Is August Dangerous?

Aug. 27, 2008— -- We can all rest a little easier now. The dog days of summer, or at least of August, are almost over.

Legend has it that this is an "evil time when the seas boil, wine turns sour, dogs grow mad, and all creatures become languid, causing burning fevers, hysterics and frenzies." Fortunately, that's just legend. Or is it?

The good folks who are behind the International Year of Planet Earth, a joint initiative by the United Nations (UNESCO) and the International Union of Geological Sciences, looked back through history to see if there really is anything particularly sinister about the month of August.

If their findings hold up to further scrutiny, we can thank our lucky stars, including Canis (as in dog) Major and Canis Minor, that we can soon kiss this month goodbye. At least for this year.

Here's part of what they found:

"Anniversaries marked this month include the eruption of Mount Vesuvius that buried Pompeii in 79 A.D., and the monstrous 1883 eruption of Krakatoa in Indonesia that affected Earth's climate for years afterwards. Most recently, on Aug. 25, 2005, Hurricane Katrina devastated the city of New Orleans and other areas along the U.S. Gulf Coast." The list goes on, but you get the picture.

Scientists are bringing all that to our attention now because of a super-sized earthquake drill called the Great Southern California Shake-Out, to be held Nov. 12-16. It is being billed as the largest earthquake drill in U.S. history, involving "tens of thousands of participants" in shaky southern California.

"We wanted to use this opportunity to talk about hazards in general," Linda Gundersen, chief scientist for geology at the U.S. Geological Survey in Renton, Va., said in a telephone interview.

She noted that August does seem to be a particularly bad month, at least for seasonal events like hurricanes, monsoons, floods and sultry days that can contribute to all sorts of mischief.

But she readily admits that generality doesn't necessarily apply to geological hazards.

"For earthquakes and volcanoes, it's really related to what the plate tectonics are doing at the time," she said. Weather, including the dog days of summer, is not thought to play much of a role in triggering earthquakes. But when such an event happens in August, it coincides with the enormous problems brought on by hurricanes and other seasonal disturbances, thus piling one disaster on top of another.

Scientists have made considerable progress in tracking major storm systems, thus giving us some warning when lightning is about to strike, but the geological sciences have had far less luck in predicting what lies immediately ahead.

"We're better at volcanoes" than earthquakes, Gundersen said. Most volcanoes are preceded by seismic activity and other clues that give scientists a basis for predicting when the mountain is most likely to blow. To do that, however, the volcano must be adequately instrumented, and that is not always the case.

But predicting earthquakes has humbled some of the best minds in the earth sciences. They have sharpened their ability to forecast the probability of an earthquake occurring within a specific region sometime in the next 20 to 30 years, but they haven't figured out yet how to tell us if it's going to be next week.

Historically, the right instruments have not been in place to tell what happens just before an earthquake strikes, thus revealing whatever precursors might come just ahead of the quake. One of the most disappointing experiments in recent history underlies just how difficult that is.

A few decades ago scientists discovered that one segment of California's infamous San Andreas Fault erupted at relatively precise intervals, about every 20 to 25 years. That suggested the fault should produce an earthquake of about magnitude 6 sometime in the 1980s.

Dozens of scientists rushed to the sleepy community of Parkfield, Calif., to set up their instruments in hopes of catching the earthquake in the act.

But the quake didn't come in the 1980s. Or the 1990s. When it did finally come, in 2004, those instruments provided a lot of data, but not the silver bullet that scientists had hoped to see.

"There was nothing we could tell that was predictable about the earthquake," research scientist Mike Blanpied of the geological survey said in a recorded statement. "The earth gave no indication that an earthquake was about to begin."

Scientists haven't given up, of course, but we are still a long way from predicting earthquakes, if indeed that is even possible.

One thing is reasonably certain, however. Earthquakes don't pay attention to the calendar.

So, when it comes to hazards of all sorts, is August really any worse than any other month? Well, yes and no, based on my non-scientific research. I checked the various lists of disasters in my 2005 issue of the World Almanac.

Of the 62 "noted hurricanes, typhoons, blizzards and other storms" since 1888, eight occurred in the month of August, well above the average of five for all months.

Of the 63 "notable floods, tidal waves," 12 occurred in August, way above the average of five.

But when it came to earthquakes, August was only average, with 12 out of 140.

And August was way below average for shipwrecks, tornadoes and mine disasters.

By the way, the almanac regards an event as a disaster only if the loss of human life is high. So this really isn't a scientific finding, because the largest earthquake in the world in the entire year of 2002 didn't even make the list. That 7.9 quake hit in central Alaska, in an area so sparsely populated that not a single person was seriously injured.

Fortunately, the quake struck in November. If it had hit in August, when all those motor homes are plowing along the narrow highways of Alaska, the story might have been different.

By the way, the expression "dog days of summer" has a new meaning now. It usually refers to the American stock market's slow period, when a lot of stocks become dogs.

In my business, it has an entirely different meaning. The dog days of August is a time when it seems that practically nothing is happening, so we have to dig up weird stuff to write about.