Abstract

The Morphotectonic Map of Mt. Etna (see attached table) is based on detailed field survey of morphologic and structural features outcropping on the volcanic edifice, supported by detailed analysis of orthophotos, stereo-pair photographs and satellite images. It helps to define more completely and accurately than previously done the structural network of active features that characterizes the volcanic edifice, and the relationships between faulting, fissuring and dyke swarms. Morpho-structural data are drawn on a schematic geological map where the main sedimentary and volcanic units have been reported. Morphotectonic analysis shows that Mt. Etna volcano exhibits active extensional features represented by normal faults and eruptive fissures which are related to shallow low-energy seismicity. These accommodate WNW-ESE striking extension, deduced from structural analysis and seismological data, related to incipient rifting processes at regional scale. The fault segments generally control the present topography and show steep escarpments with very young, mostly Late Pleistocene to Holocene, morphology. The most important structures are located along the eastern base of the volcano (Timpe fault system), where NNW-SSE striking normal faults with dextral-oblique component of motion represent the northern end of the Malta Escarpment system. In the north-eastern slope of the volcano these fault system swings to a NE trend which it keeps northwards along the Ionian Coast to Taormina and as far as Messina Straits. The major fissural eruptions occur along well defined, feeder-dykes and spatter cones belts that cut the upper slopes of the volcano, on the footwall of the Timpe fault system. They form NE trending pure extensional swarms along the NE sector of the volcano and en-échelon systems of N-S to NNE-SSW oriented fractures along NNW-SSE trending oblique-dextral shear-zones in the southern and south-eastern slopes. Such summital eruptive fissuring appears to result from the same ESE-striking regional extensional stress that drives active faulting at the base of the volcano suggesting a common tectonic origin.

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