2023–2024 Sundhnúkur Eruptions

The 2023–2024 Sundhnúkur eruptions ( is, Eldgosin við Sundhnúksgíga 2023–2024) are an ongoing series of volcanic eruptions in the Reykjanes Peninsula, near the town of Grindavík, Iceland. , there have been six eruptions between December 2023 and August 2024, following an intense series of earthquakes. Although localised, the seismic and volcanic activity have caused significant disruption across the western part of the peninsula, especially for the town of Grindavík.

The eruptions were preceded by an intense earthquake swarm in the Eldvörp–Svartsengi volcanic system that began on 24 October 2023, caused by a magmatic intrusion underneath the area. The frequency and intensity of the earthquakes dramatically increased on 10 November 2023, with around 20,000 tremors recorded by that time, the largest of which exceeded magnitude 5.3. An evacuation was ordered in Grindavík, and large-scale subsidence in and around the town caused significant damage.

The first eruption started on the evening of 18 December 2023, at the Sundhnúksgígar crater row north of Grindavík, with lava spewing and spreading laterally from both sides of the fissures, which were about long. The eruption was preceded by land uplift in the Svartsengi area, which deflated upon eruption, indicating magma accumulated in a storage area under Svartsengi feeding this and all subsequent eruptions at Sundhnúksgígar. The eruption was described as the largest in the Reykjanes Peninsula since the beginning of eruptive activity in 2021. The duration of the eruption, however, was relatively short, with the intensity of the eruption subsiding early on 19 December, and the eruption ended on 21 December.

On 14 January 2024, a second fissure erupted north of Grindavík. A few hours later, a smaller fissure opened less than from the town inside the protection barriers, with its lava reaching and burning down three residential houses. Just before the second eruption, one individual was reported missing, and presumed to have fallen into a crevice formed from the seismic activity and died.

A third eruption began on 8 February 2024 in the same area as the December eruption, with a fissure about long effusively erupting lava on top of earlier flows. The lava flowed over a road and caused significant damage to utility infrastructure.

A fourth eruption commenced on 16 March 2024, originating from a fissure approximately in length. The eruption concluded on 9 May after persisting for 54 days, making it the longest of the five eruptions documented in this eruptive series to date. A magma intrusion had previously occurred on 2 March but did not breach the surface, potentially delaying the onset of the fourth eruption.

The fifth eruption began on 29 May and finished on 22 June. It lasted for 24 days, and the volume and area of its lava flows were the largest of the five eruptions to date.

On 22 August, the sixth eruption in the ongoing series began after a strong earthquake sequence, the largest of which had a magnitude of 4.1. The eruption quickly expanded, forming fissures up to long at its peak and producing rapid lava flows. It concluded on 6 September, around 14 days later.

Etymology

The name " Sundhnúkur" literally translates to "passage peak". It is the highest point in the old crater row in the area, standing at . Historically, the name reflects the navigational challenges faced by sailors due to numerous rocks and skerries near the shore. Sundhnúkur served as a crucial visual marker for sailors navigating to the town of Grindavík, as its peak was visible from beyond the shore. The actual passage through the rocks has a different name, underscoring that Sundhnúkur refers specifically to the peak as a landmark rather than the passage itself. Sailors of the time also needed to be knowledgeable about various leading marks to safely reach the harbor. The term " Sundhnúksgígar", meaning "passage peak craters", was coined by geologist Jón Jónsson in 1974, highlighting the series of craters associated with this notable landmark.

Background

The Sundhnúksgígar crater row was formed approximately 2420 ± 100 radiocarbon years before present (BP), as determined by carbon-14 (¹⁴C) dating conducted by Uppsala University, using 1950 as the baseline. This ancient lava flow was measured to cover an area of and has an estimated volume of at least . It originated from a crater row extending nearly in length. The crater row includes two named craters: Sundhnúkur and Melhóll , with the latter situated nearly to the south-west of Sundhnúkur. The lava from this period was a mixture of pāhoehoe and ʻaʻā lava, indicative of varying eruption dynamics. Additionally, there are likely traces of an even older lava field beneath the circa 2400-year-old lava, though much of it has been obscured by the more recent eruption.

The Reykjanes Peninsula, located in south-western Iceland, has entered a new volcanic cycle after a period of approximately 800 years of relative inactivity. The most recent phase of this activity, known as the Reykjanes Fires, occurred between 1210 and 1240 AD, primarily in the Eldvörp region west of Svartsengi and the hyaloclastite mountain Þorbjörn , with volcanic activity extending both north-east and south-west from that area. This resumption of activity was signaled by increased seismic and volcanic activity near Þorbjörn beginning in late 2019. Volcanic cycles on the peninsula typically last 300 to 400 years, with eruptions occurring at six to seven separate locations, including areas near the Capital Region. Individual eruptions within a cycle can persist for 10 to 20 years, with activity shifting to other sites every 30 to 50 years. Based on historical patterns, the current cycle is expected to continue until approximately 2300–2400 CE.

The Eldvörp–Svartsengi volcanic system has experienced eleven magmatic intrusions since January 2020, eight of them since November 2023. Six of these intrusions have resulted in volcanic eruptions, whereas the others did not reach the surface. Previous volcanic unrest during this period had been predominantly associated with the Fagradalsfjall system, where three out of four magmatic intrusions led to eruptions. Since 2021, there have been a total of nine identified volcanic eruptions on the Reykjanes Peninsula.

Iceland frequently experiences earthquakes due to its position on the Mid-Atlantic Ridge, where the Eurasian and North American tectonic plates meet. However, the 2023 swarm was unusually extensive and is linked to a magmatic intrusion approximately long, extending south-west from Kálffellsheiði and aligning with the Sundhnúksgígar crater chain at a depth of roughly . The largest earthquakes originated beneath the Sundhnúksgígar craters, then spread south-westward beneath the town of Grindavík and offshore. Grindavík lies on lava flows from the Sundhnúksgígar crater chain's last eruption approximately 2,400 years ago and is one of six Reykjanes Peninsula communities located on or near eruptive fissures.

Earthquakes

October 2023 earthquakes

From 24 October to 31 October, the Reykjanes Peninsula was engulfed in a significant seismic episode, beginning with an intense earthquake swarm on the evening of 24 October around the Þorbjörn and Svartsengi areas, attributed to magmatic intrusion. This onset featured over 1,000 earthquakes, intensifying the seismic unrest that had seen the peninsula experiencing over 700 quakes earlier in the month, the strongest of which was magnitude 3.3. By 28 October, the situation escalated dramatically, with the IMO reporting a total of over 7,000 earthquakes. This count increased with an additional detection of around 1,300 earthquakes on 30 October alone, pushing the cumulative tally even higher. The earthquakes, primarily at depths between , focused their intensity around the Eldvörp–Svartsengi region, north of Grindavík. Throughout this tumultuous period, the IMO, alongside Civil Defence and local stakeholders, maintained close surveillance of the seismic activity.

The first signs of a magma intrusion near the Svartsengi area, located north-west of Þorbjörn on the Reykjanes Peninsula, were detected in October. This phenomenon, identified through the latest GPS data and InSAR images derived from satellite data, indicated an accelerated rate of land rise, centred near the Blue Lagoon, approximately north-west of Þorbjörn. It was the fifth occurrence of such land uplift in the area since 2020, suggesting increased pressure likely due to magma intrusion. The rapid uplift raised the likelihood of more frequent seismic activity in the area that could potentially allow magma to move closer to the Earth's surface. Experts conducted models to estimate the depth and size of the intrusion, amid expectations of a potential volcanic eruption within the next year.

November 2023 earthquakes

The largest of the earthquakes to date reached magnitude 5.3 on 10 November. By this time, over 22,000 earthquakes had been recorded since the beginning of the swarm in October. The IMO predicted that an eruption was likely, stating that "it will take several days (rather than hours) for magma to reach the surface". The greatest extent of the magma intrusion was inferred to be around the Sundhnúksgígar crater chain, approximately north of Grindavík. Instruments detected the presence of sulfur dioxide (SO₂) in the atmosphere on 14 November, indicating that magma was only a few hundred metres (a couple of thousand feet) under the surface. Although the number of earthquakes decreased somewhat since 10 November, the IMO was still recording between 700 and 1,000 earthquakes daily by 14 November.

