Volcano-Seismic (V-S) crises: The slow passage from quiescence to eruption

"When a potentially explosive volcano enters a period of crisis, interested scientists and a concerned, if not terrified local community are brought into what euphemistically might be called a challenging relationship" (Fiske, 1984).

If a V-S crisis accelerates rapidly, with corroborating precursors; then the decision to evacuate is a simple one to make and can be more a matter of time before the inevitable damage.

Not all volcanoes behave this way, Montserrat had several "false alarms" with V-S  crises in 1897, 1933, 1966, 1985, 1992 and then the crisis that spiralled to eruption in 1995. Unzen followed a similar pattern with a more linear decline in repose between V-S crises, as did Mt. Spurr in Alaska but so too did the Southern centres of Dominica where only a phreatic eruption followed. Some volcanoes have V-S crises that are isolated and do not lead to eruption (e.g. Tenerife 2004), so are they totally stochastic events unrelated to the eventual eruption or part of a gradual process of building overpressure or plug degradation?

The idea is to have a short presentation (15 minutes) looking at some of the slow awakening volcanoes and the V-S crises they have had and to review some of the deterministic tools available.

Then have a discussion on the following...

a) How easy is it to determine a V-S crisis is none critical? (e.g. Tenerife 2004, Montserrat 1966-7)

b) Can we afford to evacuate populations on a "just in case" basis? (e.g. Guadeloupe 1976/7, Campi Flegrei 1970's and 1980's)

c) Is expert elicitation the solution?

Some good background reading will include:

Fiske, R.S., 1984, Volcanologists, journalists, and the concerned local public: A tale of two crises in the eastern Caribbean: in Studies in Geophysics Explosive Volcanism: Inception, Evolution and Hazards , National Academy Press, Washington, p. 170-176.