By Arun Bapat

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The Andaman and Nicobar Island area along with neighboring Indonesia, Thailand and a number of south Asian countries have tremendously suffered due to 26 December earthquake (of magnitude around 9.3) and associated tsunami. The event could be described as most unprecedented natural hydraulic disasters. The Nicobar Island has suffered maximum as compared to the Andaman Island.

Statistically, the occurrence of tsunami is extremely rare event which could once in few decades or century. The transient event gives rise to spurt of violent and frenzied disgust resulting in some immediate populist but non-scientific and improbable suggestions. After the December 2004 Tsunami the then Chief Minister of Tamilnadu requested to provide sufficient financial aid to build a 700 km long wall in Arabian Sea opposite Tamil Coast. This was to protect the Tamilnadu coast.  The then Prime Minister immediately granted the funds. Subsequently the whole thing was forgotten by people and Government. It could be said that we sink as we rise, through sympathy.

There have been several conferences, seminars, congress, debates etc after the event. But these were mostly confined to scientific, engineering or some administrative fields. As a matter of fact some of the findings, observations and results etc should be helpful in planning future plans to avoid and suitably mitigate the tsunami disaster.

Some significant observations during pre-, co- and post-seismic event of 26 December 2004 have been used extensively in various scientific disciplines. These would definitely be useful and be used in future. The most important scientific findings are extremely useful to aviation.  About four to five weeks before the 26 December 2004 event, there was an interesting scientific observations. Australia is located at the southern corner of the southern hemisphere. All planes from Europe, India and other locations mostly pass through or over Singapore.  The long distance planes have a system known as ‘auto pilot system’ for navigation. Here the pilot gives the co-ordinates of the destination and then the auto pilot system takes over the flying of the aero plane. It was observed that all planes while passing over a particular location, the auto pilot system of the planes were getting disengaged. This means that there is something wrong (Garbar) in the system and the flying has to be taken over by manual system. During subsequent several flights the disengaging of auto pilot system was found, recorded and confirmed. At that time the scientific reason was not clear. After the occurrence, it was found that the location was the epicenter of the large earthquake. Before the occurrence of an earthquake the magnetic field at that location gets reduces. The reduction in magnetic field was affecting the auto pilot system.  Now some airlines have instructed pilots to keep a log of such events. I have tried to request the some Indian airline companies but I am awaiting their response. Now the Himalayan region is said to be heading for a very large magnitude earthquake. It would be better if airlines instruct their pilots to keep watch for such incidences.

During the tsunami it was observed that Thailand and Tamilnadu coast, especially Nagapattanam had suffered maximum damages and the tsunami heights at these locations were of the order of about 7.0 to 7.5 meters.  My self and my friend Dr Thiruvenkataswamy from Chennai mathematically examined the observation and come to very interesting observation. We have given a mathematical equation for this purpose. The tsunamigenic vulnerability of east coast of the country is not uniform. The reason is that the waves travelling in the direction of rupture have minimum energy. While the waves travelling at right angles to the direction have maximum energy. The rupture of about 1100 km during the earthquake was near Sumatera and it started from this place in SSE direction and went to NNW direction. From this location there is a Cocos Island in south direction at about 1450 km.  At the NNW end lies Kolkata and Dhaka which are more or less at the same distance of about 1450 km. At these locations the tsunami height was hardly 42 cms. This is very important from various angles.  Few years back the Bangladesh had requested an UN agency for couple of Million Dollars for organizing Tsunami protection. This is not required. Similarly the GOI should also change the uniform tsunamigenic disaster index for the entire east coast.

It well known that about ten hours before the earthquake the reception on television gets disturbed. There are audio, visual and spectral disturbances. The number of disturbances goes on increasing till earthquake time. Similarly all mobile telephone stop functioning about 100 to 120 minutes before earthquake.  These are mostly known as reliable seismic precursors.

The GOI had established an INCOIS (Indian National Committee for Ocean Information System) at Hyderabad. This does the work of observing earthquake and issue tsunami warning when required.  This is a watch and ward type organization. However, there is no institute undertaking basic studies in tsunami. Such studies would be useful to Navy, Ocean Engineering, Coastal development and Port expansion, Ocean Mining etc. I would like to request the GOI and A & N Administration to establish such an institute in Port Blair. At present there no national level institute in A & N. Most of the national institutes such as NPL, NCL etc are located on mainland. Establishment of Indian Tsunami Research Institute in Port Blair would be the first national level institute.

Dr Arun Bapat is a Research Seismologist and visited A & N after tsunami