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GENERAL:
1.
Tsunami effect, Business Line editorial dated 29/12/04.
The
environment is ultimately the people’s legacy and not that of a
faceless creature called the government. That the earth should open up
and send killer waves onto the land is proof that ancient man’s
primordial fear and reverence for nature was born neither of ignorance
nor stupidity. Water, the air we breathe, the space above and the earth
we occupy for our allotted span, and the energy fields in which we are
permanently enveloped are border less, universal and indivisible. Our
task is to stand in awe of their strength and strive to conserve them.
As the ancients knew so well, we don’t own nature but hold it in
trust for posterity.
2. Quake similar to event 120 million years ago: Geologist, The New Indian
Express dated 1/1/05
The
magnitude of the massive disaster unleashed by an enormous underwater
earthquake in the Indian Ocean, that ravaged several countries on Sunday
last, was similar to the sudden transgression of the Indo-Pacific sea,
now called the Bay of Bengal, some 120 million years ago, says a senior
geologist.
3. Indian natural hazard map tracked tsunami seven years ago, The New
Indian Express dated 3/1/05.
Though
this was no prediction of any sort, it just showed theoretically what
would happen if an earthquake of high intensity in Indonesia triggered
off a tsunami.
4. Post-tsunami India's image rises globally, The New Indian Express dated
5/1/05.
It
showed it doesn't really need these huge organisations like Oxfam etc.,
who want to get mileage out of this. Our own people have the commitment
- big and small NGOs who don't need to get on CNN.
5. Tsunami warning system, The Hindu dated ??.
Computer models can then simulate how the tsunami would propagate in the
deep ocean, also taking into account how underwater ridges and mounds
would affect the wave. Although the tsunami could be travelling faster
than a passenger jet, the wave may be only a few metres high. As a single
wave can be more than 750 km long, the slope is so gentle that a tsunami
can pass by unnoticed in the ocean.
6. More than a million Hiroshimas, The Hindu dated ??.
Compare that with the bomb that decimated Hiroshima, whose yield was similar
to that from exploding 15,000 tons of TNT. The Indonesian quake last week,
like the Chilean quake of 1960, unleashed 2.13 million times more energy
than the perversely named "Little Boy" did over Hiroshima.
7. Andamans' agony, The Frontline, issue 22 January 01-14
The
damage to human lives was much less than what it could have been. It is
ironical that the Ministry of Environment and Forests is currently undertaking
a review of the CRZ notification to allow in builders, roadmakers and
hoteliers
8.
The Tsunami phenomenon, The Frontline, issue 22, January 01-14
The series of massive ocean waves - indeed speeding walls of water - that
caused devastating inundation in the southeastern coastline of India and
the eastern coastline of Sri Lanka are known in geological parlance as
tsunami, a Japanese word meaning "harbour wave". A tsunami moves
silently but rapidly across the ocean and rises unexpectedly as destructive
high waves along shallow coastal waters, causing widespread devastation
over land along the coastline.
9.
LTTE recruiting children affected by tsunami: Human Rights Watch, uniindia.com
dated 15/1/05
The
Liberation Tigers of Tamil Eelam (LTTE) is recruiting children affected
by the tsunami for use as soldiers, the New York based Human Rights Watch
has alleged.
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1.
Tsunami effect, Editorial, Business Line dated 29/12/04.
AFTER EVERY HORRENDOUS tragedy on the scale of Sunday's tsunami, when
the mind has digested the statistics and the gory images, and the consoling
words have been said, there remains the long and hard trek back to reality,
most of all for the victims. There are cautionary lessons for others,
however, in two directions: how to manage the recovery and rehabilitation
quickly and with minimum fuss; and how to be better prepared when next
such collective trauma strikes, as it inevitably will. We might never
be able to predict precisely when and where Nature will strike next —
or how, but we could mitigate the effects through early warning.
Our first priority, therefore, is an urgent review of preparedness and
joining the international groups dealing with such disasters. The cost
of the sensing equipment can be no reason for not acting. The State governments
must bring themselves to give up some expensive pomp and ceremony and
collect their taxes more efficiently, if need be, in order to afford the
capital outlay. Second, well meant help and charity offered at this emotional
moment must be managed honestly, and the usual corruption and leakage
avoided. Third, seeking political advantage or scoring brownie points
at the expense of another party at this stage is nothing short of inhuman
and uncivilised. Instead, leaders could check what, if anything, the MLAs
and MPs concerned did to bring succour to the affected areas within the
first 12 hours. Those who did not take any action deserve to be exposed.
District and municipal administrations should build bridges with local
communities and voluntary organisations providing relief at times of great
distress. Fourth, it is essential to pool together the expertise available
in the country and organise an awareness-raising campaign society-wide
in favour of those practices that systematically protect and enhance the
sustainability of our ecosystem — and discourage the ones that destroy
it. The worst tragedies of mankind come not from randomness of Nature
but our inability to learn from experience and intelligently harness the
knowledge we already have. We don't need another unthinkable disaster
to see the obvious. Recent initiatives in social forestry, rain-water
harvesting and segregation of bio-degradable waste are examples of belated
recognition of creeping disasters that are no less lethal potentially.
The environment is ultimately the people's legacy and not that of a faceless
creature called the government. That the earth should open up and send
killer waves onto the land is proof that ancient Man's primordial fear
and reverence for Nature was born neither of ignorance nor stupidity.
Water, the air we breathe, the space above and the earth we occupy for
our allotted span, and the energy fields in which we are permanently enveloped
are borderless, universal and indivisible. Our task is to stand in awe
of their strength and strive to conserve them. As the ancients knew so
well, we don't own Nature but hold it in trust for posterity.
top
2.
Quake similar to event 120 million years ago: Geologist, The New Indian
Express dated 1/1/05.
UNI
TIRUCHIRAPALLI: The magnitude of the massive disaster unleashed by an
enormous underwater earthquake in the Indian Ocean, that ravaged several
countries on Sunday last, was similar to the sudden transgression of the
Indo-Pacific sea, now called the Bay of Bengal, some 120 million years
ago, says a senior geologist.
