🌋VolcanoAtlas

Gamalama

The Spice Island Volcano — 500 Years of Documented Eruptions

Elevation

1,714 m

Last Eruption

2018

Type

Stratovolcano(es)

Country

Indonesia

Location

Loading map...

Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows
  • Lava flows
  • Volcanic bombs and ballistics
  • Lahars and mudflows

Risk Level

Population at RiskHigh
Infrastructure RiskHigh
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Unknown
Silica Content
Varied composition

Tectonic Setting

Unknown
Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch
Unknown
Evidence
Unknown

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity8 years agoVery RecentCurrently active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Active
Recent volcanic activity detected. Continuous monitoring in place.

Authority Sources

Smithsonian GVP
Official volcano database

Related Volcanoes

All Indonesia Volcanoes
Explore by country
Stratovolcano(es) Volcanoes
By volcano type
North Maluku, Halmahera Volcanic Arc
Regional volcanoes

Other Volcanoes in Indonesia

Interesting Facts

🌋

Gamalama's 84 recorded eruptions since 1510 give it one of the longest and most complete eruption histories of any volcano in Southeast Asia, thanks to over 500 years of colonial and post-colonial documentation.

🌋

The entire island of Ternate — approximately 10 km in diameter — is composed of the single Gamalama stratovolcano, with approximately 220,000 people living on its flanks.

🌋

Ternate was the world's primary source of cloves for centuries, and European wars were fought over this tiny volcanic island, making Gamalama the geological foundation of the global spice trade.

🌋

Alfred Russel Wallace formulated his theory of natural selection in 1858 while staying on Ternate, making Gamalama the volcanic backdrop to one of the most important moments in the history of biology.

🌋

Between 1838 and 1849, Gamalama erupted 11 times in 12 years — the most intense sustained period of activity in its 500-year record.

🌋

Gamalama sits on a rare double subduction zone where the Molucca Sea Plate is being consumed from both sides simultaneously — one of only a few active examples of such a tectonic configuration on Earth.

🌋

The Ngade maar on Gamalama's southern flank formed approximately 14,500–13,000 years ago and now contains a popular crater lake used for recreation by Ternate residents.

🌋

In a major eruption, the entire population of Ternate (~220,000) would need to be evacuated by sea — there is no land route off the island — presenting one of the most challenging volcanic evacuation scenarios in Indonesia.

🌋

Three progressively younger summit cones, aligned north to south, give Gamalama an unusual triple-peaked summit profile visible from the Molucca Sea.

🌋

Only four flank eruptions have been recorded in Gamalama's history (1763, 1770, 1775, and 1962–63) — the vast majority of its 84 eruptions have originated from the summit craters.

🌋

The 19th century was Gamalama's most active period, with 25 eruptions — averaging one every 4 years throughout the century.

🌋

Gamalama's eruption record has never exceeded VEI 3, suggesting a characteristically moderate eruption style — but the pre-1510 geological record remains largely unstudied.

