Bits and Pieces

Sunday, December 26, 2004

Sumatran Earthquake/Tsunami Kills Thousands (Updated)

There's nothing much to report on the latest news that you can't get more reliably from the news. All I can do is fall back on my education and give a quick refresher course in physical geography. I hate to sound ghoulish, but I studied earthquakes and tsunamis for four years at university so this is fascinating to me. Ironic, though, that the largest earthquake during my lifetime is overshadowed by a secondary effect of it.

It occurs to me that the general public learn much of what they know about tsunamis from Hollywood movies like The Day After Tomorrow - movies that tend to sacrifice fact for spectacular effects. I'm no expert, but I might as well use my soapbox to straighten out a few facts.

To begin, the tsunamis were a symptom of an earthquake measuring 8.9 on the Richter scale. To give you some sort of idea of the power released during a quake of this magnitude, it's equal to about 32 billion tons of TNT. As residents of LA will be aware, the Richter scale is a base-10 logarithmic scale, which meane that an earthquake measuring 9.0 on the scale will release many times more energy than an 8.0 quake.

The quake occurred just off the south coast of the Indonesian island of Sumatra, where the Eurasian and Indo-Australian tectonic plates meet. Those of you who have a firm grasp of plate tectonics can skip over the next paragraph, but for the rest of you...

As you probably know, the surface of the earth is made up numerous sections known as tectonic plates. These plates effectively float on the dense, hot asthenosphere, a layer of the mantle in which the rock is hot enough to become pliable - to be able to deform without fracturing.

Now, these tectonic plates move incredibly slowly - usually less than a few centimetres every year, and it's where they meet each other that we get problems. The Eurasian plate and the Indo-Australian plate meet each other at Sumatra. The Indo-Australian plate is being forced underneath the denser Eurasian plate at a rate of about 6cm each year at the Java Trench (here is a simplified animation of the process). The movements of the two plates are what cause earthquakes. The stresses caused by the two plates scraping together force pressure to build in the rock until it discharges all at once, literally snapping. The faultline slips perhaps 10-15m, causing the displacement of huge volumes of water. 15 metres doesn't sound like much, but you have to realise that this is 15 metres movement over maybe 1,000km of plate margin.

The displaced sea water travels at speeds of up to 500mph, effectively invisible to the naked eye. The crest of the waves will only be a few feet high in open water, the only visible sign of the enormous volume of water speeding along under the surface.

The momentum of the waves means that they can travel vast distances with little loss of energy. The 1960 earthquake off the coast of Chile created a tsunami that had enough energy to travel 10,000 miles in 22 hours until it hit land in Japan, killing about 150 people. Update - the Sumatran tsunami has now crossed almost 3,000 miles of ocean, killing at least 9 people in Somalia.

As the waves approach land, and the sea floor rises, the water slows dramatically as the waves compress like an accordion, forcing them to pile up vertically. They draw water from the coastline, creating powerful undercurrents that can drag swimmers out to sea. The tsunamis don't break like normal waves, but simply hit the coast like walls of water, destroying buildings, tossing boats into the air like toys, and smothering those who have been unable to escape under unimaginable volumes of water.

It's folly to think of a tsunami as just a large wave. It's much more accurate to imagine that it is an extension of the sea, conquering the land and pushing back the coastline, in some cases by hundreds of metres. The 1993 tsunami at Okushiri, Japan reached 32m in height - the same as an 8-storey building. You can't hide from that, and you sure as hell can't try to swim to the surface. All you can do is run.

Some of us have a head start. I wrote my dissertation on the gap in preparedness and aid for earthquakes between the developed and developing world and, tragically, most of the nations affected by today's disaster have laughable warning systems. It's been several years since I've looked into the subject but, last time I looked, India's method of saving lives following tsunamis was to build refuges on stilts. Their warning system consisted of rusting air raid sirens from WW2. I hope they've improved in the last 5 years, but I wouldn't bet on it.

The Pacific, in comparison, is relatively well-prepared for tsunamis. Underwater sensors can alert us to approaching tsunamis, giving people living on the Pacific Rim adequate time to find high ground or flee inland. Unfortunately, such systems are not widely used in the Indian Ocean and Bay of Bengal due to the cost of installing and monitoring the sensors, and the relative rarity of tsunamis.

