Climate change as a driver of volcano lateral collapse. Presented by Bill McGuire at the "Perth II: Global Change and the World's Mountains" conference in Perth, Scotland in September 2010.

1. Climate change as a driver
of volcano lateral collapse
Bill McGuire1 & Rachel Lowe2
1Aon Benfield UCL Hazard Research Centre,
University College London
2Exeter Climate Systems, University of Exeter
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

2. Talk structure
• Volcano lateral collapse
• A volcanic response to
climate change
• The COLLAPSE
database
• Temporal variations in the
lateral collapse record
• Climate influences and
collapse mechanisms
• Future prospects
Eyjafjallajökull (Iceland) April 2010
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

3. Volcano lateral collapse
• Failure of volcanic edifice Mount St Helens
leading to debris avalanche
• Common, transitory feature of
lifecycles of long-lived
volcanoes of all types
• Frequency: ~ 20 a century
over last 500 years
• 20% of ca 1500 active
Holocene volcanoes show
evidence of collapse
Hawaii
• Occur at all scales up to > Hawaii
1000km3
• Collapse velocities typically >
40ms-1
• May be eruption-related
• Significant hazard
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

4. Factors affecting volcano stability
COLLAPSE TRIGGERS
Seismic ground acceleration
Pore-water pressurization
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

5. A Geospheric response to climate
change
• Periods of dynamic
climate change elicit
response from
Geosphere
– Increased seismicity
– Elevated levels of
submarine landslide
formation
• Volcanic response
– High latitude ice caps
(Iceland)
– Globally
Phil Trans. R. Soc. A., 368, 2010
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

6. The volcanic response
• Ice unloading at high •
latitudes (e.g. Iceland)
– Volcanic activity > x10
more frequent that current
during early post-glacial
times
– Mantle melt production
increased x30 Vatnajökull
• Global response
– ice-core record
– Ice melt; increased ppn;
sea-level rise
– Volcano lateral collapse
contribution?
Mount St Helens (1980)
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

7. Sea-level rise as a driver?
Increased volcanism
Eruption
Reduced compressive Maximum shear stress on
stress seaward flank Lateral collapse
Pumping action
Increased
compressive stress
Frequency of significant Mediterranean
eruptions between 15 and 8 thousand y BP =
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003with time averaged 1,050 y
350 y compared

8. The COLLAPSE database
480 Quaternary
collapse events
at 316 volcanoes The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

9. Spatial distribution of collapses
The information contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

10. Temporal distribution of lateral
collapses
The temporal distributionof lateral collapse events in the Quaternary
North Pole
The temporal distribution of lateral collapse events with volume 80
C-14 limit
10000
60
1000
100
40
10
Volume ( km3)
20
1
Latitude
Issues: preservation & dating 0.1
0
100 collapse events recognised in last 500y 0.01
- sample is a very small fraction of total 0.001
-20
0.0001
1000000 900000 800000 700000 600000 500000 400000 300000 200000 100000 0 -40
Age (years BP)
-60
-80
1800 1600 1400 1200 1000 800 600 400 200 0
South Pole
Age (ka BP)
The information contained in this document is strictly proprietary and confidential
Lateral Collapse Events
©Benfield Hazard Research Centre 2003

11. Filtered collapse record and
collapse rates
The temporal distribution of lateral collapse events by region
20 90
18
Collapses > 40 ka and < 2 ka and volumes < 1km3 filtered out
80
16
70
Distance from Equator (°N /°S)
Collapse rate (per 1000 years)
14
60
12
50
10
Rate of lateral collapse event in the marine and continental environment 40
8
14
30
6
12
29 percent collapse at island volcanoes 20
4
42 percent within 250km of coast
Collapse rate per 1000 years
10
2 10
8
0 0
Equator
6 40 35 30 25 20 15 10 5 0
Age (ka BP)
4
Africa Austalasia Canary Islands
Central America and the Caribbean Europe Hawaaiian Isalnds
2
Indian Ocean Southeast Asia Japan
0 North America Russia South America
40 38 36 34
Global collapse26 24 100020 18
32 30 28
rate per 22 years 16 14 12 10 8 6 4 2 0
The information contained in this document is strictly proprietary and confidential
Age (ka BP)
Marine Environment Continental Environment ©Benfield Hazard Research Centre 2003

12. Pattern of collapse minima
The temporal distribution of lateral collapse events by region
20 90
18 80
16
70
Distance from Equator (°N /°S)
Collapse rate (per 1000 years)
14
60
12
50
10
40
8
30
6
20
4
2 10
0 0
Equator
40 35 30 25 20 15 10 5 0
Age (ka BP)
Africa Austalasia Canary Islands
Central America and the Caribbean Europe Hawaaiian Isalnds
Indian Ocean
LGM Heinrich Y.Dryas 8.2 ka Cold, dry
Southeast Asia Japan
North America Russia South America
Global collapse rate per 1000 years The information
event intervals
H1 contained in this document is strictly proprietary and confidential
©Benfield Hazard Research Centre 2003

13. A working hypothesis
• No obvious link with absolute
sea-level or rate of rise
• Incidence of collapse
increases following end of
colder/drier episodes
– Debuttressing effect of ice
mass loss
– Meltwater production and
increased precipitation
• Raised water tables
– Increased potential for
magma-water interaction at
shallow depths
– Pore-water pressurization by
magma provides potential
trigger
The information contained in this document is strictly proprietary and confidential
P. Trans. R. Soc. A., 368, 2559-2577. 2010
©Benfield Hazard Research Centre 2003

14. Future candidates for collapse?
Ritter Island (PNG) 1888 Pico do Fogo (Cape Verde)
The information contained in this document is strictly proprietary and confidential
Stromboli (Italy) 2002 Cumbre Vieja (La Palma)
©Benfield Hazard Research Centre 2003