2.  Earthquake = the shaking and trembling that results from movement of rock beneath Earth’s surface  Focus = area beneath Earth’s surface where rock under stress breaks and causes an earthquake  Epicenter = point on the surface directly above the focus

3.  A. Earthquakes produce vibrations called __Waves___.  B. Waves carry ___energy___.  C. Seismic waves are _vibrations__ that travel through _Earth__ carrying _energy__ released during an earthquake.

4.  D. Seismic waves carry _energy__ from an earthquake _away__ from the focus, through Earth’s _interior_ and across the _surface_.  E. Three main categories of Waves:  1 Primary Waves (P waves)  2 Secondary Waves (S waves)  3 Surface Waves

6.  F. The first waves to arrive are _Primary_ waves.  1. P waves _compress__ and _expand__ the ground.  G. After P waves come _Secondary_ waves.  1. S waves are seismic waves that _vibrate_ from Side to Side as well as _up_ and _down_.  H. When P waves reach the surface, some of them become __Surface_ waves.  1. Surface waves move more _slowly_ than P or S waves but they produce _severe_ ground movements.

7.  A. There are at least 3 different measures for rating earthquakes.  B. Three methods for measurement:  1. Mercalli Scale  2. Richter Scale  3. Moment Magnitude Scale  C. Mercalli Scale = Rate of the earthquakes on the level of damage at a certain place

9.  D. Richter Scale = rating of an earthquake’s magnitude based on the size of the earthquake’s seismic waves  1. magnitude is a number _geologists_ assign to an earthquake based on the earthquake’s __size_  2. the seismic waves are measured by a _seismograph_  E. Moment Magnitude Scale = a rating system that estimates the total energy released by an earthquake  1. the data helps scientists _infer_ how much _movement occurred along the _fault_ and the _strength_ of the rocks that broke when the fault slipped

11.  F. Comparing Magnitudes  1. An earthquake’s _magnitude_ tells Scientists how much _energy_ was released by the earthquake  2. Earthquakes with a Magnitude of 6 cause?  Moderate damage  32 times the energy of a Magnitude 5 Quake

13.  A. Geologists use _seismic_ waves to locate an earthquake’s epicenter.

14.  What is a tsunami? Page. 376  A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!