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Susan Barton

Earthquakes. And. Volcanoes. Susan Barton. Shaking and trembling of the earth’s crust. The waves travel in all directions More than 1,000,000 occur a year or one every 30 seconds Faulting is the most common cause Earthquakes continue until all the energy is used up

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Susan Barton

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  1. Earthquakes And Volcanoes Susan Barton

  2. Shaking and trembling of the earth’s crust. The waves travel in all directions More than 1,000,000 occur a year or one every 30 seconds Faulting is the most common cause Earthquakes continue until all the energy is used up TSUNAMIS- earthquake on the ocean floor: causing waves to become greater than 20 meters high Defining Earthquakes

  3. Seismic Waves • FOCUS- underground point of origin • EPICENTER- aboveground of origin; most violent shaking occurs at the epicenter • The three main types of seismic waves are: P waves, S waves, and L waves

  4. P Waves • Primary waves • Arrive first at the epicenter • Can travel through solids, liquids, and gases • They are push-pull waves

  5. S Waves • Secondary waves • Can travel through solids, but NOT through liquids and gases • Move in up-down motion

  6. L Waves • Surface waves • Slowest moving seismic waves • Travel on top of Earth’s surface • Cause most of damage to Earth, because they bend and twist the surface

  7. John Milne- 1893 • Seismograph-measures and detects seismic waves • Seismogram- Paper record of waves • Seismologist- scientist who study earthquakes • Richter Scale- a scale that allows scientists to determine earthquake strength based on many readings • 1-10 levels at which an earthquake is measured on amount of damage caused; Above a 6 is very destructive

  8. VOLCANOES • Volcano- place on Earth’s surface that allows magma and other material to erupt • Magma- found beneath the Earth’s surface, it is liquid rock • Lava- magma that reaches the Earth’s surface

  9. Volcanic Dust- less that 0.25 mm in diameter (flour) Volcanic Ash- more than 0.25 less than 5 mm (rice) Volcanic Bombs- few cm to several meters. Cinders- volcanic bombs the size of golf balls Volcanic Fragments

  10. Types of Volcanoes • Cinder Cones- made of mostly of cinders; formed from explosive eruptions • Shield- Made of quiet lava flows • Composite- made up of alternating layers of rock particles; explosive eruptions, then quite lava flows

  11. Crater- funnel shaped pit, or depression at top of volcano Caldera- when a crater becomes too large, it collapses: also can form when the top of a volcano collapses or explodes Dormant- sleeping volcano Extinct- not known to have erupted in modern history Active- Erupts fairly regularly Volcanic Terminology

  12. Ring of Fire

  13. Zones • There are 3 zones: • Ring of Fire- Extends nearly all the way around the edge of the Pacific Ocean • Mediterranean Sea- Italy, Greece, Turkey • Iceland and Atlantic Ocean- Mid Atlantic Ridge

  14. EXTRA! EXTRA! • Mount St. Helens is a volcano is Washington State • San Andreas Fault in California • New Madrid Fault is where we live

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