Santiago

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 0.22°S
  • 90.77°W

  • 920 m
    3018 ft

  • 353090
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Santiago.

The Global Volcanism Program has no Weekly Reports available for Santiago.

The Global Volcanism Program has no Bulletin Reports available for Santiago.

The elongated shield volcano of Santiago Island, also known as San Salvador Island or James Island, is dotted with Holocene pyroclastic cones. Fresh-looking lava flows from these cones blanket the flanks of the volcano. The 920-m-high summit ridge, lined with a chain of NW-trending cinder and spatter cones, is located at the NW end of the island. Prominent flank tuff cones occur at the western and eastern coasts of Santiago. The most recent activity at Santiago has been concentrated at the NW and SE ends of the island. The spectacular pahoehoe lava flows at James and Sullivan Bays, on opposite ends of the island, were erupted during historical time. The James Bay flows were dated by fragments of marmalade pots left by buccaneers in 1684 that were subsequently embedded in the lava flows described by Charles Darwin in 1835.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1904 1906 Dec 15 ± 45 days Confirmed 0 Historical Observations SE flank
1897 Unknown Confirmed 0 Historical Observations SE flank (Sullivan Bay?)
1759 ± 75 years Unknown Confirmed   Anthropology West flank (James Bay)

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.


Synonyms

San Salvador | James | Olmedo | Gil | York

Cones

Feature Name Feature Type Elevation Latitude Longitude
Albany Island Cone 0° 10' 0" S 90° 51' 0" W
Cabo Cowan Tuff cone 284 m 0° 11' 0" S 90° 50' 0" W
Inn, Cerro Cone 0° 17' 0" S 90° 34' 0" W

Craters

Feature Name Feature Type Elevation Latitude Longitude
Bartholomew Island Crater 109 m 0° 17' 0" S 90° 33' 0" W
Salt Lake Crater 0° 14' 0" S 90° 50' 0" W
A spectacular suite of volcanic features flanks Sullivan Bay, at the eastern end of Santiago Island. This view looks NE across the bay to Bartolomé Island. The sharp pinnacle at the left, a remnant of an eroded tuff cone, is one of the many scenic highlights of the Galápagos Islands. Bartolomé Island contains eroded tuff cones, a dissected solidified lava lake, and a youthful lava plateau. The flat coastline of Santiago Island in the foreground is formed from a vast field of youthful pahoehoe lava flows that wraps around the SE corner of the island.

Photo by Lee Siebert, 1978 (Smithsonian Institution).
This prominent pinnacle is an eroded remnant of a tuff cone on Bartolomé Island, off the east coast of Santiago Island. A wide variety of volcanic features flanks Sullivan Bay, one of the most visited boat anchorages in the Galápagos Islands. These include tuff cones and cinder cones, a dissected solidifed lava lake, and vast fields of youthful pahoehoe lava flows.

Photo by Lee Siebert, 1978 (Smithsonian Institution).
The ropy texture of pahoehoe lava flows is produced when the thin solidified surface of the flow is pushed by the advancing, still-molten interior. This pleated pahoehoe lobe, on a lava flow at Santiago shield volcano in the Galápagos Islands, advanced slowly from the bottom right to the upper left. Pahoehoe lavas are the least viscous of common lava types, and thus form spectacular surface structures.

Photo by Lee Siebert, 1978 (Smithsonian Institution).
An extensive field of spectacular pahoehoe lava flows is located near Sullivan Bay on Santiago Island. The fresh, sparsely vegetated flows cover an area of more than 50 sq km along the SE coast of the island. Eruptions occurred at SE Santiago in 1897 and 1904-06. A small lava shield 3.5 km inland from Cabo Trenton on the SE tip of the island was the principal vent of these flows.

Photo by Lee Siebert, 1978 (Smithsonian Institution).
The elongated shield volcano of Santiago Island is dotted with Holocene pyroclastic cones. Fresh lava flows that blanket the flanks of the volcano originated from these cones. The 920-m-high summit ridge, lined with NW-trending cinder and spatter cones, is seen here from James Bay on the west side of the island. The James Bay lava flows (center) reached the coast along a broad front. They were dated by fragments of marmalade pots left by buccaneers in 1684 that were subsequently embedded in the lava flows observed by Charles Darwin in 1835.

Photo by Lee Siebert, 1978 (Smithsonian Institution).
Cabo Cowan is a tuff cone at the NW tip of Santiago Island in the Galápagos Islands. Its summit crater is breached to the SW, where wave erosion has truncated the flanks of the cone, forming vertical sea cliffs that expose its interior. The 284-m-high tuff cone was constructed by submarine eruptions where the NW-trending rift zone along the crest of Santiago shield volcano encounters the sea.

Photo by Lee Siebert, 1978 (Smithsonian Institution).
An unnamed 394-m-high cinder cone is a prominent landmark near James Bay at the western end of Santiago Island. The eruptions that constructed the cone were initially submarine, producing palagonitic tuffs. As the cone grew above sea level, subaerial explosions produced basaltic scoria that forms the upper part of the cone. A similar, but smaller cone lies immediately to the SE, out of view to the right.

Photo by Lee Siebert, 1978 (Smithsonian Institution).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

McBirney A R, Williams H, 1969. Geology and petrology of the Galapagos Islands. Geol Soc Amer Mem, 118: 1-197.

Richards A F, 1962. Archipelago de Colon, Isla San Felix and Islas Juan Fernandez. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 14: 1-50.

Simkin T, 1976. . (pers. comm.).

Swanson F J, Baitis H W, Lexa J, Dymond J, 1974. Geology of Santiago, Rabida, and Pinzon Islands, Galapagos. Geol Soc Amer Bull, 85: 1803-1810.

White W M, McBirney A R, Duncan R A, 1993. Petrology and geochemistry of the Galapagos Islands: Portrait of a pathological mantle plume. J Geophys Res, 98: 19,533-19,563.

Volcano Types

Shield
Pyroclastic cone(s)

Tectonic Setting

Rift zone
Oceanic crust (< 15 km)

Rock Types

Major
Basalt / Picro-Basalt
Minor
Andesite / Basaltic Andesite
Trachybasalt / Tephrite Basanite
Trachyandesite / Basaltic trachy-andesite
Trachyte / Trachyandesite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
74
74
104
12,001

Affiliated Databases

Large Eruptions of Santiago Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.