Q+A: Early Earthquake Warning System at NCR

The National Capital Region’s first Early Earthquake Warning System procured by the Haryana government at the cost of about Rs 38 lakhs has been installed recently at the Haryana Institute of Public Administration (HIPA) building in Gurgaon. According to the government sources, the early warning system has been housed in the HIPA’s Centre for Disaster Management to warn staff members and raise awareness among the visiting officials, industrialists, private developers and companies about the benefits and salient features of the technology.

Salient features

The Early Earthquake Warning System is capable of issuing a warning 30 seconds before the occurrence of a strong earthquake. It is also capable of turning off the water and energy systems like electricity and gas supply systems thereby minimizing the loss of life.

Why the NCR needs such a system?

Gurgaon and Delhi falls under the Seismic Zone IV. So, there is a chance for high intensity earthquakes to strike these areas. With the region having more than 1,000 highrisers which houses and employs a large chunk of population, it is imperative for the government to install such early warning systems as even a 30 second time may be crucial to save lives before a major quake.

How does the early earthquake warning systems functions?

The early warning system has been installed on the foundation pillars of the building. A selected threshold level of intensity has been set to make the alarm active if it crosses that particular threshold level. The system is mainly comprised of two components – master and submaster. The submaster detects earthquakes and is connected with data lines to the master. The master device cyclically scans the submaster to decide whether or not to trigger the alarm. When the predicted intensity of secondary waves crosses the set threshold, the alarm is triggered. It also activates the Energy Management System (EMS) which parks the elevators, opens the safety doors and gates, switches off the connected gas, electricity and water supply systems and stops the working of sensitive machines.

What is the main principle behind the working of the early earthquake warning systems?

The less intense primary waves spreads out from the epicentre at first. This is followed by the dangerous secondary seismic waves, which causes major damage and destruction. Since the primary waves spreads out at first, based on certain characteristics it is possible to predict the intensity of the secondary waves which will follow the primary waves. The early warning system precisely uses these characteristics as well as the ensuing time lag between the propagation of two waves to warn people.

What are the specific features of the early warning system installed in Gurgaon?

For the system installed in HIPA, the threshold intensity value has been set at 5 on the Richter scale. The system is yet to have an outdoor public alarm to warn people within 5km of its location.

Where else the early earthquake warning system is in use?

The system is being in use in some 25 countries like USA, Germany, Chile, Pakistan, China, Mexico etc. the system was originally developed by Secty Electronics GmbH, a German company specialising in earthquake science, in collaboration with GFZ, the German Research Centre for Geosciences.

What is an earthquake? What are the types of earthquakes?

In Earthquake, there is a sudden release of energy in the Earth’s crust, which leads to a series of motions because of the waves created due to this energy (called seismic waves) released. These seismic waves originate in a limited region and spread in all directions. There are several types of Earthquakes such as:

• Tectonic Earthquakes: Tectonic Earthquakes are most common and generated due to folding, faulting plate movement.
• Volcanic Earthquakes: Earthquake associated with volcanic activity are called volcanic earthquake. These are confined to areas of volcanoes and pacific ring of fire is best example of these types of earthquakes.
• Collapse Earthquakes: They are evident in the areas of intense mining activity, sometimes as the roofs of underground mines collapse causing minor tremors. Explosion earthquakes: This is a minor shock due to the explosion of the nuclear devices.
• Reservoir Induced Earthquakes: Large reservoirs may induce the seismic activity because of large mass of the water. They are called reservoir induced earthquakes.

How seismic zoning in India is being done?

Indian subcontinent has a long history of devastating earthquakes, partially due to the fact that India is driving into Asia at a rate of approximately 47 mm/year. More than 50% area of Indian Subcontinent is vulnerable to earthquakes. According to the IS 1893:2002 (It is the latest code of Bureau of Indian Standards (BIS) which lays down the criteria of for earthquake resistant design of structures), India has been divided into four seismic zones viz. Zone-II, -III, -IV and -V unlike its previous version which consisted of five zones for the country. After some revisions in the previous zoning, Zone I was altogether removed. This zoning has been done on the basis of MSK-64 scale and a IS code Zone factor has been assigned by the BIS to each of them. The zone factor of 0.36 is indicative of effective (zero period) peak horizontal ground acceleration of 0.36 g (36% of gravity) that may be generated during MCE level earthquake in this zone. They are presented in the following table with IS code.

What are the Critical areas of concern for the management of Earthquake in India?

In India Today, majority of the buildings constructed in India, especially in suburban and rural areas, are non-engineered and built without adhering to earthquake-resistant construction principles. Most contractors and masons engaged in the construction of these buildings are also not familiar with the earthquake-resistant features specified in the building codes. The critical areas of concern for the management of earthquakes in India include the:

• Lack of awareness among various stakeholders about the seismic risk;
• Inadequate attention to structural mitigation measures in the engineering education syllabus;
• Inadequate monitoring and enforcement of earthquake-resistant building codes and town planning, bye-laws;
• Absence of systems of licensing of engineers and masons;
• Absence of earthquake-resistant features in non-engineered construction in suburban and rural areas;
• Lack of formal training among professionals in earthquake-resistant construction practices; and
• Lack of adequate preparedness and response capacity among various stakeholder groups.