Ground deformation sensors at Festarfjall and Svartsengi recorded that the ground had moved apart by . Satellite measurements recorded the subsidence depth by about of a swathe of land measuring approximately 5 km long and 2 km wide (), running from the Sundhnúksgígar craters to the western side of Grindavík. The creation of this graben-like formation on 10 November has enabled scientists to estimate the volume of the magmatic intrusion, which formed in a remarkably short period of 6 hours, as approximately . Further analysis revealed that about flowed into this magma intrusion, providing valuable insights into the dynamics of volcanic processes and the scale of subsurface magma movement. It was estimated that the subsidence continued at a daily rate of about in the week following the disaster. A large crack opened up through the town, which old maps indicate is a reactivation of an existing fault. Scientists at the University of Iceland believe that the fault was created by the last Sundhnúkur eruption over 2,000 years ago.

Sensors emplaced in a borehole in Svartsengi detected the presence of sulfur dioxide on 16 November, a classic signature of magma close to the surface. This led the IMO to conclude that the area around the volcanic edifice of Hagafell , approximately north of Grindavík, is at the highest level of risk. A rapid uplift of the ground in the Svartsengi area was recorded from 18 to 21 November, likely indicating an upwelling of magma from a source below the ground. An eruption was still regarded as likely on 21 November, but as seismic activity declined from 24 November, that likelihood also began to decline.In November 2023, Benedikt Ófeigsson, a geophysicist at the IMO, posited that Fagradalsfjall, rather than Svartsengi, might be the source of volcanic activity near Grindavík, noting the difficulty in assessing the activity's depth, location, and magma volume amidst seismic disturbances. He anticipated that InSAR satellite imagery would clarify these uncertainties. Supporting Benedikt's hypothesis, Freysteinn Sigmundsson from the University of Iceland, in February 2024, observed that minor seismic activity near Fagradalsfjall indicated potential magma movement, hinting at a possible eruption. He highlighted the magma's potential new pathways, particularly its shift towards the Svartsengi system and the persistent pressure in Fagradalsfjall post-eruption. Additional evidence bolstering the theory comes from the pattern of land uplift in these systems. In Fagradalsfjall, an uplift began following the end of volcanic activity in early August 2023 and persisted until the end of October 2023. Notably, as this intrusion concluded in Fagradalsfjall, a fresh phase of land uplift initiated in Svartsengi around the same time. Scientists from Uppsala University appear to have confirmed the theory proposed by their counterparts at the University of Iceland.

According to Professor Magnús Tumi Guðmundsson, a geophysicist at the University of Iceland, the magma channel, approximately wide, had undergone rapid solidification. Approximately 90% of the magma solidified within 10 to 15 days following the subsidence in November 2023, due to the cold nature of the Earth's crust. However, some magma near Sundhnúksgígar remained, posing potential risks for further activity due to the possibility of increased underground pressure. Magnús noted that while magma generally cools quickly, the surrounding rock stays hot and weak, maintaining a state of geological vulnerability in the area for several months, necessitating ongoing caution and monitoring. If an eruption were to occur, it was most likely to take place in the area between Sýlingarfell and Hagafell mountains. Over the span of several weeks, the possibility of an eruption in Eldvörp, north-east of Grindavík, was also being monitored.

Significant land movements were recorded around the Svartsengi area during the subsidence, with a displacement of about to the west and to the north. During the evacuation of Grindavík on 10 November, the ground near Svartsengi initially descended by and subsequently rose by . A GPS station at Festarfjall, situated east of Grindavík, underwent a shift of eastward and south-ward, along with an upward movement of . Moreover, the GPS station in Grindavík, directly above the magma conduit, moved eastward. On 10 November, at the aforementioned location, there was also a dramatic drop of , followed by an additional sinking of .

December 2023 earthquakes

On 1 December the Reykjanes Peninsula, near Svartsengi in Iceland, experienced a notable decrease in seismic activity, primarily recording micro-earthquakes below magnitude 1, mainly concentrated between Sýlingarfell and Hagafell. Despite this decline, continuous deformation observed at nearby continuous GPS stations suggested ongoing adjustments due to inflation within the Svartsengi area. By 6 December, geodetic modeling results indicated that the magma inflow to the dike formed on 10 November 2023 had likely ceased, significantly lowering the risk of an eruption along this dike. However, the continued accumulation of magma beneath Svartsengi indicated that the volcanic unrest was not concluded, with a potential for new magma propagation events and an increased eruption risk. Through mid-December, sustained, albeit generally weak, seismic activity around the area, including over 460 earthquakes with a notable magnitude 2.8 tremor near Hagafell, underscored the ongoing geological unrest. Despite a slowdown in deformation rates observed by 16 December, the situation remained dynamic, with the potential for further volcanic activity under close scrutiny by scientists.

It is most likely that the magma accumulating under Svartsengi is feeding the Sundhnúksgígar crater chain, where the magma intrusion occurred. Deformations are still being measured at stations near the conduit, but it is believed that this is due to the land uplift occurring at Svartsengi. At the beginning of December, recent GPS data from the IMO showed that the land had risen above its level prior to the start of the earthquake series in end of October 2023. Professor Þorvaldur Þórðarson, a volcanology expert from the University of Iceland, theorized that this elevation could be attributed to a combination of tectonic movements and magma build-up. Notably, the pronounced terrestrial shifts on 10 November may have facilitated the migration of magma from deeper reservoirs to more superficial ones.

In the weeks following the subsidence, the volcanic activity at Svartsengi entered a new phase with increased chances of magma propagation and potential eruptions. The observed pattern suggested a possible repetition of events, where magma accumulating beneath Svartsengi feeds a dike beneath Grindavík and north-east towards Sundhnúksgígar, similar to the one formed on 10 November. In the beginning of December, the magma flow was accumulating under Svartsengi at a rate comparable to the discharge of the Elliðaár rivers in Reykjavík, or several cubic m/s (a few hundred cu ft/s). The magma was believed to be located at a depth of about .

The recent seismic trends at Svartsengi, characterized by varying intensities and a concentration of activity along a dike, closely resembled the seismic and volcanic patterns experienced during the Krafla Fires, which began in 1975. In these old eruptive series, the region witnessed over a period of ten years 20 distinct magma propagations, nine of which culminated in eruptions. These events were marked by varying magma volumes feeding the same dike, leading to different eruption scales. In Svartsengi, geodetic data showed a similar pattern of reduced magma volumes compared to levels observed before the 10 November dike intrusion, parallelling the smaller magma accumulations at Krafla that were sufficient to trigger new propagations and subsequent eruptions.

From the beginning of the earthquakes until 10 November, the land at Svartsengi elevated by more than within a span of 16 days. Following a substantial subsidence of , a new phase of activity led to a land rise of over an equivalent 16-day period. This same phase then peaked at about before the first eruption on 18 December later that year, thereby reaching the same height as prior to the subsidence. Typically, the land undergoes a sharp descent before each intrusion and eruption, followed by a gradual ascent thereafter. The previously mentioned subsidence was caused by the movement of magma from Svartsengi, passing beneath Grindavík, and extending towards Sundhnúksgígar to the north-east.

March 2024 earthquakes

An earthquake swarm on 2 March 2024 was interpreted as a magma intrusion that did not reach the surface. Modeling calculations indicated that the magma intrusion was approximately long, extending from Stóra-Skógfell to Hagafell. The magma within this intrusion lied at a depth of at its shallowest point, reaching down to about . The calculations estimated that approximately of magma flowed into Sundhnúksgígar during the magma transfer, significantly less than previous events where it was estimated that around had flowed from Svartsengi into the craters. Before the intrusion, about had accumulated in the chamber under Svartsengi. Magma typically seeks the path of least resistance to the surface, and it is challenging to ascertain what prevented this during the event. Potential obstacles in the magma's path, insufficient volume, or pressure to open a vent, or a combination of these factors could have played a role. The magma intrusion behaved differently from previous transfers, warranting further investigation to enhance understanding of the nature of such events in the area and to anticipate future developments.

