The Lack of Volcano Physics in The Movies

For nearly half a century, volcanoes have constantly been misrepresented in cinema. Whether as a stage for a climactic battle, an evil lair for dark antagonist, or a threatening obstacle in nearly any disaster movie, these burning mountains have been repetitively used as ominous symbols of danger and power. Almost no account is taken of their physics or how they work in the real world besides shooting out smoke and lava.

Common examples of flaws, however, have to do with how volcanoes erupt and affect the environment and living beings, such as the heat of the magma, density and speed of the lava, and pressure that precedes an eruption. These concepts are often ignored in fantasy films like Lord of the Rings (2001-2003), or more commonly in disaster movies such as Volcano or Dante’s Peak (1997). Ironically, disaster movies probably have the most flaws concerning volcanoes, even though the films’ plots revolve entirely around them.

One of the most stereotypical misconceptions about volcanoes is the idea that they are always tall mountains that explode with giant clouds of ash while also flooding the land with lava. In reality, volcanoes can only either send out explosions of ash (also known as pyroclastic clouds) or spew out flows of molten rock, but not both. Contrary to belief, the clouds are more dangerous than lava. The reason is the consistency of the magma. The amount of silicon determines whether the magma will solidify enough to build up or liquefy enough to flow. Tall mountains, called stratovolcanoes, are made with magma so high in silicon that it blocks the gases from escaping, causing huge amounts of pressure to build up. When stratovolcanoes eventually erupt, they finally release the gases and ash with tremendous force and speed, but no lava is present because it was too busy hardening into rock and holding back the gases. Shield volcanoes, however, are the type that sends molten rock flowing into the environment. Their deficiencies in silicon allow for huge lava currents coming out of short flat hills, but no ominous mountain peaks are created.

Despite this, these characteristics are always generalized and mixed together in order for the volcano to be more massive and epic in its destruction. This is most prominent in the movie Dante’s Peak. The 110-minute film features everything that can go wrong with a volcano, including earthquakes, pyroclastic clouds, ash storms, lahars, acidic waters, meteor-like rock debris and lava flows. While a pyroclastic flow makes for a climactic and believable climax in the end, lava floods bring up some criticism. There is a scene in the movie where the protagonists and their children go to a cabin to rescue their grandma from the eruption of the titular mountain. As they are leaving the cabin, magma immediately burns through the back wall and floods the living room within seconds. Since the peak is a stratovolcano, there shouldn’t be any magma flows at all, let alone lava that travels at fast speed.

Mount Doom from the Lord of the Rings trilogy also makes a blatant stereotype out of having every volcanic trope packed into one event. Besides generalizing mafic and felsic lava, however, there is a scene in the final movie, Return of the King, which incorrectly visualizes the density of lava. As a result of the climactic battle between the hobbit, Frodo, and malignant creature, Gollum, over the One Ring, Gollum ends up falling and splashing into a lava river with the ring. Gollum sinks into the molten rock in a matter of six seconds, and the ring manages to float on a piece of lava crust for a full minute. The viscosity of lava is nearly three times that of water, and a human being would not be able to sink into a pool of it unless that person was more dense than metal. In reality, Gollum would have just burned, and the ring should have sunk first.

As far as how living beings interact with magma, Mick Jackson’s disaster film, Volcano, has one of the most ludicrous examples. While the concept of a hotspot located under Los Angeles is hilarious, the heat of lava is misrepresented when metro official, Olber, goes into a subway to save train passengers from being engulfed in molten rock. While standing on the end of the train car, the lava has already seeped underneath it and is impossible to jump over. Olber decides to sacrifice himself by jumping into the lava and throwing the passenger over to the safe zone, while he quickly melts into the magma. Human bodies cannot melt into lava, but can only burn. The heat of lava cannot allow a body to change its viscosity and sink into a flow only a foot high. Olber should have been suffering from the heat on the train even when he wasn’t in contact with it.

All things considered, volcanoes cinematically suffer from these repetitive stereotypes and nonsensical heat physics. Lava is too dense and too slow for anything to be swallowed by it, and different volcanoes have various effects rather than just smoke clouds and lava currents. Producers and directors need to put more time and effort into studying how volcanoes work rather than the visual/simulation effects department.