Cascadia's Fault - Jerry Thompson [67]
Linda Munroe came away with a scoop. Readers of The Oregonian were informed that, in Yeats’ words, “Oregon, as well as the rest of the Pacific Northwest, is indeed Earthquake Country! None of us felt as safe after that day as we thought we had been the day before.” Oregon had joined the club with California, Alaska, Chile, and the rest.
Before leaving Monmouth, John Adams asked if he could take a first-hand look at those turbidite samples in the core lab on the Oregon State campus in nearby Corvallis. Up to that point he had only read the published reports. What he found when he studied the actual mud cores and data logs apparently strengthened his conviction that a very large series of seismic shocks was the only logical explanation for so many landslides happening simultaneously so far apart along the continental margin. He returned to Ottawa and went to work on a new paper that would put the turbidites front and center as physical evidence of past ruptures on Cascadia’s fault.
Brian Atwater, meantime, received word in March 1987 that the final draft of his buried-peat story had been accepted at Science. After his talk at Monmouth, excitement about what he’d found at Neah Bay and points south quickly spread. Gary Carver of Humboldt State, who had come to the conference to report his evidence of active thrust faults along the coast of northern California, was one of those impressed by Atwater’s presentation at Monmouth.
“I saw it for the first time and it made sense,” Carver told me. “So when I came home from that meeting, I flew into the airport there at Humboldt and instead of home, I drove out to the Mad River slough on the north end of Humboldt Bay and walked. The tide was out and I walked onto the tide flat and leaned over the tide channel and reached down there and scraped the bank with my hand and saw the buried peats that were identical to the ones that Brian had been working on. My first thought was—oh, this is part of the subduction zone! That was an awakening moment.” Carver chuckled.
He and colleague Bud Burke quickly found and mapped more of the same: layers of peat buried under gray bay mud, some with layers of tsunami sand and the same kinds of buried stumps and forest debris that Atwater had discovered up north. Seven buried marshes would soon be found at Netarts Bay, along Oregon’s north coast, by geologists Curt Peterson and Mark Darienzo. As many as eight more would soon be found in and around Coos Bay in southern Oregon by Alan Nelson of the USGS and his colleagues. Up in Canada evidence for ten possible tsunamis would be found at the head of the Alberni Inlet on Vancouver Island by John Clague of Simon Fraser University and Peter Bobrowsky of the British Columbia Geological Survey.
While Atwater’s 1987 buried-peat paper was still being readied for publication, Tom Heaton saw a preliminary draft and decided to cite the breakthrough in a review article he and Stephen Hartzell, of the USGS, were writing to underline the similarities between Cascadia and other deadly subduction zones. The work begun with Hiroo Kanamori continued with an update in Science that in turn got picked up by Walter Sullivan of the New York Times.
Sullivan’s distillation of this carefully worded warning from one of America’s top research labs produced a story with the power to shock any who paid even scant attention. For probably the first time in a nationwide mass-circulation newspaper, the threat posed by Cascadia’s fault was given the same kind of serious and sobering treatment as the San Andreas. The opening line was among the least inflammatory yet nonetheless cautionary proclamations written about seismic mayhem.
“Analysis of the geology along the coasts of Washington and Oregon has raised the possibility of an earthquake there as severe as any recorded elsewhere in this century,” Sullivan wrote.