Download Earthquakes Earthquake: the shaking and trembling that result from

Earthquakes
1.
2.
3.
4.
5.
Earthquake: the shaking and trembling that result from the movement of rock beneath
Earth’s surface.
Seismic waves carry the energy of the earthquake away from the focus, through Earth’s
interior and across the surface. There are 3 categories of seismic waves; p-waves, s-waves,
and surface waves.
The 1st to arrive are the primary waves, or p-waves. P-waves are earthquake waves that
compress and expand the ground like an accordion. S-waves or secondary waves are
earthquake waves that vibrate from side to side as well as up and down. Surface waves move
more slowly than p-waves and s-waves, but they can produce severe ground movements.
Some surface waves make the ground roll like ocean waves.
Focus; the point beneath the Earth’s surface where rock that is under stress breaks, triggering
an earthquake
Epicenter: the point directly above the focus on the surface
Fault: is a break in the crust where slabs of crust slip past each other.
Hazards of earthquakes; shaking of the earth, power lines fall, gas line burst, fires, and
building falling.
To determine where an earthquake occurred you need to find the difference in the arrival of
p-waves and s-waves from 3 different stations. Use the chart to determine the distance
around the station center. Draw a circle around the station center. Where the 3 circles meet
is where the earthquake occurred.
Volcanoes
1. Shield Volcano; thin layers of lava pours out of a vent and hardens on top of a previous
layer. The lava flows gradually build a wide, gently sloping mountain. Form from a hot
spot. Quiet eruptions.
Cinder Cone: when cinders erupt explosively from a volcanic vent, they pile up around the
vent, forming a cone shaped hill.
Composite: lava flow alternates with layers of ash, cinders, and bombs, which has both
quiet and explosive eruptions. Tall cone shaped mountain.
2. Shield- quiet
Cinder cone-explosive
Composite- quiet and explosive
3. Most volcanoes occur along diverging plate boundaries, such as mid-ocean ridge or in
subduction zones around the edge of oceans. Some volcanoes can form at hot spots.
4. High in silica: very thick, light colored, lower in temperature, cause explosive eruption
Low in silica: thin, dark colored, hotter in temperature, cause quiet eruptions
5. Hot spring form when a body of water is heated up from magma. It makes it way to the
surface through a crack in the rock.
6. Hazards of volcanoes lava, pyroclastic flow, fire, gases