A supervolcano is a volcano that has had an eruption with a volcanic explosivity index (VEI) of 8, the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers.
Mount Vesuvius is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about 9 km (5.6 mi) east of Naples and a short distance from the shore. It is one of several volcanoes forming the Campanian volcanic arc. Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera, resulting from the collapse of an earlier, much higher structure.
Mount Tarawera is a volcano on the North Island of New Zealand within the older but volcanically productive Ōkataina Caldera. Located 24 kilometres southeast of Rotorua, it consists of a series of rhyolitic lava domes that were fissured down the middle by an explosive basaltic eruption in 1886. While the 1886 eruption was basaltic, study has shown there was only a small basalt component to the previous recent rhyolitic predominant eruptions. This eruption was one of New Zealand's largest historical eruptions, and killed an estimated 120 people. The fissures run for about 17 kilometres (11 mi) northeast–southwest.
In volcanology, a Strombolian eruption is a type of volcanic eruption with relatively mild blasts, typically having a Volcanic Explosivity Index of 1 or 2. Strombolian eruptions consist of ejection of incandescent cinders, lapilli, and volcanic bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence. This type of eruption is named for the Italian volcano Stromboli.
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.
Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts. It is common for a large explosive eruption to have magmatic and phreatomagmatic components.
The Hatepe eruption, named for the Hatepe Plinian pumice tephra layer, sometimes referred to as the Taupō eruption or Horomatangi Reef Unit Y eruption, is dated to 232 CE ± 10 and was Taupō Volcano's most recent major eruption. It is thought to be New Zealand's largest eruption within the last 20,000 years. The eruption ejected some 45–105 km3 (11–25 cu mi) of bulk tephra, of which just over 30 km3 (7.2 cu mi) was ejected in approximately 6–7 minutes. This makes it one of the largest eruptions in the last 5,000 years, comparable to the Minoan eruption in the 2nd millennium BCE, the 946 eruption of Paektu Mountain, the 1257 eruption of Mount Samalas, and the 1815 eruption of Mount Tambora.
The 946 eruption of Paektu Mountain in Korea and China, also known as the Millennium Eruption or Tianchi eruption, was one of the most powerful volcanic eruptions in recorded history and is classified as a VEI-6 event. The eruption resulted in a brief period of significant climate change in Manchuria. The eruption occurred in late 946 CE.
A multi-component gas analyzer system (Multi-GAS) is an instrument package used to take real-time high-resolution measurements of volcanic gases. A Multi-GAS package includes an infrared spectrometer for CO2, two electrochemical sensors for SO2 and H2S, and pressure–temperature–humidity sensors, all in a weatherproof box. The system can be used for individual surveys or set up as permanent stations connected to radio transmitters for transmission of data from remote locations. The instrument package is portable, and its operation and data analysis are simple enough to be conducted by non-specialists.
Dispersal index is a parameter in volcanology. The dispersal index was defined by George P. L. Walker in 1973 as the surface area covered by an ash or tephra fall, where the thickness is equal or more than 1/100 of the thickness of the fall at the vent. An eruption with a low dispersal index leaves most of its products close to the vent, forming a cone; an eruption with a high dispersal index forms thinner sheet-like deposits which extends to larger distances from the vent. A dispersal index of 500 square kilometres (190 sq mi) or more of coarse pumice is one proposed definition of a Plinian eruption. Likewise, a dispersal index of 50,000 square kilometres (19,000 sq mi) has been proposed as a cutoff for an ultraplinian eruption. The definition of 1/100 of the near-vent thickness was partially dictated by the fact that most tephra deposits are not well preserved at larger distances.
There are two large sulfate spikes caused by mystery volcanic eruptions in the mid-1400s: the 1452/1453 mystery eruption and 1458 mystery eruption. Before 2012, the date of 1458 sulfate spike was incorrectly assigned to be 1452 because previous ice core work had poor time resolution. The exact location of this eruption is uncertain, but possible candidates include the submerged caldera of Kuwae in the Coral Sea, Mount Reclus and Tofua caldera. The eruption is believed to have been VEI-7.
A lava balloon is a gas-filled bubble of lava that floats on the sea surface. It can be up to several metres in size. When it emerges from the sea, it is usually hot and often steaming. After floating for some time it fills with water and sinks again.
Costanza Bonadonna is an Italian earth scientist who is a Full Professor of volcanology and geological risk at the University of Geneva. In 2020, she was named President-Elect of volcanology, geochemistry, and petrology at the American Geophysical Union (AGU).
The Haroharo Caldera is a 26 by 16 km postulated volcanic feature in Taupō Volcanic Zone of the North Island, New Zealand within the larger and older Ōkataina Caldera. Since 2010 further studies have tended to use the terms Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera to the features assigned to it. However the name is used in the peer reviewed literature to summarise and group these features based on gravitational and magnetic features.
Ōkataina Caldera is a volcanic caldera and its associated volcanoes located in Taupō Volcanic Zone of New Zealand's North Island. It has several actual or postulated sub calderas. The Ōkataina Caldera is just east of the smaller separate Rotorua Caldera and southwest of the much smaller Rotomā Embayment which is usually regarded as an associated volcano. It shows high rates of explosive rhyolitic volcanism although its last eruption was basaltic. The postulated Haroharo Caldera contained within it has sometimes been described in almost interchangeable terms with the Ōkataina Caldera or volcanic complex or centre and by other authors as a separate complex defined by gravitational and magnetic features.. Since 2010 other terms such as the Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera are often used, rather than a Haroharo Caldera classification.
The Cascade Volcanic Arc is a chain of volcanoes stretching from southern British Columbia down to northern California. Within the arc there is a variety of stratovolcanoes like Mount Rainier and broad shield volcanoes like Medicine Lake. But calderas are very rare in the Cascades, with very few forming over the 39 million year lifespan of the arc.
