s we don't
suspect. We'll know when we start shooting."

Hartson Brant looked at Dr. Williams. "Anything to add, Jeff?"

"Not much. I've gone over the seismic data Esteben got from the
seismologists in the area, and it's clear that the epicenter of most
recent earthquakes in the area is right under us. Something is happening
down in the earth under the mountain, but I can't say what it is. It may
be volcanism or it may be a fault shifting."

Rick knew that a fault was like a great crack in the earth's structure,
but he had thought the scientists had agreed that the earthquakes were
caused by volcanic action. He asked, "Sir, doesn't the change in the
springs mean something?"

"Perhaps, Rick," Dr. Williams answered. "We don't really know. Dr.
Balgos thinks they mean a great deal, and I have respect for his
opinions. But I'm only a seismologist. I have to depend on traces from
earthquakes, and the traces tell us nothing but the single fact that
something is going on far below."

Hartson Brant nodded. "The answer will depend on more data, so today
we'll start to collect it. Rick and Scotty brought apparatus, and the
governor has supplied us with dynamite and two experienced helpers, Ruiz
and Honorario."

"How do we split up?" Julius Weiss asked.

"Into firing and recording teams. Since we have only two recorders, we
can have only two teams for data collection. But we can have three
firing parties. Dave Riddle will work with Honorario, Brad Connel with
Ruiz, and Hobart Zircon with Rick and Scotty. Julius, you and I will
form one recording party, and Esteben and Jeff will form the other. Each
team will have a jeep. Now, if you'll all gather around this model the
boys made, we'll pick approximate locations for stations."

The boys had brought the model with them. Now the group gathered around
and discussed the best locations for both firing and recording parties.

Dave Riddle was assigned a station on the slope of El Viejo near the
town of Redondo on the north end of the island. Brad Connel was given a
location on the northwestern slope, and Zircon and the boys were shown a
position on the west near the place where pumice, a foamy volcanic rock,
was mined. Hartson Brant and Julius Weiss were to place one recording
station on the eastern slope of the mountain, while Dr. Williams and
Dr. Balgos were assigned a station on the northern coast.

Hartson Brant handed a wrist chronometer to each team leader. Each team
was