Eruptions

December 2023 eruption

On 18 December 2023, an eruption occurred at approximately 22:17 UTC, following a series of small earthquakes that started about 77 minutes earlier. The IMO pinpointed the origin of the eruption near Hagafell, about north-east of Grindavík, and noted that the eruption stemmed from a fissure with a length of about , with lava flowing at a rate of around adding that seismic activity appeared to be moving towards the direction of Grindavík. The eruptive fissure followed approximately the line of the Sundhnúksgígar crater row formed from previous eruptions more than 2,000 years ago. An Icelandic Civil Defence official informed the nation's public broadcaster, RÚV, that the eruption occurred rapidly and appeared to be "quite a large event". The eruption was described as the largest in the Reykjanes Peninsula since the beginning of eruptive activity in 2021, with lava fountains, up to high, and was visible as far away as the capital Reykjavík, away.

Scientists estimated through model calculations that nearly of magma accumulated in the chamber, located several km (several mi) deep, before the December eruption. Of this, approximately ascended to the intrusion, initiating the eruption. The lava field covered a total area of approximately . On a single day during the eruption, the release of sulfur dioxide was approximately . This sulfur dioxide subsequently reacted with water vapour in the atmosphere to form even more toxic sulfuric acid (H₂SO₄). The emission was proportionally about ten times greater than the gas output observed in previous eruptions at Fagradalsfjall.

Following the eruption, the Icelandic Coast Guard deployed a helicopter to the area to monitor activity. Numerous delays were reported at Keflavík International Airport, which remained open. The Blue Lagoon spa, which had reopened the day before, did not take bookings on the night of the eruption. Police raised the risk level while the Civil Defence authorities warned the public not to approach the area while emergency personnel assessed the situation. By 19 December, the scent of smoke and ash was detected as far as from the eruption site, raising fears that volcanic gases could reach Reykjavík by the next day. However, the gas would never extend to dangerous levels there; it could only cause mild discomfort at most. On the same day, the Icelandic Coast Guard rescued a man who had gotten lost near the eruption site using a helicopter. Authorities advised citizens who were in the town during the eruption to evacuate via Route 427 (Suðurstrandarvegur), as the eruption was most likely to threaten Route 43 (Grindavíkurvegur). Officials said residents of Grindavík would be allowed back into the town. This eruption, along with the August–September eruption, remains the only one in the series that caused no damage to infrastructure. On 21 December, the IMO officially declared the eruption concluded after a significant decrease in activity.

January 2024 eruption

On January 14, 2024, at approximately 7:57 UTC, a second volcanic eruption began about north of Grindavík, following seismic activity originating from the Sundhnúksgígar crater. Although described as "not very big", fissures appeared on both sides of the anti-lava defences, and it was estimated that lava could reach the town within 24 hours. A successful mission was launched to save several pieces of heavy machinery worth about ISK 800 million (), which were used to construct the barriers. The lava flow cut off one of the main roads leading into Grindavík, and the initial fissure extended up to . Prior to the eruption, more than of magma had accumulated beneath the Svartsengi area, with only a small portion of that having been emitted above ground.

Before the eruption began, scientists observed that magma intrusion seemed to have reached beneath the town of Grindavík. Just a few hours later, around noon, another fissure measuring about opened only several tens of metres (a few hundred feet) from the outermost houses of the town, subsequently setting three houses on fire before ceasing after a few hours. Evacuation orders were reissued in Grindavík, and the Icelandic Coast Guard deployed a helicopter to monitor the situation. Dr. Evgenia Ilyinskaya, a volcanologist from the University of Leeds, suggested that this eruption indicated the Reykjanes Peninsula might be entering a long-term period of frequent eruptions, potentially lasting for centuries. She referred to this period as the New Reykjanes Fires, drawing a parallel to a similar event in the 13th century, which marked the previous active volcanic period on the Reykjanes Peninsula.

By January 15, volcanic activity had "decreased considerably", and the eruption was declared over on January 16, just after midnight. In the aftermath of the eruption, scientists discovered a new graben valley, located further east than the one formed during the November intrusion. The new valley measured up to wide and deep, in contrast to the older valley, which reached up to in width and in depth. This eruption was the smallest in the current series, affecting only about and producing of lava. The maximum lava discharge was . It remains the only eruption that actually reached the town's borders.

February 2024 eruption

On 8 February at 6:03 UTC, the third eruption started north of Sýlingarfell following intensive seismic activity that began 30–40 minutes prior. The eruption produced lava fountains measuring between in height and a volcanic plume up to high. A long fissure opened in the same area as the December eruption, between the Sundhnúksgígar craters and the hill of Stóra-Skógfell, about north-east of Grindavík. Although about of magma had gathered below Svartsengi just before the event, the IMO estimated that of lava erupted on 8 February alone, representing a flow of about for the first seven hours.

Less than three hours after the eruption began, infrastructure was said to be "in no danger at the moment". However, an hour later, it was estimated that there was a risk of the lava front flowing over the main hot water delivery pipeline running from the Svartsengi power station. Five hours after the eruption commenced, authorities declared the situation "very serious", and by the sixth hour, the lava had already flowed over the pipeline, causing serious damage to infrastructure near the Svartsengi power station, although Grindavík remained at a safe distance. All premises of the Blue Lagoon area were evacuated the night before the eruption, with earthquakes as indicators. Unlike previous eruptions on the peninsula, the 8 February eruption produced quantities of black ash mixed with steam, theorized to result from groundwater boiling and mixing with magma to create ash.

Volcanic activity subsided later on eruption day and came to a complete stop in the afternoon of 9 February. On 10 February, the IMO formally declared the eruption over. This eruption has so far caused the most damage to infrastructure, yet it is the shortest so far, lasting only about one and a half days. The rapid and insidious lava flow caught response teams in the area off guard, as a series of unfortunate events allowed the molten rock to overrun the infrastructures unrestrained. About two-thirds of the lava flowed west into the Svartsengi area, extending up to from the eruption centre. The lava covered about after the conclusion of the eruption.

March–May 2024 eruption

On 16 March at 20:23 UTC, the fourth eruption started between Hagafell and Stóra-Skógfell, with impressive lava fountains that were several dozen metres (a few hundred feet) in height. Both the Blue Lagoon and Grindavík were evacuated. A fissure opened up, producing two lava flows going in different directions. The first was seen to be moving in a westward direction towards the Blue Lagoon and the Svartsengi power plant and reached Route 43 (Grindavíkurvegur) leading into Grindavík, raising concerns that it could damage fiber optic cables laid on the road and cause internet and telecommunications disruptions. The second lava flow was seen to be moving south, reaching the eastern protective walls of Grindavík at a speed of . The IMO said the eruption was "significantly wider" than the eruption of the previous month, while a geophysicist who observed the eruption during a helicopter flight described the eruption as the "most powerful" so far of the current eruption sequence. A state of emergency was declared again over the region on the day of the eruption, but it was downgraded to Alert Phase on 3 April. Volcanic activity significantly diminished in the days and weeks following the onset of the eruption but continued nonetheless.

During the initial phase of the eruption, the lava flow rate surged to between within the first hour. However, this intensity rapidly waned, with the ejection rate diminishing to approximately within six to eight hours of onset. By 17 March, one day after the eruption began, the newly formed lava field covered nearly . By 20 March, the average lava output had decreased to around . Between 20 and 27 March, the average lava flow rate reduced to approximately . From 27 March to 3 April, the average flow rate was estimated at , further decreasing to between 3 and 8 April. The lava bed had expanded to cover an area of by 9 April, with a volume of , and only one active crater remained. Throughout this period, there was a consistent upward movement of land due to magma flow. By the first half of April, the average ejection rate further decreased to approximately . In the final two weeks leading up to the conclusion of the eruption, the lava ejection rate had diminished to .

