Keck Expedition 2004
TIBURON WAX CORES: These are
specially designed cylinders that are filled with a special kind
of wax (researchers used "Surfwax" up until a few years
ago!) which stays sticky in the cold deep ocean water. The
manipulator arm on the ROV Tiburon grab hold of the wax
cores by means of a cylindrical rubber handle and literally
"whack" the wax covered end onto volcanic rock. (See
picture above left - the handles of the corers can be seen
clearly in the foreground)
The glassy surface of the rock (which forms when lava cools
rapidly) sticks to the wax. Even just a small amount of wax
is sufficient to run tests on to determine trace and major
elements that are present in the rocks. This analysis will
give something similar to a "genetic makeup" of the
rock, letting scientists know of its origin.
Deployment of the broadband seismometer systems on this leg will
require the use of elevators as a way to shuttle the equipment
safely to the seafloor and back again. The elevators have
flotation on the top, a basket for holding the equipment in the
middle and an anchor that can be released to let everything float
back to the surface. We have two elevator types, both
designed and tested by Mike Conway. One elevator will be used to take new batteries and data logger down to the existing broadband site. The second type of elevator is more complex. It will take everything down to the seafloor that the ROV Tiburon will use to install the two new broadband sites.
Homers: Actually called Sonardyne
Homerpro's, these are acoustic beacons that we use to mark
equipment or sites that we will need to return to at some later
time. The beacons that we put with our equipment here on the Juan
de Fuca plate have batteries that are good for five years. Each
beacon has its own frequency. The beacons get interrogated by the
ROV which then can triangulate to the spot and find the gear.
These beacons have proven to be very useful as we do not need to
maintain a complete navigation system for equipment placed several
Water Lifter: the water lifter and the
suction pump are the tools that are used to sink the caisson (a
PVC pipe) to make a hole for the broadband sensor package. The
water lifter is a multistage water jet that breaks up cohesive
Suction pump: Once the sediment is broken
up by the water lifter, then a suction pump removes the sediment
from the hole and spits it out behind the vehicle. Without this
the ROV would soon be blinded by clouds of mud in front of the
Once the broadband sensor package is placed into the caisson, we
need to cover the entire thing with small diameter glass beads.
The process of "beading in" the package reduces the
noise on the instrument caused by tidally-driven bottom currents.
Our instruments are so sensitive that they get disturbed by bottom
currents even at the 2000 m water depths where we will place them.
By lowering the oceanographic and pressure noise we will enhance
the smaller seismic events in the data record.
The beads are carried down in a plastic bead hopper with a hose to fill the caisson. The filled bead hopper is actually fairly heavy, so it sits on the elevator with its own flotation. The ROV will carry the bead hopper over to the caisson to fill the hole, then place the empty container back onto the elevator for recovery.
Seismonument: the seismonument is the portable borehole
Seismometers: Short period or corehole seismometers are placed into predrilled holes or into the seismonument
Broadband: Broadband seismometers are
placed into caissons which are holes in sediment.
Benthic Toolsled: You can see the manipulator arm at the upper left side of the photo and the sample drawer with partitions in the lower left. The drawer is shown open on deck, full of rocks. Normally it is closed when the vehicle is operating and only open when a sample needs to be stowed. The partitions help us keep the rocks in order. The rocks look so much alike, all covered in manganese, but the conditions of each eruption are different, and therefore the chemistry of rocks from each vent is different, so it is important to know where each rock came from.