Geologic Features of a Seamount Application1
Your Objective
Use depth and angle (tilt from side to side) data of the seafloor, along with maps of the seafloor from the Axial Seamount in the Northeast Pacific Ocean (Cabled Axial Seamount) to determine if there are relationships over 4 days in 2015.
- Make a prediction about what kind of changes or patterns in seafloor depth, angle, and overall shape you may observe over time.
- Compare patterns in the data below to determine what and if there are relationships over time.
Include datasets:
Data Tips
When the site loads, you are able to compare the bathymetry (map of seafloor) in September 2013 or July 2015. You also can see the seafloor depth and angle (tilt) in the X (east-west) and Y (north-south) directions four days in April 2015 at the Axial Seamount.
You can interact with the map by:
- Using the green slider at the center of the map to move between the Sep 2013 and Jul 2015 maps as you are interested.
- Selecting the category buttons below to "Show only before" or "Show only after."
You can interact with the graphs by:
- Zooming in and out of the data to look at different time scales that interest you by changing the width of the highlighted section of the bottom graph (it loads with all of the data highlighted).
- Selecting a different part of the time series to explore the data in ways that interest you by moving the highlighted section of the bottom graph to the right or left.
- Adding a different location of instruments at the seamount by selecting the other locations.
Note - Tilt values are in microradians. One microradian is the amount of angle you'd get if you lifted one end of a straight line that is 1 km long by 1 mm.
Questions for Thought
- Across what depth range is the seafloor around the Axial Seamount?
- Across what time period are you able to observe depth and angle (tilt from side to side) data of the seafloor in these graphs?
- What is the first day there are data?
- What is the last day there are data?
- In what direction (North, South, East, or West) is the angle of the seafloor when there is a negative X-tilt? A negative Y-tilt?
- In general, what changes did you observe in the seafloor shape from before (Sep 2013) and after (Jul 2015) the event?
- What changes or patterns did you observe in seafloor depth over this time period at the Axial Seamount?
- When did you see these changes or patterns?
- What is your evidence?
- What changes or patterns did you observe in seafloor angle over this time period at the Axial Seamount?
- When did you see these changes or patterns?
- What is your evidence?
- What questions do you still have about why the depth, angle, and shape of the seafloor changes over time?
Background Information
Click on the images below to learn more about where and how the dataset above was collected.
Additional Resources
- Want to convert microradians into degrees? You can use an online unit converter.
- Learn how the Bottom Pressure and Tilt sensor measures changes in the seafloor in this Video Blog #9 "Pressure Measurements" from the NOAA Earth-Oceans Interaction Program 2015 cruise to Axial Seamount.
Dataset Information
The data for this activity was obtained from the following Bottom Pressure and Tilt instruments on the Cabled Axial Seamount array:
- Central Caldera (RS03CCAL-MJ03F-05-BOTPTA301)
- Eastern Caldera (RS03ECAL-MJ03E-06-BOTPTA302)
- International District Vent Field 2 (RS03INT2-MJ03D-06-BOTPTA303)
The above datasets were downloaded from the OOI data portal and downsampled to simplify the datasets for plotting. Special thanks to William Chadwick for assistance in the processing these data. For more information about these data and past events, please check out NOAA PMEL's site on Bottom Pressure and Tilt instruments at Axial Seamount.