Earth Science

• Earth


  The third planet from the Sun, where we live, the only planet in the solar system that can support life
• Earth's atmosphere


  • Layer near the surface where clouds are formed
• Layers of Earth


  • Crust
  • Mantle
  • Core
• Crust


  The outermost layer of Earth, where we and other organisms live
• Crust


  • Oceanic crust (6 km thick, made of basalt)
  • Continental crust (30-45 km thick, made of graphite, andesite, basalt)
• Geological processes on Earth's crust

  1. Weathering

  2. Erosion

  3. Plate tectonics
• Weathering


  The breaking down of rocks and minerals on the surface of Earth by agents like water, ice, plants, animals, and temperature changes
• Erosion


  The process of wearing away and transporting soil, rock, and other surface materials by natural forces like wind and water
• Plate tectonics


  The scientific theory that Earth's crust is divided into several plates that move or slide over the mantle
• Asthenosphere

  The ductile part of Earth below the lithosphere, 100-700 km deep, that allows tectonic plates to move
• Mohorovičić discontinuity (Moho)

  The boundary between the lower crust and upper mantle, approximately 700 km thick
• Mantle

  The layer underneath the crust, comprising 84% of Earth's volume, composed of peridotite
• Guttenberg discontinuity

  The boundary between the lower mantle and outer core
• Core

  The central part of Earth, with an outer core (liquid) and inner core (solid), rich in sulfur and iron
• Outer core

  The only liquid layer of Earth, believed to be responsible for Earth's magnetic field, 2,550 km from surface, 4,500-5,500°C
• Inner core

  The solid innermost layer of Earth, approximately 1,220 km in diameter, slightly smaller than the Moon
• Lehmann discontinuity

  The boundary between the outer core and inner core
• The depth of the inner core from Earth's surface makes it inaccessible for analysis and studying, so seismic waves from earthquakes are the primary sources of data to study the core
• Metamorphic rocks are rocks that have undergone a change in texture and composition due to high heat and pressure.
• Sedimentary rocks are created from the accumulation and lithification of sediments.
• Igneous rocks are formed from the solidification of molten rock material.
• The sun is the source of all energy on earth
• In 1990, the Moro and South Cotabato were hit by earthquakes with magnitude that destroyed many properties and establishments
• One of the heritage structures in Bohol that has been damaged by the earthquake in 2011
• Because earthquakes can destroy properties and can take lives of people, it is necessary to know how and where on Earth they are formed
• Earthquake


  Any sudden shaking of the ground that often occurs along geologic faults. The shaking results from a sudden release of energy to Earth's lithosphere.
• Focus


  Where the earthquake begins
• Epicenter


  The point directly above the focus, where the greatest damage takes place
• Types of earthquakes


  • Tectonic
  • Volcanic
  • Collapse
  • Explosion
• Tectonic earthquake


  Occurs when Earth's crust breaks or moves due to geological forces
• Volcanic earthquake


  Results from tectonic forces related to volcanic activities
• Collapse earthquake


  Usually occurs in underground mines, caused by seismic waves from rock explosions on Earth's surface
• Explosion earthquake


  Occurs from the detonation of any nuclear or chemical device
• Fault


  A fracture found between two blocks of rock on Earth's crust where compression and tension forces cause displacement of the rocks. It is the "weak point" where pressure on Earth's crust is released.
• Types of faults


  • Normal fault
  • Reverse fault
  • Strike-slip fault
• Hanging wall

  A block usually found above the fault plane
• Footwall


  A block usually found under the fault plane
• During an earthquake, the shaking of the ground produces seismic waves that travel to different parts of Earth and is recorded using seismographs
• Types of seismic waves

  • Surface wave
  • Body wave
• Body waves travel faster than surface waves