Controlling What We Can

Earlier in the week we had an earthquake which was felt by many, a rarity in these parts.  It measured 3.8 on the Richter.  I felt it roll through, lasting about three seconds.  The house creaked, though the epicenter was 100 miles away.  The tremor was reported in communities around Chicago, some 150 miles distant.  It occurred within the Wabash Valley Fault System found in SW Indiana and SE Illinois.  Geologists have documented activity at the site stretching back 20,000 years, some events being as strong as 7.5 magnitude or greater.  

To the southwest of the Wabash Valley lies the New Madrid Fault, the one responsible for a massive earthquake in the early 1800’s.  Its damage spread over 130,000 square miles and its impact felt over nearly 3 million miles. The quake caused areas to be permanently uplifted while others sank. Reelfoot lake, a beautiful, cypress flecked shallow wetland in northwest Tennessee, was created by the earthquake and the Mississippi River flowed backwards for days to fill it.  Eyewitness accounts describe sounds of distant thunder, “but more hoarse and vibrating… (and periodic) saturation of the atmosphere with sulphurous vapor, causing total darkness.”  The quake hit in mid December, and aftershocks, some stronger than the initial quake, went on for nearly two months.  Geysers of sand and water shot tens of feet into the sky from opened fissures, lakes became dry land and dry land became lakes.  For weeks “the earth was in continual agitation, visibly waving as a gentle sea.”

Unlike other natural events, earthquakes are hard to predict.  We can see, with radar, an approaching hurricane, and have some level of confidence when a tornado might spawn.  Advance notice usually accompanies wildfires and we are forewarned of an impending volcano.  But earthquakes are different, and to date the best science can offer only probabilities, say “a ten percent chance over the next 50 years.”

History holds one exception to this fact and it involves the great Shawnee chief, Tecumseh.  Prior to the New Madrid quake, he was traveling widely, gathering support for a Native American confederacy to resist the expansion of white settlers that had moved onto Native American territory. He told the tribes he would stomp his foot and send a tremor across the land as a signal to initiate an allied attack against the whites.  To the tribes unwilling to join, he warned of a tremor that would shake their teepees to the ground.  The New Madrid quake followed soon thereafter, and with it came the question: Did Tecumseh predict the event, or cause it?

The great state of California, where minor earthquakes are nearly as common as progressive ideas, there has been a lot of attention given to earthquake preparedness, and the effort is reflected in such things as building codes, evacuation routes, and emergency response planning.  In the Midwest, geologists and insurance companies are aware of the threat and first responders entertain what if scenarios, but there appears a lesser concern among Midwesterners at large, perhaps because we don’t feel the tremors that routinely occur, though there are many.  We tend to think the greater risk lies out west while the probability is relatively high under our feet and the potential impacts greater due to regional geology.  From a geologic and historic perspective, a Midwest major event is probable sometime in the next 50 years.

If it was within our ability to prevent earthquakes, would we do it?  Our population densities and infrastructure development virtually assures apocalyptic conditions when the next big one hits.  There are things we can control and things we cannot.  Hurricanes, twisters, droughts, floods, heat waves, and wildfires are our most familiar natural disasters.  If we could make changes in our society and use existing technologies to reduce the frequency and intensity of these, would we?  

There were heavy rains and flooding down south yesterday, and more precipitation to come.  The west is drying up, with megadrought declarations over large portions.   Megadroughts have endings but scientists say this one may not, but instead mark the beginning of permanent aridification of the west.  Reservoirs have reached historic lows.  Water supply to millions is threatened. It’s hot.  Really hot.  Blackouts are forecasted as electricity demand soars, and wildfire season, which has steadily lengthened and worsened over the years, is predicted to be extreme.

Natural disasters happen.  We expect them to be explosive and dramatic but not all are.  Mass extinctions, a critical loss of biodiversity, sea level rise, permanent desertification of entire regions, a continuing loss of topsoil, might have insidious origins but are now blatant and dire. They are occurring not naturally, but unnaturally, due to our influence on the planet.

Earlier in the week we had an earthquake which was felt by many, a rarity in these parts.  It was a minor tremor, a tickle, and most who felt it were thrilled by the experience.   Had it been twice the size it would have wreaked havoc.  It was small, but perhaps enough to jar our memory holes, enough to open our eyes to the unnatural disasters we are bringing on ourselves.