Volcano eruption at Sundhnúkur. Photo taken 10. April 2024 by Jón Bjarni Friðriksson/IMO
Increased likelihood of a new volcanic eruption
Iceland Met Office
Updated 2. May at 18:00 UTC
Land rise continues at Svartsengi. Pressure continues to build up within the magma chamber.
Lava flow from the crater, which has been decreasing in recent days, continues.
Measurements and simulations indicate that there is significant uncertainty about the future. The likelihood of a new volcanic eruption and/or an increase in the intensity of the eruption at the Sundhnúkur crater row is growing.
There is a risk that lava may breach the eastern defenses of Grindavík if the eruption's strength increases again.
The hazard assessment remains unchanged.
Land deformation continues to be measured at Svartsengi, and the rate of uplift has remained stable in recent weeks (see image below). Earlier in the week, there were indications that the rate of land rise might have slowed in the preceding days. However, measurements since then reveal that the rate has remained steady in the context of the past few weeks. Pressure continues to increase within the magma chamber, and there is a risk that the magma chamber beneath Svartsengi will feed a new volcanic eruption.
The graph shows ground movement in the vertical component at the GPS station SKSH in Svartsengi. The measurements indicate that the rate of land deformation has remained steady since the beginning of April. The blue line represents the timing of the magma intrusion, which did not culminate in an eruption, while the red lines represent diking events that resulted in an eruption. The second red line shows the onset of the ongoing volcanic eruption.
Seismic activity has increased along the Sundhnúkur crater row in recent days. These earthquakes are small, likely representing a release of stress within and around the increasingly pressurized magma chamber beneath Svartsengi.
Lava flow from the active crater is significantly lower than it was three weeks ago, and the current flow rate is measured to be relatively small. However, an eventual increase in flow rate must be considered despite the currently minimal lava flow.
The accompanying map shows changes in the thickness of the lava flow between April 15th, April 25th, and April 30th. Click the image to enlarge.
Lava from the crater has been accumulating near Grindavík's eastern defense wall in recent weeks (L12 on the image above). If the intensity of the eruption increases or new fissures open south of the current eruption site, it is expected that the lava flow will advance toward the eastern defenses of Grindavík. On Saturday, April 27th, small lava flows crossed the defenses east of Grindavík. If the power of the eruption increases again, there is a risk that such occurrences will become more frequent.
These are the most likely two scenarios regarding the continuation of activity at the Sundhnúkur crater row:
New volcanic fissures could open in the area between Stóra-Skógafell and Hagafell, and/or the current eruption site could expand due to a sudden increase in lava flow, which may be comparable to the initial phases of the last volcanic eruption in the area. This could occur with very little or no warning.
It is also possible that the flow of magma from the magma chamber beneath Svartsengi into the active vent at the Sundhnúkur crater row may increase steadily until there is equilibrium between the inflow of magma into the chamber and the outflow onto the surface.
Precursory signals of a new volcanic eruption would resemble previous events, with sudden and intense seismic activity within and around the magma chamber and land deformation in Svartsengi.
The hazard assessment by the Icelandic Meteorological Office remains unchanged and is valid until May 7th, unless the situation changes.
Follow the meteorologist's forecast for gas emissions here.
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