161 Dynamics of Natural and Built Environments

Our communities, economies and infrastructure depend on interactions between the natural and built environments. Engineered systems (e.g. earthworks, structures, utilities) must be resilient to evolving natural forcings, and similarly engineered systems must also minimize negative effects on the natural environment.

Tuesday, 21 October 2025
8:00 AM - 12:00 PM
HBGCC, 214A

Grindavík and Vestmannaeyjar: Managing Emergent Volcanic Threats in Iceland

Paper number: 161-7
Program: Technical Sessions
Time: 9:40 AM – 9:55 AM

Authors

Abstract

A period of active volcanism, including episodic surface deformation, seismicity, and flowing lava, has been occurring on the Reykjanes Peninsula of Iceland from 2021 to the present. This activity has threatened the Blue Lagoon tourist center, HS Orka geothermal power plant, and the coastal town of Grindavík. Magma-driven earthquakes and deformation crescendoed on Nov. 10, 2023, causing evacuation Grindavík’s ~3800 residents (~1% of the national population). Iceland responded to this emergency with: (1) construction of large lava barriers, and (2) establishment of a government-chartered corporation, Þórkatla, that purchased >90% of the ~1100 residences in Grindavík at a cost of ~600 million US dollars (>2% of Iceland’s annual GDP).

Our group met with Icelandic officials and Grindavík residents in January 2025, and a common theme was that volcanic response in modern Iceland is shaped by events in 1973 on the island of Heimey. Thus, in July 2025, we interviewed residents of the town of Vestmannaeyjar, including some who resettled to Grindavík, and toured Heimey with the City Engineer and leader of the 1973 evacuation (5200 people=2.45% of Iceland’s population) and battle to save Vestmannaeyjar.

The 2023 evacuation of Grindavík was a shock to its residents but was logistically more straightforward than the armada and airlift to safeguard Vestmannaeyjar’s population in 1973. Damage in 1973 was due to up to 6 m of ash, collapsing some structures, and voluminous lava that flowed into town. In Grindavík, two small lava flows breached the town’s barrier (1/2024, 4/2025), with most damage caused by extension and fissuring. The 1973 Heimey eruption abated within 6 months, and undamaged structures were quickly excavated and reoccupied. The eruption was globally publicized as an epic victory in the “control of nature” and became a source of national pride and ongoing driver of local tourism.

In contrast, episodic activity continues on the Sundhnúkar crater chain that threatens Grindavík, and the town remains largely unoccupied >20 months later. Þórkatla’s buyouts stand out as the great humanitarian, political, and financial victory of Iceland’s modern eruption, but – ironically and sadly – may now be impeding the recovery and long-term viability of Grindavík. Iceland embodies “civilization at the edge of geological consent” and thus is a laboratory for paradigms of disaster response worldwide.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412918

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