The largest volcanic eruptions in the geologic record have no analogue
in the historical record. These eruptions had global impacts, but
are known only through their eruptive products. They have left behind
calderas that formed as the surface collapsed when eruption evacuated
magma chambers at 5-15 km depths. It is generally assumed that calderas
reflect the spatial dimensions of underlying magma reservoirs. Here
we use a numerical model of conduit flow and dynamic magma-chamber
drainage to show that caldera size can be affected by the material
properties of crystal-rich silicic magma. We find that magma in the
chamber can experience a rheological transition during eruption.
This transition causes magma near the conduit to behave as a fluid,
whereas magma farther away behaves elastically and remains locked.
The intervening surface-the yield surface-expands through the chamber
as eruption progresses. If a yielding transition occurs, calderas
can form before complete mobilization of the entire reservoir. The
resulting distribution of eruption volumes is then bimodal, as observed
in the geologic record. We suggest that the presence or absence of
a magma yield stress determines whether caldera size reflects the
true spatial extent of magma storage.
%0 Journal Article
%1 karlstrom_etal:2012
%A Karlstrom, Leif
%A Rudolph, Maxwell L.
%A Manga, Michael
%D 2012
%I Nature Publishing Group
%J Nature Geoscience
%K geophysics
%N 6
%P 402--405
%R 10.1038/ngeo1453
%T Caldera size modulated by the yield stress within a crystal-rich
magma reservoir
%U http://dx.doi.org/10.1038/ngeo1453
%V 5
%X The largest volcanic eruptions in the geologic record have no analogue
in the historical record. These eruptions had global impacts, but
are known only through their eruptive products. They have left behind
calderas that formed as the surface collapsed when eruption evacuated
magma chambers at 5-15 km depths. It is generally assumed that calderas
reflect the spatial dimensions of underlying magma reservoirs. Here
we use a numerical model of conduit flow and dynamic magma-chamber
drainage to show that caldera size can be affected by the material
properties of crystal-rich silicic magma. We find that magma in the
chamber can experience a rheological transition during eruption.
This transition causes magma near the conduit to behave as a fluid,
whereas magma farther away behaves elastically and remains locked.
The intervening surface-the yield surface-expands through the chamber
as eruption progresses. If a yielding transition occurs, calderas
can form before complete mobilization of the entire reservoir. The
resulting distribution of eruption volumes is then bimodal, as observed
in the geologic record. We suggest that the presence or absence of
a magma yield stress determines whether caldera size reflects the
true spatial extent of magma storage.
@article{karlstrom_etal:2012,
abstract = {The largest volcanic eruptions in the geologic record have no analogue
in the historical record. These eruptions had global impacts, but
are known only through their eruptive products. They have left behind
calderas that formed as the surface collapsed when eruption evacuated
magma chambers at 5-15 km depths. It is generally assumed that calderas
reflect the spatial dimensions of underlying magma reservoirs. Here
we use a numerical model of conduit flow and dynamic magma-chamber
drainage to show that caldera size can be affected by the material
properties of crystal-rich silicic magma. We find that magma in the
chamber can experience a rheological transition during eruption.
This transition causes magma near the conduit to behave as a fluid,
whereas magma farther away behaves elastically and remains locked.
The intervening surface-the yield surface-expands through the chamber
as eruption progresses. If a yielding transition occurs, calderas
can form before complete mobilization of the entire reservoir. The
resulting distribution of eruption volumes is then bimodal, as observed
in the geologic record. We suggest that the presence or absence of
a magma yield stress determines whether caldera size reflects the
true spatial extent of magma storage.},
added-at = {2012-09-01T13:08:21.000+0200},
author = {Karlstrom, Leif and Rudolph, Maxwell L. and Manga, Michael},
biburl = {https://www.bibsonomy.org/bibtex/262007f5ab25d445414ee29498f2baf61/nilsma},
day = 29,
doi = {10.1038/ngeo1453},
interhash = {ce118cb4bb12c7429e29fa04a22c153a},
intrahash = {62007f5ab25d445414ee29498f2baf61},
journal = {Nature Geoscience},
keywords = {geophysics},
month = jun,
number = 6,
pages = {402--405},
publisher = {Nature Publishing Group},
timestamp = {2021-02-09T13:27:55.000+0100},
title = {Caldera size modulated by the yield stress within a crystal-rich
magma reservoir},
url = {http://dx.doi.org/10.1038/ngeo1453},
volume = 5,
year = 2012
}