NOAA Teacher at Sea
Victoria Cavanaugh
Aboard NOAA Ship Fairweather
April 16-27, 2018
Mission: Southeast Alaska Hydrographic Survey
Geographic Area of Cruise: Southeast Alaska
Date: April 26, 2018
Weather Data from the Bridge
Latitude: 54° 40.914′ N
Longitude: 134° 05.229′ W
Sea Wave Height: 8-9feet
Wind Speed: 15 knots
Wind Direction: NNW
Visibility: 10 km
Air Temperature: 9.5oC
Sky: Partly Sunny in the AM, Cloudy in the PM
Science and Technology Log
Over the past two days, the crew of NOAA Ship Fairweather has been hard at work on the first major project of the season, charting the ocean floor along the Queen Charlotte-Fairweather Fault System. The project itself will take seven days, though with two days at sea before heading to port in Ketchikan, the survey techs have been focusing on the first sheet, D00245, roughly 900 kilometers offshore in an area known as West of Prince of Wales Island.
Fairweather is completing the survey in collaboration with the United States Geological Survey (USGS) which has spent the last three years researching and mapping the seafloor along the fault. Geologists are particularly interested in this fault as little is known about the region and the seafloor here is largely unexplored. Geologists believe that by studying the fault line and the geology of the ocean floor, they may be able to unlock secrets about the history of our oceans as well as develop new understanding of seismic activity that can keep communities safer when future earthquakes strike.
One of the reasons the USGS turned to NOAA to complete its charting efforts is because of the tremendous ocean depths. The survey techs are using Fairweather‘s multibeam echosounders for the project which will take a total of seven days to complete. Sonar pings from the ship’s transducer hit the ocean floor and bounce back to the ship, creating 2D and 3D charts of the ocean floor. Additionally, survey techs can learn more information about the type of surface on the ocean floor (sandy, rocky, etc.) based on the strength of the return of the sonar pings. Despite the seafloor in the area being some 15,000 years old, it has never been explored! Thus, for the survey techs and geologists working on this project, there is a sense of pure excitement in being able to explore and discover a new frontier and help others sea what humans have never seen before.
One of the geologists remarked that he was surprised to see that despite how old the ocean floor in the area is, little appears to have changed, geologically speaking in thousands of years. Another surprise for geologists is how the fault appears to be one large, long crack. Many other fault areas appear to be made up of lots of small, jagged, and complicated “cracks.” Another question to explore!
Notice the colors which help survey techs see the changing depths quickly. The green, mostly vertical lines, show the ship’s course. To collect data, Fairweather runs about 6 hours in one direction, before turning around to run 6 hours in the opposite direction. This allows survey techs to gather more data about ocean depths with each turn. In total, survey techs collected nearly 48 hours of data. This meant survey techs working all night long to monitor and process all of the new information collected.
Just like on the launches during patch tests, survey techs deploy CTD’s to measure the water’s conductivity (salinity), temperature, and pressure. This information is key in order to understand the speed of sound in a given area of water and ensure that the sonar readings are accurate.
Personal Log
In striking contrast to the beautiful coastlines that framed the Inside Passage, the last two days have provided endless blue skies mixing with infinite blue seas. No land in sight!
The open ocean is challenging (huge waves make the entire ship sway constantly and gives new meaning to earning one’s “sea legs”), but far more inspiring. I’m grateful for the glimpse into life at sea that NOAA has provided me. There is deep sense of trust among the crew, in their collective hard work that keeps us all safe in the middle of the ocean. There is also a wonderful sense of adventure, at being part of discovering something new. Just as explorers have sought after new frontiers for hundreds of years, Fairweather today is charting areas still unknown to humankind. There is something truly invigorating about watching the sonar reflect the ocean floor in a rainbow of colors, in watching as peaks and valleys slowly are painted across the monitors in the plot room and bit by bit, another sliver of science is added to the charts. There is something particularly refreshing and exciting about seeing whales spray and play in the waves while standing on the ship’s bridge. I’m truly grateful to all onboard Fairweather and NOAA’s Teacher at Sea Program for this remarkable opportunity, and I look forward to sharing what I’ve learned with students back at Devotion.
Did You Know?
Prince of Wales Island is one of the southernmost parts of Alaska. Home to some 4,000 inhabitants, Prince of Wales Island is the 4th largest island in the US and the 97th largest island in the world. Originally home to the indigenous Kaigani Haida people, Spanish, British, and French explorers all passed by the island in the 1700 and 1800’s. In the late 1800’s, miners came to the island looking for gold, copper, and other metals. Today, most of the land is protected as the Tongass National Forest covers a great portion of the island.
Challenge Question #5: Devotion 7th Graders – Can you find the depths of the Charles River, the Boston Harbor, and 900 kilometers offshore the Massachusetts coast? What sort of aquatic life exists in each area? What does the river/seafloor look like in these areas? Create a comic strip or cartoon showing your findings.
This is your favorite 7-4 student, Isabelle Pena. Charles river is 25.9 feet deep. The end of the Boston Harbor is 35 feet and the channel extending from Boston Harbor to the Northern Avenue Bridge in South Boston, is 23 deep.
“This is your favorite 7-4 student, Isabelle Pena.” WOW