Kavachi

The Pacific's Most Active Submarine Volcano

Elevation

-20 m

Last Eruption

2014 (uncertain activity to 2024)

Type

Submarine Stratovolcano

Country

Solomon Islands

Location

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Volcanic Hazards & Risk Assessment

Primary Hazards

Pyroclastic flows
Lava flows
Volcanic bombs and ballistics
Lahars and mudflows

Risk Level

Population at RiskLow

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

Metric	Value	Global Ranking	Significance
Total Recorded Eruptions	Unknown	Low	Moderately active volcano
Maximum VEI	VEI Unknown	Minor	Local impact potential
Recent Activity	-20139998 years ago	Very Recent	Currently 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 Solomon Islands Volcanoes

Explore by country

Submarine Stratovolcano Volcanoes

By volcano type

Western Province

Regional volcanoes

Other Volcanoes in Solomon Islands

Tinakula
Stratovolcano

Interesting Facts

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Kavachi has erupted at least 34 times since 1939, giving it an average recurrence interval of roughly 2.5 years — one of the highest eruption frequencies of any volcano on Earth.

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During eruptions, Kavachi has built ephemeral islands up to 1 km long that are rapidly eroded back below sea level by wave action.

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In 2015, scientists discovered hammerhead sharks, silky sharks, and stingrays living inside Kavachi's active volcanic crater, earning it the nickname 'Sharkcano.'

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The volcano is named for a sea-god of the Gatokae and Vangunu peoples of the Solomon Islands.

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Kavachi's summit sits approximately 20 m below sea level during quiescent periods, but breaches the surface during vigorous eruptions.

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The volcanic edifice rises from depths of over 1,100 m, meaning the total height of the volcanic structure from base to summit exceeds 1 km.

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Indigenous residents of nearby islands described 'fire on the water' before the first formally recorded eruption in 1939, indicating older unrecorded eruptions.

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Kavachi's eruptions are classified as Surtseyan — a type of phreatomagmatic activity driven by the interaction of hot magma with seawater.

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Lava flows have been observed on several of Kavachi's ephemeral islands, suggesting that a permanent island could eventually form if eruption rates outpace wave erosion.

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The volcano has no permanent monitoring equipment — surveillance relies on satellites, passing ships, and reports from local fishing communities.

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The alternative name 'Rejo te Kvachi' translates as 'Kavachi's Oven' in the local language.

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Kavachi's 1952–1953 eruption produced the largest known ephemeral island at the site, reportedly reaching approximately 1 km in length.

Frequently Asked Questions

Is Kavachi still active?

Yes, Kavachi is one of the most active submarine volcanoes on Earth. It has produced at least 34 recorded eruptions since 1939, with the most recent confirmed eruption in January 2014 and uncertain activity detected by satellite between 2020 and 2024. The volcano erupts on average every 2.5 years, and its activity shows no signs of diminishing. The absence of permanent monitoring means that additional eruptions may have occurred undetected. Kavachi's persistent activity makes it a textbook example of shallow submarine volcanism.

What is the 'Sharkcano'?

Kavachi earned the nickname 'Sharkcano' in 2015 when a NASA-funded expedition deployed underwater cameras into the volcano's active summit crater and discovered sharks — including scalloped hammerheads, silky sharks, and sixgill stingrays — living within the warm, acidic volcanic waters. The discovery challenged assumptions about marine life's tolerance for extreme volcanic conditions and generated worldwide media attention. The term 'Sharkcano' quickly went viral and made Kavachi one of the most recognizable submarine volcanoes in popular culture.

Has Kavachi ever formed an island?

Yes, Kavachi has repeatedly built ephemeral islands above the ocean surface during vigorous eruptions. The largest known island, formed during the 1952–1953 eruption, reportedly reached approximately 1 km in length. However, none of these islands have persisted permanently — wave erosion rapidly dismantles the unconsolidated volcanic debris once eruptive activity ceases. Islands have formed and disappeared many times since 1939. Lava flows observed on some ephemeral islands could theoretically provide more durable material, but to date no island has survived long-term.

Where is Kavachi located?

Kavachi is located in the Solomon Sea, approximately 30 km south of Vangunu Island in the Western Province of the Solomon Islands. Its coordinates are approximately 8.991°S, 157.979°E. The volcano lies within the Melanesian volcanic arc in the southwestern Pacific, part of the broader Ring of Fire. The nearest inhabited islands are Vangunu and Nggatokae (Gatokae), whose residents have observed the volcano's activity for generations.

How deep is Kavachi?

Kavachi's summit sits approximately 20 m (66 ft) below sea level during quiescent periods, though this depth fluctuates with eruptive activity. The base of the volcanic edifice rests on the seafloor at depths of 1,100–1,200 m on the northern flank, with even greater depths to the southeast. This means the total height of the Kavachi volcanic structure from base to summit exceeds 1 km — comparable to many terrestrial volcanoes — even though the entire structure is submerged.

Is Kavachi dangerous?

Kavachi poses moderate hazards, primarily to maritime traffic and fishing vessels that transit the waters above the volcano. Submarine explosions can produce sudden jets of hot water, steam, and incandescent lava bombs without warning. Ephemeral islands create temporary navigation hazards, and floating pumice can damage boats. For communities on nearby Vangunu and Gatokae islands, approximately 30 km away, the primary risk is to fishermen rather than settlements. No fatalities have been recorded from Kavachi's eruptions, but the possibility of unwarned explosive events makes the area inherently hazardous.

Why do sharks live in an active volcano?

The sharks discovered in Kavachi's crater in 2015 are thought to be attracted by the warm, nutrient-rich waters produced by hydrothermal venting within the volcanic crater. The chemically enriched waters support microbial communities that form the base of a food chain attracting larger marine life. How these animals tolerate the acidic conditions, elevated temperatures, and periodic volcanic eruptions remains an active area of research. Scientists hypothesize that the sharks may detect precursory changes and evacuate before major eruptions, or that they simply tolerate conditions that appear extreme by human standards.

How often does Kavachi erupt?

Kavachi erupts approximately every 2.5 years on average, based on 34 recorded eruptions since 1939. This makes it one of the most frequently erupting volcanoes on Earth. However, the true eruption frequency may be even higher, as the lack of permanent monitoring means that some submarine eruptions — particularly smaller events that do not breach the surface — may go undetected. There was essentially continuous activity during certain periods, such as the late 1970s, when eruptions were recorded nearly every year.