3.a measuring earthquakes

Question 1

what is the richter scale ?

Answer 1

• Logarithmic - Every one point scale is a 10 fold increase than the one below .
• Mathematical device to compare the size of earthquakes.

The magnitude is determined from the logarithm of
Micro earthquakes = 2.0 or less
Great earthquakes = 8.0+

9.4 2004 boxing day earthquake

Question 2

example of richter scale for th 2004 boxing day earthquake

Answer 2

9.4

Question 3

what is the modified mercalli scale ?

Answer 3

• Measures intensity of earthquakes - uses roman numerals 1-12 - determine how strong a quake is
• If a higher number = more structural damage and people having to evacuate

Recording the impacts and responses
Subjective

Question 4

explain the moment magnitude scale

Answer 4

• Measures how much energy is released.
• Logarithmic an increase of 10 fold
• Seen as most accurate

Question 5

what are the two types of earthquakes?

Answer 5

• intraplate earthquakes
• quasi natural earthquakes

Question 6

intra-plate earthquakes outline

Answer 6

• 15% of earthquakes are away from plate boundaries
• Cultural stresses e.g china
• Old fault lines
• Isostatic rebound - ice age goes and the land becomes lighter rebounds up causing stresses and seismic activity

Question 7

what is isostatic rebound acossiated with intra-plate earthquakes

Answer 7

ice age goes and the land becomes lighter rebounds up causing stresses and seismic activity

Question 8

outline what quasi-natural earthquakes are

Answer 8

• Dam construction and a full reservoir can put weight on the crust
• Might reactivate and old fault or lubricate one
• Collapse of old mines or from fracking
• Can put pressure on crust causing stress and causing slippage
  E.g 1988 nepal earthquake