About Supply Reef
Supply Reef is a stratovolcano rising to -8 meters (-26 feet) in United States's Northwestern Pacific Volcanic Regions. No historical eruptions have been recorded, though the volcano is classified based on geological evidence of past activity.
Geography & Climate
Supply Reef is located in United States, within the Mariana Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 20.13° N, 145.10° E in the Northern Hemisphere, the volcano lies within a tropical climate zone. With an elevation of -8 meters — below sea level — Supply Reef 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
Supply Reef 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 United States near Supply Reef, 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
Supply Reef is a conical submarine volcano in the northern Mariana Islands that rises to within 8 m of the surface. The andesitic seamount lies about 17 km NW of the Maug Islands, the emergent summit of a submarine volcano that is joined to Supply Reef by a low saddle at a depth of about 1,800 m. Supply Reef was mapped as Quaternary; living corals on the crater rim suggest that it is either dormant or extinct (Corwin, 1971). Submarine eruptions previously attributed to this volcano based primarily on acoustic data have been reassigned to Ahyi Seamount, which was unknown at the time of those reports.
— Smithsonian Institution, Global Volcanism Program
0 Recorded Eruptions
No eruption records available for Supply Reef.
Real-Time Data
USGS Alert Level
Thermal Anomalies
Frequently Asked Questions About Supply Reef
Is Supply Reef an active volcano?+
Supply Reef is not currently classified as active. Its activity evidence is listed as "Evidence Uncertain." No recorded eruptions have been documented. However, no volcano is ever considered permanently extinct.
How high is Supply Reef?+
Supply Reef has a summit elevation of -8 meters (-26 feet) above sea level. With an elevation of -8 meters (below sea level), this is a submarine or submerged volcanic feature.
What type of volcano is Supply Reef?+
Supply Reef 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 Supply Reef located?+
Supply Reef is located in United States, in the Northwestern Pacific Volcanic Regions. More specifically, it lies within the Mariana Volcanic Arc. Its exact coordinates are 20.130° latitude, 145.100° longitude.
Is it safe to visit Supply Reef?+
Supply Reef can generally be visited, but as with any volcano, visitors should check local conditions and any advisory notices before traveling. United States may have specific regulations for accessing volcanic areas. Guided tours are often the safest and most informative way to experience a volcano.
