Concerns about tsunami across the Pacific were slowly abating on Sunday, following a massive underwater volcanic eruption the previous day in Tonga that prompted residents on the South Pacific island country to evacuate, but the extent of the damage remains unknown.

As communication with Tonga remained significantly cut off, neighboring countries were trying to discover the extent of damage or casualties. New Zealand Prime Minister Jacinda Ardern said in a news conference that communication due to the eruption has been difficult.

A person looks out to sea from higher ground on the morning of Jan. 16, 2022, in Ishinomaki, Miyagi Prefecture in northeastern Japan after a tsunami advisory was issued in the early hours. (Kyodo)

A volcano about 60 kilometers north of Tonga's capital of Nuku'alofa erupted Saturday, with the entire island nation reportedly hit by tsunami as high as 80 centimeters. Other Pacific islands, the United States and Japan also observed tsunami, but there have been no reports of major damage or casualties.

Tonga is a nation of about 170 islands, of which 36 are inhabited. It is home to about 107,000 people, and as of October 2020, there were 35 Japanese residents.

Ardern reportedly said the undersea cable has been impacted, and New Zealand officials are trying to establish what was needed.

Tsunami of about 1 meter reached New Zealand, which is near Tonga, and more than 1 meter for Pacific islands such as Vanuatu, as well as Chile.

In Alaska and California, tsunami waves of more than 1 meter were observed, according to the U.S. National Oceanic and Atmospheric Administration. There have been no major injuries reported in the United States.

Tidal waves were also observed along Japan's Pacific coast in southwestern islands including Amami Island, as well as in Iwate Prefecture in the northeast which was hit by the 2011 tsunami.

In Japan, its weather agency issued tsunami warnings and advisories for the Pacific coast from Hokkaido to Okinawa, but these were all lifted on Sunday. A 100-year-old woman fell while evacuating for higher ground in Amami, but no major injuries have been reported so far.

Nearly 230,000 people in eight prefectures -- Aomori, Iwate, Miyagi, Chiba, Tokushima, Kochi, Miyazaki and Kagoshima -- were asked to flee from the seaside, according to the Fire and Disaster Management Agency.

Train, air and maritime transport services were also affected, with 27 Japan Airlines domestic flights including to and from Amami canceled. Some ships in Kochi Prefecture, western Japan, were found to have capsized.

A 1.2-meter tsunami was observed in the city of Amami shortly before Saturday midnight, while a 1.1-meter tsunami arrived in Iwate Prefecture early Sunday.

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Japan's Pacific coast hit by tsunami after Tonga eruption