Friday, March 23nd

•1 Attendance• 2 Go over

Review Sheet• Test• Pass Back papers

Da’ Lab• When did the P-wave hit?• When did the S-Wave hit?• Subtract to get the difference.• Use the chart to find the epicenter distance

• Mark the edge of the paper with the time difference• Move paper to find the place where the two lines

are that far apart.• Look down to see the epicenter distance

• Use the safety compass to draw the circle - with the correct distance around the city.

EarthquakesThe sudden shaking of the ground.

I. Earthquakes

Are sudden trembling or movement of the ground

There are over 1 Million Per year (1 per second)

A major cause of earthquakes is faulting

Fault

I. Earthquakes

Faulting – sudden movement of rock along planes of weakness in the earth’s crust

Faults - planes of weakness in the Earth’s crust.

Rock is stressed to the breaking point and the two halves have an elastic rebound.

Great masses of rock suddenly scrape past one another.

Focus

Epicenter

I. Earthquakes

Focus - the point where the rock breaks.

Epicenter - the point on the Earth’s surface directly above the focus. Analysis of seismic

waves allows the determination of the location of epicenters.

Seismograph

Seismogram

II. Earthquake Waves

When faulting occurs, vibrations called seismic waves spread out in all directions from the focus.

Seismograph - a device that detects measures, and records the motions of the earth associated with seismic waves.

II. Earthquake Waves

Seismogram - the line that was recorded on paper by a seismograph

Magnitude - the total energy released by an earthquake

Richter Scale

Mer

calli

Sca

le

P-Waves• Primary / Compressional• First to arrive• Fastest• Can travel through Feverything: • solids, liquids and air

S-Waves• Secondary Waves• Shear Waves• Second to arrive• Travels only through • solids

Name Earthquake Vocabulary1. Earthquake – 2. Faulting –3. Fault- 4. Focus –5. Epicenter – 6. Seismic-7. Seismograph -8. Seismogram -9. Magnitude -10. Richter Scale -11. Mercalli Scale -12. P-wave (primary) -13. S-wave (secondary) -

Questions