The Tsunami Tragedy


Tsunami
Waves of Fury


VIVEK S. KULKARNI, Head, Mangrove Project, reveals more
about the tsunami and the steps that can be taken to reduce
the loss of life and property by proper planning in the future.

Destination: Sumatra-Andaman Islands, off the west coast of northern Sumatra.

Date and Time: Sunday, 26 December, 2004 at 07:58:53 local time at epicentre.

Location: 3.307 north, 95.947 east.

Magnitude: 9.

Depth: 30 kilometres (18.6 miles) set by location programme.

Distances: 255 kilometres (155 miles) south-south-east of Banda Aceh, Sumatra, Indonesia; 310 kilometres (195 miles) west of Medan, Sumatra, Indonesia; 1,260 kilometres (780 miles) south-southwest of Bangkok, Thailand; 1,605 kilometres (990 miles) north-west of Jakarta, Java, Indonesia.

Location: Horizontal +/- 5.6 kilometres (3.5 miles); depth fixed by location programme.

Event ID: usslav.

This information recorded by the United States Geological Survey may not mean much to a layperson, but the horror caused by this earthquake on 26 December, 2004 will be felt for several decades.

The quake was the fourth largest since 1900 and the largest since the 1964 Prince William Sound, Alaska, earthquake. The tsunami caused by this earthquake claimed more casualties than any other in recorded history. In all, more than 2,20,272 people were killed, 22,352 are still missing and 1,076,350 were displaced in South Asia and East Africa. An estimated 1,73,981 people were killed by the earthquake and tsunami in Indonesia, 29,854 in Sri Lanka, 10,749 in India, 5,313 in Thailand, 150 in Somalia, 82 in Maldives, 68 in Malaysia, 59 in Myanmar, 10 in Tanzania, 3 in Seychelles, 2 in Bangladesh and 1 in Kenya. Tsunamis caused damage in Madagascar and Mauritius and also occurred in Mozambique, South Africa, Australia and Antarctica.

In a previous article titled "Nature's Fury"*, I had expressed my fears for the consequences Mumbai would face had such devastation occurred near the city. The tsunami that hit most of South and South-East Asia on 26/12 was worse than any of the disasters mentioned in that article. Mumbai was lucky in that only ripples of the 26/12 tsunami touched it. Scientists are still expecting a "big one" to hit Mumbai sooner or later.

The 26/12 earthquake had several aspects that were not reported by the media. Some of these aspects were:

bullet

The magnitude 9.0 earthquake at 7.58 hours at the epicentre (and in Sri Lanka) led to a sequence of 15 other quakes across the Andaman region. There have been more than 250 small, medium and large-scale tremors in the region to date.

bullet

According to a NASA report, the earth has changed its shape a little due to the earthquake and has become more spherical. This change has altered the rotation of the earth further resulting in the shortening of the days by a few microseconds.

bullet

While earthquakes cannot be predicted in advance, once the earthquake was detected, it would have been possible to give about 3 hours' notice of a potential tsunami.

bullet

Tsunamis are rarer in the Indian Ocean as the seismic activity is much less than in the Pacific. However, there are records of seven tsunamis set off by earthquakes near Indonesia, Pakistan and the Bay of Bengal.

bullet

Earthquakes occur when any of the 12 or 13 plates collide at their boundaries. The present collision is due to compression between the Indian and Burmese plates. Scientists now believe that one plate that comprised the landmass from India to Australia has broken up into two. The initial 8.9 eruption happened near the location of the meeting point of the Australian, Indian and Burmese plates. Scientists have shown that this is a region of compression as the Australian plate is rotating counter-clockwise into the Indian plate. This also means that a region of seismic activity has become active in the south-eastern Indian Ocean.

bullet

Once the large amount of pent-up energy in the compression zones of the plate boundaries have been released, it takes another build-up of energy for another event of similar magnitude. This is unlikely in the short term. However, in the future, Indian Ocean littoral regions should generate and pay attention to earthquake and tsunami warnings and be aware of the interplay of the seasonal oceanographic currents.

bullet

Had the Coastal Regulatory Zone notification not been enforced in India in 1991, the death toll would have been much higher in India.

