Graciosa
Stratovolcano in Portugal
Key Facts
Elevation
402 m (1,319 ft)
Type
Stratovolcano
Location
39.020°, -27.970°
Region
Azores-Terceira Rift Volcanic Province
Rock Type
Basalt / Picro-Basalt
Tectonic Setting
Rift zone
Location
Loading map...
Overview
The SE end of Graciosa, the northernmost of the central Azorean islands, contains a 0. 9 x 1. 6 km caldera with active fumaroles.
The SE caldera rim is the high point of the 7 x 12 km island. The caldera has been the source of eruptions producing significant tephra falls, pyroclastic flows, lahars, and lava flows. Fumaroles are present in a volcanic cave inside the caldera, and a submarine fumarole occurs off the NW coast.
Scoria cones erupted along several widely spaced NE-SW-trending fissures fed a youthful lava field that forms the NW end of the island. The most recent eruption from Pico Tomao, NW of the caldera, produced a lava flow during the mid-to-late Holocene that reached the eastern coast NW of the village of Praia.
Volcanic Hazards & Risk Assessment
Primary Hazards
- Pyroclastic flows
- Lava flows
- Volcanic bombs and ballistics
- Lahars and mudflows
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 | 3976 years ago | Historical | Historically active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in Atlantic Ocean Volcanic Regions
Quick Info
- •Smithsonian ID: 382040
- •Evidence: Eruption Dated
- •Epoch: Holocene
About the Photo
The south of Graciosa island is seen in this aerial view from the southwest. The village of Luz is at the center of the image. On the right (the southeast end of the island), is the 0.9 x 1.5 km Vulcão Central caldera, which formed between 60,000 and 11,000 years ago; the caldera rim forms the highest point of the 7 x 12 km island. The lava cave Furna Do Enzofre is situated in the southeastern part of the caldera, and exhibits fumarolic activity. Vegetated volcanic cones and part of the approximately 700,000 year old Serra das Fontes complex can be seen in the left of the photo.
Photo by Angrense, 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.