An Early Warning System for Volcanic Eruptions

Abstract

A period of geophysical unrest started in the Svartsengi volcanic system with a swarm of earthquakes on October 25th, 2023, followed by a dike propagation event on November 10th, and six subsequent volcanic eruptions to date. The energy utility HS Orka operates a geothermal power plant approximately 1.6 km away from the closest point of the dike intrusion. The utility has been operating a downhole pressure and temperature logger in well SV-12 since 2018 to monitor how the reservoir responds to production and injection. During the event on November 10th, 2023, the logger picked up a pressure signal which had not been observed before in the history of the monitoring system. It was characterized by a rapid pressure increase, most likely due to magma movement associated with the dike propagation. This signal was again observed 35 minutes before the volcanic eruption on December 18th, which prompted the department of resource management at HS Orka to design an early warning system for volcanic eruptions. The resulting system continuously monitors the speed of measured pressure changes and sends out a warning to the Icelandic Meteorological Office (IMO) if they pass a certain threshold. The system was deployed on January 11th and sent a warning about an impending eruption to the IMO more than four hours before the eruption on January 14th. Since then, it has been able to predict the subsequent eruptions at least 25 minutes in advance. During those events, the warnings strengthened the confidence of the relevant authorities that a volcanic eruption was imminent and better enabled them to take appropriate measures to ensure public safety.