Firing Parties
It was a shaken group of scientists that moved off in their jeeps to the
preselected stations. Most of the adults had experienced earthquakes
before, but none had seen the earth split almost at their feet. To Rick,
the sensation had been as upsetting as any he had ever experienced.
"The one thing we learn to depend on," Zircon said, "is that the earth
under our feet is solid and dependable. When it shakes like a jelly, it
causes a kind of emotional shock, apart from any physical damage it may
do."
"It certainly did with me," Rick agreed.
"Ditto," Scotty added.
Zircon put the jeep in gear and moved away from the hotel. He drove
slowly over the narrow part of the crack in the parking lot, then picked
up speed. Rick looked around. Bradley Connel and Ruiz were following in
their own vehicle.
Zircon took a blacktop road to the west, close to the base of the
mountain. Fortunately for Rick's peace of mind, the road was fairly
smooth. He had never carried dynamite caps before, but he knew they
contained fulminate of mercury, which is one of the most unstable and
violent chemical substances, pound for pound, ever created.
The big scientist sensed his uneasiness. "Relax, Rick. Those caps won't
go off without a substantial knock against something. Enjoy the
scenery."
Rick grinned. "I'll try."
The scenery was tropical. Once away from the hotel grounds, there was
heavy growth, vines, creepers, and broad-leafed plants. He saw palmetto
and wild banana interspersed with Judas palms and other typical
vegetation. The growth clung to the side of El Viejo like a thick green
carpet. Now and then the jeep passed an open space in the vegetation and
he saw the plains stretching away to the sea on his left.
The jeep climbed gradually and Rick realized that their direction had
changed. They were now heading on the more northerly course. The
vegetation was thinner, too, and he guessed it was because they were
higher up the mountainside. At a rough estimate, the jeep had climbed
nearly a thousand feet.
"Pumice quarry ahead," Zircon announced.
Rick saw ramshackle wooden buildings, then piles of grayish rock. A
hundred yards farther on he saw an open pit. This was where the San
Luzians mined pumice for export.
"Is there much of a market for it?" Scotty asked.
"Not as much as there was years ago," Zircon replied. "Pumice, as you
probably know, is volcanic rock. But not an ordinary one. It's a kind of
foamy lava honeycombed with gas bubbles. It's used as an abrasive.
Modern industrial products have replaced it in general use, but
apparently there's still enough demand so that the San Luzians are able
to export a little. Our firing station is about a mile from here."
Rick looked at the rough terrain. "Think we can get through?"
"Easily. According to the map, we have an unpaved road part of the way."
The unpaved road turned out to be a pair of wagon tracks. But at least
there were no trees in the way. Rick held on tight as Zircon shifted
into four-wheel drive and forged ahead.
The big scientist kept an eye on his odometer, or mileage counter, while
the boys watched for a clearing. It was slightly over a mile before they
found one, and Zircon pulled off the road to let Brad Connel and Ruiz go
by.
The jeep stopped as the two came abreast and the geologist called, "Want
to trade stations?"
"We like this one," Zircon replied with a grin.
"Don't blame you. I have another three miles through this stuff. Well,
so long."
The jeep started off and was soon lost as the path curved slightly.
Zircon looked at his watch. "Plenty of time, but we might as well get
ready."
A few minutes search disclosed a spot far enough away from the clearing
for safety, with no trees to be uprooted by the blast. Zircon took two
of the dynamite sticks Rick carried and one of the caps. He placed the
cap over one stick and used a special tool, like a jar opener, to crimp
it into place.
"This is the only really delicate part of the operation," he said. "If
the crimpers slip, they could set off the cap and the dynamite. So be
careful when you do it. Keep the crimpers low on the flange of the cap."
He found a rubber band in his pocket and used it to hold the two sticks
together. A coil of wire was produced next, and the connection made to
the dynamite cap. Zircon dug a shallow hole with his heel and put the
dynamite sticks in, then backed off unwinding wire as he went.
The detonator had been left in the jeep. Rick got it and carried it to
where Zircon waited with the pair of wires.
"How does this thing work?" Scotty asked.
"It's a dynamo," Zircon replied. "When the handle is pushed down it
engages gears that spin a flywheel, which operates the dynamo long
enough to send an electrical charge through the wires."
"So don't sit on the handle," Rick joked.
"And don't kick it," Scotty added.
Zircon connected the wires to a pair of terminals on top of the
detonator, then looked at his watch. "Plenty of time. We might as well
take it easy. Anyone hungry?"
No one was. It was too soon after breakfast. Instead, Rick took the
opportunity to ask questions.
"I can understand the general principle of what we're doing, but can you
tell us exactly what happens?"
"Sure. When the dynamite charge goes off, it sends shock waves through
the earth in all directions. Whenever a shock wave strikes something of
different density, its direction and velocity change. For instance, if
there is denser rock a few hundred feet down, that will cause a change
of both velocity and direction. With me so far?"
"I think so," Scotty said. "The denser the stuff the wave strikes, the
faster it moves. Like sound waves. I mean, sound moves faster in water
than in air, and faster in a steel rail than in water. Is it the same?"
