Submerging the rest of Vastitas would take about twenty more M-years, as the amount of water necessary to fill Vastitas Borealis was much greater than that needed to fill Hellas. But the pumping operation up there was bigger as well, so things were proceeding apace, and all the acts of Red sabotage combined could do no more than put a dent in this progress. In fact progress was accelerating despite increasing acts of sabotage and ecotage, because some of the new mining methods being put into use were quite radical, and very effective. The news programs showed video of the latest method, which set off big underground thermonuclear explosions, very deep under Vastitas. This melted the permafrost over large areas, providing the pumps with more water. On the surface these explosions were manifested as sudden icequakes, which reduced the surface ice overhead to a bubbling slurry, the liquid water soon freezing on the surface, but tending to stay liquid underneath. Similar explosions under the northern polar cap were causing floods nearly as vast as the great outbursts of ‘61. And all that water was pouring downhill into Vastitas.

Down at the office in Odessa, they followed all of this with professional interest. A recent assessment of the amount of underground water in the north had encouraged the Vastitas engineers to shoot for a final sea level very near the datum itself, the 0-kilometer contour that had been set back in the days of sky areology. Diana and other hydrologists in Deep Waters thought that subsidence of the land in Vastitas, as a result of the mining of aquifers and permafrost, would cause them to end up with a sea level somewhat lower than the datum. But up there they seemed confident they had factored that in, and would reach the mark.

Fooling around with various sea levels on an office AI map made it clear what shape the coming ocean was likely to have. In many places the Great Escarpment would form its southern shoreline. Sometimes that would mean a gentle slope; in the fretted terrain, archipelagos; in certain regions, dramatic seaside cliffs. Broached craters would provide good harbors. The Elysium massif would become an island continent, and the remains of the northern polar cap would as well— the land under the cap was the only part of the north well above the 0-kilometer contour.