Aon Benfield UCL Forecasting Volcanic Eruptions Hazard Centre · 3. Forecasting eruptions The...
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Forecasting Volcanic Eruptions Summary. Short-term forecasts of eruptions are crucial for protecting lives and property at active volcanoes. They are essential also for mitigating the impact of eruptions on critical transport facilities, including international aviation routes. Through theoretical analyses and new studies of the crust beneath volcanoes, the ABUHC is developing and implementing models for reliable eruption forecasts. 1. Pathway to an eruption High-impact eruptions normally occur at volcanoes that have been quiet for several generations (below, left). When such volcanoes reawaken, they must break open a new pathway through the Earth’s crust before magma can escape at the surface. The ABUHC is leading two research themes for investigating how the crust breaks beneath volcanoes: developing new models to interpret combined rates of stretching and fracturing – as monitored by deformation of the ground and by local seismicity; and using deep drilling through a volcano to investigate the detailed structure of the crust. 3. Forecasting eruptions The forecasting models perform well against test data from previous eruptions, such as the 1995 reawakening of Soufriere Hills, on Montserrat, for the first time in 350 years (above, left). On 22 September 2011, the ABUHC used the new model to warn that a volcanic eruption could occur during the first fortnight of October at El Hierro (above), the most westerly of the Canary Islands. The island had previously been quiet for at least 200 years. On 10 October, a submarine eruption began off the south coast of the island (above, inset). 2. Precursors to eruptions Increasing pressure in an underground body of magma causes the overlying crust to distort and to break. Changing rates of distortion and fracturing are thus key signals to monitor before eruptions. Distortion and fracturing are distributed unevenly because of local variations in the crust’s mechanical properties. We have combined conventional analyses of how intact rock deforms (e.g., elastic behaviour) with a new model that describes how quantum processes determine the probability of local fracturing. The results yield preferred combinations of changing rates of deformation and of earthquake occurrence from days to years before an eruption. More information? Contact: Christopher Kilburn ([email protected]). Aon Benfield UCL Hazard Centre, University College London, Gower Street, London WC1E 6BT, UK 1430s Changing elevation of columns at Serapis Capri N Campi Flegrei Naples Vesuvius Chaiten, Chile, 2008. First eruption for c. 9,500 years. (Photo: UPI.) 4. Drilling into volcanoes Campi Flegrei is a densely-populated volcanic complex that covers 200 km 2 west of Naples in southern Italy (above). It has experienced alternating periods of subsidence and uplift for at least 2,200 years (left). ABUHC studies have related the behaviour to long-term subsidence being interrupted occasionally by uplift due to the intrusion of magma about 2.5-3.0 km beneath the surface. The complex has recently been undergoing the first episode of net uplift to have occurred since its last eruption in 1538. An urgent question is whether Campi Flegrei is again preparing to erupt. The potential for magma to erupt is controlled by structures evolving in the crust during uplift. The ABUHC is a lead partner in the Campi Flegrei Deep Drilling Project, which will drill boreholes to depths of 3.5-4.0 km during 2012-13 (above and right). The borehole data will be used to simulate patterns of crustal uplift and, combined with our models of eruption precursors, will yield enhanced procedures for forecasting the next eruption. 0 400 800 1200 1600 1 6 11 16 Time (Days after 31 Oct 1995) Earthquakes per Day (day -1 ) Soufriere Hills, Montserrat Peak Rate, DN/dt = A exp [B(S 2 /YS*)N] ERUPTION 2002 Further Reading. (1) Forecasting eruptions: Kilburn CRJ (2012) J Geophys Res, 117, doi:10.1029/2011JB008703 (2) Campi Flegrei: Woo JYL, Kilburn CRJ (2010) J Geophys Res, 115, doi:10.1029/2009JB006913. Helping the vulnerable protect themselves Aon Benfield UCL Hazard Centre
Transcript of Aon Benfield UCL Forecasting Volcanic Eruptions Hazard Centre · 3. Forecasting eruptions The...