In
an interview to UNI here, P Chandrasekaran, who had served in the Kolar
Gold Fields in Karnataka as a geologist and is currently a consultant
on mining and geology, said the sudden transgression of the Bay of Bengal
about 120 million years ago was a precedent for the tsunami on December
26 and the coincidence was that it had again happened near the same landmass.
He
said what is now called the Ariyalur region in Perambulur district of
the Tamil Nadu witnessed this very rare event in the cretaceous period.
The Bay of Bengal moved in and occupied about one-lakh acres stretching
from Samayapuram in the South to Kunnam and Senthurai in the North and
Dalmiapuram, Kazhappalur and Vickramangalam in the East.
It
was when the sea moved in that the great Himalayan mountain range started
rising from the sea, creating a huge barrier between the Gangetic plains
and Mongolia.
The
sea stayed on for 40 million years, when another very rare event (perhaps
another geological phenomenon) took place. The sea withdrew to its original
position. In other words, present day Ariyalur, Dalmiapuram, Garudamangalam,
Melapazhur, Kunnam and Kolankkanatham regions had been submerged for a
period of 40 million years, he said.
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3.
Indian natural hazard map tracked tsunami seven years ago, The New Indian
Express dated 3/1/05
PTI
KOLKATA: The possible epicentre of the December 26 tsunami and the probable
path that the killer waves would take had been precisely tracked on the
Indian natural hazard map seven years ago.
Director
of the National Atlas and Thematic Mapping Organisation (NATMO) Dr G N
Saha told sources here on Monday that the map, made by NATMO in the late
nineties, had shown the possible epicentre in Indonesia and tsunami waves
travelling to hit the Andaman and Nicobar islands as well as the south
Indian coast.
"Though
this was no prediction of any sort, it just showed theoretically what
would happen if an earthquake of high intensity in Indonesia triggered
off a tsunami," he said.
In
view of reports of massive changes in coastline topography, island area
shift and territorial gain, the Survey of India along with the National
Institute of Oceanography, Goa and the Naval hydrography wing had already
begun ground surveys to verify data pertaining to this.
"There
are unconfirmed reports of land area changes and after the team undertakes
an overall survey of the island beginning January 10, we will be in a
position to find out if we need to make new maps for the Andaman and Nicobar
islands," he said.
Meanwhile,
the Space Application Centre, Ahmedabad and the National Remote Sensing
Institute in Hyderabad released pictures beamed by Ikonos and RESOURCESAT
satellites suggesting that many isles had been marooned and settlements
in many had been shattered.
Saha
said the Ministry of External Affairs and the Union Department of Science
and Technology had sought the Indian ocean atlas that tracked the adjoining
countries, the sea surface temperature, wave pattern, wind direction,
placement of islands and other coastal information.
Sources
at the Geological Survey of India (GSI) said that changes in the landmass
could not be suggested with any precision unless a Ground Positioning
System (GPS) survey was undertaken over a long period of time.
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4.
Post-tsunami India's image rises globally, The New Indian Express dated
5/1/05
IANS
WASHINGTON: India has displayed maturity in its management of the ravages
caused by last week's tsunami - helping other countries in the region
and in helping itself - leading to a changed perception of the country
in the eyes of the international community.
"It's
a new and confident India which also recognizes its responsibilities,"
asserted renowned economist Jagdish Bhagwati.
In
an interview with IANS, Bhagwati says in helping other countries around
the world in its own time of crisis, "It's not just international
power play but rather a display of maturity. It's not with a sense of
pride but rather as an obligation."
"There
will be a changed perception of India following this disaster," says
Anirban Basu, former director of the Towson University Regional Economic
Studies Institute in greater Washington.
"India
is not just a technical leader in South Asia and Southeast Asia, but a
leader in taking up the tsunami warning system. I think people have looked
at India till now not much more than a leader in South Asia," said
Basu, CEO of Sage Policy Group, advisors to state, federal and private
companies.
New
Delhi promptly began helping Sri Lanka with ships and army personnel to
reach difficult areas and deliver aid, even as it coped with its own death
toll that touches 9,000 with thousands still unaccounted for.
"The
fact that it is able to take care of itself also comes out in the Bush
administration's response - and the work of the Indian government which
has cemented the bond - President Bush clubbed India with Japan and Australia.
So it has worked out very nicely for India's image even for altruistic
purposes," Bhagwati emphasized.
"India
also took matters in stride although it did not suffer as huge a loss
as Sri Lanka or Indonesia," Bhagwati noted.
"It
showed it doesn't really need these huge organisations like Oxfam etc.,
who want to get mileage out of this. Our own people have the commitment
- big and small NGOs who don't need to get on CNN," he added.
"Ultimately,
Indian ships are going out to help, just like the US - that shows its
status."
Bhagwati
indicated he was most impressed by the non-governmental organizations
in India that have fuelled the "revolution of perceived possibilities
and rising expectations".
India,
he said, "is both a democracy and a major force", and NGOs had
helped make the democracy more responsive to people. "These NGOs
provide people with their sense of confidence, not necessarily the political
parties."
According
to Anirban Basu, India's aid effort in the region was "an amazing
transformation" for a country that was an aid recipient at one time.
Though
it still may get aid from organizations like the World Bank "India
is a powerhouse in so many ways but also houses a very large community
of poor, and there is no shame in that," Basu insisted.
"India
will remain a study in contradictions - home to cutting edge technology
and also to millions of poor, but a rising tide lifts all boats,"
he said metaphorically without intending a pun in the current disaster.
5. Tsunami warning system, The Hindu dated??
By N. Gopal Raj,
A WARNING of an oncoming tsunami is more than a matter of detecting that
an earthquake has occurred under or near an ocean. The experience in the
Pacific Ocean, where most tsunamis happen, is that a number of complex
steps have to be completed rapidly so that people can be evacuated to
safer locations. Yet the system must also be robust enough to avoid false
alerts, which would unnecessarily disrupt people's lives, cause substantial
financial loss and ultimately lead to a loss of confidence in the system.
