Treasure of Khan

movement of less than three millimeters. Yet those three millimeters was sufficient enough to create what the scientists call a 'fault rupture with vertical displacement,' or an underwater landslide.

The unseen effects of the quake sheared off a mountain-sized hunk of alluvial sediments nearly twenty meters thick. The runaway chunk of loose sediments slid down a subterranean ravine like an avalanche, accumulating mass and building momentum as it went. The mountain of rock, silt, and mud fell a half mile, obliterating underwater hills and outcroppings in its path before colliding with the lake bottom at a depth of fifteen hundred meters.

In seconds, a million cubic meters of sediment was dumped on the lake floor in a dirty cloud of silt. The muffled rumble of the massive landslide quickly fell away, but the violent energy produced by the slide was just unleashed. The moving sediment displaced a massive wall of water, driving it first to the bottom ahead of the landslide and then squeezing it up toward the surface. The effect was like a cupped hand pushing under the surface of a bathtub. The force from millions of gallons of displaced water had to be redirected somewhere.

The submarine landslide had fallen in a southerly direction off Olkhon Island and that was the direction that the mounting swell of water began to move. To the north of the slide, the lake would remain relatively undisturbed, but to the south a rolling wave of destructive force was released. At sea, the moving force of water would be labeled a tsunami, but in the confines of a freshwater lake it was called a seiche wave.

An upsurge of water punched the surface in a ten-foot-high rolling wave that drove south along the lake's lower corridor. As the wave pushed into shallower depths, the upswell squeezed higher, increasing the size and speed of the surface wave. To those in its path, it would be a liquid wall of death.

On the bridge of the Vereshchagin, Pitt and Gunn tracked the development of the killer wave with growing alarm. An enlarged three-dimensional map of the lake south of Olkhon Island showed a swirl of orange dots jumping in rapid succession across an expanding line.

'Dial up the surface pods only, Rudi. Let's find out exactly what's going on up top,' Pitt requested.

Gunn typed a short command into the computer and a two-dimensional image suddenly appeared on the monitor, showing an array of surface pods bobbing over a five-mile stretch of the lake. All eyes on the bridge focused on the screen as one orange pod after another visibly jumped in a slow line of progression from north to south.

'It's a rolling wave, all right. The sensors are getting kicked up almost five meters as it passes,' Gunn reported. He double-checked his measurements, then nodded silently to Pitt and Sarghov with a grim look on his face.

'Of course, a landslide would produce such a wave,' Sarghov said, comprehending the electronic images. The Russian pointed to a map of the lake pinned to the bulkhead. 'The wave will pass through the shallow delta of the Selenga River as it moves south. Perhaps that will dilute its force.'

Pitt shook his head. 'As the wave moves into shallower water, it will likely have the opposite effect and increase its surface force,' he said. 'How fast is she moving, Rudi?'

Gunn toggled the computer mouse and drew a line between two pods, measuring their distance apart.

'Based on the spikes in the sensors, the wave looks to be traveling about one hundred twenty-five miles per hour.'

'Which will put it upon us in about fifty minutes,' Pitt calculated. His mind was already racing in overdrive. The Vereshchagin was a stout and stable vessel, he knew, and stood a good chance of steaming through the wave with minimal damage. The greater harm would be to the lake's prevailing marine traffic, small fishing boats and transport vessels not designed to withstand the onslaught of a ten-foot wave. Then there were the shoreline inhabitants, who would be subject to an unexpected flooding of the lowlying areas around the lake.

'Dr. Sarghov, I suggest you have the captain issue an immediate emergency warning to all vessels on the lake. By the time anyone catches sight of the wave, it will be too late to get out of its way. We'll need to contact the authorities on shore to evacuate all residents at risk to flooding. There's no time to lose.'

Sarghov beat a path to the ship's radio and issued the warning himself. The radio hummed with chatter as a myriad of respondents called back to confirm the emergency. Though Pitt didn't speak Russian, he could tell by the tone of skepticism in the replying voices that at least some thought Sarghov was either drunk or crazy. Pitt could only smile when the normally jovial scientist turned red and spat a series of obvious obscenities into the microphone.

'Idiot fishermen! They're calling me a fool!' he cursed.

The warnings took heed when a fishing boat in the protected cove of Aya Bay barely survived capsizing as the fringe of the wave passed by and its captain hysterically reported the event. Pitt scanned the horizon with a pair of binoculars and could make out a half dozen black fishing boats motoring toward the safety of Listvyanka, in addition to a small freighter and a hydrofoil ferry.

'I guess you got their attention, Alex,' Pitt said.

'Yes,' Sarghov replied with some relief. 'The Listvyanka Police Department has issued alerts to all stations around the lake and is going door-to-door to evacuate risky areas. We've done all we can do.'

'Perhaps you would be kind enough to have the captain apply full speed and move us toward Listvyanka and the western shore of the lake as quickly as possible,' Pitt said, smiling that Sarghov had neglected their own plight.

As the Vereshchagin turned toward Listvyanka and increased speed, Gunn eyed the map of Lake Baikal, rubbing his finger across the lower toe of the lake, which angled to the west.

'If the wave holds its southerly track, we should be positioned away from its primary force,' he remarked.

'That's what I'm banking on,' Pitt replied.

'We are eighteen miles from Listvyanka,' Sarghov said, peering out the bridge window toward the western shoreline. 'We will be cutting it close, as you say.'

At Listvyanka, an old air-raid alarm was sounded as the panic-stricken residents pulled ashore their small boats, while larger vessels were secured tightly to the docks. Schoolchildren were sent home with warnings for their parents, while dockside shops were swiftly closed. En masse, the residents around the lake moved to high ground and waited for the mountain of water to wash through.

'It resembles the Irish Derby out here,' Sarghov said, peering out the bridge window with a humorless grin. Nearly a dozen vessels dotted the horizon ahead of them, driving toward Listvyanka at top speed as if pulled by a magnet. The Vereshchagin's captain, a quiet and steady man named Ian Kharitonov, gripped the ship's wheel tightly, silently urging his vessel to sail faster. Like the others on the bridge, he periodically took sneak peeks toward the northern section of the lake, looking for signs of the impending wave.

Pitt studied the ship's radar, noting a stationary object lying ten miles to the southeast of their position.

'Apparently, someone still didn't get the word,' he said to Sarghov, motioning toward the radar target.

'The fool probably has his radio turned off,' Sarghov muttered as he trained a pair of binoculars out the portside window. In the distance, he could just make out a faint black speck moving slowly across the lake to the east.

'Heading right for the middle of the tempest,' Sarghov said, grabbing the radio microphone again.

Hailing the lone vessel several times brought only silence.

'Their ignorance will mean their death,' he said slowly, shaking his head as he hung up the microphone.

His anguish was broken by the approach of a loud thumping noise that rattled the windows of the bridge.

Skimming low above the water, a small helicopter swooped directly toward the Vereshchagin's bridge before suddenly pulling up and hovering off the starboard wing. It was a Kamov Ka-26, an old Soviet civilian helicopter that saw its heyday in the 1960s as a utilitarian light transport craft. The chopper sported a faded coat of silver paint garnished with a seal from the Limnological Institute plastered prominently on the fuselage. The thirty-five-year-old helicopter dipped closer to the boat as its cigar- chomping pilot tossed a genial wave toward the men on the bridge.

'Have released all of the survey pods. Permission to park this whirlybird and get her tied down before surf's up,' crackled the deep voice of Al Giordino over the radio.

Sarghov stood and stared out the bridge, looking aghast at the movements of the adjacent helicopter.

'That is a valuable asset of the institute,' he said hoarsely to Pitt.