Steam erupted from a fissure on the near side of the thermal area, less than fifty feet from the foot of the slope below the trail. A thick, white cloud wafted away from the jet of superheated water spewing from the black crust.
The rumbling faded away, and the jet of steam subsided. A third vibration did not come. Chuck pressed a palm to the hillside. Nothing.
“Kowabunga,” Randall said from where he sat in the middle of the trail. “Dude!”
“What the hell was that?” Rosie asked.
“Rosie!” Janelle exclaimed.
“Chuck says it all the time.”
Carmelita shook a finger at her sister. “‘Heck. You’re supposed to say heck.”
Rosie wrapped her arms around her torso, her hands gripping her sides. “I will if Chuck will.”
Chuck felt Janelle’s eyes on him. “Heck it is,” he said.
Rosie asked Lex, “What the heck was that? Was it an earthquake?”
“That’s exactly what it was,” Lex said.
“Like in the movies? Holy shlamolies.”
“They’re to be expected, of course. Yellowstone is one of the most active seismic zones on the planet.”
Janelle said, “You don’t sound too worried.”
“Big quakes are rare here—that is, in human time. But small quakes of the sort we just felt have been occurring in the park more and more frequently the last couple of years. The Geology Team is looking into what’s causing them.”
“And their hypothesis at this point?” Chuck asked, anticipating the answer.
“Hydraulic fracturing around the park perimeter.”
Chuck told the girls, “That’s where companies pump water and chemicals into the ground to release oil trapped in layers of rock. There was a bunch of that kind of drilling during the last natural-gas boom. Now, the drilled wells are producing—that is, sucking the gas out of the ground.” He asked Lex, “Could the tremors be causing temperature fluctuations in the thermal basins?”
“At this point,” Lex replied, “I’d say it’s logical to assume the mini-quakes and temperature fluctuations and hydraulic fracturing are related. But, like I said, that’s what the Geology Team is studying.”
“I read that plain old, everyday earthquakes—with no hydraulic fracturing involved—tilted Yellowstone Lake back and forth over and over in the past, so it drained down one side of the Continental Divide, then the other.”
“Millions of years ago, yes. But there’s no way fracking could set off an earthquake that big today.”
“I thought that’s what the Geology Team is trying to determine.”
Lex averted his eyes. “Since the oil companies started working around here,” he admitted, “they’ve written lots of checks to the park—for research, infrastructure upgrades, you name it. It’s hard to point a finger at them with no proof.”
“Spoken like a true bureaucrat.”
Lex grunted. “Which is exactly what I am.”
Clarence’s stud earrings sparkled in the sunlight as he shook his head. “Hombre. Here we are in one of the most remote places in North America, and we’ve got manmade global warming melting the glaciers and manmade earthquakes messing with the geysers. It’s like the start of the apocalypse or something.”
“I wouldn’t go that far,” Lex said. “But humans certainly can alter things far from where their activities take place, Yellowstone included. More and more, the questions researchers are studying in the park revolve around what can be done to control, or at least minimize, the effects of those activities.” He pushed himself to his feet. “Two miles to camp,” he said to the hikers. “Shall we?”
They strode along the open hillside and into the trees, leaving the thermal area and smell of sulfur behind.
Rosie looked up at Chuck as they walked through the forest. “Is an earthquake going to come and swallow us up?”
“It’ll take a lot more than a teeny, tiny tremor like that one to get us.”
She nodded to herself. “So the grizzly bears will get us first.”
“Rosie!” Janelle said.
“I think your mom’s going to get you before an earthquake or a grizzly has the chance,” said Chuck.
The trail wound in and out of the pines as it descended the east side of the valley. It was late afternoon by the time everyone left the last stand of trees and topped the hill overlooking camp. Above the hikers’ cheerful chatter, the walkie-talkie clipped to Lex’s belt beeped, signaling an incoming call. A cry rose from the foot of the slope. Chuck looked down toward the cabin, where a figure was heading up the trail toward them, waving and shouting.