"Just about," Zircon agreed. "The shock waves radiate away from us,
through the earth, and eventually reach the recorders on the other side
of the mountain. You can see what happens, I think. Waves will arrive at
different times, depending on the path they took and the kind of
material they went through."
Rick nodded. "So if there's molten rock, or magma somewhere in the way,
the shock wave that goes through it will slow down and arrive at the
recorder later?"
"That's it. The tracings we get can be analyzed to give us a kind of
cross-sectional look at the mountain. You see, we know how fast the
waves travel through different kinds of earth structure. Also, we will
know the point of the explosion and the location of the recorder for
each shot. Which reminds me. We'd better get out the equipment and
locate ourselves precisely."
"How?" Rick asked. "What will we use for landmarks?"
"The top of the mountain, for one, and if you'll look carefully to a
point slightly south of east between those two banana palms, you'll see
the top of the control tower at the airport."
Rick shook his head. "Good thing you're with us. I completely forgot to
watch for landmarks."
"That was the first thing I had in mind in looking for a spot," Zircon
told him.
The transit gave a precise angle between the two landmarks. Zircon drew
a line on the map connecting the southern tip of the mountain and the
airport tower. Then, with that as his base line, it was easy to draw two
lines at the correct angles from each of the points. The transit's
position was where the two lines intersected.
By the time the scientist had finished, it was nearly one o'clock. The
three walked to the detonator. "Pull the handle up," Zircon directed.
Rick did so. "I'll count down from ten seconds. Push down on zero."
It was like the countdown for a rocket firing, Rick thought. Zircon
called out the time starting at one minute, then called off the last ten
seconds. As he reached zero, Rick pushed the handle home.
The dynamite went off with a roar that sent leaves and dirt flying, and
Rick felt the shock wave slam against his ears with stunning force.
"Open your mouth next time," Zircon said. "I forgot to warn you." He was
already reeling in the wire. "Let's get going. One mile farther on for
the next shot."
At the next station the same procedure was repeated, but before it was
time, there was a far-off explosion. Zircon looked at his watch. "Brad
Connel. Right on time." In another fifteen minutes there was an even
more distant sound as David Riddle's first shot went off. They ate their
lunch and listened to the echo off the mountain.
Zircon and the boys were ready when their time came. Location this time
had been made on sightings toward the mountain, and a flagpole at Cape
San Souci on the western side of the island.
The road petered out and they were forced to go cross-country to reach
the third shot station. Fortunately, Brad Connel had left a path of
crushed vegetation, so it was only necessary to follow where he had led.
After the third shot, the three collected their equipment and drove back
to the hotel.
They were the first back. All three were sticky from the heat, and
somewhat insect bitten. By unanimous consent they headed for the
showers.
Rick dressed except for his shoes, then stretched out on his bed. He
wondered what the day's work would show. The memory of the earthquake
was still fresh, and he was anxious to see if it had come from rising
magma far below, or from some other source. He had a mental image of
white-hot rock rising sluggishly, melting a path to the surface. Now and
then the magma struck water, or gas-producing minerals, and then there
was a tightly held explosion that made the earth shudder.
Well, it was probably like that, from what he had read about volcanic
action. Anyway, he could do without earthquakes. They were unnerving.
Scotty finished dressing, and Rick slipped on his shoes. It was time for
the others to be back. Connel should have arrived only a few minutes
behind them, but it would take longer for the others because they had
gone around the mountain in the other direction.
The boys walked to the staff conference room and found Hartson Brant and
Julius Weiss. The two were busy unrolling long strips of paper covered
with blue shadings.
"Find anything yet?" Rick asked his father.
"No. We're just getting ready to take a look. How did it go?"
"No trouble. Zircon must still be in the shower. Probably Connel is,
too. He must have been right behind us."
The scientists started poring over the traces.
"Here's your first shot," Hartson Brant said. He pointed to where a
series of squiggles began. Rick could see nothing of interest. All the
pen marks looked about the same to him. It would take expert analysis to
make anything out of them.
The boys left the scientists to their work and wandered out into the
parking lot. "I want to take a closer look at that crack," Rick said.
"Same here. Suppose it goes to China?"
Rick grinned at his pal. "That's a myth. If you drilled a hole straight
down through the center of the earth from here you wouldn't come out
anywhere near China. You'd be in the Southern Hemisphere."
"Don't get technical on me, boy."
The crack, however, went down only about three feet, gradually narrowing
until it was closed. Even so, it was impressive. Rick knew that the
actual break must continue down into the earth for some distance,
perhaps for hundreds of feet. The force it took to shake the earth like
that was awesome. Again he was reminded sharply of the kind of forces
against which the Spindrift group was trying to contend, and he felt for
the first time that the job was completely hopeless. What could mere men
do?
A horn honking wildly brought him to quick attention. He turned and saw
a jeep coming along the western road into the parking lot. Brad Connel!
But where was Ruiz? Then, as the jeep neared, Rick saw. The San Luzian
was lashed to an improvised stretcher lying across the back of the jeep!
The geologist drew to a stop, his face chalky.
"Get a doctor!" he shouted. "Quickly! Ruiz got caught in the last
explosion. I think he's dead!"