Download Earthquakes Focus

 Bellringer:
 Answer
Place on BR sheet
Question # 5 on page 260
 Objective:

Determine where
tectonic plates are
located on Earth
 Agenda:
Continental Drift
activity
 Boundary Lab
 Start Earthquake
notes

 The
shaking or trembling caused by the
sudden release of energy
 Usually associated with faulting or
breaking of rocks
 Continuing adjustment of position results
in aftershocks
Earthquakes
• Focus: The point
within Earth where
faulting begins
• Epicenter: The point
directly above the
focus on the surface
• Intensity:
size/strength of
earthquake
Seismograph:
instrument that
measures strength of an
earthquake.
 zigzag reading is a
seismogram
 Three seismographs can
be used to pinpoint the
epicenter of an
earthquake.
(Triangulation)

 Magnitude
=
intensity


Measured by Richter
Scale (1-10)
Each number is 32
times stronger than
previous number.



~80% of all earthquakes occur in the “Ring of Fire”
 most of these result from convergent margin activity
5% occur in the interiors of plates and on spreading ridge
centers
more than 150,000 quakes strong enough to be felt are
recorded each year
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Damage in Oakland, CA, 1989
Building collapse
Fire
Tsunami
Ground failure