EarthquakeEarthquakess

How do we measure an How do we measure an Earthquake?Earthquake?

We can measure Earthquakes using We can measure Earthquakes using one of two main scales.one of two main scales.– Richter ScaleRichter Scale– Mercalli ScaleMercalli Scale

Mercalli ScaleMercalli Scale

In 1902 Guiseppe Mercalli devised a In 1902 Guiseppe Mercalli devised a scale for measuring the intensity of scale for measuring the intensity of an earthquake by relating it to the an earthquake by relating it to the amount of damage it caused. amount of damage it caused.

In 1931 seismologists modified his In 1931 seismologists modified his scale to adapt to modern American scale to adapt to modern American building standards. building standards.

I Barely felt

II Felt by a few sensitive people, some suspended objects may swing

III Slightly felt indoors as though a large truck were passing

IV Felt indoors by many people, most suspended objects swing, windows and dishes rattle, standing autos rock

V Felt by almost everyone, sleeping people are awakened, dishes and windows break

VI Felt by everyone, some are frightened and run outside, some chimneys break, some furniture moves, slight damage

VII Considerable damage in poorly built structures, felt by people driving, most are frightened and run outside

VIII Slight damage to well built structures, poorly built structures are heavily damaged, walls, chimneys, monuments fall

IX Underground pipes break, foundations of buildings are damaged and buildings shift off foundations, considerable damage to well built structures

X Few structures survive, most foundations destroyed, water moved out of banks of rivers and lakes, avalanches and rockslides, railroads are bent

XI Few structures remain standing, total panic, large cracks in the ground

XII Total destruction, objects thrown into the air, the land appears to be liquid and is visibly rolling like waves

Finding the EpicenterFinding the Epicenter We can use Mercalli’s modified scale to We can use Mercalli’s modified scale to

find the epicenter of an earthquake. find the epicenter of an earthquake.

Today’s activity is a dramatization based Today’s activity is a dramatization based on an actual earthquake that occurred in on an actual earthquake that occurred in Wattsville, California in 1971. Wattsville, California in 1971.

The next few slides are recordings from a The next few slides are recordings from a local radio station that had callers phone local radio station that had callers phone in observations that they could make from in observations that they could make from their location.their location.

KWAT RadioKWAT Radio

Caller ACaller A

Caller BCaller B

Caller CCaller C

Caller DCaller D

Caller ECaller E

Caller FCaller F

Caller GCaller G

Caller HCaller H

Caller ICaller I

Caller J Caller J

Caller KCaller K

Caller LCaller L

Caller M Caller M

Caller N Caller N

Caller OCaller O

Caller P Caller P

Caller QCaller Q

Caller R Caller R

Caller SCaller S

Caller TCaller T

Caller UCaller U

Caller VCaller V

Final TaskFinal Task Now that you are finished marking down Now that you are finished marking down

the number on the Mercalli scale for each the number on the Mercalli scale for each location you want to begin to connect location you want to begin to connect similar numbers on your map. similar numbers on your map.

Be sure to look over your map carefully Be sure to look over your map carefully and draw lines that contain each number. and draw lines that contain each number.

SEE EXAMPLESEE EXAMPLE

Put a star where you think the epicenter Put a star where you think the epicenter would be located.would be located.