Assessing the impact of lava flows during the 2020 unrest of the Svartsengi volcanic system on the Reykjanes peninsula, Iceland

In January 2020, inflation up to 5 cm was detected in the volcanic system of Svartsengi, Reykjanes peninsula (Iceland). The inflation was probably linked to the movement of magma which was estimated to be at a depth of 3-5 km. Shortly after the detection of the inflation, the Scientific Advisory Board responsible for tackling the unrest deemed possible that the unrest could evolve into an effusive eruption. We used both the MrLavaLoba and the DOWNFLOW codes to simulate the area potentially inundated by lava flows in order to assess the hazard posed in case of an effusive eruption. The DOWNFLOW code was used to create a suite of 10,000 simulations which were used to derive maps of the lava flow hazards. These maps can be dynamically updated to account for ongoing modifications suggested by the geophysical signals of the monitoring system. The MrLavaLoba code, in turn, was tuned based on the historical lava flows in the area, so it would be ready to simulate potential lava flow fields if an eruption began. At the time of writing (April 2020), the area appears have experienced two intrusions and is currently in a waning phase. However, the lava flow modeling carried out constitutes an example of rapid response during an ongoing crisis. The post-processing of DOWNFLOW simulations can also allow for preliminary estimations of the time left before lava flow inundates given targets, providing effective support for stakeholders.