EarthquakesAMSTI

Earthquake• Shaking & vibrating of

earth

• Natural event

• Large sudden release of energy along cracks of Earth's crust

• Beyond human control

• Studied by seismologist

• Monitored by satellites

Myths

• Throughout history, people have had imaginative explanations for why earthquakes happen

• Giant catfish holding Earth

• Giant frog jumping on Earth

• Giant tortoise carrying Earth

Waves

• Travel in all directions from center of circle

• Surface waves (up & down)

• Body waves: P & S waves (push/pull & side/side)

• S waves don't travel through liquids

Speeds of Waves

• Each has a constant speeds; but P wave is faster

• Larger difference between P & S wave arrival means further the seismograph station is from location of EQ

EQ resistant homes

• Foundation connected to rock deep underground

• Walls & beams tied together

• Liquid concrete sprayed on brackets

Seismographs• Instrument that records

EQ- located all over the world

• 3 different locations needed to locate epicenter

• Seismogram- paper the vibrations recorded on

• Each tic = 1 minute if each day

• Pen moves as the vibrations move

Tsunamis

• Huge wave

• Can be caused by EQ

• Can travel thousands of miles

Focus & Epicenter

• Focus- point where EQ begins

• Epicenter- point on surface above focus

Canines to the Rescue

• Dogs have stronger senses- especially for smell-sniff the air

• National Association for Search & Rescue- 1500 handlers

Ring of Fire

• Circum-Pacific Belt

• Consists of a chain of EQ around Pacific Ocean

• Due to deep sea trenches

• Common locations- California, Alaska & Japan

Richter Scale

• Named after Charles Richter

• Measures magnitude of EQ by measuring the "swing" of the wave

• Measures 1-8+

Worldwide Statistics• Less than 3- 9000 per day

• 3-3.9- 49000 annually

• 4-4.9- 6200 annually

• 5-5.9- 800 annually

• 6-6.9- 120 annually

• 7-7.9- 18 annually

• 8+ - 1 annually

Earth's Interior

• Layers: Core, Mantle & Crust

• 2 types of crust: Oceanic & Continental

Sonar

• Sending & receiving an echo

• Used to map the interior of the Earth & the floor of the ocean

Tectonic Plates

• Earth's crust is broken into segments that fit together like a puzzle

• Plates float over the mantle

• Plates move which can cause EQ

Movement of Plates

• Convergent- 2 plates push together- forms mountains

• Divergent- 2 plates pull apart- forms trench or valley-dense oceanic plate sinks under continental plate

• Transform- 2 plates slide past each other- no new land is formed

San Andreas Fault• California

• Rocks have jagged surfaces that hook on each other which wear down after the EQ ruptures

• Rocks that bend are called ductile

• Fences & rivers change shape as result of moving plates

Theory of Pangea

• Belief that all continents were once a single large landmass- super continent

• Proof? Sides look like they fit together like a puzzle, identical fossils separated by oceans, scratches on glaciers & mountain ranges line up on different continents

Test Time Make an A!