2. INTRODUCTION
WHAT IS AN EARTHQUAKE ?
• An earthquake is what happens when two blocks of the earth suddenly slip past
one another.
• The surface where they slip is called the fault or fault plane.
• The location below the earth’s surface where the earthquake starts is called the
hypocenter.
• The location directly above the hypocenter on the surface of the earth is called the
epicenter.
• The largest, main earthquake is called the mainshocks.
• The smaller earthquakes that follow the main earthquake is called the foreshocks.
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3. • The instrument used to record the earthquake is
called seismographs.
• The recording they make is called a seismogram.
• The size of the earthquake is called its magnitude.
• Richter scale is used to assign a numerical value or to
quantify the energy released during an earthquake
(intensity).
• The scientists are not able to predict the earthquakes.
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4. STRATEGIES
Risk assessment or vulnerability analysis :-
Three main factors together determine seismic risk :
The level of seismic hazard, the number of people and amount of property
that are exposed to seismic hazards, and how vulnerable these people and
property are to the hazards.
Seismic hazards – these are sources of potential harm or loss during
earthquake.
• They can be natural phenomena, such as landslides or tsunamis.
• They can also be vulnerable buildings, brittle piping or loose equipment.
Seismic risk – these are the harm or losses that are likely to result from
exposure to seismic hazards.
Risk in our area = hazard +exposure + vulnerability. 4
5. Mitigation :-
It means how to minimize the effects of an earthquake.
Structural –
• Earthquake resistant buildings and infrastructure.
• Providing the building with strength, stiffness and inelastic deformation capacity.
• Selection of an appropriate structural configuration.
• Using earthquake shaking table to test the response of structures.
Nonstructural –
• Building codes have to be suitably formulated.
• Legal implications properly stated.
• Guidelines for earthquake-resistant construction and retrofitting.
Seismic retrofitting – it is the modification of existing structures to make them more
resistant to seismic activity, ground motion or soil failure due to earthquakes.
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6. Pre-disaster preventive measures –
Long term measures –
• Re-framing building codes, guidelines, manuals, and byelaws
and their strict implementation.
• Supporting Research and Development.
• Making all public utilities earthquake proof.
• Incorporating earthquake resistant features in all buildings at
high-risk areas.
Medium term measures –
• Retrofitting of weak structures.
• Preparation of disaster related literature.
• Networking of local NGOs. 6
7. Post-disaster preventive measures –
• Maintenance of law and order.
• Prevention of trespassing, looting etc.
• Evacuation of people.
• Recovery of dead bodies and their disposal.
• Medical care for the injured.
• Supply of food and drinking water.
• Temporary shelters like tents, metal sheds etc.
• Repairing lines of communication and information.
• Restoring transport routes. 7
8. PREPAREDNESS :-
It is a set of measures taken at the individual, organizational and societal level to minimize the
effects of an earthquake.
These measures are :–
• Securing heavy objects.
• Structural modifications.
• Storing supplies.
• Having insurance.
• An emergency kit.
• Evacuation plans.
• Educating individuals what to do during an earthquake.
• Avoiding storing items above beds or sofas.
• Planning for a related tsunami.
• Earthquake prone areas should have specific building codes.
• Proper training and drills.
• Using educational videogames.
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9. RESPONSE :-
The actions taken during and immediately after disaster impact, and are
designed to protect life and property.
The activities associated with earthquake response are –
• Early warning.
• Evacuation / migration.
• Search and rescue.
• Post-disaster assessment.
• Emergency relief.
• Logistics and supply.
• Communication and information management.
• Survivor response and coping.
• Security.
• Emergency operations management.
• Rehabilitation and reconstruction. 9
10. RECOVERY :-
Recovery activities consist of actions taken to return to (or, ideally, exceed) pre-
earthquake levels of activity and productivity.
These activities include –
• Reconstruct and restore the earthquake-stricken area.
• Deal with the disruption that the disaster has caused.
• Mitigate future hazards.
• Planning for “business continuation.”
• Rebuilding.
• Provide accurate and timely information.
• Identify suitable, earthquake resistant short- and long- term shelters.
• Promote funding and training of post-earthquake building inspection volunteers.
• Enhance ability to provide crisis counseling to individuals in affected areas.
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