I live in an earthquake zone, bordering the southern portion of the San Andreas fault at a distance of roughly 150 miles. My portion of the Pacific “Ring of Fire” has been disturbingly quiet for the last 300+ years. Basically, ever since major civilized development of this area, there has been an increased demand for water (a somewhat scarce resource when living in a desert). They’ve been diverting Sierra Nevada run-off through the Owens Valley for decades, and they had to, because the aquifers are all dried up.
Right now, big news around the US is that Oklahoma has had thousands of 3.0 earthquakes this year, largely because of the byproduct of natural gas extraction deep beneath the earth’s surface. They somehow get gas out of rock by injecting water in there, way down underneath the surface. This, in turn, lubricates otherwise dormant faults in the deep continental portion of the North American plate, and: boom, earthquakes. So they’ve been literally rocked by quakes this year because of natural gas “fracking.”
No water means, no earthquakes. Right?
But the pacific plate is constantly moving. It’s pushing northwest all the time, subducting under the Aleutian Islands and East Asia, and sliding by the bump on the North American plate. A feat which has been made more difficult by a total lack of groundwater to lubricate the fault system. So tension is just, building. A little bit more every day… but constantly pressing, grinding, crushing. We still have earthquakes, but tiny ones, and lots of them, all along the fault zone. But nothing big that would account for all the accumulated tension.
What’s going to happen? To hell if I know. I’m not an earthquake expert… I just know what they know… the processes that are actually happening underground are somewhat fact. We know the plate is moving, we know the “bump” in the plate boundary right at the Garibaldi fault is creating a lot of friction and preventing easy movement across the length of the terminator, and that it hasn’t moved enough to release the tension in over 300 years.
Easter Sunday 2010, a 7.2 occurred near the plate boundary, but well south of the border and had very little implications. I was actually VISITING San Diego that very weekend from northern California, and I happened to be in Descanso, a good 100 miles from the epicenter, and BOY did we still get some serious shaking. Cars were moving side to side, people hunkered down and running out of their homes. Crazy shit. That was the largest quake I had ever been involved in… and we haven’t had a measurable earthquake since.
Bum, bum… BUM!