The fiber-optic cables that travel underground, along the seafloor and into our homes have potential besides transmitting videos, emails and tweets. These signals can also record ground vibrations as small as a nanometer anywhere the cable touches the ground. This unintended use for fiber-optic cables was discovered decades ago and has had limited use in military and commercial applications. A University of Washington pilot project is exploring the use of fiber-optic sensing for seismology, glaciology, and even urban monitoring. 

When the next major earthquake hits the Pacific Northwest, a system launched last spring should give some advance warning, as emergency alerts go out and cell phones buzz. But how well the system functions might depend on whether that quake is the so-called “really big one,” and where it starts. The Pacific Northwest’s last magnitude-9 event from the offshore subduction zone was in 1700.