The 50-year-old British national had lived in the small Pacific nation with her husband, James, since they got married.
The New Zealand High Commission is reporting significant damage along the western coast of the main island of Tongatapu, where there are many holiday resorts, as well as the capital, Nuku'alofa, in the north.
While initial reports suggest there are no mass casualties, the situation in other parts of the archipelago remain unknown.
The United Nations says it’s concerned by a distress signal coming from the isolated, low-lying islands of Fonoi and Mango, which are home to around 100 people.
Geologist Dr Chris Firth says the risk of further volcanic activity remains.