Roughly 90% of the world's earthquakes occur along this 40,000-kilometre horseshoe
Including every recorded magnitude-9 event: Chile 1960, Alaska 1964, Sumatra 2004, Tohoku 2011
Geography · Physical geography
The Ring of Fire
The Pacific Ocean rim — from New Zealand through Asia and the Americas to Chile
A horseshoe of subduction zones, volcanic arcs and deep trenches some 40,000 kilometres long around the rim of the Pacific. About three-quarters of the world's active and dormant volcanoes lie along it and roughly 90% of the world's earthquakes happen there, including every recorded magnitude-9 quake. It is a horseshoe rather than a ring: it is broken at the Drake Passage and around the Antarctic.
How to spot them
- ▸Where about 90% of the world's earthquakes and three-quarters of its volcanoes occur
- ▸Quiz clue: 'subduction', 'Benioff zone', 'Cascadia', 'Kamchatka', 'Tohoku'
- ▸A 40,000 km horseshoe, not a closed circle
- ▸Every magnitude-9 earthquake ever recorded has occurred on it
Key facts
About three-quarters of the world's active and dormant volcanoes stand on it
Fuji, Krakatoa, Pinatubo, St Helens, Popocatépetl and Rainier among them
It exists because oceanic plates are being forced under continental ones all round one ocean
Subduction melts the descending slab's overlying mantle, feeding the volcanic arcs above
The inclined plane of earthquakes that traces each descending slab bears a 20th-century seismologist's name
The Wadati–Benioff zone, after Kiyoo Wadati and Hugo Benioff
The largest earthquake ever instrumentally recorded, magnitude 9.5 in 1960, struck on it (1960)
The Valdivia earthquake in Chile, which sent a tsunami across the Pacific to Japan
The world's deepest ocean trenches lie along its western side
The Mariana, Tonga, Kuril–Kamchatka and Philippine trenches
Despite the name it is not closed — a gap in the south breaks the circuit
The Drake Passage and the Scotia Sea interrupt it between South America and Antarctica
Quick-fire facts
- •It is about 40,000 km long and traces the rim of the Pacific through some 15 countries
- •Roughly 90% of the world's earthquakes and about 75% of its volcanoes are on it
- •It is caused by subduction at convergent plate boundaries, chiefly around the Pacific Plate
- •The Wadati–Benioff zone is the sloping band of earthquake foci marking a subducting slab
- •All four recorded magnitude-9.0-plus earthquakes — 1960 Chile, 1964 Alaska, 2004 Sumatra, 2011 Tohoku — occurred on it
- •The deepest ocean trenches, including the Mariana, lie along its course
- •The Cascadia subduction zone off Oregon and Washington is its most-watched quiet stretch, last rupturing in January 1700
- •Common misconception: it is a horseshoe, not a ring — it is broken in the south — and it is not a single fault but a chain of separate plate boundaries
Drill it — 8 cards
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Sources
- NOAA National Centers for Environmental Information — Natural Hazards Data and Information
- Lee Siebert, Tom Simkin and Paul Kimberly — Volcanoes of the World