tectonics HW how EQs and tsunamis occur

Question 1

process of an earthquake

Answer 1

1. movements are preceded by a gradual build-up of tectonic strain, which stores elastic energy in crustal rocks
2. when the pressure exceeds the strength of the fault the rock fractures
3. this produces the sudden release of energy, creating seismic waves that radiate away from the point of fracture
4. the brittle crust then rebounds either side of the fracture, which is the ground shaking — the EQ felt on the surface

Question 2

process of a tsunami

Answer 2

1. an EQ rocks the ocean floor
2. displaces volume of water, pushing it up
3. Sets off an oscillation which develops underwater at great speed
4. sea water is sucked back from the shore
5. waves get bigger as water gets shallower

Question 3

What is the Hypocentre of the Earthquake?

Answer 3

the point within the earth where an earthquake rupture starts

Question 4

what is the epicentre of an earthquake?

Answer 4

the point at the surface of the earth directly above the hypocentre

Question 5

what are seismic waves?

Answer 5

waves that transmit the energy released by an earthquake

Question 6

what id a fault (tectonics)?

Answer 6

a fracture in the rocks that make up the earths crust

Question 7

what are plates (tectonics)?

Answer 7

massive slabs that make up the outer layer of the Earths surface and whose movement along faults triggers earthquakes

Question 8

definition of an earthquake

Answer 8

the shaking of the ground caused by sudden motions along faults or fractures in the earths crust