1. Geological Natural Disasters Flashcards
(21 cards)
How does an effusive eruption occur?
It occurs when hot, runny basalt magma reaches the surface.
How does an explosive eruption occur?
occurs when cooler, more viscous
magma (such as andesite) reach the
surface
Does an effusive eruption flow downhill easily?
Yes
Does an explosive eruption flow downhill easily?
No
What boundary is common at an effusive eruption?
A divergent boundary
What boundary is common at an explosive eruption?
A convergent boundary
What does ground motion mean?
The Earth’s shake as the seismic
waves is released.
What does liquefaction mean?
Saturated or partially saturated soil at
or near the ground surface loses
strength in response to strong ground
shaking
What is a landslide?
A collapse of a mass of earth or rock
from a mountain or cliff
When does a tsunami occur?
Occur when displacement of the sea
floor displaces the water above it,
generating large waves
What is a flood?
A rising and overflowing of a body of water especially onto normally dry land.
What is an ash eruption?
An explosive
eruption occurs increasing the force of hot,
expanding gases violently enter the
atmosphere
What is a lava flow?
Streams of molten
rock that pour or
ooze from an
erupting vent.
What is a Lahar?
A mixture of volcanic material and water that
forms a mudflow.
What is Poisonous gas emissions
Varied mix of
gases in any
volcanic eruption
→ eg, sulfuric
acid, hydrogen
sulfide, hydrogen
chloride and
hydrogen bromide
What is a hazard?
A threat (natural or human) that has the POTENTIAL to cause loss of life, injury,
socio-economic disruption or environmental degradation
What are some hazards associated with Ash eruptions/falls?
Abrasive fine particles can
enter the lungs and irritate the
eyes of animals and humans
- Ash fall may smother plant
life, contaminate water,
reduce visibility and
accumulate on buildings,
causing them to collapse
What are some hazards associated with Lava flows?
Devastating effects on local
communities → burying,
crushing, or burning objects in
their paths
- Fires started
What are some hazards associated with Lahars?
Erodes life/objects in its path,
taking anything and everything
with it and gaining speed (up to
60km/h or more)
- Many volcanic deposits are
acidic and can affect soil and
river systems for many years
What are some hazards associated with Poisonous Gas Emissions?
Damaged eyes & mucous
membranes
- Carbon dioxide = global warming,
Sulphur dioxide = global cooling,
ozone destruction & polluted air
(volcanic smog)
- death
- can leak into the water
What is viscosity?
Viscosity is a measure of a fluid’s resistance to flow (opposite to fluidity).
