13. Preparedness Measures
Let's examine the preparedness measures people put in place to cope with earthquakes and their associated hazards
Land use regulations
• Rules implemented to restrict developments in certain areas demarcated as highly unsafe.
• For example, in California, USA, all new buildings developments are not built across fault lines or areas at risk of liquefaction (saturated soil flow like liquid).
• Prohibition of building development along coast which are vulnerable to tsunamis
• Developments may be allowed only when protective barriers such seawalls facing the ocean are constructed.
• For example, these regulations are commonly implemented along the coasts of Japan and North America where the Pacific Ring of Fore is located.
• Regulations needed to be implemented in areas which may already be built-up or are privately owned.
• Government authorities acquire over the unsafe land and these strategies are costly
• Such strategies may not be effective as existing owners might be reluctant to give up land as they believe that another hazard would not happen.
Infrastructure
• Effective building design can reduce the collapse of buildings and minimize the damage caused by an earthquake. For example, the Taipei 101 in Taiwan is made of steel and reinforced concrete which can withstand earthquakes better than brittle materials such as non-reinforced concrete. It also has a damping device which act as counterweights moving in the direction opposite to the motion of an earthquake and thus prevent the building from swaying too much and collapsing. The foundation of the building is also reinforced by heavy metal bars as buildings with wide and heavy bases deceases the likelihood of buildings from collapsing.
• Base isolation bearings made of rubber or cushion can be placed between the ground and the building to absorb the force of the earthquakes and reduces the movement of the building. E.g. lead rubber bearings used at the Sabiha Gökçen International Airport.
• Supporting infrastructures in the area requires reinforcements from earthquake damage
• For example, roads and bridges can be built to resist the shaking of the ground so that they do not collapse, or can be easily repaired if collapse.
• Office buildings and factories to be fitted with trip switches that ensure all electrical points are switched off in the event of an earthquake.
• For example, in Japan, the machines in many factories automatically shut down when they sense earthquake vibrations.
• Large underground water tanks are emergency reservoirs for possible firefighting after an earthquake. For example, these water tanks are found in Tokyo, Kyoto and Kobe in Japan for such purpose.
• This measure may not be effective as it too costly to develop these earthquake resistance infrastructures and untested until earthquakes occur.
• Past earthquake events have demonstrated benefits of reinforced infrastructures such as fewer lives lost, faster rescue and evacuations and less money spent on recovery.
Emergency drills
• Help to create awareness and reduce levels of panic and irrational behavior during an earthquake event.
• Emergency drills include moving to safe locations, listening to instructions given by trained personnel and practising first aid.
• For example, people in Japan are involved in Disaster Prevention Day conducted on 1 September yearly to prepare them mentally on how to react to a disaster.
• Emergency procedures may not be effective as they require enough time for people to evacuate and earthquakes are difficult to predict.
Earthquake and tsunamis monitoring and warning systems
• Seismic risk maps show the likelihood of locations at risk of earth movements or liquefaction.
• However, this measure may not be effective as seismic risk maps only show frequency and magnitude of the earthquakes but not the time, location and magnitude of future earthquakes.
• Installing earthquake sensors in earth-prone zones helps to monitor the frequency of vibrations and detect possible developments of an earthquake.
• However, this measure may not be effective as it is costly to install and use
• Noise, lightning or device failure may interfere with the seismograph and result in false warnings being given
• An earthquake usually occurs seconds after a warning is sounded, thus this may not provide sufficient time for an evacuation
• Tsunami monitoring devices help predict tsunamis and are often linked to warning systems which are activated to warn people about the occurrence of a tsunami. For example, a network of pressure sensors, seismographs and deep ocean tsunami detectors are located in Hawaii, USA to monitor and forecast the path of tsunamis. However, this measure may not be effective as they are prone to give false alarms when waves are high. There is also little time to evacuate once an approaching tsunami is detected.
Early warning earthquake app in USA
Understanding how preparedness measures can help to mitigate the impact of earthquakes.
Abstract from “Vital Early Warnings Saved Lives in Jiuzhaigou Earthquake” Published on 15 Aug 2017
https://reliefweb.int/report/china/vital-early-warnings-saved-lives-jiuzhaigou-earthquake
A powerful magnitude 7 earthquake that struck China’s central Sichuan Province on 8 August 2017. A crucial factor which helped to save lives was the early warnings through broadcasting and mobile phone applications given to people well before the tremor struck.
According to Science and Technology Daily, people as far as 200 kilometres south of Jiuzhaigou, were given a 40-second warning of the impending danger, while people 95km from the epicentre in Longnan, Gansu province, received 19 vital seconds to prepare and rush to safety.
The early-warning system recognises the fast moving, but mostly harmless ‘P-waves’ created at the start of an earthquake. In its path, far more dangerous ‘S-waves’ follow.
“This technology may change the way we respond to earthquakes. It deserves to be studied closer,” says Gwendolyn Pang. “Yet early warning must go hand in hand with early action. People need to know what to do to protect themselves in times of emergencies.”
Looking ahead, the China Earthquake Administration plans to build 15,000 monitoring stations across the country by 2020, particularly in key areas such as Sichuan, Gansu and Yunnan provinces. So far, there has been about 2 billion yuan (US$300 million) invested in the early warning and quick intensity reporting program.
Reflect on the preparedness measure highlighted in the article.
1. How effective is earthquake monitoring and warning system in mitigating the impacts of earthquake?
2. How effective are the other preparedness measures such as land use regulations, emergency drills and earthquake resistant building design in mitigating the impacts of earthquakes?
LDCs lack of financial resources and technology may limit the effectiveness of developing infrastructure to mitigate the impact of earthquake as compared to the DCs. Earthquake monitoring and early warning together with emergency drills prove to be more effective as they can be used in both DCs and LDCs.
Was Nepal prepared for earthquake?
Could Nepal have done more to prepare for the predicted earthquake? Watch the video below to find out more.
Evaluate the effectiveness of earthquake preparedness measures
(revised edition TB p65 - Q6)
Infrastructure development - 101 Taipei tuned mass damper
Watch the video and see how it helped the building to resist the earthquake and prevent it from swaying too much and collapsing. A group of tourists saw how it worked when a 6.3 magnitude earthquake struck Taipei, Taiwan on 20 April 2015
managing tectonic hazards:
http://www.bbc.co.uk/schools/gcsebitesize/geography/natural_hazards/managing_hazards_rev1.shtml
Visit https://www.stopdisastersgame.org/stop_disasters/ and play the game.
Check out how you can minimise the damage from tsunamis or earthquake.
Record the strategies used to complete the mission.
Another game on disaster preparedness