Volcano Watch – Iceland’s recent eruption a reminder of lava flow hazards

Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.

Lava flows slowly approaching houses. Authorities evacuating neighborhoods. The tension of residents not knowing when, or if, they can return to their homes.

These scenes may bring up difficult memories for Island of Hawaiʻi residents whose lives were affected by the destructive 2018 eruption of Kīlauea. During the four months of that eruption on the lower East Rift Zone, hundreds of homes were destroyed, and thousands of lives were disrupted.

But this scenario also occurred just this month, in Iceland. A new eruption on the Reykjanes Peninsula began on Jan. 14, threatening the small fishing village of Grindavik. Fissures opened just a few hundred yards upslope of the town, sending a lava flow into residential areas. The flow inched into the edge of town and destroyed several houses.

By the next day, the flow front had stalled, and the eruption was ending. But the magmatic system has been reinflating beneath the surface, indicating another eruption could happen in the near future.

This isn’t the first time that Iceland has dealt with destructive lava flows. In 1973, an eruption sent lava through the village on the island of Heimaey, with lava creeping into the nearby bay. That eruption was, perhaps, most notable for the use of water cannons to try to cool the flow and arrest its advance before it blocked the entrance to the fishing harbor.

Nearly half of the town was destroyed and today, a house “graveyard” is present on the surface of the 1973 lava flow that covered the town, with stone markers showing the location of each owner’s house accompanied by a small sketch of the residence.

The eruption this month in Iceland hasn’t been the only recent eruptive activity there. Over the last three years, five different eruptions have occurred on the Reykjanes Peninsula. Most of these have been a safe distance from residential areas. Thousands of tourists were drawn to the up-close views of spectacular lava fountaining.

Unfortunately, the geologic record suggests that more eruptions could occur in the near future on the peninsula. The last eruptive phase in this part of Iceland occurred 800 years ago, but eruptive phases have lasted decades or longer. This suggests that the past five eruptions may be just the start of activity that could persist for years. This no doubt adds to the anxiety of Grindavik residents.

In a way, this recurrent eruptive phase in the Reykjanes Peninsula is reminiscent of the current era that we see at Kīlauea. The summit caldera at Kīlauea has been in a multi-year phase of crater refilling, following the collapse and subsidence of the caldera floor during the 2018 eruption. Five eruptions have occurred since 2020.

However, at Kīlauea, we have been fortunate that this multi-year eruptive phase has been safely contained within the summit caldera, with no threat to residential areas. USGS Hawaiian Volcano Observatory scientists keep a close eye on the monitoring data, particularly for any signs of magma migrating into the East Rift Zone.

The Iceland and 2018 Kīlauea eruptions are just two of several recent examples that highlight the destructive nature of lava flows. In 2021, the eruption of Cumbre Vieja, in the Canary Islands, produced lava fountains and flows that reached the ocean, cutting through residential areas and destroying over a thousand buildings.

Earlier that same year, a flank eruption of Nyiragongo volcano, in the Democratic Republic of the Congo, sent lava flows through several villages, destroying about a thousand homes and killing 32 people. Thousands of residents were displaced.

In each of these places—on the Reykjanes Peninsula, Kīlauea in 2018, Cumbre Vieja, and Nyiragongo—the impact of the eruption extends far beyond the margins of the lava flow. Large numbers of nearby residents have been displaced, and their lives severely disrupted, even if the flow spared their property.

Residents and communities take time to adjust to a changed landscape. The effects of the lava flows can linger for years after the eruption ends.

While advances in monitoring and forecasting of eruptive activity have improved our ability to provide warning to stakeholders before an eruption; residential areas around the world are still vulnerable. Whether it’s been 800 years or 5 years since the last eruption where you live, it’s important to know the volcanic hazards that could impact you and make a plan for taking care of yourself, your family, and your property.

Volcano Activity Updates

Kīlauea is not erupting. Its USGS Volcano Alert level is advisory.

Earthquake activity in Kīlauea summit region remained low over the past week, while summit tilt shows continuing inflation. Unrest over the past several months has fluctuated and eruptive activity could occur in the near future with little or no warning. The most recent sulfur dioxide (SO2) emission rate for the summit—approximately 70 tonnes per day—was measured on January 17. No unusual activity has been noted along the rift zones.

Mauna Loa is not erupting. Its USGS Volcano Alert Level is at normal.

Webcams show no signs of activity on Mauna Loa. Summit seismicity has remained at low levels over the past month. Ground deformation indicates continuing slow inflation as magma replenishes the reservoir system following the 2022 eruption. SO2 emission rates are at background levels.

Three earthquakes were reported felt in the Hawaiian Islands during the past week: a M3.0 earthquake 4 miles east-northeast of Hōnaunau-Napo‘opo‘o at 4 miles depth on Jan. 22 at 5:41 a.m., a M2.7 earthquake 14 miles southeast of Waikōloa at 19 miles depth on Jan. 19 at 8:04 p.m., and a M3.4 earthquake 12 miles west of Kailua-Kona at 5 miles depth on Jan. 18 at 2:54 p.m.

HVO continues to closely monitor Kīlauea and Mauna Loa.

Visit HVO’s website for past Volcano Watch articles, Kīlauea and Mauna Loa updates, volcano photos, maps, recent earthquake information, and more. Email questions to askHVO@usgs.gov.