Unlike in the Pacific where over 790 tsunamis have been recorded since
1900, Sunday's tsunami was just the second to hit India during the same
period. The first tsunami to reach the Indian mainland in the last 100
years was in 1941. Before that, a tsunami was recorded in December 1881.
Moreover, not every earthquake under or near the ocean causes a tsunami.
About a dozen earthquakes of over magnitude 5 on the Richter scale have
occurred in the vicinity of the Andaman and Nicobar islands since 1973,
including two greater than magnitude 6. According to officials of the
National Institute of Oceanography in Goa, no tsunamis followed. The magnitude
9 earthquake off Sumatra, which caused Sunday's tsunami, set off several
earthquakes in the Andaman and Nicobar islands, including one that exceeded
magnitude 7. None of these later earthquakes is known to have caused tsunamis
that reached the Indian mainland.
In 1965, the Intergovernmental Oceanographic Commission (IOC) of the United
Nations Educational, Scientific and Cultural Organisation (UNESCO), established
the International Tsunami Information Center (ITIC) in Hawaii. Three years
later, the IOC formed an International Coordination Group for the Tsunami
Warning System in the Pacific, with 26 countries in and around the Pacific
as its members. The system issues tsunami information and warnings to
over 100 places scattered across the Pacific.
Three distinct but overlapping physical processes have to be modelled
accurately in order to understand whether an earthquake could have set
off a tsunami and then to identify the places at risk. At the Pacific
Tsunami Warning Center (PTWC) in Hawaii, computer systems continually
monitor data from seismic stations in the United States and abroad, and
alert watch-standers whenever a significant earthquake has been detected,
says Charles McCreery in a recent issue of the Tsunami Newsletter. "If
the earthquake is shallow and is located under or very close to the sea,
and if its magnitude exceeds a predetermined threshold, a warning is issued
based on there being the potential that a destructive tsunami was generated."
Such computation is based on 30 to 50 independent measurements and, as
Dr. McCreery points out, the PTWC's performance improved rapidly as high-quality
seismic data from more seismic stations in the U.S. and other countries
became available in real time. The time the PTWC needed to issue a warning
fell from up to 90 minutes six years ago to the present level of 25 minutes
or less.
It is reported that there are about 200 seismic observatories in the country
under various organisations. The India Meteorological Department has some
58 seismic stations under it, only 17 of which are digital and networked.
More Indian seismic stations must be networked so that their data immediately
become available for analysis, says Kusala Rajendran of the Centre for
Earth Science Studies in Thiruvananthapuram.
At least 10 parameters about the fracture in the earth's crust that caused
the earthquake are needed to predict the tsunami's initial height, according
to Frank Gonzalez, Tsunami Research Program Leader at the U.S. National
Oceanic and Atmospheric Administration (NOAA). As only the orientation
of the fracture and the quake's location, magnitude and depth can be obtained
from the seismic data, all the other parameters must be estimated, he
said in a 1999 article in the Scientific American. Consequently, the tsunami's
height can be initially misjudged.
Computer models can then simulate how the tsunami would propagate in the
deep ocean, also taking into account how underwater ridges and mounds
would affect the wave. Although the tsunami could be travelling faster
than a passenger jet, the wave may be only a few metres high. As a single
wave can be more than 750 km long, the slope is so gentle that a tsunami
can pass by unnoticed in the ocean.
After the first indication that an earthquake may have triggered a tsunami,
"it is necessary to wait until a potential tsunami reaches the nearest
sea level gauge to confirm or deny its existence and begin to evaluate
its character," says Dr. McCreery. There are currently about a hundred
such gauges around the Pacific, most of which can transmit their data
via satellite back to the warning centres. But as these gauges are typically
located in the harbours and protected bays, the characteristics of the
tsunami would be greatly modified by the shallow depth. That severely
limits the usefulness of the data from the gauges, according to Dr. McCreery.
Consequently, the NOAA developed the `Deep Ocean Assessment and Reporting
of Tsunamis' (DART) gauge. Each DART gauge has a highly sensitive pressure
recorder installed on the ocean floor. From a depth of 6 km, the recorder
is capable of detecting if the height of the ocean above it changes by
just one cm. This data is transmitted acoustically to a surface buoy that
then relays it over satellite to the warning centre. Seven DART gauges
have already been deployed, and at least four more are being planned.
The DART gauges are sited in deep water so that they can accurately record
the tsunami waves as they pass unaltered, remarks Dr. McCreery.
As the tsunami approaches the shore and the depth decreases, the waves
slow down but become higher. The last stage of evolution where the tsunami
comes ashore as a breaking wave, a wall of water or a tide-like flood
is perhaps the most difficult to model, according to Dr. Gonzalez. Wave
heights can reach tens of metres, although waves two to three metres high
are sufficient to cause damage.
The NOAA has developed a suite of computer models, collectively known
as the MOST (Method of Splitting Tsunami), which are capable of simulating
the generation of a tsunami, its transoceanic propagation and inundation
of dry land. But the NOAA also points out: "The current state-of-the
art in tsunami modelling still requires considerable quality control,
judgment and iterative, exploratory computations before a scenario is
assumed to be reliable. This is why the efficient computation of many
scenarios for the creation of a database of pre-computed scenarios that
have been carefully analysed and interpreted by a knowledgeable and experienced
tsunami modeller is an essential first step in the development of a reliable
and robust tsunami forecasting and hazard assessment capability."
In Japan too, "virtual tsunamis" have been pre-calculated for
thousands of possible sources for various magnitudes of earthquake from
6.5 upwards. A supercomputer sorts these "virtual tsunamis"
when an earthquake occurs and makes the extrapolations necessary when
it does not correspond precisely to any one of them.
