Inaugurating the only functional regional earthquake early warning (EEW) system of the nation together with Uttarakhand Bhookamp Alert, a mobile application for accessing the earthquake warnings and other earthquake risk reduction related information, at Uttarakhand Secretariat in Dehradun in the forenoon of August 4, 2021, the Chief Minister Pushkar Singh Dhami reiterated the resolve of the state government to make Uttarakhand resilient to disaster incidences. He at the same time promised unconditional support of the state government for experimenting with innovative ideas and technologies for reducing the impact of disaster incidences in the state. He called upon scientists and disaster risk reduction professionals to ensure adequate early warning of other disasters including flash flood events and rule out possibility of the recurrence of Dhauliganga disaster like situations. Reviewing the possibilities of the EEW system he called upon officials to explore possibility of collaborating with the neighbouring states and making these warnings available to people in those states as well.
On this occasion the Minister, Disaster Management Dhan Singh Rawat said that the government is taking all measures possible for averting disaster induced losses, and collaborating with various academic, scientific research and technical institutions for the use of state of art technological solutions not only for monitoring and early warning of various hazards, but also for prompt and effective post-disaster response. He added that the state government has already sanctioned a long term project for the monitoring of remote glacial lakes so as to ensure adequake warning of flash flood incidences, particularly in the higher reaches of the province.
Prof. Kamal of Indian Institute of Technology (IIT) Roorkee explained the technical integrates of both, the EEW system and mobile application for accessing the warnings through a brief powerpoint presentation while those of IIT associated with this initiative including Prof. Ashok Mathur, Prof. Ajay Gairola, Prof. M.L. Sharma, and Dr. Bhanu Chamoli joined the event online.
Besides the Chief Secretary Dr. S.S. Sandhu and Additional Chief Secretary Anand Vardhan those present in the inaugural ceremony included Secretary, Disaster Management S.A. Murugesan, Additional Secretary, Disaster Management Dr. Anand Srivastava, Executive Director, Uttarakhand State Disaster Management Authority (USDMA) Dr. Piyoosh Rautela, and Junior Executive, USDMA Rahul Jugran.
As explained by Prof. Kamal the EEW system being operated in Uttarakhand comprises of 200 seismic sensors installed largely along the Main Central Thrust (MCT) zone across the state that is seismically highly active, and considered by scientific community as being the possible source of future devastating seismic tremor. These sensors relay the recorded signals on real time basis to the control unit at IIT Roorkee where based on an algorithm developed specifically for this purpose, these signals are analysed, and accordingly warning is generated and disseminated if the magnitude of the earthquake is assessed to be more than the predefined threshold; 5.5 on Richter Scale in the present case.
Though designated an EEW system, according to Dr. Piyoosh Rautela the system does not provide an earthquake warning as it works on the waves generated in an earthquake. In simple words it can be said that the system starts analysis, and processing only after an earthquake has taken place. This system actually provides the warning of the seismic waves that could cause violent ground motion resulting in damage to structures.
According to Prof. Kamal this system is to provide warning lead time varying from a few seconds to a minute depending on the distance from the epicentre. S.A. Murugesan added that the state government is installing sirens at various places for alerting the public, particularly in urban areas with high population density. He added that the warning can also be accessed by anyone over a mobile phone using a dedicated application, Uttarakhand Bhookamp Alert, that is available for download at Google Play Store for Android phones and Apple App Store for i-phones. Using this application one can also send messages to the rescue workers, if trapped during an earthquake. The rescue workers can at the same time determine the location of the trapped persons, if they are using this application. S.A. Murugesan added that the use of this application would enhance the chances of being located, and saved after an earthquake.
It however needs to be understood that earthquakes cannot be forecasted or predicted, and this system does not attempt to do so. The system however detects the waves generated in an earthquake, assesses the earthquake magnitude, and relays the warning if the magnitude is more than a predetermined threshold. According to Dr. Piyoosh Rautela efficacy of this system has been validated over a period of more than 03 years, and USDMA is providing the financial resources required for keeping this system operational while routine technical aspects are being managed by IIT Roorkee.
The earthquake threat
As communicated by Dr. Piyoosh Rautela Uttarakhand Himalaya faces high risk of being hit by a devastating earthquake in near future. Despite having witnessed the devastation caused by Mw 6.8 October 20, 1991 Uttarkashi and Mw 6.4 March 29, 1999 Chamoli earthquakes, there has been no large magnitude earthquake (Mw > 8.0) in the region during the previous more than 215 years, or since Mw~7.5 September 1, 1803 Garhwal Earthquake that caused damage as far as Delhi, Mathura, Aligarh, and Lucknow. Moreover the province is located in the seismic gap of Mw~7.8 April 4, 1905 Kangara and Mw~8.2 January 15, 1934 Bihar–Nepal earthquakes. This simply imples that the strain accumulated in the region due to continuing north-northeastward movement of the Indian Plate has not been released for a long time. The province therefore faces high seismic hazard, and is often cited by Earth Scientists as being a potential candidate for hosting a major tremor in near future.
