“So these impermeable sediments are keeping the gas from getting out,” said Speers.
“That’s right. But, over time, we believe pressure from the underlying gas builds up.”
“Like a cork in a champagne bottle,” Decker said.
“A very big bottle,” Speers added ruefully. “As my daddy used to say: When you got gas, let it out.”
“Some scientists,” Swenson continued, ignoring him, “from both Columbia University and the Texas Institute for Geophysics speculate the rising gas might play a role in triggering collapses of the shelf. The Continental Shelf here is historically prone to landslides. An enormous slide occurred just to the south of here only sixteen to eighteen thousand years ago, at the end of the last ice age.”
“So that’s the plan then,” Speers responded. “We plant this bomb inside one of the blowout depressions, trigger it before the other tsunami gets here, and hope it knocks a chunk off the Outer Continental Shelf. Is that it?”
“That’s it,” said Swenson.
“Sounds pretty straight-forward.”
“It won’t be. We can’t just drop the bomb on the bottom and hope for the best,” said Swenson. “To make sure the gas erupts — causing a landslide — and radiates a mega-tsunami in the appropriate direction, we’ll have to navigate the Alvin as deep inside one of the dormant tunnels within the blowouts as we can.”
Speers nodded. “I’ve made more than thirty dives in the Alvin over the last six years. I was on the mission when we recovered that hydrogen bomb some knucklehead dropped onto the bottom of the Mediterranean in ’98. I’ve surveyed the Titanic and helped explore those deep-sea hydrothermal vents covered in tube worms. But I’ve never taken this DSV into a tunnel. The Submerged Operating Limits guide specifically states that Alvin — and I quote — ‘will not be operated in such a fashion so as to pass under an object, either natural or manmade… Alvin will remain clear of wreckage, debris, or natural terrain features which have entanglement or entrapment potential.’ Unquote.”
“I know,” said Swenson.
“Of course,” continued Speers. “The manual also says, ‘Alvin will remain clear of any explosives devices which may be sighted.’” He laughed. “I guess this nuclear bomb on the prow kind of blows that one, huh?”
Decker smiled. He looked over at Swenson. She appeared pale and tense in the dim lights of the submarine. A thin sheen of perspiration glazed her forehead. He had never seen her look so nervous, not even in the arms of El Aqrab. This dive was taking its toll. “Well, to keep your certification clean, you could always navigate with a blindfold,” Decker said. He laughed thinly but Swenson simply turned away and began to stare out through the view port once again.
Speers grinned back. He had a gap between his two front teeth that made him appear much younger than he was. “Look, ma. No eyes,” he said.
Swenson suddenly turned and glared at them. “Why don’t you save the macho crap for afterwards? The testosterone level in here is making me nauseous.”
“Yes, ma’am,” said Speers. Swenson looked back out through the view port. Speers glanced at Decker, rolled his eyes and shrugged. “We should be bottom-side in ten,” he said. “I’m getting a blowout, CTFM.”
“What’s that?” Decker inquired.
“Sunwest SS300 sonar. Medium range FM. It’s what we use to search and navigate the bottom. We can track negative db targets the size of a gallon gas can at six hundred feet, a zero db object like a small boulder at fifteen hundred feet, and a plus twenty-five db feature like a ridge or slope at ranges of three thousand feet or more.” He pointed to a fifteen-inch TFT flat panel. Five range rings were marked on the display. “State of the art,” he said. “We also use acoustic pingers from twenty to fifty kilohertz. If there’s a tunnel out there, we’ll see it.”
As he talked, he began to fiddle with the forward center panel. Decker watched him as he held a switch marked ENABLE in the down position. Then he pushed another switch for two more seconds. The DSV lurched forward momentarily.
“What was that?” asked Decker.
“Two of our ballast weights,” said Speers. “We’re almost on the bottom.”
Decker studied the pilot carefully. He seemed to exude confidence. He obviously knew his ship like the back of his hand. “Hey, Speers. How come you volunteered for this duty?”
Without looking up he said, “Enlisted as a SEAL ten years ago. Been in tougher spots than this one, believe me. More than twenty of us signed up for this mission. I was lucky.”
“Lucky?” said Swenson. “Is that what you call it?” She laughed bleakly.
Speers looked at her, his face absolutely serious for the first time. “I got a wife and little girl back in Virginia. I’d like to see them again, if you know what I mean.”
Swenson glanced back out through the view port. Decker nodded.
All of a sudden Swenson said, “There’s the bottom.” She seemed excited now. She pushed her face against the Plexiglas and breathed a deep sigh of relief. “The Young Canyons.” She turned toward Decker and Speers. “Listen,” she said. “About what I said before… ”
“Don’t worry about it,” Speers replied.
She smiled weakly. A little color seemed to be returning to her face. “I didn’t mean—”
“As Pilot-in-Command,” Speers interrupted, “I have the authority to terminate any dive by whatever means necessary at any time I feel a hazard to the submersible or personnel exists, without regard to mission success or completion. Unquote.” He winked at Swenson. “So unless you want to go back to the surface, just forget it.”
She nodded and stared back through the view port. “There,” she said. “Off the starboard beam.”
Speers glanced at the TFT. “I see it.”
“What?” said Decker, straining at the screen. Every inch of the sphere was covered with instrumentation: buttons and dials, lights and displays. It made the cockpit of a jet look simple. “See what?” he said.
“A tunnel,” Speers replied. “A little small but serviceable.”
Swenson turned toward Decker. “Better buckle up,” she said. “We’re going in.”
Speers piloted the DSV into the opening with uncanny skill and they began to inch their way along the tunnel. When they had gone about two hundred meters, the tunnel dropped out below them, and they followed it, descending another hundred meters into the shelf. Then the tunnel straightened out, running parallel to the surface for another two hundred meters or more before narrowing. Several times, the DSV bumped walls. At one point, the tunnel veered off in a jagged dogleg. Speers asked Swenson if this was far enough, but she shook her head. After a few minutes, they managed to squeeze through.
When they could go no further, Speers finally hit the switch and turned and said, “That’s it. We’re done. It’s just too narrow.”
Swenson scanned the instruments. “Ok,” she said. “It’ll have to do.”
For a while, none of them spoke. They knew what Speers was doing at the console — trying to plant the nuclear device in the wall. He moved the instruments with care. They watched it on the monitor. The modified Tomahawk warhead appeared much bigger than El Aqrab’s small briefcase bomb. It was shaped like an artillery shell. There was a tense moment as the release caught for a second, but Speers used one of the robotic arms to push the bomb away. It wobbled, started to fall, then finally settled on a shelf carved in the tunnel wall. Speers backed the ship up slightly before using the manipulator to arm the mechanism.