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Earthquake proof structures: Japan’s 8.9 quake

With the 2011 devastation in Japan, earthquakes are once again in the news. Although more powerful, death tolls seem to be strikingly lower than in the January 12th 2010 Haiti quake where estimates of 200,000 deaths have yet to be substantiated. Had such a quake occurred in San Francisco, Los Angeles, or San Diego, no doubt the death tolls could have been in the millions.

Statistics show that most people are killed in collapsing structures. In earthquake prone areas, structures are generally built stronger to resist lateral forces from seismic shock, but because all but the most sophisticated structures are anchored rigidly to the ground, they are subject to absorb all the energy from shock waves. Only by allowing structures to slip can they become earthquake proof. Even if structures are built substantially strong enough to not collapse, if they are anchored, then damage will occur within the structure.

Fukushima Power Plant

 

Just as in unibody engineered frames for automobiles, unishell modules will be substantially stronger than conventional structures. However, it still makes no sense to subject structures to seismic shock when simple and affordable designs can protect OsumPODS from damage. Pit type slip-planes as shown in the diagram should be easy to construct and have many advantages over anchored foundations.

In costal areas where tsunamis often occur after earthquakes and cause flooding, watertight OsumPODS will be designed to float. Pit type construction will prevent structures from floating away unless flooding levels exceed buoyancy lift height (approximately 20-24 feet), which is unlikely in most cases. In costal areas prone to tsunamis and hurricanes, and other areas prone to flooding, extra precautions could be used such as building deeper pits or tethering. Other advantages of building OsumPODS to resist the forces of earthquakes will be the ability to resist damage from all types of storms. In general terms, OsumPODS will be able to survive without damage when conventionally built structures are totally demolished.

It is generally acknowledged that structures cannot be built strong enough to be considered earthquake proof. Even if structures don’t collapse in earthquakes, it is still very dangerous to be inside them due to interior furnishing and fixtures being shifted or turned over, plus shattering glass from windows. In quakes the general rule is to escape structures into the open for safety. The reverse will be true with OsumPODS, for they will be the safest place to be during any disaster.

Slip-planes will eliminate or diminish shock so that unishell superstructures will no longer require insurance, thus a lifetime of savings to the owner. Damage prevention to structures is of course only part of the problem. Conventional structures that may survive, typically loose power, water, and other services, thus rendering them useless except for shelter. Because utilities will be self-contained in OsumPODS, loss of service is not a consideration. Because OsumPODS are self-contained, produce and store all of the energy they need, filter and recirculate water, and have the capacity to produce food, autonomous sustainable communities should be quick to recover. Unishell modular superstructures will remain habitable environments even in devastating quakes and other disasters.

Also an important consideration is that there will be no need for power plants, nuclear plants the most vulnerable to catastrophic events. The meltdown at the Fukushima Dalichi power plant at Okuma, about 250 kilometers north of Tokyo is now an ongoing disaster with no solution for containing the radiation. Such an event may eventually prove to be more catastrophic than all other losses from the quake.

Fire is also a big threat from quakes due to broken gas lines. Without gas lines in autonomous sustainable communities, and because OsumPODS are 100% fireproof, loss of property and life due to fire should be totally eliminated.

Certainly there is the potential for damage and death in severe quakes no matter what precautions we take because people are out and about by foot or in transportation. Until bridges, overpasses, and other structures prone to damage or collapse are also built on slip-planes, loss of life will be unavoidable. It should also be noted that future communities built with OsumPODS will not typically have structures over three stories in height unless they can be designed to meet the more stringent criteria.

It is important to accept that devastation can bring death. If future communities build and plan for natural disasters, then whatever loss they incur should be acceptable. Investing resources in prevention should be far wiser than purchasing promissory insurance to rebuild or pay for loss of life.

With most mass infrastructure out of the equation except for roads, the potential for costly rebuilding should be diminished to acceptable levels. In future autonomous communities, even roads may be built as modular components. If modular road sections are substantially strong, even if they are moved or tipped, resetting modules should be a minor task compared to rebuilding conventional paved roads.

Because the frequency of deadly quakes is low, and often quakes occur is low populated areas, most structures built today continue to be highly susceptible to damage. We must consider as cities continue to grow, the potential for catastrophe also escalates. It is hard to predict how much devastation it will take to convince people that it makes sense to build earthquake proof structures. Eventually building code may adopt such measures, and then mandatory requirements may stifle the building industry from looking for more viable solutions.

 

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