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Science Ch. 6 and 7 Study Guide
1.
What kind of damage can volcanic ash cause?
Volcanic ash can contaminate the water supply, bury plants
and animals, cause structural damage, and mix with water and
form lahar.
2.
What is a pyroclastic flow?
A rapidly moving mixture of hot gases and solids
3.
What is a fracture surface along which rocks can slip called?
A fault
4.
Elastic strain directly causes ___________________.
Earthquakes
5.
What is lahar and why is it dangerous?
It is a rapidly moving mixture (made up of volcanic ash and water) that
can travel downhill up to 10 meters per second. It can bury human and
wildlife habitats.
6.
Describe a cinder cone volcano.
It is steep-sided, composed of basaltic lava, and develops from layers of
tephra.
7.
Where do most earthquakes occur?
On or near Earth’s plate boundaries.
8.
Describe a shield volcano.
Gradual slopes, and built out of layers of gently flowing
basaltic lava.
9.
If the magma of a volcano has a high amount of dissolved gas in the
magma (such as water vapor, carbon dioxide, sulfur dioxide, and
hydrogen sulfide)
then the volcano is more likely to erupt ________________________.
Explosively
10.
There
are
volcanoes
on
_______________________.
the
Hawaiian
Islands
because
They are near a hot spot.
11.
Know the drawings on page 253.
12.
True or false. A surface wave travels fastest. (If false, which kind of
wave does travel the fastest?
False. A P wave travels fastest.
13.
Which type of wave cannot travel through liquids (but can travel through
solids)?
Secondary waves
14.
Why does magma form in the rifts when tectonic plates separate?
Because the magma rises to fill the space between the
separating tectonic plates through fissure eruptions.
15.
Define the term “vent”.
The central, circular, or oval-shaped opening of a volcano from
which magma erupts
16.
When a seismograph that is far away from an epicenter records an
earthquake, the P waves would arrive (earlier/later) than the S-waves.
(earlier)
17.
Where do island arc volcanoes form?
Where two oceanic plates converge
18.
Why are there so many volcanoes near the Ring of Fire?
There are tectonic plate boundaries at many locations near the
Ring of Fire.
19.
Where are most volcanoes located?
Along plate boundaries
20.
Why does magma rise toward the surface of the Earth?
It is less dense and more buoyant than surrounding rock.
21.
Which type of seismic wave travels fastest through rock?
P waves.
22.
Which type of seismic wave causes the most damage?
Surface wave
23.
What is a seismograph?
An instrument used to record seismic waves/magnitude of
earthquakes.
24.
What is an epicenter?
The point on the Earth’s surface directly above the
earthquake’s focus.
25.
What is a tsunami?
A seismic sea wave
26.
True or false. At least three seismograph recordings are needed to locate
the epicenter of an earthquake.
True.
27.
How much stronger is an earthquake with a magnitude of 3.0 than an
earthquake with a 2.0 magnitude?
About 30 times stronger
28.
What is the Moment Magnitude Scale based on?
The amount of energy released during an earthquake
29.
What is lava?
Magma that rises to Earth’s surface
30.
Name the most common hazard that can occur after an earthquake.
Fires caused by ruptured gas or electrical lines
31.
What is liquefaction?
The process by which shaking during an earthquake causes
loose sediment to act more like a liquid.
32.
Where do volcanic arcs often form?
Where an oceanic plate subducts beneath a continental plate
33. Know the following in order:
1.
As tectonic plates move,
rocks have tension forces
acting on them.
2.
The rocks stretch and bend
3.
The rocks stretch beyond their elastic limit
4.
The rocks snap, releasing energy.
34. Be familiar with the seismogram records on the top of pages 262 and 263. Be
able to identify the arrival time differences of P-waves and S-waves. (Know
which are P-waves and which are S-waves.
35. Know this chart:
Plate Motion
Prominent Fault Type
Transform
Convergent
Divergent
Strike – slip fault
Reverse fault
Normal fault
Earthquake
Characteristics
Moderate, strong, shallow
Strong, deep
Weak and shallow