EARTHQUAKES By: Hoil Patrick Pae Daniel Vasquez Julie Freed
Dec 25, 2015
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=log10(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.
Resources
• http://www.google.com/imghp?hl=en&tab=wi
• http://www.ajdesigner.com/phpseismograph/earthquake_seismometer_richter_scale_magnitude.php
• Textbook