Frequently Asked Questions

Is Gamalama Volcano still active?
Yes, Gamalama is one of Indonesia's most active volcanoes. It has produced 84 recorded eruptions since 1510, most recently in October 2018. The volcano is continuously monitored by Indonesia's PVMBG (Center for Volcanology and Geological Hazard Mitigation), which maintains seismic and visual observation stations on and around the volcano. Gamalama's eruption frequency — averaging approximately one eruption every 6 years over its 500-year record — means that further eruptions are considered essentially certain. The volcano continues to produce volcanic earthquakes and periodic increased fumarolic activity, and alert levels are adjusted as conditions change.
When did Gamalama last erupt?
Gamalama's most recent eruption occurred on October 4, 2018, classified at VEI 1, with an ash eruption from the summit crater. Prior to that, eruptions occurred in August 2016 (VEI 1), July 2015 (VEI 2), December 2014 (VEI 2), September 2012 (VEI 1), and December 2011 (VEI 2). This pattern of frequent small eruptions is characteristic of Gamalama, which has averaged roughly one eruption every 6 years over its 500-year historical record. The most significant recent eruptions were the VEI 3 events in 1983 and 1990.
How many people live on Gamalama?
Approximately 220,000 people live in the city of Ternate and surrounding settlements on Gamalama's flanks. The city encircles the base of the volcano, with residential areas, government buildings, a university, the main commercial district, the airport, and the port all situated on the lower slopes and coastal lowlands. This makes Gamalama one of the most densely populated volcanic islands in Indonesia and one of the highest-risk volcanic settings in the world. Evacuation in a major eruption would require transport by sea to neighboring islands — a massive logistical undertaking.
What type of volcano is Gamalama?
Gamalama is classified as a stratovolcano (composite volcano), built from alternating layers of lava flows and pyroclastic (explosive) deposits. It has a near-conical shape that forms the entire island of Ternate, approximately 10 km in diameter. The summit features three cones of progressively younger age aligned north to south, with the northernmost cone hosting the currently active craters. Gamalama produces andesitic to basaltic andesitic magma typical of subduction zone volcanism. Its eruptions are characteristically moderate (VEI 1–3), involving explosive ash columns, ashfall, and occasional lava flows rather than the catastrophic Plinian eruptions seen at some other stratovolcanoes.
Can you hike Gamalama?
Yes, the summit of Gamalama can be hiked when volcanic alert levels permit. The standard route starts from the village of Marikurubu or Tabala on the eastern flank and takes approximately 3–5 hours to ascend to the 1,714 m (5,623 ft) peak. The trail passes through clove plantations, tropical forest, and barren volcanic terrain to the crater rim, which offers panoramic views of the Molucca Sea, Halmahera, Tidore, and other volcanic islands. A local guide is strongly recommended. Summit access may be restricted during periods of elevated volcanic alert, so hikers should check current PVMBG alert levels. Ternate is accessible by domestic flights from Manado, Makassar, and Jakarta.
Why is Ternate historically important?
Ternate, the island formed by Gamalama volcano, was the epicenter of the global spice trade for centuries. Cloves were native to the Moluccas (Spice Islands), and Ternate was the world's primary source. Portuguese traders arrived in 1512, followed by the Spanish and Dutch, who fought wars over control of this tiny volcanic island. The Sultanate of Ternate, one of the oldest Islamic sultanates in Southeast Asia (established ~1257), was a powerful regional kingdom. In 1858, the naturalist Alfred Russel Wallace wrote his famous paper on natural selection while staying on Ternate — a foundational moment in the history of evolutionary biology.
How dangerous is Gamalama?
Gamalama poses a significant risk primarily due to population exposure rather than exceptional eruptive power. While its recorded eruptions have not exceeded VEI 3, approximately 220,000 people live on the volcano's flanks with no land-based evacuation route — the only escape is by sea. Hazards include ashfall (affecting the entire island even in moderate eruptions), ballistic projectiles near the summit, pyroclastic density currents, and lahars during heavy rainfall. The concentration of all critical infrastructure — airport, port, hospitals, government — on a single volcanic island creates a scenario where even a moderate eruption could have outsized humanitarian and logistical consequences.
What is the double subduction zone beneath Gamalama?
Gamalama sits on the Halmahera volcanic arc, which is generated by one of the rarest tectonic configurations on Earth: a double subduction zone. The Molucca Sea Plate, a remnant oceanic plate trapped between the Philippine Sea Plate and the Eurasian Plate, is being subducted from both its western and eastern margins simultaneously — westward beneath the Sangihe arc and eastward beneath the Halmahera arc. This means the Molucca Sea Plate is essentially being consumed from both sides, a process that will eventually cause it to disappear entirely. This unusual tectonic setting generates the magma that feeds Gamalama and the other volcanoes of the Halmahera arc.