In this exhibit, we demonstrate how marine geophysicists use sound to explore areas of the Earth that cannot be seen directly. By producing sound waves and recording those waves with an underwater microphone, or hydrophone, we can identify features at the bottom of the ocean and deep inside the Earth. Lamont-Doherty Earth Observatory operates the Research Vessel Marcus G. Langseth, which enables scientists across the United States to collect these data.
The path of a sound wave between where it is created and the microphone recording it depends on the composition and structure of the material that the sound travels through. For example, while sound travels through water at a speed of 3355 mph, it can move through the Earth’s crust at a speed of 14,000 mph! Geophysicists characterize the Earth’s physical properties by measuring the intensity and speed of sound waves that travel through the Earth.