Don Joao de Castro Bank
Shield in Portugal
Key Facts
Elevation
-13 m (-43 ft)
Type
Shield
Location
38.230°, -26.630°
Region
Azores-Terceira Rift Volcanic Province
Rock Type
Basalt / Picro-Basalt
Tectonic Setting
Rift zone
Location
Loading map...
Overview
Don Joao de Castro Bank is a large submarine volcano that rises to within 13 m of the ocean surface roughly halfway between Terceira and San Miguel Islands. Pillow lavas form the base of the volcano, which is capped by basaltic hyaloclastites. A submarine eruption during December 1720 produced an ephemeral island that attained a length of 1.
5 km and a height of about 250 m before it was eroded beneath the surface two years later. The volcano (also spelled Dom Joao de Castro) was named after the Portuguese hydrographic survey vessel that surveyed the bank in 1941. Two youthful craters, one tephra covered and the other sediment free, are located on the NW flank.
The submarine volcano has a shallow fumarole field and remains seismically active.
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 | 306 years ago | Historical | Historically active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in Atlantic Ocean Volcanic Regions
Quick Info
- •Smithsonian ID: 382070
- •Evidence: Eruption Observed
- •Epoch: Holocene
About the Photo
This side-viewing sonar image shows two 45 x 90 m craters on the NW flank of Don Joao de Castro Bank in the Azores taken by U.S. Navy submarine NR-1. The younger left crater displays a floor consisting of a chilled lava lake with polygonal surface fractures. The right crater is much less distinct because its surface is obscured by tephra deposits. The line at the right is the center track line of the sonar image.
U. S. Navy image courtesy of Rick Wunderman, 2003 (Smithsonian Institution).
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.