An underwater volcano erupted off Tonga, triggering a tsunami warning for several South Pacific island nations on Saturday.
An underwater volcano erupted near the remote Pacific nation of Tonga on Saturday, triggering a tsunami warning for the South Pacific and the west coast of the United States, and causing strong waves and currents in many coastal areas.
The volcano erupted dramatically, sending gas and ash plumes thousands of feet into the atmosphere, although initial reports of damage were limited.
A four-foot tsunami wave was reported in Tonga's capital, Nuku'alofa, sending people to higher ground, and eyewitnesses said ash fell from the sky. According to The Associated Press, there was no immediate official report on the extent of the injuries or damage, but internet service in the country was disrupted, making it difficult to assess.
Despite Tonga's geographical isolation, after the initial eruption a loud sound was heard as far away as New Zealand, 1,100 miles northeast of Tongatapu, the main island of the archipelago.
In the United States, officials urged residents of most coastal areas along the West Coast, Alaska and Hawaii to stay off the coast and move to higher ground.
In Japan, the country's meteorological agency reported that the four-foot wave had reached the far southern island of Amami Oshima, and smaller surges occurred in other areas along Japan's Pacific coast, according to Reuters.
Warnings were heard across the Pacific. New Zealand's National Emergency Management Agency advised people in coastal areas to expect "rapid and unusual currents and unexpected surges along the coast". And on their Facebook pages, meteorological services for Fiji and Samoa also issued alerts, advising people to stay away from low-lying coastal areas.
The volcano, Hunga Tonga-Hunga Hapai, which is about 40 miles north of Tongatapu, was relatively dormant for many years. According to a report by the Smithsonian Institution's Global Volcanism Program, it began to erupt intermittently in December, but by January 3, activity had decreased significantly.
Satellite imagery of the eruption shared on Twitter by New Zealand's National Institute of Water and Atmospheric Research on Saturday showed "a brief spike in air pressure in New Zealand as an atmospheric shock wave."
A port official removes debris from rising waters in Santa Cruz, Calif., on Saturday. credit ... Nick Corey / The Associated Press
According to Brian Garcia, a Warning Coordinating Meteorologist, the tsunami came into motion when an underwater volcano erupted in the South Pacific on Saturday in parts of California's central coast including ports, marinas, low-lying roads, roads and parking lots. I got filled with water. National Weather Service in the San Francisco Bay Area.
The water also crashed on the walls of the sea, he said. But the damage appeared to be limited to the lowest areas of the coastline.
In the United States, the National Tsunami Warning Center issued a tsunami advisory for the West Coast for Pacific time Saturday morning, which includes the Washington and Oregon coasts, warning that strong currents and waves will cause "or very near" people in the water. would pose a threat to. , "The first wave may not be the biggest," said the advisor.
By 8:30 a.m., water levels in Monterey, California and San Francisco had risen to six feet, and higher levels were expected later in the day. In Port San Luis Harbour, between San Jose and Los Angeles, waves greater than four feet were measured by the National Oceanic and Atmospheric Administration.
Water rose in Santa Cruz Harbor, damaging some boats and submerging the parking lot, and people were evacuated from docks, sidewalks and nearby shops. "We have literally seen cars floating by," said Mr. Garcia.
On a beach near Pillar Point Harbor, 25 miles south of San Francisco, two people who were standing on a dock were washed away at sea, but were quickly rescued and no one was injured, a local fire department official said. Not done.
A tsunami wave may not appear as a single large wave, but instead involves a rapid and continuous flow of water in low-lying areas over tens of minutes.
“It becomes very dangerous because there is a lot of water here and it is moving so fast; You can't outrun it, and you can't overtake it," Mr. Garcia said.
The National Weather Service has advised anyone in the coastal areas of California, Oregon, Washington, British Columbia and Alaska to "get in and out of the beach, as the tsunami is expected to affect the coast and gulf for the remainder of the day." . harbour and marina."
The US National Weather Service issued a tsunami advisory for the entire west coast following a massive volcanic eruption in Tonga.
Tsunamis form when large amounts of water – in the ocean, in a bay or a lake – are displaced quickly, usually through earthquakes or volcanic activity.
A four-foot tsunami struck the South Pacific nation of Tonga on Saturday when a nearby underwater volcano about 40 miles north of the archipelago's main island erupted spectacularly, sending ash into the sky, and became visible from space. The giver was making an explosive plume. ,
The tsunami that killed hundreds of people in Indonesia in December 2018 in Sumatra and Java was also caused by volcanic activity. About half an hour ago there was an eruption on the volcanic island of Anak Krakatau.
In an earthquake, water displacement can occur when the ground shakes as a fault breaks. This was the mechanism by which a magnitude 9.1 earthquake in the Aceh province of northern Indonesia on December 26, 2004, caused large waves in the Indian Ocean and killed 225,000 people.
Several other tsunamis have also followed earthquakes, including in September 2018, which devastated the city of Palu on the Indonesian island of Sulawesi after a magnitude 7.5 earthquake.
Volcanic activity creates tsunamis differently. One possibility is an explosive eruption, or the general weakening of the sides of a volcano passing hot magma. Either way, part of the volcano could collapse, causing landslides that could displace water.
Another possible mechanism is the collapse of a magma chamber beneath the volcano as it empties during an eruption.
