Italy ponders volcanic threat from Ischia 28 April 2010

At the northern end of the Gulf of Naples in southern Italy lies the island of Ischia, a complex volcanic edifice with a long history of violent activity that last erupted in 1302 AD. It has a population of around 60,000 and is a popular tourist destination. Now the head of Italy’s civil protection service, Guido Bertolaso, is sounding alarm bells about the potential volcanic threat from Ischia in the Italian media (only a few weeks after his Istituto Nazionale di Geofisica e Vulcanologia counterpart Dr Enzo Boschi did the same thing over Mount Marsili).

During a press conference in which he discussed the range of volcanic risks faced by Italy, Bertolaso described Vesuvius ‘the biggest civil protection problem in our country’, but pointed the finger at Ischia as potentially the more immediate threat: ‘If I were to say what is potentially the volcano with a bullet in the chamber, I would say that it is not Vesuvius but the island of Ischia’. He said that since the eruption of 1302 the height of Mount Epomeo, the highest point of the island (which is a volcanic horst) has increased by 800 metres [EDIT, this should almost certainly be 300 metres, see comments below. FURTHER EDIT, the uplift is to ~780 metres a.s.l., but that's over the past 33,000 years - see note at the end of this post.] and that the magma chamber is ‘reloading’. However, whereas everybody knows that Vesuvius is an active volcano there is not the same perception of Ischia: this is clearly something that Bertolaso wants to change.

Bertolaso also discussed the need for better monitoring of active undersea volcanoes, and floated the idea of a Europe-wide volcanic ash monitoring network, in the wake of the disruption caused by Eyjafjallajökull.

(INGV’s monitoring page for Ischia is here. There is no sign of any impending eruption at Ischia, as Bertolaso made clear in his remarks.)

NOTE: Ischia uplift. Poli et al (1989) note that ‘the rapid uplift of the central horst of Mount Epomeo … from about -200 m to 700 m occurred after 33,000 y. B.P., mostly in the last 20,000 years’ (p. 332). Poli et al also anticipated that the main potential volcanic hazard at Ischia was landslides and mudflows consequent on this rapid uplift, rather than the direct effects of volcanic activity, with future eruptions likely to be effusive rather than explosive, although there remains the possibility of ‘phreatic or phreatomagmatic crisis’ (p. 334). S. Poli et al, ‘Time dimension in the geochemical approach and hazard estimates of a volcanic area: the Isle of Ischia case (Italy)’, Journal of Volcanology & Geothermal Research, 36 (1989), pp. 327-335 [doi:10.1016/0377-0273(89)90077-2].

News
Bertolaso: allarme eruzione a Ischia – Corriere della Sera, 27 April 2010
Bertolaso lancia l’allarme su Ischia ‘Un vulcano con il colpo in canna’ – La Repubblica, 27 April 2010
Vulcani: Bertolaso, parte il monitoraggio di quelli sommersi – AGI, 27 April 2010
Bertolaso propone sistema monitoraggio Ue per ceneri vulcaniche – Reuters, 27 April 2010
Ischia volcano eruption concerns – Press Association, 28 April 2010
Italy says Ischia volcano, near Naples, could blow – The Statesman, 28 April 2010

Information
Global Volcanism Program: Ischia – information about Ischia (0101-03=) from the GVP
Osservatorio Vesuviano: Ischia – Ischia monitoring information from the INGV’s Vesuvius Observatory