Features

Will earth tremors engulf Asia’s miracle?

15 Oct 2012 - {{hitsCtrl.values.hits}}

It was learnt from the local news media that there are frequent earth tremors experienced in various parts especially in the North and South East of the country.

The incidence of these tremors has increased and the Chairman Geological Survey and Mines Bureau (GSMB) is noted to issue press statements indicating that these tremors are “minor” and there is no reason to panic. On the other hand the lead agency that is concerned with such tremors namely the Meteorology Department under the Ministry of Disaster Management is silent and I am baffled as to why these two Government Agencies are unable to issue a Joint Statement when such tremors are felt .Further a well known Professor Emeritus of Geology from the Geology Department, University of Peradeniya issues statements to the media separately analyzing these earth tremors. The present Vice Chancellor of this University, a highly experienced geoscientist, goes on record about predicting earth tremors elucidating the planetary positions and their alignments over a period of time.

As a geoscientist, I thought of educating the public on the phenomena of earth tremors and give some plausible explanations. In this paper, I hope to trace the history of earthquakes and the recent theories of re- activation of fault zones with the application of remote sensing even in stable Precambrian Shield areas such as Peninsular India.

An insight into tremors felt in Sri Lanka was brought to the notice of the relevant authorities in my article in the Features Section of the Sunday Times Plus as far back as August 5 2007. I repeated my request for a team of experts including geologists, geophysicists specially seismologists and if required oceanographers, to seriously study these tremors as it will be a serious on land if intensity of such tremors increased to over 5 in the Richter scale.

I also repeated this request in articles in the Business Section of the Daily Mirror on 2 June 2011, and 26 April 2012 (after the Tsunami scare on 11 April 2012) and my contention was that the Meteorology Department, Disaster Management Center and the GSMB should work as a team without issuing separate statement criticizing each other specially the GSMB stating that it is its prerogative to warn the public. However, I am not aware whether such a team is jointly studying the reasons for the escalation of earth tremors in the Island as I was overseas for about 3 month from July this year. However, I have learnt that the frequency of tremors is on the increase especially in close proximity to the eastern boundary of the two major rock series namely the Highland and Vijayan which runs from the north east to the south east of Sri Lanka.

If at all a serious study is under way by a team of relevant experts, the facts given below will help is fine tuning their research efforts. However being a former Director of the Geological Survey Department (present GSMB) and a retired Economic Affairs Officer of the United Nations ESCAP, no Government agency or relevant Ministry ever cared to contact me to get some guidelines about this research effort although I count over 45 years experience and it is evident that senior scientists who have dedicated most of their career in serving Sri Lanka are totally ignored by the relevant authorities.

Historical studies of earthquakes
It must be stated that extensive studies have been carried out in India on ancient earthquakes and the Island’s proximity to this sub continent will be helpful to understand the recent tremors.

Early earthquakes described in Indian mythology include extracts in the Mahabharata (1500 BC) during the Kurukhsetra battle and several religious texts such as the Buddhist Cannon mention of a Himalayan earthquake reputed to have occurred during the time of the enlightenment of the Buddha (c 538 BC) when Sri Lanka was attached to India as one landmass along the Palk Strait.

The tectonic setting of India’s collision with Asia characterized from recent seismic and geodetic studies proves relative motion of their plate boundaries. Accordingly Sri Lanka being a part of the Precambrian shield of India during this period would have experienced earthquakes of severe magnitude.

I would like to mention the pioneering studies done by A.D.N.Fernando on the change of course of the Mahaweli where the river takes an almost 90 degree turn at Minipe and now flows north south from the earlier west to east direction .

This change could be attributed to a major earthquake that triggered during pre historic times but the significance is that it falls along a reactivated structural deformity described earlier. Fernando also traced the old course of the Mahaweli from Minipe to the eastern coastline.

Past global earthquake fatalities and prognosis for next 30 years
A research study conducted by Rodger Bilham from CIRES and Department of Geological Sciences, University of Colorado, USA has indicated that by the year 2025 more than 5500 million people will live in cities in the world which is more than the entire global and rural population in 1990. It is also stated that houses for the growing urban population will be constructed in the next 30 years in regions that are known to have experienced damaging earthquakes.

