The 2018 Mount Etna earthquake (Mw 4.9): Depicting a natural model of a composite fault system from coseismic surface breaks

Repeating earthquakes and ground deformation reveal the structure and triggering mechanisms of the Pernicana fault, Mt. Etna

Communications Earth & Environment ◽

10.1038/s43247-021-00188-6 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Andrea Cannata ◽

Adriana Iozzia ◽

Salvatore Alparone ◽

Alessandro Bonforte ◽

Flavio Cannavò ◽

...

Keyword(s):

Ground Deformation ◽

Mount Etna ◽

Fault System ◽

Magma Intrusion ◽

Repeating Earthquakes ◽

Low Degree ◽

Mt Etna ◽

Recurrence Intervals ◽

Triggering Mechanisms ◽

Repeating Earthquake

AbstractStructure and dynamics of fault systems can be investigated using repeating earthquakes as repeatable seismic sources, alongside ground deformation measurements. Here we utilise a dataset of repeating earthquakes which occurred between 2000 and 2019 along the transtensive Pernicana fault system on the northeast flank of Mount Etna, Italy, to investigate the fault structure, as well as the triggering mechanisms of the seismicity. By grouping the repeating earthquakes into families and integrating the seismic data with GPS measurements of ground deformation, we identify four distinct portions of the fault. Each portion shows a different behaviour in terms of seismicity, repeating earthquakes and ground deformation, which we attribute to structural differences including a segmentation of the fault plane at depth. The recurrence intervals of repeating earthquake families display a low degree of regularity which suggests an episodic triggering mechanism, such as magma intrusion, rather than displacement under a constant stress.

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Mount Etna and the 1971 eruption - Structural implications of the 1971 Mount Etna eruption

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1973.0027 ◽

1973 ◽

Vol 274 (1238) ◽

pp. 79-82 ◽

Cited By ~ 4

Keyword(s):

Fault Zone ◽

Lava Flows ◽

Mount Etna ◽

Fault System ◽

Persistent Activity ◽

Tectonic Fault ◽

Magma Column ◽

Mt Etna

The author believes the 1971 eruption has been triggered by an uprise of the magma column which had for several decades fed the persistent activity located in both the NE crater and in the central crater’s chasm. This uprise split open a set of en-echelon fissures first on the southern, then on the eastern upper slopes of Mt Etna. Degassing occurred at the uppermost part of the successive fissure systems, while the degassed lava flows poured out at the lowermost end. When the ENE tectonic fault-system came into operation and controlled the second half of the eruption, it led to the engulfment of the degassing vent and subsequently acted as an undergound channel through which the degassed lavas could flow freely until they poured out at the lower end of the fault zone. This fault zone follows one of the main tectonic trends which intersect below Mt Etna, the main other ones being oriented SW-NE and WSW—ENE.

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SEM study of quartz grains from recent sediments: Western Iraq

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017743x ◽

1990 ◽

Vol 48 (4) ◽

pp. 860-861

Author(s):

F. Al-Kufaishi

Keyword(s):

Factor Loading ◽

Fault System ◽

Clay Material ◽

Crustal Material ◽

Factor Analyses ◽

Five Factors ◽

Sem Study ◽

Recent Sediments ◽

Quartz Grains ◽

Positive Factor

Two localities (Al-Marij and Laik) were selected to investigate the type of Quartz Grains from crustal material formed by evaporation of waters discharged by springs in Hit area, western Iraq, Previous studies on the crustal material (1,2) showed that the water discharged by these springs are associated with Abu-Jir fault system which run parallel to the Euphrates river,Factor analyses of the crustal and soil materials (50 samples analysed for 16 variables)(2) showed five factors; the first factor includes SiO2, Al2O3 and TiO2 with positive factor loading, and CaO, L.O.I. with negative loading and hence lead to the conclusion that the distribution of these variables is a reflection of transported clay material.This study concentrates on the use of SEM to investigate the contribution of Quartz grains found in the crustal material on two selected sites.

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