Issuing a reliable warning is just the first step. It is then up to the
civilian authorities to use the warning for evacuations. Plans have to
be made and rehearsed so that all the agencies act quickly and in concert
once an alert is issued. Sunday's tsunami swept across the ocean and reached
India in just two hours. Countries who currently receive international
tsunami warnings have found that they do not have the emergency response
capacity, and the necessary communications infrastructure. Hence even
though a warning may be received, their coastal communities are still
extremely vulnerable.
Establishing a reliable and robust tsunami warning system for India is
therefore a substantial undertaking. Many Indian seismic stations probably
require upgradation and also need to be networked. The seismic station
at Port Blair in the Andamans is, for instance, said to be of the old
analog type. Sea-level gauges are needed and press reports say that the
Government is looking at installing DART-type gauges. Simulation software
that model the evolution of tsunamis from generation to landfall may need
to be modified to suit the Indian situation. Hazard mapping to identify
vulnerable areas would also probably be required. The satellite-based
cyclone-warning system can be augmented for disseminating tsunami warning.
Most important of all, local-level plans have to be drawn up for evacuating
people at short notice. Joining the international tsunami warning system
will help, but even so there will be much that has to be done within the
country.
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6 More than a million Hiroshimas, The Hindu, By P. Sainath,
Will Governments ever spend the modest sums required along the coast to
protect the millions of poorer Indians dependent on the seas?
THE EARTHQUAKE that produced the tsunami unleashed energy millions of
times greater than the Hiroshima bomb. True, comparisons across different
physical processes are not straightforward. Yet it is quite common to
restate the magnitude of earthquakes in terms that are more familiar.
Typically, this is done by asking how much of the common explosive Trinitrotoluene
(TNT) would have to be detonated to obtain the same release of energy
as the earthquake.
A table produced by the Nevada Seismological Laboratory suggests that
a quake of 9.0 on the Richter scale has a seismic energy yield roughly
equalling 32 billion tons of TNT.
Compare that with the bomb that decimated Hiroshima, whose yield was similar
to that from exploding 15,000 tons of TNT. The Indonesian quake last week,
like the Chilean quake of 1960, unleashed 2.13 million times more energy
than the perversely named "Little Boy" did over Hiroshima.
As geophysicist and climatologist Ashwin Mahesh points out, "Such
a look across different processes is tricky. This cannot be a straight
comparison but simply a useful indicator of power that ordinary people
can relate to. Also, Hiroshima was an `atmospheric' blast, not on the
ground. Then there is radiation damage, which additionally occurs with
nukes. Not with quakes. Finally, there is the impact — nearly all
the energy from an atomic bomb is released locally, but energy from an
earthquake is distributed by seismic action and more widely dispersed.
This is why something that happened in Indonesia still packs a punch thousands
of miles away from the epicentre."
Dr. Mahesh is, of course, quite right. Yet, the comparative numbers do
convey a sense of the sheer magnitude of the quake's power. And apart
from the physical and character differences of the two processes, the
quake in this case also triggered the devastation that spilt across 12
countries and two continents. It will be ages before we fully measure
the damage.
There has been much agonising over "those vital three hours"
(now spoken of as 90 minutes) in which the Government "could have
done something." Sure, it is always useful to be forewarned of disaster.
Every human life saved is worth the effort. Yet, there was little scope
for a major response, even if India had been part of the tsunami warning
system. (Of course this did not stop sections of the media from identifying
the villains and the good guys within six hours of the event.)
Without a network of local alarm systems in place along the coast, membership
in the warning system club would have meant little. Those networks would
have to be of a kind that did not depend wholly on human agency. That
is, they should not need someone to switch them on or off. The coastal
disaster struck in the early hours of the morning, when all offices and
institutions were closed.
`Local administration,' such as there was, was also crippled by the event.
Policemen, municipal workers, clerks, low-level officials, engineers,
medical personnel, and many others, also died in the disaster. Roads were
inaccessible, vehicles washed away, electricity shut down. A highly-skilled,
ready-round-the-clock entity like the Indian Air Force had a base wrecked
(it took a beating during the Gujarat earthquake, too). Many of those
we assume could have done a lot in those 90 minutes were themselves victims
of the catastrophe.
The nuclear site at Kalpakkam was hampered by more than the direct impact.
A design engineer employed by the facility was swept away by the waves
while praying in Church. Other employees too died. The apocalyptic scale
of disaster ensured a chaos on the ground that paralysed most systems.
The blame game unfolding within hours of the tragedy is mystifying given
that few explain what they would have done in those 90 minutes had they
got the warning. Warnings without practised, in-place response strategies
and drills might have meant little. Certainly at that hour. (Incidentally,
one channel announced that Besant Nagar in Chennai was "under water,"
leading to panic — outside that locality.) We may not have been
able to do much in those 90 minutes. But every little thing we do now
matters enormously. What is needed is urgency on the relief and rehabilitation
front and a rational long-term response to disaster.
It is also a little mystifying that the India Meteorological Department
is seen as having a major role in the present mess. Tsunami are not weather
phenomena. If anything, monitoring events that might trigger them could
be the task of the Geological Survey of India (GSI). But that is another
story. Where indeed Governments must be blasted is for the quality and
tardiness of relief efforts. Not for failing to predict the impact of
tsunami.
It is also another matter, as John Schwartz points out in The New York
Times, that 75 per cent of tsunami warnings in 56 years have been wrong.
He quotes a NASA website devoted to tsunami as saying "Three out
of four tsunami warnings issued since 1948 have been false. And the cost
of the false alarms can be high." Already, the panic over the "high
wave alert" is an embarrassment for a defensive Government trying
to cope with the media charge that it did not respond the last time.
The January 17, 1995, Kobe earthquake in Japan took 5,500 lives, injured
26,000 and inflicted damage in excess of $ 200 billion. That in a country
where seismic activity is massively monitored with advanced technologies.
The quake lasted some 20 seconds and measured around 7.0 on the Richter
scale. Structures designed for such seismic zones were torn apart like
paper. Last week's quake measured 9.0. Which means it was, near Indonesia
at least, 1,000 times more powerful than Kobe (The Richter scale is a
logarithmic one, not a linear scale.)
