Volcano Case Studies

Question 1

Mt Saint Helens
Washington State
1980

Answer 1

Type: Pyroclastic Flow
Plate Boundary: Destructive - Oceanic and Continental

Violent and Explosive Lahars
Silica Rich Lava- Thick
Gases trapped by the thick lava made it explosive
Plume of Ash

Predicted:
Volcano changed shape
It was emitting gas
Lots of small earthquakes

Question 2

Mt Ontake
Japan
2014

Answer 2

Type: Phreatic Eruption - Steam Driven Explosions
Plate Boundary: Destructive - Oceanic (Pacific) and Continental (Eurasian)

Strato Volcano
Silica Rich Lava - Thick but no Lava Flow
Steam, Ash, Volcanic Bombs
Violent Pyroclastic Flow

Not Predicted;
No evidence of ground heating or change in ground shape
No gases being emitted
63 died

Question 3

Mt Kilauea
Hawaii
2020

Answer 3

Type: Mild Lava Flow
Plate Boundary: Hotspot

Shield Volcano
Basaltic Lava- low silica making it runny but slow due to shallow relief of land

Predicted:
The volcano had been active from 2008-2018

Question 4

Lake Nyos
Cameroon
West Africa
1986

(Silent Killer)

Answer 4

Type: Gas Eruption
Plate Boundary: Intraplate - Hotspot

Strato/Composite Volcano
Silica Rich Magma
Volcanic Gases Dissolved into the Lake
Cloud of CO2 lifted from the lake in the night

Not Predicted:
CO2 cloud came from nowhere
Engulfed and entire village
Killed around 2,000 residents

Question 5

Lake Nyrigongo
Congo
2002

Answer 5

Type: Released Gases, Lava
Plate Boundary: Hotspot Over Mantle Plume

Strato/Composite Volcano
Low Silica Content- runny and quick lava

Not Predicted:
170 died