USGS: Monterey Bay Underwater Map

USGS Monterey Bay National Marine Sanctuary Project
Underwater Image Map of Monterey Bay

Noisy Fish
Mowin' the Lawn
- Sonar Strips are like Jigsaw Puzzle Pieces!
Seafloor Maps

Noisy Fish
	The image to the left shows a side-scan sonar fish, which is an instrument that makes noise and listens for the noise to echo back from the seafloor. By measuring how long it takes for the sound to return and how loud it is when it echos back, an image* can be made of the seafloor! The fish is pulled in the water behind a ship.
It is very dark in deep water because there is little or no light. Humans need to use a special kind of "camera" that uses sound rather than light to see the ocean floor.
Sonar is also used by submarines to see where they are going and to see other submarines and things swimming around in the ocean. Dolphins and whales also use sound to help them see and get around in ocean waters! Bats "see" in the dark using sound too, only it's called echo location! Bats and dolphins make clicking sounds just like the sonar fish does to measure how far away an object is. [ TOP ]
Mowin' the Lawn As the sonar fish moves along in a straight line behind the ship, it makes sound images of the seafloor beneath it. Since the ships moves in long, straight lines, the images it collects are long, straight strips. Fun Fact: The ship moves back and forth in long, straight lines to cover an entire area. This reminds the people on the ship of mowing a lawn... so they call it Mowing the Lawn! A digital (computerized) sonarmosaic of the seafloor covering Monterey Bay was made by combining a lot of these strips of images, like a jigsaw puzzle. The image strips show a piece of the seafloor 600 to 1500 feet wide and several miles long. When the strips are puzzled together, the image they make is called a mosaic. Click here to see a sonar strip image and learn more about how sonar mosaics are like big jigsaw puzzles! Below are some sonar image maps of the seafloor under the water of Monterey Bay! [ TOP ]

Monterey Bay Region Seafloor Image Maps

Click on thumbnails image below to zoom in on the mosaics.
Side-scan and Multibeam are words that describe different kinds of sonar fish.

Can you find Monterey Bay, California on a map or globe?

Monterey Bay
Image Map

This image is a mosaic of two sonar mosaics and an image of the land. The land image is called a shaded relief and is computer generated from a digital elevation model(topography).

(153 k)

Figure 2a: Digital Side-scan Sonar Mosaic
Updated 5/28/98
(102 k)

Figure 2b: Digital Multibeam Sonar Mosaic
New - 5/28/98
(154 k)
Back to text

[ TOP ]

Back to Cool Stuff to See!

To TerraWeb For Kids Home!

U.S. Department of the Interior | U.S. Geological Survey | Jobs
Home | Search | Disclaimers & Privacy Web Rings
Send comments to webman@TerraWeb.wr.usgs.gov
URL:
Last Modified: Thu Oct 31 15:08:21 MST 2002