A summary lecture on two long-lived eruptions, and how we as scientists might respond to such events

1. Montserrat

Erupted volumes at Montserrat,

Pyroclastic flow development at Montserrat,

25 June 1997 block and ash flow deposits and surge deposits

Cyclic tilt patterns and seismicity, May 1997 Radial to dome Tangential to dome tilt quakes

Model for explosive eruptions at Montserrat in 1997 (accompanied by cyclic tilt and earthquake cycles)

Event tree probability at Montserrat,

2. Bárðarbunga 2014

Courtesy Nordic Volcanological Institute Bárðarbunga

Courtesy Nature

caldera Courtesy NASA Earth Observatory

Eruption site

Seismicity

Courtesy Icelandic Met Office

1 Sept 1 Oct1 Nov START OF CRISIS, 16 AUG 2014 Caldera quakes - cumulative energy released CALDERA QUAKES START

1 Sept15 Sept Cumulative energy, August – September 2014

Caldera earthquake magnitudes vs. depth

1 Sept 1 Oct1 Nov Caldera earthquake magnitudes vs. time Note intensification

Caldera earthquake locations

Deformation

Courtesy Icelandic Met Office Early-stage caldera subsidence until 8 September 2014

See next slide Courtesy Icelandic Met Office Caldera subsidence, 12 September – 8 November 2014

Courtesy Institute of Earth Sciences, University of Iceland Details of the subsidence process, September 2014

Toda et al. 2002, Nature 419:58-61 Miyakejima volcano, Japan, Summer 2000

Toda et al. 2002, Nature 419:58-61 Geshi et al. 2002, Bull Volcanol 64:55-68 START CALDERA COLLAPSE STOPS

3. Response

Restless volcanoes Signals of volcanic unrest commonly ambiguous and difficult to interpret Especially true for long-quiescent volcanoes Sometimes short times between first appearance of unrest and main eruption Knowledge of eruptive history critical for helping forecast future eruptions

Volcanoes and people 1 People commonly have difficulty in dealing with uncertainties associated with volcanic unrest –Complacency and forgetfulness between crises –Denial and accusation during a crisis –Different people and groups may react differently to a particular crisis Great need for scientists to involve government at all levels

Volcanoes and people 2 The importance and role of hazard maps –For the public –For governments –For insurance Near Naples, Italy

Small vs large eruptions Small eruptions can cause BIG problems! (Nevado del Ruiz 1985) Loss of life – compare Katmai 1912 (big eruption, no lives lost) with Mont Pelée 1902 and Ruiz 1985 (small eruptions, massive loss of life)

Large volcanoes and eruptions Supervolcanoes – small vs big eruptions Campi Phlegrei, Italy Rabaul, Papua New Guinea Long Valley, California USA These volcanoes’ unrest characterized by (a) significant ground deformation and (b) high levels of seismicity

Long Valley unrest,

2012 Latest USGS GPS deformation data for Long Valley, 16 April 2012

The role of scientists Scientists need to explain their science to the public: –Presence of a volcano observatory critical –Inform people during non-crisis times The involvement of many scientists: -multiple teams potentially creating conflict, but… -the need for a hearing of diverse opinions

Monitoring approaches Simple vs. sophisticated Minimal monitoring for baseline data

Crack measurement on Mt St Helens

Aleutian monitoring Shishaldin-single seismometer Augustine-webcam

An informed approach to volcanic unrest Geologic history MonitoringPublic response

Thank you for your interest ! It has been a lot of fun for me teaching you this semester !