TY - JOUR
T1 - Thoughts on the Criteria to Determine the Origin of Volcanic Unrest as Magmatic or Non-Magmatic
AU - Pritchard, M. E.
AU - Mather, T. A.
AU - McNutt, Stephen R.
AU - Delgado, F. J.
AU - Reath, K.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - As our ability to detect volcanic unrest improves, we are increasingly confronted with the question of whether the unrest has a magmatic origin (magma on the move) or a non-magmatic origin from a change in the hydrothermal system (fluids that are not magma on the move) or tectonic processes. The cause of unrest has critical implications for the potential eruptive hazard (e.g. used in constructing Bayesian Event Trees), but is frequently the subject of debate, even at well-studied systems. Here, we propose a set of multi-disciplinary observations and numerical models that could be used to evaluate conceptual models about the cause of unrest. These include measurements of gas fluxes and compositions and the isotopic signature of some components (e.g. H2, He, C, SO2, H2 O , CH4 and CO2), the spatial and temporal characteristics of ground deformation, thermal output, seismicity, changes in gravity, and whether there is topographic uplift or subsidence spanning hundreds to thousands of years. In several volcanic systems, both magmatic and non-magmatic unrest is occurring at the same time. While none of these observations or models is diagnostic on its own, we illustrate several examples where they have been used together to make a plausible conceptual model of one or more episodes of unrest and whether eruptions did or did not follow the unrest.
AB - As our ability to detect volcanic unrest improves, we are increasingly confronted with the question of whether the unrest has a magmatic origin (magma on the move) or a non-magmatic origin from a change in the hydrothermal system (fluids that are not magma on the move) or tectonic processes. The cause of unrest has critical implications for the potential eruptive hazard (e.g. used in constructing Bayesian Event Trees), but is frequently the subject of debate, even at well-studied systems. Here, we propose a set of multi-disciplinary observations and numerical models that could be used to evaluate conceptual models about the cause of unrest. These include measurements of gas fluxes and compositions and the isotopic signature of some components (e.g. H2, He, C, SO2, H2 O , CH4 and CO2), the spatial and temporal characteristics of ground deformation, thermal output, seismicity, changes in gravity, and whether there is topographic uplift or subsidence spanning hundreds to thousands of years. In several volcanic systems, both magmatic and non-magmatic unrest is occurring at the same time. While none of these observations or models is diagnostic on its own, we illustrate several examples where they have been used together to make a plausible conceptual model of one or more episodes of unrest and whether eruptions did or did not follow the unrest.
KW - volcano
KW - seismicity
KW - InSAR
UR - https://digitalcommons.usf.edu/geo_facpub/1426
UR - https://doi.org/10.1098/rsta.2018.0008
U2 - 10.1098/rsta.2018.0008
DO - 10.1098/rsta.2018.0008
M3 - Article
C2 - 30966934
VL - 377
JO - Philosophical Transactions of the Royal Society A
JF - Philosophical Transactions of the Royal Society A
ER -