Lessons from tsunami

Rebuilding of affected regions of Sumatra and Aceh in Indonesia and coastal regions like Galle in Sri Lanka will be an uphill task. The recovery may be done with help from the world nations but what these regions may not recover from for a long time, however, is the psychological shock. For what happened in either Indonesia or Sri Lanka was something like a nightmare, one these regions never experienced earlier. A sense of impending catastrophe -- sudden convulsive loss of prosperity and security -- is a fear now embedded deep in the mind of the people.

"Of all the frightening things in the world, none is so frightful as an earthquake", wrote the Buddhist monk Kamono Chomei in the year 1212. People know from historical records that during the great quake of 1185 mountains crumbled and rivers were buried, the sea tilted over and immersed the land. Not a single mansion, pagoda or shrine was left whole.

Located in the intersection of Indian plate on the west, Burmese and Filipino plate in the east, Eurasian plate on the north and Australian plate on the south east, Bangladesh is a earthquake prone zone. Chittagong and its adjoining areas experienced 128 mild or moderate tremors during the last nine years. Experts opined that a 200 km continental shelf created by a long span of shallow water alluvial deposition saved Bangladesh from the recent Tsunami attack. The shelf reduced the speed of the approaching waves.

The plates in the under-sea floor of the Indian Ocean are constantly moving with the Pacific plate being the most active. Experts say two geological plates in the sea floor of the Indian ocean are constantly pressing against each other with the resultant accumulation of energy in the hard rock beneath the earth's surface. When the stored energy exceeds a tolerance limit, the resulting jolt is an earthquake causing a heavy surge of water rising upto 30 m above sea level that rips the coastal lands extending upto hundreds of miles on the coastal land taking away everything on its course with a fury of say, 500 miles/hour speed.

Located in a major fault zone, Bangladesh has hardly any reason to feel complacent. Worse, most of the land area in Bangladesh is located in a flood plain and has been built up over the last two centuries on land reclaimed from the swamps and the sea, which makes it dangerously vulnerable to tremors. The greatest fear now is the realisation that most of the densely populated cities like Dhaka and Chittagong have no regulated earthquake resistant buildings. An earthquake of this intensity in these cities, experts fear could be a calamity of unparalleled dimensions. Earthquake resisting designs have been known to structural engineers since the 1960s and the National Building Code of 1991 clearly identifies structural designs in terms of earthquakes and cyclones. "For safety's sake these guidelines should be part of the building laws", experts say.

Though the possibility of the country being devastated by a major Tsunami disaster is low, the fault lines of Chittagong, Bogra, Sylhet, Dhubri and Tripura of India may generate earthquakes at any time. If that happens, "at least 28 percent buildings of the Dhaka city would collapse in the event of 7 magnitude earthquake", BUET Professor Mehedi Ahmed Ansary, an expert in the seismic study said at a recent seminar on Tsunami held in Dhaka.

Safety laws may set the tone but public awareness and strict enforcement of codes by the authorities are essential. Most Bangladeshi homes are either designed by the owners or novice engineers or unscrupulous contractors and in most cases engineers, contractors and developers in an effort to keep their margin of profit or share high do not realise that their homes may be their tombs. Once RAJUK Chairman and now secretary of the Ministry of Housing and Public Works, Engineer Iqbaluddin Chaudhury confessed in a seminar on Tsunami that while as Chairman of RAJUK, he failed to control the corrupt practices indulged in by RAJUK officials. Iqbaluddin told the round table seminar that a section of the corrupt officials of RAJUK allow owners and developers to construct buildings with faulty designs. If that is so, we don't know what is in store for us in the event of a major earthquake in either Dhaka or Chittagong.

So how can buildings be made safe and earthquake-resistant? "Two essential factors are -- good design and good construction", says an expert. The idea is to build structures that can absorb maximum shock and still remain stable. One expert says, "If the beams and columns of the building are properly joined, 50 percent of the earthquake design is taken care of". This means if a builder has a tendency to save on concrete or steel, the sturdiness of the building is at stake. Pure geometric shapes like squares, rectangles and triangles, disperse the seismic forces equally in all directions so are safer. For similar reasons, a cantilever or irregular shape results in uneven distribution of forces causing the buildings to collapse. Uneven structures can be safe, says the expert, but they have to be appropriately reinforced.

Steel cross-beams in high-rises are the latest techniques. A solid concrete core and sheer concrete walls along with cross-beams are extremely earthquake resistant. Such structures dominate the San Francisco Skyline.

