Seafloor Mapping in Solar

By: Cem Ozcan

The OCEAN
The ocean is a part of the biological component of the earth in which living creatures like man depend greatly on its resources.. The ocean covers about three fourths of the earth land or about 71% from all of its corners. Its floor has been the favorite expedition venue of marine Biologists and other scientists to discover life beneath it. Oceanography experts are, likewise, very interested in exploring the ocean floor to study the trenches, basins and the rest of its features. (Encarta)

NOAA
To address the growing needs for oceans and atmosphere studies, the National Oceanic and Atmospheric Administration (NOAA) was created. NOAA is mandated to explore and document the global oceans for proper management, use and formulate preservation steps for all the living resources. It is also the agency that protects the marine life by conducting different studies and disseminating the data to be used by different government agencies. The data that NOAA gathers is crucial for natural disaster preparation from state to federal level, thus avoiding what happened in New Orleans. (NOAA Homepage)

Part of the NOAA is the National Ocean Services. This office is in charge of preparing the charts and surveys they gather and at the same time guarding for any tidal and seismic activity within their area of responsibilities. The National Weather Service, is also a critical component of NOAA that provides weather forecasts to the general public that serves as warnings for possible incoming disasters. There are other offices within the NOAA that monitor the ecological balance of both the earth and its atmosphere.
Scientists for both the government and private societies have always been amazed with the mysterious composition of the ocean floor. This have led to several deep sea exploration of life under the deep sea and conduct the mapping of the ocean floor to have a better understanding of its shape, characteristics, measures and other relevant information. The satellite technology is also used on the study of the ocean floor composition and topography by the use of techniques called the satellite mapping. This technique measures the ocean level to come up with the data that could estimate its entire composition.

To further enhance this type of study, different techniques have been employed for the past five decades from theory to the use of deep sea equipment SONAR. The SONAR measures the depth of the ocean floor, Seismic Technique that charts the solid characteristics of the ocean floor. Even with the available latest gears and techniques, scientists believe that it will take many years before man maps out the entire ocean floor of the earth.

SONAR
SONAR is short for Sound Navigation And Ranging, which determines and detect ocean floor depth by using the reflection of the underwater sound waves. This technique is used similarly with the radar system that is based on the theory about the reflection of radio waves in the open space or air. A regular set of a sonar system creates an ultrasonic pulse using a deep sea radiating equipment coupled with a specialized hydrophone that reflects pulse from possible barriers or approaching submarines. (Encarta)

During the early years of the SONAR Technology particularly during the last two world wars, British and Americans had different names for such deep water detecting system. In the United Kingdom, British sailors call it the ASDIC from an investigation group of this technology known as the Anti - or Allied Submarine Detection Investigation Committee.
Here in the United States, the word SONAR is the name used for all kinds of underwater detecting system by the Navy during the world wars. These were widely used to sink enemy vessels or submarines. In 1948, the North Atlantic Treaty Organization or NATO decided that a single name must be used for their country members when referring to deep water detecting system during military operations. The word SONAR was the most popular among members of the NATO and it was then agreed that it will be the official name for this technology. This was also easily adopted by other countries outside Europe. Today, the word SONAR is the word used worldwide for all deep water detecting system by both the Navy and Civilians. (NATO)

There are actually two types of SONAR systems known as active and passive. The active SONAR produces a ping sound in the ocean which travels using the sound waves and goes back and determines if it hit something. The ping pulse generated by the active sonar determines the location and range of any objects along its path. This type of sonar has also been an issue with marine life activists because they believe that causes of beached whales today is due to this technology. (Encarta)

The passive sonar procedure is that operators listen carefully to different sounds like vessels within its range. During war, the navy employs this technique for obvious reason, but limits its features because operators need to switch to active mode to generate the range information of the enemy vessels or sea mines.

SIDE SCAN SONAR

Side scan sonar is a scientific marine geophysical technique under the sonar system that produces good images of large parts of lakes, sea floor including deep rivers. It also provides a wide array of information for the charting of nautical measurements and identifying underwater barriers or objects. The side scan sonar is widely used by experts when surveying for the topography and studying the marine life of the deep sea. Side Scan Sonar is a marine geophysical technique that is used to image or "see" the ocean floor, lakes or rivers bottoms. (Sidescan)

The Side scan sonar system transducer is housed in a tow-fish structure that is towed by the vessel while scanning the sea floor. This process reflects the acoustic returns viewed on a small screen inside the vessel. Typically, the side scan sonar operations usually go as wide of 60 to 160 feet wide for about 2 miles an hour. The capability of side scan sonar may go beyond this usual coverage depending on the scope of use or study being conducted. (Sidescan)

For shallow waters, the installation of the side scan system is different from the deep or open sea study or searches. In this application the transducer connected to the boat can be controlled when operating on this kind of waters.

In shipping oil and gas industries the side scan sonar plays a key role in keeping its paths safe both for the ships and crews, including the navy by providing valuable information of the seabed or ocean floors underneath them. It also provides real time maintenance or investigations on the status of pipelines and cables constructed on the ocean floor.
Side scan information is generated along with bathymetric soundings and sub-bottom data that reveals shallow composition of the sea floor. This technique is widely accepted procedure commonly used by scientists, advanced fishermen, ocean engineers and the navy to gather information and use it for studies including intelligence gathering.
It is said that the side scan provides very high resolution images using high frequency of sound waves ideal for surveying large areas of seafloors. The frequencies used for the side scan sonar is anywhere from 100 kilohertz to 500 kilohertz. The use of higher frequencies for this type of sonar scan results to better images but provides less range.

Multi Beam Sonar
The process of the multi-beam sonar is different from the side scan sonar techniques. It uses the sound energy to define the ocean floor by measuring the time of the signal that it generates to travel from the transmitter down to the ocean floor and back again.
A multi-beam sonar equipment is usually attached to the vessel's body and rely heavily on time measurement. The data that it gathers depends on the depth of the water it actually surveys to get the data. This procedure provides good quality of images even for small objects of about 1 diameter in size. This type of sonar is also capable of determining if an object is hard solid or a soft mud which also provide data of the over all composition of the ocean floor.

Submarine Cables

The use of Transcontinental Fiber Optic Cable Route is widely used today with the availability of the modern communications in place. It is also sometimes referred to as submarine cables because it is submerge just on top of the ocean floor across the world. ( Fiber Optic ). These submarine cables are credited for the success of today's communication technologies from voice, video and the internet. About 90% of all the communications in and out of the United States and North America have been made possibly by these cables.

Before any work is started on Transcontinental Fiber Optic Cable Route projects, a great deal of time and study is undertaken by contractors. These include the ocean floor survey that provides important data like depth and the characteristics of the seafloor where cables would be laid. (Fiber Optic )

The use of the multi beam sonar system for the submarine cable projects may not be at all ideal because its feature is mainly on the depth measurement. Its disadvantage is that as the surveys get in to deep water, the data it yields becomes less accurate. Therefore, use of the side scan sonar is the ideal for any mapping of the ocean floor as preparation for any transcontinental fiber optic projects. Side sonar provides wider information when it is used for studies or surveys of the sea floor in any parts of the earth. The important feature of the side scan sonar is its ability to provide a clear picture and scan the status of the underwater cables and for security purposes as well.

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