1:45 PM - 2:05 PM
[MGI25-01] The Love Affair of a Volcanic Geologist: Five Decades of Working with the Volcanoes of the Kingdom of Tonga
★Invited Papers
Keywords:Tonga, Volcanoes, Volcanic hazards
The fascination for the volcanoes of the Kingdom of Tonga, SW Pacific first came about in July 1974 when I visited Tonga on a SW Pacific cruise. From that time on ‘Tonga and its volcanoes became a part of my life.
The Tofua Volcanic Arc (TVA) and the Lau Basin form a prominent tectonic feature in the SW Pacific and is a classic example of an active oceanic island arc back-arc. The arc itself comprises a series of several dozen active, dormant, and extinct, subaerial, and submarine volcanic centres that have formed on a N-S trending submarine ridge, between latitudes 14.5oS and 26oS. ln the northern and central parts, the arc is located 40-50 km W of the Tonga Platform. Active volcanism has been occurring along the entire length of the TVA since its initiation after the formation of the Lau Basin between 3 Ma and 5 Ma. During recent decades eruptions have occurred at five centres, with several eruptions resulting in the formation of ephemeral islands. The recent eruption of Hunga Tonga Hunga Ha’apai and the resultant tsunami has attracted considerable interest in the international scientific community. Hazards that have manifested the TVA volcanoes include lava flows, pyroclastic fall and flows, pumice rafts, ephemeral islands, and edifice collapse.
In the north-central part of the Lau Basin, the island of Niuafo’ou provides a unique example of a subaerial shield volcano in an active back-arc basin. Since the early 1800s it has been the most active of the Tonga volcanoes with possible ten eruptions occurring, the most recent being in September 1946, after which the island was evacuated until 1958. Three eruptions have destroyed villages and large tracks of arable lands. Niuafo’ou has a semi-permanent population of about 600-700 Tongans who are willing to accept the substantial risk of living on and active volcano. Hazards that have manifested Niuafo’ou include lava flows, pyroclastic fall and flows, volcanic gases, and acid rain and recently a small pumice raft.
This paper will provide details of some of my experiences with the volcanoes of Tonga.
The Tofua Volcanic Arc (TVA) and the Lau Basin form a prominent tectonic feature in the SW Pacific and is a classic example of an active oceanic island arc back-arc. The arc itself comprises a series of several dozen active, dormant, and extinct, subaerial, and submarine volcanic centres that have formed on a N-S trending submarine ridge, between latitudes 14.5oS and 26oS. ln the northern and central parts, the arc is located 40-50 km W of the Tonga Platform. Active volcanism has been occurring along the entire length of the TVA since its initiation after the formation of the Lau Basin between 3 Ma and 5 Ma. During recent decades eruptions have occurred at five centres, with several eruptions resulting in the formation of ephemeral islands. The recent eruption of Hunga Tonga Hunga Ha’apai and the resultant tsunami has attracted considerable interest in the international scientific community. Hazards that have manifested the TVA volcanoes include lava flows, pyroclastic fall and flows, pumice rafts, ephemeral islands, and edifice collapse.
In the north-central part of the Lau Basin, the island of Niuafo’ou provides a unique example of a subaerial shield volcano in an active back-arc basin. Since the early 1800s it has been the most active of the Tonga volcanoes with possible ten eruptions occurring, the most recent being in September 1946, after which the island was evacuated until 1958. Three eruptions have destroyed villages and large tracks of arable lands. Niuafo’ou has a semi-permanent population of about 600-700 Tongans who are willing to accept the substantial risk of living on and active volcano. Hazards that have manifested Niuafo’ou include lava flows, pyroclastic fall and flows, volcanic gases, and acid rain and recently a small pumice raft.
This paper will provide details of some of my experiences with the volcanoes of Tonga.