Science

• Tsunami


  A Japanese word pronounced as "soo-nah-me" which means "wave in the harbor"
• Tsunamis are sometimes misnamed as "tidal waves"
• Tsunami


  A massive ocean wave triggered by underwater earthquakes or volcanic activity, posing a serious threat by flooding coastal areas with powerful and destructive force
• How a tsunami is formed

  1. Faults are seen not solely on land but also under the ocean

  2. When a fault at the ground of the ocean swiftly moves, the water over it can be stirred

  3. An abrupt force from an underwater fault can create a wave named a tsunami
• Earthquakes


  If the earthquake occurs in the ocean, it can push up powerful waves, known as tsunamis
• The sudden upward or downward movement of the seafloor during an earthquake creates large tsunami waves
• Not all fault movement underneath the sea will create a tsunami
• Faults that move during a horizontal direction or sideways will not result in tsunami
• Causes of tsunami

  • Earthquake
  • Icefalls
  • Volcanic eruptions
  • Heavy rainfall
  • Cosmic impacts
  • Landslides
• Earthquake as a cause of tsunami


  • The sea floor abruptly deforms and displaces the sea water lying above
  • Large vertical movements of earth's crust can occur at plate boundaries which are called "faults"
• Volcanic eruptions as a cause of tsunami


  Volcanic eruptions create disturbance undersea by creating great force and thus generate tsunami
• Icefalls as a cause of tsunami

  If their height is larger than their width, they can be unstable following break off and roll over, potentially creating a giant wave
• Heavy rainfall as a cause of tsunami

  Heavy rainfall cause overflow of water and generate tsunamis
• Cosmic impacts as a cause of tsunami

  When a meteorite or an alien force impact the ocean area disturbing the water from above, tsunami is caused
• Landslides as a cause of tsunami

  When there is large landslide in mountains in the sea, the tsunami is caused and effect fell at bays
• 72% of tsunamis are generated by earthquakes
• A disturbance that displaces a large water mass from its equilibrium position can cause a tsunami
• Our continent for the past many years has been only one continent called Pangaea
• The continents are above the tectonic plates that are moving
• Layers of the Earth

  • Crust (thinnest layer)
  • Mantle (thickest layer)
  • Core (innermost layer, made up of solid, liquid, iron, and nickel, classified into inner core and outer core)
• Tectonic plates


  Massive, irregularly shaped slabs of solid rock, generally composed of both continental and oceanic lithosphere
• Plate boundary


  A three-dimensional surface or zone across which there is a significant change in the velocity (speed or direction) of motion of one lithospheric plate relative to the adjacent lithospheric plate
• Earthquake


  The shaking of the surface of Earth due to the sudden release of energy in the Earth's crust
• Fault


  Cracks in Earth's crust between two huge plates, a fracture or zone of fractures between two block of rocks, allowing the blocks to move relative to each other
• Parts of a fault

  • Footwall (block positioned under the fault plane)
  • Hanging wall (block above the fault plane)
  • Fault plane (planar surface along which there is slip during an earthquake)
• Dip-slip fault


  • Inclined fractures where the blocks have mostly shifted vertically, if the rock mass above an inclined fault moves down it is a normal fault, if the rock above the fault moves up it is a reverse fault
• Normal fault


  • Develops in areas where the land is pulling apart or stretching, one block of land slips downward in relation to the other block
• Reverse fault


  • Occurs in areas undergoing compression
• Strike-slip fault


  • Fault plane is usually vertical, with lateral or horizontal forces carrying the sides past each other
• Oblique-slip fault


  • Caused by a combination of shearing and tension or compressional forces, has both dip-slip (normal or reverse) and strike-slip components
• Active fault


  • Known to have recently generated earthquakes within the last 10,000 years, and may still continue to generate earthquakes
• List of active faults

  • Marikina Valley Fault
  • Western Philippine Fault
  • Eastern Philippine Fault
  • Southern of Mindanao Fault
  • Central Philippine Fault
• Inactive fault


  • Do not show signs of ever having generated an earthquake in the last 10,000 years, but may possibly still generate an earthquake in the future