Natural Hazards and Minimizing Damage
Earthquakes
Earthquakes (cont.)
Volcanoes
Tsunamis...and Volcanoes
100
What is a natural hazard?
Any extreme event caused by natural processes
100
What is a fault?
Faults are locations where two plates rub against each other.
100
When do earthquakes occur?
Earthquakes occur when plates that were stuck suddenly move (become unstuck).
100
How are volcanoes classified?
Dormant, extinct, or active
100
What are 2 ways a tsunami can form?
thrust earthquakes, underwater volcanoes, or landslides
200
Can natural hazards be prevented?
No
200
Would a strong earthquake have a high rating or a low rating on the Richter scale?
A high rating
200
What are seismic waves?
Seismic waves are the waves of energy that travel outwards from an earthquake.
200
What are 2 of the ways volcanoes can form?
-convergent boundaries -mid-ocean ridges -hotspots
200
How can an island chain be created from a hotspot?
The hotspot does not move, while the tectonic plate above it continues to move--as the plate moves the volcano moves farther away from the hotspot, with the hotspot creating new volcanoes
300
Can damage from natural hazards be reduced or prevented?
Yes
300
When plates suddenly move, what type of energy do they release?
Kinetic energy
300
Do P-waves or S-waves hit the epicenter first?
P-waves
300
What are at least 2 of the threats created by volcanoes?
lava poisonous gas rocks/debris pyroclastic flows
300
How does wave height change as a tsunami approaches land?
The wave slows down and grows bigger
400
What are dampers?
Dampers are large weights that hang from the tops of building. They help buildings to move less during an earthquake.
400
What is the difference between the hypocenter and the epicenter?
The hypocenter is the location within the Earth’s crust where an earthquake occurs. The epicenter is the location on the surface directly above an earthquake.
400
Describe the 3 different types of faults.
Strike slip: two plates move horizontally Normal: one plate moves downwards Thrust: one plate moves upwards
400
What is different about hotspots, compared to convergent boundaries and mid-ocean ridges?
Hotspots are located in the middle of tectonic plates (instead of at plate boundaries)
400
Why do volcanologists monitor the ground around volcanoes?
As volcanoes prepare to erupt, specific gases escape from the cracks into the atmosphere
500
What is base isolation?
A base isolation system separates a building from the ground. During an earthquake, the base isolators move with the earthquake while the building can remain still.
500
How does a seismograph work?
The seismograph is based firmly on the ground with a weight that hangs freely from the top, with an attached pen. The seismograph base moves with the earth during the earthquake, recording the movement.
500
When plates get stuck, what type of energy do they store?
Potential energy
500
Why do volcanologists monitor the seismic activity around volcanoes?
As magma pushes upwards, it sometimes causes the ground to swell, which can indicate that an eruption may occur soon.
500
What is one of the things that the DART buoy system does?
registers earthquake activity detects wave height collects data on possible tsunamis transfers the information to a warning center
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