BathymetryBathymetryObjective: To learn and Objective: To learn and distinguish some basic distinguish some basic bathymetric (sea floor) bathymetric (sea floor) features and contour features and contour

them.them.

BathymetryBathymetry The sea floor is not flatThe sea floor is not flat

MethodsMethods

• Lead line –Lead line –– Old fashioned, lots of errorsOld fashioned, lots of errors

• Sonar –Sonar –– Better, but still some errorsBetter, but still some errors

• Side Scan Sonar –Side Scan Sonar –– Best – multiple passes can create 3D Best – multiple passes can create 3D

imagesimages

GLORIAGLORIA

Sandy bottom off Massachusetts disturbed due to a Hurricane: ripplesare beginning to reform

Submerged Chevette missing hood

Small private helicopter crash site

Fish

High Resolution Imaging High Resolution Imaging

Notes on Procedure - Notes on Procedure - Exercise 1Exercise 1• Be sure to hold down the landform when Be sure to hold down the landform when adding water or it will float up and move adding water or it will float up and move around.around.

• Draw lightly with the crayon, because every Draw lightly with the crayon, because every mark has to be erased at the end.mark has to be erased at the end.

• Wait until after you have marked each cm Wait until after you have marked each cm increment on the landform by adding water increment on the landform by adding water to draw the two dimensional contour using to draw the two dimensional contour using the dry erase marker and acetate sheet.the dry erase marker and acetate sheet.

• Label your contours and copy onto a sheet of Label your contours and copy onto a sheet of paper using the overhead projector or paper using the overhead projector or another light piece of paper. another light piece of paper.

Notes on Procedure – Notes on Procedure – Exercise 2Exercise 2• Take all measurements except row Take all measurements except row

10 using the FINE chart10 using the FINE chart• Transfer your measurements onto Transfer your measurements onto

the COARSE chartthe COARSE chart• Plot the coarse, then the fine in Excel Plot the coarse, then the fine in Excel

(OR contour by hand)(OR contour by hand)• Try changing the scale to see how Try changing the scale to see how

the details change. the details change.

WITHOUT SCALE: IS IT A BASIN OR A GUYOUT?

Vertical ExaggerationVertical Exaggeration

PracticePractice