A rare volcano-triggered tsunami sparked by the eruption of Hunga Tonga-Hunga Ha’apai in Tonga could have been caused by shock waves or shifting underwater land, experts said Monday
Paris, (APP – UrduPoint / Pakistan Point News – 17th Jan, 2022 ) :A rare volcano-triggered tsunami sparked by the eruption of Hunga Tonga-Hunga Ha’apai in Tonga could have been caused by shock waves or shifting underwater land, experts said Monday.
“This meant that the Saturday evening eruption initially occurred underwater and exploded through the ocean, causing a widespread tsunami,” he said.
Two days after Hunga Tonga-Hunga Ha’apai’s massive explosion, the nation’s 100,000 population remained virtually cut off from the rest of the world with crippled communications and stalled emergency relief efforts.
In a volcanic eruption, magma rising to the surface of the Earth’s crust causes volcanic gases to be released that then push their way out from underground, creating pressure.
“But more likely largely by a landslide on the submarine part of the volcanic edifice triggered by the explosive eruption.” Yet another possibility is that the volcano’s special location just beneath the surface of the ocean could have made its effects worse.
The volcano’s 1,800 metres of height is almost entirely submerged beneath the surface of the ocean, the edge of its crater forming an uninhabited island.
“When eruptions happen deep in the ocean, the water tends to muffle the activity. When it happens in the air, the risks are concentrated to the immediate area,” Paris-based geologist Raphael Grandin told AFP.
“But when it’s just under the surface, that’s when the tsunami risk is greatest,” he said.
– Exceptionally loud eruption – People are reported to have heard Hunga Tonga-Hunga Ha’apai’s eruption as far away as Alaska, 9,000 kilometres from the source, which Grandin said is “exceptional”.
“As far as I know the last explosion that was audible at that distance was caused by the Krakatoa volcano in Indonesia in 1883 — it killed 36,000 people,” he said.
Experts also said that while the volcano could experience further activity, past research shows an eruption of Saturday’s scale probably only occurs every 1,000 years.
Scientists who commented on the phenomenon said they would know more about how it took place once communication with the Pacific nation of some 170 islands could be restored.