Free Cascadia's Fault by Jerry Thompson Page A

bullies, you always know they’re not far away and could cause trouble at any moment. But for a really big fault to do nothing in all of recorded history and then suddenly rip itself apart—that was a mystery that had to be solved as quickly as possible.
    Something very much like this had happened off the coast of Chile only four years earlier, in 1960. That event too was a mystery because scientists still did not know what had caused it—the biggest temblor of all. But first, and most immediately, they had to find out exactly what had happened in Prince William Sound.

CHAPTER 4
    Against the Wind of Convention: Plafker, Benioff, and Press
    On Saturday morning, March 28, 1964, thirty-five-year-old geologist George Plafker made a hasty exit from the conference in Seattle to join a team of USGS scientists dispatched to Alaska for a rapid investigation of the earthquake. He and colleague Arthur Grantz from the main West Coast laboratory in Menlo Park, California, wanted to see first-hand what had happened to the landscape—everything from rock and mudslides to compaction of the ground, the liquefaction of soils, the heaving up or dropping down of sections of land, and the effects of tsunami waves—all before anything changed or was cleaned up. They were also hoping to find the unknown fault that had torn the land apart and clues that might explain “the mechanism” of the rupture—how and why it happened.
    Local officials in Alaska and U.S. military officers involved in the rescue and recovery effort wanted a quick damage survey that would warn them of any unfinished landslides, avalanches, or rivers that had been dammed by landslides—anything that might cause still more havoc and destruction. What they wanted to know more than anything else was whether the shaking was over yet. And if not, when might it start again?
    Within twenty-four hours of the main shock, there had already been at least ten aftershocks of magnitude 6, along with dozens of smaller but nonetheless nerve-rattling vibrations. Seismometers would eventually log twelve thousand aftershocks in the first sixty-nine days after Good Friday. But any reputable scientist knows there is no simple answer to the question of when the next tremor might come. In this case they couldn’t even say for sure what had caused the main event.
    Plafker saw some of the worst devastation right away in the bluffs around Anchorage, along Turnagain Arm and near the harbor at Fish Creek. The land underneath had liquefied, causing the surface to fracture into blocks. “There were these large areas along the bluffs that had just kind of slipped seaward,” he recalled. “They’d broken up—the blocks at the surface broke up and tilted. And there were several people killed . . . It was pretty overwhelming.”
    At the very least, Plafker and his colleagues figured they would be able to provide a detailed description of what the temblor had done to the surface of the land and which way the fault had come unstuck—assuming they could find it. What started out as a one-week reconnaissance mission to determine the scale of the thing turned into a summer-long operation requiring a whole team of USGS personnel to catalog and research the devastating aftereffects.
    They hitched rides on airplanes and helicopters borrowed from the military and flew hundreds of miles along the coast, making detailed descriptions of a torn and ravaged land, searching all the time for evidence of a major fault. The shaking had triggered a series of long, jagged rockslides that left gaping scars on the slopes of heavily forested mountains. There were open fissures and heaved-up slabs of rock in several segments along these smaller escarpments. But there was no sign of a much bigger fault—no continuous rupture in the earth’s crust, nothing obvious enough from the air to have caused an earthquake this widespread and violent.
    Hundreds of