The Hawaiian Islands are moving toward the northwest at a rate of approximately 7 to 10 centimeters (about 3 to 4 inches) per year. This movement is caused by the Pacific Tectonic Plate sliding over a stationary "hotspot" in the Earth's mantle. This is roughly the same speed at which human fingernails grow. Over millions of years, this geological process has created the entire Hawaiian archipelago; as the plate moves, the existing islands drift away from the volcanic source and slowly begin to erode and sink, while a new island is formed over the hotspot. Currently, a new undersea volcano named Lōʻihi (or Kamaʻehuakanaloa) is forming about 20 miles off the coast of the Big Island. Scientists estimate it will take another 10,000 to 100,000 years for this new landmass to breach the ocean surface. This constant "conveyor belt" motion means that millions of years from now, the current islands will be located much closer to Japan and the Aleutian Islands than they are to North America.