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Instituto de Investigação
em Vulcanologia e Avaliação de Riscos
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Painéis ► em encontros internacionais

 

Referência Bibliográfica


PACHECO J.M. (2004) - Faial Island volcanic history and its hazard implications (Azores). International Symposium “REDUCING VOLCANIC RISK IN ISLANDS”, Tenerife, Canary Islands, Spain, 2 - 6 de Junho (Poster).

Resumo


Faial Island was built up by four volcanic systems: (1) Ribeirinha Shield Volcano; (2) Faial Central Volcano; (3) Horta Basaltic Fissural System and (4) Capelo Basaltic Fissural System. In the last 6000 years, volcanic activity in the island was centred on Faial Central Volcano and Capelo Basaltic Fissural System, suggesting that those are the most probable sources of future eruptive events on Faial.
 
The Faial Central Volcano is the largest on the island. It had 9 explosive eruptions during the last 6000 years, with magnitudes up to about 4.5 and produced a width variety of pyroclastic deposits, including tephra fall deposits, surge deposits and pyroclastic flow deposits. One of the largest eruptions of the volcano’s recent history occurred at about 1000 years ago, when several pyroclastic flows and surges covered an important part of the island and a young caldera was formed.
 
The Capelo basaltic fissural system is the youngest volcanic system of the island and produced 2 eruptions in the last 300 years. Its activity has been characterised by moderate subaerial explosive to effusive basaltic (s.l.) eruptions and hydromagmatic surtseyan eruptions.
 
Considering the volcanic history of the island, the expected eruptive style on Faial is dependent on the geologic setting of the event. Therefore, a future event related with the Faial Central Volcano may produce either phreatic, phreatomagmatic or magmatic eruptions of subplinian/plinian type.
 
In the western sector of the island, dominated by the Capelo fissural system, a future event will probably be centred along the Capelo Fault, either on subaerial or submarine environment. Such an eruption would be of strombolian or hawaiian type, If subaerial, or surtseyan, if submarine.
 
In order to assess volcanic hazards in Faial island, several critical parameters where determined taking into consideration the maximum dispersal of each volcanic deposit.

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Anexos