Creating seismic awareness
BY Agencies9 Feb 2017 3:29 PM GMT
Agencies9 Feb 2017 3:29 PM GMT
A moderate 5.8 magnitude earthquake hit Uttarakhand on the night of February 6. As usual, there was the news rush -- breaking news, specialists' comments and the like. But the earthquake news was somewhat eclipsed by the charged election environment.
An earthquake's effects are all-pervasive, and every sector needs to account for it. Earthquake mitigation efforts during the post-seismic period require large amounts of financial aid. However, in most of the states, the disaster management offices are typically headed by the Revenue Secretary.
India has two types of disaster management agencies. There is the National Disaster Management Authority (NDMA) and, at the state level, the State Disaster Management Authority (SDMA). The state agencies follow the directives, instructions, and rules of the NDMA. Some of the praise-worthy work by NDMA is rescue and evacuation in Japan after the Fukushima earthquake and tsunami of March 2011. Similar were the efforts after December 26, 2004, earthquake and tsunami in the Indian Ocean, and after the torrential downpour in Chennai in December 2015.
Most of the mitigation efforts are for the post-seismic (or post-disaster) period. The principal aim has been focused on engineering retrofitting and
strengthening of weak structures. This involves some action that may be difficult to implement due to administrative and financial reasons.
For retrofitting a house, the funds required are a big problem. Very few owners are ready to invest an additional amount of about five per cent of
the total cost to ensure seismic safety in new constructions. Similar is the case of re-strengthening. Moreover, these are long-term efforts, and so
the significance is not immediately realised by the common man.
As far as seismic disaster mitigation and management are concerned, there are no time-bound or mission-bound programmes or accountability for disaster relief. It is necessary for disaster administration to remain away from palliative solutions. These are of no use. The disaster after the cloudburst at Badrinath in Uttarakhand in June 2013 had clearly shown the massive damage to constructions in river beds. But still, this continues.
It is, therefore, necessary to find an alternative which could give a reliable indication of an incoming earthquake in sufficient time so that the
administration could gear up the entire mitigating machinery for action. It is a fact that till now, no scientist has come out with a mechanism whereby the location, magnitude and time of earthquake could be predicted.
There is, however, a silver lining. The seismo-electromagnetic effect (SME Effect) definitely provides a viable solution. It changes the post-
seismic mitigation approach to pre-seismic mitigation. With the help of the SME, it is possible to predict the occurrence of a destructive
earthquake up to 10 hours in advance.
How does this work? Before an earthquake occurs, the temperature at the hypocenter (the underground point below the epicentre) rises. This reduces the earth's magnetic field and adversely affects electromagnetic communication.
About 10 hours before an earthquake, the reception on television sets witness audio, visual, and spectral disturbances. The frequency of
disturbances goes on increasing till the quake strikes.This was observed and noted for the first time by several people in Maharashtra before the 1993 Latur earthquake. It was observed in Bhuj before the destructive quake of January 26, 2001.
This "minus ten hours before" precursor is followed by another extremely reliable one. It appears about 100 minutes before a quake. All mobile telephones in the entire epicentral area get disrupted. Landlines continue to function, but the audibility is affected and is accompanied by noise.Thus, if it is found that the functioning of mobile telephones is affected in an extensive area of 30 to 70 km radius or more, it could be assumed that an earthquake would occur within the next 100 minutes or so.
I have spoken about these precursors during lectures across the country. I was happy to see the effect of this mass education. After the 6.8
magnitude India-Myanmar border quake of April 10, 2016, I was informed by emails and landline telephones from Aizawl, Dimapur, Dibrugarh, and Guwahati that mobile telephones were not functioning. Similarly, I was also told by a friend from Kathmandu about mobile communications failure before the April 25, 2015, earthquake of 7.5 magnitude.
SDMAs have used a one-page information pamphlet I prepared about reliable short-term seismic precursors in Assam, Himachal Pradesh, Uttarakhand, Mizoram, and Bihar. Also, the pamphlet has been found to be useful in countries such as Nepal, Myanmar, Indonesia, the Philippines, China, Japan, Mongolia, Iran, Ethiopia, Turkey, Chile, and Peru.
It is essential to create seismic awareness among the common people of seismically active states. In addition to preparedness, mitigation and prevention, it is also essential to educate the people about reliable short-term seismic precursors. The palliative solutions, monetary compensation and piecemeal solutions may be reduced as these have limited value and at times could be wasteful.
(Arun Bapat is a research seismologist from Pune and a former head of earthquake engineering research at the Central Water and Power Research Station. Views expressed are strictly personal.)
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