An earthquake measuring 8.8 magnitude struck off Russia’s eastern seaboard on 29 July, setting off tsunami warnings and watches across a vast stretch of the Pacific. The tremor, one of the strongest recorded in recent history, immediately prompted emergency protocols in places like Hawaii, Alaska, and along the west coast of the United States.
In Hawaii, sirens and emergency messages were sent out as officials warned of potential flooding in coastal and low-lying areas. People were urged to evacuate to higher ground. Similar alerts rippled across the Pacific, reaching as far as Japan, Russia’s Kamchatka Peninsula, and even countries in Latin America and Southeast Asia.
Understanding tsunami warnings: What each alert means
The alerts have been issued in varying forms, depending on the region's risk level.
Also Read: Powerful 8.7 earthquake off Kamchatka triggers tsunami alerts across Pacific coastlines
Hawaii, Japan and Russia already seeing impacts
The first tsunami waves have already reached Hawaii, and some may be as high as 10 feet above normal. Hawaii Governor Josh Green said residents should leave coastal zones "right away" as waves could "wrap around the islands".
Russia’s Kamchatka Peninsula was hit soon after the quake. In Severo-Kurilsk, multiple tsunami waves swept through, damaging infrastructure and even collapsing a kindergarten building. No injuries have been reported, but the district declared a state of emergency, according to TASS.
In Japan, tsunami waves have already landed along the eastern coast. These range from Hokkaido in the north to Honshu, including areas near Tokyo. So far, the waves have been relatively small, measuring around 60 centimetres. Still, over 1.9 million people across 21 prefectures are under evacuation advisories. Photos from Hokkaido show residents gathering on rooftops for safety.
Elsewhere, countries including Chile, Peru, Mexico, Panama, Taiwan, Indonesia and the Philippines have also issued tsunami alerts.
Also Read: Millions at risk: Inside the deadly 'Ring of Fire' that could trigger Earth’s next big disaster
Why tsunamis are so dangerous
Tsunami waves don’t behave like regular waves. They can look like fast-moving floods, surging inland over several minutes and then retreating, only to return again. These events can last for hours and hit without warning.
“A tsunami wave is extremely different than your typical ocean wave … it’s very much just like a torrent of floodwater coming at you at the coastline,” said Helen Janiszewski, assistant professor in the Department of Earth Sciences at the University of Hawaii at Mānoa, speaking to CNN.
She added, “Water moving quickly can really knock a person down quite easily. You don’t need a lot of it. And so it’s very, very dangerous.”
Janiszewski also warned that the impact depends heavily on local geography. "It’s not just the coastlines that are facing the direction the wave is coming from … there may actually be very complicated patterns as it arrives."
How tsunamis form and travel
Tsunamis are triggered when the ocean floor is suddenly displaced, often by an earthquake, volcanic eruption or landslide. That massive shift in water travels outward across the ocean at high speeds. In deep water, tsunami waves aren’t very noticeable. But when they approach the shore, they slow down and rise up dramatically.
According to the US National Weather Service, waves can appear as a fast-rising flood or a tall wall of water. In some cases, the water pulls back from the coast first, creating an eerie low tide effect before crashing back in.
Crucially, tsunamis are not single events. They often arrive as a series of waves that can flood, recede, and reflood land over hours. Large tsunamis can reach more than a mile inland.
Also Read: Tsunami warning today: Check countries and regions that are under high wave alert after 8.7 earthquake hits Russia's Kamchatka
What happens in Hawaii could indicate broader impact
Harold Tobin, a seismologist at the University of Washington, said the Hawaii response could offer a glimpse of what’s to come elsewhere. “What will be seen in Hawaii in the upcoming hours will be a test of what we might expect around the rest of the Pacific rim,” he told CNN.
He pointed out that some offshore quakes release energy outward into the ocean rather than back toward land. If this one follows that pattern, “then that will be a real win for everyone.”
“It could scale anywhere from really not any significant damage at all at long distances, to significant damage in areas that are right at coastal levels,” Tobin added.
“It’s important to emphasize people don’t need to panic if they’re far away from the shoreline or more than a few meters above sea level for most distant regions. But right at the shoreline in harbours, marinas, and coastal towns, that’s where the hazard lies.”
