An undersea volcano erupted in spectacular fashion Saturday near the Pacific nation of Tonga, sending tsunami waves crashing across the shore and people rushing to higher ground.
The eruption cut the internet to Tonga, leaving friends and family members around the world on Sunday anxiously trying to find out if there were any injuries and the extent of the damage.
Satellite images showed a huge eruption, with a plume of ash, steam and gas rising like a mushroom above the blue Pacific waters. A sonic boom could be heard as far away as Alaska.
Tsunami advisories were issued for most of the Pacific Rim, including Hawaii, Alaska and the U.S. Pacific coast. The U.S. Geological Survey estimated the eruption caused the equivalent of magnitude 5.8 earthquake. Scientists said tsunamis generated by volcanoes rather than earthquakes are relatively rare.
The Tonga Meteorological Services said a tsunami warning was declared for all of the archipelago, and data from the Pacific tsunami center said waves of 80 centimeters (2.7 feet) were detected.
Rachel Afeaki-Taumoepeau, who chairs the New Zealand Tonga Business Council, said she hoped the relatively low level of the tsunami waves would have allowed most people to get to safety, although she worried about those living on islands closest to the volcano. She said she hadn't yet been able to contact her friends and family in Tonga.
"We are praying that the damage is just to infrastructure and people were able to get to higher land," she said.
Tonga gets its internet via an undersea cable from Suva, Fiji, which presumably was damaged. All internet connectivity with Tonga was lost about 6:40 p.m. local time, said Doug Madory, director of internet analysis for the network intelligence firm Kentik.
Southern Cross Cable Network, the company that manages the connection, does not know yet "if the cable is cut or just suffering power loss," chief technical officer Dean Veverka said.
The Fiji-based Islands Business news site reported that a convoy of police and military troops evacuated Tonga's King Tupou VI from his palace near the shore. He was among the many residents who headed for higher ground.
On Tonga, home to about 105,000 people, video posted to social media showed large waves washing ashore in coastal areas, swirling around homes, a church and other buildings.
A Twitter user identified as Dr. Faka'iloatonga Taumoefolau posted video showing waves crashing ashore.
"Can literally hear the volcano eruption, sounds pretty violent," he wrote, adding in a later post: "Raining ash and tiny pebbles, darkness blanketing the sky."
The explosion of the Hunga Tonga Hunga Ha'apai volcano was the latest in a series of dramatic eruptions.
Earth imaging company Planet Labs PBC had watched the island in recent days after a new volcanic vent began erupting in late December.
Satellite images captured by the company show how drastically the volcano had shaped the area, creating a growing island off Tonga.
"The surface area of the island appears to have expanded by nearly 45% due to ashfall," Planet Labs said days before the latest activity.
Tsunami alert lifted for Hawaii
In Hawaii, the Pacific Tsunami Warning Center reported waves that measured half a meter (1.6 feet) in Nawiliwili, Kauai and 80 centimeters (2.7 feet) in Hanalei. The National Weather Service said there were reports of boats getting pushed up in docks, but the hazard diminished as the morning went on.
"We are relieved that there is no reported damage and only minor flooding throughout the islands," the tsunami center said, describing the situation in Hawaii. The tsunami advisory for the islands was lifted about 11 hours after the eruption more than 4,828 kilometers (3,000 miles) away.
Residents in Hawaii, Alaska and along the U.S. Pacific coast had been advised to move away from the coastline to higher ground and to pay attention to specific instructions from their local emergency management officials, said Dave Snider, tsunami warning coordinator for the National Tsunami Warning Center in Palmer, Alaska.
"We don't issue an advisory for this length of coastline as we've done … but it really isn't an everyday experience," Snider said.
The first waves to hit the continental United States measured about 33 centimeters (1 foot) in Nikolski, Alaska, and 59 centimeters (1.9 feet) in Adak, Alaska. A wave of about 79 centimeters (2.6 feet) was observed in Monterey, California, according to the U.S. National Tsunami Warning Center.
Beaches and piers were closed across Southern California as a precaution. The National Weather Service tweeted there were "no significant concerns about inundation." Strong rip currents were possible, however, and officials warned people to stay out of the water.
On California's central coast, the National Weather Service reported tsunami waves up to 4 feet (1.2 meters) and flooding in beach parking lots at Port San Luis. About 200 miles (320 km) down the coast, the waves were much smaller at Southern California's Seal Beach, according to Michael Pless, the owner of M&M Surf School.
"The waves are looking pretty flat," Pless said. "We're hoping they reopen the beach in a couple hours."
Crowds gathered at the Santa Cruz Harbor in California to watch the rising and falling water strain boat ties on docks. Law enforcement tried to clear people away when big surges started at around 7:30 a.m.
About an hour later, a surge went over the back lip of the harbor, filling a parking lot and low-lying streets and setting some cars afloat. In 2011 after the Japanese earthquake a series of surges cost $20 million of damage in the harbor.
American Samoa, Fiji alerts canceled
Residents of American Samoa were alerted of a tsunami warning by local broadcasters as well as church bells that rang territory-wide Saturday. An outdoor siren warning system was out of service. Those living along the shoreline quickly moved to higher ground.
As night fell, there were no reports of any damage, and the Hawaii-based tsunami center canceled the alert.
Authorities in the nearby island nations of Fiji and Samoa also issued warnings, telling people to avoid the shoreline because of strong currents and dangerous waves. In New Zealand, officials warned of possible storm surges.
Not the first eruption
The Hunga Tonga Hunga Ha'apai volcano is located about 64 kilometers (40 miles) north of the capital, Nuku'alofa. In late 2014 and early 2015, a series of eruptions in the area created a small new island and disrupted international air travel to the Pacific archipelago for several days.
The Matangi Tonga news site reported that scientists observed massive explosions, thunder and lightning near the volcano after it started erupting early Friday. Satellite images showed a 5-kilometer-wide (3-mile) plume rising into the air to about 20 kilometers (12 miles).
There is not a significant difference between volcanoes underwater and on land, and underwater volcanoes become bigger as they erupt, at some point usually breaching the surface, said Hans Schwaiger, a research geophysicist with the Alaska Volcano Observatory.
With underwater volcanoes, however, the water can add to the explosivity of the eruption as it hits the lava, Schwaiger added.