There Are Over 300 Undiscovered Meteorite Impact Craters on Earth, Geologists Claim
It is essentially common knowledge in this day and age that phenomena in space can play a significant role in shaping life on earth. Meteorites have perhaps played the most crucial role, as they have struck the earth many times over the course of the planet's existence. Most notably, an enormous collision of a meteorite with Earth at the end of the Cretaceous period is thought to have caused the extinction of the dinosaurs. Now, geologists are attempting to calculate just how many meteorite impact sites are present on the surface of the earth that may yet be undiscovered.
Geologists Dr. Stefan Hergarten and Dr. Thomas Kenkmann from the University of Freiburg have published the first study that estimates just how many meteorite craters there should be on Earth's surface. According to the results of a probability calculation, published in Earth and Planetary Science Letters, a total of 188 craters have been confirmed so far, and 340 more are still awaiting discovery.
This may seem like quite a lot, but compared to the 300,000-plus craters present on Mars, 340 is almost underwhelming. Although meteorites are not less likely to crash on Earth than on Mars, Earth's surface changes much more rapidly, so it is much more likely that a crater will be eroded to the point that it's undetectable. Hergarten told Science Daily, "The main challenge of the study was to estimate the long-term effect of erosion, which causes craters to disappear over time."
Aside from erosion, the other fact that determines a crater's lifespan, and therefore its probability of detection, is its size. Obviously, large craters are much easier to spot than smaller ones, but they are also much less likely to exist, as large impacts are much rarer than small impacts. "A surprising, initially sobering finding we made was that there are not many craters of above six kilometers in diameter left to discover on the Earth's surface," Hergarten stated. It is also much more difficult to find large craters, as they are more likely to be covered in deep sediment.
Although they may be difficult to find, the researchers estimate that 90 craters with a diameter of one to six kilometers and a further 250 with a diameter of 250 to 1000 meters are yet to be discovered by scientists. Large craters, in particular, will most likely be hidden from detection, but at least we now know what exactly is buried underneath Earth's changing surface.