Monday, May 16, 2011

2.2 Questions

1) Landslides involve the movement of a mass of rock or sections of the Earth's crust under the force of gravity.

2) Main causes of landslides are natural hazards - heavy rainfall, vibrations from the earthquake or undercutting of banks and cliffs from waves or rivers.

3) Human actions also causes landslides, the building of roads & railways on hillsides make them more vulnerable during heavy rainfall, stripping of vegetation and building man-made hills.

4) Earthquakes are the way earth releases stress. The force of earthquakes are measured on the Richter scale

5) Cause of earthquakes in Australia is intra-plate tension where movements occur along cracks or faults in the Earth's crust.

7) The Newcastle earthquake killed 13 people, injuring more than 120 and 40000 buildings damaged.

8) A landslide occurs by weather - rain, erosion where as an earthquake is large on scale, and a landslide often only travels for a few miles.

9) A tsunami is when an earthquake which occurs under the sea and creates a powerful wave.

10) Three events that will cause a tsunami are earthquake, landslides or volcanos

11) A tsunami is formed when the earth shakes lifting million's of tonnes of water, move in big flat waves across the ocean however in the deep sea under the surface is a big wall of water that can reach 800 kph. Tsunamis became hazardous as they reach shallow water, the tsunami slows down and the wall of water starts building which can reach a height of 30 feet or more.

12) Three warning  sings of a tsunami is the sudden re-treat of water, feeling of an earthquake and a large roar of water.

13) The Indian Ocean Tsunami was caused by under ground earthquake measuring 9.3

14) Australia has 23 automated earthquake monitoring stations. It took only 20 minutes for the 2004 Indian Ocean earthquake to be detected.

15) As a tsunami enters shallow water they slow down to about 40 kmph, as there is speed behind the the water it starts building up reaching 30 feet in height.

16) The UN responded to the 2004 tsunami by coordinating the development of a tsunami warning system for the Indian Ocean

17) Ted Bryant, a Wollongong University geoscience professor studies natural hazards and warns that tsunamis trigged by New Zealand's alpine fault line could strike NSW as often as once every 500 years.

18) i: The approx lat and long of the epi-centre of the 04 tsunami is 15 degrees north & 91 degrees east.

b)i: 2 hours

ii: 9 hours

iii: 5 hours

iv: 10

19) Thredbo Avalanche!

Thredbo was knocked by a devastating earthquake during the peak skiing season however there were luckily no deaths only a few injuries which is a relief for the qualified staff who have never seen an avalanche at Thredbo before.

The landslide has forced the closure of the whole mountain and were not sure how long it will take for the runs to be cleared and open, most luckily they will be closed for a while in case another avalanche occurs.

Many trees were battered down by the fierce force of the avalanche. Ski lifts are also broken, huts destroyed and hospitality areas will need a clean out.

The avalanche will have a big impact on the local community on Thredbo. As it is the peak skiing season the locals are actually going to making and losing money. If people decide to stay a shop owner or a restaurant owner will be bringing in quite a sum however for shop owners who depend on the strong skiing season they will be hurt the most.

The Thredbo avalanche will go down in the books for being the biggest landslide in Australia.

Tim Wells reporting for the NY Times

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