The Scarred Earth

SUBMERGED: Part of the Indonesian city of Banda Aceh, on the northern tip of the island of Sumatra, was wiped away, as seen in these satellite images before the tsunami (top) and after (bottom).

A year of death and destruction wreaked mostly by humans ended with nature flexing her own muscles, to terrifying effect. A section of the earth's crust hundreds of kilometers long tore off its moorings, slamming into the seawater above. The resulting tsunami traveled at 700 kilometers per hour to rear up like a hydra onto shores, sweeping away some 225,000 lives and millions of livelihoods across 12 nations. Now, as broken-hearted survivors turn to piecing together the remnants, scientists are scrutinizing the oceanic and island terrain to determine how the crust has changed and to gauge what further horrors the earth may have in store.

The magnitude 9.0 earthquake was the largest ever recorded in the region and the world's biggest since a 1964 Alaskan quake. The underground tear started 100 kilometers off the coast of Sumatra, on the western edge of the Burma plate.

This "sliver" plate, a long, thin section of crust that reaches southward from Myanmar (Burma), pushes over and against the India plate to its west at the rate of 14 millimeters a year; on December 26, 2004, the Burma plate jerked westward and upward along an incline by perhaps 15 meters.

According to an early reconstruction by seismologist Chen Ji of the California Institute of Technology, the earthquake initially displaced 400 kilometers of crust 20 kilometers below the seabed. The tear very likely continued farther north but too slowly to generate seismic waves. (Long ruptures produce very low frequency seismic waves that are difficult to measure and interpret.) "Our preliminary tsunami modeling indicates the length of the rupture was significantly larger than the estimates the seismologists are putting up," remarks Frank Gonzalez of the National Oceanic and Atmospheric Administration in Seattle. In any case, the earthquake shook the bottom of the sea along a ridge aligned north to south, sending upraised walls of water barreling mainly east and west.

On reaching gently sloping coastlines the tsunami slowed down, shoaled and rose many meters to descend on unsuspecting humans. It first bulldozed coastal towns in Sumatra and, farther north, washed clean over several of the Nicobar Islands, leaving in places only a handful of survivors clinging to treetops. Sloshing within the confines of the Andaman Sea to the east, it carried off vacationers in Thailand. The westward wave traveled across the Indian Ocean as swiftly as a jet plane, striking India and Sri Lanka. Six hours later it claimed lives on Africa's shores and kept on going until it had circled the globe and dissipated.

At the same time the tsunami scoured the planet, the earthquake permanently altered its shape. Because the plates pulled tight and snug over one another, the earth's crust became more compact. Calculations suggest that, like an ice skater drawing in her arms, the contraction made the planet rotate faster, by perhaps three microseconds. And because the ocean bottom near the epicenter thrust upward, the planet's water now has less room, causing the sea level to rise by about a millimeter.

More locally, the earthquake and its aftershocks changed the shape and orientation of virtually the entire Burma plate and the lands it supports--in particular, the Andaman and Nicobar islands. The two island groups are the peaks of an undersea mountain range, raised by the scraping up of soft sediments as the plate's leading edge pressed down and forward against the India plate.

After the earthquake, some of the Nicobar Islands seem to have sunk, and one island, Trinkat, has split into three pieces, with fish now swimming around once idyllic, palm-fringed villages.

The western edge of the Burma plate has risen a few meters--exposing coral beds around the tiny island of North Sentinel--whereas the eastern edge has dropped.

According to Survey of India, a government mapping department, the main town in the Andaman-Nicobar region, Port Blair, has shifted by a meter and sunk by 25 centimeters. Such tilting is to be expected, notes Joseph Curray of the Scripps Institution of Oceanography in La Jolla, Calif.: one undersea ridge south of the Nicobars was once, he suspects, a piece of Sumatra that sunk in the distant past. "Sooner or later Banda Aceh will subside" and disappear into the ocean, he concludes of the Sumatran city.

"Sooner" for a geologist usually means "later" for other humans: the earthquake and its aftershocks, Curray believes, eventually ruptured and released stress along the entire western edge of the Burma plate, making other massive jolts unlikely for a century. Large quakes could still be expected along the eastern edge, he warns: the Burma plate, drifting northward around 25 millimeters a year, tends to stick and unstick against the plate to its east in motions that produce "strike-slip" earthquakes. Such earthquakes probably would not result in tsunamis, because they would cause the water column above mainly to shear, not to lift. But Kerry Sieh of Caltech suspects that an increased risk of a tsunami-spawning earthquake prevails south of the epicenter, where the rupture did not propagate. Sensitive measurements of the region's contours will be necessary to resolve this question.

Seismometers, tide gauges and other detection instruments now being deployed will make the next tsunami, if not the next earthquake, come as less of a surprise. Still, the coastal areas of Asia face future challenges: cyclones and their attendant surges will take an increasing toll as global warming disturbs weather systems.

The devastated communities should ideally be rebuilt on high ground far from shore, where they would be protected by mangroves from the ever rising ocean. But for millions of the poor in crowded countries, such safety may never be possible.

Source: Scientific American

By Madhusree Mukerjee

The assassination of Kennedy
An unsolved riddle

John F Kennedy, the 35th president of United States of America was unequivocally one of the most dynamic American leaders. He promoted the civil rights of the black Americans in the early Sixties and contributed to rearrange the US civil administration. It's undeniably unfortunate for history that this magnanimous president was assassinated in Dallas, Texas on 22 November 1963. He was fatally shot down by the assassin while riding in a motorcade through downtown Dallas alongside his wife Jacqueline Kennedy.