There was an indication that magma was primarily emerging from a deeper chamber and bypassing the intermediate storage at beneath Svartsengi, previously the exclusive reservoir for the last three eruptions. Such direct access from the deeper source, located at depth, may have explained the prolonged activity of the eruption. In early April, Professor Þorvaldur Þórðarson, observing the decline in thermal imaging signals and magma output, suggested the eruption was weakening. The darkening of gases and the halt in land uplift underscored a shift in the magma dynamics, now dominated by the deeper magma source. This pattern echoed the initial stages of the 2021 Fagradalsfjall eruption, marked by low magma activity. He also posited that a reduction in magma flow to below would have heralded the cessation of the eruption in the foreseeable future. Land uplift had halted when the March–May eruption began but resumed at the beginning of April at a slower pace than after the previous three eruptions. As a result, approximately half of the magma flow was diverted to the shallower magma chamber, while the other half continued to the surface.

The eruption began with the shortest notice so far, marked by the fewest precursor earthquakes and the shortest time from these initial signs to the onset of the eruption. Moreover, it was initially noted to be more intense than its predecessors in the series, establishing it as the most energetic volcanic activity observed since the 2014–2015 Bárðarbunga eruption, until it was later surpassed by the May–June eruption. It has been the longest of the five eruptions that have occurred since the first one in December 2023. Access to the eruption area has been prohibited, as it was with previous eruptions. However, some tourists have still been caught and turned back, though this has not been a significant issue.

After almost 24 hours without any lava activity from the crater, the eruption was officially declared over on 9 May. By the time it ceased, the lava field had expanded slightly to approximately , up from its initial coverage of just under after the first day of the eruption. The total volume of lava produced is estimated at around . According to the Institute of Earth Sciences at the University of Iceland, although this eruption was significantly smaller than the 2021 event, its volume was three times greater than that of the December 2023 and February 2024 eruptions.

May–June 2024 eruption

On 29 May at 12:45 UTC, a fifth eruption commenced following the opening of a fissure near Sundhnúksgígar, initially estimated to be over in length. This eruption produced lava fountains reaching heights of and plumes ascending to an altitude of . Volcanic smog, consisting of sulfate ions, was also detected far from Iceland with satellite imagery. Approximately an hour and a half later, the fissure had expanded to a width of , consistent with the pattern observed in previous eruptions. Evacuations were again ordered in Grindavík and at the Blue Lagoon. This eruption followed a week with around 400 recorded earthquakes in the area while about of magma had accumulated underground. The lava flow in the first four hours of the eruption was estimated to average around , surpassing the previous record holder of the series, the March–May eruption.

A team from the Icelandic Institute of Natural History and the National Land Survey of Iceland analyzed data collected by experts from Verkís, Efla, and Svarmi during a drone flight over the eruption sites on 3 June. The data revealed that the lava field covered an area of and has a volume of approximately , indicating an average flow rate during that period of close to . By 10 June, the lava field had expanded to around with a total volume of , and the average flow rate had decreased to approximately . Lava lakes formed as a result of lava pooling with little or no flow velocity, particularly against Sýlingarfell. In the initial days following the start of the eruption, the number of active craters reduced to three, and about a week later, only one crater remained active until the eruption concluded.

Initial geochemical data indicates that new and altered magma had accumulated beneath Svartsengi since early April when the land uplift began, leading up to the May–June eruption. The magma, distinct from the one feeding the March–May eruption, likely gathered in a separate chamber within the middle crust and exhibited a low K₂O/ TiO₂ ratio during the May–June eruption, a first since the 2021 Fagradalsfjall eruption. Scientists believe the two magma systems under Svartsengi are interconnected deep within the Earth's crust. Two days after the May–June eruption began, sulfur dioxide levels in Edinburgh, Scotland spiked to 2,322 times higher than usual, the highest in about 50 years, due to strong North Atlantic winds. Despite the elevated gas levels, local authorities confirmed that there was no threat to the inhabitants of Edinburgh, situated approximately from the volcano. Such phenomena were observed during significant fissure eruptions in Iceland, like the 2014–2015 Bárðarbunga eruption in Holuhraun, which released nearly of sulfur dioxide over its six months of activity, surpassing Europe's total annual SO₂ emissions and affecting multiple countries across the continent.

At its most intense, the eruption released a large amount of ash at the southern end of the fissure due to contact with accumulated groundwater from recent rain, resulting in numerous explosions and even more violent interactions than in the February eruption. Lava flowing towards Grindavik was deflected by protective barriers, but two of the three main roads leading to the town were cut off. Volcanic activity decreased on 30 May and stopped on 22 June. Lasting for 24 days, the eruption produced a volume of about and covered an area of , making it the largest eruption in this series in all aspects.

August–September 2024 eruption

On 22 August 2024, the sixth eruption in the ongoing volcanic series commenced at approximately 21:25 UTC, following a significant sequence of earthquakes that began roughly 37 minutes earlier. The most substantial tremor in this series registered a magnitude of 4.1, the biggest in the area since December 2023. About 30 minutes after the eruption began, the newly formed fissure was estimated to be around in length. The fissure rapidly extended, reaching nearly within another 40 minutes. Lava flows from the fissure advanced approximately every 10 minutes within the first half an hour, with the average lava flow rate during the initial hours of the eruption estimated up to , marking the highest rate recorded in the series thus far. Approximately five hours after the eruption began, a new fissure opened north of the already active fissure line. At its peak, scientists estimate that the total extent of the eruptive fissures reached about , although not all sections were active simultaneously.

The Blue Lagoon was safely evacuated, with approximately 1,300 guests and staff relocated without incident. The nearby town of Grindavík remained largely unaffected, though residents of over 20 homes were also evacuated as a precaution. Keflavík Airport continued normal operations, but Route 41 (Reykjanesbraut) was temporarily closed to allow emergency response teams better access. The road was later reopened, but with a temporary speed limit of between Route 43 (Grindavíkurvegur) and Route 421 (Vogavegur) due to drivers stopping on the wayside of the highway to view the eruption, creating a danger. Authorities were stationed near the eruption site to restrict access, as the area is considered a hazard zone.

The Icelandic Coast Guard flew its helicopter to visualize the eruption, along with scientists. Favorable wind conditions during the initial days of the eruption directed volcanic gases southward, toward the ocean. As a result, gases from the volcano were carried with winds to countries like Scotland and Spain. The eruption remained visible from the Capital Region for several days and was even observable from more distant towns. A few days after the eruption began, the lava started to approach an old bomb practice area in Vogaheiði �vɔːɣaˈheiːðɪ This area was used by the United States Army between 1952 and 1960 for practicing with explosives, including mortar bombs, cannonballs, and small rockets. Concerns arose because the area is highly polluted, and many unignited explosives remain scattered over an extremely large site. The lava from the eruption was monitored closely to mitigate any potential risks related to these explosives. The eruption caused no damage to infrastructure.

The lava initially flowed mostly to the south and west but, in its last days, flowed almost exclusively to the north toward Route 41 (Reykjanesbraut), with only about left and even less distance remaining to the Suðurnesjalína power line, which connects the towns on the Reykjanes Peninsula to the Capital Region. The eruption was the first in the series to cross into a new municipality, reaching Vogar �vɔːɣar̥in the north. The eruption also caused up to of subsidence due to of magma flowing from the reservoir under Svartsengi to the Sundhnúksgígar crater chain. A few days after the eruption began, the lava flow rate had dropped below , and the affected area had already reached . By 3 September, only two erupting craters remained active. On 6 September, the Icelandic Meteorological Office officially declared the eruption over. Lasting approximately 14 days, it was the third longest in the recent series of volcanic events.

Wildfires

During the first weeks following the start of the March–May eruption in 2024, wildfires broke out on the Svartsengi area. The fires, unlike the extensive wildfires during the Fagradalsfjall eruption in 2023, which spread across vast distances, are presently contained within a localized region. However, very dry soil and gentle breezes raised the risk of the fires' spread, especially with lava temperatures soaring between . Firefighting efforts, characterized by manual labour and the strategic use of tanker trucks—including a notably powerful truck from the Rescue Team in Vík í Mýrdal—were undertaken between firefighters in Grindavík and the Fire Protection Services of Árnessýsla and Suðurnes, as well as the Þorbjörn Rescue Team. Emergency crews successfully gained control over the wildfires in beginning of April, with most of the flames having been extinguished.

