Artificially induced tremors start with slow, smooth slipping
The first up-close look at artificially triggered tremors suggests seismicity caused by human activities starts slow before shaking things up. The finding could help scientists better understand, and possibly even stem, the rising rate of earthquakes near sites where unwanted fluids, such as gunky water left over from fracking, are injected underground.
Researchers triggered and studied earthquakes along a seismic fault that runs beneath a repurposed Cold War-era military base. As pumped-in water pressurized the rock, the fault slowly slid without causing any seismic activity. After a while, this slipping spawned earthquakes at spots away from the water injection site, suggesting that the quakes were only an indirect effect of the fluid injection, the researchers report in the June 12 Science.
If the newly observed slow sliding could be carefully monitored, the fluid injection rate