March 14, 2011

Sendai earthquake (1)


The magnitude of 9.0 (revised) made it the biggest known earthquake to hit Japan in its recorded history.

The earthquake on Friday was preceded earlier in the week by dozens of five to seven magnitude deep-sea earthquakes in the same area, off the coast of Sendai. None of the tsunami forecasts at the time exceeded eighteen inches, and none of them reached even that height.

In this case, though, the boy cried wolf and the wolf came.

In a bitter irony, the 6.3 magnitude earthquake that hit New Zealand last month killed two-dozen Japanese students when an English school in Christchurch collapsed, until Friday the greatest loss of Japanese life from an earthquake since 2004.

The death toll is expected to at least double that of the 1995 Hanshin (Kobe) earthquake, which came to 6434. The Kobe earthquake had a magnitude of 6.8--less than several of the aftershocks--which shows how much local geology and building construction can affect the outcome.

However, the fires that broke out in the suburbs and bedroom communities of Sendai reveal a continuing problem that, together with its aging housing stock, caused the most deaths in the 1995 Kobe earthquake (and the 1923 Kanto earthquake that killed 100,000).

Even in a city like Sendai (the same approximate climate as New York City), very few houses and apartment have central heating/AC or high-pressure hot water. Instead, individual rooms are heated by portable electric, gas or kerosene space heaters.

Kitchens have a small tankless water heater over the sink and another one in the bathroom attached to the o-furo (tub). This increases the possible ignition points by an order of magnitude.

Automated cut-off technology has greatly improved in the past fifteen years, and the most serious fires this time were industrial in nature. (Though space heaters remain a major cause of accidental deaths in "normal" times.)

Failing nuclear power plants make for more dramatic headlines, though the panic in this regard has been confined to the western media. I woke up this morning to dramatic news of a second steam/hydrogen explosion--that had occurred and been dealt with twelve hours earlier.

The more ominous announcement was exposure of the number two core, the core pressure being too high to pump in water. But even this was reported in Japan with barely a raised eyebrow. Perhaps because the problem is one of latent heat, not an actively fissioning reactor.

And because, at times like this, the appropriate question to ask is: "A disaster compared to what?"

In any case, soon-to-be-retired, forty-year old technology has held up remarkably well in a real-world, worst-case scenario. It's important to remember that what modern technology does best is not produce "breakthroughs," but learn from the past and iteratively improve.

Current Boiling Water Reactor designs already address all of the major failings in the Fukushima reactors.

The only brief moment of panic I saw was a report--fairly quickly proved a false alarm--of a tsunami approaching the northern coast. Most of the power-related news yesterday was about a planned series of rolling blackouts and widespread train cancellations in Tokyo.

The greatest damage was inflicted along the coast, caused by the massive tsunami. When I was living in Odawara (left), the beach and the city were separated by a massive thirty-foot high sea wall, which also served as the foundation for a spur of the Tokaido Highway.


Sendai's outskirts (right) had no sea walls. If there was a strategy in place, it was to use the farmlands east of the city as sacrificial buffers. Fishing communities north and south of Sendai, tucked between the ocean and the mountains, were almost completely wiped out.

In the end, the death toll will depend on how well these towns were evacuated. Video has turned up of residents climbing to high ground as the tsunami poured in--not as a crashing wave, but an inexorably rising tide that just kept rising.

Even there, along the coast, reinforced concrete and steel structures are still standing--in small towns, usually the hospital and town hall and a multi-story apartment block--even after getting hit by a record-breaking earthquake and tsunami. A tribute to modern building codes.

My apartment in Osaka was a stone's throw from (well-shielded) Osaka Bay, but it was in a cluster of massive apartment buildings with sacrificial ground floors, that would spare the support beams from the full force of a tidal surge.

This suggests future infrastructure investments in breakwaters, sea walls, and perhaps the strategic placement of large, earthquake-proof structures in seaside towns. And a closer look at building codes for seaside residences, which the tsunami turned immediately into kindling.

When push comes to shove, the Japanese have never wrung their hands much over treating the environment like a bonsai tree--to be shaped and molded to suit human purposes.

Related posts

Sendai earthquake (2)
Sendai earthquake (3)
Fukushima fallout

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