What is the Pacific ‘Ring of Fire'?
The Pacific 'Ring of Fire,' as it has been described for more than a century, is a chain of seismologically and geologically active regions that encircle the Pacific Ocean, where many of the world's biggest earthquakes, volcanic eruptions and tsunamis occur. It spans a horseshoe-shaped area winding from New Zealand, through parts of Southeast Asia, through Japan, Alaska, down through the west coast of North and South America.
Some of the most devastating mass disasters, in recent memory and in distant history, have occurred along the ring: Japan's Fukushima disaster in 2011; the Great Chilean earthquake of 1960; the Indian Ocean earthquake and tsunami in 2004; and Alaska in 1964.
Many of the big future quakes that governments, scientists and emergency responders alike are bracing for are expected in its course — on California's San Andreas, in Japan's Nankai Trough, and on the Cascadia fault off the Pacific Northwest.
Here is what to know about the Pacific Ring of Fire.
The 'Ring of Fire' is more of a convenient, colloquial concept to describe the plate boundaries that surround the Pacific Basin, rather than scientific terminology. It began with geologists' observation that a lot of volcanoes occur along the band — hence the 'fire' — and only came to be better understood in recent decades with advancements in theories of plate tectonics as to why so much of the world's seismic activity occurred along the Pacific Rim.
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National Geographic
5 days ago
- National Geographic
Scientists didn't expect the 8.8 magnitude Russian megaquake for many more years. Why now?
Here's what we know about what caused the earthquake off Russia's Far East and why the tsunami it generated weren't as big as anticipated. The aerial view of the city of Severo-Kurilsk shows flooding due to tsunami waves triggered by the 8.8 magnitude earthquake struck off the coast of Russia's Kamchatka Peninsula. The quake struck at 11:24 a.m. local time on July 30 (9:24 p.m. eastern time on July 29), and its epicenter was 20.7 kilometers (12.8 miles) deep. Photograph by Kamchatka of Geophysical Survey/Anadolu/Getty Images Just offshore from Russian's far-eastern Kamchatka peninsula, a major earthquake shook the region on Wednesday. At magnitude 8.8, it released several times more energy than the largest nuclear bomb ever detonated. 'It's a massive-scale earthquake,' says Harold Tobin, the director of the Pacific Northwest Seismic Network at the University of Washington. In fact, Earth hasn't seen a quake this big since 2011, when a magnitude 9.1 tremblor off the coast of Japan resulted in the Fukushima nuclear disaster. 'It's within the top 10 largest earthquakes ever recorded by seismometers,' says Steven Hicks, an earthquake scientist at University College London. It didn't just cause the seafloor to jolt upward. 'It broke the seafloor,' he says. And immediately, the danger was clear: The seafloor break generated a dangerous, ocean-spanning tsunami. As a result, tsunami warnings were speedily issued for many of the countries bordering the Pacific Ocean, including the entire western seaboard of North America, as well as parts of Central and South America. (Here's what to do to prepare for a tsunami.) This earthquake took place along a tectonic schism that's known for creating truly devastating temblors and tsunamis. So far, it looks like the worst-case scenarios of widespread death and devastation haven't played out. But the tsunami could still impact various shores throughout the day, and powerful aftershocks are occurring, so the danger hasn't passed just yet. What caused this megaquake? Such extreme events are called megathrust earthquakes or megaquakes because of their sheer size and where they occur. Its epicenter falls within a geologic battleground known as a subduction zone. Here, the Pacific tectonic plate collides with and sinks below the Eurasian plate in what is known as a subduction zone. 'Where these two plates collide, the megathrust fault becomes stuck and locked, storing up the accumulated plate motion for hundreds of years,' says Hicks. 'This stored energy suddenly gets released in great earthquakes.' So, it's not surprising that a major earthquake took place off the coast of Kamchatka. 'Big quakes have happened here in the past, so with this one, we knew to expect something there,' says Christine Houser, a geophysicist at the Tokyo Institute of Technology. In response to tsunami warning, the Enoden train service was suspended in Kamakura City, Kanagawa Prefecture on July 30, 2025. Photograph by The Yomiuri Shimbun/AP Images A TV news program reports the issuance of tsunami warning at city hall as shelter after the issuance of tsunami warning in Tanabe City, Wakayama Prefecture on July 30, 2025. Photograph by The Yomiuri Shimbun/AP Images According to the U.S. Geological Survey (USGS), this was also a reverse faulting event. This involves a large block of the crust above the active fault suddenly moving up over another block of the crust below the fault. In this case, a fault line ruptured over a length of a few hundred miles in a matter of seconds, releasing as much energy as roughly 240 million tons of TNT. 