The Tonga eruption explained, from tsunami warnings to sonic booms

Just a few weeks ago, a submarine volcano identifiable by two small uninhabitable islands in the Kingdom of Tonga began to erupt. Its outburst initially seemed innocuous, with ashen plumes and moderate explosions that few people living outside the archipelago noticed.

But in the past 24 hours, that volcano, named Hunga Tonga-Hunga Ha'apai, forced the world to sit up and pay attention.

After a moment of calm earlier this month, its eruptive activity turned increasingly violent. The middle section of the island vanished on satellite imagery. Towering columns of ash began to produce record-breaking amounts of lightning.

Jackie Caplan-Auerbach, a seismologist and volcanologist at Western Washington University in Bellingham, says the blast involved a “mind-boggling amount of energy.” But there isn’t enough data right now to ascertain the precise cause of the tsunami.