Using satellite radar amplitude imaging for monitoring syn-eruptive changes in surface morphology at an ice-capped stratovolcano

D. W.D. Arnold*, J. Biggs, G. Wadge, P. Mothes

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

9 Citations (Scopus)
191 Downloads (Pure)

Abstract

Satellite-based measurements of synthetic aperture radar amplitude provide a method for monitoring volcanoes during unrest and eruptions even when visual observations are not possible, for example due to poor weather or at night, and when radar phase measurements are noisy or decorrelated. Here, we use high resolution radar amplitude images from the TerraSAR-X and COSMO SkyMed satellites to investigate surface changes associated with explosive eruptions of Cotopaxi volcano, Ecuador in August 2015. We generate change difference and amplitude ratio maps spanning the start of explosive activity at Cotopaxi, which show complex spatial variations in radar amplitude both on and around the summit ice-cap that we attribute to a number of processes related to the eruption. Observed amplitude decreases are caused by crater deepening, ashfall onto ice and surface smoothing by ashfall onto slopes facing away from the satellite, while amplitude increases are due to deposition of coarse lapilli and wet tephra, increased soil saturation due to geothermally driven glacier melting, and smoothing of slopes facing towards the satellite. We discuss the potential applications of radar amplitude images for monitoring and hazard evaluation at active volcanoes.

Original languageEnglish
Pages (from-to)480-488
Number of pages9
JournalRemote Sensing of Environment
Volume209
Early online date19 Mar 2018
DOIs
Publication statusPublished - 1 May 2018

Keywords

  • Explosive volcanism
  • Radar amplitude
  • SAR

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