Earth and space

• Earthquake- sudden vibration of the earth crust due to the release of energy from the internal part of the earth

  Main cause of seismic waves
• Primary or P-wave - fastest, compressional, back and forth motion, can travel through solids and liquids
• Seismic wave - mechanical disturbance that travels through the earth
• Secondary or S-wave - slower than p-waves, shear, sideways motion, cannot pass through liquid
• Intensity scale (Modified Mercalli) - measures how much damage was done by the earthquake
• Magnitude Scale (Richter) - measures the size of an earthquake based on the amplitude of the largest recorded seismic wave
• Earthquake is a sudden vibration of the earth crust due to the release of energy from the internal part of the earth.
• Faults produce earthquakes because energy from inside the earth makes the ground move, once friction is overcome a fault slips producing earthquakes.
• Normal faults cause extending of the crust.
• Friction between rocks prevents rocks from releasing the energy.
• Reverse faults form when the hanging wall moves upward relative to the footwall.
• Modified mercalli scale measures an earthquake's intensity.
• The intensity of an earthquake depends on the amount of damage it causes in an area.
• Body wave consists of primary and secondary waves.
• The most destructive seismic wave is the surface wave.
• Secondary waves can travel through the crust.
• Primary waves are detected first in the seismic station.
• Secondary waves can travel both liquid and solid.
• Secondary waves are slower than primary waves.
• The movement of rock particles as the primary wave passes is that the rock particles move back and forth parallel to the direction of the waves.
• If the primary waves passes through solid to liquid the velocity decreases.
• Tropical cyclones are most likely to develop in the Pacific Ocean.
• Warm river water is not a factor in the formation of a typhoon.
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