The question is not so much whether India should have been a paid-up member
of the tsunami warning system. Until last week, elite wisdom would have
viewed that as so much money saved. The question is whether Governments
in India today will ever spend the modest sums required along the coast
to protect the millions of poorer Indians dependent on the seas. And whether
we need a disaster this scale to rethink some of our priorities.
The surprise expressed by many (arriving from Delhi) over the poor medical
facilities in these regions is misplaced. The capital city may have such
facilities. But we have spent the better part of 12 years gutting public
health care, privatising hospitals and charging user fees in Government
ones from people who cannot pay. Fracturing an already inadequate and
fragile system. Now, when there is a deadly danger of epidemics, there
is little to fight them with. It is odd that we allow Governments to get
away with atrocities against the poor. But sternly hold them to blame
for an unprecedented natural disaster.
Hundreds of fishing villages have been squeezed into narrower, tighter
settlements as `development' Indian-style sets in. Many have moved into
unsafe terrain, pushed by resorts, hotels, construction of highways. Mangrove
forests that have always acted as a brake — however limited —
against tidal waves, have increasingly vanished. So have another natural
barrier — sand dunes, looted by the construction industry. We have
put a lot of effort into making the coastline increasingly unsafe.
And not just the coastline. There seems to be no concern over the fact
that the many small dams in the western part of the country might be responsible
for what is known as `reservoir-induced seismicity.' Our planners still
aim to turn every river into a chain of lakes.
Growing seismic activity in Maharashtra has not led to a rethink on the
ever-higher skyscrapers being planned there. Especially in Mumbai city.
Nor has the harrowing experience of the Gujarat earthquake had any impact
on Mumbai's mighty builder lobby. We could perhaps have done very little
in "those crucial 90 minutes," but there is much we can do on
other fronts, if we wish to, to make people safer.
It would not be too much of a challenge to India's much-celebrated IT
and software genius to make the lives of traditional fishermen along India's
coastline a lot better. A PCO type box, modified for at-sea use could
do plenty. It could act as a weather alert and SOS mechanism. It could
work as a GPS device. It could even be used to help fishermen in shoal
tracking — a huge advantage that predatory big boats and trawlers
have over them. All in all, it might be possible to install these in the
vessels of traditional fishermen at maybe less than Rs.2,000 a boat. It
is a small thing that may have little to do with tsunamis. But it could
make a big difference in many life-threatening situations.
That it has never happened on a major scale means it is just not a priority.
When advanced technological systems do come in, they will likely be installed
with an eye on tourists rather than fisherfolk. The latter, right now,
do not even have boats on which to install any safety device. Thousands
of boats, catamarans and fishing nets were simply destroyed in the calamity.
Maybe we can never fully and correctly predict a tsunami or, more importantly,
its likely impact. On the other hand, it is easy to predict that our priorities,
our ways of thinking and living, render us vulnerable to disasters of
our own making.
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7. Andamans' agony, The Frontline, issue 22 January 01-14
PANKAJ SEKHSARIA
AS the crow flies, Great Nicobar, the southern-most island in the Andaman
and Nicobar group, is only about 150 km from Aceh in Sumatra, the epicentre
of the devastating earthquake. So the impact of the tsunamis it triggered
on the Andamans, particularly the Nicobars (which have a population of
nearly 45,000), can well be imagined. After the first shock of a magnitude
of 8.9 on the Richter scale hit Aceh at 6-30 a.m. IST, a second one, measuring
7.3, occurred at around 9 a.m. with its epicentre at Indira Gandhi Point,
the tip of the Great Nicobar Island.
The relatively flat island of Car Nicobar, which has a population of nearly
25,000, mostly Nicobarese, was the worst affected. The Indian Air Force
(IAF) base in Car Nicobar was washed away. Reports indicated on the morning
of December 27 that at least 1,000 people had died in the islands, with
300 confirmed casualties from Car Nicobar alone. This included 23 IAF
men and their families. Lieutenant-Governor Prof. Ram Kapse flew to Car
Nicobar in the afternoon of December 26 to inspect the scene and supervise
the rescue operations.
Considering the distance, remoteness and inaccessibility of the islands,
little information was forthcoming even until late in the evening of December
26, even as the islands continued to experience tremors and aftershocks.
Large parts of Port Blair went without power supply until late in the
evening and telecommunications, too, were affected.
In Port Blair waves six metres high damaged the coastal front facing the
Jawaharlal Nehru Rajkiya Maha Vidyalaya, a popular tourist spot. Several
multi-storeyed concrete buildings that came up in the islands, particularly
in Port Blair, in the past few years either collapsed or suffered damage.
Cracks rendered the airstrip in Port Blair unusable, but some landings
did take place later in the day.
The main wharf in Port Blair at Haddo, the Phoenix Bay Jetty, where most
of the inter-island shipping originates and jetties in other islands such
as Havelock and Neil, located east of Port Blair, were also damaged. Serious
concern has been expressed about the damage on Great Nicobar, although
there was absolutely no information from there at the time of writing.
Not only is it closest to the epicentre, but its population of nearly
7,000 people is settled along a narrow strip on the island's eastern coast.
Similarly, there was no news from the Central Nicobars, which have a population
of nearly 12,000 spread over 10 islands, and the Little Andaman with an
estimated 12,000 people. There have also been no reports from the Middle
and North Andaman Islands, which have substantially larger human populations;
about 45,000 and 30,000 respectively.
"What has happened is unfortunate," said Debi Goenka of the
Bombay Environment Action Group, when contacted, " but thanks to
the Coastal Regulation Zone (CRZ) notification and the mangroves that
protect our coasts, the damage to human lives was much less than what
it could have been. It is ironical that the Ministry of Environment and
Forests is currently undertaking a review of the CRZ notification to allow
in builders, roadmakers and hoteliers," he said.
The Andaman and Nicobar Islands are known to be seismically active. The
strongest recorded earthquake in the islands was in 1941 and measured
8.1 on the Richter scale. It caused considerable damage, although the
total population in the islands then was less than 50,000. Today the islands
have an estimated population of five lakhs.
