Geological hazards and disasters

Question 1

What is a geological hazard?

Answer 1

Hazards associated with movement of the earth plate tectonics for example tsunami and earthquakes

Question 2

What are types of geological hazards?

Answer 2

-Tsunamis
-earthquakes
-avalanches
-landslides
-volcanic eruptions
-sinkholes

Question 3

Crust? (earth)

Answer 3

earths outer of soils, mineral and rocks, 100km

Question 4

Oceanic Crust?

Answer 4

-subducted, thin, dense

Question 5

What is plate movement?

Answer 5

Shape of continent is in constant flux explaining geological hazards because of plate movement tectonics

Question 6

Divergent plate boundary?

Answer 6

-two plates move away from each other
-new crust form

Question 7

What is a rift?

Answer 7

A lowland region that forms when plate tectonics move apart

Question 8

What is a Volcano?

Answer 8

A crack, fissure, vent in earths surface where molten lava escapes

Question 9

Types of eruptions?

Answer 9

Explosive
-Short violent outbursts of lava
-produces tephra and clouds of gas

Effusive
-outpour of lava

Question 10

What are hotspots?

Answer 10

Activity is found away from plate boundaries and magma is driven up from strong convection current in mantle

Question 11

What is an earthquake?

Answer 11

Sudden violent shaking of the ground typically causing mass destruction as a result of movement within earths crust

Question 12

What causes earthquakes?

Answer 12

Internal stress at the edges of plate tectonics becoming a fault line. When stress is great enough the energy is released and the crust breaks

Question 13

Hazards caused by earthquakes?

Answer 13

-Rock avalanches
-ground shaking
-landslide
-tsunami
-damage to infrastructure

Question 14

What is the epicentre?

Answer 14

Place directly above an earthquakes focus on earths surface

Question 15

What is the Richter scale?

Answer 15

Measures the size of an earthquake
-using seismographs
-as mag on scale 10 gets progressively more dangerous

Question 16

What is the Mercalli intensity?

Answer 16

Seismic intensity scale used for measuring intensity of shaking by the earthquake

Question 17

What are intra-earthquakes?

Answer 17

Variations in temp, strength, depth of rock pressure

Question 18

Where do earthquakes occur?

Answer 18

Divergent and convergent plate boundaries and also transform boundaries

Question 19

Tsunami summary

Answer 19

Key process
-movement of energy in water
-energy underwater caused by earthquake

Question 20

Tsunami response

Answer 20

-sea walls
-flood gates
-get out of the way

Question 21

What is the process of an earthquake?

Answer 21

It starts when 2 tectonic plates collide, spread of rub against each other. For example the 2011 Japan earthquake when north American and pacific plates collided. This then caused a huge store up of energy then is released up to the earths surface.
During the earthquake violent shaking of the earth occurs and is often sudden. This results in the ground splitting apart and the environment being damaged or destroyed such as buildings shaking and falling down.
After an earthquake. Aftershocks of smaller earthquakes can occur which are usually less damaging and happen for a period of time after the main earthquake. Earthquakes may also cause tsunamis where water is gathered into a big wave.

Question 22

What is Seismicity?

Answer 22

-Refers to the geographical locations of earthquakes throughout history
-seismic activity along subduction zones is subduction zone seismicity

Question 23

How is a tsunami formed?

Answer 23

If ocean floor is ruptured by a earthquake, huge amounts of energy is released onto the water and it gathers into a huge wave called a tsunami. Deep ocean waves are usually smaller height but are very long. The wave travels 100km quickly over the shore and get significantly taller in height. If trough reaches the shore 1st then water is retreated back into a larger wave

Question 24

Responses: Tsunami monitoring technology?

Answer 24

20min from quake till tsunami hits
-DART buoys placed near fault line
-2min delay from quake for info to reach warning centre
-buy time to evacuate and prepare

Question 25

Mantle? (earth)

Answer 25

Molten and semi molten rock

Question 26

Outer core? (earth)

Answer 26

Liquid

Question 27

Inner core? (earth)

Answer 27

Solid

Question 28

Continental crust?

Answer 28

-Not subducted, thick, less dense

Question 29

Convergent plate boundary?

Answer 29

continental and oceanic plates collide
-oceanic plate overridden by continental plate

Question 30

Transform plate boundary?

Answer 30

-two plates slide pass one another at locations