About Sumisujima
Sumisujima is a caldera rising to 136 meters (446 feet) in Japan's Northwestern Pacific Volcanic Regions. It last erupted in 1916 CE, and volcanologists consider it an active volcanic system. The volcano has produced 20 recorded eruptions.
Geography & Climate
Sumisujima is located in Japan, within the Izu Volcanic Arc of the broader Northwestern Pacific Volcanic Regions. Situated at 31.44° N, 140.05° E in the Northern Hemisphere, the volcano lies within a subtropical climate zone. At just 136 meters above sea level, Sumisujima is a relatively low-elevation volcanic feature. Despite its modest height, it remains an active geological formation with the same underlying magmatic processes as its taller counterparts. The volcanic landform is characterized as a caldera, which describes the physical shape and structure of the volcanic edifice as observed from the surface.
Geological Context
Sumisujima 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 Japan near Sumisujima, 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 dacite, an intermediate to silica-rich volcanic rock. This composition typically produces more viscous magma, leading to more explosive eruptions with ash columns and pyroclastic flows. Andesitic and dacitic magmas build pressure before erupting, which is why volcanoes with this rock chemistry are often associated with Plinian-style eruptions that can send ash tens of kilometers into the atmosphere and disrupt aviation across entire regions.
Eruption History Summary
Sumisujima has 20 recorded eruptions in the geological database, spanning from 1975 CE to 2024 CE. With an average interval of roughly 2 years between eruptions over a span of 49 years, this is one of the more frequently active volcanoes in the database. This persistent activity suggests a robust and well-supplied magma system beneath the volcano. With eruptive activity as recently as 2024 CE, Sumisujima remains an actively monitored volcano.
Significance
Its 20 recorded eruptions make it one of the most prolific volcanoes in our database, reflecting a persistent and well-documented eruptive history that has provided volcanologists with extensive data for understanding eruption patterns and forecasting future activity. Given its recent activity, Sumisujima is closely monitored by geological survey organizations to provide early warning of future unrest.
GVP Reference Summary
Sumisujima (also known as Smith Rocks) is a steep-sided basaltic pinnacle that forms part of the outer southern flank of a 8-9 km submarine caldera that truncates a 20-km-wide seamount. The caldera was formed between about 60,000 and 30,000 years ago. The Shirane dacitic central cone, 3 km wide and 800 m high, rises to within 8 m of the ocean surface in the eastern side of the caldera, whose 600-700 m walls and outer flanks expose basaltic, andesitic, and rhyolitic rocks. Two large submarine cones, Sumisu Knolls No. 1 and 2, lie west of the caldera. Submarine eruptions have been reported from a number of locations near Sumisujima, the last of which occurred in 1916. Water discoloration has frequently been observed since the 1970's. In October 1992 a 6-km-long zone of discolored water was seen extending from the shallow Shirane rock mass near the eastern rim of the caldera, which rises to within 7 m of the ocean surface and is the youngest feature of the volcanic complex.
— Smithsonian Institution, Global Volcanism Program
20 Recorded Eruptions
| Year | VEI | Type | Area |
|---|---|---|---|
| 2024 | — | Uncertain Eruption | — |
| 2005 | 0 | Uncertain Eruption | — |
| 2003 | 0 | Uncertain Eruption | — |
| 2002 | 0 | Uncertain Eruption | — |
| 2001 | 0 | Uncertain Eruption | — |
| 2000 | 0 | Uncertain Eruption | — |
| 1998 | 0 | Uncertain Eruption | — |
| 1997 | 0 | Uncertain Eruption | — |
| 1996 | 0 | Uncertain Eruption | — |
| 1995 | 0 | Uncertain Eruption | — |
| 1994 | 0 | Uncertain Eruption | — |
| 1994 | 0 | Uncertain Eruption | — |
| 1993 | 0 | Uncertain Eruption | — |
| 1992 | 0 | Uncertain Eruption | Shirane (7.5 km NE of Smith Rocks) |
| 1991 | 0 | Uncertain Eruption | — |
| 1989 | 0 | Uncertain Eruption | — |
| 1989 | 0 | Uncertain Eruption | — |
| 1977 | 0 | Uncertain Eruption | — |
| 1976 | 0 | Uncertain Eruption | — |
| 1975 | 0 | Uncertain Eruption | — |
Real-Time Data
USGS Alert Level
Thermal Anomalies
Frequently Asked Questions About Sumisujima
Is Sumisujima an active volcano?+
Yes, Sumisujima is considered an active volcano. Its most recent eruption was in 1916 CE. The volcano is monitored by geological agencies, and its activity status is based on observed eruptions within recorded history.
When did Sumisujima last erupt?+
The most recent recorded eruption of Sumisujima occurred in 2024 CE. The eruption was classified as a "Uncertain Eruption." Sumisujima has 20 recorded eruptions in total.
How high is Sumisujima?+
Sumisujima has a summit elevation of 136 meters (446 feet) above sea level. At 136 meters, it is a relatively low-elevation volcano.
What type of volcano is Sumisujima?+
Sumisujima is classified as a Caldera. Calderas are large volcanic depressions formed when a volcano erupts so powerfully that its magma chamber collapses, creating a basin that can be kilometers wide. They are often sites of some of Earth's largest eruptions.
Where is Sumisujima located?+
Sumisujima is located in Japan, in the Northwestern Pacific Volcanic Regions. More specifically, it lies within the Izu Volcanic Arc. Its exact coordinates are 31.440° latitude, 140.051° longitude.
Is it safe to visit Sumisujima?+
Visiting Sumisujima requires checking current volcanic activity and alert levels. As an active volcano with eruptions as recent as 1916 CE, conditions can change rapidly. Always consult local geological authorities and follow official warnings before visiting. Many active volcanoes have designated safe viewing areas and guided tour options.
