Volcanoes

Question 1

Different magma types

Answer 1

Basaltic- conservative, 0.5% gas content, 1160 degrees c, Iceland
Andesetic- destructive 7-8% gas content, 1000 degrees c, Andes

Question 2

Lahars

Answer 2

Mt Ruapehu erupted in 1945 which emptied Crater Lake and dammed it with tephra. Filled up with water again, before the tephra dam collapsed on December 24th, 1953. Lahar collapsed a bridge and the oncoming train was derailed, killing 151.

Question 3

Lava flows

Answer 3

Nyiragongo, Goma, 2002 - 100 killed and 20% of buildings damaged or destroyed. Evacuation did not happen

Question 4

Pyroclastic flow

Answer 4

Mt Unzen, 1991 - 12,000 were evacuated beforehand. Flowed 4.5km from the crater and swept through a volcano observatory, killing 43.

Question 5

Ash fallout

Answer 5

Eyjafjallajokull cost the aviation industry $1 billion in grounded flights.
Mt Ontake, 2014 - unexpected eruption produced an ash fallout which killed 63

Question 6

Nuees ardentes

Answer 6

Martinique, 1902 - Mt Pelee erupted and produced the nuees ardentes. Very little evacuation so 29,000 in St Pierre were killed, leaving just two survivors.

Question 7

Nyriagongo

Answer 7

100 died in 2002 as there were only 5 minutes for evacuation
Education programmes commenced- children in school can teach their families
Twice monthly trips up the volcano to monitor the lava lake
Aim for 3 weeks eruption notice
May 2021, erupted again, killing 32. The government urged people to evacuate but many did not adhere

Question 8

Prediction

Answer 8

Mt St Helens - used tiltmeters to predict and evacuate people in 1982
14 tiltmeters near Chances peak

Question 9

Protection

Answer 9

Earth walls used near Kilauea - lava flow in 1995 was diverted away from 2 plantations and the village of Mahaka by earth walls
Etna, 1992 - sprayed lava with water