1. Scripps Institution of Oceanography
Cyber TEAM Academy 2008
Earth Science
Dr. Debi Kilb
Scripps Institution of Oceanography

2. What’s the difference between a “Seismograph” and a “Seismogram”?
Seismograph: The instrument
(Apparatus to measure and record vibrations)
Seismogram: The actual wiggle
(Record of an Earth tremor recorded by a seismograph)

3. Seismic Waves
fault ‘snaps’
energy ripples

4. 3 Main Earthquake Waves
P waves (compressional) 6-8 km/s. Particle motion is parallel to direction of propagation; also called primary waves.
S waves (shear) 3-5 km/s. Particle motion is perpendicular to direction of propagation; also called secondary waves. Do not pass through liquids.
Surface waves (surface) < 3-4 km/s. Waves that travel around the Earth at the surface.
Seismograph

5. Types of Seismic Waves
Seismograph

7. Ground
Motions P
Waves S
Surface Waves

8. epicenter of an earthquake