earthquakes
Terms
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- what is the focus
- the area beneath earths surface where rock that is under stress breaks, triggering an earthquake. the place where the earthquake starts
- what is the epicenter
- the point on the surface directly above the focus. the surface of the earth shakes hardest at the epicenter
- what are the three categories of seismic waves
- p waves, s waves and surface waves ( L waves ) An earthquake sends p waves and s waves. when these waves reach earths surface at the epicenter, surface waves develop.
- what is a seismic wave
- carry energy from an earthquake away from the focus, through earths interior, and across the surface. earthquake waves.
- what is a p wave
- are the fastest moving waves that arrive first cause particles to move back and forth in place moves through solids liquids and gases they contract and expand the crust in the direction they move.
- what are s waves
- move slower than p waves and are the second waves to arrive. cause particles in materials to move back and forth. Ex: shakes buildings side to side
- what are surface waves ( L waves )
- are the slowest moving waves cause the surface to rise and fall like ocean waves cause the most damage Ex: shakes buildings violently
- what is a seismograph
- an instrument that measures the strength of earthquakes
- whats a seismogram
- the record that the seismograph takes it has wavy lines
- what are three methods of measuring earthquakes
- Richter Scale, Moment Magnitude Scale, Mercalii Scale
- what is the mercalii scale
- rates an earthquake according to the level of damage of a given place. there are 12 steps. it uses roman numerals
- what is the Richter Scale
- rates an earthquakes magnitude based on the size of the quakes seismic waves. the waves are measured by a seismograph.
- what is the Moment Magnitude Scale
- estimates the total energy released by an earthquake.
- what do surface ( l ) waves move through
- solids