We are now entering another phase of our expedition – high resolution imaging of the mid-Atlantic ridge, the place where tectonic plates are born! This is so exciting because we are imaging the ocean floor in a never seen before detail. The images come in near-real time as we sail north – south across the ridge. The lab is always buzzing with people day and night who stop by simply to look and wander at the amazing structure of the oceanfloor. It is like having a closer look at an alien planet. The ocean is about 5000 meters deep, however, near the ridge it abruptly reduces to about 2000 meters. Some of the underwater mountains are as high as 3000 meters and the steepest walls are about 1800 – 2000 meters high!
The technology that enables us to image these features at a high resolution is based on the simple principle of echoes. An instrument called a multibeam echosounder, that is positioned at the bottom of the ship, emits a sound signal. This signal travels through the water, bouncing off objects and features on the seafloor and are recorded by the instrument. The time that a single beam of sound takes to travel from the ship to the bottom of the ocean and back is recorded. In a previous post we talked about measuring the sound velocity using an instrument called Sound Velocity Profiler. We use this sound velocity information convert the travel time of sound to depths. The longer an echo takes to arrive back, the deeper is the ocean! Using state-of-the-art tools, we process and visualize the oceanfloor in 3D. Here are some magnificient and breath-taking images of the mid-Atlantic ridge.