The outermost crust of earth is made of tectonic plates, with edges marked by faults. These plates are in constant motion. An earthquake occurs along the fault lines of these plates, when they slide past each other or collide. The location on the tectonic plates where the collision occurs is the hypocentre, while the surface area of earth directly above the hypocentre is the epicentre of the earthquake. Earthquake results in violent shaking of the ground, and leads to collapsing buildings and bridges. Sometimes the magnitude is large enough to trigger even landslides, avalanches, and tsunamis.
Can Earthquakes be Predicted?
In spite of great advancement in science and technology, earthquake is one natural disaster which cannot be predicted. The probability of a future earthquake can be calculated based on scientific data, but it spans over a very long period of time; for eg, scientists have predicted a 38% chance of a major earthquake in southern California at any time in the next 30 years. Scientists require precursors for a reliable prediction. Precursors are a kind of a signal in the activities of earth that point towards an impending earthquake. However, seismologists have failed to find any such precursors where earthquakes are concerned.
Seismic Zones or Earthquake Prone Areas
It is true that scientists have not been able to find a way to predict when an earthquake is going to happen. But they have a pretty good idea as to where it will happen. The entire world is divided into five seismic zones on the basis of intensity of earthquakes and vulnerability. India falls within the 10 most earthquake vulnerable countries in the world. It goes without saying that earthquake brings along with it mass death and destruction. The recent earthquake in Nepal has served as a reminder that they can happen anytime. So, in a case where predictions are not possible, we can arm ourselves by being aware of the most vulnerable places in India for an earthquake, and by being prepared for it.
The 10 most Vulnerable Cities
According to a seismic zoning map issued by the Bureau of Indian Standards and quoted in the National Disaster Management (NDM) report, the Indian cities that are considered to be high earthquake prone zones are:
1. Guwahati: Belongs to Zone V – very severe intensity zone.
2. Srinagar: Belongs to Zone V – very severe intensity zone
3. Delhi: Belongs to Zone IV – a severe intensity zone.
4. Jamnagar: Belongs to Zone IV – a severe intensity zone.
5. Patna: Belongs to Zone IV – a severe intensity zone
6. Meerut: Belongs to Zone IV – a severe intensity zone
7. Jammu: Belongs to Zone IV – a severe intensity zone
8. Amritsar: Belongs to Zone IV- a severe intensity zone
9. Jalandhar: Belongs to Zone IV – a severe intensity zone
10. Dehradun: Belongs to Zone IV – a severe intensity zone There are 30 more Indian cities which fall under Zone III which is a moderate intensity zone.
Preparedness for an Earthquake
An earthquake strikes suddenly, without any warning, and can happen at any time of the year. We do not have any control over this natural calamity. The following are a few safety tips on planning, preparing, and practicing what you and your family will do for surviving an earthquake: For Individuals • Ascertain the risk of earthquake in the area that you are living in. It is important to be aware.
• Learn about the earthquake evacuation plans of the building you live in, and also any other building (like offices and schools) that you frequent.
• Mark a second exit from each room for emergency evacuation, and in case not possible, keep a rope or ladder handy. • Mark a safe place within the house, in case exit is not possible.
• Keep emergency food, water, first aid kits, and fire extinguishers ready at hand and marked well. • Mark the utility switches or valves, like the main power switch, so that they can be turned off.
• Mark an emergency outdoor safe location where the whole family is to meet in case you are separated.
• Keep a priority list of things to be taken out with you if possible. Your wallet with all the emergency and bank account numbers should be one of them.
• Keep important documents like wills, insurance policies, ownership certificates, birth certificates etc in a fire proof safe which can be retrieved after the calamity is over.
• Practice drills of drop, cover and hold on with the entire family.
• Please keep the children of the house in full picture so that they know what is to be done in case of an earthquake.
• Be prepared for aftershocks. Some earthquakes may just be a foreshock for an even bigger one to come. Be prepared.
• Moving of the ground is seldom the reason for death and injury during an earthquake. More destruction occurs because of the after effects like fire, flying glass, and falling objects. Work together as a community and work out hazard plans.
For the Government
• The government should take adequate precautions while building cities. Mushrooming of concrete structures in earthquake prone zones is very dangerous. Gurgaon, lying in Zone IV seismic zone which is a severe intensity zone, is one such example. One tremor like the one in 2001 in Bhuj will turn this urban city into rubble.
• Hilly regions should desist from building concrete structures. The age old tradition of building wooden and bamboo houses will see lesser destruction in case of an earthquake.
• The Government should regulate and enforce building and other safety codes. • A comprehensive disaster management plan should be ready at district, state and national levels.
• All public health services should have a disaster management plan, with easily accessible medical supplies, ambulances, etc., with an option to increase the capacity if required. The effect of the damages caused due to an earthquake is multiplied manifold in India because of lack of preparedness and awareness among the civilians. So to minimise the destruction, be aware. Be safe.