Meg Stewart: Aleutian Islands, Bald Eagles, Wildflowers, and Bunkers, July 8, 2019


NOAA Teacher at Sea

Meg Stewart

Aboard NOAA Ship Fairweather

July 8 – 19, 2019


Mission: Cape Newenham Hydrographic Survey

Geographic Area of Cruise: Aleutian Islands, Bering Sea

Date: July 8, 2019

Weather Data from the Bridge
Latitude: 54° 59.104 N
Longitude: 166° 28.938 W
Wind: 21 knots SE
Barometer: 1006.6 mb
Visibility: 10 nautical miles
Temperature: 53° F or 11.5° C
Weather: Partly cloudy, no precipitation

Science and Technology Log

Today, we left the port at Dutch Harbor, Unalaska, Alaska and headed toward Cape Newenham. The mission for the Cape Newenham project is to gather detailed ocean depth data in order to knit together a comprehensive and highly detailed surface chart of the seafloor near Cape Newenham. I will talk about that process in my next post.

view of Dutch Harbor
A view of Dutch Harbor, Unalaska. The surrounding hills are volcanic, with just a thin layer of soil, and not a tree to be seen.

Dutch Harbor is a small town with a relatively deep port. The Ship Fairweather has a draft of 15.5 feet. “Draft” is the vertical length between the surface of the water and the bottom of the ship, which is called the hull. A ship’s draft determines the minimum depth of water a vessel can safely navigate and dock at a port. However, though the Fairweather has a 15.5 foot draft, the crew prefers a 20 foot depth of water at a port.

Map of Bering Sea
This overview map shows where Dutch Harbor is in relation to Alaska, the Pacific Ocean, the Aleutian Islands, the Aleutian Trench and Russia. The A-B line is shown for the cross sectional line in the next figure. Cape Newenham is out next destination.

Dutch Harbor is part of Unalaska Island, which is one of the string of Aleutian Islands. The Aleutian Islands are part of the notorious Ring of Fire that marks the edge of the Pacific tectonic plate. As the Pacific Plate moves and grinds past some plates (like along the North American Plate at the San Andreas Fault) or pulls away from other plates (like the Antarctic and Nazca plates, creating the East Pacific Ridge) or plunges beneath other plates (like the Philippine and Indian-Australian plates, where we get deep ocean depressions called the Mariana Trench and Tonga Trench, respectively), we see active volcanism (which is the “fire”) but also lots of earthquakes. The Aleutian Islands are volcanic in origin – the island chain is a volcanic arc – and are a result of oceanic crust of the Pacific Plate being subducted under the oceanic crust of the North American plate. The deep depression at this tectonic boundary – also called a subduction zone – is called the Aleutian Trench.

Aleutian Trench
Referring to the A-B line shown in the overview map above, this cross section shows the mechanics of the subduction zone at the Aleutian Trench at Unalaska Island.
Aleutian Trench tectonic map
This is a tectonic map of the Aleutian Trench area (the symbol shown as a dark black curved line indicates a subduction zone). The map shows the relative motion of the Pacific and North American plates. It is clipped from the New York State Earth Science Reference Table

Looking at a schematic drawing of the side-view, or cross section, of the Aleutian subduction zone, we can visualize what this looks like beneath the surface. The older and more dense oceanic crust of the Pacific Plate is plunging under the younger oceanic crust of the North American Plate – the more dense material sinks down or subducts – and the less dense material stays floating on top, and this process is all due to gravity. With time, as the oceanic material is drawn deeper into the subduction zone, it becomes hotter, starts to melt and then comes back up to the surface as volcanic material and a string of volcanoes forming parallel – and in this case, forming an arc – to the boundary between the Pacific Plate and the North American Plate.

Personal Log

Arriving at NOAA Ship Fairweather
Arriving at NOAA Ship Fairweather

I arrived at Dutch Harbor on July 6, after 14 hours and three legs of air travel. Fortunately, I made all my connections and my luggage arrived at the tiny Dutch Harbor airport. I was picked up by welcome smile for a nice person from the Ship Fairweather, got to the port and settled in to my stateroom. The “stateroom” is my sleeping quarters or room. I have it all to myself, it is very comfortable with a sink, a small bed, drawers and a closet to fit all my stuff, and there’s a TV that I haven’t yet figured out how to work.

My stateroom
My stateroom or sleeping quarters. Caution: panoramic photos make everything look larger than they really are.

Did You Know?

On my second day in Dutch Harbor, I went out with some new friends from the ship on a lovely hike on nearby Bunker Hill. I saw so many beautiful wildflowers along the trek and an enormous number of bald eagles. I had no idea that bald eagles would be so plentiful here, but they were everywhere. It was amazing! But the other interesting thing about this hike were the bunkers.  In June 1942, Dutch Harbor was bombed by the Japanese Navy (six months after Pearl Harbor) during World War II. At the time of the raid, Alaska was a U.S. territory, and following the bombing, the bunkers of the now-known-as Bunker Hill were built to help defend not only Alaska but the west coast of mainland U.S. And here I thought Dutch Harbor was only known for Deadliest Catch!

Quote of the Day

“Even if you never have the chance to see or touch the ocean, the ocean touches you with every breath you take, every drop of water you drink, every bite you consume. Everyone, everywhere is inextricably connected to and utterly dependent upon the existence of the sea.” Sylvia Earle

9 responses to “Meg Stewart: Aleutian Islands, Bald Eagles, Wildflowers, and Bunkers, July 8, 2019

  1. Okay I can’t decide what I am most blown away with: your location, the flowers, the bald eagles or the thin soil and volcanic rock/origin. Thanks for sharing, so fantastic and inspriing!

    • Thanks, Miriam! I can’t decide either! Plus, I’ve been learning a ton about what NOAA does and will squeeze that info in sometime soon. (Oh, and I’ve see a couple of whales too)

  2. Oh my oh my— this is an incredible journey and I am so thrilled to be joining you on it through this blog!
    What amazing adventures you are embarking on— I can’t wait to learn all about this!
    PS: I love your cozy quarters!

    • Thanks so much, Paula! I’m so glad you’re following along! Also, the TV situation in my cozy quarter got remedied 😉

  3. Your adventures sound amazing! I enjoyed your blog and learning more about your experiences! Looking forward to the next. Enjoy Meg!! 💕

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