Regimes of magma recharge and their control on the eruptive behaviour during the period 2001–2005 at Mt. Etna volcano |
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Authors: | Carmelo Ferlito Marco Viccaro Eugenio Nicotra Renato Cristofolini |
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Institution: | 1.Dipartimento di Scienze Geologiche,Università di Catania,Catania,Italy |
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Abstract: | Mount Etna volcano (Italy) during the period 2001–2005 has undergone a period of intense eruptive activity marked by three
large eruptions (2001, 2002–2003 and 2004–2005). These eruptions encompassed diverse eruptive styles and regimes: from intensely
explosive, during 2001 and 2002–2003 eruptions, to exclusively effusive in the 2004–2005 event. In this work, we put forward
the idea that these three eruptions are the response of the progressive arrival into the uppermost segment of the open-conduit
system of a new magma, which was geochemically distinct in terms of trace element and Sr–Nd–Pb isotope signature from the
products previously emitted by the Etnean volcano. The magma migrated upwards mainly through a peripheral tectonic system,
which can be considered as eccentric in spite of its relative proximity to the main system. The ingress of the new magma and
its gradual displacement from the eccentric system into the uppermost sector of the open-conduit gave rise to different eruptive
behaviours. At the beginning, the ascent of the undegassed magma, able to exsolve a gas phase at depth, and its interaction
with closed-system magma reservoirs less than 10 km deep gave rise to the explosive events of 2001 and 2002–2003. Later, when
the same magma entered into the open-conduit system, it took part in the steady-state degassing and partially lost its volatile
load, leading to a totally effusive eruption during the 2004–2005 event. One further consideration highlighted here is that
in 2001–2005, migration of the feeding axis from an eccentric and peripheral position towards the main open-conduit has led
to the development of a new vent (South East Crater 2) located at the eastern base of the South East Crater through which
most of the subsequent Etnean activity occurred. |
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