Predict, protect, prepare Objectives : To understand the need to predict, protect and prepare NT pg 30/31
Look at the picture carefully… what is happening here? Why is this being done?
http://uk.youtube.com/watch?v=3Rw0ayg85NM&feature=related http://uk.youtube.com/watch?v=lI1M8o0BHPc The photo shows how building designs are tested to see how they would stand up in earthquakes to help protect the occupants . The following clip shows an earthquake drill in California – it is called The Big Shakeout and is one way that people can prepare for an earthquake.
Predict, protect, prepare
Prediction – trying to forecast when an earthquake will happen
Protection – constructing buildings so that they are safe, to an appropriate standard and using designs to withstand movement
Preparation – organising drills and codes of practise so that people know what to do in case of emergency e.g. hospitals, emergency services and inhabitants practising for major disasters
How can scientists predict?
Putting laser beams across a fault to detect any small movement
Monitoring release of any radon gas
Monitoring water levels
Using seismometers – instruments that measure the movement of the ground
Graphing magnitude of earthquakes in specific places from the past
Watching for strange animal behaviour
Reducing the Effects of an Earthquake - protect
There are a number of strategies that can be used to reduce the impact of earthquakes. They all involve being fully prepared for the impact. 1. Install adequate warning systems. Warnings of the onset of earthquakes can be detected by organisations and governments. This involves the use of special sensing equipment. However, this alone will not be of much use without effective communication systems in place. Warning systems should be linked to government agencies, rescue and emergency services, and of course to the public.
2. Have a unified plan of action
Time is of the essence in the case of major disasters. Delay in support/action can result in further deaths. Local, national and international support services should know exactly what to do, and how they work together to produce a rapid, efficient and effective support system. 3. Provide information before the earthquake strikes This can involve the use of radio, TV and newspapers. Everyone should know (i) What precautions they need to take for the own safety and for the safety of others. (ii) How to secure their home and belongings against damage (iii) What to do during an earthquake .
4. Provide rapid and efficient support services after an earthquake Apart from medical assistance, people need food , water and accommodation .
Delays in bringing rescue services to the affected areas of population can result in people dying when they have been trapped in buildings.
Manual movement of large amounts of rubble can prove virtually impossible to achieve in a few hours, for large areas of destruction.
Therefore, heavy duty machinery is needed to reduce the time taken for rescues to be achieved .
Protect - Earthquake-Proof Buildings
A building can never be made totally earthquake-proof. However, there are a number of ways that existing buildings can be made more resistant to earthquake damage.
New buildings can be designed to have a number of structural features which are more likely to provide resistance to the damaging effects of earthquakes. Structural damage could still occur, but the safety of the people inside the buildings is greatly enhanced by these special features.
Many of the injuries sustained by people are as a result of falling debris from buildings e.g. broken glass. Special attention to these potential hazards is a priority when designing earthquake-resistant buildings.
(i) Base isolation This works by essentially separating the building from the moving ground during an earthquake. The base will move with the ground, but the movement to the rest of the building is minimised by the provision of special features such as Teflon pads, enormous rollers, coiled springs
(ii) Diagonal bracing Shearing forces as distinct to push and pull forces, can cause tremendous damage to buildings. Diagonal bracing helps to minimise the effect of these shearing forces during an earthquake. (iii) Passive damping . Passive damping involves using a range of techniques. The main objective is to absorb the energy without allowing it to impact on the main structure of the building. Certain methods use materials which will deform easily, and therefore absorb the energy, without breaking. Other techniques include the use of large masses which are made to move out of phase with the movement caused by the earthquake. This tends to cancel out the disturbance, just like a trough of a wave in water meeting a crest of a wave will result in calm water (destructive interference in waves) ...
Computer controlled movable roof weights to counter the shock waves
Steel frames that can sway during earth movements. Building needs to be stiff vertically but flexible horizontally
‘ Birdcage’ interlocking steel frame , cross bracing to give added strength and prevent twisting
Automatic window shutters to prevent falling glass
Sheer core of reinforced concrete and tensioned cables around lift shaft
Fire resistant building materials
Outer panels flexibly attached to steel structure
Automatic sprinkler system and gas shut off to prevent fires
Strengthened steel and reinforced concrete road supports
Foundations set deep into the ground
Rubber shock absorbers to absorb earth tremors, foundation piles made out of alternative layers of steel and rubber to make building flexible
Base isolator allows sideways motion
Open areas where people can assemble if evacuated
Describe 4 ways in which buildings can be made to withstand an earthquake
Earthquake resistant house in LEDC
Hollow concrete bricks designed to cause less damage if they fall
Roof made from reinforced concrete
Foundations made of stone largely from the remains of destroyed houses
Reinforced steel pillars provide strength and flexibility
Earthquake proofing is expensive. In developing countries the use of appropriate technology can protect people.
Bamboo houses – bamboo is strong, yet bends easily and has been proven to withstand earthquakes
In Costa Rica 70ha of bamboo plantation will build 1,000 houses
A tiny proportion of the energy needed to make steel is needed to process the bamboo
Costa Rica earthquake 2009 proved the effectiveness of this building material
What appropriate and sustainable methods can developing countries use to protect buildings from earthquake devastation .
People need to know what to do before, during and after an earthquake
Earthquake drills in schools
Japan ‘Disaster Prevention Day’ held annually on 1st Sept
Earthquake shaking maps can help with planning and responding to emergencies and targeting aid. Computer generated scenarios show the intensity of ground shaking at different locations
People can be made aware of the risk level where they live.
Local authorities can put in appropriate levels of protection
1.Why do many people continue to live in cities which are at risk from earthquakes?
2.Why have scientists and engineers concentrated on earthquake protection rather than prediction ?
3.Describe the ways that people can prepare for a major earthquake
4. Give 2 ways in which earthquake shaking maps can benefit people
Design a poster to promote earthquake preparedness
Suggest 10 items that should be included in an earthquake kit