The sounds of Earth bring us some disturbing news this week.
It is an otherwise unremarkable week, replete with the usual complement of natural tectonic earthquakes from Chile and the South Pacific (listen for the beautiful whoop of seismic surface waves traversing the Earth’s crust beneath the Pacific Ocean). And we even hear a couple of minor earthquakes in Alaska. There’s nothing very unusual here; just the usual audible signs of the Earth’s formidable natural geologic processes at work.
But there is something else going on, too. Listen for the brief snap sounds at 01:10, 02:46, and 04:46. In themselves, these sounds may not seem especially ominous, but they point to a profound human-caused disruption of the Earth’s natural processes. These little snaps are minor earthquakes in Oklahoma, of magnitude just over 4. Although earthquakes in the midwestern U.S. are not uncommon, in recent years they have been occurring with increasing frequency, in direct correlation with the boom in petroleum and natural gas exploration. This recent series is believed to be directly related to the injection of wastewater from petroleum exploration projects in the area.
Oil and gas exploration is a messy and dangerous business. Hydraulic fracturing, or “fracking”, involves injecting a slurry of pressurized chemical solvents thousands of feet deep into bedrock, with the express purpose of fracturing the Earth’s crust to mobilize trapped gas and petroleum products, which may then be pumped to the surface. The toxic wastewater is then “disposed of” by injecting it back deep underground — an inherently risky process that can lubricate and reactivate ancient (and previously unknown) earthquake faults. A fault that may have lain dormant for millions of years can thus spring suddenly back to life, with unpredictable and potentially destructive results.
There is nowhere to hide from the harm we inflict on the planet. Even here in this remote and peaceful sun-dappled corner of Maine, with Oklahoma safely 1,600 miles away, we hear the cries of a troubled Earth.