Are all these earthquakes the percursor to 'the big one?'
A series of minor earthquakes have been shaking the Pacific Northwest, with the latest tremors felt in Auburn, Bremerton, and Fall City. The quakes, including one nearly reaching a magnitude of 3.0, have prompted residents to question their significance.
Harold Tobin, director of the Pacific Northwest Seismic Network, joined 'Seattle's Morning News' with Charlie Harger Friday.
'We often experience magnitudes of 3 to 3.5, which are enough to get people's attention but not cause damage,' Tobin emphasized. 'I do not see them as showing me any sign that they're leading up to something bigger.'
MyNorthwest related: Yet another earthquake, this one near Fall City
Earthquake fault lines crisscross the region
Tobin noted numerous fault lines, including the Seattle Fault, the Southern Whidbey Island Fault and the Tacoma Fault, crisscross the region.
'Our region is crisscrossed by many of these fault lines that sit below our feet,' he explained.
However, the small size and depth of these recent quakes make linking them to specific faults challenging.
'It's hard for us to tie ones this small to any specific fault,' Tobin added.
The Pacific Northwest's earthquake early warning system, ShakeAlert, successfully detected these events. 'The system is working as designed,' Tobin said. Although the system did not issue widespread alerts due to the minor quakes, it demonstrated its capability to provide warnings for more significant events. Residents are encouraged to download the MyShake app for additional information and alerts.
MyNorthwest related: 2.9 magnitude earthquake strikes Kitsap County
Ways to be prepared
Tobin reminded the public of the importance of earthquake preparedness, citing the 24th anniversary of the Nisqually earthquake, which caused significant damage in 2001.
'We must be ready for larger earthquakes, even though they come without warning,' he said.
Tobin said people can also download an app called MyShake, which warns about smaller earthquakes.
For more information on earthquake preparedness and early warning systems, visit the Pacific Northwest Seismic Network's website.
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NBC News
31-07-2025
- NBC News
Minimal U.S. effects from tsunami don't mean the forecast was inaccurate
The magnitude-8.8 earthquake off the coast of Russia's Kamchatka peninsula sent a wave of water racing at the speed of a jetliner toward Hawaii, California and Washington state, spurring warnings and alarm overnight on Wednesday. But when the tsunami waves arrived, they didn't cause devastation or deaths in the U.S. and the inundation might not have appeared threatening in some locations where warnings were issued. That doesn't mean the tsunami was a "bust," that it was poorly forecast or that it didn't pose a risk, earthquake and tsunami researchers said. 'You start to hear tsunami warning and everyone immediately thinks of the last Hollywood movie they saw and then it comes in at 3 feet and people are like, 'What's that?'' said Harold Tobin, the director of the Pacific Northwest Seismic Network and a professor at the University of Washington. 'We should count it as a win that a tsunami occurred, we got a warning and it wasn't the worst-case scenario.' Here's what to know. How strong was the Kamchatka earthquake? And why did it change so much? The initial reports of the Kamchatka earthquake from the United States Geological Survey pegged it as a 8.0-magnitude. Later, it was upgraded to an 8.8 magnitude quake. 'That is not uncommon for very, very large earthquakes in those initial minutes,' Tobin said. 'Our standard algorithms for determining the size of an earthquake quickly saturate. It's like turning up an amp and getting a lot of distortion." One of the first signs the earthquake was stronger than the initial seismic reports was an initial measurement from a buoy about 275 miles southeast of the Kamchatka peninsula. The buoy, which is part of the National Oceanographic and Atmospheric Administration's DART (Deep-ocean Assessment and Reporting of Tsunamis) system, is connected to a seafloor pressure sensor about 4 miles below the surface. The sensor registered a 90-centimeter wave, which is eye-popping to tsunami researchers. 'That's the second-largest recording we ever saw in the tsunami world,' said Vasily Titov, a senior tsunami modeler at NOAA's Pacific Marine Environmental Laboratory, adding that it indicated there was 'a catastrophic tsunami propagating in the ocean.' Titov said the only higher reading was from the 2011 Tōhoku earthquake and tsunami, which caused nearly 16,000 deaths in Japan. Seismic models later confirmed that Wednesday's earthquake was a magnitude-8.8, which means it released nearly 16 times as much energy as a magnitude-8.0 earthquake, according to a USGS calculation tool. Tōhoku was much bigger. Tobin estimated that earthquake released 2-3 times as much energy as was observed in Kamchatka. Titov said the tsunami in Japan was also about three times larger. Additionally, Tobin said the Tōhoku earthquake 'produced an anomalously large seafloor displacement,' lurching and moving more water than expected, even for an earthquake of its magnitude. At Kamchatka, 'it's likely that there was less seafloor displacement than could have happened in a worst case or more