Earthquake Warning System
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. 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.
Working of the Earthquake Warning System
The 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.
Principles that work behind the system
The less intense primary waves (P-Waves) spread out from the epicentre at first. This is followed by the dangerous secondary seismic waves (S-Waves), which cause major damage and destruction. Since the P-Waves spread out at first, based on certain characteristics it is possible to predict the intensity of the S-Waves which will follow. The early warning system precisely uses these characteristics as well as the ensuing time lag between the propagation of two waves to warn people.
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 5 km of its location.