How realistic is its physical geography in Volcano (1997)?
Hollywood disaster movies are a popular genre of film. This article will explore the realism of the scenes shown in the film Volcano, which was produced in 1997, look into the different types of volcanoes, the formation of volcanoes, where they are usually found and will also talk about few case studies of volcanic eruptions around the world.
Volcano (1997 film)
What are volcanoes?
There are a few types of volcanoes, but the main types are shield volcanoes, cinder cone volcanoes and composite volcanoes. Volcanoes can be split into three categories: active (erupts frequently), dormant (temporarily inactive but not extinct) and extinct (never likely to erupt again).
Shield volcanoes are formed by easy flowing lava (lava with a low viscosity), which is why it has a broad profile - caused by lava flow building up over time. Many of the largest volcanoes on Earth are shield volcanoes, including Mauna Loa in Hawaii.
Cinder Cone Volcanoes
They have a cone-shaped peak, a crater and steeply angled sides, and are most likely found near other volcanoes. Its eruptions are much smaller compared to other types of volcanoes, and fragments called scoria or cinders (melted rocks filled with gas) are sprayed out during the eruption.
Composite volcanoes are also known at stratovolcanoes and they are much more explosive than shield volcanoes. The magma of composite volcanoes contain more silica than that of a shield volcano, which makes it more viscous, resulting in a more dangerous eruption.
Cinder Cone Volcanoes
How are volcanoes formed?
- Magma rises through cracks of the Earth's crust.
- Pressure builds up inside the Earth and the pressure is released eg. due to the movement of tectonic plates, causing an eruption.
- The lava from the eruption cools down and forms the new crust.
- Over time, after more eruptions, the rock builds up and a volcano forms.
Where do volcanoes usually form and why?
Below is a map of the world with black lines separating each tectonic plate and red dots representing the volcanoes formed.
Volcano (1997 film) VS Reality
Geographical location of Los Angeles
Rocks tend to melt more when one plate slide under another, and this kind of activity happens further north in Oregon and northern California, which is why there are more active volcanoes there. Los Angeles and southern parts of California might suffer from a lot of earthquakes (as it is close to the San Andreas Fault), but are not likely to be affected by volcanic eruptions as it isn't near or on any fault lines or tectonic boundary lines.
Geographical location of Mt. Nyiragongo
Mt. Nyiragongo is an active composite volcano and its main crater is about 2km wide and usually contains a lava lake. Its lava lakes had been the most voluminous and the maximum elevation of the lake has been recorded to be about 3250m.
Volcanic eruptions in the area is usually caused by the split of the Earth's crust where two parts of the African plate break apart. The area is also a volcanic hot spot, which is also responsible for the numerous amounts of eruptions. A hotspot is a region than constantly experiences volcanic activity, where lava pushes up from under the mantle to create a volcano, generally caused by rising mantle plume.
The lava from Mt. Nyiragongo is made up of melilite mephelinite, which is a type of rock rich in alkali, resulting in the lava being a fluid. By being unusually fluid and its extremely low silica content, the lava flow of Mt. Nyoragongo moves extremely fast - it could go up to 100km/hr.
Shown on the picture on the right are the African plates and fault lines. Mt. Nyiragongo is right on top of a fault line, explaining its great and constant volcanic activities.
Volcanic Eruption Case Study
Volcanic eruption: Nyiragongo (Active Volcano)
- Many homes and land were destroyed by the sudden eruption of ash and lava
- 45 people died in the first 24 hour of the eruption
- The lava flow caused blockage of roads and stopped people from reaching particular areas in the city
- The eruption caused the spread of cholera due to the lack of hygiene and sanitation
- 14 villages were destroyed
- Around 50 people were killed due to the explosion of fuel
- 350,000 people in Goma were dependant on aid provided by other countries one month after the eruption
- Many people lost their businesses and jobs
- Aviation fuel stores exploded when the lava flow destroyed the airport
- Lava covered 15% of the city and destroyed 30% of Goma
- If the lava had reached Lake Kivu, carbon dioxide and methane could be release from the floor of the lake
Analysis and Comparison between the Film and Case Study
Effect of the eruption: Film VS Case study
- Buildings and train stations were destroyed
- Many people were injured and/or died
- Traffic accidents on the roads
- Explosions caused by lava bombs
- Buildings, vehicles, people caught on fire due to lava bombs
- Blockage of roads due buildings and vehicles on fire and lava flowing
Mt. Nyiragongo eruption:
The eruption of Mt. Nyiragongo caused various social, economical and environmental problems to the city of Goma. The effects include people being injured, loss of businesses and jobs, damage of land etc. A more detailed list mentioned above.
Accuracy of the effects of the eruption in the film:
It was shown pretty accurately as there were damaged buildings, train stations and severely injured people in the scenes of the eruption, but there were lava bomb and lightning in a few scenes of the eruption.
"Volcanic bombs are known to occasionally explode from internal gas pressure as they cool, but contrary to some claims in popular culture (specifically, the 1997 film Volcano), explosions are rare; in most cases most of the damage they cause is from impact, or subsequent fire damage. Bomb explosions are most often observed in 'bread-crust' type bombs." - quoted from https://en.wikipedia.org/wiki/Volcanic_bomb
How does the film differ from reality?
Conclusion (Summary of Comparison)
- Volcanic eruptions are unlikely to happen in Los Angeles.
- If a volcanic eruption actually happened in Los Angeles, the type of lava would be AA lava. (A picture of AA lava shown on the right).
- The lava on the movie can't be classified as any type of lava - it doesn't fit the characteristics of AA lava or pahoehoe lava (the only type of lava left is pillow lava, which is pillow-shaped and are associated with underwater extrusions of lava).
Although there were a few realistic aspects to the film, including:
- The eruption caused chaos on the streets.
- People died and were injured.
- Homes and buildings were destroyed.
- Some volcanoes do spurt out hot sulphurous gas through the fumarole.
The film could be a lot more realistic if the type of lava was created so that it looked like AA lava and the setting of the film was a country that has frequent volcano activity (for example, a country close to or on a fault line so that volcanic activity happening there would be a lot more convincing).