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MOUNT LEWOTOBI

Description

Source: NEWSX

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Context

Mount Lewotobi in Indonesia East Nusa Tenggara erupted spewing a 3,500 metre ash column & prompting orange-level aviation alerts, evacuation advisories & safety warnings for residents near active volcano.

Mount Lewotobi

Feature

Details

Location

Flores Island, East Nusa Tenggara province, Indonesia

Coordinates

Approximately 8.5° S, 122.8° E

Type

Stratovolcano (composite volcano)

Composition

Andesitic to basaltic andesite

Part of

Pacific Ring of Fire

Peaks

Two main peaks Lewotobi Lakilaki (1584 m) & Lewotobi Perempuan (1703 m)

Separation

2 km separated by a saddle of 1232 m elevation

Crater Features

Lakilaki 400 m wide open to north; Perempuan 700 m wide

Flank Cone

Iliwokar on east flank of Lewotobi Perempuan

Historical Eruptions

Lakilaki Frequent activity in 19th–20th century; Perempuan Only two historical eruptions

2024 Activity

Major eruption with ash plumes up to 8,000 m; aviation warning issued (Orange Level)

Volcanic Hazards

Ashfall, hot clouds, lava flows, lahars during rainfall

Local Response

6 km exclusion zone; facemask advisory; aviation rerouting below 5,000 m

Nearby Settlement Risk

High due to proximity of human habitation & farming communities

 

Tectonic Plates Related to Indonesia & Ring of Fire

Eurasian Plate

Feature

Details

Type

Major tectonic plate

Boundaries

Converges with Indian, Arabian & Philippine Sea plates

Interaction with Indo-Australian Plate

Subduction of Indo-Australian Plate beneath Eurasian Plate creates volcanic arcs

Relevance to Indonesia

Forms northern boundary; causes volcanism & earthquakes

Geological Significance

Part of complex Sunda Arc tectonic interaction

Australian Plate

Feature

Details

Type

Major tectonic plate

Boundary Type

Convergent (subducts under Eurasian Plate)

Motion Direction

Northward at ~7 cm/year

Interaction with Indonesia

Responsible for Sunda Trench & volcanic arc in Java-Sumatra chain

Importance

Drives seismicity in southern Indonesian region

Pacific Plate

Feature

Details

Type

Largest tectonic plate

Motion Direction

Westward movement

Plate Boundaries

Interacts with Philippine Sea, North American & Indo-Australian plates

Indonesia Relevance

Less direct than Eurasian/Australian but contributes to broader Pacific seismicity

Key Feature

Dominates Ring of Fire encircling Pacific Basin

Sunda Arc

Feature

Details

Location

Extends from northern Sumatra through Java, Bali, Lombok, Sumbawa, Flores, to Banda Sea

Tectonic Setting

Formed by subduction of Indo-Australian Plate beneath Eurasian Plate

Arc Type

Continental volcanic arc

Length

Over 3,000 km

Key Islands

Sumatra, Java, Bali, Lombok, Sumbawa, Flores, Wetar

Oceanic Feature

Lies above Sunda Trench a major subduction zone

Major Volcanoes

Mount Merapi, Mount Agung, Mount Bromo, Mount Rinjani, Mount Tambora, Mount Lewotobi

Plate Interaction

Indo-Australian Plate (subducting) & Eurasian Plate (overriding)

Volcanic Activity

High includes several of world’s most explosive & active volcanoes

Hazards

Earthquakes, tsunamis, pyroclastic flows, lahars, ashfall, volcanic lightning

Most Famous Eruption

Mount Tambora (1815) largest eruption in recorded history; caused “Year Without a Summer”

Modern Monitoring

Managed by Indonesia PVMBG (Volcanology & Geological Hazard Mitigation Centre)

Geological Importance

Vital for understanding plate tectonics, subduction volcanism & hazard mitigation

Geological & Tectonic Information

Aspect

Details

Subduction Zone

Indo-Australian Plate descends below Eurasian Plate

Trench System

Sunda Trench (a deep oceanic trench parallel to arc)

Magma Generation

Caused by water-rich oceanic crust melting in mantle wedge forming andesitic magma

Seismicity

Frequent earthquakes due to plate movement; includes megathrust & deep-focus quakes

Tsunami Potential

High especially where underwater quakes rupture sea floor (e.g., 2004 Indian Ocean Tsunami)

Banda Arc Connection

The eastern end transitions into complex Banda Arc involving multiple microplates

Economic Impact

Affects agriculture, infrastructure & human settlement due to fertile soils but high risk

Major Volcanoes of Sunda Arc

Volcano

Island

Elevation (m)

Last Major Eruption

Notes

Mount Merapi

Java

2,963

2023

Most active volcano in Indonesia

Mount Tambora

Sumbawa

2,850 (after 1815)

1815

Deadliest eruption in history

Mount Agung

Bali

3,031

2019

Known for 1963 catastrophic eruption

Mount Rinjani

Lombok

3,726

2016

Second highest in Indonesia

Mount Lewotobi

Flores

1,703 / 1,584

2024

Twin volcano, recent aviation alerts issued

For more such articles, please refer to IAS GYAN

Sources:

THEHANSINDIA

PRACTICE QUESTION

Q. Sunda Arc exemplifies dynamic interaction of tectonic plates shaping Southeast Asian geography & hazards. Examine geological significance & implications of volcanic activity along Sunda Arc for regional disaster preparedness.

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