Treasure of Khan

sailing north. It appeared to be some sort of research vessel, with an old-style helicopter wedged on the stern deck. The rotors on the helicopter were sweeping in an arc, as if preparing to take off. Scanning above the bridge, she noted oddly that the ship's mast appeared to be flying both a Russian and an American flag. Likely a joint scientific study, she mused. Reading up on Lake Baikal, she was surprised to learn of the West's scientific interest in the picturesque lake and its unique flora and fauna.

Geophysicists, microbiologists, and environmental scientists migrated from around the world to study the lake and its pure waters.

'Back on line,' Roy's voice shouted across the deck. Twenty minutes later, they reached the southern edge of the bay, completing their multilane sweep. Theresa determined that there were three lake bed structures seen with the sonar that would warrant further examination.

'That wraps it up for the opening act of today's program,' Wofford said. 'Where to next?'

'We will cross the lake to a position here,' Tatiana said, tapping the map with a slender finger.

'Thirty-five kilometers southeast of our current position.'

'Might as well leave the sonar in the water. I don't think this boat can go much faster than our survey speed anyway, and we'll get a look at the water depths as we cross over,' Theresa said.

'No problem,' Wofford said, taking a seat on the deck and stretching his legs up onto the side railing.

As he casually watched the sonar monitor, a quizzical expression suddenly appeared on his face. 'That's odd,' he muttered.

Roy leaned over and studied the monitor. The shadowy image of the lake bottom had abruptly gone haywire, replaced by a barrage of spiked lines running back and forth across the monitor.

'Towfish bouncing off the bottom?' he asked.

'No,' Wofford replied, checking the depth. 'She's riding forty meters above the lake floor.'

The interference continued for several more seconds, then, as abruptly as it started, it suddenly ceased.

The contours of the lake bottom again rolled down the screen in clear imagery.

'Maybe one of those giant sturgeon tried to take a bite out of our towfish,' Wofford joked, relieved that the equipment was working properly again. But his words were followed by a low, deep rumble that echoed across the water.

Far longer and lower pitched than a clap of thunder, the sound had an odd muffled quality to it. For nearly half a minute, the strange murmur echoed across the lake. All eyes on the boat scanned north in the direction of the noise, but no visible source was evident.

'Some sort of construction?' Theresa asked, searching for an answer.

'Maybe,' Roy replied. 'It's a long ways off, though.'

Glancing at the sonar monitor, he noticed a brief spate of noise that minimally disrupted the image before a clean contour of the lake bed reappeared.

'Whatever it is,' Wofford grimaced, 'I just wish it would stop messing with our equipment.'

-2-

Ten miles to the north, Rudi Gunn walked onto the bridge wing of the gray-hulled Russian research vessel Vereshchagin and looked up at the azure sky overhead. Removing a thick pair of horn- rimmed glasses, he carefully cleaned the lenses and then peered upward again. Shaking his head, he walked back onto the bridge and muttered, 'Sounds like thunder, but there's hardly a cloud in the sky.'

A hearty laugh erupted at his words, flowing from a portly man with black hair and matching beard. Dr.

Alexander Sarghov resembled a circus bear, his large frame softened by a jovial demeanor and warm ebony eyes that twinkled with life. The geophysicist from the Russian Academy of Sciences Limnological Institute enjoyed a good laugh, especially if it was at the expense of his newfound American friends.

'You Westerners are very amusing,' he chuckled in a heavily accented voice.

'Alexander, you'll have to excuse Rudi,' answered a warm, deep voice from the opposite side of the bridge. 'He's never lived in an earthquake zone.'

The green opaline eyes of Dirk Pitt sparkled with mirth as he helped heckle his deputy. The head of the National Underwater and Marine Agency stood up from a bank of video monitors and stretched his six-foot-three frame, his palms scraping against the deckhead. Though more than two decades of undersea adventures had exacted a toll on his rugged body, he still had a lean and fit form. Just a few more wrinkles around the eyes and a growing tussle of gray at the temples indicated a wavering battle with age.

'An earthquake?' Gunn speculated. The brainy deputy director of NUMA, an Annapolis graduate and former Navy commander, stared out the bridge in wonder.

'I've only been in one or two, but those were felt and not heard.'

'Puny ones just rattled the dishes, but larger quakes can sound like a string of locomotives running by,'

Pitt said.

'There is a great deal of tectonic activity under Lake Baikal,' Sarghov added. 'Earthquakes occur frequently in this region.'

'Personally, I can do without them,' Gunn said sheepishly, retaining his seat by the monitor bank. 'I hope they don't disrupt our data collection of the lake's currents.'

The Vereshchagin was engaged in a joint Russian-American scientific survey of Lake Baikal's uncharted current flows. Not one to stay confined in NUMA's Washington headquarters, Pitt was leading a small team from the government research agency in collaboration with local scientists from the Limnological Institute at Irkutsk. The Russians provided the ship and crew, while the Americans provided high-tech sonobuoys and monitoring equipment which would be used to paint a three-dimensional image of the lake and its currents. The great depth of Lake Baikal was known to create unique water-circulation patterns that often behaved unpredictably. Tales of swirling vortexes and fishing boats getting pulled underwater by their nets were common stories among the local lakeside communities.

Starting at the northern tip of the lake, the scientific team had deployed dozens of tiny sensors, packaged in orange colored pods that were ballasted to drift at varying depths. Constantly measuring temperature, pressure, and position, the pods relayed the data instantaneously to a series of large underwater transponders that were positioned in fixed locations. Computers onboard the Vereshchagin processed the data from the transponders, displaying the results in 3-D graphic images. Gunn glanced at a bank of the monitors in front of his seat, then focused on one in particular, which depicted the midsection of the lake. The image resembled a pack of orange marbles floating in a bowl of blue ice cream. Nearly in unison, a vertical string of the orange balls suddenly jumped rapidly toward the top edge of the screen.

'Whoa! Either one of our transponders is going tilt or there's a significant disturbance at the bottom of the lake,' he blurted.

Pitt and Sarghov turned and studied the monitor, watching as a flood of orange dots raced toward the surface.

'The current is uplifting, at a dramatic rate,' Sarghov said with a raised brow. 'I find it difficult to believe the earthquake was severe enough to produce that kind of effect.'

'Perhaps not the earthquake itself,' Pitt said, 'but a resulting side effect. A submarine landslide set off by a minor quake might create that sort of uplift.'

A hundred and thirty miles north of the Vereshchagin and two thousand feet beneath the surface, Pitt was exactly right. The rumblings that first echoed across the lake were the shock waves from a strong earthquake, measuring 6.7 on the Richter scale. Though seismologists would later determine that the quake's epicenter was near the lake's northern shore, it created a devastating effect midway down the western flank, near Olkhon Island. A large, dry, barren landmass, Olkhon sat near the center of the lake.

Directly off the island's eastern shoreline, the lake floor dropped like an elevator down a steep slope that ran to the deepest part of the lake.

Seismic studies had revealed dozens of fault lines running beneath the lake floor, including a cut at Olkhon Island. Had an underwater geologist examined the fault line before and after the quake, he would have measured a