Meanwhile, at sea…

While our shore-based counterparts brave the bears and the weather, our sea-faring crew of old salts continues to deploy the offshore stations. We’ve come up back towards Kodiak Island and deployed our last shallow water seismometer with a trawl resistant shield yesterday (TRM). We would be nowhere without our team of six engineers from Lamont-Doherty Earth Observatory that build the data loggers, mount the sensors and batteries, test to make sure everything is working and deploy the package with the help of the deck crew. Here are a few of them posing with our last TRM:

last_trm

Fearless, awesome OBS engineers with our final TRM

The deck is looking very empty these days—ready for some soccer or yoga or sunbathing–good thing it’s heated! We have just three more instruments to deploy. That’s a far cry from the 48 we left Seward with ~2.5 weeks ago!

close_to_empty_deck

Our almost-empty deck

Before we deploy our final instruments and steam back to Sikuliaq’s home port, we are taking time to do some seafloor mapping using the ship’s acoustic multibeam and sub-bottom profiler systems. The first shoots out a swath of high-frequency energy that bounces off the seafloor. We record those pings and use that to map seafloor features and determine depth.

bathy_raw

Multi-beam data seen in real time

You can see the remarkable difference in detail comparing the global dataset in the background with higher resolution ship-track data, below. A ~5 mile wide channel (basically a river on the seafloor) curves down the slope towards the Aleutian trench. The raw data is processed to remove extraneous points and gridded to make surfaces like these.

bathy

Ship-track multibeam data from the R/V Langseth taken in 2011 near the Shumagin Islands shows a huge slope channel

The sub-bottom profiler uses a frequency band that can penetrate the seafloor and image shallow subsurface sediment layers. Today, we’re hoping to catch an active fault strand northeast of Kodiak Island.

AACSEex1

Sub-bottom profiler data from the continental shelf near Kodiak Island – gorgeous!

As I write this, the sun is getting ready to come up. I won’t miss waking for my 3 am shift everyday, but I will miss the Gulf of Alaska sunrise and the view from Sikuliaq.

baow_sunrise

A pretty good sunrise off the bow

Lindsay Worthington, University of New Mexico

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