Name:_______________
Date:_______________
Period:_______________
Chapter 8: Earthquakes Study Guide
1. Earth's core is made of an alloy of _____Iron Nickel_________.
2. What is the elastic rebound hypothesis?
explanation for how energy is spread during earthquakes. As rocks on opposite
sides of a fault are subjected to force and shift, they accumulate energy and
slowly deform until their internal strength is exceeded. At that time, a sudden
movement occurs along the fault, releasing the accumulated energy, and the
rocks snap back to their original undeformed shape.
3. What affects the amount of destruction caused by earthquake vibrations?
Intensity and duration of vibrations, nature of the surface material, design
structures
4. What is a seismograph?
An instrument that measures and records details of earthquakes, such as force
and duration.
5. What are P waves?
Can travel through gas, liquid and solids
6. What is the major fault line closest to us?
San Andreas Fault
7. Which types of areas are most damaged by an earthquake?
Areas near fault lines
8. Why is the Earth's inner core solid?
The immense pressure at the inner core causes it to remain solid even though
it is hotter. The outer core is under less pressure so it remains liquid even
though it is cooler.
9. What is the crust?
Also known as the lithosphere. The thin outermost layer of the Earth,
approximately 1% of the Earth’s volume, that varies in thickness.
10.
What are the layers of the Earth? Crust, Mantle, inner core, outer core
11. What is liquefaction? Liquefaction is the name given to the process that
converts a solid soil mass into a liquid.
12. A tsunami can occur when there is vertical movement at a fault under __the
ocean floor_.
13. Which seismic waves compress and expand rocks in the direction the waves
travel? P Waves
14. A succession of ocean waves set in motion by a submarine earthquake is called
a _____tsunami____.
15. Which seismic waves travel most rapidly? P Waves
16. Which fault did the San Francisco earthquake of 1906 occur along? San
Andreas Fault
17. What are the causes of Earthquakes? Movement of plates
18. What are the characteristics of S waves? Slower than P waves, "second" to
arrive hence "secondary". Conducted as a shearing motion. Will not travel
through liquids or gas because these materials lack shear strength.
19.
When an earthquake occurs, energy radiates in all directions from its source,
which is called the ____focus_______.
20. Why do earthquakes often cause damaging fires? Earthquake vibrations can
break gas lines, water lines, and electrical lines.
21. What is the Moho? the boundary between the Earth's crust and the
underlying mantle
22. Which scale are scientists now using to represent the total energy involved in an
earthquake? Moment magnitude
23. Long-range earthquake forecasts are based on the idea that earthquakes are
__random__.
24. Major earthquakes are sometimes preceded by smaller earthquakes called
__foreshocks_.
25. What is the minimum number of seismic stations that is needed to determine
the location of an earthquakes epicenter? Three seismic stations are needed to
find the epicenter of an earthquake because all three radial circles made by
the stations will only meet at one point. (example: if you only had to circles
they would meet at two different points)
26.
27.
28.
Which Earth layer are S waves NOT transmitted? Outer core
What is a fault? Fracture in earth
What is a shadow zone? an area of the Earth's surface where seismographs
cannot detect an earthquake after its seismic waves have passed
29. What is the earthquake's epicenter?
30. The slow continuous movement that occurs along some fault zones is referred to
as __creep____.
31. What are the two types of surface waves? P and s waves
32. What is a seismogram? A record produced by a seismograph
33. Which seismic waves are most destructive? Surface waves
34. How is the distance between a seismic station and the earthquake epicenter
determined? By the arrival of P and S Waves
35. What is a landslide? The sliding down of a mass of earth or rock from a mountain
or cliff.
36. The adjustments in the plates that follow a major earthquake often generate
smaller earthquakes called __aftershocks_____.