7.3 Mag Quake Hits Alaska, Tsunami Warning Issued

A magnitude 7.3 earthquake struck the Alaska Peninsula on the afternoon of July 16, briefly triggering a tsunami warning for the state's southern coast as communities were ordered to move inland to higher ground.

The earthquake was recorded at 12:37 p.m. local time, southeast of Sand Point, a community located on Popof Island in the Aleutian Chain, according to the U.S. Geological Survey. The Alaska Earthquake Center said the quake was "felt throughout the Alaska Peninsula and southern Alaska."

The National Oceanic and Atmospheric Administration initially issued a tsunami warning for the majority of the Alaska Peninsula, spanning into the southernmost part of Alaska's mainland toward Anchorage.

The alert was later downgraded to a tsunami advisory by 1:50 p.m. local time. The tsunami advisory was in effect for coastal areas from Kennedy Entrance, about 40 miles southwest of Homer, to Unimak Pass — a distance of about 700 miles, according to the Alaska Earthquake Center.

Impacted cities include Cold Bay, Sand Point, and Kodiak, the Anchorage National Weather Service shared on social media on July 16. Authorities warned of potential dangerous coastal flooding, and residents were advised to move inland and to higher ground.

By about 2:43 p.m. local time, the National Tsunami Warning Center said the advisory was canceled for the coastal areas of Alaska.

"Tsunami cancellations indicate the end of the damaging tsunami threat," the National Tsunami Warning Center said in an update. "A cancellation is issued after an evaluation of sea level data confirms that a destructive tsunami will not impact the alerted region, or after tsunami levels have subsided to non-damaging levels."

Multiple aftershocks recorded near Sand Point

A major earthquake, capable of causing "serious damage," is considered to have a magnitude between 7.0 and 7.9, according to Michigan Technological University. Only about 10 to 15 earthquakes of this caliber are reported each year.

The Alaska Earthquake Center said the magnitude 7.3 earthquake was recorded about 55 miles south of Sand Point and was located at a depth of about 9 miles. The center noted that the magnitude and location "may change slightly" as additional data are received and processed.

Following the major quake, the USGS recorded multiple aftershocks near Sand Point, including a magnitude 5.2 earthquake about 66 miles south-southeast of the community.

"So far, there have been at least 20 aftershocks for the M7.3 earthquake south of Sand Point," according to the Alaska Earthquake Center. "Five of them have been above magnitude 4."

What do tsunami alerts mean?

The National Weather Service said tsunami messages are issued by the tsunami warning centers to alert local authorities and the public of a possible tsunami. There are four levels of tsunami alerts, according to the weather service:

• Tsunami Warning: "Take Action—Danger! A tsunami that may cause widespread flooding is expected or occurring. Dangerous coastal flooding and powerful currents are possible and may continue for several hours or days after initial arrival."

• Tsunami Advisory: "Take Action—A tsunami with potential for strong currents or waves dangerous to those in or very near the water is expected or occurring. There may be flooding of beach and harbor areas."

• Tsunami Watch: "Be Prepared—A distant earthquake has occurred. A tsunami is possible."

• Tsunami Information Statement: "Relax—An earthquake has occurred, but there is no threat or it was very far away and the threat has not been determined. In most cases, there is no threat of a destructive tsunami."

Was Anchorage impacted by the tsunami alert?

The Anchorage Office of Emergency Management said in a social media post that the tsunami alert, which Alaska residents may have received on mobile devices, is not a threat to the capital city.

"This message was in response to a large magnitude earthquake southwest of Anchorage and the message zones overlapped," the office wrote.

No threat for Hawaii and Washington state

The Office of Emergency Management of Hawaii's O'ahu released a statement on X, reassuring residents that there is no tsunami threat to the island.

In Washington state, officials said the earthquake prompted them to examine whether it would impact the state's coastlines. Data from tsunami buoys showed there was no danger for the state, the Washington Emergency Management Division said on X.

"We have now been told there is NO DANGER for Washington state from this earthquake in Alaska," the Washington Emergency Management Division said. "Scientists had to wait to examine the wave heights arriving at DART tsunami buoys -- and those sensors now indicate there is NO DANGER for our coastline."