By Charly SHELTON
It’s been hot, very hot, for a couple of weeks and then suddenly it gets cold. Not freezing, just cooler. Could that be – earthquake weather? Despite the fact that the weatherman refuses to put up a scene of death and destruction on the seven-day forecast in between rainy skies and a smiling sun, everyone has a vague idea of what earthquake weather is, right?
Wrong. There is no such thing as earthquake weather. This is a theory that stems all the way back to the 4th century B.C., according to the U.S. Geological Survey, when Aristotle proposed that small earthquakes were caused by pockets of wind caught in caverns beneath the surface of the earth, pushing against the roof of the cavern, and large earthquakes were caused by that air escaping to the surface. This led to the idea of earthquake weather because, when it was hot and calm, the ground would heat up and the air underneath the ground would heat and expand, causing earthquakes. The supposed earthquake weather conditions have evolved over time from hot and sunny to cold and cloudy and back again, sometimes preceded by strong winds, fireballs or meteors, depending on the teller of the legend. Even today, there is no consensus of what “earthquake weather” means to modern humans, with differing definitions from Japan to California to Oklahoma and more.
“People have anecdotally associated earthquakes with different kinds of weather; I’ve heard the stories before. But it’s generally not observed. It doesn’t appear to be true as no correlation has been found with certain kinds of weather,” said Rob Williams, geophysicist with the USGS.
There is no earthquake weather and, in fact, no way to predict earthquakes at all with any degree of certainty. The earthquake early detection system, which is planned for California in the coming years, would give as much as two minutes of warning before an earthquake strikes, not because it is predicting an earthquake but because it can detect the quake and alert the state faster than the shock waves can travel. Beyond that, Williams said, there is no real way to know.
In some locales, such as in Oklahoma over the last few years where earthquakes are related to human disposal of oil and gas wastewater deep underground, there seems to be a pattern.
“A lot of times, those earthquake sequences begin with little ones, magnitude 2s and 3s, and lead up to a magnitude 4 in the middle somewhere and then taper off,” Williams said. “But again in that situation we can’t tell when the largest earthquake in the sequence is coming; it just seems to be a little more likely that in Oklahoma small ones tend to be foreshocks for a larger event.”
California does not usually operate this way though. Geologists have dug into the San Andreas Fault at several places all the way along its length to see a record of earthquakes through the past. It seems that the big quakes happen every 120 years, but it remains to be seen if there are foreshocks to those, as they would all be within the same area and there is no current evidence of them.
“We don’t consider the San Andreas Fault to be ever in a mode where it’s not capable of producing a very large, damaging earthquake along most of its length,” Williams said. “We are further away in time from the last big one in Southern California, so we’re a little more worried down there for an impending shock. But we can’t tell if it’s going to happen tomorrow or tonight or 10 years from now.”
With no way to know when the next big quake will hit, earthquake weather or not, residents of California need to be prepared at all times for the quake to strike. For more information and to see what you can do to get earthquake ready, visit earthquake.USGS.gov.