Mysterious Ocean Craters Off the Coast of Iceland Defy Scientific Explanation

Geologists in Iceland recently discovered seven craters in the seabed off the coast of the northern city of Dalvík. Experts aren’t sure what caused these craters, but they suggest they may be left over from anti-submarine weapons used in the World Wars. 

Iceland Geosurvey (ÍSOR) is a state-owned nonprofit that specializes in geothermal and hydropower research and development. While mapping Iceland’s coastal seabed, ÍSOR researchers stumbled upon something strange: seven inexplicable underwater craters. The finding was revealed by ÍSOR at its annual meeting, Iceland Review reported. In addition to ÍSOR ocean mapping, the craters' existence is also backed by data from the Marine Research Institute, the Coast Guard, and measurements from a number of Icelandic and international fishing ships, Icelandic news agency RUV reported.

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Researchers aren’t sure what caused the craters, but they think they are fairly new and are man-made.

03_13_ocean The craters were found not far off the coast of Iceland. Joe Raedle/Getty Images

“We have not found any clear reasons for them,” said geologist Ögmundur Erlendsson, RUV reported. “Whether they are natural or man-made. We think it's because of a deep bomb from the war years."

Anti-submarine weapons were popular in the World Wars. These bombs weighed 200 pounds or more and caused large explosions designed to compromise submarines. At close range, the shock from these bombs could cause serious damage to the submarines, but close detonations were difficult, The Pacific War Online Encyclopedia states.

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In order to fully understand the craters, scientists may have to dive down and personally explore these ocean floor markings, RUV reported.

Not all underwater craters are man-made. Some are the result of a buildup of natural gases. For example, off the coast of Norway, unstable methane can build up and cause violent explosions. This can result in the formation of multiple giant creators on the ocean floor, IFL Science reported.