The dynamics of fissure-fed eruptions: insights from the Svartsengi Volcanic System, Iceland

Thesis

Recent eruptions of the Svartsengi Volcanic System have repeatedly impacted infrastructure on the Reykjanes Peninsula, including damaging homes, affecting hot water supply, and displacing the entire town of Grindavík. As eruptions on the Reykjanes Peninsula are expected to continue for centuries, understanding their dynamics is crucial. This study analyses webcam footage from the first six eruptions of the Svartsengi Volcanic System to map fissure propagation and measure fire fountain heights over time. Later eruptions have been excluded due to the discontinuation of the webcam network. Results show that pulses of accelerated fissure propagation are driven by magma pressurisation, while variations in propagation speed along individual segments are influenced by crustal heterogeneities. Fissure locations are heavily affected by topography, including features formed during previous eruptions. Fire fountain heights are primarily influenced by fissure segment length and conduit erosion, with larger conduits increasing mass eruption rates and fountain heights. Predictive models successfully estimated fissure length and total erupted volume for the seventh eruption of the Svartsengi volcanic system based on pre-eruptive inflation duration, demonstrating the potential for forecasting eruption characteristics. Understanding the key controls on fissure propagation improves the ability to predict future fissure locations. Reinstating the disbanded webcam network is crucial for improving forecast accuracy, enabling further refinement of predictive models.

Authors: Rhodes, R

• Type of award: MSc
• Level of award: Masters
• Awarding institution: University of Oxford
• Language: English
• Keywords: fire-fountains; webcam observation; fissure eruptions
• Subjects: Volcanology; Earth Science