Earthquakes

• These waves are responsible for shaking the ground horizontally and vertically in an S-like pattern. 

  Love waves
• The area under the earth where the slippage originates is called?

  Hypocenter or focus
• The point on the Earth’s surface directly above the hypocenter.

  Picenter
• Are waves that travel through the interior of the Earth.

  Body waves
• Primary waves are the fastest seismic waves and can travel through solid, liquid, and gas. These waves push and pull the rocks in the direction the wave is traveling. They are also called?


  Compressional waves
• Secondary waves cause the rocks to shake up and down at right angles to the direction of the traveling wave. S waves are slower than P waves and can only travel through solids. Because of this, S waves cannot propagate through the liquid outer core. They are also called?


  Shear waves
• When slippage happens, the stored energy is released as. The seismic waves travel through the earth and cause it to shake. These waves can be classified into two types: 


  Body waves and surface waves
• What are the two types of seismic waves?

  Body waves and surface waves
• Can only travel on the surface of the Earth. These are the waves that can cause tremendous damage. 


  Surface waves
• What are the two types of surface waves?

  Love waves and rayleigh waves
• What are the two types of body waves?

  Primary waves and secondary waves
• These waves move in a rolling motion similar to ocean waves. 

  Sometimes, before the main earthquake or mainshock, smaller and weaker quakes called foreshocks occur. 


  Rayleigh waves
• Is the study of earthquakes?

  Seismology
• Refers to the qualitative measurement of ground shaking at a particular location, depending on the damage to property, life, and nature.

  Intensity 
• Refers to the quantitative measurement of energy released at the earthquake’s source.

  Magnitude
• Is used in countries like the United States. 

  Modified Mercalli Intensity Scale 
• This scale was developed by the Philippine Institute of Volcanology and Seismology (PHIVOLCS) as a response to the devastating 1990 Luzon Earthquake.

  PHIVOLCS Earthquake Intensity Scale (PEIS)
• Before, most commonly used scale for measuring the magnitude, which measures the amplitude of the largest seismic wave on a seismogram.

  Richter Scale 
• Now, seismologists uses which measures the total energy an earthquake releases.

  Moment Magnitude (Mw) Scale
• The next most tectonically-active seismic belt, where 17% of the world’s earthquakes occur.

  Alpine-Himalayan Belt
• The rest of the earthquakes occur along in the Atlantic Ocean.

   Mid-Atlantic Ridge 
• Nearly 81% of earthquakes occur in a tectonically-active region called? and also known as the Ring of Fire.

  Circum-Pacific Belt
• The contact between the two interacting plates is called? and which can produce earthquakes of Mw 9.0 and above.

   Megathrust faults
• Earthquakes caused by the eruption of volcanoes are called volcanic earthquakes. Generally, small earthquakes called collapse earthquakes occur when underground caves or mines collapse. The detonation of explosives can also cause earthquakes called explosion earthquakes. The most common type of earthquake, tectonic earthquakes, are caused by fault movement.
• Result from tensional forces that pull the two slabs apart. They are also known as tensional, gravity.

  Normal faults
• Results from compressional forces pushing the two slabs together, shoving the hanging wall above the underlying block. These are also known as thrust, compression.

  Reverse faults
• Blocks move horizontally to one another due to shearing forces.


  Strike-slip fault
• Left-lateral strike-slip faults 

  (Sinistral faults)
• Right-lateral strike-slip faults 

  (Dextral faults) 
• Combining shearing and tensional or compressional forces would result?

  Oblique-Slip Faults
• Is the sudden sinking of the Earth’s surface due to the movement of the earth underneath. 

  Subsidence
• Is similar to subsidence but occurs when sediments are saturated with water.

  Liquefaction
• In enclosed bodies of water such as lakes or reservoirs, waves may occur called? These are oscillating waves that produce major fluctuations in the water level, depending on the strength of the earthquake.

  Seiches 
• Once tsunamis reach shallow waters, wave height increases dramatically and can reach up to 30 m, like what happened in the 2004 Indian Ocean Mw 9.1 Megathrust Earthquake in?


  Sumatra, Indonesia