22 terms

Earthquakes and Volcanoes

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Earthquake
the release of energy along a fault or plate boundary.
Seismic waves
the energy released during an Earthquake.
P waves
The first wave to arrive during an Earthquake. This wave has the ability to travel through solids and liquids. This wave compresses and expands rock.
S waves
The second wave to arrive during an Earthquake. This wave only travels through solids. Wave motion is in a 90 degree movement to the directions of the wave. Either up and down and back and forth.
Surface waves
The third wave to arrive during an Earthquake. This is the most destructive wave of an earthquake as it moves the slowest and moves objects both back and forth and up and down.
Fault
The crack in the crust where the rock moves.
Focus
The point deep within Earth where the seismic energy from an Earthquake is releases.
Epicenter
The point on the Earth's surface directly above the focus of an earthquake.
Faulting
the movement of rock by an earthquake.
Aftershock
Small earthquakes that follow a major earthquake event.
Foreshock
Small earthquakes that happen before a major earthquake event.
Seismograph
A machine that is used to monitor earthquakes. This machine creates a print out called a seismogram.
magnitude
The intensity of an earthquake.
Liquefaction
When loose sediment becomes saturated with water during an earthquake and landslides take place.
Tsunamis
A large wave triggered by an underwater earthquake.
Name 2 other dangers from earthquakes
landslides and fire
Viscosity
a liquids resistance to flow
Shield volcano
a broad gentle sloping volcano created by thin or low viscosity magma or lava. Ex: Hawaiian Islands
Cinder cone Volcano
a violently erupting volcano with high silica or high viscosity magma. This type of volcano will erupt once and use up all it power and rarely erupts again. Smaller mountain. Ex: SP Crater near Flagstaff, AZ
Composite or stratocone volcano
an alternating violent erupting and quiet erupting volcano and has the potential to create low and high viscosity or low and high silica magma or lava. This volcano will build in layers of lava and pyroclastic material. Ex: Mount St. Helens
Pyroclastic Material
The volcanic material that is created by high viscosity magma and includes, high silica lava, ash, cinders, and lava bombs.
Silica
a compound made of silicon and oxygen.