1. Earthquakes vocabulary review

2. Huge ocean wave produced by displacement of the sea floor.
Tsunami
Huge ocean wave produced by displacement of the sea floor.

3. The difference between the arrival times of the P and S waves.
Lag time
The difference between the arrival times of the P and S waves.

4. Seismic waves that travel through Earth’s interior
sill
dike
stock
neck
Body waves
Seismic waves that travel through Earth’s interior

5. A numerical scale of earthquake magnitude.
Richter scale
A numerical scale of earthquake magnitude.

6. The central, horizontal line running through the seismogram.
Baseline
The central, horizontal line running through the seismogram.

7. Rigid outer shell of Earth, 7 to 125 km thick
lithosphere
Lithosphere
Rigid outer shell of Earth, 7 to 125 km thick

8. The point on Earth’s surface above the focus.
seismic
fault
footwall
headwall
Epicenter
The point on Earth’s surface above the focus.

9. A layer of Earth beneath the lithosphere.
Asthenosphere
A layer of Earth beneath the lithosphere.

10. The height of the wave above baseline.
Amplitude
The height of the wave above baseline.

11. Anticline
An upward arching fold.

12. Scale expressing intensities of earthquakes in Roman numerals (I-XII).
Mercalli scale
Scale expressing intensities of earthquakes in Roman numerals (I-XII).

13. Type of fault where hanging wall moves down relative to the footwall.
Normal fault
Type of fault where hanging wall moves down relative to the footwall.

14. The record of earthquake motion recorded by a seismograph.
Seismogram
The record of earthquake motion recorded by a seismograph.

15. A measure of energy released during an earthquake.
Magnitude
A measure of energy released during an earthquake.

16. A fault where the hanging wall moves up relative to the footwall.
Reverse fault
A fault where the hanging wall moves up relative to the footwall.

17. A fault in which movement is parallel to the fault surface.
Strike-slip fault
A fault in which movement is parallel to the fault surface.

18. A seismic wave that travels on Earth’s surface.
sill
dike
stock
neck
Surface wave
A seismic wave that travels on Earth’s surface.

19. Benioff zone
Earthquake zone that slopes landward and downward away from the trench.

20. The point where seismic waves originate.
fault
footwall
headwall
Focus
The point where seismic waves originate.

21. A downward arching fold.
Syncilne
A downward arching fold.