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While researching a topic, a student has taken the following notes:
• Earthquakes start at a point called a "focus" and spread out from there as seismic waves.
• The two types of seismic waves that travel beneath Earth's surface are primary waves (P waves) and secondary waves (S waves).
• P waves travel more quickly beneath Earth's surface than do S waves.
• P waves compress and expand the ground, causing it to move backward and forward.
• S waves cause the ground to move from side to side.
• Earthquakes start at a point called a "focus" and spread out from there as seismic waves.
• The two types of seismic waves that travel beneath Earth's surface are primary waves (P waves) and secondary waves (S waves).
• P waves travel more quickly beneath Earth's surface than do S waves.
• P waves compress and expand the ground, causing it to move backward and forward.
• S waves cause the ground to move from side to side.