This article was initially featured on The Conversation.
Fountains of lava erupted from the Sundhnúkur volcanic system in southwest Iceland on Jan. 14, 2024. As 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 at the least three homes of their path.
Nearby, building autos that had been working for weeks to construct massive earthen dams and berms in an try to divert the lava’s movement had to pull again.
Humans have tried some ways to stop lava up to now, from trying to freeze it in place by cooling it with sea water, to utilizing explosives to disrupt its provide, to constructing earthen limitations.
It’s too quickly to say if Iceland’s earthworks will achieve saving Grindavík, a city of about 3,500 residents, and a close-by geothermal energy plant. As a volcanologist, I observe these strategies. The most profitable makes an attempt to stop or reroute lava have concerned diversions like Iceland’s.
Why lava is so hard to stop
Lava is a sluggish, viscous fluid that behaves considerably like tar. It is topic to gravity, so like different fluids, it’s going to movement downslope alongside a path of steepest descent.
With the temperature of its molten rock usually nicely above 2,000 levels Fahrenheit (1,000 Celsius), not a lot can stand in its means.
Freezing lava in its tracks
In 1973, Icelanders tried the most well-known “lava freezing” experiment. They used water hoses from a flotilla of small boats and fishing vessels to defend 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 crucial to the area’s fishing trade and a lifeline to the Icelandic mainland. The eruption ended earlier than the success of the technique could possibly be correctly evaluated, however the harbor survived.
Fighting 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 Big Island.
The thought 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 unique lava channel.
Lava limitations and diversions
Most latest efforts have targeted as a substitute on a 3rd technique: constructing dams or ditches in an try to divert the lava’s movement towards a distinct path of steepest descent, into a distinct “lavashed,” a idea comparable to a watershed however the place lava would naturally movement.
Results have been blended, however diversion could be profitable if the lava movement could be clearly diverted into a definite space the place lava would naturally movement–with out threatening a distinct group within the course of.
Many makes an attempt to divert lava have failed, nevertheless. Barriers inbuilt Italy to stop Mt. Etna’s lava flows in 1992 slowed the movement, however the lava finally overtopped every 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, building started on protecting limitations for the city and a few close by crucial infrastructure–notably, the Svartsengi geothermal energy station. Construction had 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 officers reported on Jan. 15 that a lot of the lava from the primary fissure had flowed alongside the skin the barrier, nevertheless a new fissure had additionally opened contained in the perimeter, sending lava right into a neighborhood. Unfortunately, that suggests that Grindavík stays in danger.
Disclosure: Loÿc Vanderkluysen receives funding from the National Science Foundation.