Evolution of a lateral dike intrusion revealed by relatively-relocated dike-induced earthquakes: The 2014–15 Bárðarbunga–Holuhraun rifting event, Iceland ...

• Main Authors: Woods, J, Winder, T, White, RS, Brandsdóttir, B
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2019
• Subjects: Bardarbunga; dike intrusion; microseismicity; cross-correlation; rifting; induced earthquakes; Holuhraun; Iceland
• Online Access: https://dx.doi.org/10.17863/cam.33723; https://www.repository.cam.ac.uk/handle/1810/286414

Understanding dikes is vital as they serve both as bodies that build the crust and as conduits that feed eruptions, and must be monitored to evaluate volcanic hazard. During the 2014-15 Bárðarbunga rifting event, Iceland, intenseseismicity accompanied the intrusion of a ∼ 50 km lateral dike which culminated in a 6 month long eruption. We here present relocations of earthquakes induced by the lateral dike intrusion, using cross-correlated, sub-sample relative travel times. The ∼ 100 m spatial resolution achieved reveals the complexity of the dike propagation pathway and dynamics (jerky, segmented), and allows us to address the precise relationship between the dike and seismicity, with direct implications for hazard monitoring. The spatio-temporal characteristics of the induced seismicity can be directly linked in the first instance to propagation of the tip and opening of the dike, and following this - after dike opening - indicate a relationship with magma pressure changes (i.e. dike inflation/deflation), ...