How well do we know our ocean?

Published: Monday 31 January 2005


imageThe Indian ocean covers 73,556,000 sq km, or 20 per cent of the world’s surface. Aspects like oceanography, geo¬physical phenomena, undersea exploration and eco¬nomic and military uses have a bearing on ocean behaviour. How cognisant are our experts with this large water body?

Other than isolated research programmes associated with the Indian monsoon system — the Bay of Bengal Monsoon Experiment (1999-2000) and Arabian Sea Monsoon Experiment (2002-2003) — the funds allocated for oceano¬graphic research (Rs 147 crore in 2003-2004), have spent, till recently, on the Antarctica programme or undersea explo¬ration for strategic metals and medicines.

Disaster preparation is confined to cyclone warning sys¬tems. Cyclones in Indian waters are tracked using INSAT satel¬lites, cyclone detection radars (range: 400 km), installed at 10 stations including Paradip, Vishakhapatnam and Bhuj. Experts now claim that the new upgraded cyclone surveillance systems can detect any cyclone in the region.

Tsunamis new to Indian Ocean?

Notwithstanding the establishment’s defence that tsunami are a rare phenomenon for us, the Indian Ocean has experienced tsunami, although not on the scale (four to five tsunamis each year) and experience of countries along the Pacific Ocean. While Harsh Gupta, secretary, Department of Ocean Development (DoD), says the last recorded tsunami occurred in 1881, the NIO called it the fourth tsunami to hit the Indian shorelines since 1881. Some of the confusion is due to lack of proper documentation. Dale Dominey-Howes of the department of physical geology at Macquarie University in Australia, told Down To Earth, “We only have limited data on tsunami events in the Indian Ocean. There is a possibility that there may be unrecorded tsunami that has occurred in the Indian Ocean.” G S Roonwal, geologist in Delhi University agrees, “Studies show that the Indo-Australian Plate (the sea floor that runs along Australia, Indonesia and includes the Indian subcontinent) is vulnerable to tremors and tsunami.” One was noted in the Andamans in 1941 during the Japanese invasion, but no official records are available. And just three weeks before the tsunami, Hyderabad hosted a global hazards meet where the catastrophic nature of tsunami and measures to minimise impact were discussed.

Tsunami vulnerability index

Seismologist Arun Bapat says tsunami vulnerability is deter¬mined by:

  • A potential to produce tsunamigenic earthquakes
  • A 500 km-plus distance between the seismic region and the coast
  • When only water lies between the epicentre and the coast

Going by this, the junction of the Indian, African and Arabian plates near Socotra island and the underwater Carlsberg Ridge in northern Indian Ocean, would appear to be tsunami-vulnerable. As recently as in 2003, in a paper on the Diglipur earthquake (on August 13 2002 of 6.8 magni¬tude in the North Andamans), C P Rajendran, Centre for Earth Science Studies (CESS), Thiruvananthapuram, had observed that “There is a lack of a good database on the effects of tsunami waves, to which not only the coast of Andaman-Nicobar is exposed, but also the eastern coast of India — a threat that is generally under-estimated. The paper noted it was likely the region had entered a phase of renewed seismic activity.

India needs centralised ocean management

In the US, a single body, the National Oceanic and Atmospher¬ic Administration, coordinates all oceanographic and atmos¬pheric studies. But in India, there is a multiplicity of organisa¬tions involved in oceanographic studies, under various min¬istries, and this causes an information whirlpool. To name a few:

  • Department of Ocean Development: funds for oceano¬graphic studies
  • Survey of India: maintains tidal gauges; managed by local port trusts
  • IMD: entrusted with disaster warnings, including those from the sea
  • NIO: for oceanographic research
  • Geological Survey of India: for marine geological studies, including undersea earthquakes

Why, with all these organisations, do we still lack proper data? Research on India’s strategic areas (defence, nuclear and space) gets prioritised, while modernised tide gauge systems to provide real-time data on wave behaviour gets sidelined, even if the amount involved is as tiny as Rs 10 and they, too, are operated manually. Survey of India (SoI) had in fact moot- ed a proposal to have an array of digi¬ tal tide gauges to transmit real time data by satellite to a 24-hour centre at the SoI headquarters, Dehradun. DoD also plans to double its capacity of buoys, used to measure ocean data.

India gets ready for tsunami

The Pacific Tsunami Warning Centre, set up in 1948 to mon¬itor the only ocean known to have tsunami, works with an observational system based on a network of deep sea pressure gauges. Now that tsunami have struck here, India is also con¬sidering being part of a global tsunami warning system, besides developing an indigenous one that will be built at a cost of Rs 125 crore. DoD will be the nodal agency.

Scientists have also identified six modern seismic observa¬tories of IMD at Bhuj, Andaman island, Chennai, Hyderabad, Guwahati and Delhi. If and when an earthquake of magnitude 7 or more occurs, pressure sensors deployed in the deep as part of Deep Ocean Assessment and Reporting Systems (DOARS) along the fault lines will pick up signals of pressure waves building up. It is believed that only an undersea earthquake of magnitude 7 or above can trigger a tsunami. Harsh Gupta opines that only two fault lines in India need to be carefully monitored for a potential tsunami: these are the regions around Bhuj and the Andaman sea.

But science needs now to go beyond mere technology and to start thinking of the people they’re for its ivory tower, cannot respond to disasters unless they know what’s needed on the ground and who to share information with. So ocean science, like the others, needs to be part of a wider vision. Where technology, people, administration all come together. To combat disaster impact.


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