Chapter 12, Section 2
Students
know why and
Standards
CHAPTER 3d.
10,
SECTION
2 how earthquakes occur and the
scales used to measure their intensity and magnitude.
Objective 1
Objective 2
Objective 3
Assessment
Review
Describe the instrument used to measure
and record earthquakes.
Summarize the method scientists use to
locate an epicenter.
Describe the scales used to measure the
magnitude and intensity of earthquakes.
Finding an Epicenter Lab, Daily Quiz, Chapter
Test
Daily Bellwork, Science Starters, Standards
Practice
KEY TERMS
Create a flashcard for each of the following terms
(found on p.301 in your text book).
 Seismograph
 Seismogram
 Magnitude
 Intensity
If you finish early, study your flashcards!
RECORDING EARTHQUAKES
SEISMOGRAPH is a device that detects and
records vibrations in the ground.
 A SEISMOGRAPH is composed of 3 sensing
devices:

Vertical Motion
 North-South Motion
 East-West Motion

Seismographs record motion by tracing wave
shaped lines onto paper
 A tracing of Earthquake motion is called a
SEISMOGRAM.
 P waves are always recorded first, then S waves

LOCATING AN EARTHQUAKE
Distance to Epicenter= analyze arrival time of P
and S waves.
 Locate the Epicenter = computers triangulate
information from AT LEAST 3 seismograph
stations.

EARTHQUAKE MEASUREMENT
MAGNITUDE= the measure of the strength of an
earthquake; the amount of ENERGY released.
 Magnitude is determined by measuring the
amount of ground motion.
 Richter scale= most common measure of ground
motion
 Moment Magnitude scale= newer scale, measures
the strength based on the size of the area of the
fault that moves.

INTENSITY

Mercalli Intensity Scale measures how much
damage is caused by an earthquake.
QUICK CHECK!!
1. Name the tool scientists use to measure
and record data from Earthquakes:
___________.
2. Which wave is recorded first? __________
3. How many seismographs are needed to
locate the epicenter? _______________
BRAIN POP EARTHQUAKES
ASSESSMENT
Finding an Epicenter Lab
DAILY QUIZ