One Note - volcanic hazards Flashcards
1
Q
what are the features of a lahar?
A
mudflows
- It is a secondary effect - Mixture of water and rock fragments flowing down the slopes of a volcano or river valley - More destructive than normal flood - Large amount of rock and ash - Quickly forming - Major cause of death in volcanic eruptions as they can travel very far as it could flow through a river valley unlike pyroclastic flows - Common cause is heavy rain - Can happen after or a lot after an eruption - Evacuation is the only option - Hiding in buildings is not a protective measure
2
Q
what was the eruption that caused an enormous lahar?
A
nevada del ruiz
3
Q
when was the nevada del ruiz eruption?
A
novermber 13th 1985
4
Q
how many deaths did the nevada del ruiz eruption cause by burying the town or armero in tolima?
A
25,000
5
Q
what are the features of ash fall?
A
- Volcanic ash is very sharp.
- Collapses roofs.
- Brings down power lines.
- Kills plants.
- Contaminates water supplies.
- Respiratory hazard. Breathing it in can cause you to inhale the sharp ash and this can cut up your lungs causing you to drown in your own blood. Can cause the disease silicosis.
6
Q
what are the features of lava flow?
A
- High temperatures
- Generally flow moving and less catastrophic than pyroclastic flows
- Basaltic is the most dangerous as its runny
7
Q
where is the largest lava lake in the world?
A
Mt Nyiragongo
DRC
8
Q
how often does Mt Nyiragongo have seismic activity?
A
every 4 minutes so scientists work 24/7 all year round
9
Q
how many people lost their lives in 2002 due to Mt Nyiragongo?
A
90,000
10
Q
what mentality do the people in the area of Mt Nyiragongo have?
A
fatalism
