Santiago

Shield in Ecuador

Last Eruption: 1906

Key Facts

Elevation

920 m (3,018 ft)

Type

Shield

Location

-0.220°, -90.770°

Region

Galapagos Hotspot Volcano Group

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Rift zone

Location

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Overview

The elongated shield volcano of Santiago Island, also known as San Salvador Island or James Island, has numerous scattered Holocene pyroclastic cones. Fresh-looking lava flows from these cones cover the flanks. The 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. The most recent activity has been concentrated at the NW and SE ends of the island. The pahoehoe lava flows at James and Sullivan Bays, on opposite ends of the island, were erupted in the past few hundred years.

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.

Volcanic Hazards & Risk Assessment

Primary Hazards

Risk Level

Population at RiskModerate

Infrastructure RiskHigh

Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary

Basalt / Picro-Basalt

Silica Content

Low (45-52% SiO₂)

Tectonic Setting

Rift zone

Continental rift or intraplate setting with varied eruptive styles.

Age & Formation

Epoch

Holocene

Evidence

Eruption Observed

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	120 years ago	Historical	Historically active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program

International eruption database

Current Status

Normal

No recent activity. Routine monitoring continues.

Nearby Volcanoes in Eastern Pacific Volcanic Regions

Regional Volcanic Activity

The Eastern Pacific Volcanic Regions contains multiple active volcanic systems. Cross-regional magma interactions and tectonic stresses can influence eruption patterns across the entire arc. Monitor regional seismic activity and volcanic alerts.

Quick Info

•Smithsonian ID: 353090
•Evidence: Eruption Observed
•Epoch: Holocene

About the Photo

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).