Bellringer Vocab Quiz TODAY!!!! Test Wednesday Direction Type of Stress Plate Boundary Type of Fault Pulling apart Pushing together Horizontally sliding

Earthquake Effects

Origin of an Earthquake Focus – the location (usually several km below Earth’s surface) where an earthquake originates Epicenter – the location on Earth’s surface that is directly above the focus The closer the focus is to Earth’s surface, the worse the effects of the earthquake

Seismic Waves Seismic Waves – ground vibrations during an earthquake Begin at the focus and spread out from there

Seismic Waves Three types of seismic waves: Primary Waves (P-Waves) Secondary Waves (S-Waves) Surface Waves (L-Waves)

Primary Waves (P-waves) Fastest-moving seismic waves Rocks are squeezed and pulled in the same direction as the waves travel

Primary Waves (P-waves) P-waves can travel through Earth’s surface, mantle, and inner and outer cores P-Wave – travels through the mantle and core

Primary Waves (P-waves)

Secondary Waves (S-waves) Second-fastest seismic waves (travel slower than p-waves) Rocks moves perpendicular (right angles from) the direction the waves travel

Secondary Waves (S-waves) S-waves can travel through Earth’s surface and mantle, but CANNOT pass through the liquid outer core S-Wave – travels through the mantle, but can’t travel through the core

P-Wave – wave moving to the right, rocks moving to the right Wave Direction P-Wave – wave moving to the right, rocks moving to the right S-Wave – wave moving to the right, rocks moving at right angles (up and down)

Surface Waves (L-Waves) Slowest seismic waves Rocks move in two directions (both vertically and horizontally) Only travel along Earth’s surface (crust) Most destructive of all seismic waves

Locating an Epicenter An earthquake occurs, but where did it originate? There are recording stations all over the world measuring seismic activity

Locating an Epicenter Seismometer – instrument used to measure seismic waves

Locating an Epicenter Seismogram – the printout from a seismometer Which waves (P, S, or L) would show up first on a seismogram? ___-waves, because they’re the ________ P fastest

Locating an Epicenter A seismogram detects P-waves, followed by S-waves The time between them indicates the distance between the recording station and the epicenter The longer the time, the farther away the epicenter

Locating an Epicenter Blue lines = primary waves Red lines = secondary waves

Locating an Epicenter You’re in the middle of a thunderstorm. 1) The lightning flashes, and you immediately hear thunder. 2) The lightning flashes, you count 1,2,3,4,5 and then you hear the thunder. Which storm is closer to you? How can you tell?

100m race 800m race What is the shorter race? Which race has closer results? 800m race

Locating an Epicenter Scientists know how far away the epicenter is, but they don’t know its exact location They draw a circle around the recording station

Locating an Epicenter They gather information from three recording stations and see where the three circles intersect (that’s where the epicenter is located) This is called triangulation

Magnitude More than one million earthquakes happen each year However, 90% of them are not felt/cause little damage Magnitude – amount of energy released during an earthquake

Magnitude Richter Scale – measures the size of the seismic waves and the energy released Ranges from 1-10 (minor to catastrophic) Ex: Haiti 2010 – 7.0 Ex: Japan 2011 – 9.0 http://www.iknowthat.com/mhscience/Earthquakes/earthquake_movie.html

Mercalli Simulator http://www.elearning.niu.edu/about/portfolio/simulations/HomelandSecurity/Mercalli/Mercalli_Scale.swf

Magnitude The higher the magnitude, the greater the damage Some of the most common hazards during an earthquake are structural damage and tsunamis

Tsunami Reenactment https://www.youtube.com/watch?v=mZtYDbTbyB4 Liquefaction https://www.youtube.com/watch?v=TzlodnjPAuc

Earthquake Hazards Tsunamis can cause complete destruction of coastal areas Tsunamis can travel the entire distance of an ocean in only a few hours

Locating an Epicenter Lab Working individually Example problem (follow along) Hints: Y-Axis: each square = 20 seconds X-Axis: each square = 200 km

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