said. She’d spent three years digging two trenches on the San Andreas that were ten feet deep and barely fifty yards long. They didn’t compare.
Elizabeth, Atkins, and a small team from the earthquake center had made the hurried trip to Millet Creek. Paul Weston had wanted to send along Stan Marshal, but had to back off when Atkins and Elizabeth refused to go if he was in the party. Weston chose not to force the issue, realizing he didn’t have a choice. They needed Elizabeth because of her expertise.
The accident with the explosive charge still nagged at Atkins. He wanted to believe it was an accident and yet it bothered him. A man with Marshal’s background and field expertise didn’t make a nearly lethal mistake like that. It just didn’t happen. He needed to think it through. So far he had only a troubling suspicion and enough lingering anger to keep Marshal as far away from him as possible.
He’d hoped Walt Jacobs would make the trip, but Jacobs had been unusually subdued since their conversation with Draper and Booker. Jacobs had begged off looking at the crevasse, saying he needed to stay at the earthquake center.
Atkins guessed there was more to it than his friend’s negative reaction to Booker’s provocative suggestion about using a nuclear explosion. Atkins wasn’t ready to take the idea seriously either. It worried him that an eminent scientist like Steve Draper seemed so interested. After the meeting with Booker, Draper had peppered all of them with pointed, often unanswerable questions. Jacobs had looked distracted, even uninterested, which wasn’t like him. Atkins figured it had to do with his wife and daughter. He still hadn’t had any word on their safety.
Elizabeth wore coveralls, leather gloves, and a hard hat equipped with a powerful spotlight. She also carried a small 35-mm camera from a strap around her neck. They were going to lower her by rope into the fissure, using the helicopter’s electric-powered hoist and air rescue seat.
Atkins didn’t want her to be down there any longer than necessary. Several mild tremors had shaken the region since their arrival and parts of the trench were showing signs of collapse. Pieces of the edge kept breaking away and falling into the chasm.
Atkins had wanted to make the descent with her, but knew he’d only get in the way.
Elizabeth planned to descend as far as possible, looking for evidence of sand blows or offsets, thin cracks in the soil, some of them no more visible than a hairline fracture. Buried in the various strata, they were telltale signs of earthquakes and her trained eye, sharpened by years of trenching in the San Andreas fault, was expert at picking them out. The recent earthquake had laid them all bare, creating a mural of the past.
She’d look for bits of carbon—fragments of leaves, peat, or twigs deposited in the soil about the time the offset or sand blows had occurred.
By radiocarbon dating these fragments, she could develop a stratigraphic map of the history of the fault’s previous earthquakes. Another Army helicopter—it was already heading their way—would take the samples to the University of Illinois at Champaign-Urbana where they could be carbon-dated. It was the closest accelerator mass spectrometer, a device that could get precise dates from even minute bits of carbon and, in so doing, date the earthquake that had produced the offsets, sand blows, and other formations Elizabeth might find.
Elizabeth didn’t need much carbon, just a few grains. The technology was based on burning the fragments and converting them to carbon dioxide. The carbon dioxide was then heated and converted to graphite. The graphite was inserted into the spectrometer, which could analyze the carbon-14 atoms in the sample and determine its age, give or take thirty years.
“I know it’s your call, but I’d recommend against this,” the crew chief said as he expertly looped a rope under Elizabeth’s arms and fashioned a bowline knot that wouldn’t slip. “This ground’s jumping. This trench could slam shut any time now.”
Atkins couldn’t have agreed more. The recent tremors had been unusually sharp. “Try to make it quick, Liz,” he said. He took her hands in his. This was a fine, brave woman. During the last few days, he’d come to realize how extraordinary she was and how much she meant to him. He wanted to talk to her. They hadn’t had many chances since the quake. Atkins sensed she felt the same way but wasn’t sure. He hoped so at least.
“Don’t press it,” he said.
“Don’t worry about that,” Elizabeth said, smiling. “I flunked rappelling when I was a Girl Scout.”
Elizabeth’s helmet was fitted with a headset microphone so she could talk with the team on the surface. She rechecked all the knots and buckles in her seat harness and signaled to the men to lower her over the side.
“Take me down ten feet,” she said. Her back to the trench, she pushed away from the wall with her feet, letting the rope glide through her fingers. She’d already picked out several places to check that were close to the surface.
In a few minutes, she shouted: “Bull’s-eye! There’s multiple scarring here. Sand boils, a big lateral offset. This might have been made by the 1811-1812 quakes.” Using a trowel, she gently scraped away at the side of the cliff. “There’s plenty of peat down here.” She put the samples into cellophane packs that she carried in a waist pouch.
Atkins hoped that would be enough, but he knew better. He heard Elizabeth say, “Let’s try another fifteen feet down.”
A helicopter crewman carefully played out more rope.
“I see some evidence of scorching,” Elizabeth said. “They may have been caused by lightning strikes that burned away some of the hillside.” She deposited a few more fragments of charcoal into her sample bag and asked to be lowered ten feet.
It was a gray, gloomy morning with a sharp wind. Not much light filtered down into the crevasse. Atkins and the others had safety ropes tied around their waists so they wouldn’t fall in if the ground suddenly gave way. From what he could see from above, the exposed wall of layered sediment would probably be measured in the thousands of years, not tens of thousands.
That was fine, he thought. They were more interested in the recent record of big quakes—those that had happened one or two thousand years before the cataclysms of the last century. That would be long enough to show a pattern—if one existed.
“It’s like a layer cake down here,” Elizabeth said. “Let out another fifteen feet.”
Playing her light on the uneven walls of the trench, Elizabeth zeroed in on another big scar, which appeared to have been made by an explosion crater.
“This sand blow… is… a… monster!” she cried out. She was down about eighty feet. The vertical offsets were even more impressive—and equally troubling. She examined two of these zigzag tears, scraping samples from each. One of them appeared to have severed an ancient streambed. The slightly coarser, darker sand might have been easy to overlook, but not for Elizabeth’s practiced eyes.
“It took a pretty good-sized quake to break through this streambed,” she said. “I’m going to do a little measuring.”
She used a steel tape measure to get the exact dimensions of the offsets, requesting several times to be raised or lowered a few feet. She also took photographs with the camera, which had an automatic flash.
“How long’s she been down?” the crew chief asked.
Atkins glanced at his watch. “Nearly forty minutes.”
“The soldier shook his head. “We’re pushing our luck.”
Atkins wanted to bring her up. Then he heard Elizabeth’s excited voice over his headset.
“Here’s another slam dunk! That offset was bigger than I thought. At least twelve meters.” Caused by the fracturing waves of an earthquake, an offset was a clear break or crack in a layer of sediment or rock.
The news startled Atkins. An offset of that size could only have been made by an exceptionally strong earthquake. It was evidence the fault had already produced several large quakes long before the triple play in 1811 -1812. The deep tear in the earth’s crust had remained dangerous for a long time.
“Liz, did you find any carbon on the offset?” he asked.
“You bet,” she said. “Some good pieces.”
A strong northerly wind stung their faces and made it feel much colder. Atkins had just put his hands in his pockets to warm them when the earth moved. A minor tremor.
“Hey, look over there!” one of the geologists shouted. About thirty yards away, a twenty-foot-long strip of earth had peeled away from the edge and fallen into the fissure.
“Elizabeth, are you all right?” Atkins said into his radio. Dust clouds were rolling out of the crevasse.
He heard her say, “Bring me up!”