'It's a big earthquake. There's no doubt about that,' says Tobin. The nearest large city was Petropavlovsk-Kamchatsky, on Kamchatka, home to over 180,000 people. At least a quarter of a million people in the region felt severe, damaging shaking, USGS estimates. There have been at least two-dozen aftershocks from this mainshock, including a magnitude 6.9 event; aftershocks like this are expected to continue for several days, at least. A possible prelude to the main event Although the megaquake's location isn't too strange, there is something unusual about its timing. Back in 1952, very close to today's colossal temblor, a highly destructive magnitude 9.0 quake struck the region—one that also generated a powerful tsunami. A gap of several decades between this megaquake and today's event may seem like a long time. But not for megaquakes. In general, for these major events, 'stress builds up, then you have a big earthquake to relieve that stress,' says Houser. And then there's a gap of perhaps several centuries. That clearly didn't happen. 'Would I have predicted another nearly-magnitude 9.0 event within only several decades? Probably not,' says Tobin. The short period between these two megathrust quakes suggests that these ginormous subduction zones can build up an explosive degree of stress over a relatively short period. And, for the time being, scientists aren't certain how this happened. 'It shows our ignorance,' says Houser. It's worth underscoring, though, that the largest of quakes don't operate according to neatly timed schedules. 'It's not a clockwork,' says Tobin. Understanding why is one of the most crucial open questions in the geosciences—an unsolved puzzle that means that, for now, nobody can predict exactly when the next major quake will take place. The first waves of the tsunami have arrived Japan's Pacific coast after the magnitude 8.7 strong earthquake strikes off Kamchatka Peninsula on July 30, 2025 in Shiogama, Miyagi, Japan. Photograph by TheCars are at a standstill along the Pan-American Highway in Panama City, Wednesday, July 30, 2025, following a tsunami warning after a earthquake struck off the coast of Russia early Wednesday. Photograph by Matias Delacroix, AP On a related note: just over a week prior, a magnitude 7.4 earthquake (which also briefly threatened to generate a tsunami) exploded along the very same subduction zone. Earthquake scientists are now speculating as to whether that significant temblor was some sort of precursor, or at least a possible warning, of today's catastrophic event. For now, 'we have no way of telling that a magnitude 7.0 will be followed at some point by a larger quake,' says Lucile Bruhat, an earthquake scientist working in the insurance industry. But there is a chance that the magnitude 7.4 quake from earlier this month 'could have triggered today's earthquake. But it will be after analyzing the slip and rupture pattern that we'll be able to confirm that assumption.' In some ways, today's magnitude 8.8 event 'is a near-repeat of the magnitude 9.0,' says Tobin. But earthquakes of similar magnitudes can release vastly different amounts of energy, and despite its only slightly higher rating, the 1952 quake was twice as energetic as today's, which goes some way to explaining why the previous event was more destructive and decidedly lethal. As frightening as that quake itself would have been, much of the concern immediately focused on the tsunami it undoubtedly unleashed. 'These shallow subduction megathrust events cause large tsunamis because the portion of fault that moves during the earthquake reaches close to, if not directly penetrates, the seafloor, displacing vast volumes of water in the sea above,' says Hicks. (Here's why no one was prepared for the deadliest tsunami in history.) Calculating the possible wave heights of tsunamis can be tricky, as the shape and depth profile of the shoreline can really affect its development from location to location. 'The wave energy is guided by the depth of the water in any given location,' says Tobin. Either way, based on the nature of the quake itself, the threat was obvious. 'Issuing a tsunami warning was absolutely right thing to do.' Nations across the Pacific were immediately placed on alert. So far, the worst-hit region is that of southeastern Kamchatka, where tsunami waves reaching a heigh of over 16 feet have been observed. Structures have been seen being washed away in some locations, although no deaths have currently been reported. 'It's a very sparsely populated region too, so there wasn't a lot in harm's way, fortunately,' says Tobin. Meanwhile, a vast volume of water was pushed out into the wider ocean, triggering evacuation notices in Japan, several Pacific islands, and, eventually, across Hawaii. In Japan, initial smaller tsunami wave had heights of around one foot. But later, waves as high as 4.3 feet were recorded, with the possibility of waves double that height possible for some shorelines. Hawaii has also seen waves several feet high. Aftershocks—including those capable of generating smaller tsunamis—will continue for some time. But even if the damage from the mainshock's tsunami is still being assessed, it seems much of the Pacific has dodged a decidedly grim fate. 'It's kind of looking like the amplitude of the tsunami is less than at least the worst-case scenarios,' says Tobin.
