Evolution of deformation and stress changes during the caldera collapse and dyking at Bárdarbunga, 2014–2015: Implication for triggering of seismicity at nearby Tungnafellsjökull volcano

Abstract

Tungnafellsjškull; stress triggering; subsurface fault mapping. 47

Icecap and Subglacial Crustal Deformation Inferred From SAR Pixel Tracking: The 2014 Dike Intrusion Episode in the Bárðarbunga Volcanic System, Iceland

“…The direction of the horizontal displacements is nearly consistent with that of tectonic stress. However, the observational data require some shearing along the dike, consistent with the focal mechanisms of earthquakes along the dike (Ágústsdóttir et al, ; Parks et al, ; Ruch et al, ; Sigmundsson et al, ).…”

“…The direction of the horizontal displacements is nearly consistent with that of tectonic stress. However, the observational data require some shearing along the dike, consistent with the focal mechanisms of earthquakes along the dike (Ágústsdóttir et al, 2016;Parks et al, 2017;Ruch et al, 2016;Sigmundsson et al, 2015). Ruch et al (2016) applied synthetic aperture radar (SAR) pixel tracking and inferred the temporal evolution of graben subsidence, where conventional interferometric SAR (InSAR) could not be used for signal detection.…”

“…Previous geodetic studies in the area have reported ground displacements associated with the dike intrusion. Satellite radar interferograms and Global Navigation Satellite System (GNSS) measurements revealed displacements in a WNW‐ESE direction in the area north of the Vatnajökull icecap, caused by the dike intrusion, and the collapse of the subglacial Bárðarbunga caldera (Parks et al, ; Riel et al, ; Ruch et al, ; Sigmundsson et al, ). The direction of the horizontal displacements is nearly consistent with that of tectonic stress.…”

Physically Consistent Modeling of Dike‐Induced Deformation and Seismicity: Application to the 2014 Bárðarbunga Dike, Iceland

“…To compute predicted displacements, three parameters are required in addition to those listed in Table : , the volume change of a Mogi source representing caldera deflation at a fixed location (from Parks et al, ), from equation , and the dike length. The time span of the interferograms varies considerably with the later acquisition times ranging from 26 August to 20 September, 2014.…”

“…However, at this stage we treat as constant. Although this does not accurately capture the complicated near‐field deformation, which was a combination of a caldera collapse and a deeper depressurization (Parks et al, ), it should approximately correct for the far‐field displacement from the deeper depressurization.…”