Tsunami
Tsunami is a Japanese word which literally means tsu (harbour) nami (waves). Tsunamis are among the most terrifying natural hazards known to mankind. In the Pacific, where the majority of these waves are generated, there is greater awareness among the people. In Japan, for instance, with one of the most populated coastal regions in the world and a long history of earthquake activity, people are generally prepared for tsunamis.

Tsunamis are often mistaken for "tidal waves" when, in fact, they have nothing to do with tidal action. Tsunamis are seismic sea waves caused by earthquakes, submarine landslides, or, less frequently, by eruptions of island volcanoes. Tsunamis can also be caused by meteorite impacts or detonation of nuclear bombs in the ocean.

Characteristically, tsunamis are shallow-water waves and the ratio between water depth and the wavelength is very small. The deeper the water, the faster and shorter the wave is. For example, when the ocean is 20,000 feet deep, a tsunami travels at 550 miles per hour. At this speed, the wave can compete with a jet airplane, travelling across the ocean in less than a day.

Tsunamis in deep water can have a wavelength greater than 300 miles (500 kilometres) and a period of about an hour (the period of a wave is the time between two successive waves). Another important factor in considering tsunamis is the rate at which they lose energy. Because a wave loses energy at a rate inversely related to its wavelength, tsunamis can travel at high speeds for a long period of time and lose very little energy in the process.

Offshore and coastal features can determine the size and impact of tsunami waves. Reefs, bays, entrances to rivers, undersea features and the slope of the beach all help to modify the tsunami as it attacks the coastline. When the tsunami reaches the coast and moves inland, the water level can rise many metres. In extreme cases, the water level has risen to more than 15m (50 feet) for tsunamis of distant origin and over 30m (100 feet) for tsunami waves generated near the earthquake's epicentre.

Preparing for a tsunami
It is beyond the control of human beings to prevent natural disasters. However, it is certainly possible to reduce the repercussions, such as loss of life and property, through proper planning. Government agencies should formulate land-use regulations for a given coastal area with the tsunami risk potential in mind, particularly if such an area is known to have sustained damage in the past. Making people aware of the hazards is the key factor in tsunami preparedness. It is important that people have a technical under-standing of the phenomenon, at least at the basic level; a behavioural response stemming from that understanding; and confidence in the authorities responsible for issuing a hazard warning. Repeated false alarms may reduce the alertness and response by the community. Fortunately, forecasting of tsunamis in recent years has been quite good and the credibility of the Tsunami Warning System has improved considerably. Forecasting, however, is not an exact science as the pheno-menon itself is complex and data on which the forecast is based may often be inadequate for certain areas.

Despite modern equipment and communication means, the destruction caused by the 26/12 tsunami was massive compared to those in the past. The reason partly lies in the poor international cooperation and partly in the failure of local governments in handling such situations. Most of the countries affected by the tsunami had been struck by the fury of the sea several times in the past. Despite the damage caused earlier, most governments have over-developed the seashores, destroyed the natural protectors like mangroves, corals and other coastal ecosystems and, worse still, allowed large populations to live in the danger zone.

International Tsunami Warning System (TWS)
The massive destruction caused by the May 1960 Chilean tsunami prompted a large number of countries to join the TWS. Another catastrophic tsunami generated by the Alaskan earthquake of 1964 emphasized the need for an International TWS. Functioning of this system begins with the detection by any participating seismic observatory of an earthquake of sufficient size to trigger the alarms, set at the threshold of 6.5 on the Richter scale. The Pacific Tsunami Warning Center collects the seismic data, locates the earthquake and computes its magnitude. When reports from tide stations show that a tsunami has been generated which poses a threat to the population in any part of the Pacific, a warning is transmitted to the dissemination agencies for relaying to the public. The agencies then implement predetermined plans to evacuate people from endangered areas. In addition to the International TWS, a number of Regional Warning Systems have been established to warn the population in areas where tsunami frequency is high.