Minor wildfires broke out in the Svartsengi area again at the beginning of June 2024, shortly after the May–June eruption had commenced. Firefighters reported that while extinguishing the fires was manageable, they had to remain vigilant to prevent the fires from getting out of control. The fires were anticipated due to the dry period in the area following the onset of summer. A few days later, additional fires began in the area, similar to those previously extinguished. The firefighting efforts were well-supported by a strong labor force from Grindavík and additional teams from the Capital Region.

In late August, wildfires broke out in several areas on the Reykjanes Peninsula due to the lava flow from the August–September eruption. The fire chief in Grindavík stated that the dry terrain and strong winds made it easier for the fires to spread. The area was used as a military training ground by the United States Army in the post-war period, making it inaccessible to fire trucks. The fires were initially too close to the lava field for emergency responders to intervene safely, but as they moved farther from the eruption site, more time became available to prepare for extinguishing them.

Impact

Grindavík

Grindavík is currently mostly abandoned due to the volcanic activity and its inhabitants have been evacuated, although they have been permitted to return for short visits to remove personal effects and goods from their homes and businesses. Additionally, homeowners are permitted to reside in their properties. This represents the first time that an entire community has been evacuated in Iceland since the eruption of Heimaey's Eldfell in 1973. Presently, it is difficult to predict when Grindavík will become habitable again; however, scientists anticipate that the current conditions could persist for months or even years. The current civil protection phase in the area is classified as "Alert Phase".

At 23:20 UTC on 10 November, the Department of Civil Protection and Emergency Management held an emergency briefing to announce a mandatory evacuation in Grindavík. Prior to this, reports indicated that residents had already relocated due to persistent tremors that disrupted sleep and raised concerns about potential consequences. During the evacuation, the Icelandic Red Cross accommodated approximately 1,700 displaced residents at three emergency centers located in Keflavík, Kópavogur, and Selfoss. Of these, about 140 individuals spent the night in these centers, while the majority found alternative accommodations independently. All residents in the Grindavík area received an SMS message from 112, Iceland's emergency service, with the headline "EVACUATION". Notably, two individuals in the town inadvertently slept through the evacuation and were discovered by police the following morning. Evacuated residents from Grindavík have relocated to 24 different municipalities across Iceland, with most now residing in the neighboring town of Reykjanesbær.

Following the 5.2 tremor on 10 November, a state of emergency was declared, and evacuation plans were put into effect for Grindavík. This culminated in the relocation of nearly 4,000 residents, almost 1 percent of Iceland's entire population. The Department of Civil Protection and Emergency Management deployed the Icelandic Coast Guard Vessel ''Þór'' to the area "for safety purposes". It also closed all roads to Grindavík except for emergency and evacuation purposes. On 13 November, authorities allowed residents to return briefly to the town to retrieve their belongings. Boat owners were also allowed to remove their vessels from the harbour. The Icelandic government sought to accommodate displaced residents in holiday homes and little-used properties during the emergency in November and December. The subsidence, faulting and earthquakes have caused widespread damage to properties and infrastructure in the town. Since the November disaster, subsidence, earthquakes, and lava flow have led to multiple disruptions in the town's electricity and hot water services. The seismic activity has received significant coverage by the international media.

The Icelandic government had plans to assist around 700 residents, who are part of about 200 families, from the original 3,700 population of Grindavík. The project included purchasing up to 210 new apartments through two non-profit housing associations, primarily in the Reykjanes area and the Capital Region. This was to be supplemented by temporary financial support for increased housing costs, with the entire support system estimated to cost about ISK 220–240 million (at least ) per month, subject to a three-month reassessment with extensions. This initiative represented a comprehensive effort to provide both immediate and sustainable housing solutions for Grindavík's displaced residents. On 1 December, the government, in partnership with the Government Property Agency, began seeking additional temporary rental properties from private and corporate owners to assist displaced Grindavík residents as part of a larger pre-established housing support program that includes wage and rental subsidies. A week later, a platform for Grindavík residents was launched online, targeting temporary housing in the Reykjanes Peninsula, the Capital Region, and neighbouring municipalities. It enabled direct leasing between residents and property owners, supported by government rental subsidies.

In a collaborative response to the disaster and ongoing uncertainty in Grindavík, Iceland's major banks—Arion Banki, Íslandsbanki, and Landsbankinn, in partnership with Finance Iceland—agreed to waive interest and indexation on housing loans for Grindavík residents for three months. This relief applied to loans up to ISK 50 million (). The measure aimed to provide equitable support, including options like deferred loan repayments. Each bank further outlined the specifics of these relief measures, ensuring they are tailored to the evolving needs of their customers in Grindavík.

On 23 February, the Icelandic government enacted a law to acquire all residential real estate in Grindavík, initially estimating the cost at ISK 61 billion (). However, the current projection indicates the total expenditure will be ISK 75 billion (), including the assumption of all unpaid mortgages. The operation, under the supervision of the newly established real estate company Þórkatla, aims to relieve the residents' distress and uncertainty following seismic activities since the previous November. The law also granted Grindavík residents until the end of 2024 to decide if they wish to sell their property to the state. Homeowners then have a right of first refusal to repurchase their properties within three years after the law's enactment. As of 27 June 2024, Þórkatla, under the government's supervision, had received nearly 900 submissions from Grindavík residents, with 740 of them completed. A total of approximately 930 properties are part of the project, with around 50% of them submitted in the latter half of March, just weeks after the application process opened. Þórkatla will rent these properties at 25% of Suðurnes's market rate to provide temporary housing for residents who might want to live there. While industrial properties and businesses within the town will not be subject to acquisition, the Icelandic government will continue to offer various forms of aid, including support loans and wage assistance, consistently providing additional benefits to both the town's businesses and the evacuated citizens.As part of the government's comprehensive plan, which includes efforts by the Department of Civil Protection and Emergency Management to prevent freezing damages in houses and ensure that Grindavík remains functional and safe for future habitation, up to 100 electricians and plumbers were mobilized to conduct critical repairs and upgrades, mostly from November 2023 to February 2024. This initiative also involved essential infrastructure work to secure and maintain the electrical and plumbing connections between the town and the power station, especially in January, when Grindavík's water main was engulfed by lava from the eruption. Specialized teams were also deployed to fill in cracks and faults resulting from seismic activity.

The State Commissioner of Police, in consultation with the Police Commissioner in the Reykjanes Peninsula, downgraded the risk level in Grindavík from Emergency Phase to Alert Phase, which was effective from 23 November 2023 until the December eruption. This decision, based on a new assessment by the Icelandic Meteorological Office (IMO), indicated a reduced likelihood of a sudden eruption in Grindavík. Residents and businesses in Grindavík were then permitted to enter the area between 7:00 and 21:00 UTC to retrieve valuables, attend to their properties, and conduct business activities. However, the town remained closed to the general public and unauthorized traffic. Safety measures, including limited vehicle access with restriction on certain types of transportation, constraints on essential services and a prepared evacuation plan, were established. The area, under continuous surveillance, is still considered dangerous. Residents were advised to keep records of valuables taken and to contact their insurance companies, and to be cautious as houses might be unsafe. Following the town's evacuation, a state of emergency was declared with the onset of each subsequent eruption, highlighting the significant risk involved. Upon the conclusion of each eruption, the status was systematically reduced to Alert Phase. About 120–150 residents commute to work in the town each day.

Since the disaster in November, there have been several instances of disobedience by the residents of Grindavík. In December, a couple was caught staying at their home for several nights and were threatened with arrest due to the regulations in place at that time. On the first day of the May–June eruption, three residents of Grindavík refused to leave the town. The police did not use force as the evacuation was only an advisory from the authorities. However, the response teams later chose to evacuate, and the three individuals subsequently decided to leave as well since they were the only ones left in the town while the eruption was ongoing close by.

