loading page

Ring Fault Slip Reversal at Bárðarbunga Volcano, Iceland: Seismicity during Caldera Collapse and Re-Inflation 2014-2018
  • +1
  • Esme Olivia Southern,
  • Tom Winder,
  • Robert Stephen White,
  • Bryndís Brandsdóttir
Esme Olivia Southern
Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Bullard Laboratories, Department of Earth Sciences, University of Cambridge

Corresponding Author:[email protected]

Author Profile
Tom Winder
University of Cambridge, University of Cambridge, University of Cambridge
Author Profile
Robert Stephen White
Bullard Laboratories, Bullard Laboratories, Bullard Laboratories
Author Profile
Bryndís Brandsdóttir
University of Iceland, University of Iceland, University of Iceland
Author Profile

Abstract

Microearthquakes reveal the kinematics of the Bárðarbunga caldera ring fault; both during the 2014-2015 volcanic rifting event and gradual caldera collapse, and its subsequent, ongoing re-inflation. Manual analysis of earthquake phase arrivals has been used to produce reliable hypocenter locations with tightly constrained focal mechanisms for events both during and after the eruption. Phase arrival polarities are reversed between events that occurred during the caldera collapse and those that have occurred since. Both precise relative relocations of the seismicity and focal mechanism solutions confirm that this is due to slip reversal on the same ring fault structure. The fault planes are steeply dipping (averaging 78 ± 6°). Furthermore, the spatial distribution of aftershocks following large-magnitude post-eruptive events provides constraints on the shape and size of the fault plane and the amount of slip that typically occurs in caldera events.