People living along the San Andreas Fault in California—and, for that matter, people living very far away from it—have long kept a wary eye out for any sort of seismic activity, always anticipating The Big One. It turns out they may have been waiting for the wrong thing. There is definitely something going on here, but seismologists aren’t quite sure why it’s happening or what it means.
Just as we’ve always expected of the famous fault line, the earth is moving. This isn’t a rapid seismic event, though, but more like a very slow ooze. Near the Salton Sea, which marks one end of the fault, a muddy spring formed about a decade ago. It gave off a faint smell of sulfur, and while scientists didn’t think it represented any new seismic activity itself, they said it might be caused by gases from deep underground escaping through cracks caused by previous earthquakes. Then in 2015 the spring began slowly moving; as this article notes, it traveled 60 feet over the course of several months, then 60 feet in a single day. It’s now about 240 feet from where it started out years ago.
Still, you might say, that’s not a lot of distance, so what’s the big deal? It’s headed straight for Union Pacific’s railroad tracks, as well as a highway, an oil pipeline, and a bunch of fiber optic cable. In areas where it has traveled it leaves a sunken trail, and the ground there is unstable. Geologists say the process is similar to the formation of a sinkhole, with underground liquid eroding and undermining the surface soil.
Union Pacific has built temporary tracks to avoid the moving phenomenon, and Caltrans has planned detours in case it has to shut down portions of Highway 111, which is a major corridor between Interstate 10 and the US-Mexico border.
The couple of attempts so far to stop or divert the ooze have failed. Imperial County officials tried draining off water from the spring, and Union Pacific built a wall of rocks and steel, 100 feet wide and extending 75 feet below the surface, to protect the railroad tracks. The spring traveled underneath the wall and continued on its way, undeterred.
Have you witnessed sinkholes or other unexpected occurrences in your area?
StormCon Call for Speakers Deadline is December 5
StormCon, the conference exclusively for stormwater and surface-water professionals, is seeking abstracts for presentation at StormCon 2019, which will take place in Atlanta, GA, on August 18–22, 2019. The deadline for submitting abstracts is Wednesday, December 5, 2018.We are accepting abstracts in six conference tracks: Stormwater Infrastructure and Best Management Practices; Green Infrastructure; Stormwater Permit Compliance; Funding, Staffing, and Managing the Stormwater Program; Industrial Stormwater Management; and Research and Testing. For descriptions of the tracks and more information about submitting an abstract, please visit www.StormCon.com.