In the aftermath of the November disaster, the town was subjected to stringent regulations, which included specific opening and closing times. Authorities also created a live hazard assessment map for residents and others in the area, which is regularly updated to reflect the current situation. In late February, the State Commissioner of Police authorized near-unlimited access to the town, albeit with a clear emphasis on the fact that "residents and employees enter the town at their own risk". The chief of police further emphasized that Grindavík is ill-suited for children due to the absence of functioning schools, the compromised state of infrastructure, and possible hidden faults in the town. Access is still strictly limited to residents, employees, and authorized media personnel. While homeowners are permitted to stay overnight in their homes, the chief of police strongly advises against it. In the nights leading up to the March–May eruption, 5–10 homes were occupied.

To enhance the existing security measures, which involved sending SMS warning messages to residents in the zone, emergency warning sirens underwent testing prior to the March–May eruption. The warning sirens have not been sounded in Iceland since April 2000 after they were subsequently decommissioned. Instead of warning sirens, a dial-out system was developed for all mobile phones. The warning sirens were, among other things, decommissioned as they were considered expensive and unreliable in operation. The system currently comprises three sirens located in Grindavík, with additional sirens installed at the Svartsengi power station and the Blue Lagoon.

The main concern and risk in Grindavík currently comes from the extensive cracks and faults that have appeared, most of which formed during the subsidence in November. Some of these pre-existing cracks have expanded following subsequent eruptions, and additional new ones have also formed. Before the November event, authorities were cognizant of existing fissures; however, many structures and pieces of infrastructure were built over these old cracks, disregarding the potential for their reactivation after being dormant for more than 2,000 years. Specialists, including those from the Icelandic Road Administration, are actively monitoring and mapping both the newly formed and previously unknown or concealed cracks that could pose a risk to public safety. Their efforts involve the use of advanced tools such as drones and various geophysical survey instruments. On 10 January, an employee engaged in sealing these cracks fell into what was apparently the largest fault, which runs directly through the centre of the town.

The earthquakes in Grindavík had a profound impact on infrastructure and residences, prompting over 500 reports of property damage to the Natural Catastrophe Insurance of Iceland. Of these, at least 74 properties were deemed uninhabitable, with three being completely destroyed by direct lava contact. Two weeks following the earthquakes, a thorough damage assessment was initiated and is still ongoing. The estimated total cost of the damages was initially predicted to be up to ISK 10 billion () but is now expected to reach ISK 16 billion (). Grindavík's Planning and Environmental Department has estimated that over 60 buildings need to be demolished due to total loss from the November earthquakes. The affected structures include part of a nursing home, a recently renovated elementary school, and a gymnasium where the largest fissure had penetrated the inside football pitch. Additionally, there have been discussions about converting one of the affected buildings into a museum dedicated to the tragedies in Grindavík, highlighting the largest fault. Maintenance efforts to restore the town to an acceptable condition are projected to be completed in the first half of 2025, with the total cost of ISK 470 million () split between the state at ISK 440 million () and the municipality at ISK 30 million (). The goal is to eliminate the need for the three road closure gates that have been controlling all traffic into Grindavík since November 2023.

Prior to the Icelandic government's implementation of a law to purchase all residential properties in Grindavík, property owners facing irreparable damage to their homes were obligated to allocate a segment of their insurance compensation—earmarked primarily for on-site repairs or reconstruction—to cover a disposal fee. In cases where rebuilding at the original location was not permitted, property owners were then allowed to use their insurance proceeds to buy homes elsewhere. Since November 2023, the Icelandic government's total expenditure related to the natural disasters in Grindavík and the surrounding area is approaching ISK 100 billion ().

Blue Lagoon

The Blue Lagoon is currently open with operational hours subjected to adjustments based on forecasts of wind conditions and gas emissions, as well as any potential threats to nearby roads from volcanic activity. The hot springs area has repeatedly been closed and evacuated due to the earthquakes and eruptions. Although it has not been significantly damaged, lava has engulfed nearby roads, necessitating the construction of new ones. The hot springs were closed for three weeks after the beginning of the March–May eruption, due to their close proximity to the ongoing eruption nearby and the continuous release of toxic gases. The nearest lava front has halted and is currently less than away from the Blue Lagoon, which is protected by a constructed barrier.

The site's management announced the site's closure to visitors from 9 to 16 November as a precaution following the earthquakes. Rocks dislodged by the earthquakes were reported to have fallen onto roads in the area, and 30 guests left the resort following a magnitude 4.8 tremor in the early hours of 9 November. In addition to these safety concerns, the closure was also implemented to reduce increased stress on staff. The management has assured that all staff will receive their full salaries during the closure period. Furthermore, guests who were evacuated as a result of the tremor will be provided with a full refund. Helga Árnadóttir, Director of Sales, Operations and Services at the Blue Lagoon, confirmed that the seismic activity at Svartsengi caused no visible damage or structural impairment to their facilities. The buildings, designed for earthquake resilience, remained intact and structurally sound.

The administrators of the Blue Lagoon extended the closure announcement five times after the evacuation in November 2023 due to continuing geological activity. Following permission from the chief of police, it reopened on 17 December. Prior to reopening, the staff were trained in evacuation procedures to ensure preparedness for any emergencies, while the administration prepared an evacuation process, expected to take around two hours in case of emergency. Additionally, guests were to be informed about the current situation. Despite the advertised closure, staff members at the Blue Lagoon were observed staying in the spa's geothermal waters, apparently assessing them before the official reopening.

The Blue Lagoon remained open for just two days before it closed again on 18 December 2023 after the first eruption commenced only away. All guests and staff were evacuated from the site roughly one to two hours before the eruption. The Blue Lagoon reopened on 6 January, with all facilities back in operation by 10 January. However, it was shut down once again on 14 January and promptly evacuated, but reopened on 20 January. It was safely evacuated at the start of the 8 February eruption but the hot springs were subsequently cut off by a fast-moving lava flow engulfing the northest stretch of Route 426 (Norðurljósavegur), its main access road. On 16 February, the Blue Lagoon reopened after the Icelandic Road Administration constructed a new gravel road within the defence barriers surrounding the hot springs, restoring access that had been cut off by a lava flow from the recent eruption. The Blue Lagoon was temporarily closed and evacuated on 2 March in anticipation of an imminent eruption but reopened two days later after no eruption occurred. The Blue Lagoon was closed indefinitely from 16 March due to the onset of the fourth eruption, but it reopened on 6 April. During the fifth eruption, the Blue Lagoon was closed from 29 May to 2 June.

The chief of police states that maintaining operations at the Blue Lagoon is scarcely justifiable amidst the ongoing eruption due to the risk of air pollution compromising public health. Administrators, in consultation with authorities, regularly assessed whether it was safe to reopen the geothermal spa. On 20 March 2024, a staff member at the Blue Lagoon was hospitalized due to symptoms of gas poisoning amidst the eruption that began on 16 March, which had resulted in elevated levels of sulfur dioxide. The illness occurred while the employee was working at the hot springs. The worker is expected to make a full recovery.

In early August, firefighters initiated drills using newly acquired high-capacity fire hoses to apply geothermal water from the Blue Lagoon onto solidified lava. These hoses, procured at a cost of nearly ISK 500 million () from the United Kingdom, extend to about and discharge approximately , with a vertical reach of up to —substantially surpassing the previous system’s elevation. This sophisticated equipment was purchased following successful field trials conducted in late June, during which the application of water to active lava flows yielded promising results. In response to these outcomes, authorities opted to invest in this advanced water pumping technology. Additionally, the fire department established a new role, "Lava Cooling Systems Manager", to oversee the operation and maintenance of the specialized equipment.

Svartsengi power station

The Svartsengi power station was unoccupied and remotely controlled from the Reykjanes power station during the initial months following the November disaster. In 2024, the station was evacuated multiple times due to imminent eruptions and other perceived threats to staff safety. It experienced minimal impact from the earthquakes, with the only damage being "the interior furnishings and exterior walls, as well as considerable cracking in pathways and remote areas of the site". The power station continued to maintain its usual production levels of hot and cold water, as well as electricity. There is a risk that if lava engulfs the facility, approximately 30,000 residents on the peninsula, constituting about 8% of Iceland's population, would permanently lose essential heating and electricity. Construction of earth barriers began in November 2023, with the purpose of protecting the power station by redirecting future lava flows.

