magma meets enough water to create steam. Now, our closest
magma front is still far below the floor of the surrounding ocean. You
follow me? Good. When the magma rises to the level of the ocean floor,
what do you think will happen?"

Rick could see the picture in his mind. He said slowly, "It will
probably meet water. Plenty of it, from seepage of the ocean downward
through cracks in the ocean floor. Maybe there are cracks like the one
in the parking lot, caused by earthquakes."

"Precisely. And when the magma meets the water, then what?"

"The water turns to steam instantly." Scotty answered grimly. "The steam
expands instantly--and boom!"

"Boom," Balgos agreed solemnly. "But how big a boom we do not know. It
may blow the top off El Viejo. It may blow a gap along one of the
cracks. We don't know."

Rick digested this information in silence. The picture was certainly not
a cheerful one. "How far down are the magma fronts?" he asked.

"As closely as we can tell, the bottom one is right above the
discontinuity, which is about six miles below us at this point. The
upper one is about a mile below the top of El Viejo. This puts it about
a quarter of a mile below the floor of the ocean."

"Too close," Scotty muttered. "What now?"

"We keep shooting, to try and keep track of the upper front. Also, we
will place instruments called tiltometers on the mountain slope. These
are devices that really measure tilt. You see, if the lens of magma is
increasing, El Viejo will swell up slightly. The tiltometers will show
it, and we will then have further proof of what is coming."

"But what can we do about it?" Rick demanded.

Balgos shrugged. "_Quien sabe?_ The Spanish phrase is a good one,
because it does not only ask 'who knows,' it also carries the meaning of
a kind of resignation. There does not seem to be anything we can do."

Rick stared across the dining room, eyes unseeing. It was hard to
imagine that molten rock was gathering below them in sufficient quantity
to make a mountain move; but once you succeeded in imagining it, the
picture was terrifying.

Motion attracted his glance and his eyes focused in time to see Brad
Connel rise from the table and excuse himself. He watched the geologist
walk out of the room and turned to Scotty. His pal nodded. He had seen
Connel leave, too.

Rick quickly counted noses. All others were present. Connel was the
first to leave. He wondered where the geologist was going, and his