Cascadia's Fault - Jerry Thompson [48]
PART 2
SETBACKS AND BREAKTHROUGHS
CHAPTER 9
Mud Cores and Lasers: The Search for Evidence
At five o’clock in the morning it was still pitch black out on deck and the heavy air promised another sticky day. The boatswain, a muscular young guy in his mid-thirties with a patchy beard and a sunburned face, instinctively stepped back to get clear of the bight of steel cable at his feet.
He glanced up behind the blue-green glare of the floodlights to make eye contact with the winch operator in a glass booth on the upper deck, then raised his right arm and made a circling motion, fingers pointed upward at the sky. The diesel roared a little louder, the cable drum began to turn, and a heavy metal shaft rose from the shadows.
A handful of scientists gathered along the starboard rail for a final inspection of their strikingly low-tech research probe—a “Benthos gravity corer.” To the unfamiliar observer, it looked like nothing more than a hollow, vertical steel tube, about ten feet long and four inches in diameter (3 m by 10 cm), fitted at the top with a collar of five lead weights shaped like doughnuts and capped off with a set of angular fins, the kind you used to see on bombs, designed to make the rig fall through the water straight and true. Gravity would soon take it to the briny deeps, where it would stab the sea floor and try to capture nearly ten thousand years of tectonic history.
The scientists, a mixed team of marine geologists, oceanographers, graduate students, and veteran researchers from the United States, Britain, Spain, Belgium, Germany, Japan, and Indonesia, had crossed the Andaman Sea aboard the Roger Revelle, a research ship operated by the Scripps Institution of Oceanography. They had sailed from Phuket, Thailand, on Monday afternoon, May 7, 2007, slipping between the Nicobar Islands and the northern tip of Sumatra into the Indian Ocean. Just before sunrise on Wednesday they were about to drop their first probe into the ocean mud west of Banda Aceh, that unfortunate beachfront town so memorably wrecked by the earthquake and tsunami of December 26, 2004.
I had met U.S. chief scientist Chris Goldfinger, a marine geologist from Oregon State University (OSU), a year earlier in 2006 while filming an update to my original 1985 Cascadia documentary. He and his team had been punching core samples out of the sea floor and then adapting a technique used by oilfield geologists to match up the stratified layers of clay, silt, and sand at various points along the rupture zone for clues about the size and timing of past earthquakes. In the spring of 2007, he and an international team of scientists went to sea off Indonesia to find out what the latest event—the magnitude 9.2 Sumatra–Andaman megathrust—might tell them about seismic patterns in Cascadia.
In the ship’s lounge the previous afternoon, he had gathered the graduate students, postdoctoral researchers, and coring technicians for an introductory briefing. Looking more like a veteran California surfer than a labcoated investigator, Goldfinger clicked his mouse and the first image appeared on a roll-up screen: a 3D cutaway view of the sea floor off the Oregon coast. “So here’s what Cascadia looks like in cross-section,” said Goldfinger. “Just a very simplified image of the accretionary wedge and the forearc structure.”
I had seen this seafloor display at his office in Corvallis several months prior to the voyage and thought of it as a magical mystery tour of a place I’ll never get to visit in person. Cascadia’s undersea topography (bathymetry is the correct term) was a hidden landscape, another whole world, exotic yet oddly familiar. The same rugged terrain you see above ground along the Oregon coast exists in a parallel universe on the ocean floor.
This deep-sea world had its own substantial hills and valleys, its own cliffs and steep canyons, and what looked like sharply cut river channels running across a wide, flat