A 7.9 magnitude earthquake struck off the Alaskan Aleutian Islands on Monday, causing the U.S. Geological Survey and National Tsunami Warning Center to issue a tsunami warning.

Not long after the warning was issued, it was downgraded to advisory and the waves are expected to be maybe a foot in height and will reach Saint Paul and Unalaska, the Los Angeles Times reports.

The first waves created by the deep underwater earthquake were little over half a foot tall and have reached some cities, including Shemya, but there hasn't been any damage at the Air Force Alaska command, spokesman Sgt. John Gordinier said.

When the tsunami warning was initially released, some residents in Adak evacuated, according to Reuters.

The National Weather Service in Alaska tweeted shortly after the quake hit that people near the coast in Adak began moving towards higher ground because water was pulled out of the harbor.

Director of the Alaska Earthquake Center, seismologist Mike West, commented that seismometers all across the world would be registering the aftereffects of the earthquake for a day. "When you've got an earthquake that big, it rings the Earth like a bell."