Presentation on theme: "Chapter 12: Earthquakes. Where do earthquakes tend to occur? Earthquakes can occur anywhere, but they tend to occur on and near tectonic plate boundaries."— Presentation transcript:
Seismograph: The instrument Apparatus to measure and record vibrations Seismogram: The actual wiggle Record of an earthquake recorded by a seismograph The difference between a “Seismograph” and a “Seismogram” FuturePast
Earthquakes do the same thing, but in 3 dimensions
Seismic Waves Body Waves: in geology, a seismic wave that travels through the body of a medium. Surface Wave: in geology, a seismic wave that travels along the surface of a medium and that has a stronger effect near the surface of the medium that it has in the interior.
P-waves primary wave compression wave fastest of the seismic waves can travel through solids, liquids, and gases Surface waves 2 types: Love waves and Rayleigh waves Slowest seismic waves May cause the greatest damage in an earthquake S-waves secondary wave shear wave second-fastest seismic wave can only travel through solids Seismic waves
Surface Waves Love Waves: cause rock to move side to side and perpendicular to the direction in which the waves are traveling. Rayleigh Waves: cause the ground to move with an elliptical, rolling motion.
Travel time from San Diego to Los Angeles 25 seconds P-waves 25 seconds 41 seconds S-waves 41 seconds 50 seconds Surface waves 50 seconds
Types of Seismic Waves: P-wave, S-wave, surface wave
Seismic Waves and Earth’s Interior Shadow Zone: an area on Earth’s surface where no direct seismic waves from a particular earthquake can be detected. Shadow zones exist because the materials that make up Earth’s interior are not uniform in rigidity.
Seismic data can also be used to learn about Earth