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Meditation on earthquakes

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Public Lives

Meditation on earthquakes

/ 12:34 AM October 17, 2013

Active geological faults, or fractures in the Earth’s crust that show movement over time, have been known to cause most earthquakes. Fault lines lacerate virtually all the islands that form our archipelago, Palawan being the sole exception. With the magnitude-7 earthquake that struck Bohol the other day, this beautiful island off the coast of Cebu now has two in a row in a span of two decades. The first, which occurred on Feb. 8, 1990, produced a temblor of intensity 6.8.

One wishes the energy accumulated from the straining of tectonic plates were released gradually, in small amounts. But geologists tell us this correction process that occurs in nature is difficult to predict. Thus they worry when a known major fault has not shown any activity for an extended period. Still, they cannot warn the public too loudly lest they create panic.

Nature’s time is vastly different from that which governs the routines of our daily lives.  We tend to minimize the risks posed by conditions we cannot see with our naked eyes. It is easier for the market to estimate losses in terms of profits foregone in the short term, than to assign values to the incalculable danger to which it exposes people. The human mind, says the author Gregory Bateson, must learn to find its way back to its home in Nature.

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At this writing, at least 97 people have been reported killed by the Bohol earthquake. Many more might be buried under the debris of collapsed buildings. It was astounding to see on TV so many people gathered in the streets in one of the affected small towns, watching as a large crane lifted the concrete slab of a collapsed medium-sized building to free the passengers of a van on which the slab had fallen.  What a fortunate thing, I thought to myself, that this crowd was not near this building when it crumbled. In my mind’s eye, I imagined the throng of people that gathered in Manila the previous day to receive medical assistance and bags of food from the Iglesia ni Cristo’s whole-day mission, and wondered, if the earthquake had happened in Manila, how many would have been trampled to death in the ensuing stampede. Sheer density would have changed the scale of the tragedy.

In Bateson’s classic work, “Mind and Nature,” there is a fascinating section titled “Sometimes Small is Beautiful,” in which he writes: “The elephant is afflicted with the problems of bigness; the shrew, with those of smallness. But for each, there is an optimum size. The elephant would not be better off if he were much smaller, nor would the shrew be relieved by being much bigger. We may say that each is addicted to the size that is.” In this, and in the sentence that follows, Bateson encapsulates a lesson about size that hubris, all too often, prevents us from seeing.

“There are purely physical problems of bigness or smallness, problems that affect the solar system, the bridge, and the wrist watch. But in addition to these, there are problems special to aggregates of living matter, whether these be single creatures or whole cities.”

If one is not an engineer or an architect, one can only be awed by the height of the apartment buildings that are rising in the metropolis these days, their soaring slenderness matched only by their tiny footprint. One has to marvel at the way they are able to cramp hundreds of little rabbit hutches into limited space. The plaster in which these buildings are wrapped gives them an aura of solidity that, one hopes, can withstand a magnitude-9 earthquake. But, as if to sneer at the risks, some of these structures are actually built on ground overlooking the Marikina Fault.

Bateson sounds almost as if he had these in mind when he wrote: “Problems of mechanical instability arise because, for example, the forces of gravity do not follow the same quantitative regularities as those of cohesion. A large clod of earth is easier to break by dropping it on the ground than is a small one.” Indeed, size alone may not mean anything. It is its interaction with other variables, “whose curves are discrepant,” says Bateson, that spells the difference between tolerance and change.

“For instance, gradual growth in a population, whether of automobiles or of people, has no perceptible effect upon a transportation system until suddenly the threshold of tolerance is passed and the traffic jams. The changing of one variable exposes a critical value of the other.” The problem clearly arises when the partial perspectives of individual players permit them to add more and more of a desired thing without taking into account the interaction of this growth with other factors. Let’s not even talk about the impact of these high-rise housing settlements on traffic, air quality, water supply, garbage disposal, etc. Let’s focus on how they might fare in a strong earthquake.

The big one in Bohol that destroyed the massive Spanish churches that had withstood past earthquakes across centuries must give Metro Manila’s housing developers pause. The national building code requires that these structures be able to absorb the power of an intensity-9 earthquake. The engineering provisions for such contingency are obviously complex, the more so as these buildings increase in height. But, in addition, builders must take into account the fact that an earthquake’s action can be sideways, top-down, or even wave-like.

I know that the Japanese are coming up with ever new technologies for making buildings earthquake-proof. But there are limits. For the coconut tree, Bateson observes, “the limitation of height is simply a normal part of its adaptation to a niche. The sheer mechanical instability of excessive height without compensation in girth provides its normal way of death.”

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TAGS: Bohol, cebu, earthquakes, Fault Lines, Geological Faults, natural disasters
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