12. Impacts of Earthquake

Impacts of Earthquakes

Source: adapted from https://www.bbc.co.uk/bitesize/guides/ztp2k7h/revision/3

What are the risks associated with living in earthquakes zones?

A. Disruption of services

• An earthquake can isrupt services such as the supply of electricity, gas and water and potentially affect a large area

• Vibrations on the ground can snap pipes and break cables which may cause the outbreak of fires

• Communications services such as television broadcasts and telephone connections may also be lost

• The earthquake in Kobe, Japan, in 1995 disrupted electricity, gas and water supplies to about a million of Kobe city’s 1.4 million residents

B. Landslides

• The shaking of the ground during earthquakes can weaken the slopes of hills and mountains, causing landslides

• Landslides are rapid downslope movements of soil, rock and vegetation

• For example in 1970, an earthquake in Peru destabilized the slopes of Mount Huascaran and triggered a massive landslide

• The landslide travelled at more than 160km/h and completely flattened the town of Ranrahirca within seconds causing 18 000 death

C. Destruction of properties and infrastructure

• Earthquakes can cause widespread destruction to many homes

• People may be without homes after the disaster and have to reside at temporary shelters

• The earthquake in Tohoku, Japan caused a tsunami to travel 10km inland and destroyed homes, resulting in severe shortage of housing

• Earthquakes may cause cracks to form in infrastructure such as roads and bridges

• Transportation can be disrupted, as it is unsafe to use the damaged roads

• For example, the the earthquake in Kobe, Japan has caused many places in city to become inaccessible or difficult to reach

D. Loss of lives

• Earthquakes and their associated hazards often threaten the lives of those living in earthquake zones.

• The 9.0 magnitude earthquake which struck Tohoku, Japan in March, 2011 cause 28,000 people to lose their lives. The 7.0 magnitude earthquake which struck Haiti in Jan 2010 cause as many as 300,000 to lose their lives.

E. Tsunamis

• Tsunamis can travel long distances and causes widespread destruction at coastal areas when it sweeps inland

• In 2004, a 9.2 magnitude triggered a tsunami with waves spreading throughout the Indian Ocean

• The tsunami caused damage to coastal communities in 12 countries

• The most damage was experienced in the low-lying areas of western Sumatra, Indonesia

• The tsunami waves went in as far inland as 10km and houses were swept inland or out to sea.

The 11 March 2011 Tsunami which hit Japan resulted in more than 28000 deaths.

Earthquakes can trigger tsunamis, explain how a tsunami is formed from the bbc website and watch the video below:

http://www.bbc.co.uk/schools/gcsebitesize/geography/natural_hazards/tsunamis_rev1.shtml

When an earthquake happens on the ocean floor, water is displaced and form a gigantic wave, When the waves reach shallower water near the coast, the friction cause it to slow down and increase in height, to as high as 15 metres.

2004 Indian Ocean Tsunami http://www.coolgeography.co.uk/GCSE/AQA/Restless%20Earth/Tsunamis/Tsunamis.htm

Download the ST Stars e-book from https://play.google.com/store/apps/details?id=com.sph.ststar&hl=en and then the e-book "Ocean's fury" for free.

Some extracts from the e-book on ocean's fury below:

Look at how a tsunami is formed:

Look at the impacts of the tsunamis from the photos taken in Jan 2005 and after the areas recover in 2014.

The warning system set up to prepare and mitigate impacts from tsunamis.

Points to ponder:

1. What cause a tsunamis?

2. What are the impacts of a tsunamis? Read more about impacts of tsunamis @ http://www.sms-tsunami-warning.com/pages/tsunami-effects#.Vg9gi_mqqko

3. What are the short-term and long-term responses?

4. How do they prepare for tsunamis?

A major earthquake with a magnitude 7.7 struck off Papua New Guinea on Monday and triggered a tsunami warning. Find out from the news article below the impact. http://www.channelnewsasia.com/news/asiapacific/tsunami-threat-has/1755694.html