Read the BBC news article about trying to stop or divert a flow of lava.
- Why is it difficult to stop a lava flow?
- Name three locations where people have attempted to stop or divert a lava flow.
- List four methods people have used to stop or divert a lava flow.
- Which of the methods do you think has been the most successful?
- Explain one of the methods.
- Although relatively slow moving, the path of the lava flow is ‘notoriously hard to predict.’ With temperatures of about 1,000°C, the ‘lava destroys whatever it touches.’
- Lava flows have been diverted or stopped at the following locations:
- The city of Hilo, Hawaii, USA – In 1935 from the Mauna Loa volcano.
- The villages of Catania and Paterno, Sicily, Italy – In 1669 from the Mount Etna volcano.
- The town of Vestmannaeyjar on the island of Haimey, Iceland – In 1973 from the Eldfell volcano.
- Three towns on the slopes of Mount Etna, Sicily, Italy – In 1983 from the Mount Etna volcano.
- The town of Zafferana, Sicily, Italy – In 1992 (not given in the article) from the Mount Etna volcano.
- The four methods used have been:
- Bomb it.
- Cool it with water.
- Build a barrier.
- Add concrete (blocks).
- Students will choose one method and explain its effectiveness. They should note that the US Geological Survey suggests that the Iceland and Etna diversions "may not have succeeded had their respective eruptions continued."
- The rationale for the four methods:
- Bomb it – to attempt to destroy the lava tubes, slow the lava flow and allow it to solidify. See why-would-you-ever-bomb-a-volcano?
- Cool it with water – to solidify the leading edge of the lava flow.
- Build a barrier – to slow the lava flow and direct it away from habitation.
- Add concrete (blocks) – to attempt to divert the lava flow. This method used near Zafferana also included the excavation of an artificial trench to catch lava redirected from a breach made with explosives.