Sichuan Earthquake - H Flashcards
What are disasters caused by
Lack of preparedness within communities, and by the inability of political authorities to organise and provide resources to guard against or withstand hazard effects. In this sense, there is little that is ‘natural’ about hazards - understanding environmental issues book
When was the earthquake
2008
What was the magnitude
7.9
What was the death toll
69,185 (officially dead)
What was the toll for missing and presumed dead
Over 18,000
Where was the earthquake
Sichuan province located in the centre of south China. This is a rural area, unaffected by china’s economic growth
What is the tectonic history of the area
225 million years ago: Africa, India and Antarctica joined as one large southern continent known as Gondwanaland.
It broke: India moved 5-10cn per year northwards.
40 million years ago: collided with Tibet to form the Himalayas.
The Eurasian plate thickened (creating the Tibetan Plateau), gilded and cracking during the convergence worth the Indian Plate.
Parts of China are heavily faulted as there are cracks in the earths crust.
What is the tectonic setting
Eurasian plate and Indian plate margin
Continental/continental convergence
What was the cause of the quake
Tectonic stresses built up and stored energy was related, rupturing along the Longmenshan fault
Depth of focus
10km (very shallow)
Epicentre of earthquake
92km North-West of Chengdu in Wenchuan country
How many people like in the Sichuan Basin
100 million people
What is the lithololgy of the Sichuan basin
Unconsolidated sediment
What amplified the affect of the shaking
The unconsolidated sediment was prone to liquefaction
Where was the shaking felt
In Bangladesh, Vietnam and Taiwan
When did the string aftershocks continue until
August
How strong were some of the aftershocks
6 on the Richter scale
What were the primary economic effects
A cargo train carrying 13 petroleum tanks derailed in Hun Country, Gansu and caught on fire after the rail was distorted.
391 dams damaged by the quake.
5.6 million buildings collapsed - Seismic design code introduced in 1976 and most buildings were older than that.
21 million buildings damaged.
How many people were killed (primary)
Over 69,000
How many people were injured (primary)
Over 374,000
How many people listed as missing (primary)
18,222
How many people were left homeless (primary)
5 million (could be as many as 11 million) (the timing of the earthquake made this worse)
How much of roads were destroyed or covered by landslides (primary)
5300km
What were fractured or covered by landslides (primary)
Roads and several bridges and railway lines
How much water pipeline was destroyed (primary)
8000km
What was temporarily closed (primary)
Chengdu Airport and hospitals damaged
How many dams were weakened (primary)
2300
What were the secondary economic effects
Oil prices dropped over speculation that the demand from China would fall.
Cost exceeds $20 billion.
In Shifang, chemical plants collapsed killing hundreds and releasing toxic ammonia.
Loss of factories, hydro-electric power generation and tourist revenues - large impact on the economy.
What were the secondary social effects
Communications such as telephones were cut off.
Damaged road, rail and airport network hindered the rescue effort.
158 rescue workers killed in landslides.
What were the secondary environmental effects
6 pandas escaped from their enclosures in the Wolong National Nature Reserve. 2 pandas were injured and one was killed.
Rivers blocked by landslides forming ‘quake lakes’ (34 formed and risked flooding when dams collapsed)
The Food and Agriculture Organisation estimated that 32 million farm animals perished.
Hundreds of thousands of hectares of farm land left dry after irrigation systems damaged.
Two chemical factories collapsed in Shifang, releasing toxic gas.
What were the short term responses
Rapid emergency response from the Chinese Prime Minister visited the affected area with the UN Secretary General.
14,000 Chinese troops sent in by boat, on foot, by helicopter and parachute.
100,000 volunteers.
Rescue effort impeded by mountainous terrains and damaged roads.
Foreign governments and NGOd sent aid.
The WTO warned of the threat of disease due to lack of lean water and poor sanitation.
Terrorised camps estbalished.
Government declared a three day period of national mourning for quake victims.
250,000 residents evacuated.
2000 soldiers excavated earth from Lake Tanagjiashan (formed by landslide) to widen a drainage channel.
By June, 248 out of 254 roads were repaired.
Government made last minute changes to the route of the 2008 Olympic torch itinerary to include visiting the earthquake zone but even the Olympic spirit could not overcome the problems in the Sichuan province.
10.7 billion yen was donated by the Chinese.
What were the long term responses
Lack of reinforcement in school buildings meant that the floors collapsed on to each other, leaving little space for those trapped to survive. The government promised to crack down on the design of school buildings.
Beichuan, a town designated by the earthquake (80% of buildings destroyed and half the population killed) was not rebuilt, it has been left as a memorial to those who lost their lives.
Tourists now visit the ruined town.
Some buildings supported by probs to stop further collapse.
Remaining population were rehoused 12 miles away in a neighbouring town.
Because of the one child policy, many people lost their only child so the policy is being relaxed in the Sichuan area and the Chinese government was reported sending medics to reverse sterilisation operations.
What are key to trying to rescue the impact of earthquakes
The 3 Ps: prediction, protection and preparation
What is prediction
Involves trying to forecast when an earthquake will happen
Why do Japan try to monitor earth tenors
They have a belief that warnings can be given, but this did not happen at Kobe
Experts know when earthquakes are likely to happen, but what do they struggle at
Establishing when. Even looking at the time between earthquakes in a particular area does not seem to work. Also struggle to pinpoint exactly where along a plate margin they will occur.
What does protection involve
Building to an appropriate standard and using designs to withstand movement
What does preparation involve
Hospitals, emergency services and inhabitants practising for major disasters, including habitants drills in public buildings and a code of practice so that people know what to do to reduce the impact and increase their chance of survival
Why is preparation the main way in which earthquakes can be managed
Because they are currently impossible to predict or prevent
In Japan and the USA, how often do schools hold earthquake drills
Once a month, sometimes in earthquake simulation structures, and students are taught to ‘drop to their knees, over their heads and hold onto their desks’
When an earthquake occurs, what is the emergency response
Vital and met big domestically and internationally
Following the 2010 Haiti earthquake what were the emergency responses
National governments, international organisations and NGOs supported the Haitian government by providing military and disaster relief personnel, field hospitals and emergency facilities
Why are designing and engineering buildings that are life-saving important in the long term
The collapse of buildings is the greatest risk to human life
What have been put in place in high risk earthquake zones in Japan and the USA
Sophisticated engineering solutions e.g skyscrapers have been built on ball bearings, springs and padded cylinders which act like shock absorbers
For low cost, informal housing, what can prevent collapse
Simply strengthening the corners using wooden buttresses
Protection-earthquake proof building design
Computer controlled weights on roof to reduce movement.
‘Birdcage’ interlocking steel frame.
Fire resistant building material.
Roads to provide quick access for emergency services.
Rubber shock-absorbers to absorb earth tremors.
Foundation sunk into bed rock, avoiding clay.
Open areas where people can assemble if evacuated.
Automatic window shutters to prevent falling glass.
Steel framed that can sway during earth movements.
What are the 7 steps to earthquake safety according to the American Red Cross (an American approach to preparation)
Identity earthquake hazards in your home.
Create a disaster plan.
Create disaster supplies kit.
Identity and fix your buildings weaknesses.
During earthquakes - drop, cover and hold.
After earthquakes - check for injuries and damage.
When safe, continue to follow your disaster plan.
