Download measure earthquakes

Do Now
-Clear your desk of all but your ISN and
textbook.
-Title p. 107 of your ISN, Monitoring
Earthquakes and then add it to your TOC
-On p. 106 of your ISN, answer this question:
How do you think we measure earthquakes?
AGENDA
• Do now
• PowerPoint and notes
• Video
• Wrap up
• Journey to the Center of the Earth
How big was that earthquake?
• There are 3 commonly used scales
that exist to measure earthquakes
1. Mercalli Scale
– Rates earthquakes according to their
damage at a given place.
– Same earthquake can have different
ratings depending on the location.
See p. 55 of your textbook.
2. The Richter Scale
• Determines the magnitude
by measuring seismic
waves and fault movement.
• Measured by seismograph.
• Accurate measurements for small nearby
earthquakes, inaccurate for large and distant
earthquakes.
While watching this video…
• Be ready to answer this question:
–Explain how scientists measure an
earthquake’s seismic waves.
Seismographs
• Seismic waves cause base or drum to vibrate.
• The weight is suspended with a pen attached
to it. It moves slightly.
3. The Moment Magnitude Scale
• Estimates the total
energy released by
an earthquake.
• Can be used near or
far away
• Studies data from
seismographs to
show strength of
seismic waves.
*The earthquake in Haiti (2010) had a moment magnitude of 7.
*Typically, a moment magnitude of 8 is needed to create a large tsunami.
Instruments That Monitor Faults
(look at textbook p. 63 for great visuals)
• Tiltmeter- measures the tilting or raising
of land
• Creep Meter- measures horizontal
movement of ground
• Laser-Ranging Devices- detects
horizontal fault movement with a laser
• GPS Satellites- measures elevation and
horizontal movement of faults
Wrap Up!
Which device could a scientist
NOT use to measure the
movement of the the San Andreas
Fault?
Exit Ticket
A seismograph records the strength of an
earthquake’s seismic waves. Think about what we
learned earlier this week. What does this seismogram
reinforce about S, P and surface waves?
Stations
1.Work on your station packets.
2.Continue working on your
Journey to the Center of the
Earth.