dire scenario for a magnitude 8.8,' Tobin said, though more research will be needed to confirm that theory. How did researchers make a forecast? How good was the forecast? In two hours' time, researchers produced a tsunami forecast for 'pretty much the whole Pacific and for warning points along the U.S. coastlines,' Titov said, with predictions of water levels at coastal tide gauges and also for flood inundation. The tsunami took about eight hours to reach Hawaii and 12 hours to reach the California coast. Titov, who helped build the models used by forecasters who issue warnings from the National Tsunami Warning Centers in Hawaii and Alaska, said the models rely on seismic data and the network of nearly 80 DART buoys in place along the Pacific Rim, which sense pressure changes. The U.S. owns and operates about half of the DART buoys. Titov said the models indicated that north shore areas of Hawaii would receive tsunami waves of about two meters or less. 'Hilo was predicted at about still two meters [6.5 feet] and it materialized at about 150 centimeters,' or 1.5 meters [5 feet], Titov said. 'It's exactly how we want it — a little bit on the conservative side.' The same trend played out in parts of California, Titov said. It will take some time to assess how well the models predicted inundation because reports are still coming in about the extent of flooding. 'We know that the flooding occurred at Hawaii. We don't know exactly the extent, but from the reports that I saw on TV, it looks like exactly what we predicted,' Titov said. Why were people in Hawaii evacuated for a five-foot wave? Yong Wei, a tsunami modeler and senior research scientist at the University of Washington and the NOAA Center for Tsunami Research, said a 1.5 meter [5 foot] tsunami wave can be very dangerous, particularly in shallow waters off Hawaii. Tsunami waves contain far more energy than wind waves, which are far shorter in wavelength, period (time between waves) and slower in speed. Wei said tsunami waves of the size that struck Hawaii can surge inland 'tens of meters,' produce dangerous currents and cause damage to boats and other moveable objects. 'People die. If they stay there and they don't get any warning, two meters can definitely kill people,' Wei said. 'If you're on the beach, strong currents can definitely pull you out into the ocean and people will get drowned.' Tobin said the initial warnings were conservative, but appropriate, in his view. 'I don't want people to think, oh, we had a warning and nothing much happened and poo poo it — 'I can ignore it,'' Tobin said. 'Warnings by nature have to err a bit on the side of caution.' Was this a historic event? No. The Kamchatka peninsula has a long history of earthquakes. 'This was an area that was ready for another earthquake and there had been a lot of earthquakes in that region over the last few weeks,' said Breanyn MacInnes, a professor in the Department of Geological Sciences at Central Washington University, which indicates increased risk. In 1952, before scientists had a strong understanding of plate tectonics, a 9.0-magnitude earthquake struck offshore of the Kamchatka peninsula in much the same region, sending a tsunami into the town of Severo-Kurilsk. 'People in Russia were not really prepared for it. It was very big earthquake, a big tsunami and they were caught off guard,' MacInnes said. MacInnes said the tsunami produced was between 30 and 60 feet in height in southern parts of the peninsula. 'Thousands of people were killed and basically the town was destroyed,' said Joanne Bourgeois, an emeritus professor of sedimentology at the University of Washington, who has been studying the region's earthquake history for about three decades. How would the tsunami warning system perform if the earthquake struck closer to home? The Kamchatka tsunami is a megathrust earthquake produced along large subduction zone fault, when one tectonic plate is forced beneath another. The U.S. west coast features a similar fault, called the Cascadia subduction zone, which runs offshore along the U.S. West Coast from Northern California to northern Vancouver Island. 'This is kind of a mirror image across the Pacific,' Tobin said. 'An 8.8 at a relatively shallow depth in Cascadia is definitely in the realm of scenarios. We could have a similar event here.' In fact, Cascadia has the potential to produce much larger quakes, Tobin said. Modeling suggests Cascadia could produce tsunami waves as tall as 100 feet. Subduction zone earthquakes typically produce tsunamis that reach shore in about 30 minutes to an hour, Titov said, which would strain forecasters' capabilities to predict tsunami effects precisely along the U.S. west coast before inundation happened. Titov said more seafloor sensors, more computer processing and innovation with artificial intelligence algorithms are needed to speed forecasting. Tobin said the successful tsunami warning on Tuesday should spur investment in seafloor sensors and seismic monitoring stations offshore along the subduction zone. 'This shows the value and importance of NOAA and the USGS [U.S. Geological Survey] in these times where some of these government agencies have come into question,' Tobin said. 'We wouldn't have had a tsunami warning if it weren't for NOAA and the next one could be a closer event. They showed their value.'
