The tsunami catcher of Velenkanni

Arumaigam is a farmer in Velankanni district of Tamil Nadu. During the
devastating tsunami that hit the TN shores on December 26, 2004, he lost his
entire land of 10 acres as well as his house. All produces were gone and his
life was in ruins. Now, years of hard work, various rehabilitation packages from
the state and central government have helped him to slowly restore some sort of
hope back in his life. But, there is always the fear lurking at the back of his
mind that another tsunami could take away everything again, and this time with
little hope of making another comeback.

So when his panchayat pradhan, Senthilnathan told him about the new tsunami
early warning system, he was more than relieved that one of his deepest
concerns has now been taken care of. Now, he would be able to receive early
warnings about an impending disaster, and that would enable him to save a large
portion of his belongings. And with features like real-time seismic data
monitoring subsystem, tide gauge data monitoring subsystem as well as bottom
pressure recorder (BPR) data monitoring subsystem and decision support system (DSS)
with GIS interface available, even the government would now be able to evacuate
Arumaigam and Senthils village residents on time and can make other provisions
to save the land.

This tsunami early warning system (TEWS) which is now giving hopes to
Arumaigam, Senthil and numerous of their ilk was envisioned as a national
importance e-governance project by the Ministry of Earth Sciences after the 2004
tsunami. The warning system was established by MoES as the nodal ministry at a
cost of Rs 125 crore in collaboration with Department of Science and Technology
(DST), Department of Space (DOS) and the Council of Scientific and Industrial
Research (CSIR). What spurred many of these government agencies was the
widespread criticism after the 2004 tsunami about the lack of such a system in
India, whereby coastal districts in most countries around the world prone to
natural calamities emanating from the sea have something in place.

TEWS was therefore a first-of-its-kind implementation in the Indian Ocean
region using IT and geospatial technologies. It provides scientists with the
necessary information for tsunami alerts through an access to real-time seismic
data, monitoring of tide gauge data, and BPRs to assess the tsunamigenic
potentiality of an earthquake. The system allows INCOIS scientists and
decision-makers to disseminate accurate tsunami alerts to the administrators and
public.

Incidentally, TCS was chosen to develop and implement the TEWS system for
INCOIS as part of the National Tsunami Early Warning Center at Hyderabad. Tanmoy
Chakrabarty, vice president and head, government ISU, TCS is justifiably proud
of the system that uses N2Model application with state-of-the-art geospatial
technology; what this technology enables is to display the model output as
layers on the maps with right symbols. Having a GIS based website and facilities
for information dissemination through emails and SMS alerts have helped TEWS
directly touch the lives of citizens in the coastal districts.

The Working Model

TEWS comprises a real-time network of seismic stations, BPRs and tide gauges
to detect tsunamigenic earthquakes and to monitor tsunamis. The early warning
center receives real-time seismic data from the national seismic network of the
lndian Meteorological Department (IMD) and other International seismic networks.
The system detects all earthquake events of more than 6 magnitude on the Richter
scale occurring in the lndian Ocean in less than twenty minutes of occurrence.

BPRs installed deep in the ocean are the key sensors to confirm the
triggering of a tsunami. The National Institute of Ocean Technology (NIOT) has
installed four BPRs in the Bay of Bengal and two in the Arabian Sea. In
addition, NIOT and Survey of India (SOI) have installed thirty tide gauges to
monitor the progress of tsunami waves.

Seismic and sea level data are continuously monitored at the early warning
center using a custom-built software application that generates alarm alerts in
the warning center whenever a pre-set threshold is crossed. Tsunami warning
watches are then generated based on pre-set decision support rules and
disseminated to the concerned authorities for action, following a standard
operating procedure. The efficiency of the end-to-end system was proved during
the large undersea earthquake of 8.4 M that occurred on September 12, 2007, in
the Indian Ocean.

The National Early Warning Center then generates and disseminates timely
advisories to the control room of the Ministry of Home Affairs for further
dissemination to the public. For the dissemination of alerts to MHA, a satellite
based virtual private network for disaster management support (VPN DMS) has been
established. This network enables the early warning center to disseminate
warnings to the MHA, as well as to the state emergency operations centers. In
addition, messages will also be sent by phone, fax, SMS and emails to authorized
officials. In case of confirmed warnings, the National Early Warning Center is
being equipped with necessary facilities to disseminate the advisories directly
to the administrators, media and public through SMS, email, and fax.

Benefits Galore

TEWS has become a key tool in mitigating potential threat to life and
property from tsunami in the Indian Ocean to Arumaigam, Senthil and nearly 400
mn other people in the coastal districts. A 24x7 monitoring facility of various
data sources of the early warning system has enabled INCOIS assess potential
calamities correctly and downgrade warnings in several situations, thus
preventing panic and saving revenue loss for subsequent evacuation activities.
Says Chakrabarty, Over the last three years of its implementation, the center
has recorded over 1,000 earthquakes of magnitude of over 5 on Richter scale and
has never issued any false alarm.

In many cases, it has accurately detected the tsunami in the Indian Ocean,
alerted affected countries surrounding the Indian Ocean and most importantly
even predicted the travel time for the tsunami to reach a particular location
along the coast. Adds Dr Satheesh C Shenoy, director, INCOIS, The system has
proved to be extremely effective in the wake of several high magnitude undersea
earthquakes in the Indian Ocean region. We have successfully used TEWS to
validate several earthquakes since its inception in October 2007, including the
most recent earthquake in April 2010 in southern Sumatra. INCOIS was able to
validate the April 2010 earthquake within ten minutes, and issue tsunami alerts
for Andaman and a tsunami watch for the main land in the next twenty minutes. No
wonder, TEWS has ensured that Arumaigam now sleeps a little more peacefully at
night. The memories of 2004 can never be erased, but chances of a repeat have
now been reduced significantly.

Shilpa Shanbhag

shilpas@cybermedia.co.in