Cascadia's Fault - Jerry Thompson [126]
At the end of September, when the long-awaited Parkfield event finally happened, there was no immediate payoff because, as even Bakun and Lindh admitted, the new equipment did not detect any obvious precursors. But the drilling continued, enthusiasm undimmed. The next phase of the SAFOD project would deploy the oil industry’s newest directional-drilling technology to turn the bit almost sideways and then drill through the fault—from the Pacific plate eastward—until it penetrated the gap and reached relatively undisturbed rock in the North America plate on the eastern side of the San Andreas. The plan was to bring up core samples of rocks and fluids to find any secret ingredient that might cause ruptures to begin.
The project would also implant more instruments inside the active zone to make long-term measurements of small to moderate tremors and continuous measurements of rock deformation as it built up during the next cycle. Nothing on this scale had ever been tried. These were ambitious goals: dig down to the very heart of an active fault and watch it rupture from the inside.
SAFOD was only one of three components of an even grander science project called EarthScope, which set out to monitor plate tectonic movement along the entire U.S. west coast and create a 3D seismic image of the basement of North America. The Plate Boundary Observatory would do on a continental scale what SAFOD was doing close up on the San Andreas. The USArray—a spiderweb of new seismometers spun across the lower 48—would probe thousands of miles down to study the forces that create and shape the earth’s crust from the bottom up.
To me it sounded like NASA gone underground. In fact, when I rang geophysicist and project director Greg van der Vink in Washington for some background, he volunteered his own analogy that EarthScope was geology’s equivalent of a lunar landing, “the biggest thing we’ve ever done.” But with a $200 million construction and installation budget for the first five years, EarthScope was really more like NASA on a crash diet, although it was still an impressive undertaking. And it would eventually become the Plate Boundary Observatory’s job to focus a sharp new lens on Cascadia’s fault.
With satellite technology that could measure plate movements down to half a centimeter, the system was intended to cover the western edge of North America from Mexico to Alaska with receivers spaced roughly 125 miles (200 km) apart. If the funding held out there would eventually be 875 permanent GPS stations working in concert with 175 deep borehole strainmeters 650 feet (200 m) underground to measure “at the proton level” what satellites cannot see from space. On standby would be another pool of a hundred portable GPS receivers for temporary deployment and rapid response to volcanic and tectonic emergencies.
Although EarthScope’s budget looked flush by Canadian standards, it had taken van der Vink and others a long time to convince Washington politicians to spend money on something as optically unsexy as geology. Officials at the National Science Foundation insisted the money be spent in the United States. If Mexico and Canada wanted to join the project they would have to pay for their own equipment.
After the Rogers and Dragert findings were published in Science, however, news about episodic tremor and slip spread quickly. Greg van der Vink told me that ETS was “the poster child” for EarthScope science, exactly the kind of thing they were meant to study and “one of the most exciting new discoveries in a long time.” As the implications sank in—here was a major fault sending some kind of mysterious signal every fourteen months like a giant metronome—the Cascadia Subduction Zone suddenly became a higher priority.
When Herb Dragert heard about the Plate Boundary