The recurrence interval is predicted to be the same as the increase in population tenfold. Accordingly the tremors experienced especially in major cities in Sri Lanka should be taken seriously with the rapid urban development activities such as high rises being constructed at a rapid rate. If proper urban construction methods are not adopted there will be significant increase of fatalities taking into consideration the unprecedented increase in urban population especially in Colombo.

The author has reviewed the population and the earthquake fatality data base for the past 2000 years to identify trends in earthquake fatality rates. However the data are reliable for only the past 400 years during which time the mean annual number of fatal earthquakes has increased in proportion to population growth. Accordingly it is reported that the cumulative number of fatalities attributed to earthquakes in the past 2000 years is close to 8 million.

It has also been predicted that the annual fatality rate will rise by a factor of 4-10 in the next 30 years , attributable partly to an increase in fatality rate from moderate earthquakes near large cities , but principally from a few catastrophic earthquakes near super cities (population 2- 28 million)

Implications and occurrence in S. India
A study carried out by the University of Madras in 2005 has clearly indicated the planetary configurations in earthquake prediction. This paper identifies 6 important faults in Southern Peninsular India in Andhra Pradesh, Karnataka, Kerala, Tamil Nadu, Mahrashtra, and Orissa. Nine notable earthquakes in the above faults were recorded from 1900 to 2001 and it has been proved up to about 80 per cent accuracy that planetary force acting as kinetic energy from aligned planets Sun, Mercury and Venus and Venus and Mercury have triggered earthquakes with intensity from 5.3 to 6.0 on the Richter scale. An appendix to this study elaborated the accurate predictions in 2004 worldwide including Honshu, Solomon Islands, Gulf of California, Costa Rica, Ecuador etc. A follow up to a study initiated by the present Vice Chancellor of the Peradeniya University warrant immediate attention.

Remote sensing and active tectonics
Studies carried out by Ramaswamy in Tamil Nadu have indicated that although the Indian Peninsular has been thought to be a stable shield area the tectonic, geomorphic and hydrological anomalies observed from satellite data as well as in the field are interpreted as sinistral and dextral NW-SE dextral strike slip faults shows the area is unstable.

These anomalies and tectonic features indicate that the southern part of Peninsular India is tectonically active due to northerly and northeasterly directed compressive force related to post collision tectonics. The reactivation of some of the major faults in Sri Lanka Vis –Vis tremors should be subject to careful study.

Implications of above studies on tremors in SL
I am not aware whether accurate records are kept of the earth tremors in Sri Lanka specially the location and intensity. The information was gleaned from the local media where the recent tremors have occurred in the north east (Padiapella, Passara etc.) and some in the south east (Katuwana Mahasilava etc.) I have no access to the exact co -ordinates of these occurrences and if these are plotted accurately on the 1: 50 000 topographical maps and superimposed on the geological maps it may be revealed that these tremors fall on the major fault line separating the major rock groups (Highland and Vijayan) in the north and south east of the Island. Further it was reported that a villager in the south east found that there was steam emanating from his well just after a tremor in his area.

I am wondering whether the experts in Sri Lanka from the GSMB and other agencies who are quick is issuing press statements delved into these natural phenomena and deduced some plausible explanation .

To this end I would like to refer to a statement made by the Chairman GSMB about the earth tremors felt in Colombo, Jaffna and other parts of the country on 11 April 2012 but was unable to ascertain the cause.

However the Indian National Tsunami Warning Centre (INCOIS) Hyderabad reported a massive earthquake of 9.5 Mw which was later scaled down to 8.8 Mw.This shows the indifference of GSMB and if it had logged into Indian Tsunami Warning Centre website http://tsunami.gov.in the reasons for the tremors on this date could have been ascertained.

Conclusions
I would strongly re- iterate that the Government should take seriously the increase in the incidence of earth tremors in various parts of the country and appoint a competent team of experts to carry out an in- depth study as a tremor over 5 in the Richter scale will trigger a caterstropic and devastating earthquakes in major cities like Colombo that will have serious and unimaginable consequences with loss of life and infrastructure .If such a calamity would occur due to the lethargy of the designated agencies of the Government, the country will go back by about 20 years in its plans for rapid economic and social development and we will never be the Wonder of Asia.
(The writer is a Former Director of the Geological Survey Department- Present GSMB and Retired Economic Affairs Officer United Nations ESCAP and can be contacted at [email protected] )

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Will earth tremors engulf Asia’s miracle?

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