Volcanoes, Earthquakes, and Mountain Ranges

• An Earthquake is a sudden movement of the Earth's Lithosphere.
• Earthquakes are caused by the release of built-up stress within rocks along geologic faults or by the movement of magma in volcanic areas.
• Earthquakes are followed by what?

  Aftershocks.
• What is the point inside the earth where the earthquake started?

  Focus
• The Hanging Wall is the rock above the fault plane. Whilst, the Footwall is the rock below the fault zone.
• What is the point on the surface of the earth directly above the focus?

  Epicenter
• Fault Scarp is a surface expression of a fault that has shifted the ground surface.
• Escarpment is the other term for Fault Scarp
• What is a fracture or zone of fractures between two blocks of rock?

  Fault Line
• Seismic Waves are caused by the sudden movement of materials within the Earth, such as slip along a fault during an earthquake.
• Seismic Waves are divided into two types:

  1. Body Waves - travels through the interior of the Earth
  2. Surface Waves - travels on the surface of the Earth
• Body Waves are divided into two sections:

  1. Primary Waves - the first wave to arrive at a recording station; travel in a back and forth motion.
  2. Secondary waves - the second wave to follow the initial wave; travel in an up and down motion.
• Surface Waves are divided into two sections:

  1. Love Waves - faster to arrive than Rayleigh waves; travel in an up and down motion or side by side
  2. Rayleigh Waves - slower than the previous wave; rolls along the ground with a more complex motion.
• Magnitude is the size of an earthquake described through the use of two different scaling methods such as:

  • Richter Scale - Charles F. Richter; formulated the scale using mathematical equations.
  • Mercalli Scale - Giuseppe Mercalli; formulated the scale using people's observation to estimate the intensity.
• There are four types of Earthquakes which are:

  1. Tectonic Earthquake
  2. Volcanic Earthquake
  3. Collapse Earthquake
  4. Explosion Earthquake
• What is the most common type of earthquake which happens when the shifting of Earth's plates is driven by the sudden release of energy within the limited region of the rocks of Earth?

  Tectonic Earthquake
• Volcanic Earthquake is a phenomenon that often occurs in volcanic regions and can serve as an early warning of volcanic eruptions.
• What are small earthquakes located underground and in mines that are caused by the disintegration of the roof of the mine or cavern or by massive land sliding?

  Collapse Earthquake
• Explosion Earthquake is an earthquake that results from the detonation of chemicals or nuclear devices.
• Theory of Plate Tectonics: the entire lithosphere of the Earth is broken into numerous segments called plates that constantly move. Plate movements cause geologic processes to occur.
• A volcano is an opening in the earth's crust through which lava, volcanic ash, and gases escape.
• The formation of volcanoes are results of what?

  Plate Interactions
• Major Parts of a Volcano:

  1. Magma Chamber - are subterranean reservoirs containing molten silicate fluid.
  2. Conduit - the channel or pipe that carries magma from a reservoir or chamber to the vent.
  3. Vent - Opening at the top of a volcano where magma comes out.
  4. Crater - the area at the top of a volcano that surrounds the vent; normally looks like a large dent.
• The two types of volcanoes (According to history of eruptions) are:

  1. Active Volcanoes
  2. These types of volcanoes have a recent history of eruptions within 10,000 years; they are likely to erupt again.
  3. Extinct Volcanoes
  4. A volcano that has not erupted in over 10,000 years and is unlikely to erupt again.
• Types of Volcanoes according to shape:

  1. Cinder Cone
  2. are named after the igenous rocks called "Cinders" that fall and form the cones after an eruption. They are the most common type of volcano on the planet.
  3. Composite Volcanoes
  4. They are larger and more violent than cinder cones but are not as common around the world.
  5. Lava Dome
  6. The lava in their eruptions is very thick and oozes out of the vent, rather than erupting into the air.
  7. Shield Volcanoes
  8. They are wider rather than tall, and are called by their names because they look like the shield of a medieval knight.
• What is when two plates collide and converge at a convergent boundary, the crust within the plates folds and compresses to cause uplift of Earth's surface?

  Mountain
• The Pacific Ring of Fire is also called the Cirum-Pacific Belt
• The Pacific Ring of Fire is characterized by active volcanoes and frequent earthquakes.
• The Pacific Ring of Fire is approximately 40,000 kilometers.