The staggering destruction wrought by last week's earthquake in Japan, the full scope of which is yet to be determined, recalls other disasters from Japan's history. The Great Kant? earthquake of 1923, which measured a magnitude 7.9, killed more than 100,000 people and devastated Tokyo. Frank Lloyd Wright's then recently completed Imperial Hotel (above) sustained substantial damage, but was among the few buildings in Tokyo left standing after the quake and ensuing fire. Water from the decorative pools lining the courtyard was used to quell fires in the surrounding buildings; extra steel in the frame prevented a roof collapse. In the aftermath, one of the hotel's principal investors sent a telegram to Wright exclaiming: "Hotel stands undamaged as monument to your genius. Congratulations." That wasn't quite true, in fact, as several floors buckled and stonework fell from the facade, but after Wright passed the telegram to reporters, the story stuck. That perceived success earned Wright a reputation as a stout builder, but by 1968 the fundamental failings of the Imperial Hotel structure led to its demolition. Principal among its shortcomings was a shallow foundation set on loose wet soil, which Wright designed to float on the mud "like a battleship floats on salt water" in the event of an earthquake. Instead, the foundation sank irrecoverably into the silt, but that doesn't mean lessons weren't learned from the Imperial Hotel's successes and failures.
In 1981, the Japanese government revised the building codes for new construction to include provisions to alleviate the effects of an earthquake. The new requirements called for rubber dampers, hydraulic shock absorbers, and "base isolation pads," designed using the same "battleship" principle that Wright presumed would protect the Imperial from earthquake. The base isolation pads allow the structure to remain upright while the ground shifts laterally underneath (above). In 1995, the 6.8 magnitude Kobe earthquake struck, claiming 6,000 lives. Though tragic, this death toll was a marked improvement over the 1923 quake, despite drastically increased population density, in part thanks to the improved building techniques.
Still, traditional wood-frame housing and buildings built prior to 1981 fared poorly in the '95 Kobe disaster. Traditional wood-frame houses (above) in the area of the quake were built with heavy tile roofs over wood construction to ward off the heavy winds and rain of Pacific typhoons. During the Kobe earthquake, however, those massively heavy roofs overwhelmed the weakened frames, causing many to collapse. Again, the Japanese improved their building practices, mandating thicker walls and lighter roofs, sacrificing typhoon-resistance for earthquake safety. Wright's Imperial Hotel, with it's steel-reinforced construction, avoided such a fate, while retaining the tile roof. It would be many years before this technology would be feasible for residential building on a wide scale.
Friday's magnitude 9.0 earthquake was more than 180 times stronger than the Kobe earthquake and generated a 33-foot tsunami that overwhelmed the substantial defense systems in place on the coast (video, above), causing massive flooding, sweeping away entire villages, and knocking out the backup diesel generators at the Fukushima nuclear plant, a situation that remains only tenuously under control. This sort of devastating flooding—a destructive force that never tested the Imperial—will be the next challenge for Japanese engineers, architects, and urban planners as the island nation rebuilds its infrastructure, and attempts to sturdy itself against future disasters.
· Frank Lloyd Wright [Google Books]
· Advanced Earthquake Resistant Design Techniques [University at Buffalo]
· Building codes spared Tokyo from wider destruction [ABC News - Australia]
· Tsunami wave crashes over seawall (VIDEO) [YouTube]