Linda Kurtz: Bathymetry – Who Knew? August 20, 2019

NOAA Teacher at Sea

Linda Kurtz

Aboard NOAA Ship Fairweather

August 12-23, 2019


Mission: Cascadia Mapping Project

Geographic Area of Cruise: Pacific Northwest (Off the coast of California)

Date: 8/20/2019

Weather Data from the Bridge:

Latitude: 41°04 N
Longitude:  124° 37 W
Sky Conditions:  Scattered Clouds
Present Weather:  Foggy
Visibility: 3 Nautical Miles
Windspeed: 2 knots
Sea Wave Height:  0
Swell Height: 2 feet
Temperature:  60° Fahrenheit


Bathymetry

What is Bathymetry and why is it important?  Bathymetry is the foundation of the science of hydrography, which measures the physical features of a water body. 

We covered Hydrography in the last blog post so we know it includes not only bathymetry, but also the shape and features of the shoreline and more.

Bathymetry is defined as “the study of the “beds” or “floors” of water bodies, including the ocean, rivers, streams, and lakes.” 

The term “bathymetry” originally referred to the ocean’s depth relative to sea level, although it has come to mean “submarine topography,” or the depths and shapes of underwater terrain.  In the same way that topographic maps represent the three-dimensional features of land, bathymetric maps illustrate the land that lies underwater.  Variations in sea-floor relief may be depicted by color and contour lines called depth contours or isobaths.  (Click here for source credit and more information from NOAA)

A bathymetric map looks like this (thanks Sam!):

bathymetric map
Latest bathymetric maps! Can you see the newly discovered undersea canyon?
(Southern coverage)
bathymetric map - north
Latest bathymetric maps! Can you see the newly discovered mud volcano?
(Northern Coverage)

Above are the first views of this part of the seafloor with a bathymetric map!  (Color coded for depth – see the chart on the left)


Science and Technology Log:

Among the NOAA officers Navigating the ship, Hydrographic Technicians, and wage mariners aboard Fairweather, and the Teacher at Sea, there are also two guest USGS scientists:  James Conrad, a research Geologist and Perter Dartnell, a physical scientist.  USGS stands for United States Geographical Survey.  The USGS was created by an act of Congress in 1879 and is the sole science agency for the Department of the Interior. 

As a Teacher at Sea, I had time to talk with these USGS scientists and learn more about Bathymetry and why it is important not only to scientists, but also how this information can be used to keep us safe. 

Discussion with James Conrad research Geologist who is utilizing the science of Bathymetry among others to map the Cascadia Region of the Pacific seafloor. The USGS scientists’ focus is mapping the Cascadia Subduction Zone where the Juan de Fuca tectonic plate is “diving” below the North American tectonic plate. Areas of particular interest to these scientists are finding new faults, faults that are known but we have little information about, mud volcanoes and subsequent “seeps,” and the overall goal is to understand the behavior of the mega thrusts in the Cascadia Region. 

map of tectonic plates
Image Credit: USGS scientists Peter Dartnell and James Conrad

About the visiting scientists:

James Conrad has a bachelor’s degree from U.C. Berkley and a master’s degree from San Jose State and has been at the USGS for 38 years.

A conversation with Research Geologist James Conrad:

What do you want students to know about Geology?

Geology is a field where there is still so much to discover, especially if you are doing hazards research work-like earthquakes, tsunamis, landslides, coastal change, and climate change issues

Were you always interested in geology?

Not as a child, but I became a geology major because I had taken an introductory course – and was guided to geology by the university.

I met you on a ship-where do most of your work?

Office is in Santa Cruz, but we go out in the field 1-4 times a year for a week up to 3 weeks. 

Geology is a very young science, the fact that continents move wasn’t proven until 1963.  There is very little known about the earth, and there is so much more to discover.

Peter Dartnell:

Peter Dartnell has Bachelor of Science in Oceanography from Humboldt State University and a Masters of Geography from San Francisco State and has been with the USGS for 28 years.

A conversation with Physical Scientist Peter Dartnell:

What does a physical scientist study?

Physical Science is a combination of the studies earth and computer sciences using computers & technology to study earth.

Physical Science allows you to do everything along the scientific “study train” from data collection, interpretation, to publications.

What are your publications used for? 

Scientific publications from the USGS (which is the science agency of the government) are used widely to inform about potential geohazards and changes in the earth.  We don’t make policy, but the information we provide may be used drive policies, especially safety.

Anything you want an aspiring physical scientist to know? 

Even though you are studying earth sciences in school, you’ll truly enjoy once you get out and start applying what you’ve learned in the field with hands on science. 

We’ve met on a ship, where is it you do most of your work?

I spend 75% of my time in the office and 25% in meetings or traveling to study

What is your favorite part of being a Physical Scientist?

Seeing part of the ocean that nobody has ever seen for the first time. We are the first ones to see these recently mapped parts of the sea floor. 

What types of technology you use in physical science?

We use specialized software to acquire data and analyze the data we collect.

We also use Multibeam sonar software – bathymetry and acoustic backscatter

GIS geographic information systems

Overlay/Compare and Contrast data

What do you think are some misconceptions about physical science?

Because we are working off shore and water covers 71% of the earth, marine geology is in its infancy — we really need to have a complete map of the sea floor which is vitally important to understand the geology of the earth. When we don’t have all of these details, we are essentially operating blind.  That’s why the work that NOAA is doing is so important and the research partnerships with USGS are so valuable.

