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The Effects of Stratocone Morphology on Shallow Magma Transport

Kathryn Scholz1 , Meredith Townsend2, Andrew Harp3

  • Affiliations: 1 Department of Earth Sciences, University of Oregon, Eugene, USA; 2 Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, USA; 3 Department of Earth and Environmental Sciences, California State University Chico, Chico, USA 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 92

  • Programme No: 3.16.19

  • Theme 3 > Session 16

Abstract

Eruptive vent locations at stratovolcanoes, whether at the summit or on the flanks, are determined by the trajectories of dikes as magma ascends to the surface. Previous field studies and analog modeling (e.g., Acocella and Neri, 2009; Harp, 2021; Kervyn et al., 2009; Poland et al., 2008) have contributed considerably to this topic by highlighting how edifices provide a structural control on shallow magma transport. However, understanding the trajectory of dikes within a volcanic edifice is challenging due to the complexity of near-surface stress fields, especially given the large-scale topography of stratovolcanoes. Existing models for crustal stress in volcanic systems are either limited to basement rocks beneath the edifice (Pinel and Jaupart, 2000) or limited to simple topographic features that fail to capture the geometries of stratovolcanoes including breaks in slope and high aspect ratios (height to basal radius). Using a finite element approach, we compute the state of stress in both the volcanic edifice and the underlying crust for a range of edifice morphologies representative of arc volcanoes worldwide. These crustal stress models serve as a basis to examine how edifice morphology modulates shallow magma transport at stratovolcanoes. This work provides a step towards understanding the structural controls on vent elevation at stratovolcanoes.