Earthquakes and volcanoes: impacts of tectonic hazards

Question 1

What are the effects of the ground shaking, soil liquefaction and landslides?

Answer 1

• destroys ecosystems (ruptures chemical and oil factories, causing pollution)
• destroys infrastructure (weakens buildings, bridges,etc, causing them to collapse)
• disrupts services (snap water pipes and electricity cables)
• causes injuries and fatalities (people can get trapped under collapsed buildings)

Question 2

What are the effects of tsunamis?

Answer 2

• seawater flooding
• fast moving waters carry large amount of debris, which could sweep infrastructure away
• snap water pipes and electricity cables
• sweeping waters can drown people

Question 3

How do tsunamis occur?

Answer 3

1. An undersea earthquake occurs, causing the seabed to be displaced
2. A large volume of water is lifted, forming waves of great wavelengths and low heights
3. The waves travel towards the coast at high speeds
4. As waves approach the coast, there is greater friction with the shallower seabed, slowing the waves down
5. The waves get closer together and increase in height
6. The sea may recede before a tsunami as the sea fills the void caused by the displacement of the seabed

Question 4

What are the effects of tephra?

Answer 4

• ash can be carried thousands of kilometers away, polluting areas
• ashfall can accumulate on the roofs of houses
• damage plane engines
• hit people, injuries and loss of lives

Question 5

What are the effects of volcanic gases?

Answer 5

• kill wildlife and destroy vegetation
• acid rain, corroding buildings and infrastructure
• cause headaches and even death

Question 6

What are the effects of lava flows and pyroclastic flows (hot cloud of gas,ash and rocks)?

Answer 6

• lava can flow a distance, destroying forests and ecosystems
• burn homes and properties
• destroy electricity cables and water pipes

Question 7

What are the effects of lahars (mudflows comprising of water and volcanic ash) and volcanic landslide (loose volcanic material)?

Answer 7

• cover forests, hardening like concrete
• cover houses
• block roads and railways
• bury people in their houses

Question 8

What are the benefits of volcanic eruptions and living near volcanoes?

Answer 8

• farming with fertile soil
• extraction of precious materials and fossil fuels
• harnessing of geothermal energy
• tourism activities