Human Activity and Earthquakes

Question 1

Why are earthquakes some of the most dangerous hazards to exist?

Answer 1

As some earthquakes have occurred long fault lines that scientists didn’t know existed until the earthquake occurred.

Question 2

How can human activity trigger earthquakes?

Answer 2

Bu constructing enormous structures such as large dams which retain great reservoirs of water it has increased seismic activity in the area because of the weight and pressure on the Earth.

Question 3

EXAMPLE.

How has underground nuclear testing triggered earthquakes?

Answer 3

In 1968, underground testing of a series of 12,000 ton bombs in Nevada set off 30 minor eathquakes in the area following 3 days.

Question 4

EXAMPLE.

How has the building of a dam caused earthquakes?

Answer 4

In 1935, the Hoover Dam from Lake Mead dammed the Colorado River. As the lake filled and underlying rock adjusted the increased amount of water of over 40km3 caused 6000 minor eathquakes within 10 years

Question 5

Name 3 ways human activity can cause earthquakes?

Answer 5

The injection of liquid into underlying rocks.
Underground nuclear testing.
Increased load onto unstable surfaces.

Question 6

How does injecting liquid into underlying rock cause earthquakes?

Answer 6

Lubricate and reactivate series of deep underground faults, which may have been inactive for a long period of time.