Forecasting Volcanic Eruptions
Summary. Short-term forecasts of eruptions are crucial for protecting lives and property at active volcanoes. They are essential also for mitigating the impact of eruptions on critical transport facilities, including international aviation routes. Through theoretical analyses and new studies of the crust beneath volcanoes, the ABUHC is developing and implementing models for reliable eruption forecasts.
1. Pathway to an eruption
High-impact eruptions normally occur at volcanoes that have been quiet for several generations (below, left). When such volcanoes reawaken, they must break open a new pathway through the Earth’s crust before magma can escape at the surface. The ABUHC is leading two research themes for investigating how the crust breaks beneath volcanoes: developing new models to interpret combined rates of stretching and fracturing – as monitored by deformation of the ground and by local seismicity; and using deep drilling through a volcano to investigate the detailed structure of the crust.
3. Forecasting eruptions
The forecasting models perform well against test data from previous eruptions, such as the 1995 reawakening of Soufriere Hills, on Montserrat, for the first time in 350 years (above, left).
On 22 September 2011, the ABUHC used the new model to warn that a volcanic eruption could occur during the first fortnight of October at El Hierro(above), the most westerly of the Canary Islands. The island had previously been quiet for at least 200 years. On 10 October, a submarine eruption began off the south coast of the island (above, inset).
2. Precursors to eruptions
Increasing pressure in an underground body of magma causes the overlying crust to distort and to break. Changing rates of distortion and fracturing are thus key signals to monitor before eruptions.
Distortion and fracturing are distributed unevenly because of local variations in the crust’s mechanical properties. We have combined conventional analyses of how intact rock deforms (e.g., elastic behaviour) with a new model that describes how quantum processes determine the probability of local fracturing. The results yield preferred combinations of changing rates of deformation and of earthquake occurrence from days to years before an eruption.
More information?Contact: Christopher Kilburn ([email protected]).
Aon Benfield UCL Hazard Centre, University College London, Gower Street, London WC1E 6BT, UK
1430s
Changing elevation of columns at Serapis
Capri
NCampi Flegrei Naples Vesuvius
Chaiten, Chile, 2008. First eruption for c. 9,500 years. (Photo: UPI.)
4. Drilling into volcanoes
Campi Flegrei is a densely-populated volcanic complex that covers 200 km2 west of Naples in southern Italy (above). It has experienced alternating periods of subsidence and uplift for at least 2,200 years (left). ABUHC studies have related the behaviour to long-term subsidence being interrupted occasionally by uplift due to the intrusion of magma about 2.5-3.0 km beneath the surface. The complex has recently been undergoing the first episode of net uplift to have occurred since its last eruption in 1538. An urgent question is whether Campi Flegrei is again preparing to erupt.
The potential for magma to erupt is controlled by structures evolving in the crust during uplift. The ABUHC is a lead partner in the Campi FlegreiDeep Drilling Project, which will drill boreholes to depths of 3.5-4.0 km during 2012-13 (above and right). The borehole data will be used to simulate patterns of crustal uplift and, combined with our models of eruption precursors, will yield enhanced procedures for forecasting the next eruption.
0
400
800
1200
1600
1 6 11 16
Time (Days after 31 Oct 1995)
Eart
hqua
kes
per
Day
(day
-1)
Soufriere Hills, MontserratPeak Rate, DN/dt = A exp [B(S2/YS*)N]
ERU
PTIO
N
2002
Further Reading. (1) Forecasting eruptions: Kilburn CRJ (2012) J Geophys Res, 117, doi:10.1029/2011JB008703 (2) Campi Flegrei: Woo JYL, Kilburn CRJ (2010) J Geophys Res, 115, doi:10.1029/2009JB006913.
Helping the vulnerable protect themselves
Aon Benfield UCL
Hazard Centre
