Sinking feeling: Quicksand can swallow cities


Q. Earthquakes have been known to rubble a city in seconds. Has quicksand ever swallowed a metropolis whole? ­L. O. Arabia

A. The two in fact can work together, as happened when a 1964 earthquake in Japan produced wholesale liquefaction of a sandy area in the city of Niigata, causing apartment blocks to subside and fall over, while remaining more or less intact, says Roger Suthren, geologist at Oxford Brookes University, Headington, Oxford, United Kingdom.

Long ago, a couple of Egyptian cities were apparently built on unstable, wet ground on the Nile delta, and eventually slid out to sea, as described by New Scientist magazine. "Their remains were discovered recently offshore," says Suthren.

Liquefaction occurs when water-saturated sandy soil near the ground surface is shaken and temporarily acts like quicksand. Together with landslides, this is a common secondary earthquake hazard, reports "Business Wire."

To observe the process in miniature, suggests environmental fluid dynamicist David Pritchard of the University of Cambridge, England, fill a jar half full of water and half of fine sand, seal and let the mix set to firmness. Now open, and gently "seat" a few coins on the surface; then bang the side of the glass with a knife. The vibration (earthquake) will sink the coins (cities).

Q. Looking at the restaurant menu, you note many prices ending in "99." Where are you? Next place you stop, the prices more often end in "00." Later– maybe a lot later– you see menu prices ending with an "8," never a "9" or a "4." That's odd. Where in the world are you now? ­P. T. Fogg

A. Price endings of "99" are called "odd-pricing," or "just below pricing," commonly used in North America to connote price-discounting or bargain items, says Ohio State University hospitality management professor H. G. Parsa.

So in the first instance you'd likely be at a fast-food (quick-service) restaurant, then at your next stop a full-service family restaurant or an institutional dining setting. Consumers associate prices ending in "00" or "55" with quality, and "99" with value, says Parsa. These effects can be deliberate or subtle, influencing choice of restaurant or item selections.

Europeans and Asians mostly don't odd-price on their menus. The Chinese have for centuries been prohibited from using "9" endings, a number reserved for the emperor, says Parsa. Instead, many prices there end in "8," the next highest digit. They also don't use "4," considered an unlucky number. For this last stop, then, you may well have boarded a jet to dine far, far from home.

Q. If we humans have been evolving for millions of years, why aren't we perfect by now? When will we be? ­E. Post

A. Natural selection cannot produce perfection, with us, seals, peacocks, anything, say Neil Campbell and Jane Reece in Biology:

Reason #1. What went before limits what can happen now. Nature cannot scrap ancestral anatomy and start anew, but must adapt using longstanding forms. For example, our common, excruciating back problems result in part from the incompatibility of the human upright posture imposed on an anatomy of four-legged ancestors.

#2. Each organism must do many varied things, such as seals sunning themselves on rocks where flippers make for terrible locomotion, then swimming with those marvelously adapted paddles. Human hands and limbs too are a wonder of versatility and athleticism, but by the same token are prone to sprains, torn ligaments, dislocations.

#3. Chance affects the gene pool more than was once believed, such as winds blowing insects to another place, and not just those best suited to the new environment.

#4. Even if the fittest survive to pass on their genes, "they are only better-than specimens, not the ideal best."

On the other hand, culture can be perfected– work on it!

Send Strange questions to brothers Bill and Rich at