Tsunami and Coastal Ecosystems
In 2002, Naluvedapathy in Vedaranyam district, Tamil Nadu state, planted 80,244 saplings to enter the Guinness Book of World Records. Little did they realise at the time that the trees would save their lives. When the tsunami roared into the coast on 26/12 many villages and towns were crushed as the giant waves swept across open beaches. But the people of this village remained almost unscathed.

Unlike other coastal areas in Tamil Nadu, Naluvedapathy is shielded by tree cover that is nearly a kilometre deep. Casuarina, coconut and other varieties of trees have turned the place into a mini-forest. Compared to the adjoining town of Nagapattanam, where more than 3,500 people died, Naluvedapathy suffered meagre losses.

It is unfortunate that we have been rather slow in understanding and using our coastlines wisely. The words "ecology" and "economy" are both derived from the Greek word "oikos" meaning home or surrounding. Yet, both the words are
given different meanings with economy meaning "progress" and ecology meaning "deterrent" to progress. The economists have outnumbered and segregated the ecologists, who are generally identified as a bunch of troublemakers!

The catastrophe of December 26 was the outcome of poor planning, faulty business and economics. Shrimp cultivation, rising to over 8 billion tonnes a year in the year 2000, has already played havoc with fragile ecosystems. Asian countries are producing shrimps for western countries, but at a heavy price to their environment. Shrimp farms are constructed by destroying mangroves. The farm operates for three to five years and is then abandoned. The abandoned farm then remains a useless piece of land. Thousands of hectares of land are destroyed throughout Asia in this fashion.

Some recorded tsunamis in India:

Date

Location

1524
1762

1819
1847
1881
1883
1941
1945
 

Near Dabhol, Maharashtra
West Bengal and Orissa due to quake at Arakan Coast, Myanmar
West coast of India due to quake at Rann of Kutch, Gujarat
Great Nicobar Island
Car Nicobar Island
On the east coast, due to Krakatoa eruption
On the east coast due to eruptions at Andaman Islands
On the west coast of India including Mumbai due to a quake at Merkan Coast, Baluchistan

Each acre of mangrove forest destroyed results in an estimated 676-pound loss in marine harvest. Mangrove swamps have been nature's protection for the coastal regions from large waves and cyclones, and serve as nurseries for three-fourths of the commercial fish species that spend part of their life cycle in the swamps. But mangroves are one of the world's most threatened habitats and faulty economic policies have only hastened their destruction.

It has been established now that mangroves provide double protection the front mangroves like red mangroves, with their flexible branches and tangled roots hanging in the coastal waters, absorb the first shock impact of the waves. The second layer of tall back mangroves then operates like a wall withstanding much of the sea's fury. Mangroves in addition, absorb more carbon dioxide per unit area than ocean phytoplankton, a critical factor in global warming. Mangroves also absorb large amounts of water during heavy rains and prevent high tide water from getting on the land, thus acting as flood controllers.

In India, mangrove cover has been reduced to less than a third in the past three decades. Between 1963 and 1977, India destroyed nearly 50 per cent of its mangroves. Local communities were forcibly evicted to make way for the shrimp farms. In Andhra Pradesh, more than 50,000 people were forcibly removed and millions displaced throughout the country to make room for the aquaculture farms. Whatever remained of the mangroves were cut down by the hotel and tourism industry.

In 1960, a tsunami wave hit the coast of Bangladesh Sunderbans, an area where mangroves were intact. There was no damage reported either of loss of life or property. The mangroves were subsequently cut down and replaced with shrimp farms. In 1991, thousands of people were killed when a tsunami of the same magnitude hit the same region. The Chidambaram town and Muthupet, with dense mangroves, suffered low human casualties and less economic damage from the 26/12 tsunami.

The staggering social and economic loss of the December 2004 tsunami will take some time to be ascertained. World governments have so far pledged $4 billion in aid. This does not include the billions being spent by relief agencies. The World Bank is considering boosting the aid packet to $1.5 billion. In addition, the World Food Programme (WFP) plans to feed some 2 million survivors for the next six months. The feeding operation is likely to cost $180 million. All this could have been avoided had the planners, the economists and the social scientists used our coasts wisely.