Earthquake is therefore a cause of serious concern for the state as it could roll back the economy and pace of development by several years in a single jolt lasting no more than a few seconds. Loss of infrastructure, property and assets apart, the earthquake is likely to cause massive loss of human lives which is the major concern. Saving human lives is always the first and foremost objective of all disaster risk reduction interventions, and a reliable and accurate warning system promises to save lives.
The earthquake waves
As we know, an earthquake is caused by the release of strain accumulated over long periods due to the movement of tectonic plates; the Indian Plate continuously moves north-northeastward at 5 cm/year against the Eurasian Plate. The location below the surface where this energy is released by the disruption, and displacement of rock mass causing an earthquake is called focus or hypocentre of the earthquake, and from there the released energy propagates in all the directions in the form of waves causing vibration, ground motion, and destruction. Epicentre with which we all are more familiar, is located vertically over the hypocentre on the surface of the earth.
P-wave or Primary wave travels faster (~5.55 km/sec), and propagates through solid rock and fluids. Subject to a P-wave, particles move in the direction of wave propagation. Sometimes animals can hear the P-waves of an earthquake. Dogs, for instance, commonly begin barking hysterically just before an earthquake hits or more specifically, before the surface waves arrive. Usually people can only feel the bump and rattle of these waves. S-wave or Secondary wave has lower velocity (~3,25 km/s) and can travel only through solid medium. Subject to a S-wave, particles move perpendicular to the direction of wave propagation.
Surface waves travel along the surface of the earth at speeds slower than body waves (< 3.0 km/s), and comprise of Love and Rayleigh waves. It is surface waves that are almost entirely responsible for the damage and destruction associated with an earthquake.
The warning lead time
As put forth by Dr. Piyoosh Rautela, the difference in speed and devastating potential of seismic waves is the key to generating the warning. P-waves travel faster but are not damaging while the S- and surface waves (Love and Rayleigh waves) that travel slow cause most devastation. P-waves therefore reach a place before the damage causing S- and surface waves, and this time lag increases with increasing distance from the source.
Dr. Piyoosh Rautela added that based on where the P-waves are intercepted for generating the warning there are two types of EEW systems; onsite and regional. In onsite EEW system the earthquake sensors are installed at the place for which warning is to be generated, while in regional EEW system sensors are installed near the probable source of the earthquake, and from there the detected signals are transmitted using electromagnetic waves that travel at the speed of light, i.e. 3,00,000 km/s.
Dr. Piyoosh Rautela explained that if the warning is to be generated for a place some 150 km away from the source of an earthquake, P- and S- waves travelling at an average speed of 5.55 and 3.25 km/s respectively, would take 27.0 and 46.2 seconds respectively to reach the designated place.
Considering the processing time to be negligible as it takes place using electrical impulses that travel at the speed of light, the onsite sensor would sound an alarm 27.0 seconds after the earthquake when P-waves reach it after travelling a distance of 150 km. This would provide a warning lead time of 19.1 seconds as the damage causing S- and surface waves would take 46.2 seconds in covering this distance.
What if we have an array of sensors in the proximity of the source, and from there the signals are transmitted at the speed of light?
In such a situation the earthquake waves would be detected instantaneously, and relayed at the speed of light to generate a warning. We would thus have a warning lead time of approximately 46.2 seconds.
This is not at all that simple but then, which one would you prefer when you clearly know that every second counts when it comes to saving human lives?
EEW system with warning lead time of 19.1 seconds or 46.2 seconds?
It needs to be realised that there would be no warning for areas in close proximity of the earthquake epicentre even theoretically; that is going to remain a shadow zone which is a technological limitation. Moreover, we are preparing for a future earthquake that is likely to be housed in Uttarakhand Himalaya. So, being located in the proximity of the earthquake epicentre warning lead time for most areas in Uttarakhand would be fairly small.
Most population of the province is however concentrated towards the southern and western fringe in the foothills and plains, and these places are at at a considerable distance from the likely source of earthquake. The people in these areas; Dehradun, Haridwar, Kashipur, Kotdwar, Ramnagar, Haldwani and Kathgodam would therefore be getting fairly good warning lead time, at least for minimising casualties. S.A. Murugesan added that the state government clearly realises this, and has accordingly started putting up sirens for warning the public in these areas.
As the warning lead time incrases with distance from the epicentre, according to Dr. Piyoosh Rautela this EEW system could be extremely useful for western Uttar Pradesh, and the National Capital Region (NCR) that are densely populated, and have concentration of high value, and strategically important infrastructure and assets of various sort. Mw 7.5 September 1, 1803 Garhwal Earthquake as also recent Mw 7.6 January 26, 2001 Bhuj Earthquake clearly show that massive losses can be inflicted in areas that are at long distances from the earthquake source. Moreover many geoscientists have expressed possibility of major devastation in the densely populated Indo-Gangetic plains due to a high magnitude earthquake in the Himalayas.
