EARTHQUAKES By: Hoil Patrick Pae Daniel Vasquez Julie Freed

Definitions (continued) Magnitude: a measure of the strength of an earthquake Intensity: the amount of damage caused by an earthquake. Tsunami: a giant ocean wave that forms after a volcanic eruption, submarine earthquake, or landslide.

Definitions (continued) Seismograph: instrument that records vibrations in the ground. Seismogram: a tracing of earthquake motions that is recorded by a seismograph. Seismic gap: area along a fault where relatively few earthquakes have occurred recently but where strong earthquakes are known to have occurred in the past.

Definitions (continued) Earthquakes: a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move. Elastic rebound: the sudden return of elastically deformed rocks to its undeformed shape Fault zone: a region of numerous, closely spaced faults.

Equations The richter scale was one way the scientists measured the strength of an earthquake. Magnitude=log 10 (amplitude)+correction factor

Anatomy of an earthquake Focus-Location within earth along a fault at which the first motion of an earthquake occurs Epicenter- Point on earth’s surface directly above an earthquakes foci. 90% of continental earthquakes have shallow focus. Earthquakes with shallow foci cause the most damage.

Body Waves 2 main body waves: P-Waves: Primary waves or compression waves S-Waves: Secondary waves or shear waves

Surface Waves Form from motion along shallow faults Surface wave= Slowest moving waves Mostly cause the greatest damage 2 Types: Rayleigh Waves: Ground moves in elliptical, rolling motion Love Waves: Rock moves side-to-side & perpendicular to direction wave travels.

Seismic Waves and Earth’s Interior 3 Main layers of earth: Crust, Mantle, and Core. 5 Mechanical Layers: Lithosphere, Asthenosphere, Mesosphere, Outer core, and inner core. Shadow zones: an area on earth’s surface where no direct seismic waves from a particular earthquake can be detected

Earthquakes and Plate Tectonics Earthquakes are the result of stress in lithosphere Convergent Oceanic Environments: Plates move toward each other and collide. Divergent Oceanic Environments: Plates move away from each other. Continental Environments: Plates converge, diverge, or move horizontally in opposite directions.

Earthquake Safety Before earthquake- have food, flashlight batteries and portable radio and clothes. During earthquake- stay in hallways and if in a car then stay somewhere safe. After earthquake- stay calm.

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