The most recent earthquake, with a magnitude of 6.4, hit North Andaman
in September 2002. It was located in the sea, 24 km south-southeast of
Diglipur, the major township in the north in the islands.
According to the September 2002 newsletter of the Society for the Andaman
and Nicobar Ecology, a unique phenomenon occurred at Campbell Bay in Great
Nicobar on April 10, 1987, where the Andaman Lakshadweep Harbour Works
was constructing a breakwater. Huge waves overtopped the partly constructed
breakwater. A team of officers went to the site for inspection. One wave
sucked four engineers into the sea and carried away a crane from the construction
site. The phenomenon was examined and found to be the effect of some underwater
seismic activity.
The area experienced continuous tremors for more than a month in 1982,
which caused extensive damage.
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8. The tsunami phenomenon, The Frontline, issue 22 January 01-14
R.
RAMACHANDRAN
THE series of massive ocean waves - indeed speeding walls of water - that
caused devastating inundation in the southeastern coastline of India and
the eastern coastline of Sri Lanka are known in geological parlance as
tsunami, a Japanese word meaning "harbour wave". A tsunami moves
silently but rapidly across the ocean and rises unexpectedly as destructive
high waves along shallow coastal waters, causing widespread devastation
over land along the coastline.
Tsunamis are relatively rare in the Indian Ocean region but not unprecedented.
Most tsunamis occur in the Pacific Ocean and 86 per cent of them are the
products of undersea earthquakes around the Pacific Rim, where collisions
of tectonic plates result in what are known as subduction zones. During
the 1990s, as many as 82 tsunamis were reported worldwide, a rate stated
to be much higher than the historical average of 57 a decade. The last
10 major tsunamis have consumed more than 4,000 lives. But the present
one, which started out from the Sumatra coast in Indonesia and affected
countries in the Indian Ocean region, including India, Sri Lanka and Thailand,
has claimed more lives than the last 10 put together.
Though often referred to as "tidal waves", a tsunami has nothing
in common with normal wind-driven sea waves and tides. Breezes blowing
across the ocean cause waves of short wavelengths - the crest-to-crest
distance - on the sea surface. These waves cause currents that are mainly
confined to a shallow oceanic layer beneath which one has relatively calm
water. Strong winds may be able to generate even 30-metre-high waves in
the open ocean but even these do not move the deep waters. Tides, which
occur all over the earth twice a day, do produce currents that reach the
ocean bottom - just as tsunamis do - but these too are of shorter wavelengths
as compared to tsunamis.
Tsunamis are not generated by the gravitational pull of the moon or the
sun. These are produced impulsively by an undersea earthquake, and rarely
by volcanic eruptions, meteorite impacts or underwater landslides. Indeed,
the deadliest tsunami in recorded history followed the eruption and virtual
obliteration of Indonesia's Krakatoa volcano in 1883, which killed an
estimated 36,000 people, most of them owing to the tsunamis that resulted.
Simply put, terrestrial earthquakes are associated with ground shaking
that is a result of elastic waves travelling through the solid earth.
Tsunamis, on the other hand, are caused by submarine earthquakes that
set off waves with long wavelengths in water and the most destructive
tsunamis are caused by subduction zone earthquakes.
A subduction zone is where two of the earth's rigid tectonic plates are
converging towards one another (roughly at few centrimetres per year),
and one plate, usually composed of heavier oceanic material, dives beneath
the other generally lighter plate of continental material. At the boundary
where the two rub against each other, the lower one drags and flexes the
top one slightly downward. When the flexing exceeds the frictional strength
of the inter-plate contact, the upper plate rebounds to its original position
causing sea-floor displacement much like the swimming spring-board. This
happens so quickly that the sea surface assumes the shape of the sea-floor
displacement.
The potential energy of displacement is converted into the kinetic energy
of horizontal motion. This disturbance propagates outward as a tsunami.
And the wave height will at best be a couple of metres. Unlike a tidal
wave, a tsunami extends deep down into the ocean waters. That is, a tsunami
crest is just the very tip of a very vast mass of water in motion. Within
several minutes of the quake, the initial tsunami will split into one
that travels out to the deep ocean (distant tsunami) and another that
travels towards the nearby coast (local tsunami). The height above the
mean sea level (MSL) of the two oppositely travelling tsunamis is about
half that of the original tsunami.
The speed at which both travel varies as the square root of the water
depth. Therefore, deep ocean tsunamis travel faster than local tsunamis.
In the deep ocean, this wave travels at speeds of 500-1,000 km/hr. That
is, the slope of the wave - which extends hundreds of kilometres - is
so gentle, that even ships travelling on top of a tsunami wave will not
feel it. Because the momentum of the tsunami is so great, it can travel
great distances with little loss of energy. The 1990 Chilean tsunami had
enough force to travel for 22 hours across thousands of kilometres to
kill people in Japan.
As
the tsunamis (both local and distant) approach the shallow coastal waters,
their wavelength decreases and the amplitude increases several fold. As
the waves hit against the slope of the coastline, the long waves pile
on one another and the wavelength is reduced while the amplitude increases.
As the waves travel over the near-shore region, a tsunami `run-up' occurs.
Run-up is a measure of the height of water observed onshore above MSL.
Tsunamis do not result in breaking waves like the normal surf waves on
a beach. They come in like very powerful and fast local rises in sea level
and travel much farther inland than normal waves. Much of the damage inflicted
by tsunamis is on account of strong currents and floating debris.
After run-up, part of the tsunami energy is reflected back to the open
ocean. In addition, a tsunami can generate a particular type of waves
called edge waves, which travel back and forth, parallel to the shore.
The geometry of the seafloor warping near the coast has a significant
influence on this. These effects result in repetitive arrivals of the
tsunami waves at a particular point on the coast rather than a single
wave. Because of the complicated behaviour of the phenomenon of the waves
near the coast, the first run-up of a tsunami is often not the largest,
emphasising the importance of not returning to the beach for several hours
after a tsunami hits. In certain cases, the sea can seem to draw a breath
and empty the coast. This is almost immediately followed by a wall of
water inundating the coast.
