The ocean might be important to us than the moon. We use the ocean for many things. We need the ocean for food and minerals. Because of this, it is important to find out as much as we can about the ocean.
We know more about the shoreline than about any other part of the ocean. Over a period of time, the ocean changes the shoreline. The waves and the tides carry water up onto land. This action of waves and tides sometimes break up the land. Sediments are carried away. The heavier pieces of sediments fall to the bottom first.The lighter pieces of sediments are carried out farther by the water before they settle to the bottom.
Sediments pile up near the shore, the ocean starts to become deeper. Here the ocean floor becomes steeper. This is the continental slope. The continental slope is the area after the continental shelf where the ocean becomes deeper.
If the edge of a continent were lifted up, the continental shelf could be raised out of the water. The shoreline would bewider and flat with a sandy beach. If the edge of a continent were dropped, the ocean would move inland. Then the shoreline would be very rough. There would be very little, if any, beach.
Ocean mapping is made possible through indirect methods. Oceanographers use echo sounding, sonar, radar, and seismographic surveys. Vibration such as sounds is set down from the ocean surface. The vibrations are then reflected from the ocean bottom at the same angle they are received and are recorded at the surface.
Ocean topography has been determined though sonar detection. Seismograph surveys are obtained by sending off vibrations from a gas or air gun aboard a ship. Another ship does the recording of the arrival time of the sound waves. Since seismic vibrations pass through soil layers of different densities, the vibrations received will travel at different speeds. Through these differences, the survey will indicate the kind of soil present and surface features of the ocean floor.