1. The powerful quake struck at 5:58 am local time at a depth of about 10 kilometres, with its epicentre about 68 kilometres (42 miles) north-northwest of Ende in East Nusa Tenggara, according to the US Geological Survey (USGS). Indonesia’s disaster management agency said at least 51 people were killed, while dozens more were injured.
2. The earthquake triggered a tsunami warning along parts of Indonesia’s eastern coast. The warning was later lifted after monitoring showed no significant continuing threat, although the Indonesian meteorological agency recorded small tsunami waves in several coastal areas.
3. Indonesia, home to more than 270 million people spread across roughly 17,000 islands, sits on the Pacific “Ring of Fire” and is among the most seismically active countries in the world.
What is the Pacific Ring of Fire?
4. The Pacific ‘Ring of Fire’ or Pacific rim, or the Circum-Pacific Belt is essentially a semicircle or horse shoe shaped string of hundreds of volcanoes and earthquake-sites which runs along the Pacific Ocean. It is home to about 75 per cent of the world’s volcanoes – more than 450 volcanoes. Also, about 90 per cent of the world’s earthquakes occur here.
5. Its length is over 40,000 kilometres and traces from New Zealand clockwise in an almost circular arc covering Tonga, Kermadec Islands, Indonesia, moving up to the Philippines, Japan, and stretching eastward to the Aleutian Islands, then southward along the western coast of North America and South America.
What makes the Pacific Ring of Fire a tectonic hotspot?
Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire. The trenches are shown in blue-green. The volcanic island arcs, although not labelled, are parallel to, and always landward of, the trenches. For example, the island arc associated with the Aleutian Trench is represented by the long chain of volcanoes that make up the Aleutian Islands. (Source: W. Jacquelyne and Robert I. Tilling via USGS)
6. Earth’s crust and uppermost mantle consists of several tectonic plates, together referred to as the lithosphere, that are constantly moving. Around the Pacific, several of these plates interact along boundaries where they collide, slide past each other or pull apart.
7. It is important to note that the Ring of Fire is not a single geological feature or a perfectly continuous ring but largely corresponds to active plate boundaries of several tectonic plates.
8. These include Eurasian, North American, Juan de Fuca, Cocos, Caribbean, Nazca, Antarctic, Indian, Australian, Philippine, Tonga and other smaller plates, which all encircle the large Pacific Plate, according to a report by National Geographic. The movement of these plates or tectonic activity makes the area witness abundant volcanoes, earthquakes and tsunamis every year.
9. Along much of the Ring of Fire, tectonic plates move towards each other creating subduction zones (along convergent plate boundaries). The heavier plate gets pushed down or is subducted by the other plate, creating a deep trench.
10. This is a very slow process – a movement of just one or two inches per year. As this subduction happens, rocks melt, become magma and move to Earth’s surface and cause volcanic activity.
11. Most of the subduction zones on the planet are located in the Ring of Fire and that is why it hosts a large number of volcanoes. The Hunga Tonga-Hunga Ha’apai volcano in 2022 erupted because the Pacific Plate was pushed down below the Indo-Australian Plate and Tonga plate, causing the molten rock to rise above and form the chain of volcanoes.
12. Earthquakes can occur along the plate boundaries due to constant sliding past, colliding into, or moving above or below each other of the tectonic plates.
13. Most of the violent earthquakes and tsunamis on the planet occur along the Subduction zones. In these zones, as a denser oceanic plate is forced beneath another plate, stress can accumulate along the boundary and eventually be released as a powerful earthquake.
14. The 2025 Kamchatka earthquake (magnitude 8.8) is a useful case study because it showed the connection between a major subduction-zone earthquake and Pacific-wide tsunami warnings. The December 26, 2004 earthquake occurred along the subduction zone where the Indian Plate was subducted beneath the Burma plate.
15. The Indonesia disaster comes days after a 7.4-magnitude earthquake struck western Colombia — the country’s strongest this century. The earthquake was a strike-slip event, meaning the main movement occurred horizontally along a fault rather than through the subduction mechanism responsible for many of the largest earthquakes around the Pacific.
16. That distinction is important. Although Colombia is part of the broader Pacific seismic belt, not every Ring of Fire earthquake is produced by the same tectonic process.
What is plate tectonics theory?
