Gaua Island, formerly known as Santa Maria Island, is a small island of 20 km in diameter and belongs to the Banks Islands in northern Vanuatu. In the center of the island there is the caldera of 8 x 6 km wide caldera of the Gharat volcano. Within the caldera is the u-shaped Lake Letas, surrounding Mt. Gharat on all sides except southwest.
Vanuatu 1980, map of Banks Islands.
An erupting volcano on Ambrym Island is depicted below the map.
The stamp was issued in the series "1st Definitive Series — Maps of Vanuatu" and is existing inscribed in english "postage" on watermarked paper und in french "postes" on unwatermarked paper.
Vanuatu 1998, Lake Letas and Gharat Volcano.