A sagging-spreading continuum of large volcano structure
P.K. Byrne et al., Dept. of Terrestrial Magnetism, Carnegie Institution of Washington, 5240 Broad Branch Road NW, Washington, D.C. 20005, USA; and Laboratoire Magmas et Volcans, Universit Blaise-Pascal, 5 Rue Kessler, 63038 Clermont-Ferrand Cedex, France. Posted online 17 Jan. 2013; http://dx.doi.org/10.1130/G33990.1.
Gravity can cause large volcanoes to deform under their own weight. Such volcanoes can either spread outward along their underlying "basement" rocks, or they can sag downward into their basement. These deformation processes strongly affect the structural stability and eruptive behavior of the volcano. Using scaled "sand-box" simulations, P.K. Byrne and colleagues identify a continuum of deformation styles, from pure spreading to pure sagging. They explore how volcano-basement coupling and basement rigidity control the position of a given volcano along this continuum. For example, this study shows how a combination of spreading and sagging can explain many enigmatic features of Olympus Mons on Mars, the largest volcano in the Solar System. More broadly, their results can help volcano hazard studies by showing how spreading promotes, but sagging reduces, the risk of catastrophic landslides or sector collapses.
Isolation and characterizatio
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