Shortly after the assassination Dallas Police arrested 24-year-old Lee Harvey Oswald from the Texas Theatre as a suspect. Later the cops alleged that Oswald alone had shot the president from the sixth floor of the 'Dallas School Book Depository Building' situated at the Dealey Plaza. However, Oswald denied the charges. Subsequently, another man named Jack Ruby, who had connections with Dallas Mafia, killed Oswald in police custody. The investigators asserted that Oswald was a pro-Castro activist and he was fascinated by communism, which ultimately led him to kill the American president. But the reality behind the assassination was still hidden behind an obscure smokescreen.

A few years later prominent lawyer and District Attorney (New Orleans) Jim Garrison opened the case and underlined serious flaws in the report of the initial investigation of the case by the Warren Commission. Warren Commission's report had stated that, Oswald was the sole gunman and neither the sniper nor his killer "was part of any conspiracy, domestic or foreign, to assassinate President Kennedy," But Garrison argued that in reality it was a well-planned conspiracy where the motive of the real perpetrators was something deeper. It was estimated that Oswald was a part of a deliberate conspiracy involving either CIA agents angered over Kennedy's handling of the 'Bay of Pigs fiasco' or members of Mafia seeking revenge for Attorney General Bobby Kennedy's formidable criminal investigations. It was also speculated that Kennedy had been killed because of his decision to withdraw the US troops from Vietnam and because he had attempted to establish a better relationship with the communist USSR. JFK reduced the power of CIA and restrained the surreptitious activities under CIA covert operations. This made him unfavorable to certain influential people at the higher level of the system. Jim Garrison's report highlighted the controversial possibility that there had been more than one gunman involved in the assassination. He interpreted the circumstances and revealed the possibility that Oswald had been duped by the real conspirators. By presenting substantial evidences and acoustic analysis he suggested the fact that only one assassin couldn't have murdered JFK with such precision and that he had probably been killed by a 'triangulation of crossfire'.

In the light of his accusation an alleged CIA agent named Clay Shaw was arrested and tried. But he was acquitted because of the lack of crucial evidence against him. The assassination of JFK is still an unsolved mystery. It's an issue of irreversible controversy, speculation and bafflement. Although investigators and historians have tried to solve the riddle, it's still unclear who really killed President Kennedy. However, there's absolutely no doubt about the fact that this brilliant president contributed enormously to the prompt development of USA. After his assassination vice-president Lyndon B Johnson took his place. Some historians believe, if JFK had not been assassinated, America might well have turned its attention from Vietnam. There is no doubt that he was one of the greatest American leaders ever. Although there are rumors about his involvement with Mafia and an alleged affair with Marilyn Monroe, it's undeniable that he was an authentic dreamer.

Renowned director Oliver Stone (the director of 'Born on The Fourth of July') has made the movie 'JFK' which exquisitely depicts the process of investigation by Jim Garrison and his endeavors to reach the real truth (Kevin Costner starring as Jim Garrison). The movie also portrays the historical background of the Kennedy assassination.

By KH. ASEF SAFA KABIR

Precious little girls…

I always wonder how it's like to be a brother to a sister. What love and friendship do they share between them? Well I'll probably never know, because I don't have a sister. My parents are also pretty discontented about this.

In our country, it's more common to see parents wishing for sons, for a number of reasons. My parents, however, only tried to have a daughter.

Somehow, that wish remained just a wish. They did have a daughter, the very first one and they were very happy about it. I don't know who was green-eyed about my parents' happiness, but my sister died after four months leaving a very sad scenario behind her. Both my parents blamed themselves.

After recovering somewhat from their grief, they tried again, and my eldest brother was born. I heard stories about how they kept spending their nights looking at him after he arrived.

One after another, four babies followed, myself included, and each time, they hoped that it will be a girl. Alas! God Almighty seems to have had other plans. I was the last, and after that, they realised they would probably never get their wish, and sadly resigned to their fates, although sometimes I feel that they still regret.

As for me it was an unexplained thing. Just before I started writing this, I saw a brother and a sister duo - the best and most ideal situation in the world from my perspective. I was in a local hotel at the evening eating some puris, when I saw the two little sibs. The boy was about ten years old and the girl was about eight years old. They entered the hotel and ordered some bhuna boot. I think their budget was not as high as they ordered one plate for both of them, and the miserly hotel boy probably realised this. He gave them just one tablespoon of the stuff. What surprised me was they were happy about what they got, even though I could see they were being cheated.

The boy gave his sister the first taste. Watching them, I felt this odd pang deep inside of me.

Maybe that's why I'm writing this, and it was surprising too. You see these things in films and movies, but how many times does one notice it in real life? Let me remind you they both were very young.

It turned out that the boot bhuna was too spicy for the two kids. Mouths afire, they looked around for some water. I offered them my glass. The boy gave his sister the first sip, even though he was also suffering. It left me wondering.

Am I feeling this way because I don't know what it's like to have a sister? It's something I would have liked very badly to experience. So to those lucky fellows who have sisters my request to them is, "Please try to cherish your sister".

They say, "When you have it you don't see it, but when you don't then you will feel it." I guess I'm the perfect example of that.

By Rajin Ahmed