Controls on Fissure Location and Fire-fountain Dynamics: Insights from Webcam Observations of the Eruptions Between December 2023 and September 2024 from the Svartsengi Volcanic System, Iceland.

Fissure-fed eruptions are a common type of volcanic activity globally. Recent fissure-fed eruptions from the Svartsengi Volcanic System have significantly impacted Iceland’s Reykjanes Peninsula. This activity may continue intermittently for decades to centuries, so understanding the controls on the locations and propagation of these fissure-fed eruptions is vital for continued hazard assessment and risk mitigation. This study maps eruptive fissures from six eruptions between December 2023 and September 2024 using satellite and aerial imagery and quantifies fire-fountain height evolution for four eruptions using webcam footage. Fissure locations are heavily influenced by topography, including features parallel to fissure strike and features formed during previous eruptions. The maximum fire-fountain heights ranged from 56 m during the January 2024 eruption to 133 m during the August 2024 eruption. Variations in fire-fountain heights in a single eruption between different fissure segments, and through time, appear to primarily be controlled by surface vent size and dike pressurisation, both of which increase mass eruption rate and lead to higher fountains. Understanding the controls on fissure propagation highlights areas most vulnerable to future fissure opening. These insights could be used to help inform ongoing hazard assessment and risk mitigation. Digital video capture of future eruptions from multiple angles would augment monitoring and help refine further models of fire-fountain evolution.