1. Earthqu akes Earthquake Footage

2. Epicenter The point on Earth’s surface directly above where the energy is released in an earthquake. Focus = point where energy is released Energy that reaches the surface is greatest at the epicenter.

3. Seismic Waves: Energy spreads outward in all directions as vibrations. Seismograph: Instrument that measures and records seismic waves. Seismogram: Seismic record, looks like jagged lines on paper.

4. Triangulation Identifies the epicenter of an earthquake. How? – Get records from 3 seismograph stations. – Plot circles on map from the records. – Find point where all 3 circles intersect. – That's the epicenter. How to find the epicenter using triangulation

5. Measuring time btwn arrival of P & S waves determines the distance btwn the seismograph & the epicenter.

6. Earthquake Waves There are 3 types…  Primary (P) Waves  Secondary (S) Waves  Surface Waves P and S waves explained

7. Primary (P) Waves Move out from EQ focus Travel fastest of the 3 waves Move thru solid and liquid layers of Earth PUSH and PULL rock, creating a back-and-forth motion in the direction the wave is moving Longitudinal wave

8. Secondary (S) Waves Move out from EQ focus Move slower than P waves Only move thru solid rock Move at right angles to P waves, causing rocks to move UP and DOWN and SIDE to SIDE Transverse wave

9. Surface Waves Form when P and S waves reach the surface. Can cause ground to shake, making rock sway from SIDE to SIDE and ROLL like an ocean wave.

10. BRAINPOP Earthquakes