At work!

I have uploaded pictures of some of the equipment we will be using once we arrive in the Haitian waters. We got our clearance just yesterday to enter these waters.

We have begun to test the various instruments en route to ensure they are properly  functioning. The yellow fish-like device is called a CHIRP. The CHIRP is towed behind the boat (aft) and provides us with a continuous profile of the seafloor and its subsurface.  It is important for noting subsurface features that will help us hone in on regions of subsurface faulting.  A transducer in the CHIRP emits a frequency range between 0.5 and 12 kHz. As geologic materials in the subsurface and on the surface have different physical properties, the receiver inside the CHIRP will receive the signal at different velocities depending on the material.  

The multi-beam, a 240 kHz system, is mounted on the yellow pole alongside the starboard side of the ship.  It is useful in up to 450 m water depth and creates a map of the seafloor; aprofile extending about 250 m at either side of the boat. The side-scan sonar compliments the multi-beam as it provides a crisper resolution of areas of interest.  Mapping the seafloor will help us determine ideal sites for collecting sediment for studying the sediment record to eventually develop a paleoseismic history of Haiti.

The long silver pole is a gravity core. Inside of it is a clear plastic tubing, which will bring home with us to understand the geophysical properties of the individual cores.   The corer is attached to a wire and lowered from the A frame (picture) of the boat until it is dropped at a rapid speed to ideally recover about 8 ft of sediment. The other type of coring device you see if called a multi-corer (pic). The multi-corer  can potentially collect 4 cores at once which is useful for understanding a greater spatial area as opposed to one spot location of the gravity corer. The cores collected from the multi-corer will help us determine the age of the sediments and how fast they have been accumulating (using radionuclides). We will begin processing the multi-corer cores on the ship (cutting it into cm intervals and bagging them for later analysis). The sediment samples will be used to understand changes in lithology (meaning a variation of different sediment types provides us with information on how the environment has changed in the marine environment adjacent to Port -au Prince). Additionally, we will use surface samples to help us focus on an area that records recent disturbance (i.e. earthquake) using short-lived radioisotopes.

We are still transversing through the Bahamas. Eleuthera and San Salvador were both visible from the ship.  Now we are sailing in between Crooked and Long Islands and it is finally feeling like Caribbean weather. The sun is shining and temperatures around 80 degrees. I love the peacefulness of standing on the deck, watching the ocean, and feeling the sea undulate below my feet.  I am wearing a sea sickness patch, which I am guessing is working because we have been in pretty high seas all day and last night and I feel ok; able to read and work on the computer no problems. The maximum roll of the boat thus far has been about 18 degrees. This may not sound like much, but until you experience it you realize how significant an 18 degree roll truly is. At times if felt like the boat may tip over, although that’s highly unlikely in these seas due to the size of the keel. During meetings everyone is flying out of their chairs and inadvertently diving toward the person across from them.  Sleeping on the top bunk was interesting as well, as I had several close calls of nearly falling out of bed  (no guard rail) throughout the night. They have an exercise bike on the lowermost deck today, which I was able to complete a nearly full workout until a high angle roll caused the entire bike to topple over with me on it. Owe! Showering is also a challenge. You must hold on to something at all times.

We are all so excited to arrive to Haiti and begin collecting information, as all the data that we can gather will be mostly new . The chief scientists have devised a sampling and survey plan. They drew several survey lines on large maps, delineating how the ship will conduct the geophysical survey across the extent of what is believed to be the suture zone. The majority of surveying will be near the coastline ( as close as we can get) since a tracing of the terrestrial fault continues into the bay near to shore.  We also have no idea where the coral reefs are, since no documented reef surveys are neither available or have been conducted. Since the fault is likely near the coastline, this is also a likely location for corals. We may try to collect some coral samples to date them and determine if they can provide us with any information on recent earthquake activity. Our ETA is saturday afternoon (12?). We will first drop the tents, then deliver some supplies to a geologist working on the faults on the land, pick up 2 haitian geologists, then begin the surveying.  The tents will be transferred from our boat to a barge-like ship using a crane. To bring the supplies for the onshore geologist, a few member of our team will travel by a zodiac boat (inflatable motor boat), which will also be used to pick up the Haitian geologists.  This may also be the day when national geographic (or NOVA) will be joining us.

One Response to “At work!”

  1. Patty V Says:

    This has got to be very exciting for you. It’s hard to believe that there is little information about the area you are going to. But I guess we can’t have information about every area of the earth. Katie you are invoved with cutting edge information. I am very proud of you. OXOXOXO PV

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