| The scientists compared the time it took seismic waves generated by nearly identical earthquakes to travel through the Earth's inner core. |
| For three years, the seismometers recorded how seismic waves from hundreds of earthquakes worldwide bounced through the mantle. |
| Just as seismic waves travel through Earth, infrasonic waves travel through the air. |
| These seismic waves in the crust are what people feel when they experience an earthquake. |
| A co-worker, Dave Snyder, is checking one of the instruments that is used to record seismic waves and is putting it in a cooler to keep it warm. |
| Like bats using echolocation to navigate through the night, geophysicists rely on seismic waves for information on the Earth's deep interior. |
