1. Chapter 12 - Section 2 Measuring Earthquakes

2. WHAT WE KNOW…
____________________ are the shaking of Earth’s crust caused by _____________________________as lithospheric plates shift
Focus: the point _______________where seismic activity begins
Epicenter: the point _____________________directly above the focus.

3. LOCATING AN EPICENTER Use triangulation:
Data from 3 different seismograph stations
Look at ___________________________(time difference) between the arrival of ____ waves and ____ waves
The ___________the lag time between P & S waves the ____________ you are from the earthquake’s ______________.

4. MAGNITUDE ___________ or amount of _____________released
It is a measure of the amount of ___________________
Measured using the _________________________

5. Richter Scale
Measures the ______________________ of an earthquake on a ___________________
Richter magnitude is determined by measuring the largest amplitude (wave height) recorded on the seismogram.

6. RICHTER SCALE
Each increase in _____ on the Richter Scale represents a _____ fold increase in the wave magnitude.

7. INTENSITY
A measure of the __________________ of an earthquake, uses the ______________________
Dependent on:
1. magnitude of earthquake
2. distance from epicenter
3. type of rock underlying region
4. ____________________________________________
Varies for each event

8. MERCALLI SCALE Mercalli Scale Description of what happened
___________________________
XII total destruction
Not a true indication of the actual
strength of an earthquake

9. MERCALLI SCALE

10. Magnitude vs. Intensity
Would be possible for an earthquake in two locations to have the same MAGNITUDE on the Richter Scale but a different INTENSITY on the Mercalli Scale?
Why or why not?

11. Richter and Mercalli Scales