Scientific American
5 days ago
- Scientific American
Russia's 8.8 Earthquake Is One of the Strongest Ever Recorded
2 min read Russia's earthquake was estimated at magnitude 8.8, among the strongest since scientists began monitoring By On July 30, 2025, an 8.8 magnitude earthquake struck off the eastern coast of Russia, sending a tsunami toward that country's coast and high waves across the Pacific Ocean, from Japan to Hawaii and California. The world has witnessed several very large earthquakes in the past couple years, including a 7.7 in Myanmar in March 2025 and a 7.4 on Taiwan's east coast in April 2024. The Richter scale is logarithmic, meaning the seismic waves in an 8.0 quake are 10 times greater in amplitude than those in a 7.0 quake, with roughly 32 times more power. The 7.0 waves, in turn, are 10 times greater and 32 times more powerful than a 6.0 quake. The strongest earthquake ever recorded, a 9.5, struck Chile's southern coast in 1960. Here is a list of the most powerful earthquakes on record, from the U.S. Geological Survey, which also published the descriptions shown below. Russia's latest quake will likely be added after scientists have a chance to analyze and verify data recorded by seismographs worldwide. 9.5 Biobío, Chile, 1960. Commonly referred to as the Valdivia earthquake or Great Chilean earthquake, the largest earthquake ever, killed 1,655 people and left two million homeless. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. 9.2 Alaska, 1964. Known as the Great Alaska earthquake, the Prince William Sound earthquake, or the Good Friday earthquake, this quake and ensuing tsunami killed 130 people and caused $2.3 billion in damage. 9.1 Sumatra, Indonesia, 2004. The Sumatra-Andaman Islands earthquake triggered massive tsunamis and killed more than 280,000 people while displacing 1.1 million across South Asia and East Africa. 9.1 Tōhoku, Japan, 2001. The Great Tōhoku earthquake and subsequent tsunami killed more than 15,000 people and displaced 130,000 more. 9.0 Kamchatka Krai, Russia, 1952. The world's first recorded magnitude 9 earthquake triggered a massive tsunami that struck Hawaii, causing over $1 million in damages. 8.8 Biobío, Chile, 2010. Occurring offshore near the city of Quirihue, this intense earthquake killed 523 people and destroyed more than 370,000 homes. 8.8 Esmeraldas, Ecuador, 1906. The so-called Ecuador-Colombia earthquake produced a strong tsunami that killed 1,500 and reached as far north as San Francisco. 8.7 Alaska, USA, 1965. Located near the Rat Islands of Alaska's Aleutian Islands, this quake generated a tsunami that was reportedly 35 feet high. 8.6 Arunachal Pradesh, India, 1960. The Assam-Tibet earthquake produced intense shaking, triggered sandblows, ground cracks and large landslides across the region. All told, 780 people died. 8.6 Sumatra, Indonesia, 2012. Located off the coast of northern Sumatra, this quake produced heavy shaking, but only a handful of fatalities, mostly caused by heart attacks.
The Hill
5 days ago
- The Hill
What is the largest earthquake ever recorded?
An 8.8 magnitude earthquake — one of the most powerful in recorded history — struck off the coast of Russia Tuesday, prompting tsunami watches and warnings around the globe. But how does it measure up with the strongest earthquakes in history? The United States Geological Survey's (USGS) seismogram records only go back to about 1900, but since then there have been multiple quakes that registered at 9.0 magnitude and above. 1. Valdivia Earthquake The most powerful earthquake happened in 1960 in Biobio, Chile. The 9.5 magnitude Valdivia earthquake, also referred to as the Great Chilean Earthquake, killed some 1,655 people and left 2 million homeless, according to the USGS. 2. Great Alaska Earthquake Four years later, a 9.2 magnitude earthquake rocked Alaska, generating a tsunami that, combined with the earthquake, killed at least 130 people and caused over $2 billion in damage, according to the USGS. The earthquake was also known as the Prince William Sound earthquake, or the Good Friday earthquake. 3. Sumatra-Andaman Islands Earthquake A magnitude 9.1 earthquake that shook Sumatra, Indonesia and the Andaman Islands in 2004 caused deadly tsunamis that killed over 280,000 people and left more than 1 million displaced, according to the USGS. Prior to Tuesday's earthquake, the 10 largest earthquakes since 1900 were: 4. Magnitude 9.1 (2011). Tohoku, Japan 5. Magnitude 9.0 (1952). Kamchatka Krai, Russia 6. Magnitude 8.8 (2010). Biobo, Chile 7. Magnitude 8.8 (1906). Esmeraldas, Ecuador 8. Magnitude 8.7 (1965). Alaska, U.S. 9. Magnitude 8.6 (1950) Arunachal Pradesh, India 10. Magnitude 8.6 (2012). Sumatra, Indonesia On Tuesday, a tsunami warning was issued for Alaska, Hawaii and other coasts south toward New Zealand after the earthquake struck roughly 74 miles east-southeast of the Russian city of Petropavlovsk-Kamchatsky, which has a population of 180,000, on the Kamchatka Peninsula. Multiple aftershocks as strong as 6.9 magnitude were recorded. Several locations advised evacuations, but no major injuries have been reported. Cars jammed streets and highways in Honolulu as the tsunami alerts coincided with the Tuesday afternoon rush-hour. Warning sirens blared as people moved to higher ground. Hawaii schools canceled after-school and evening activities. A tsunami of 50 centimeters (1.6 feet) was detected at the Ishinomaki port in northern Japan, according to the Japan Meteorological Agency. That was the highest measurement so far among several locations around northern Japan. The Russian areas nearest the quake's epicenter on the Kamchatka Peninsula reported damage and evacuations, but no serious injuries.
