Rapid localized flank inflation and implications for potential slope instability at Tungurahua volcano, Ecuador

James Hickey*, Ryan Lloyd, Juliet Biggs, David Arnold, Patricia Mothes, Cyril Muller

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

1 Citation (Scopus)
45 Downloads (Pure)

Abstract

High rates of volcano surface deformation can be indicative of a forthcoming eruption, but can also relate to slope instability and possible flank collapse. Tungurahua volcano, Ecuador, has been persistently active since 1999 and has previously experienced catastrophic flank failures. During the ongoing eruptive activity, significant surface deformation has been observed, with the highest rates contained within the amphitheatre-shaped scar from the 3000-year-old failure on the west flank. However, the cause of this asymmetric deformation and how it might relate to slope stability has not been assessed. Here, for the first time, we present a range of models to test physical processes that might produce asymmetric deformation, which are then applied to slope stability. Our models are informed by InSAR measurements of a deformation episode in November 2015, which show a maximum displacement of ∼3.5 cm over a period of ∼3 weeks, during which time the volcano also experienced multiple explosions and heightened seismicity. Asymmetric flank material properties, from the rebuilding of the cone, cannot explain the full magnitude and spatial footprint of the observed west flank deformation. The inflation is inferred to be primarily caused by shallow, short-term, pre-eruptive magma storage that preferentially exploits the 3 ka flank collapse surface. Shallow and rapid pressurization from this inclined deformation source can generate shear stress along the collapse surface, which increases with greater volumes of magma. This may contribute to slope instability during future unrest episodes and promote flank failure, with general application to other volcanoes worldwide displaying asymmetric deformation patterns.

Original languageEnglish
Article number116104
Number of pages10
JournalEarth and Planetary Science Letters
Volume534
Early online date23 Jan 2020
DOIs
Publication statusPublished - 15 Mar 2020

Keywords

  • deformation
  • Finite Element Analysis
  • InSAR
  • slope stability
  • Tungurahua volcano

Fingerprint Dive into the research topics of 'Rapid localized flank inflation and implications for potential slope instability at Tungurahua volcano, Ecuador'. Together they form a unique fingerprint.

  • Cite this