Positive and Negative Effects Flashcards
What are the positive effects of volcanic eruption?
1) Bring out special minerals
2) Source of geothermal energy
3) Increase the fertility of the soil
4) Volcano Tourism
5) Premium building materials
What are the negative effects of volcanic eruption?
1) Can have significant effect on climate
2) Lead to economic loses
3) Loss of life
4) Health eruption
What are indirect/secondary effects of volcanic eruption?
1) lahar
2) tsunamis
How are people warned of volcanic eruptions?
alert levels (0-5)
How many alert levels are there?
6 signals
How are alert levels are determined?
- Ash cloud (greyish isn’t normal)
- Volcanic erathquakes
- Release of gases
- Evaporation and ashing
- Swelling of volcano (reqs special instruments)
SIGNS OF AN IMPENDING VOLCANIC ERUPTION
Volcanic quakes
Steaming activity
Temperature of hot springs
Drying up of vegetation
Crater glow
Ground swells
Localized landslides
Chemical content of springs
5 types of volcanic hazards
1) PYROCLASTIC DENSITY CURRENT (PDC)
2) LAVA FLOW
3) ASHFALL OR TEPHRA FALL
4) LAHAR
5) VOLCANIC GASES
Denser ,therefore this is a ground-hugging current
Most dangerous type of volcanic flow
Forms when ash and dust race down the sides of a volcano like a river
Can be as hot as 700 C and can move at 200 km/h
Can bury and destroy everything in its path
PYROCLASTIC DENSITY CURRENTS (PDCs)
- river-like flow of lava that can bury anything on its path
Lava Flow
- Rapidly flowing thick mixture of volcanic materials and water
- After eruption there is deposits still sitting on top of the volcano & where there is a storm it will carry
LAHAR
- fall of ash in plentiful amounts with its quantity variance based on the direction of the wind
- possess respiratory problems
ASHFALL OR TEPHRA FALL
gases from the volcano consisting of:
water vapor
hydrogen sulfide
sulfide dioxide
carbon monoxide
hydrogen chloride
hydrogen fluoride
volcanic grases
