Download Topic 5

CHAPTER 5 - TOPIC
5 – EARTHQUAKES
Name: __________________
1. Seismologists study earthquakes by reading seismographs. The report that is printed out is
called a seismogram.
A seismometer is a special machine scientists use to measure earthquakes magnitude and are
attached to bedrock. Please describe how it works.
A machine attached to bedrock (where it is sturdy and stable). When an earthquake happens, a
pen attached to a lever moves. The pen records the results on a rotating drum. The larger the
line, the greater the earthquake.
2. What is a Richter scale? p.396
A scale used to describe the magnitude of an earthquake. Each time we go up 1.0 on the Richter
scale, the strength of the earthquake increases about 30 times.
3. Define seismic waves – energy waves that travel outwards from the source of the earthquake
(the FOCUS)
aftershock – smaller ground movements that come after the first earthquake
4. Types of E-Quake Waves
Type of WAVE
Key Info (time/travel thru/damage?)
1. Primary Waves (P – Waves)
-
2. Secondary Waves (S – Waves)
- faster than surface but slower than
primary
- can pass only through solids
- medium amount of damage
3. Surface Waves
-
fastest waves
weakest
pass through all solid/liquid/gas
least amount of damage
slowest waves
strongest
pass through only solids
most amount of damage
5. Why is it important to know that some waves go through liquid and others do not?
- We need to consider these aspects when designing buildings and deciding where to build
6. It is possible to determine the location of an earthquake by the intervals between P and
Secondary waves. The further apart they are the farther away the earthquakes. p.399
7. Please copy the diagram on p. 399 and define
focus – where the earthquake begins inside the earth
epicenter – where the earthquake originates on the surface of the earth. Directly above the
focus.
8. Rock Mov’t in E-qukes p. 403
The rock in the Earth’s crust is under pressure from tremendous forces causing rock to bend or
stretch.
If the pressure is too great, the rock break suddenly, creating a fault.
9. Please sketch and briefly describe the three types of faults on p. 403?
Fault
Normal Fault
Reverse Fault
Strike-Slip or
Transform Fault
Tension
Compression
Shear
DIAGRAM
FORCES
What occurs?
Plates stretch apart and The rock is squeezed
break, valleys will
by the movement of
form
the plates, forcing
them up and over
other rocks
The rocks have many
bumps and bulges on
them. They become
twisted and strained and
eventually break
10. Why does a rigid structure break during earthquakes? p. 404
They have very little flexibility/give within the joints of the structure.
11. What is a Tsunamis? p. 405 (liquefaction)
A large wave the has been created by an earthquake in the ocean or the sea (Ex. Japan)