Volcano-related tsunamis are not uncommon. An eruption in Japan in 1792 produced waves several hundred feet high. A landslide during the 1980 eruption of Mount St. Helens in Washington created large waves in a nearby lake.
Perhaps the most famous volcanic disaster in history, the 1883 eruption of Krakatau, also known as Krakatau, triggered a tsunami that killed thousands. (Anak Krakatau Island was formed on the site of Krakatau, which was wiped out in the 1883 incident.)
Hunga Tonga The Hunga Haapai volcano erupted on Saturday, causing huge tsunami waves in the Pacific Ocean. Credits ... Planet Labs PBC/Planet Labs PBC, via The Associated Press
The volcano that erupted on Saturday and triggered a tsunami in the Pacific Ocean was relatively dormant for many years.
Hunga Tonga-Hunga Haapai Volcano is partially submerged about 40 miles north of Tongatapu, the main island of the nation of Tonga. According to a report by the Smithsonian Institution's Global Volcanism Program, it began to erupt intermittently in December, but by January 3, activity had decreased significantly.
According to the BBC, the volcano erupted in 2014, creating a new island that eventually became home to blooming flora and barn owls.
Satellite imagery of the eruption shared on Twitter by New Zealand's National Institute of Water and Atmospheric Research on Saturday showed "a brief spike in air pressure in New Zealand as an atmospheric shock wave."
In a thread on Twitter, Dr. Janine Krippner, a volcanologist at the Smithsonian Institution, said that "the majority of the volcano is submarine."
The strength and potential impact of an eruption is estimated using the Volcanic Explosivity Index, or VEI, which takes into account the amount of material ejected during the eruption and the height the plume reaches.
VEI Saturday's eruption has not yet been predicted, but prior to the eruption, the volcano had a maximum VEI. It was supposed to be able to explode with 2 of
VEI Explosions with magnitude 6 or more send so much gas and particles into the atmosphere that they can have a cooling effect on the climate for many years, by reflecting more sunlight away from the Earth's surface. But explosions of that magnitude are very rare. The latest was Mount Pinatubo in the Philippines in 1991.
The city of Meulaboh, Indonesia, was the hardest-hit area by a 9.0 earthquake and tsunami in 2004. credit ... AFP / Getty Images
According to data from the National Oceanic and Atmospheric Administration, there have been 296 tsunami events since 2001.
But devastating tsunamis are rare events. According to the Global Historical Tsunami Database, tsunamis that cause damage or death near their source occur only twice per year. Tsunamis that cause damage or death along coasts more than 620 miles away occur about twice per decade.
Indian Ocean in 2004
On December 26, 2004, after a 9.1 magnitude underwater earthquake struck off the Indonesian island of Sumatra, water walls traveled thousands of miles across the Pacific, including more than 250,000 in half a dozen countries in South and Southeast Asia. People were killed, thousands of people were killed. missing more.
The earthquake set off a tsunami that produced speeds of up to 500 mph, then crashed into coastal areas of Sri Lanka, India, Thailand, Indonesia, the Maldives and Malaysia as 40-foot-high walls of water.
In 2011, a burning tsunami in Natori, Japan, swallowed homes. Credits ... Kyodo News, 2011 via Associated Press Japan
An 8.9-magnitude earthquake off the east coast of Honshu, Japan, triggered a devastating tsunami on March 11, 2011, sending huge waves to coastal cities in northern Japan.
According to the National Oceanic and Atmospheric Administration, the tsunami was "seen throughout the Pacific and caused tremendous local devastation." The tsunami also triggered tidal surges in parts of South America.
The highest tsunami wave was 127 feet in Iwate Prefecture, an area 300 miles north of Tokyo.
Indonesia in 2018
Within months of each other, two tsunamis caused major destruction in parts of Indonesia.
On September 28, 2018, a tsunami triggered by a 7.5 magnitude earthquake struck the island of Sulawesi in Indonesia, destroying thousands of homes and killing more than 1,200 people.
The damage was particularly devastating because Indonesia's early warning system for tsunamis had not turned off. The open water tsunami buoy had not operated since 2012 due to vandalism and lack of maintenance.
Three months later, on December 22, an underwater landslide caused by volcanic activity triggered a second tsunami that affected areas around the Sunda Strait, including the Pandeglang district, Serang and the beaches of South Lampung, according to NOAA.
In 1960, a 9.5-magnitude earthquake off the coast of Chile killed 1,600 people and damaged the city of Valdivia.
In 1960, a 9.5-magnitude earthquake, considered the largest of the 20th century, struck off the coast of Chile outside the city of Valdivia, causing a tsunami. About 1,600 people died in this disaster, of which tsunamis were responsible for 1,000 deaths. According to NOAA, that tsunami killed 60 people on the Hawaiian Islands and 200 in Japan.
Japan 1792
One of the most devastating tsunamis occurred in Japan at the end of the 18th century. The descriptions of the disaster in Japanese literature are somewhat conflicting, especially with regard to dates, but it has been estimated that in the winters of 1791 and 1792, there was a strong eruption of Mount Unzen volcano on the island of Kyushu, which moved south-west. The western most point. In Japan, that lasted for months.
At the end of the eruption, the side of the mountain collapsed and caused a tsunami, which was thrown east towards the city of Kumamoto. The disaster has been recorded as having killed 15,000 people, and a third of them were killed by the wave.
