Volcanic

• Earthquakes


  Result of the sudden release of energy stored in the Earth's crust

  
• Hypocenter/ Focus

  The point within the Earth where an earthquake originates

  
• Epicenter


  The point directly above the hypocenter on the Earth's surface
• Richter scale


  Used to measure the intensity of an earthquake

  
• Volcanic eruptions


  Occur when magma, gas, and other volcanic materials are expelled from a volcanic vent or fissure onto the Earth's surface or into the atmosphere
• Magma chamber


  Reservoir where molten rock accumulates
• Volcanic eruption is triggered by 


  1. Influx of new magma

  2. Release of gases

  3. Destabilization of the volcano's structure
• Ejecta


  Magma, gas, and volcanic ash expelled during a volcanic eruption
• Layers of the Earth


  • Crust
  • Mantle
  • Outer core
  • Inner core

  
• Continental crust


  • Characterized by mountain ranges, plateaus, and cratons
  • Thicker, less dense, and older than oceanic crust
  • Rocks found are often the oldest in the world

  
• Felsic rocks


  Rocks rich in silica (SiO₂) and aluminum (Al), such as granite and gneiss

  
• Oceanic crust


  • Mainly composed of basalt, a mafic rock rich in iron (Fe) and magnesium (Mg)
  • Much thinner than continental crust, typically only around 6-10 km thick

  
• Formation of oceanic crust


  Continuously formed at mid-ocean ridges by the upwelling of molten rock from the Earth's mantle

  
• Rock cycle


  • Igneous rock
  • Sedimentary rock
  • Metamorphic rock

  
• Intensity: 


  measures the shaking in a certain location
• Magnitude


  Measures the energy released at the source of the Earthquake
• Volcanic Eruptions


  OCCUR WHEN MAGMA, GAS, AND OTHER VOLCANIC MATERIALS ARE EXPELLED FROM A

  VOLCANIC VENT OR FISSURE ONTO THE EARTH'S SURFACE OR INTO THE ATMOSPHERE
• DURING AN ERUPTION, MAGMA, GAS, AND VOLCANIC ASH ARE EXPELLED FROM THE

  ____________ ONTO THE EARTH'S SURFACE.

  VENT OR FISSURE
• Crust 


  The Earths outermost layer
• Mantle 


  a thick layer of solid rock that extends to

  a depth of about 2,900 kilometers.
• OUTER CORE


  a liquid layer composed primarily of iron

  and nickel
• INNER CORE


  a solid sphere consisting mainly of iron

  and nicke
• Continental Crust


  • Characterized by mountain ranges, plateaus, and cratons.
  • Thicker, less dense, and older than Oceanic Crust.
  • Rocks found on this kind of crust are
  • often the oldest in the world.
• CONTINENTAL CRUST


  Mainly composed of GRANITE, GNEISS, and

  other FELSIC ROCKS, which are rich in silica

  (SiO2) and aluminum (Al).
• Continental Crust


  2.47gm/cm
• Oceanic Crust


  3.0 gm/cm
• CONTINENTAL CRUST


  Mostly shaped by the long-term process of

  mountain formation, which occurs when

  tectonic plates collide, causing rocks to

  melt and then solidify again.
• OCEANIC CRUST


  Mainly composed of basalt, which is a mafic rock rich in iron (Fe) and magnesium (Mg)
• OCEANIC CRUST


  Continuously formed at mid-ocean ridges by the upwelling

  of molten rock from the Earth'

  s mantle.
• OCEANIC CRUST


  Much thinner than continental

  crust, typically only around 6-10

  km thick.
• IGNEOUS ROCK


  Formed by the cooling

  and crystallization of

  molten magma at

  volcanoes and mid-

  ocean ridges.
• METAMORPHIC ROCK


  Are formed when igneous or

  sedimentary rocks are exposed

  to conditions of high heat and

  pressure.
• SEDIMENTARY ROCK


  The deposition and hardening

  of sediments. Both igneous

  and sedimentary rock types

  can transform physically and

  chemically into a third rock

  type.
• ROCK CYCLE

  The rock cycle is the transition of rocks among three different rock types

  over time.
• DENSITY

  Continental crust is less dense, so it floats higher on the semi-

  fluid upper mantle (called the asthenosphere) compared to oceanic crust.
• AGE

  The continental crust is older than the

  oceanic crust.
• LOCATION

  Because continental crust is less dense than oceanic crust

  it floats higher on the mantle, just like a piece of Styrofoam floats

  higher on water than a piece of wood does.
• CONTINENTAL & OCEANIC CRUST

  This fact can be easily explained by the recycling

  process of the oceanic crust. The recycling

  process does not happen to the continental

  layer.
• THICKNESS

  Oceanic crust is much thinner than continental crust. Oceanic

  crust is typically about 5-10 kilometers thick, while continental crust can be

  up to 40 kilometers thick.
• FOSSILS

  Oceanic crust is much younger than

  continental crust, so it does not contain as many

  fossils.