Building materials are crucial too. The safest modern building would be all steel as it is extremely good shock absorber. Cellular lightweight concrete and wood substitutes are frequently used by the quake veterans, the Japanese. Traditional bamboo and wood used in Kashmir and the Northeast India, both seismic hotbeds, are also sturdy and cause minimal damage. Glass is not earthquake friendly as a rule. However, glass can be safe -- the latest technology suggests almost invisible but strong and light-weight plastic/silicon frames to hold the glass, ensuring safety without subtracting from the aesthetics. It has to be borne in mind that an earthquake itself never kills people, it's the badly constructed buildings that do. Public awareness as well as enforcement of guidelines in construction of buildings can avert a major disaster. Delhi, the capital city of India has taken steps to make safety guidelines mandatory. California has had strict legally binding building codes in place since 1933 earthquake, with another legislation in 1992, and a more comprehensive code established in 2000.

The devastation caused by Asian Tsunami has been colossal in terms of loss of human lives and property damage. An earthquake is a hazard that gives you no warning and even no time for a journey to safety. With all our advances in science, we still can't predict an earthquake. Latur and Bhuj in Gujrat were flattened in just 45 seconds, Kobe in Japan in 20 seconds, Aceh in Indonesia and Galle in Sri Lanka were crushed in just about 60 seconds.

The Asian Tsunami disaster will remind developed nations, world leaders and all people in the world how vulnerable we really are when confronting nature. The real difficulty with sustaining a useful connection with nature comes from the fact that nature does not seek to make a connection with us. It is a hard truth to swallow but nature does not care if we live or die. One can just surmise that the natural world exists to test our capacity to care or to preserve ourselves. We have to understand that the Earth is one big natural system and that torching tropical rainforest and destroying coral reefs will eventually threaten the well being of towns and cities everywhere. However, powerful and affluent the nation-states may be nature's fury is relentless, heartless and heedless.

Our country and government because of ignorance, lack of awareness and inexperience in handling an earthquake emergency situation could never come up to that standard and performance that Japan and the U.S. have achieved. In Tokyo, emergency underground reservoirs are in place and special vehicles are ready to deliver clean water if the water mains rupture, as they did in Kobe. A computerised command centre stands ready and portable toilets have been stockpiled. Elaborate traffic plans have been made to clear streets for fire engines and ambulances. Ward offices have three-day supplies of rice, biscuits and misopaste on hand to prevent the kind of hunger that the people of Kobe suffered. In Japan individual's effort to meet such earthquake disaster is also exemplary. During Kobe quake, Diyo Okumura, 77, spent four days trapped in the wreckage of her bedroom. As it is known she always kept a snack of boiled eggs and canned fruit juice beside her bed at night. Not long after the quake, someone had heard her cries for help and told her through the rubble that she would have to wait: there weren't enough rescue workers.

The disaster plan for the country, especially Dhaka and Chittagong city should focus on stopping the fire that might engulf the densely packed localities and cause much of the death and destruction in the event of a quake of high intensity. Fire is indeed a serious threat in the old town area, where flames will be fueled by gas leaks and chemicals spilling from mom-and-pop factories. As it stands today, even with the best of preparedness which we have hardly anything worth noting, rescue vehicles would get trapped in the maze of narrow lanes. Most alarming, the city's already overburdened sewer system and water pipe might rapture polluting drinking water and unleashing diseases.

To fight such disasters, Japan has coordinated teams of engineers and doctors, fibre optic cameras to peer for survivors inside rubble, search dogs and onsite medical treatment. As it appears, our disaster management cell may not have even a bundle of chain saws and shovels, the most primitive tools needed. What we need to have like Japan and California is a stock of blankets, dry food and first aid equipment to be stored at designated parks and recreation centres. Shockingly, these densely packed cities like Dhaka and Chittagong do not have a breathing space, let alone having parks. Most important, if a building was built according to the latest building code, it would remain stable. Mentionably, Kobe city Hall and a bank building both about 15 stories high and built after the latest code kicked in 1981 withstood the brunt of the quake and remained unscathed.

With Kobe's experience, there is a grim lesson for the residents of Dhaka and other coastal districts that are built on soft alluvial soil. First, pressure released by a quake shoots water into soft sediments, liquefying them. Second, soft soils settle during the shaking generated by an earthquake. Anything on them settles, too -- violently. As it was seen, buildings near the Kobe port suffered disproportionately, those on more solid hills fared better. In some promising technique, engineers now use special steel configuration, lead shock absorbers and similar dampers to slow a structure's swaying during a quake.

The grim news could be the hardest lesson of all to absorb: no place on earth may be safe from the possibility of tectonic mayhem. More than 100,000 quakes occur each year round the globe. Experts and anxious citizens can only step up their efforts to gauge and monitor the restless plates, revamp the disaster relief plans and revise their building codes and take some comfort from knowing that Tsunamis and tremors as deadly as the recent one are still rare. If anything, this Tsunami in Asian region has brought out the best in people around the world: the inherent human spirit, strength and solidarity -- needed to combat a colossal disaster that tilted Asia and the world.

Md Asadullah Khan is a former teacher and Controller of Examinations, BUET.