Text: Ch.3

Question 1

Most disastasrous earthquake in modern times was in ____ in 19__ when 255,000 people were killed in less than 6 mins

Answer 1

China, 1976

Question 2

The conseuences of an earthquake depend on 6 things

Answer 2

1. magnitude
2. depth
3. direction of fault rupture
4. distance from populated areas;
5. nature of the local earth materials;
6. engineering and construction practices

Question 3

Why does depth affect earthquake damage and causualties?

Answer 3

Different depths within the earth affects whether energy dissipates by the time the seismic waves reach the surface, resulting in less damage

Question 4

Infrastructure in Earthquakes: _____ and _____ infrsstructure is built affects it ability to withstand earthquakes

Answer 4

How and Where

Question 5

Earthquakes Defined

Answer 5

result from the rupture of rocks along a fault which is a fracture in Earths Crust. Rocks on opposite sides of a fault move suddenly, and energy is released in the form of seismic waves.
.Epicentre of the earthquake is the point on the surface of earth directly above the fault rupture
.Focus is the location of the initial rupture along the fault, directly below the epicentre
.At the instant of the rupture, seismic waves radiate outward in all directions from the focus

Question 6

magnitude

Answer 6

to express the ammount of energy an earthquake releases

intensity provides a measure of the effects of the earthquake on people and structures

Question 7

Earthquake ground motions are recorded by an instrument called _______

Answer 7

seismograph

Question 8

Richter scale

Answer 8

first quantitative magnitude scale
-quantified the magnitude of local(california) earthquakes as a logarithm to the base 10 of a maximum signal wave amplitude recorded on a then-standard seismogram at a distance of 100km from the epicentre

Question 9

____ ____ has replaced the Richter scale because..

Answer 9

Moment magnitude

• most commonly used measure of earthquake size which is determined from the area that ruptured along the fault plane during the quake, the ammount of movement or slippage along the fault, and the ridgidity of the rocks near the focus.
• an increase from whole number to the next higher one represents a 10-fold increase in the ammount of shaking and about a 32-fold increase in ammount of energy released

ex: comparing an M5 to M7 earthquake, the differences are much greater, energy released in 32x32, or about 1000 times greater

Question 10

Descriptive Adjectives for earthquake magnitude:

Give magnnitude level and place in order:

Strong=
minor=
Major=
giant
great=

Answer 10

1. Giant=9
   - are uncommon, 3 per century
2. Great=8
   - uncommon, 1 per year
3. Major=7-7.9
   - most damaging earthquakes, widespreas and serious damage
4. Strong=6-6.9
   - most damaging earthquakes, considerable damage but over a smaller area than a major quake
5. Minor=