The December 26 tsunami that hit South-East and South Asia is clearly
the biggest ever, in terms of the earthquake that triggered it as well
as the extent of destruction it caused, in recent history. This, according
to the United States Geological Survey (USGS), is the fourth largest earthquake
in the world since 1900 and the largest since the 1964 earthquake in Prince
William Sound, Alaska. The causative sea disturbance was an earthquake
of magnitude above 8.5 on the Richter scale - the most recent value given
by the USGS is 9.0 - whose epicentre was off the west coast of northern
Sumatra (3.3° N, 95.78° E) and at 10 km depth. The quake occurred
at 0059 hours Coordinated Universal Time (UTC - same as Greenwich Mean
Time or GMT). The location is 250 km south-southeast from Banda Aceh,
Sumatra, 1,260 km south-southwest of Bangkok and 1,605 km northwest of
Jakarta.
The eastern Indian coast in Tamil Nadu is about 2,000 km from the epicentre.
The wave appears to have hit Cuddalore first, barely one and a half hours
after the event. That makes the tsunami that hit the Indian coast to be
an extremely fast one, with a speed of about 900 km/hr. The first wave
to hit Chennai, according to the Surveyor General of India, was at 0840
hours Indian Standard Time (IST); Machilipattam was struck at 1000 hrs.
The Survey of India (SoI) maintains tidal gauges along the eastern coast.
There are only three of them located in the affected region: Chennai,
Nagapattinam and Tuticorin. Apparently, all three have been destroyed
in the disaster. Therefore, only rough estimates of the run-up is available.
The ports, however, maintain what are known as tide poles with markings
on them. The Chennai Port recorded a tidal wave height of 4.1 metres,
while the Ennore Port Trust recorded 3.5 m. The normal maximum tolerance
that these ports are designed to handle is about a metre of tide. These
are, of course, rough parameters, and the SoI is trying to determine the
exact values.
The subduction that caused the earthquake appears to have been a massive
one. The "shallow thrust-type" earthquake, according to the
USGS, occurred at the interface between the Indian and Burmese tectonic
plates. In this region, the Burmese plate is characterised by significant
strain partitioning owing to the oblique convergence of the Indian and
Australian plates to the west and the Sunda and Eurasian plates to the
east. Off the west coast of northern Sumatra, the Indian plate moves in
a northeastward direction at about 5 cm a year relative to the Burmese
plate. According to USGS, preliminary locations of larger aftershocks
show that approximately 1,000 km of plate boundary slipped as a result
of the main Sumatra earthquake. Aftershocks are distributed along much
of the shallow plate boundary between Northern Sumatra (3° N) to near
Andaman Island (14° N). Indeed, Andaman has experienced a series of
aftershocks, most of them of magnitude 5.5-6.5 and one as high as 7.3
on December 27 at 0421 hr UTC.
The Andaman region itself is seismically very active. The earliest recorded
tsunamis on the eastern Indian coast are, in fact, because of subduction
events off the Car Nicobar island. The first was on December 31, 1881,
which had a magnitude of at least 7.5. A more recent tsunami event is
that of June 26, 1941, which had a magnitude of at least 8.5. Both caused
fairly severe damage to masonry and other structures on the coast. The
number of deaths that these may have caused is not known.
top
9.
LTTE recruiting children affected by tsunami: Human Rights Watch, uniindia.com
dated 15/1/05
Washington,
Jan 15 (UNI) The Liberation Tigers of Tamil Eelam (LTTE) is recruiting
children affected by the tsunami for use as soldiers, the New York based
Human Rights Watch has alleged.
Human
Rights Watch said that the Tamil Tigers, who were already recruiting large
numbers of child soldiers, now may seek to replace forces lost to the
tsunami with child recruits.
The
United Nations Children's Fund (UNICEF) has reported three cases of children
recruited from camps for tsunami survivors in Batticaloa and Ampara on
Sri Lanka's eastern coast, the group said.
Human
Rights Watch said it has received additional information on LTTE recruitment
of children in Trincomalee and Jaffna.
''The
Tamil Tigers are preying on the most vulnerable by taking advantage of
children who have been orphaned or displaced by the tsunami,'' said Jo
Becker, children's rights advocacy director for Human Rights Watch.
''Every
effort must be made to stop this unconscionable recruiting from families
who have already suffered so much.'' The rights group said that at a relief
camp in Trincomalee, a 16-year old boy recruited prior to the tsunami
and who later escaped told credible sources he recently witnessed the
LTTE recruit three girls from the camp.
In
Jaffna, independent human rights monitors documented LTTE recruitment
of two 13-year old boys on January 3, it added.
The
LTTE, it said, had a long history of recruiting children as soldiers.
The
Human Rights Watch said a report published by it in November 2004 documented
LTTE recruitment of thousands of children since a ceasefire between the
government and LTTE took effect in early 2002.
Human
Rights Watch found that the LTTE often used threats, intimidation and
even abduction to bring children into its ranks, the report added.
''As
the LTTE seeks to rebuild its forces after the tsunami, children are at
enormous risk,'' said Mr Becker. ''Children have always been targeted,
but children who have lost their homes or families from the tsunami now
are even more susceptible to LTTE recruitment.'' Human Rights Watch called
for intensive international monitoring of camps for tsunami victims, with
special attention to vulnerable children. It urged international governments
providing aid to affected areas in Sri Lanka to publicly condemn the LTTE's
recruitment of children and call on the LTTE to release the children in
its ranks.
The
organisation welcomed UNICEF's efforts to register all orphaned and separated
children and monitor under-age recruitment cases.
top
10. The Pacific system, by R. Ramachandran, The Frontline dated 11/2/05.
THE Pacific tsunami warnings issued by the Hawaii-based Pacific Tsunami
Warning Centre (PTWC) on its network are, in general, based on seismic
data and coastal tide observations. Although operational, the system is
in a state of evolution and improvement.
