For this key question you need to know a case study of an earthquake in a rich part of the world and one from a poorer area – their specific causes; primary and secondary effects; immediate and long-term responses – the need to predict, protect and prepare. Contrasts in effects and responses will be clear.
Northridge, USA Sichuan, China Key Facts
- 17 January 1994 at 4.30am
- Lasted 10-20 seconds
- 6.7M on the Richter scale
- 12 May 2008 at 2.28pm
- Lasted 2 minutes
- 7.9M on the Richter scale
Causes Caused by a blind fault on the San Andreas Fault (conservative boundary). Friction builds up as the two plates move past each other and pressure is eventually released as an earthquake. Caused by movement on the Longmenshan Fault (destructive boundary between Eurasian and Indo-Australian plates). Friction builds up as the two plates move past each other and pressure is eventually released as an earthquake. Primary effects
- Buildings and highways collapsed
- Landslides triggered in surrounding mountain areas
- Gas and water mains damaged
- Liquefaction in the upper San Fernando Valley
- 57 people killed
- Buildings collapsed
- Half of the telecommunications in the province went down.
- 69,172 deaths
- Landslides
- Millions of livestock were killed and a large amount of crops were destroyed.
Secondary effects
- People trapped and injured by collapsed buildings (9,000 injured)
- Roads blocked and houses damaged by landslides especially in the Pacific Palisades area
- Fires caused by broken gas pipes
- Scoreboard at Anaheim Stadium collapsed onto several hundred seats
- Over 15,000 aftershocks also occurred casuing further
- 158 relief workers were killed by landslides
- Contaminated drinking water
- Impacts on the economy
- Aftershocks caused further deaths and collapsing buildings.
- 5000km pipes damaged
- 1300 water treatment works destroyed
- 5.46 millions homes destroyed and 21.0 million homes damaged
- 7000 schools destroyed
- Roads blocked by landslides
- Cost estimated at $75 million
Immediate responses The area was declared a federal disaster by President Clinton which allowed hundreds of workers from the Federal Management Agency (FEMA) were deployed to Southern California to help the communities recover.
Some areas in the affected area had not been reached within 30 hours after the disaster however access was impossible. Twenty helicopters were assigned to rescue and relief efforts and troops began parachuting in to assess the siutation whilst others hiked on foot. Thousands of army troops were deployed after the earthquake and large-scale efforts were made to free trapped survivors from collapsed buildings. On 14th May China requested international help. Donations to the Red Cross exceeded £100 million in the fortnight after the earthquake. Much of this went to running survivors camps – food, medicine and doctors, tents with mattresses and volunteers.
Long-term responses More than 600,000 applied for state and federal disaster assistance, and FEMA spent millions of federal money helping the area recover. The United States Geological Survey (USGS) has set up an experiment in Parkfield to record all ground shaking in an attempt to help build data to predict future earthquake. One hundred million temporary houses were built for those made homeless and the Chinese government has pledged $10million rebuilding fund and banks wrote off debts owed by survivors who did not have insurance.
Predict, prepare, respond
To try and reduce the damage caused by earthquakes you can implement management strategies to predict earthquakes, prepare for them and then respond to them. There will be significant differences in these strategies for MEDCs/LEDCs due to differing levels of wealth.
Predict:
Although you cannot predict the exact timing of an earthquake you can monitor them to establish where they are most likely to happen and to provide some kind of forecast so that preparation strategies can be implemented to reduce damage. Methods include:
- Using seismometers and seismographs to monitor movement within the Earth’s crust
- Plotting timing of earthquakes to look for possible patterns
- Mapping the location of earthquakes to locate earthquake zones
- Observing natural phenomena which can sometimes indicate the likelihood of earthquake activity (e.g. animal behaviour)
More information on predicting earthquakes
Prepare:
Although we can’t accurately predict the timings of earthquakes we can implement extensive preparation strategies to reduce damage when earthquakes do occur.
- Build earthquake proof buildings that will move with the earthquakes rather than collapsing
- Building regulations – avoid building on unstable ground to avoid liquefaction
- Education – practise what to do in the event of an earthquake e.g. the Great California ShakeOut
- Strengthen bridges and roads to prevent them from collapsing
- Emergency services planning to ensure they are fully trained and efficient during a disaster
- Automatic shut off switches for gas, electricity etc to prevent fire
- Earthquake Preparedness Now video depicting the impacts of a hypothetical but plausible earthquake in Southern California, USA.
Respond:
Wherever a strong earthquake hits immediate emergency aid is needed in the affected areas. Specialist rescue teams with sniffer dogs and lifting equipment, medical teams with field hospitals etc. Richer countries can provide this for themselves whereas poorer countries have to rely on international aid.
In the medium term people need to be able to return to their normal lives. Repairing and replacing what has been lost is essential as well as restarting economic activity. In LEDCs aid needs to be changed from short-term emergency aid to long-term development aid.
As you cannot accurately predict earthquakes the only effective long-term response is effective preparation. Emergency services need to be trained and ready: disaster relief plans need practise.