This is a buoy from the Deep-ocean Assessment and Reporting of Tsunamis (DART®) system, which can detect tsunamis as small as 1 cm and report them in real time.

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A Deep-ocean Assessment and Reporting of Tsunamis (DART®) buoy displayed atop a metal case, which serves as an anchor. The case has a special rope coiled inside that unspools automatically when deployed. The case also has the actual pressure detector (or tsunameter) and the acoustic modem to send the data to the buoy. (Image credit: NOAA Heritage)

When deployed, the buoy floats on the ocean’s surface, linked to a tsunameter on the ocean floor that transmits data to the buoy for relay to a ground station via Iridium satellite communication system.

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Deep-ocean Assessment and Reporting of Tsunamis (DART®) - Easy to Deploy (ETD) buoy system (Image credit: NOAA)

The second generation of DART® buoys features two-way communications, so that ground stations can pull tsunami data at any time.

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Graphic showing the entire DART® II system used for tsunami forecasting. (Image credit: NOAA)

There are currently 74 DART® buoy systems around the world, most of them near coasts in the Pacific Ocean.

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Screenshot of interactive Deep-ocean Assessment and Reporting of Tsunamis (DART®) buoy map found at https://www.ndbc.noaa.gov/. (Image credit: NOAA)
 
This network of buoys helps create more accurate tsunami forecasts that can be used to issue watches, warnings, or evacuations.
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