Social Studies 2

• There is energy inside the earth. Some ways you can see it is in:

  • volcanoes
  • earthquakes
  • geysers and hot springs
  • continental drift
  • mountain formation
• The earth is divided in layers

  • Crust
  • Mantle
  • Outer core
  • Inner core
• The lithosphere works like the earth’s shell
• The lithosphere is divided into seven tectonic plates
• The South American plate is responsible for most of the earthquakes in Mexico
• Lithosphere movements cause geographical phenomena
• Continents are made of sedimentary rocks
• Continents are made up of seven major plates
• Convergent = Collides against each other
• Divergent = Moves apart from each other
• Transform = Slides against each other
• Plate movement is caused by the convection currents in the mantle.
• Interactions between plates cause almost all of the different landforms
• Convergent boundaries

  • Continental-oceanic plate collision: One plate sinks under the other one. It usually is the oceanic plate. It creates oceanic trenches
  • Continental-continental plate collision: None of the plates sink under the other, they collide. This causes mountains and earthquakes.

  Divergent boundaries

  Space left by this type of boundary is filled with molten rock. The separation is called rift. It can create valleys.

  Transform boundaries

  Plates pass each other horizontally, creating a fault
• Valdivia, Chile (9.5)

  22 May 1960

  Prince William Sound, Alaska (9.2)

  28 March 1964

  Sumatra, Indonesia (9.1)

  26 December 2004

  Sendai, Japan (9.0)

  11 March 2001

  Kamchatka, Russia (9.0)

  4 November 1952
• Parts of a volcano

  • Eruption column: Expelled gases
  • Crater: Surrounds the volcanic vent
  • Volcanic cone: Landform made of layers
  • Magma chamber: Build up of molten rock beneath the surface
• Materials produced by a volcanic eruption

  Gases: Mostly carbon dioxide and water vapor

  Molten rock: Also called lava. Lava is more fluid as temperature increases. Less fluid lava is viscous. Viscous lava is more dangerous.

  Solids: Fluids are ejected into the air and turn into solids. Three types:

  • Lapilis
  • Ashes
  • Volcanic bombs
• Vulcanian


  • Columns of gases and ash can go up from 4 to 10 km
  • Eruptions have a high level of explosivity
  • Can create a collapse with flowing clouds
• Pilinian

  • Columns of pyroclastic materials and gases can go up to 20 km
  • Eruptions have a very high level of explosivity
  • Can produce a collapse caldera
• Types of eruptions

  • Pilinian
  • Vulcanian
  • Strombolian
  • Hawaiian
• Strombolian


  • Viscous lava and large amounts of pyroclastic materials are ejected
  • Medium level of explosivity
  • Can cause pyroclastic falls
• Hawaiian


  • Lava with low viscosity
  • Volcanic bombs, lapillis, and ashes are ejected
  • Low level of explosivity
  • Can cause lava flow which can destroy cities
• Key words

  • released
  • underground
  • waves
  • primary
  • secundary
  • damage
• Earthquakes hazards (ranked)

  1. Falling buildings
  2. Tsunami probabiliity
  3. Landslides
• Volcanic Eruptions hazards (ranked)

  1. Toxic ash
  2. Lava can damage infratsructure
  3. Gravitational collapse