Reuters now has the death toll at over 6,300. I'm gonna throw out an educated guess final figure of at the very least 8,000 - factoring in the death tolls of islands (the Maldives, for example) and areas whose communications have been cut off or are otherwise unable to collate reliable death tolls. India will continue to climb, but Sri Lanka will finish as the big loser for this one. NB - the prediction includes only those killed in the immediate aftermath of the disaster. Considering the damage to infrastructure - lack of clean water most being the most pressing concern - the final death toll will easily exceed 10,000. It'll be days before the aid effort is at full speed, and weeks before those displaced will be able to move out of Red Cross shanties. True to the Christmas spirit, a tsunami is the gift that just keeps on giving.

While you watch the news, remember this - the death tolls they're reporting are only government and NGO estimates. There's no way of knowing what the final toll will be. Perhaps the most horrifying thing is that there are few reports from Aceh province of Sumatra, the closest land to the epicentre. This is probably due to the fact that lines of communication have been cut, but it could easily be the case that the towns of the western coast, or at least the people who live there, just don't exist anymore.

I'm waiting from reports from Bangladesh. The energy of the sea funneled into the Ganges Delta may have caused the river to break its banks. At the very least, the silty Delta will be flooded. At worst, 141 million people living on a flood plain the size of Iowa will be without potable water or edible crops.

For news of the disaster as it emerges, The Command Post is running excellent coverage here, a first-hand account here, updated death tolls here and how you can help.

Update - When I predicted a death toll of 8,000 around 6 hours ago I thought I was being pessimistic. After watching the news all day I'll upgrade that prediction to at least 12,000 - and possibly as much as 15,000 - deaths caused by the immediate effects of the tsunamis. Thousands of fishermen went out on the early morning tide into the Bay of Bengal, and are now floating back to shore. The final death toll in the coming weeks is anyone's guess. Michele notices the first outlet reporting 10,000+ deaths.

'Nother Update - Even my ridiculously pessimistic prediction seems to be being caught up by reality. Including the thousands still missing, the immediate death toll should easily top 15,000. It may climb as high as 20,000. As evidenced by my own failed attempts to predict the number of casualties, it's just impossible to make an educated guess when so many nations, including thousands of secluded islands, have been affected. Hell, the waves have killed people thousands of miles away in Africa. The updated death toll of Aceh Province in Sumatra has outstripped even my own predictions, and I consider myself fairly knowledgable on natural disasters.

But the worst is yet to come. Everyone lives near the coast in this part of the world. Economies are driven by two things - tourists and fish. The infrastructure of the islands of Indonesia fringes the islands. Roads, utility lines, shops and houses hug the coast for dear life. With this infrastructure in tatters the islands will starve in darkness, but not before they die of thirst.

The Asian nations surrounding the Bay of Bengal will suffer differently, but much worse. Fresh water sources will be tainted by the poisonous sea. Crops will be flooded, and food stores destroyed. India, Sri Lanka, Burma and Bangladesh will fall to disease. It's vitally important now to make sure that aid organisations get in with food, water and medical supplies.

Doctors speak of the golden hour, the vital period following a serious injury during which the victim must receive medical attention to survive. This is the golden hour for Asia. The doctors need to get in. The Red Cross need to arrange shelters. Fresh, clean water has to flow. Without that, a death toll of 15,000 will seem like pocket change.

'Nother Update - I give up making predictions. Sky News has it at 23,000, and it's still rising.

Go here to find ways you can help. has emailed me the address of an emergency message board for the friends and families of people teaching English around Asia. The address has been forwarded to all 27,000 TEFL members, so if you haven't heard from a friend or relative go here. Maybe someone who knows them wil be able to help.

'Nother Update - OK, I'm pretty pissed off right now. I'd intended to upload my dissertation - The Effects of National Wealth on Aid Distributions Following Earthquake Events - as a preamble to a post about how emergency aid is so laughably inadequate, but I can't find it for the life of me. I was sure the bound final draft was in a file at the foot of my bed, but all I can find is a sketchy first draft with every second letter crossed out in red pen with the comments 'Wrong!', 'must improve research' and 'this is crap'. Damn. That took a year to write and now it's probably rotting under a sofa in some rubbish tip.

'Nother, 'nother Update - Joe Gandelman has a good roundup of eye-witness accounts from Asian bloggers. Just like the in days following 9-11, the Ukranian elections and every other regional event of the past few years, the blogosphere has given us a view of events as they occur free from the dribble of information released by Reuters and the AP.
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