EarthquakesEarthquakes

A Whole Lot of shakin’ going A Whole Lot of shakin’ going on!on!

What are Earthquakes and where What are Earthquakes and where do they occur?do they occur?

Seismology is the study of earthquakes.Seismology is the study of earthquakes. Most earthquakes occur near the edges of Most earthquakes occur near the edges of

tectonic plates tectonic plates due to their movement.due to their movement.

FaultsFaults are breaks in the crust along which are breaks in the crust along which blocks of the crust slide relative to one blocks of the crust slide relative to one another. They occur in many places, but another. They occur in many places, but are most common near the edges of are most common near the edges of tectonic plates.tectonic plates.

EarthquakesEarthquakesEarthquakesEarthquakes

Location of worldwide earthquakes

What Causes Earthquakes?What Causes Earthquakes?

As the tectonic plates scrape against As the tectonic plates scrape against each other, stress builds up along each other, stress builds up along faults near the plates’ edges.faults near the plates’ edges.

As a response to the stress, the rock As a response to the stress, the rock in the plates bend or fold.in the plates bend or fold.

Bending or folding, also called Bending or folding, also called deformation is the change in the deformation is the change in the shape of rock in response to stress.shape of rock in response to stress.

What Causes Earthquakes?What Causes Earthquakes?

How Do Earthquakes Travel?How Do Earthquakes Travel? The energy released travels in the form of The energy released travels in the form of

seismic wavesseismic waves.. Seismic waves are waves of energy that Seismic waves are waves of energy that

travel through the Earth.travel through the Earth. Waves that travel through the Earth’s Waves that travel through the Earth’s

interior are called primary waves (P interior are called primary waves (P waves).waves).

Waves that travel along the Earth’s Waves that travel along the Earth’s surface are called surface waves (S surface are called surface waves (S waves).waves).

Surface WavesSurface Waves

Surface waves Surface waves move the ground move the ground up and down in up and down in circles as the wave circles as the wave travel along the travel along the surface.surface.

Surface WavesSurface Waves

Move along the Earth’s surfaceMove along the Earth’s surface Produces motion in the upper crustProduces motion in the upper crust More destructiveMore destructive

How are Earthquakes Measured? How are Earthquakes Measured? Richter ScaleRichter Scale

Typical Typical SeismogramSeismogram

http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

How do scientists calculate how far a location How do scientists calculate how far a location is from the epicenter of an earthquake? is from the epicenter of an earthquake?

Scientists calculate the difference Scientists calculate the difference between arrival times of the P waves between arrival times of the P waves and S wavesand S waves

The further away an earthquake is, the The further away an earthquake is, the greater the time between the arrival of greater the time between the arrival of the P waves and the S wavesthe P waves and the S waves

SeismologistSeismologist

FocusFocus – – point inside the Earth where an point inside the Earth where an earthquake beginsearthquake begins

Epicenter – point on Earth’s surface above Epicenter – point on Earth’s surface above focusfocus

HaitiHaitiJanuary 2010 killed more than 200,000 January 2010 killed more than 200,000

people and left 1.5 million homeless.people and left 1.5 million homeless.

HaitiHaiti

San Andreas FaultSan Andreas Fault

The San Andreas Fault is the sliding The San Andreas Fault is the sliding boundary between the Pacific Plate boundary between the Pacific Plate and the North American Plate. It and the North American Plate. It slices California in twoslices California in two

San Andreas FaultSan Andreas Fault

San Andreas FaultSan Andreas Fault

San AndreasSan Andreas 01/09/1857 -Fort Tejon, 7.9 magnitude01/09/1857 -Fort Tejon, 7.9 magnitude 04/18/1906 - San Francisco, California, with a magnitude 7.8, was 04/18/1906 - San Francisco, California, with a magnitude 7.8, was

one of the worst earthquake in California history. The earthquake one of the worst earthquake in California history. The earthquake killed over 3,000 people and caused $524 million in property loss. killed over 3,000 people and caused $524 million in property loss. The damage in San Francisco alone was over $20 million. Due to The damage in San Francisco alone was over $20 million. Due to broken pipelines, water was shut off to the entire city. Many fires broken pipelines, water was shut off to the entire city. Many fires soon broke out throughout the city and caused major devastation soon broke out throughout the city and caused major devastation as there was no water to put them out. This earthquake caused as there was no water to put them out. This earthquake caused the lengthiest rupture of a fault in U.S. history. People as far as the lengthiest rupture of a fault in U.S. history. People as far as western Nevada and southern Oregon could feel the tremor.western Nevada and southern Oregon could feel the tremor.

On 02/24/1892- Imperial Valley, California with a magnitude of 7.8, On 02/24/1892- Imperial Valley, California with a magnitude of 7.8, the third largest earthquake in California history occurred. This the third largest earthquake in California history occurred. This earthquake did quite a bit of damage, but caused no casualties. It earthquake did quite a bit of damage, but caused no casualties. It destroyed many homes and cause rockslides. About 155 destroyed many homes and cause rockslides. About 155 aftershocks were felt in the 12 hours following this quake.aftershocks were felt in the 12 hours following this quake.

San AndreasSan Andreas

Last big earthquake in California was Last big earthquake in California was in 1999.in 1999.

7.1 magnitude7.1 magnitude In a remote location, so next to no In a remote location, so next to no

damage.damage. California is over due for the next big California is over due for the next big

earthquake.earthquake.

New Madrid FaultNew Madrid Fault

New MadridNew Madrid

New Madrid FaultNew Madrid Fault

http://www.youtube.com/watch?http://www.youtube.com/watch?v=SjqVidNX23ov=SjqVidNX23o

New Madrid New Madrid

http://en.wikipedia.org/wiki/http://en.wikipedia.org/wiki/New_Madrid_Seismic_ZoneNew_Madrid_Seismic_Zone

TsunamisTsunamis

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

Formation of a tsunamiFormation of a tsunami

http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

EarthquakesEarthquakesEarthquakesEarthquakes

Tidal waves or Tsunamis result when the low amplitude long wavelength wavesreach the shallow shoreline and begin to feel the bottom of the sea floor. This Shortens the wavelength and increase the amplitude (height).

JapanJapan

8.9-magnitude 8.9-magnitude March 11, 2011March 11, 201120,000 lives lost20,000 lives lost

JapanJapan

JapanJapan

Ring of FireRing of Fire

90% of all earthquakes occur along 90% of all earthquakes occur along the ring of fire. the ring of fire.

Other quakesOther quakes

http://www.youtube.com/watch?http://www.youtube.com/watch?v=86OXNrqV4-Mv=86OXNrqV4-M