Before the January eruption, HS Orka, the operator of Svartsengi power station, introduced a novel early-warning system that may be a first in volcanic monitoring. This system issued an essential alert more than four hours before the eruption. Since November 2023, the boreholes, pre-dating their use in the advanced system, have been pivotal in predicting volcanic activities. Detecting pressure fluctuations, these boreholes have reliably signaled upcoming eruptions, demonstrating their pre-existing potential in volcanic surveillance and safety.

The eruption of 8 February produced a lava flow that came close to the power station. It cut off the northern access road to the geothermal plant (though the southern road was unaffected) and destroyed part of the Njarðvíkuræð pipeline supplying hot water from Svartsengi to Reykjanesbær, Suðurnesjabær, Vogar, and Grindavík. Around 20,000 people in the area were reported to have been cut off from the hot water supply. Residents of the peninsula were warned to use hot water and electricity sparingly. Keflavík Airport was among the locations affected by the loss of hot water; schools similarly affected were closed. Despite significant damage caused by the eruption on local infrastructure, the Capital Region was unaffected as it operates within a different geothermal energy distribution system. The Icelandic government declared a state of emergency in response to the hot water crisis. While the Reykjanes power station and the wider Icelandic grid can supply electricity if the Svartsengi line is cut off, the capability to deliver hot water, a critical function of the Svartsengi power station, cannot be replicated. At the time of the eruption, temperatures in the area reached as low as . The shortages contributed to the closure of schools, public pools and sport facilities in the area on 9 February.

The repair and reconnection of the hot water pipeline was completed on the afternoon of 9 February, approximately 30 hours after it was breached, restoring the supply of hot water to the wider Reykjanes area. Workers managed to splice together the undamaged sections of the old pipeline with the new underground system, often working through the night. In the weeks leading up to the February eruption, workers had been constructing an underground bypass pipeline parallel to an older one, designed to be more resistant to damage from lava flows. The plan was to link the intact section of the old pipeline, unaffected by the lava, to the new underground pipeline at both ends, outside the recently formed lava field. Despite these efforts, the newly constructed bypass pipeline collapsed under the pressure of the lava flow late evening on 9 February. Immediately workers started to construct a new pipeline, which was placed on top of the fresh lava. Around 50 hours later, on 12 February, water began flowing through the new pipeline. Lava from the May–June eruption came within of the power station's pipeline in the north. Authorities stated that they were prepared for the possibility of lava flowing over the pipeline, as it had been reinforced with soil fill.

The prospect of protecting the Njarðvíkuræð hot water pipe leading from the plant was considered extremely challenging, as it is situated above ground on stilts. Prior to the eruption in February, plans were established to bury a new underground bypass pipeline, shielding it from potential lava damage, and preparing it for potential connection to the ends of the old pipeline in the event of engulfment. The eruption on 8 February resulted in the destruction of a segment of the old pipeline just north of Svartsengi and the subsequent collapse of a section of the new underground bypass pipeline on 9 February. Svartsengislína power line had previously been protected with barriers around the base of the masts; when the same eruption encircled the structures, causing no damage. The same power line was severely damaged in the May–June eruption when several electricity poles caught fire due to the immense heat of the glowing lava. West of this zone, a guy-wire from a mast at a NATO telecommunications facility snapped due to the proximity of the same lava flow, posing a temporary threat to the station. A barrier had previously been constructed specifically to protect the telecommunications station.

In early summer 2024, a new geothermal well was discovered through a collaborative project involving HS Orka, ÍSOR, and the Department of Civil Protection and Emergency Management, under the leadership of the Ministry of the Environment, Energy, and Climate. This initiative was launched following an emergency in February of the same year when the entire Suðurnes Peninsula lost all hot water for several days due to lava flowing over the main pipeline from the Svartsengi power station to the towns. Prior to this event, authorities had no plans for identifying new backup boreholes. The new well was identified after test drilling in the area and delivers approximately of water at temperatures exceeding . It was found in the Rockville Zone, north of Keflavík Airport, where a United States Army radar station operated from 1953 to 1997 and has been abandoned since. Hailed as a breakthrough in energy security on the peninsula, authorities have already drilled three boreholes at distinct locations on the peninsula to find the best delivery spot, marking the first boreholes drilled in the area since the Svartsengi power station was established in the late 1970s. With this discovery, it is now possible to construct a new backup power station to supply hot water to the towns if the supply from the Svartsengi power station is disrupted again, or in the worst case, if the entire station is engulfed by an eruption. The new power plant is planned to be operational by the coming winter.

Barriers and roads

A strategic plan for the construction of protective barriers had been established well in advance of the recent seismic disturbances in the area. The commencement of this plan was placed on hold, as there was no pressing threat of a volcanic eruption, coupled with the significant environmental repercussions involved. However, on 10 November, due to escalating earthquake activity, a fleet of lorries began delivering materials to the predetermined site near the Blue Lagoon and Svartsengi power station. But this initial operation was soon put on hold owing to concerns about a potential eruption later that same day. The construction work was officially resumed on 13 November, following the Althing's approval of a bill proposed by then-Prime Minister Katrín Jakobsdóttir. Following this, workers began assembling filler materials into barriers at the planned sites. The construction of the barriers was almost complete when the 18 December eruption occurred. Once it was safe for workers to resume, they were quickly sent back to the site to finish the remaining filling work on the barriers.

Construction of protective barriers around Grindavík, for which plans were already in place prior to the eruptions, officially began on 2 January. The project, initiated from the eastern end, involved erecting a barrier extending over . The first phase of construction aimed to reach an average height of around , although this may vary in different locations. The design of the barrier, guided by lava flow simulations, specifically targeted the areas at highest risk. On 21 March, the advancing lava began to fill a stone quarry previously utilized for sourcing materials for the barriers. However, workers are still able to obtain materials from alternative locations. Additionally, recently solidified lava from the eruption was used as a resource for assembling the protective structures. In late March, authorities decided to raise the height of the barriers north-east of Grindavík in response to the thickening lava field from the March–May eruption, which posed a risk of overspill. Construction crews worked around the clock on the project. By the end of April 2024, lava began to creep over the same section of the barriers, though it posed no immediate threat. Protective barriers for the town of Vogar, located in the northern part of the peninsula, was for a time also under consideration after lava flow models indicated a chance of lava from the current eruption flowing north towards Route 41 (Reykjanesbraut) in the future.

Construction of another barrier commenced on 6 May, 2024, following approval from Justice Minister Guðrún Hafsteinsdóttir. This decision was made after she received a memorandum from the Department of Civil Protection and Emergency Management a week earlier. Initially intended to be the final initiative by the Icelandic government regarding the eruptive series in Sundhnúksgígar, the May–June eruption necessitated an additional protective barrier. This new barrier, located inside the perimeter of the existing barriers and closer to Grindavík, was designed to proactively safeguard against potential lava overflow, particularly in scenarios involving thin-flowing pāhoehoe lava. The structure stands high and extends between in length. A team of approximately 30 to 35 individuals worked day shifts on this project, completing the barrier in June.

On 14 January and 29 May, two separate lava flows engulfed Road 43 (Grindavíkurvegur) south of the Svartsengi power station and the Blue Lagoon. On 8 February, 17 March, and again on 8 June, different lava flows overtook the same road north of these landmarks. Route 426 (Norðurljósavegur) was first covered by lava on 8 February north of Svartsengi, and later on 29 May south of Svartsengi. On 29 May, Route 425 (Nesvegur) was overtaken by lava for the first time. In total, lava flowed over three different roads, five different sections, during four distinct eruptions, for a total of eight occurrences. These incidents effectively severed the most important exit from Grindavík to the northern peninsula each time, necessitating the construction of new gravel roads over the freshly cooled lava within days or weeks. In some instances, the road alignment needed to be adjusted.

