Continuous lava flow threatens Grindavík barriers, Iceland

The ongoing eruption on Iceland’s Reykjanes Peninsula, starting March 16, 2024, continues to pose a threat as lava from the Sundhnúkur crater row thickens near Grindavík. Extrusion rates have remained consistent at 3 – 4 m³/s (106 – 141 ft³/s), with new data anticipated to further assess the situation.

Since its onset on March 16, 2024, the volcanic eruption on the Reykjanes Peninsula in Iceland, has consistently discharged lava. This ongoing activity has seen the lava field near Grindavík progressively thicken, particularly towards the south. The active vent, situated just east of Sundhnúkur, has been the source of the uninterrupted lava flow, which has been advancing through both open channels and a network of closed tubes, shielding the lava from atmospheric cooling.

As of the latest updates on April 15, lava extrusion rates have been measured between 3 – 4 m³/s (106 – 141 ft³/s), with further data expected to be gathered next week to provide updated insights into the volcanic activity. The development and movement of the lava have been documented by cameras positioned by the Icelandic Civil Protection, highlighting the advancing lava towards protective barriers east of the town of Grindavík.

Geophysical measurements in the region have recorded continuous ground uplift around the Svartsengi area, indicating an ongoing accumulation of magma at depth. Analytical models, supported by GNSS and InSAR data, estimate that between 7 and 8 million m³ (247 – 282 million ft³) of magma has recharged the Svartsengi reservoir since the eruption started.

Historical patterns suggest that magma might start moving towards the surface in the form of dike intrusions once the reservoir reaches a threshold of approximately 8 – 13 million m³ (282 – 459 million ft³).

The potential for significant escalations in eruptive activity remains high as long as magma continues to accumulate. New eruptive fissures could open in the areas between Stóra-Skógfells and Hagafells, or the current vent could expand if the magma flow rate suddenly increases. While less likely, additional dike intrusions could also lead to the formation of new eruptive fissures elsewhere, potentially with more extended and intense precursors.

The hazard assessment for the ongoing volcanic activity was recently revised during a scientific meeting.

The likelihood of eruptive fissures opening within certain zones (Svartsengi, Grindavík, and others) has been downgraded from considerable to low. Despite this, the risk of sudden eruptive openings remains very high within Zone 3 (Sundhnúks crater row), as assessed by experts. This reassessment follows recent geological observations and the continued inflation of the Svartsengi reservoir.

Live streams of the eruption

References:

¹ The eruption continues in Sundhnúkur crater row – IMO – April 23, 2024

Featured image credit: IMO