Tectonic Plates

• What are the two types of tectonic plates?

  Oceanic plates and continental plates
• What is an example of an oceanic plate?

  The Pacific Plate
• What is an example of a continental plate?

  The North American Plate
• What is the process called that describes the movement of tectonic plates over time?

  Continental drift
• What was the widely accepted theory for plate movement before slab pull?

  The theory of convection currents in the mantle
• What is slab pull in the context of tectonic plate movement?

  It is when a cold, dense oceanic plate sinks into the mantle and drags the entire plate with it
• What happens at spreading centers under the sea?

  Newly-created crust is hot and light, causing ridge push and plates to move apart
• What are the three types of plate boundaries?

  Destructive, constructive, and conservative boundaries
• What occurs at a destructive boundary?

  Two plates push together, and one is destroyed or subducts
• What hazards are created at destructive boundaries?

  Volcanoes and earthquakes due to friction and melting rock
• What is an example of a destructive boundary?

  The Philippine oceanic plate and Eurasian continental plate
• What happens at a collision zone?

  Two plates of the same density collide and push up against each other
• What landform is created by a collision zone?

  Fold mountains, such as the Himalayas
• What is an example of a collision zone?

  The Himalayas
• What occurs at a constructive boundary?

  Plates are separating by moving away from each other
• What hazards are created at constructive boundaries?

  Volcanic eruptions as magma rises to the surface
• What is an example of a constructive boundary?

  The Mid-Atlantic Ridge
• What occurs at a conservative boundary?

  Plates slide past each other slowly, causing friction
• What hazards are created at conservative boundaries?

  Violent earthquakes due to built-up stress
• What is an example of a conservative boundary?

  The San Andreas Fault
• What is an earthquake?

  A violent shaking of the Earth's crust
• Why are earthquakes difficult to predict?

  They do not exhibit as many signs or symptoms as volcanoes
• What is the focus of an earthquake?

  The point where the ground snaps and moves
• What is the epicenter of an earthquake?

  The point on the surface directly above the focus
• How does the depth of the focus affect earthquake damage?

  A shallow focus causes more surface damage than a deep focus
• What factors control how strongly an earthquake is felt at the epicenter?

  The depth of the focus and the intensity of the snapping
• How does geology affect earthquake effects?

  Softer rocks shake more easily and become fluid, while stronger rocks withstand more stress
• What is liquefaction in the context of earthquakes?

  Rocks shaking violently can turn to a liquid state
• What are tsunamis and how are they created?

  Large sea waves created by undersea earthquakes and landslides
• What is a primary effect of an earthquake?

  Buildings collapsing due to shaking
• What is a secondary effect of an earthquake?

  People injured by falling debris
• What factors determine the damage caused by an earthquake?

  Distance from epicenter, geology, building design, and economic development
• What are short-term impacts of an earthquake?

  Impacts that the area and people can recover from relatively quickly
• What are long-term impacts of an earthquake?

  Impacts that are more long-lasting, such as homelessness
• What does the Richter scale measure?

  The power of the shaking itself
• How is the Richter scale described?

  It is a logarithmic scale, meaning each whole number increase represents a tenfold increase in power
• What does the Mercalli scale measure?

  The intensity of the impacts of the earthquake based on human perception
• How can an earthquake have different magnitudes on the Mercalli scale?

  It depends on how far away from the epicenter the measurements are made
• What does the Richter scale measure?

  The power of the shaking of an earthquake
• Why is the Richter scale called a magnitude scale?

  Because it shows how violently the ground shook