About Unnamed
Unnamed is a stratovolcano rising to -65 meters (-213 feet) in Tonga's Tonga-Kermadec Volcanic Regions. No historical eruptions have been recorded, though the volcano is classified based on geological evidence of past activity.
Geography & Climate
Unnamed is located in Tonga, within the Tofua Volcanic Arc of the broader Tonga-Kermadec Volcanic Regions. Situated at 21.15° S, 175.75° W in the Southern Hemisphere, the volcano lies within a tropical climate zone. With an elevation of -65 meters — below sea level — Unnamed is a submarine or submerged volcanic feature. Submarine volcanoes make up the majority of Earth's volcanic activity, though most eruptions go unobserved beneath the ocean surface. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.
Geological Context
Unnamed sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in Tonga near Unnamed, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is andesite / basaltic andesite, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.
GVP Reference Summary
A large submarine volcano rises to within 65 m of the ocean surface west of Tongatapu Island. The volcano was informally named Volcano 1 by scientists on the bathymetric survey that mapped it in 2003. The summit of the andesitic-to-dacitic seamount is cut by a large 4.5 x 7 km caldera, with two young scoria cones forming the high point. A chain of explosion craters up to 100 m deep cut the flank of one of the scoria cones, and thick deposits of ash and scoria cover the caldera floor nearby. The lack of organic sediments between volcaniclastic deposits exposed in one portion of the caldera wall suggest it was constructed within the past 200 years. Diffuse low-temperature hydrothermal vents and vigorous gas discharge occurs near the explosion craters.
— Smithsonian Institution, Global Volcanism Program
0 Recorded Eruptions
No eruption records available for Unnamed.
Real-Time Data
USGS Alert Level
Thermal Anomalies
Frequently Asked Questions About Unnamed
Is Unnamed an active volcano?+
Unnamed is classified as active based on credible evidence of past eruptions. Although its last known eruption was in prehistoric times, volcanologists consider it capable of erupting again.
How high is Unnamed?+
Unnamed has a summit elevation of -65 meters (-213 feet) above sea level. With an elevation of -65 meters (below sea level), this is a submarine or submerged volcanic feature.
What type of volcano is Unnamed?+
Unnamed is classified as a Stratovolcano. Stratovolcanoes (also called composite volcanoes) are steep, conical volcanoes built up by many layers of hardened lava, tephra, and volcanic ash. They are among the most common and dangerous types, known for explosive eruptions.
Where is Unnamed located?+
Unnamed is located in Tonga, in the Tonga-Kermadec Volcanic Regions. More specifically, it lies within the Tofua Volcanic Arc. Its exact coordinates are -21.150° latitude, -175.750° longitude.
Is it safe to visit Unnamed?+
Unnamed can generally be visited, but as with any volcano, visitors should check local conditions and any advisory notices before traveling. Tonga may have specific regulations for accessing volcanic areas. Guided tours are often the safest and most informative way to experience a volcano.