A recent newsletter of the Pacific Tsunami Information Centre (PTIC) explains
how the system works. Seismic waveform data streams from a network of
seismic stations are continually monitored at the PTWC. The `watchstanders'
are alerted whenever large and widespread signals are detected from a
significant earthquake. The watchstanders quickly locate the earthquake
hypocentre and estimate its magnitude. If the earthquake is shallow and
is located under or very close to the sea, and if its magnitude is more
than a certain threshold, a preliminary warning is issued as the situation
has the potential to generate a destructive tsunami.
The only way to determine if a tsunami has been generated is to study
the sea level data from nearest gauges. These measurements are combined
with historical data and other predictive techniques such as numerical
simulation. Based on this evaluation of the level of threat, the warning
may be continued, upgraded or cancelled. The procedures are the same for
destructive local and distant tsunamis.
According to Charles McCreery of the PTWC, over the past several years,
the PTWC's operational capabilities have been considerably enhanced as
a result of various improvements in the system. These include vastly improved
quality and quantity of seismic data, improved methodologies for rapid
earthquake analysis, better spatial coverage of coastal tide gauges and,
most important, the locating of newly developed deep ocean tsunami detectors,
or tsunameters, at seven strategic points in the Pacific. Operational
forecasting now also makes use of pre-computed numerical models into which
real-time seismic and sea level data are fed. The utility of this has
now been apparently well demonstrated. But it must be pointed out that
tsunameter-based forecasting is still in research mode and is yet to be
tested in a real tsunami generating seismic event.
Critical to the accurate determination of earthquake parameters is the
availability of high quality real-time digital data from the network of
seismic stations in the Pacific region and outside. Since 1997, real-time
data from the broadband data servers of programmes like the International
Deployment of Accelerometers (IDA) are being used towards this end. According
to McCreery, the new high-quality seismic data and extensive geographical
distribution of data sources, now enable rapid and accurate determination
of earthquake parameters. Typically, the final values are based on 30
to 50 independent measurements. As a result of this, the elapsed time
between a quake and the issuance of a PTWC warning bulletin has come down
from 30 to 90 minutes some years back to 20 to 60 minutes. This improved
response time would be critical for areas at risk closer to the source
of the event.
As regards sea level data, the system makes use of the network of about
100 coastal gauges and located around the Pacific. The centre receives
the coastal sea level data from these via satellite from stations around
the Pacific. However, tidal gauge data have a limitation when applied
to the problem of tsunami forecasting. As a result, a conservative tsunami
warning philosophy has prevailed, leading to an unacceptably high false
alarm rate of 75 per cent. Indeed, having experienced false alarms in
the past, Thailand, a member of the network, did not respond quickly enough
to the warning from PTWC following the Sumatra quake.
The
tide gauges are generally fixed to land in the shallow protected waters
of harbours and bays to ensure that they last longer and can be easily
maintained on a routine basis. But in these environments tsunami waves
coming in from the open oceans are highly modified in non-linear ways
as they shoal and interact with the coast, thus severely limiting the
utility of these signals for prediction. Also the spacing between the
gauges is not always such as to sample the wave optimally. The only way
to be sure whether a tsunami wave is headed toward a distant coast is
to place tsunami detectors in its path and track it across the open ocean,
points out Frank Gonzalez, leader of tsunami research programme at the
United Sates National Oceanic and Atmospheric Administration (NOAA).
Towards this, the Pacific Marine Environmental Laboratory (PMEL) of NOAA
has developed a gauge for measuring tsunamis in deep ocean and sending
the data back to the warning centre in real time. These tsunameters, called
Deep-ocean Assessment and Reporting of Tsunamis (DART) gauges, can accurately
measure the tsunami from the pressure created on the deep ocean floor
by the undulating mass of water carried by the tsunami wave as it passes
(see diagram). The DART system is said to be sensitive to pressure changes
caused by tsunamis with amplitude as small as 1 cm in 6,000 metres of
water. This kind of accuracy is essential because tsunamis in mid-ocean
have amplitudes of the order of a few centimetres only.
THE DART system consists of an anchored pressure transducer based Bottom
Pressure Recorders (BPRs) that communicates with a moored ocean-surface
buoy in real time. An acoustic link transmits data, which are 15 seconds
averaged measurements of pressure exerted by the overlying water column.
From the buoy, the data are sent to the warning centre via a satellite
link. At present, seven such systems have been deployed in the Pacific,
six of which are operated by the U.S. and one by Chile. Four more are
being planned.
Under benign conditions, when the BPR senses regular variations characteristic
of normal tides, the buoy transmits 15-minute data every hour. However,
when a tsunami passes, the onboard algorithm switches to the tsunami mode
and transmits data every few minutes with the wave being sampled at a
much higher rate. Since BPRs are sited in deep water, they can record
accurately the nature of tsunami waves as they propagate unaltered in
the deep ocean. Further, they can be sited strategically so that they
are directly between tsunamigenic zones and populated coastlines.
The transmitted data can provide accurate forecasts only if the data can
be interpreted using numerical simulations of tsunamis. For this purpose,
the NOAA has developed a simulation model system called MOST, which is
capable of simulating the three distinct phases of a tsunami event - generation,
propagation and run-up over the mainland. But reliable and robust modelling
still requires an element of judgment, considerable quality control, iterative
and exploratory computations.
Mostly modellers assume that sea-surface displacement is identical to
that of the ocean bottom, but direct measurements of sea floor motion
have never been made. As a result, points out Gonzalez, even predicting
tsunami's initial height requires at least 10 parameters. Seismic data
give only the orientation of the fault plane, the quake's location, magnitude
and focus.
The rest have to be estimated. According to him, this can result in the
underestimation of coastal inundation by a factor of 10. Reliable simulations
are achieved only after repetitive runs over months. The first step towards
a reliable and robust tsunami forecasting capability is to create a database
of pre-computed scenarios that have been carefully analysed and interpreted.
From this base, a scenario that corresponds closest to the real-life situation
at hand can be picked in quick time.
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