On a relatively small part of the Pacific Ocean, off the western coast of the United States, there are several thousand indentations of various sizes, the origin of which is not completely clear.
This was reported by scientists at the Monterey Bay Aquarium Research Institute (MBARI).
The larger pits have an average width of 175 meters and a depth of about five meters. Their shape is almost perfectly round.
Over the last few years, experts at MBARI and other organizations have found more than 5,200 such holes, such as smallpox, on an area of approximately 1 300 square kilometers. So far, this is the largest concentration of such sites in North America.
More recently, scientists have been exploring the bottom of California in more detail. The fact is that they want to build a power plant there, but first they need to study the local conditions in detail.
Thousands of small pits or micro-depressions have been discovered using sonars mounted on autonomous submarines. Their width is about 11 meters and the depth is about a meter. Moreover, their shape is not round but oval.
Previously, similar seabed depressions have been found elsewhere in the world, and their origin is mainly due to methane emissions.
However, MBARI researchers find no evidence of this gas in the bottom sediments or in the water in this region.
Sonar data showing sludge bed layers, indicate that these points have been inactive for the last 50,000 years.