Have a Merry Christmas and stay away from the hazardous Hunga volcano, the Tonga Geological Services advised the public today - warning that extreme hazards in the area up to five kilometres around the eruption, include possible explosions, surges, ballistic ejecta, tephra, lava domes, laze, vog, pumice shoals, volcanic edifice collapse and tsunamis.

The Tonga Geological Service has warned the public to stay out of the hazardous zones for at least 3-5 kilometres around the active Hunga volcano.

Taaniela Kula, the Deputy Secretary, Ministry of Lands & Natural Resources, released the volcanic hazard map for the Hunga Volcano on Christmas Eve.

• Zone 1 (RED) within 3km of the vent the public is advised to stay out of this zone due to the mixed magmatism in the system (and hence variable explosivity) occurring at other localities within the caldera.
• Zone 2 (Orange) within 5km of the vent the public is advised to use extreme caution.
• Zone 3 (Green) beyond 5km of the vent the public is advised of potential threat and be vigilant at all times.

He said the highest risk is in Zone 1 (3 km).

For 5km around the volcano there is “a moderate risk of vog, laze, pumice, submarine plumes, tephra, and tsunamis.”

The dispersal of the volcanic material and gases will be controlled by the prevailing winds.

TGS warned: “Observers should exercise caution downwind of the site.”

Vog is smog or haze containing volcanic dust and gases.

Laze, the combination of lava and haze, is a toxic mixture of hydrochloric acid formed by lava vaporizing seawater.

Ejecta are rock fragments and particles ejected by a volcanic eruption.

A pyroclastic surge is a fluidized mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. Pyroclastic surge include 3 types, which are base surge, ash-cloud surge, and ground surge.