1. Section 12-2 Review Page 304 (1-5)

2. #1 Describe the instrument that is used to record seismic waves.
A seismograph consists of three sensing devices that record ground motion: one records vertical motion, one records horizontal east-west motion, and the third records horizontal north-south motion.

3. Seismographs through Time

4. #2
Compare a seismograph and a seismogram.
A seismograph is the sensing device. The seismogram is the tracing of earthquake motion made by the seismograph.

5. Seismograph

6. Seismogram

7. #3
Summarize the method that scientists used
to identify the location of an earthquake
before computers became widely used.
Scientists drew circles on a map around three seismograph stations. They used the lag time between the arrival of the P waves and the S waves to determine the distance between each site and the epicenter. The epicenter was located where the three circles intersected.

8. “LAG TIME” Earthquake P-wave and S-wave Travel Time
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
Earthquake wave travel time (minutes)
Distance from epicenter (km)
Earthquake
P-wave and
S-wave Travel
Time
“LAG TIME”

9. Locating the Epicenter

10. #4 Describe the scales that scientists use to
measure the magnitude of an earthquake.
Richter Scale - determines earthquake strength based on ground motion and adjusts for distance.
Moment Magnitude - measures earthquake strength based on the size of the area of the fault that moves, the average distance the fault blocks move, and the rigidity of the rocks in the fault zone.

11. Richter Scale

12. Richter Scale

13. Mercalli Scale – the measure of the intensity of an earthquake
Mercalli Scale – the measure of the intensity of an earthquake. Measure from I to XII (12).
I – is not felt except by very few under especially favorable conditions
XII – causes total destruction; distorts lines of sight; objects are thrown into the air

14. Mercalli Scale

15. #5
Explain the difference between magnitude
and intensity of an earthquake.
Magnitude is the measure of an earthquake’s strength. Intensity a measure of the effects of an earthquake on a particular area.

16. For example . . . Utah Earthquake Magnitude – 2.6 (Richter Scale)
Intensity – Depends on distance from the epicenter.

17. 6. Summarize how energy is transferred between the sun and consumers in an ecosystem.
Sun’s energy is stored in carbohydrates (sugars and starch’s) produced by plants during photosynthesis.
The energy is obtained by consumers that eat the plants.
Energy is transferred to other consumers that eat those consumers.
Energy from animal and plant remains is transferred to decomposers when they die.

18. The End????