Occurence of Earthquakes and faults

• Are ground vibrations that occur when blocks of rock within the earth move suddenly and release energy.

  • Earthquake
• explains the occurrence of earthquakes.

  • Elastic Rebound Theory
• when the rock can no longer withstand the pressure

  • Elastic Deformation
• The return of the rock to its original shape after elastic deformation

  • Elastic rebound
• is a spot within the crust where a fault shifts or moves.

  • focus
• is the spot on the ground where the movement or shaking is felt during an earthquake

  • epicenter
• Directly above focus also known as

  • Hypocenter
• when large blocks of rock break and move past each other is called

  • fault
• The blocks of the rock on either side of the fault are

  • fault blocks
• the location where two fault blocks meet

  • fault plane
• blocks above the fault plane are the

  • hanging wall
• while the one below the fault plane is the

  • footwall
• which is the steepness or the inclination of the fault plane

  • fault dip
• is the fault dip is inclined relative to the horizontal surface of the ground

  • dip-slip fault
• is a type of fault formed when the stress on the rock pulls apart causing it to stretch

  • Normal Fault
• a type of fault is created when the stress pushes the rocks towards each other

  • reverse fault
• is a special type of reverse fault wherein the fractures is nearly horizontal.

  • thrust fault
• the fracture on this type of fault is vertical

  • strike-slip fault
• is an ordinary feature on the oceanic crust

  • transform fault
• types of fault

  • dip-slip fault
  • normal fault
  • reverse fault
  • thrust fault
  • strike-slip fault
  • transform fault
• The philippine trenches

  • sulu trench
  • manila trench
  • negros trench
• faults are recorded by a measuring device called

  • seismograph
• if the fault no longer shows any activity for a million years it's called

  • inactive fault
• is a formerly inactive fault that is forced to move by tectonic plates

  • reactivated fault
• This system of faults caused by tectonic forces that compress the archipelago into what geophysicists call the

  • Philippine Mobile Belt
• The main fault that runs through almost all parts of the country is called

  • Philippine Fault System