This text was initially featured on The Conversation.
Fountains of lava erupted from the Sundhnúkur volcanic system in southwest Iceland on Jan. 14, 2024. Because the world watched on webcams and social media, lava flows reduce off roads and bubbled from a brand new fissure that invaded the outskirts of the coastal city of Grindavík, burning down a minimum of three homes of their path.
Close by, development autos that had been working for weeks to build large earthen dams and berms in an try to divert the lava’s move needed to pull again.
People have tried some ways to cease lava previously, from trying to freeze it in place by cooling it with sea water, to utilizing explosives to disrupt its provide, to constructing earthen obstacles.
It’s too quickly to say if Iceland’s earthworks will reach saving Grindavík, a city of about 3,500 residents, and a close-by geothermal power plant. As a volcanologist, I comply with these strategies. Essentially the most profitable makes an attempt to cease or reroute lava have concerned diversions like Iceland’s.
Why lava is so exhausting to cease
Lava is a sluggish, viscous fluid that behaves considerably like tar. It’s topic to gravity, so like different fluids, it is going to move downslope alongside a path of steepest descent.
With the temperature of its molten rock typically well above 2,000 degrees Fahrenheit (1,000 Celsius), not a lot can stand in its means.
Freezing lava in its tracks
In 1973, Icelanders tried the most famous “lava freezing” experiment. They used water hoses from a flotilla of small boats and fishing vessels to guard the small island group of Heimaey from the Eldfell volcano’s lava.
The lava flows had been threatening to shut off the harbor, which is vital to the area’s fishing trade and a lifeline to the Icelandic mainland. The eruption ended earlier than the success of the technique might be correctly evaluated, however the harbor survived.
Combating lava with explosives
Hawaiians used explosives dropped from planes in 1935 and 1942 to attempt to disrupt lava flows from Mauna Loa volcano that had been threatening the city of Hilo on the Large Island.
The concept was to disrupt the channels or lava tubes within the volcano that had been supplying lava to the floor. Neither try was profitable. The explosions created new channels, however the newly shaped lava flows quickly rejoined the original lava channel.
Lava obstacles and diversions
Most up-to-date efforts have centered as a substitute on a 3rd technique: constructing dams or ditches in an try to divert the lava’s move towards a distinct path of steepest descent, into a distinct “lavashed,” a concept similar to a watershed however the place lava would naturally move.
Outcomes have been blended, however diversion might be profitable if the lava move might be clearly diverted into a definite space the place lava would naturally move–with out threatening a distinct group within the course of.
Many makes an attempt to divert lava have failed, nonetheless. Boundaries in-built Italy to stop Mt. Etna’s lava flows in 1992 slowed the move, however the lava eventually overtopped each one.
Iceland’s diversion efforts
Icelandic authorities evacuated Grindavík’s residents in November 2023 after swarms of earthquakes indicated a reactivation of the close by volcanic system.
Shortly afterward, development started on protecting obstacles for the city and a few close by vital infrastructure–notably, the Svartsengi geothermal energy station. Development needed to be placed on maintain in mid-December, when a first volcanic eruption occurred about 2.5 miles northeast of Grindavík, however work resumed in January. Work was nonetheless underway when magma reached the floor once more on Jan. 14.
Diverting lava on this area is troublesome, partially as a result of the land round Grindavík is comparatively flat. That makes it tougher to establish a transparent various path of steepest descent for redirecting the lava.
Icelandic officials reported on Jan. 15 that many of the lava from the primary fissure had flowed alongside the skin the barrier, nonetheless a new fissure had additionally opened contained in the perimeter, sending lava right into a neighborhood. Sadly, that means that Grindavík stays in danger.
Disclosure: Loÿc Vanderkluysen receives funding from the Nationwide Science Basis.
