Shock waves may have caused volcano tsunami

Paris: 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 on Monday.

GNS Tsunami Duty Officer Jonathan Hanson said it probably occurred in part thanks to a previous eruption of the same volcano one day earlier. "It is likely that the earlier 14 January eruption blew away part of the volcano above water, so water flowed into the extremely hot vent," wrote Hanson.

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.