Realising the threat posed by earthquakes in the Himalayan region many installations in the NCR have already started installing onsite EEW systems. We however know that these have the capability of providing relatively short warning lead time. In a scenario where every second added to the warning lead time is to translate into saved human lives and assets, the governments, institutions and installations in this highly vulnerable region need to piggy back this functional EEW system of Uttarakhand government. This could be realised with little or no additional cost with dividends likely to far surpass anyone’s imagination.
Having put in place an EEW system is no doubt an accomplishment worth a loud applause. This however does not imply that the people in Uttarakhand have been shielded from seismic risk, and there remains no cause of concern. Warning system or no warning system, the earthquake is to tear down our infrastructure and buildings, if these are not earthquake resilient, and therefore we need to ensure that elements of earthquake safety are incorporated in all our structures.
Illusion of both government and public apart, even the way forward to saving lives during an earthquake using this warning system is not going to be that simple and straight forward.
(i) The sensors: Immense effort would be required to ensure that the earthquake sensors installed in remote areas remain operational, and connected to internet at all times. Previous experience suggests that 10-15% sensors do not operate at any given time due to various reasons. Given the constraints of access, power supply, power back up and internet connectivity this is not going to be easy.
(ii) The sirens: Likewise expanding the array of warning dissemination infrastructure, and keeping the sirens operational and connected to internet at all times would require effort, energy and resources. Experience suggests that a large number of computers connected to the warning dissemination infrastructure are routinely shut down at the end of the day. Curbing this practice would not be easy and would require awareness that shutting these could jeopardise safety of people.
(iii) The mobile application: It needs to be realised that developing an application is just the tip of an iceberg. Real challenge lies in making people download and install Uttarakhand Bhookamp Alert on their mobile phones, and the success of the system should only be assessed from the download count of the application. No one should be under an illusion that the application would become popular just because it provides certain services and perceived safety. It is a proven fact that people do not always subscribe to or buy what is the best or safest. Diffusion of innovation is an altogether different ball game in which government agencies have often failed miserably. This would therefore require persuasion, motivation and incentivisation together with involvement of a dedicated team of social science, psychology and marketing experts. To begin with the state government could issue an appeal for its employees to download the application and bring forth awareness on its utility amongst their acquaintances.
(iv) Confidence of the masses: Convincing people that earthquake warning is possible, and 10-20 seconds are good enough for saving lives would not be easy. People would certainly not buy the idea unless they are convinced that they can actually get to safety in 10-20 seconds. Practical and simulated demonstrations, with capability of audience engagement would have to be designed, crafted and disseminated for ensuring this.
(v) Dos and Don’ts: If not bigger a comparable challenge would be to make people aware of what they should do after they hear the sirens blowing. Warning is really meaningless unless it is followed by planned and coordinated actions for saving life and property. Right action should not be expected from panic-stricken people unless the dos and don’ts are incorporated into their muscle memory through repeated and continuous practice. Despite everything going by the plan this could otherwise prove out to be a weak link and spoil the entire show. Sustained, dedicated and sincere efforts would be required for ensuring this.
(vi) False alarms and missed events: Lastly, to maintain the faith of the masses on the efficacy of this system, possibility of false alarms and missed earthquakes would have to be minimised to the extent possible. They should invariably hear the warning beep of their mobile phones before they feel the next earthquake. This is required to be ensured even if it amounts to lowering the warning threshold. People really have no time to confirm the earthquake magnitude, and listen to the explanations for missed alarms. Remember, it is not going to work if it does not sound reliable to the masses, and gaining trust takes time during which success has to be necessarily demonstrated.
Every system however has an incubation period during which technology, processes and protocols are tested, verified, improved and improvised. The efforts put in by the state, and the enthusiasm and dedication of the officials suggest that this system is to pave way for bringing forth seismic resilience, not only in Uttarakhand but also in the surrounding densely populated areas of Uttar Pradesh and National Capital Region that should soon choose to have the safety cover of this system.
In the end it needs to be remembered that disasters do not adhere to political boundaries and September 1, 1803 Garhwal Earthquake caused damages in Delhi, Mathura, Aligarh and Lucknow. Likewise April 4, 1905 Kangara Earthquake caused damages in Dehradun – Mussoorie area, October 8, 2005 Muzaffarabad Earthquake caused damages in Jammu and Kashmir while April 25 and May 12, 2015 Gorkha and Dolakha earthquakes caused damages in neighbouring areas of Uttar Pradesh.
The sensors installed by Uttarakhand are located in the MCT zone falling in the province. The state could however be hit by an earthquake housed in western Nepal or eastern Himachal Pradesh for which there would be no warning. In view of this National Disaster Management Authority (NDMA) is planning an integrated earthquake early warning system for the entire Himalayan region under National Seismic Risk Mitigation Programme that is to be implemented between 2022 and 2025. Rather than starting afresh it would be advised that the experiences of Uttarakhand EEW system be integrated into the planned system so as to make in more robust.