It was an event that made me feel that even though the world is vast, the earth is still connected as one.
On the 15th (Saturday), a submarine volcano in the Tonga Islands in the South Pacific erupted. The erupting "Hunga Tonga Hunga Ha'apai volcano" has been erupting since the end of last year, and the volcanic plume this time seems to have reached an altitude of 19 kilometers.
As we have been told, the communication infrastructure in Tonga has been cut off, and we do not know the situation on the ground, and we do not know the full extent of the damage. I am very worried about what the situation is now.
Height of "volcanic tsunami" around the world
The eruption immediately issued a "tsunami warning" in Japan, and a 1.2-meter tsunami was observed in Kominato, Amami City, Kagoshima Prefecture. rice field. A fishing boat capsizes in Shikoku, and the news is being reported by the world's media.
How many tsunamis were observed in countries around the world? Let's summarize the information of foreign telephones and weather stations.
[Peru]
・Two bodies found on beach in northwestern Lambayeque department
・Many buildings along the coast are flooded
[California]
・1.3m tsunami observed at Port Saint Louis
・Two anglers were swept away by the tsunami at San Gregorio Beach, and one was taken to the hospital.
・In San Francisco, several surfers were rescued 200-300m offshore.
[Australia]
Tsunamis of 1.27m on Norfolk Island and 0.82m on the Gold Coast
[New Zealand]
・1.33m tsunami observed on Great Barrier Island
・Many boats sank in Tsutsukaka, boats detached from their moorings at the marina, causing serious damage such as collisions between boats.
[Hawaii]
・Observation of 0.82m tsunami on Kauai Island
・Coastal road flooded
・In Hawaii Island, the pier is flooded, and the canoes of the high school canoe club are swept away.
[Chile]
・A 1.74m tsunami was observed in Chanaral, 10,000km away from Tonga.
・Red warning issued for 6,400 km of coastline
[Alaska, USA]
・1m tsunami observed at King Cove
(↑ Peru)
Even in North America
Tsunamis are generally caused by earthquakes, and tsunamis caused by volcanoes like this one are said to be rare.
The worst tsunami caused by past volcanic eruptions was the Krakatau volcano in 1883. It is said that 36,000 people died in a huge tsunami.
The eruption of the Krakatau volcano was a historically large eruption that blew away most of the island, but there are points that make me think that this eruption may be even more spectacular. That is the "flying distance" of the explosion sound.
Explosions of the Krakatau volcano were reportedly heard from Rodrigues Island in the Indian Ocean about 5,000 kilometers away, but this time they were also heard from Alaska, 9,366 kilometers from Tonga, and Yukon in northern Canada. That's it.
A Yukon woman told CBC that the noise was so loud that it felt like a large truck passing by, and that it lasted for about an hour.
On the other hand, it seems that the explosion sound was not heard in Hawaii, which is closer to Tonga, so further investigation is awaited.
Changes in atmospheric pressure around the world
Professor Fumihiko Imamura of Tohoku University said in an NHK interview that the tsunami this time was caused by air vibrations (air shocks) caused by the eruption, causing the water level to rise. It is said that this is the result of changes in
Actually, it is said that there was a pressure change of about 2hPa in Japan, 2.5hPa in Switzerland, about 2hPa in the UK, and even more in New Zealand.
It's amazing how an eruption at one point physically "shocked" the world.
(↓Barometric pressure change in New Zealand)