Publication Date:
2017-06-16
Description:
Climate warming at the end of the last glaciation caused ice
caps on Icelandic volcanoes to retreat. Removal of surface ice
load is thought to have decreased pressures in the underlying
mantle, triggering decompression melting, enhanced magma
generation and increased volcanic activity1–3. Present-day
climate change could have the same effect, although there may
be a time lag of hundreds of years between magma generation
and eruption4,5. However, in addition to increased magma
generation, pressure changes associated with ice retreat
should also alter the capacity for storing magma within the
crust. Here we use a numerical model to evaluate the effect of
the current decrease in ice load on magma storage in the crust
at the Kverkfjöll volcanic system, located partially beneath
Iceland’s largest ice cap. We compare the model results with
radar and global positioning system measurements of surface
displacement and changes in crustal stress between 2007 and
2008, during the intrusion of a deep dyke at Upptyppingar.
We find that although the main component of stress recorded
during dyke intrusion relates to plate extension, another
component of stress is consistent with the stress field caused
by the retreating ice cap. We conclude that the retreating
ice cap led to enhanced capture of magma within the crust.
We suggest that ice-cap retreat can promote magma storage,
rather than eruption, at least in the short term.
Type:
Article
,
PeerReviewed
Format:
text
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