Geologic Hazards

• Pangaea is the name for the massive land where all the continents were once together
• Pangaea began to break up around 200 million years ago
• Plate tectonics theory characteristics:

  • Plates are the earth’s outer layer (lithosphere) broken up into several large slabs
  • Plates hold continents and oceans
  • Plates are always moving around the planet
• The two types of crust carried by plates are:

  • Oceanic Crust
  • Continental Crust (thicker)
• On the British Columbia west coast, the 3 plates that interact are:

  • Pacific Plate
  • Juan de Fuca Plate
  • North American Plate
• Convergent Boundaries:

  • When two plates collide
• Divergent Boundaries:

  • When two plates move away from each other
• Transform Boundaries:

  • When two plates slide past each other
• At a subduction zone with interacting plates:

  • Oceanic plate collides with a continental plate at some convergent boundaries
  • Oceanic crust, denser and thinner than continental crust, gets bent and pulled under (subducted) beneath the thicker continental crust, forming a subduction zone
• Trench:

  • A steep-sided depression in the ocean floor
• Volcanoes at subduction zones are formed when:

  • One plate subducts into the earth’s mantle
  • Magma starts boiling and erupts through the crack
• Mountain ranges like the Canadian Rockies are formed when:

  • Two plates converge
  • Neither plate goes under the other, instead, both crumble until rocks are forced up to form a mountain range
• Sea-floor spreading and mid-ocean ridge:

  • When oceanic plates spread apart, molten rock rises to the seafloor causing “mountain ranges” to rise from the ocean floor
• Rift:

  • Found at the bottom of the ocean
  • Regions where 2 plates diverge
• Transform Boundary:

  • When 2 plates slide past each other
  • No creation or destruction, but the shaking causes earthquakes
• A plate is Earth's crust that is broken into different segments
• Plates carry continents and oceans
• Plates are found on the Earth's crust
• Convection currents are heat cycles found in the mantle
• Divergent boundaries are tectonic plates that move away from each other
• Volcanoes are located at divergent boundaries because as the plates move away from each other, magma fills the gap, leading to volcanic reactions
• Convergent boundaries create mountains when two tectonic plates move towards each other and collide
• The "power of water" on the planet causes erosion over time
• CRUST:

  • Thinnest Layer
  • Broken into plates
  • Carries continents and Ocean Floor
• MANTLE:

  • Flows very slow in circles from extreme heat
• CORE:

  • Liquid metal outside
  • Solid metal inside
  • Source of heat that causes mantle to flow
• The 3 different plate boundaries on Canada's BC Coast

  Convergent

  -North American

  -Juan de Fuca

  Divergent

  -Juan de Fuca

  -Pacific

  Transform

  -North American

  -Pacific
• What is the famous mountain range between the Indian and Eurasian Plate?

  Himalayas
• What are the closest transform boundaries to Canada?

  -Queen Charlotte fault

  -San Andreas fault
• How do convection currents in the mantle work?

  The inner core lets out heat which makes magma flow in slow circles in the earth's mantle, moving continents
• What tectonic plate carries Canada (and the US/Central America) and the NW Atlantic Ocean?

  North American Plate
• Between continental and oceanic crust, which one is thicker?

  Continental Crust
• What 3 plates interact on the British Columbia West Coast?

  -Pacific Plate

  -North American Plate

  -Juan de Fuca Plate
• What are convergent boundaries?

  Two plates that move towards each other.
• What are divergent boundaries?

  Two plates that are moving away from each other.
• What are transform boundaries?

  Two plates that slide past each other.
• What is the famous mountain range between the Indian and Eurasian plate?

  Himalayas
• Why are volcanoes located in rift zones?

  They form when magma rises into the gap between diverging plates.
• What are failed rifts?

  They are continental rifting that failed to fully transform into rifts.
• When did Ancient failed rifts start forming?

  They began forming 200 million years ago when Pangea began breaking apart