About Hunga Tonga–Hunga Haʻapai (HTHH) Volcano:
- It is a submarine stratovolcano in the Tongan archipelago in the southern Pacific Ocean.
- The HTHH volcano includes the small islands of Hunga Tonga and Hunga Ha’apai, along with shallow reefs along the caldera rim of a much larger submarine edifice in the western South Pacific Ocean, west of the main inhabited islands in the Kingdom of Tonga.
- The volcano is part of the highly active Tonga–Kermadec Islands volcanic arc, a subduction zone extending from New Zealand north-northeast to Fiji.
- The Tonga-Kermadec arc was formed as a result of the subduction of the Pacific Plate beneath the Indo-Australian Plate.
- It has erupted regularly over the past few decades.
What is a Stratovolcano?
- It is a tall, steep, and cone-shaped type of volcano.
- Unlike flat shield volcanoes, they have higher peaks.
- They are typically found above subduction zones, and they are often part of large volcanically active regions, such as the Ring of Fire that frames much of the Pacific Ocean.
- Strato Volcanoes comprise the largest percentage (~60%) of the Earth’s individual volcanoes, and most are characterized by eruptions of andesite and dacite, lavas that are cooler and more viscous than basalt.
- These more viscous lavas allow gas pressures to build up to high levels. Therefore, these volcanoes often suffer explosive eruptions.
- They are usually about half-half lava and pyroclastic material, and the layering of these products gives them their other common name, composite volcanoes.
- At their peak, they usually have a small crater. The crater may be filled with water or ice, or it may contain a volcanic dome during a period of relative inactivity.