USA Today
30-07-2025
- USA Today
What makes coastal California's Crescent City so vulnerable to tsunamis?
Crescent City, California, residents are breathing a sigh of relief after its latest tsunami warning was downgraded to an advisory. Crescent City, a redwood-tree lined coastal California community, is known as the tsunami capital of the country. The city has experienced more than three-dozen tsunamis in the last century. Once again, tsunami waves ‒ luckily modest this time ‒ reached the town, peaking as high as 4 feet near city shores before dawn on July 30, according to the National Weather Service. The waves came just hours after an 8.8-magnitude earthquake, one of the strongest tremblors in recorded history, struck off Russia's east coast, prompting tsunami waves in Hawaii and along the West Coast. "It was a long night for all of us. We were fortunate this time," Crescent City Manager Eric Weir said during a morning briefing on July 30. "There was significant tsunami surges. We're still dealing with those now, but it did stay within the banks." The July 29 tsunami warning was initially expected to last as long as 30 hours in Crescent City, according to the National Oceanic and Atmospheric Administration. Weir said the waves caused significant damage to a harbor dock as it lifted decking off the pilings, but the rest of the city was spared. "Downtown is at a high enough elevation that it is open," Weir said, about an hour before the tsunami warning was downgraded to an "advisory" for Crescent City, one of the last West Coast communities considered still at risk. City officials still advised locals to stay away from the harbor, beaches and waterways due to continued wave activity. "Conditions have started to improve," city officials said in a Facebook post. "But the ocean is still angry." Coastal calm: Tsunami evacuation orders lifted in Hawaii, threat to West Coast eases Crescent City's deadly tsunami history What makes Crescent City, a town of about 6,700 residents located about 25 miles south of the Oregon border, so tsunami-prone? Crescent City is vulnerable because it is located near the southern end of the Cascadia Subduction Zone, a major fault line capable of producing dangerous tsunamis and intense earthquakes, according to the Pacific Northwest Seismic Network. Several published studies also indicate that a Cascadia Subduction Zone tsunami can cause severe damage and inland flooding. In 2011, the earthquake in Japan spurred waves of more than 8 feet, destroying Crescent City's harbor. "The water went out to a low tide, but each wave was coming back in and it was getting higher and higher," Max Blair, 79, a volunteer at the Del Norte Historical Society located near downtown Crescent City, recalled to USA TODAY on July 30. "The harbor was a whole different story." One man died during the incident as the harbor docks were smashed and dozens of boats sank, causing an estimated $50 million in damage. The harbor was eventually rebuilt as the first "tsunami resistant port" on the West Coast. Another deadly tsunami struck Crescent City in 1964, triggered by a massive earthquake in Alaska, killing 11 people and injuring 35 others. The tsunami destroyed nearly 300 buildings and homes, causing between $11 million and $16 million in damages. The incident is considered one of the most devastating tsunamis in U.S. history. "I've heard and read about it," said Blair who's lived in Crescent City for more than 30 years. "I hope we never get to experience anything like that one."
National Geographic
30-07-2025
- 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.
