Monday, August 20, 2007

Infrastructure Decimated By Earthquake In Kobe, Japan On January 17, 1995

On January 17th, 1995 a massive earthquake hit the region of Kobe, Japan. This quake was unique in that it occurred at the intersection of three tectonic plates. This resulted in enormous damage to the area. Buildings collapsed, roads were destroyed, and utilities went offline for days.

An earthquake will cause damage in two ways. Initially damage is caused as a direct effect of the shift in the tectonic plates. In this incident the shifting plates resulted in ground displacements as large as 3 meters along the fault line. Fortunately the actual fault line did not go through the heart of the port city of Kobe. In this case the direct effect damage was limited to the destruction of underground utility lines, fences, and drainage ditches. The rapid shift in displacement of the ground along the fault line sheared the underground lines like butter, cutting off all major utilities.

Most of the damage caused in this earthquake was the result of the secondary effects of the quake which radiated out from the epicenter. Secondary effects from a quake of this magnitude may take many forms including aftershocks, liquefaction, fissuring, and possibly triggering additional quakes. Wooden houses collapsed from the severe shaking of the ground. Many buildings suffered extensive damage from the 5th floor and higher. This was attributed to the building codes at the time that relaxed the structural requirements of the buildings from the 5th floor up.

The social impact of this quake was devastating. The Japanese had considered themselves to be well prepared for such an event. It was thought that their buildings, mostly made of wood, were better able to withstand the shaking and shearing forces brought on by quakes because of the material's ability to flex, and bend. What they did not count on was the effect that the heavy tiled roofs would have on their structures. The heavy weight of the roof, placed on the lighter wood frame created a whiplash effect that turned these wooden structures into rubble. Making matters worse was the fact that roads where damaged, and those that where not damaged were covered in debris. The rubble strewn everywhere made it very hard to navigate into the area and render assistance, resulting in a much longer and more difficult recovery period. In all, 5000 people died as a result of this disaster.

The economic effects of this earthquake where just as devastating. The clean-up and repair of all the damage cost millions of dollars. Local businesses, even those not located directly in the areas of major destruction, where unable to resume business, as local utilities had suffered major damage and remained offline. In some cases it took as much as 2 months to effect repairs.

The Japanese thought they where prepared for any eventuality. They built their homes and buildings using techniques and materials that they thought would withstand the forces that an earthquake would create. Yet, despite all their preparation and planning, the result was still a disaster of colossal magnitude. Some 5000 people lost their lives; buildings, houses, roads, highways, and all major services where damaged, and tremendous financial loss, and hardship resulted. There is no such thing as being too prepared.

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