In the immediate aftermath of the 7.9 magnitude Gorkha Earthquake, there was a lot of talk concerning how a system—similar to the one in Japan—that gives early warnings of an approaching strong ground shaking could have saved more lives. Then, a few days ago, I read that the National Academy of Science and Technology (Nast), with the help of a Chinese institution, will adopt this system by installing 320 seismic sensors—instruments that detect seismic waves—throughout the country. While this is  a wonderful news, it would be quite premature to boast about the benefits of such an Earthquake Early Warning (EEW) system for Nepal.

Earthquake Early Warning

When an earthquake occurs, it first sends out a fast (but non-destructive) wave that is followed by a group of much slower waves. It is the latter ones that are responsible for most of the destruction and strong ground shaking. It is by detecting this fast wave that seismic sensors are able to rapidly determine the location, magnitude and size of an earthquake. This information is then used to calculate the approaching time of strong shaking for settlements that face the threat of an earthquake.This is a simple illustration of how a complicated EEW technology can alert the public of an imminent approach of a strong shaking prior to its arrival at their location. Depending on how far you are from a quake, this warning can range from a few seconds to minutes. But in a sesimically active country like Nepal, the minimum warning time can actually be less than a few seconds rather than the optimistic 10-20 seconds that newspapers reported.

In other countries, this system has proven to be vital in shutting down dangerous nuclear plants, mass transit lines and factories before they are damaged. In Nepal, it could prove useful for our major hydroelectric facilities and other integral infrastructures. But how useful can it prove for the public is a debatable question.

What safety measures can you adopt within a few seconds of warning? Let us make a thought experiment and imagine that the multi-million dollar EEW network of 320 seismic sensors was in full swing before the April 25 earthquake. As soon as the earth ruptured 15 km beneath the village of Baluwa—the epicenter of the Gorkha earthquake—it relayed the information of the incoming waves—via the internet—to the base station at Nast within seconds, which then issued a nation-wide warning (telecommunication waves travel faster than seismic waves). If we take the example of Kathmandu, then its populace would have about 22 seconds to prepare themselves for safety. (Baluwa is approximately 80 km west of the Capital, the average velocity of a strong-shaking wave is 3.5 km/sec, and let us assume that it takes one second to detect the threat and issue a warning). This, of course, is an optimistic scenario. But what if an earthquake ruptured at the fringes of the Capital? How much time would the inhabitants of Kathmandu have then? Practically, from zero to less than a few seconds. In a city riddled with narrow alleys, lack of open spaces, and poorly constructed tall buildings, will the EEW really be effective in saving lives then?

To invest or not

The early warning system can only prove to be useful if it can save lives. And this can happen only if settlements have proper quake-protection measures in place. Our misunderstanding about the benefit of the system stems from our failure to grasp what ‘Nepal is one of the most seismically active regions in the world’ actually means. This implies that an earthquake—large or small—can happen at any time and anywhere inside Nepal. So all urban and rural settlements have the potential to be the next epicenter. In such a case, it would be misleading to boast of an average warning time of 10-20 seconds. We should be outright honest—with our limited scientific knowledge—and clearly state that the minimum time for getting to safety at any location within the country will always range from zero to a few seconds. Thus, enforcing stricter quake-protection measures will have a greater potential of saving lives as compared to relying on this system.

Secondly, the cost of an EEW system is staggering; it could run into tens of millions of dollars for installation, with additional millions for yearly operation and maintainence. Thus, we need to explore the feasibility of such a system before we justify spending such a large sum of money. Wouldn’t it be wiser to invest money in promoting quake-resilient technologies instead? Thirdly, if the proposed EEW network does become operational, then it must be hooked up with the regional network of China and other adjacent countries with similar systems. Otherwise, if an earthquake were to strike outside of Nepal—and out of range from our sensors—the warning time would be hopelessly delayed.

So far, we have only heard stories of the early warning system’s success from Japan, but we have to remember that when the magnitude 9.1 earthquake struck Tohoku on March 11, 2011, their system fell short. Despite having the world’s densest network of seismic sensors and an extensive state-of-the-art EEW system, the country carelessly underestimated the possibility of the gigantic tsunami that destroyed the nuclear plant at Fukushima. Robert Geller—a professor at the University of Tokyo—said that the nuclear disaster could have been averted if Japanese had not put so much faith in a flawed system that has consistently failed to predict the risk of major earthquakes. Therefore, we should all think twice before investing millions into this advanced technology.

False sense of security

There is no guarantee that the results of the EEW system in Nepal will be any better than that in advanced nations. In fact, in a country where people believe in fortunetellers more than in doctors, we could actually lull the public by feeding them with a false sense of belief that scientists have reached a state where they can predict earthquakes. How absurd would that be? We have already witnessed failures in communicating our wisdom on earthquakes (and aftershocks) to the general public and trying to calm their fears in the past, and I fear similar confusion will arise when such a new technology is introduced in Nepal.

I think that Nast needs to rethink its decision to promote a technology in a place where its potential for saving lives is not readily apparent. It would be better if the money is spent on promoting practices and research into innovative and safe rural-housing technologies, hazard-mitigation measures, earthquake-focused urban planning system, and many other scientific and engineering endeavours that we already know can actually save more lives. We must be careful before blindly accepting a technology that has had mixed results in the past. But even if we do install such a technology, without an integrated seismic network between adjacent countries in the Himalaya  region and detailed knowledge of the subsurface geology of Nepal, the system may not save as many lives as it is intended to.

Gurung is a Doctor of Science in Geophysics and a Post-doctoral Research Fellow at Chonbuk National University, South Korea