New Maps Reveal California’s Sensational Seafloor Geography

AN UNPRECEDENTED EFFORT to map the seafloor bordering California’s coastline has produced some of the most detailed, beautiful and useful maps of an underwater landscape ever made. 

No fewer than 18 state and federal agencies and institutions led by the US Geological Survey banded together to make these maps. A staggering amount of work went into the California Seafloor Mapping Program, and the results are impressive.

“Nowhere else in the world are people pursuing comprehensive seafloor mapping at this scale,” said USGS geologist Sam Johnson, the agency’s lead scientist on the project. “It’s really unprecedented globally.”

The maps could be important for studying things like navigation safety, coastal erosion and sea level rise, fisheries, and earthquake and tsunami hazards. The maps have already yielded a ton of new information for scientists, along with a few surprises. For example, in Bodega Bay, the San Andreas fault is actually located about 800 meters away from where it was thought to be.

The scale of the project, started in 2007 by the California Ocean protection Council, is staggering. For 83 blocks of seafloor, each stretching 3 nautical miles from the shoreline, ten different maps are being made of the bathymetry (underwater topography, as seen in the color shaded-relief map of San Francisco Bay at the top of this post), geology, and ocean floor biological habitats. The maps are based on a wide range of data collected since 2007, including swath sonar data, acoustic backscatter, seismic-reflection profiles, seafloor photos and video, and samples of the seafloor sediment. Pretty much the only thing they didn’t use are the Navy’s trained dolphins.

All the data collection and mapping has been completed, and the USGS is in the process of releasing the maps and related reports to the public. Today the maps for the Bay AreaTomales Point, and Drakes Baywere published. A total of 12 blocks have been releasedto date, and Johnson expects the next ten to be available by October.

Read full article HERE.