rollback of the Ionian lithosphere with respect to the Hyblean plateau in Sicily, should kinematically produce right‐lateral transtension and a sort of vertical ‘slab window’ which might explain (i) the Plio‐Pleistocene alkaline magmatism of eastern Sicily (e.g. the Etna volcano) and (ii) the late Pliocene to present right lateral transtensional tectonics and seismicity of eastern Sicily. The area of transfer of different dip and rollback occurs along the inherited Mesozoic passive continental margin between Sicily and the oceanic Ionian Sea, i.e. the Malta escarpment.

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First study of fault trench stratigraphy at Mt. Etna volcano, Southern Italy: understanding Holocene surface faulting along the Moscarello fault

Cited by 32 publications

References 20 publications

A buried volcano in the Calabrian Arc (Italy) revealed by high‐resolution aeromagnetic data

A buried volcano in the Calabrian Arc (Italy) revealed by high‐resolution aeromagnetic data

Evidence for ground motion polarization on fault zones of Mount Etna volcano

Why Mt Etna?

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