Ice tongue calving in Antarctica triggered by the Hunga Tonga volcanic tsunami, January 2022.

On 15 January 2022,the Hunga Tonga-Hunga Ha'apai volcano(20.54°S 175.39°W),a submarine volcano located about 65 km north of Tonga's main island in the South Pacific,violently erupted with a powerful explosion[1].The volcanic explosivity index(VEI)was estimated to be 6 indicating that the eruption was among the largest volcanic activity ever observed with modern geophysical instrumentation[2].The explosion ejected an enormous ash plume to record-breaking heights of～55 km[3]and caused atmospheric waves that propagated across the globe in less than 24 h[4].Although most tsunamis are triggered by underwater earthquakes rather than volcanic eruptions,this violent explosion caused a widespread tsunami that was observed all over the Pacific Ocean.The catastrophic tsunami resulted in three Tongan deaths and many others injured.Based on a preliminary model analysis,it took about 9-12 h for the rare volcano-triggered tsunami to reach Antarctica(US National Oceanic and Atmospheric Adminis-tration(NOAA)/Pacific Marine Environmental Laboratory(PMEL)/Center for Tsunami Research;).Limited tide gauge data from the Antarctic Penin-sula and Ross Sea show that the peak amplitude of the tsunami at the coast of Antarctica was on the order of～30 cm().