8.2 pgs 222-228 SCAFFOLDED NOTES key
NAME ___________________ DATE __________ PD ___
8.2 Measuring Earthquakes
1. Instruments that record earthquake waves are called ______________
2. ___________ are traces of amplified, electronically recorded ground
motion made by seismographs.
3. Seismic waves that travel along Earth’s outer layer are called _______
_______
4. The image below is of a __________, which was made by a __________.
5. P Waves or Primary Waves:
a. Are push-pull waves that ______ (compress) and ______ (expand) in
the direction that waves travel
b. Can travel through _______, _______, and _______
c. Have the greatest ________ of all earthquake waves
6. S Waves or Secondary Waves aka Shear Waves:
a. Travel along Earth’s outer layer
b. Shake particles at right angles to the direction they travel
c. Travel only through __________
d. _________ velocity than P waves
7. To locate an earthquake you must know:
a. Earthquake ________ –you can find from the _______ in P and S
wave arrival times
b. Earthquake _________ – travel time graphs from _____ or more
seismographs can be used to find the exact location of an earthquake
_____________.
8. Earthquake Zones – ______% of occur in a few zones:
a. Circum-Pacific Belt – around the outer edge of the Pacific Ocean aka
______________
b. Mediterranean-Asian Belt – around the Mediterranean Sea
c. Oceanic Ridge System – A continuous belt extending thousands of
kilometers though the world’s oceans
Scales to Measure Earthquakes
9. Richter Scale –
a. Based on the ____________ of the largest seismic wave
b. Each unit of richter magnitude equates to a increase of 10x shaking
c. A good estimate for _________, ___________ earthquakes
10.
Moment Magnitude
a. Measures the __________ released by earthquakes
b. Looks at the amount of _________ that occurs along the _____ zone
c. Scientists like this one and can measure very ________ earthquakes