If you happen to be a bathymetry buff, we've got an update that you'll be excited about (and if you're not, I hope you will be one by the end of this post). Most of the underwater terrain currently featured in Google Earth comes from the low-resolution US Navy/NOAA/SIO global grid. They're able to predict what the seafloor looks like using an extrapolation of water surface heights to estimate undersea mountains and canyons, based on radar data collected by satellite (if you're curious about this process, you can read Smith and Sandwell's more detailed explanation here). For most of the sea, that's all that's available. But a small part of the ocean has higher-resolution data available, based on echosounding sonar from ships, and it's now available in Google Earth.

Several organizations have provided their ship-collected data for publication in Google Earth to improve our undersea maps. The Center for Coastal and Ocean Mapping - Joint Hydrographic Center, has shared large swaths of underwater depth data collected from their expeditions north of Pt. Barrow, Alaska into the Arctic. The Living Oceans Society has shared their surveys off of the west coast of British Columbia, Canada, so you can now zoom around the Oglala seamount:

The California State University at Monterey Bay has collected high-resolution underwater terrain data for the entire California coast out to three nautical miles. We've published their data north and south of San Francisco Bay down to Ano Nuevo, where you can see the underwater ridges that elephant seals must navigate.

You can now also explore large undersea areas newly published from the Monterey Bay Aquarium Research Institute (MBARI), including our highest resolution underwater depth data featured to date: 1-meter terrain collected by MBARI’s Autonomous Underwater mapping Vehicles in Monterey Bay Canyon (see screenshot below), which is an underwater canyon larger than the Grand Canyon nestled between Santa Cruz and Monterey, California. MBARI has also shared ship echosounding maps that they've collected on the Davidson seamount, the Rodriguez seamount off of Santa Barbara, and terrain along the Juan de Fuca Ridge, as well as data collected off of the Oregon coast, from Beaver basin to the Heceta bank.

Photo caption:
The MBARI Autonomous Underwater Vehicle (AUV) being launched from the Research Vessel Zephyr and one underwater. The MBARI Mapping AUV is a torpedo-shaped vehicle equipped with four mapping sonars that operate simultaneously during a mission. The sonars are a swath multibeam sonar, two frequencies of sidescan sonars, and a sub-bottom profiler. The multibeam sonar produces high-resolution bathymetry (analogous to topography on land), the sidescan sonars produce imagery based on the intensity of the sound energy's reflections, and the subbottom profiler penetrates sediments on the seafloor, allowing the detection of sediment layers, faults, and depth to the basement rock. All components are rated to 6000 m depth. The vehicle is launched on programmed missions and runs on its own battery power until it returns to the ship, as programmed, for recovery. The mapping AUV was christened the D. Allan B. in honor of MBARI's long-time Board member Dr. D. Allan Bromley of Yale University, who passed away in 2004.

Download this new undersea tour and open it in Google Earth to explore for yourself. Remember that only 5% of the world’s oceans have been explored, so much remains to be discovered.
We continue to publish new data in Google Earth, so check back. We thank all of the ocean exploring groups who have shared their data and welcome new contributions.