Dive Location

The Earth's longest mountain range is underwater. Called the Mid-Ocean Ridge system, it is over 56,000 kilometers (35,000 mi) long and snakes around the globe like a zipper or the stitching on a baseball.

The East Pacific Rise is part of this system. This ridge is in a geologically active area, where the Earth's tectonic plates are moving apart and new seafloor is being born, giving rise to hydrothermal vents, volcanoes and earthquakes.

The East Pacific Rise was discovered during the Challenger expedition in 1875.Over 100 years later, in 1979, the submersible Alvin made its first trip to the East Pacific Rise and revealed "black smokers" spewing super-heated water.

vent

The East Pacific Rise is one of the fastest-spreading sections of the Mid-Ocean Ridge system. While many tectonic plates move about as fast as your fingernails grow, the plates here move an average of 14.2 cm (5.6 inches) each year.

On October 20, 2002 a research team led by U of D scientist Craig Cary will set sail on a 17-day expedition exploring the hydrothermal vents of the East Pacific Rise.

Click on the red stars and Alvin to find out more on the key stops of our journey to 9 degrees North.

The Pacific Ocean is the largest body of water on Earth. It covers about a third of the world's surface. This great ocean is larger than the total lland area of the world. It's just slightly less than 18 times the size of the United States. To learn more,

sexton How do mariners find their way on the high sea? Modern-day sailors rely on several high-tech tools such as the Global Positioning System (GPS), a satellite-based radio navigation system initiated in 1973 by the U.S. Department of Defense for military applications. Today, the GPS system is widely available for civilian use. It can provide users with accurate information about their location at any time, in any weather, anywhere in the world.

Twenty-four GPS satellites circle the Earth twice a day, transmitting signal information. GPS receivers compare the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. By taking distance measurements from several more satellites, the receiver can compute latitude, longitude, altitude, and time.

The U.S. Coast Guard requires mariners to know celestial navigation to operate a vessel more than 200 miles offshore. By using a traditional navigational tool such as a sextant (represented in the graphic above), mariners can determine their location by measuring the vertical angles between two or more stars and the horizon line. This sighting process is called "shooting a star."

Check out some of the recent earthquake activity near our Extreme 2002 dive location.