Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls, and being dark colored and denser.
Raoul Island is the largest and northernmost of the main Kermadec Islands, 900 km (560 mi) south south-west of 'Ata Island of Tonga and 1,100 km (680 mi) north north-east of New Zealand's North Island. It has been the source of vigorous volcanic activity during the past several thousand years that was dominated by dacitic explosive eruptions.
The Kermadec Islands are a subtropical island arc in the South Pacific Ocean 800–1,000 km (500–620 mi) northeast of New Zealand's North Island, and a similar distance southwest of Tonga. The islands are part of New Zealand. They are 33.6 km2 (13.0 sq mi) in total area and uninhabited, except for the permanently staffed Raoul Island Station, the northernmost outpost of New Zealand.
Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.
Protector Shoal is the shallowest point of the Protector Seamounts, a group of submarine volcanoes in the Southern Ocean. They are part of the South Sandwich island arc, a volcanic arc that has given rise to the South Sandwich Islands. Protector Shoal reaches a depth of 55 metres (180 ft) below sea level and is part of a larger group of seamounts that formed atop a larger ridge. Some of these seamounts bear traces of sector collapses, and one is capped by nested calderas.
Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges alone are estimated to account for 75% of the magma output on Earth. Although most submarine volcanoes are located in the depths of seas and oceans, some also exist in shallow water, and these can discharge material into the atmosphere during an eruption. The total number of submarine volcanoes is estimated to be over one million of which some 75,000 rise more than 1 kilometre above the seabed. Only 119 submarine volcanoes in Earth's oceans and seas are known to have erupted during the last 11,700 years.
A pumice raft is a floating raft of pumice created by some eruptions of submarine volcanoes or coastal subaerial volcanoes.
Several types of volcanic eruptions—during which material is expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.
James Healy Seamount is a submarine volcano located among the South Kermadec Ridge Seamounts south of New Zealand's Kermadec Islands. It consists of a volcanic cone that reaches a depth of 1,150 metres (3,770 ft) below sea level, two 2–2.5 kilometres (1.2–1.6 mi) and 1.3 kilometres (0.81 mi) wide calderas and a parasitic cone that reaches a depth of 950 metres (3,120 ft) below sea level. The flanks of the volcano are covered with pumice and volcanic rocks, and hydrothermal venting occurs inside the caldera.
Submarine eruptions are volcano eruptions which take place beneath the surface of water. These occur at constructive margins, subduction zones and within tectonic plates due to hotspots. This eruption style is far more prevalent than subaerial activity. For example, it is believed that 70 to 80% of the Earth's magma output takes place at mid-ocean ridges.
L'Esperance Rock, formerly known as French Rock and Brind Rock,(named after William Brind) is the southernmost islet in the Kermadec Islands, to the north of New Zealand. It is 80 km (50 mi) south of Curtis Island and 600 km (370 mi) northeast of East Cape on New Zealand's North Island. The smaller L'Havre Rock lies 8 km (5 mi) to the north-west of L'Esperance; it is a reef that barely reaches the surface. L'Esperance Rock is 250 m (820 ft) in diameter with an area of 4.8 ha. It rises to a height of 70 m (230 ft).
Hunga Tonga–Hunga Haʻapai is a submarine volcano in the South Pacific located about 30 km (19 mi) south of the submarine volcano of Fonuafoʻou and 65 km (40 mi) north of Tongatapu, Tonga's main island. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate. It lies about 100 km (62 mi) above an active seismic zone.
Monowai Seamount is a volcanic seamount to the north of New Zealand. It is formed by a large caldera and a volcanic cone just south-southeast from the caldera. The volcanic cone rises to depths of up to 100 metres (330 ft) but its depth varies with ongoing volcanic activity, including sector collapses and the growth of lava domes. The seamount and its volcanism were discovered after 1877, but only in 1980 was it named "Monowai" after a research ship of the same name.
Helen Clare Bostock, is an oceanographer researching past, present and future conditions in the Southern Ocean. In 2011 she led a research voyage on board the RV Tangaroa to the Solander Trough region of the Tasman Sea. Two years later she was deputy voyage leader for an expedition to the Mertz Polynya, Antarctica. In 2016 she was awarded the McKay Hammer, for her combined research achievements between 2013 and 2016.
Havre Seamount is an active volcanic seamount lying within the Kermadec Islands group of New Zealand, in the south-west Pacific Ocean, on the Tonga-Kermadec Ridge. Its most recent eruption took place in July 2012.
Volcano F is a submarine volcano in the Tonga Islands of the South Pacific Ocean. It is located 50 km (31 mi) northwest of Vavaʻu, between Late and Fonualei on the Tofua ridge. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate.
Macauley Island is a volcanic island in New Zealand's Kermadec Islands, approximately halfway between New Zealand's North Island and Tonga in the southwest Pacific Ocean. It is part of a larger submarine volcano that features a 10.5 by 7 kilometres wide underwater caldera northwest of Macauley Island. Two islets, Haszard Island and Newcome Rock, lie east offshore of Macauley Island. The island is mostly surrounded by high cliffs that make accessing it difficult; the inland parts are mostly gently sloping terrain covered with ferns and grasses.
Curtis Island is an island in the southwest Pacific. It is a volcanic island which, together with neighbouring Cheeseman Island, belongs to the Kermadec Islands, an outlying island group of New Zealand. It is a volcanic island with a fumarolically active crater, while vegetated slopes are nested by seabirds. There are uncertain reports of eruptions and the island has been uplifted by about 18 m (59 ft) during the past 200 years.
The South Kermadec Ridge Seamounts are a continuation of the volcanic island arc, formed at the convergent boundary where the Pacific Plate subducts under the Indo-Australian Plate. The subducting Pacific Plate created the Kermadec Trench, the second deepest submarine trench, to the east of the islands. The seamounts lie along the western aspect of the undersea Kermadec Ridge, which runs southwest from the Kermadec Islands towards the North Island of New Zealand and northeast towards Tonga.
East of the Vanuatu island of Epi can be found a series of active underwater volcanic cones and a caldera which last erupted in 2023. These series of submarine volcanoes are generally referred as East Epi, and the 3 bigger cones have specific names, from west to east, Epi-A, Epi-B and Epi-C. All of these cones have had intermittent activity in this and the last century.