Much of the geography of the seafloor is driven by the oil industry which is required to release their acquired data every 25 years.  A lot of the deep penetration data is all from oil surveys.  Sea floor mapping is limited for pure research purposes due to limited resources.

Interested in learning more from the USGS? 

Check out these resources for students and teachers:

Escape the POD challenge for grades 6-12

K-2 Resources

3-5 Resources

More about bathymetry and the NOAA and USGS mission:

I was lucky enough to attend a “Science Talk” by these USGS scientists which was titled the Subduction Zone Coastal & Marine Geohazards Project. The USGS scientists are guests aboard Fairweather like me. 

The focus of the USGS research is along the 700-mile Cascadia Subduction Zone:                                                                                                                                  

study area
Map of Study Area. Image Credit: USGS scientists Peter Dartnell and James Conrad

This area is where the Juan de Fuca plate dives below the North American Plate at an approximate rate of 1.6 inches per year.

Subduction Zone
Subduction Zone Image Credit: USGS scientists Peter Dartnell and James Conrad

Why is this subduction zone so important and why is NOAA Ship Fairweather out surveying the ocean floor in this area?  That’s because the world’s largest and most destructive earthquakes occur along subduction zones.  If we know the potential hazards, we can prepare people and potentially save lives.

To properly prepare, we need the following details:

slide preparing for earthquakes
What We Need to Prepare for Future Earthquakes
Image Credit: USGS scientists Peter Dartnell and James Conrad

This is why the bathymetric maps of the sea floor are important, they can help predict the area and amount of shaking that may occur during an earthquake and predict the tsunami danger zones.  Then we can make decisions for building codes, infrastructure (like strength of bridges), and escape routes for Tsunamis.  I took the pictures below when I arrived in Newport, little did I know how the research the Fairweather is conducting and the science of hydrography and bathymetric maps play a part in warnings like these! (See below)

Through the hydrographic surveying being conducted aboard Fairweather, the NOAA crew and USGS scientists are creating bathymetric maps which have reveled exciting new finds, such as: new seafloor faults, mapping known faults in greater detail, discovering mud volcanoes and submarine landslides, and using the water column data to discover the “seeps” which are most likely releasing methane gas.  See below.

(Image Credits: USGS scientists Peter Dartnell and James Conrad)

When I first heard the term BATHYMETRY I had no idea how these detailed maps of the seafloor could hold so much critical information!  It’s fascinating to watch this science happen right here and see the discoveries in real time. 


Personal Log

This post begins the last week aboard Fairweather.  I’m surprised about how quickly the ship has begun to feel “normal” to me.  I know my way around backwards (aft) and forwards (bow) and enjoyed getting to know everyone better.  Sean the IT specialist makes an amazing pot of French press coffee around 10:00 am and is kind enough to share with all.  Bekah, Sam, Joe, and Michelle in Hydrography patiently answer dozens of questions and allow me to participate when possible.  And the officers on the bridge answer all the questions and are very welcoming and generous with sharing information and their amazing views!  Carrie and the kitchen crew make 3 amazing meals a day, and I’ve made some new workout buddies to try to stay healthy with all this wonderful food!  The visiting scientists have been very nice about answering all my questions about bathymetry and geology.  It’s great when you are writing and studying about geology to be able to turn around and ask a geologist a question!  

I can’t believe how well I sleep on a ship!  The ship is constantly rocking and for this teacher at sea, and for me, that means some seriously deep sleep.  One thing I learned is to make sure all my belongings are secure before I go to bed.  If you leave something unsecured, chances are they will be banging around in the middle of the night or get tossed off a shelf (not the best middle of the night surprise!).  My room is very dark at night and I really don’t hear anything beyond the noise of the engines.  You can barely hear the foghorn from my area towards the back of the ship which is lucky since those sleeping in the front of the ship could hear it all night!  (Those friends look a little weary today.)  I have to set an alarm, or I will just keep sleeping with the constant rocking motion that is so relaxing!  Only 3 more nights of good ship sleep for me!

Linda Kurtz
The fog horn sounds every 2 minutes when the conditions are, you know, foggy!

Following the excellent tutelage of the NOAA officers, hydrographers, and USGS scientists, it’s exciting to look at the screen in the hydrography lab and start a conversation about features of the sea floor that we are seeing (or seeing in detail) for the first time.  On this mission, there have been new faults, mud volcanoes, and underwater canyons discovered.  The science is so fascinating and so little is known about the research being conducted aboard Fairweather.  I honestly had to “Google” the terms I am now so familiar with like Hydrographic survey, multi beam echo sounders, bathymetry, water column data, just to name a few. 

That’s the thing about science that has been reinforced being a Teacher at Sea, no matter how much you think you know about the earth, you learn just how much we don’t know yet, and we’re just beginning to realize the vast amount that is left to discover. 

Did You Know?

-The ocean covers 71% of the earth’s surface, but we actually know more about the surface Mars than the Earth’s ocean floor- (Credit-Peter Dartnell)

-The Juan de Fuca Plate is part of the famous Ring of Fire, a zone responsible for volcanic activity, mountainous regions, and earthquake activity.

Question of the Day:

Do you know how many tectonic plates there are?  Did you know they are all constantly moving? 

Challenge Yourself

Can you name the Earth’s major tectonic plates?  Can you find on a map the Pacific and Juan de Fuca plates that we are surveying right now?

Animals Seen Today:

Northern Fur Seal