Ch. 8 Sct. 1
Jan 18, 2016
Ch. 8 Sct. 1
When rocks strain and potential energy builds up over time.
When the potential energy is released because the rock breaks, vibrations are released through the rocks.
The surface of a break in the earth’s rocks/crust
99% of earthquakes occur at a fault Normal Reverse Strike Slip-Fault
Divergent Dip-Slip Fault
ConvergentThrust Fault
•San Andreas pics.•1906 quake.
Waves released by earthquakes Primary Waves (P) Secondary Waves (S) Surface Waves
P wavesTravel fastest through rock Move like compression waves/sound
waves
S wavesTravel second fastest through rockMove like transverse waves/light
waves
Slowest and largest seismic wavesTravel outward from epicenter in a
variety of forms Ocean waves Backward rolling waves Side to side, swaying motion
Most destructive seismic wave
Focus Deep within the earth’s crust where the
actual rock structure snapsEpicenter
The point on the earth’s surface directly above the focus.
Seismograph Records the magnitude of earthquakes
Based on measurements of seismic wave heights from seismograph readings
Difference between 1.0 and 2.0 10x higher waves on seismograph 32x more energy in earthquake
The strongest recorded earthquake in history. 1960 off the coast of Chile 9.5
The strongest recorded earthquake in North America. 1964 near Anchorage, Alaska 9.2
Measure the intensity/damage of an earthquake.
Specific to the distance away from the epicenter.
Occur when earthquakes happen on the ocean floor.
The energy from the quake is transferred to the water and causes huge waves to form.
Waves don’t gain height until they near the land.
See page 216 of text.