Sao Jorge
Fissure vent in Portugal
Key Facts
Elevation
1,053 m (3,455 ft)
Type
Fissure vent
Location
38.650°, -28.080°
Region
Azores-Terceira Rift Volcanic Province
Rock Type
Basalt / Picro-Basalt
Tectonic Setting
Rift zone
Location
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Overview
The dominantly basaltic São Jorge Island is 55 km long and 6. 5 km wide. It was formed by fissure eruptions beginning in the eastern part of the island.
The western two-thirds of the island contains youthful, fissure-fed lava flows resembling those on neighboring Pico Island. Lava effused from three locations above the south-central coast during 1580, producing flows that reached the ocean. In 1808 a series of explosions took place from vents along the south-central crest of the island; one of the vents produced a lava flow that reached the southern coast.
Submarine eruptions have also been reported on several occasions from a submarine ridge to the SE. The 1964 event offshore W of Velas was considered "probable" by Madiera and Brum da Silveira (2003), who also provided 14C dates for several other Holocene eruptions.
Volcanic Hazards & Risk Assessment
Primary Hazards
Risk Level
Geological Composition & Structure
Rock Types
Tectonic Setting
Age & Formation
Eruption Statistics & Analysis
| Metric | Value | Global Ranking | Significance |
|---|---|---|---|
| Total Recorded Eruptions | Unknown | Low | Moderately active volcano |
| Maximum VEI | VEI Unknown | Minor | Local impact potential |
| Recent Activity | 124 years ago | Historical | Historically active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in Atlantic Ocean Volcanic Regions
Quick Info
- •Smithsonian ID: 382030
- •Evidence: Eruption Observed
- •Epoch: Holocene
About the Photo
The Pico da Velha cone is seen in this view of the interior of the island of São Jorge. The linear island is 54 km long and only about 6 km wide at its widest point. This cone is one of many along a volcanic ridge down the axis of the island. Eruptions recorded since 1580 have produced lava flows that reached the ocean, and submarine eruptions were reported from vents off the southern and southwestern coasts.
Photo by Luís A. da Silveira, 2007 (Wikimedia Commons).
Authority Sources
Related Volcanoes
Basic Information
This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.