In the early stages of the March–May eruption, the encroaching lava threatened Route 427 (Suðurstrandarvegur) as it amassed against the eastern protective barrier of the town and advanced towards the sea to the south. This put two of the three crucial roadways linking Grindavík at risk, sparing only Route 425 (Nesvegur). Concerns grew as there was a chance the lava would make it to the ocean near the road, potentially causing minor explosions and emitting toxic gases like hydrochloric acid (HCl) due to chemical reactions with the sea. A zone extending from the anticipated point of marine entry was deemed critically dangerous to human safety. However, these risks were allayed when the lava halted approximately from Route 427, just days after the eruption began. Since then, the lava front has remained unchanged.

In the largest eruption so far, the May–June eruption, lava flowed over three road sections on the day it began: Route 43 (Grindavíkurvegur) south of Svartsengi, the southernmost part of Route 426 (Norðurljósavegur), and for the first time, Route 425 (Nesvegur) just west of the town. On 8 June, ten days after the eruption started, lava also flowed over the northern part of Route 43. Moreover, the eruption threatened Route 427 (Suðurstrandarvegur) for a period of time. On the evening of 20 June, lava began to overspill a section of the barrier north-west of Sýlingarfell mountain after accumulating north and south of the protected Blue Lagoon and Svartsengi area. Before the overspill, workers had already begun efforts to stop or slow down the lava by bulldozing old soil over it and using at least three firefighting trucks along with equipment from Keflavík Airport and Grindavík to pump water via fire hoses, with "quite good results". This marks the first such lava mitigation attempt since the 1973 eruption in Heimaey. New roads were not constructed until the eruption ceased later in June. Most have already been rebuilt with base layers and gravel wearing courses over the newly solidified lava. The completion time of the project depended on the temperature of the lava.

In mid-June, authorities observed that the lava was nearing the top of the northern section of the Svartsengi barrier, which safeguards the power plant and the Blue Lagoon. Consequently, they decided to heighten the existing barriers, which have now reached a height of . However, as the lava began to breach these barriers, they resolved to construct a new one within the existing defence perimeter in the Svartsengi area to provide enhanced protection for these critical infrastructures. They also decided to close a geographical gap between Þorbjörn and the area surrounding Hagafell, as well as reinforce the existing barriers most at risk of lava overflow. While no longer active, the lava from the May–June eruption is currently about from the structures within the barriers, although there is no immediate danger at this time.

After the August–September eruption, it became clear that the lava field was fairly close to Route 41 (Reykjanesbraut), Iceland's critical road linking the capital Reykjavík to Keflavík International Airport. Volcanologist Þorvaldur Þórðarson has cautioned that a new eruption on the Reykjanes Peninsula could potentially result in lava reaching the Reykjanesbraut road within a few hours if it matches the intensity of recent eruptions. While no decisions have yet been made regarding the construction of protective barriers, plans are in place to safeguard the road if and when the lava flow threatens it. The closest lava flow is currently about from this vital infrastructure.

In response to these developments, the Icelandic government implemented a 0.008% additional property tax, levied on the fire insurance value of properties, to fund the construction of lava barriers on the Reykjanes Peninsula and safeguard local infrastructure from potential volcanic eruptions. The temporary tax, which is intended to last for three years, came into effect on 1 January 2024, and is projected to raise nearly ISK 1 billion () annually. The tax is scheduled to expire on 31 December 2026. The total allocated funds for all defence barriers amount to ISK 7 billion (). So far, ISK 5.5 billion () of this amount has been spent.

Injuries and fatalities

On 10 January, just before the second eruption, a worker went missing while finalizing the filling of Grindavík's largest fault, after the ground suddenly collapsed midway down the fissure, dragging the top fill and the worker into its depths. At the time of this incident, there were no witnesses present. A colleague, finding no one upon return, reported the disappearance, initiating a search. Despite utilizing 3D scanners and underwater drones in the fissure, which is deep with water found at , the worker was not located due to the fissure's treacherous confines. The search, which included up to 70 rescue workers from the Icelandic Association for Search and Rescue, was terminated on 12 January due to the hazardous conditions. Following the search, The Administration of Occupational Safety and Health opened an investigation into the incident. With the individual presumed deceased, this incident represents the first death in Iceland associated with a volcanic eruption since the Heimaey eruption in 1973.

On 20 March, an incident at the Blue Lagoon resulted in an employee suffering from gas poisoning, attributed to a substantial release of sulfur dioxide from the March–May eruption, which was about from the geothermal spa. Despite security personnel being equipped with portable gas meters and the existence of several fixed gas meters across the hot springs area, the specific area where the incident occurred lacked proper monitoring. The affected employee required hospitalization but is expected to make a full recovery. The incident prompted the Blue Lagoon management to undertake a comprehensive reassessment of the site's safety measures. In response to the situation, police were dispatched to inspect the facility.

On the night of 23 August, shortly after midnight, a hiker who had walked from Route 41 (Reykjanesbraut) to the eruption site fell into a small crack and broke his leg. He was later rescued by emergency personnel. Despite previous warnings from authorities emphasizing the dangers of walking in the area at night, many individuals—often tourists arriving from Keflavík Airport—continued to attempt the trek. Authorities had warned that navigating the area in complete darkness is "extremely difficult and dangerous" due to numerous rifts that are hard to detect. Additionally, the area is an old bomb practice site, containing numerous unexploded ordnance. In the immediate aftermath of the incident, authorities continued to patrol the area to prevent further injuries or even potential fatalities.

International media coverage and tourism

The recent volcanic eruptions on the Reykjanes Peninsula created a negative impact on tourism in Iceland due to misleading news coverage by foreign media. Foreign media outlets focused on the state of emergency declared in Grindavík, which gave the impression that the entire country was unsafe. This led to cancellations and a decrease in new bookings and prompted Business Iceland to correct misconceptions and promote Iceland as a safe and unique destination, producing a Q&A video in collaboration with the IMO, and launching a marketing campaign in December. Furthermore, Lilja Alfreðsdóttir, Minister of Culture and Business Affairs, allocated ISK 100 million () to a special marketing campaign. Lína Petra Þórarinsdóttir, Head of Tourism at Business Iceland, believes that the negative impact of the volcanic eruptions can be turned into a positive in the long term, with Iceland being promoted as a unique destination with a special natural environment.

Birgir Jónsson, serving as CEO of Play Airlines at the time, claimed that extensive international media coverage of the volcanic eruptions in Grindavík caused substantial financial damage to Icelandic tourism, costing billions of krónas (tens of millions of dollars), in lost revenue. He voiced concerns over the exaggerated portrayal by some foreign news outlets, using imagined headlines such as "Iceland on fire" and "Poison gas over Reykjavík" to illustrate how such depictions contribute to portraying an unnecessarily alarming image of Iceland. While there have indeed been reports from abroad of toxic gas moving towards the Capital Region, subsequent analyses show that the emissions from the eruptions posed no significant threat or toxicity to the area. Since November 2023, the Blue Lagoon has faced similar challenges, incurring losses of ISK 5 billion () due to frequent closures.

Jóhannes Þór Skúlason, Managing Director of the Icelandic Travel Industry Association, said the earthquakes and volcanic eruptions on the Reykjanes Peninsula negatively impacted tourist traffic during the holidays. This led to a decrease in visitors over Christmas and New Year after the coverage led people both to call off trips to Iceland and lower-than-expected demand in January and February 2024 compared to 2023. According to figures by Statistics Iceland, registered guest nights in January 2024 were 13% fewer than in January 2023, or 390,000 instead of 450,000. Bjarnheiður Hallsdóttir, chairman of the same association, attributed the decline in part to the changed attitude towards travelling to Iceland, including the media coverage of the earthquakes in Grindavík.

Reactions

In a televised address following the 14 January eruption, then-President Guðni Th. Jóhannesson said that "a daunting period of upheaval has begun on the Reykjanes Peninsula", but urged the need to continue taking "actions that are within our power", while "hope for as good an outcome as possible". He also urged citizens to "stand together and have compassion" for those displaced by the eruption. Then-Prime Minister Katrín Jakobsdóttir said the eruption was a "black day for all of Iceland", but added that "the sun will rise again", and expressed solidarity with those affected.

See also

* Geology of Reykjanes Peninsula
* List of earthquakes in 2023
* List of earthquakes in Iceland
* List of volcanic eruptions in Iceland

References

External links

Icelandic Meteorological Office
��Official website

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