Reykjanes Peninsula Experiences Decline in Seismic Activity, Magma Accumulation Slows

Seismic Activity Wanes Across Reykjanes Peninsula

The Reykjanes Peninsula in Iceland is currently experiencing a notable decline in seismic activity, according to recent updates from the Icelandic Meteorological Office (IMO). This reduction in earthquake frequency and intensity is observed across the region, including areas near the evacuated town of Grindavík and the Krýsuvík volcanic system.

Specifically, only a handful of small earthquakes, mostly registering around magnitude 1, are being detected daily near Grindavík and along the Sundhnúkur crater row. Furthermore, the Krýsuvík system, which saw ground subsidence earlier this summer, has stabilized, with earthquake numbers falling sharply from approximately 250 per week to between 100 and 150. This marks the first sustained decline in several months for the Krýsuvík area.

Magma Accumulation Beneath Svartsengi Slows

In addition to reduced seismic activity, the rate of magma accumulation beneath Svartsengi is also slowing. Ground movement in the area has eased in recent weeks, with magma continuing to gather but at a reduced pace since mid-autumn. Current modeling indicates that roughly 15 million cubic meters of magma have accumulated beneath Svartsengi since the last eruption in July.

Experts from the IMO suggest that this slower inflow rate could lead to a longer interval before the next volcanic eruption. While the lower volume threshold for a new diking event was reached in early October, the upper threshold, set at 23 million cubic meters (the average amount released during the last five eruptions), is not projected to be met until early February, assuming current inflow rates persist. The volume of magma released in previous eruptions in the area has varied significantly, ranging from 12 to 31 million cubic meters.

Official Outlook and Continued Monitoring

Despite the current slowdown, an eruption on the Reykjanes Peninsula is still expected, though the timeframe has been extended due to the decreased magma inflow. The Icelandic Meteorological Office has maintained its current hazard map and risk assessment, extending its validity until November 25, 2025. However, considerable uncertainty remains regarding the precise timing of the next event.

The region has experienced a series of eruptions since December 2023, with the most recent event concluding on August 5, 2025. Authorities continue to monitor the situation closely, with updates to be issued if conditions change.