1. The Earth’s surface is a mosaic of tectonic plates of various sizes– divided into 7 major plates and several minor ones. These rigid masses (plates) are in continuous motion as they are floating over a semi-liquid surface below, known as the asthenosphere. These dynamic plates, moving a few centimeters every year, interact with each other through convergence, divergence or by sliding past each other.
2. These interactions lead to the formation of relief features such as mountains, plateaus, plains, etc. At the same time, they also cause destruction through tsunamis, volcanoes or earthquakes.
3. The outer surface of the Earth looks solid and stable, but its interior consists of three concentric layers – crust, mantle and core – each having its own structure, composition, and behaviour.
— The crust (5–70 km thick): The uppermost layer where all forms of life and relief features are located.
— The mantle (extends to ~2,900 km depth): It is divided into the upper mantle (~700 km) and lower mantle (700-2,900 km).
* The upper mantle has been further subdivided into lithosphere (rigid, up to ~100 km) and the asthenosphere (below lithosphere up to ~700 km depth). The asthenosphere is a ductile, semi-molten zone where convection currents move plates.
— The core (~2,900-6,371 km): It extends to the Earth’s centre and is composed of iron and nickel.
Types of plate boundaries:
(i) Convergent boundaries: At Convergent boundaries, crust is destroyed as denser plate sinks under less denser plate. This process is called subduction. Oceanic Plates are denser compared to continental plates and can form the deepest Earth features called trenches.
(ii) Divergent boundaries: At divergent boundaries, tectonic plates pull away from each other, giving rise to new crust.
(iii) Transform boundaries: They are formed when two plates move horizontally and slide past one another.
BEYOND THE NUGGET: Mantle Plume Theory
1. Most volcanism associated with the classic Ring of Fire is linked to subduction at convergent plate boundaries. Apart from dynamics of plate tectonics, some volcanic activity is also attributed to mantle plumes.
2. These are upwellings of abnormally hot mantle materials rising deep within the earth. As per scientific evidence, they are thought to be hotter than the surrounding asthenosphere.
3. There is still a scientific uncertainty over their real nature and origin (whether they rise from the shallow asthenosphere or deep core–mantle boundary).
4. Irrespective of this, mantle plumes generate large volumes of magma over an area. The Hawaiian–Emperor seamount chain is the classic example used to explain hotspot/mantle-plume volcanism.
5. Large Igneous provinces are widely hypothesised to form through massive episodes of mantle melting, potentially associated with mantle plumes. The Deccan Traps, one of the world’s largest continental flood-basalt provinces, are widely linked to the Réunion hotspot and its interaction with the Indian Plate around 66 million years ago.
Post Read Questions
(1) Consider the following statements:
Statement-I: Subduction zones are particularly prone to producing very large earthquakes.
Statement-II: At a subduction zone, the interface between the descending and overriding plates can remain locked despite continuous plate convergence, allowing stress to accumulate.
Which one of the following is correct?
A. Both Statement-I and Statement-II are correct, and Statement-II is the correct explanation for Statement-I.
B. Both Statement-I and Statement-II are correct, but Statement-II is not the correct explanation for Statement-I.
C. Statement-I is correct, but Statement-II is incorrect.
D. Statement-I is incorrect, but Statement-II is correct.
(2) With reference to plate boundaries, consider the following statements:
1. New oceanic crust is generally created at divergent boundaries.
2. Oceanic crust may be destroyed at convergent boundaries through subduction.
3. Transform boundaries are characterised primarily by vertical movement of one plate beneath another.
4. Earthquakes can occur at all three major types of plate boundaries.
Which of the statements given above are correct?
(a) 1 and 3 only
(b) 1, 2 and 4 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4
Answer key: 1. (a), 2.(b)
(Sources: Indonesia, Colombia, Venezuela rocked by massive earthquakes: Is Ring of Fire waking up?, Explained: What is the Pacific ‘Ring of Fire’?, Knowledge Nugget | Africa’s Dramatic Geological Transformation: What is the latest research on this, and how is it a UPSC must-read?)
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Pacific Ring of Fire is a striking reminder that beneath Earth’s seemingly stable surface, the planet is constantly in motion. (Image source: AI generated) 
Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire. The trenches are shown in blue-green. The volcanic island arcs, although not labelled, are parallel to, and always landward of, the trenches. For example, the island arc associated with the Aleutian Trench is represented by the long chain of volcanoes that make up the Aleutian Islands. (Source: W. Jacquelyne and Robert I. Tilling via USGS)
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