Mangroves of Pirojshanagar
Amidst the story of terror, apathy and ignorance there is good news for the residents of Pirojshanagar the stability of the environment. The protection provided by the solid wall of mangroves is sufficient to ward off the insurgence of giant waves. The mangroves of Pirojshanagar are not protected because of any legal compliance but as a social commitment. The very act of formalising the mangrove project as part of Godrej's environmental policy has given the project credibility. The Thane Creek has recently been included in the Important Bird Areas of India. The achievements in the fields of mangrove conservation and spreading awareness are increasing in numbers and scope. But a lot remains to be done. We see the mangrove project as an independent self-sustaining project that would not only attract thousands of visitors but also act as a reputed organisation with complete expertise in mangrove management and coastal stabilisation from the ecological point of view.

The number of calls received by us after the tsunami disaster and the kind of queries coming from organisations and government bodies throughout the country strengthen the fact that our efforts are getting noticed even as our commitments are getting deeper. In the near future, we will be getting involved with various organisations in efforts to reduce the impact of the waves of fury on our coastlines.


An Egret seen at the Pirojshanagar mangroves, a haven for birds.

REFERENCES:

  1. Murty, T.S., "Storm surges meteorological ocean tides", Bulletin of the Fisheries Research Board of Canada, Ottawa, 1984.

  2. Pacheco, Javier F., and Sykes, Lynn R., "Seismic moment catalog of large shallow earthquakes, 1900 to 1989", Bulletin of the Seismological Society of America, Vol. 82, No. 3, p. 1306-1349, 1992.

  3. Dasgupta, S., Pande, P., Ganguly, D., Iqbal, Z., Sanyal, K., Venkatraman, N.V., Dasgupta, S., Sural, B., Harendranath, L., Mazumdar, K., Sanyal, S., Roy, K., Das, L.K., Misra, P.S., Gupta, H., "Seismotectonic Atlas of India and its Environs", Geological Survey of India, 2000.

  4. Tandon, A.N., and Srivastava, H.N., "Earthquake occurrence in India: Earthquake Engineering", Sarita Prakashan, Jai Krishna, Vol. 1-48, Meerut, 1974.

  5. Times of India newspaper archives (Mumbai), India

  6. "Mangroves as Coastal Protection from waves in the Tong King Delta, Vietnam", Yoshihiro Mazda, Michimasa Magi, Motohiko Kogo and Pham Nguyen Hong, Mangroves & Salt Marshes, 1997.

  7. Lareef Zubair, "Earthquake and Tsunami", Sri Lanka Meteorology, Oceanography and Hydrology Network and The Earth Institute at Columbia University.

  8. "Distribution of shortening between the Indian and Australian plates in the central Indian Ocean", James Van Orman, James R. Cochran, Jeffrey K. Weissel and Florence Jestin.

*Please see CHANGE November-December, 2004


The year 2004 has come to an end
A memorable year it has been.
Ups and downs and highs and lows
In the past year we have seen.
The year went by smoothly
But came to a crashing end.
Nature's fury shattered the life of so many
Broken pieces we are still to mend.
Tsunami a huge tidal wave
Swept over the life of all.
Nature's wrath spared none
Mankind suffered a great fall.
Thousands of homes were destroyed
Thousands of lives were taken.
We have taken nature for granted
And a heavy price we have forsaken.

 
  The aftershocks of the disaster
We are still enduring.
The ones alive are being given help
Their pains we are curing.
In the history of mankind
This blemish will remain forever.
When reminded of this grave calamity
The world will always shiver.
The wounds will take time to heal
This disaster will always remain in our mind.
But we will stand up with a smile
And walk ahead leaving this terror behind.

Ashwathi Thampi
J.K. Singhania School (Standard VIII)
Thane

Ashwathi is the daughter of Ajitkumar (Appliance Division) and Prema Thampi (Prima Division).

 

One of the many paintings on the tsunami by our Udayachal Primary School students. This one is by Kavya Bhat, Standard IV (Teacher: Anita D. Sequeira)

 

 

Top