Monitoring the waves in real time
Forecasting tsunamis relies on a system of buoys placed across the ocean. These buoys, called DART (Deep-ocean Assessment and Reporting of Tsunamis), were developed by the Pacific Marine Environmental Laboratory in Washington.
Once a major earthquake is detected, the buoys measure sea-level changes and send the data to tsunami warning centres. These measurements help experts adjust warnings and advise on evacuations. This real-time information is critical, especially in the first few hours after a quake.
Despite the system’s importance, the laboratory responsible for DART is facing possible closure under the latest NOAA budget proposals.
Also Read: Watch as tsunami slams Russia's Kamchatka after 8.7 earthquake, first footage shows coast under water
Tsunami Do's and Don'ts: What you should know
Tsunami preparedness can save lives. Here’s what experts recommend at each stage.
Before a Tsunami
During a Tsunami warning
Where to seek shelter
If you live in a tsunami zone and can’t evacuate inland:
Russia earthquake most powerful on record
If confirmed, the 8.8 magnitude quake will rank among the ten strongest ever recorded. It would be tied for sixth place with the 2010 earthquake in Chile and the 1906 Ecuador quake.
The most powerful quake ever recorded was the 1960 Valdivia earthquake off Chile, which reached a magnitude of 9.5.
According to Michigan Technological University, earthquakes of 8.0 or higher are capable of widespread destruction and long-lasting consequences for affected communities.
As experts continue to monitor this event, coastal residents across the Pacific are being told to remain alert, follow official advice, and stay away from the water. The situation remains fluid.
Also Read: After the 8.7 magnitude earthquake in Russia: How far could the tsunami reach and who's most at risk?
In Hawaii, sirens and emergency messages were sent out as officials warned of potential flooding in coastal and low-lying areas. People were urged to evacuate to higher ground. Similar alerts rippled across the Pacific, reaching as far as Japan, Russia’s Kamchatka Peninsula, and even countries in Latin America and Southeast Asia.
Understanding tsunami warnings: What each alert means
The alerts have been issued in varying forms, depending on the region's risk level.
- Tsunami Warning: This is the highest level of emergency. A warning means a tsunami is either expected or already happening, with the likelihood of dangerous coastal flooding and strong currents. Residents are told to evacuate immediately.
- Tsunami Advisory: Indicates possible strong waves or currents. Flooding is possible but less likely to be widespread. Southern California is currently under this advisory, with waves expected to arrive during early morning hours.
- Tsunami Watch: This means a tsunami could form, but there is not enough data yet to confirm it. Most of the US West Coast is under a watch, with residents being advised to monitor updates closely.
Also Read: Powerful 8.7 earthquake off Kamchatka triggers tsunami alerts across Pacific coastlines
Hawaii, Japan and Russia already seeing impacts
The first tsunami waves have already reached Hawaii, and some may be as high as 10 feet above normal. Hawaii Governor Josh Green said residents should leave coastal zones "right away" as waves could "wrap around the islands".
Russia’s Kamchatka Peninsula was hit soon after the quake. In Severo-Kurilsk, multiple tsunami waves swept through, damaging infrastructure and even collapsing a kindergarten building. No injuries have been reported, but the district declared a state of emergency, according to TASS.
In Japan, tsunami waves have already landed along the eastern coast. These range from Hokkaido in the north to Honshu, including areas near Tokyo. So far, the waves have been relatively small, measuring around 60 centimetres. Still, over 1.9 million people across 21 prefectures are under evacuation advisories. Photos from Hokkaido show residents gathering on rooftops for safety.
Elsewhere, countries including Chile, Peru, Mexico, Panama, Taiwan, Indonesia and the Philippines have also issued tsunami alerts.
Also Read: Millions at risk: Inside the deadly 'Ring of Fire' that could trigger Earth’s next big disaster
Why tsunamis are so dangerous
Tsunami waves don’t behave like regular waves. They can look like fast-moving floods, surging inland over several minutes and then retreating, only to return again. These events can last for hours and hit without warning.
“A tsunami wave is extremely different than your typical ocean wave … it’s very much just like a torrent of floodwater coming at you at the coastline,” said Helen Janiszewski, assistant professor in the Department of Earth Sciences at the University of Hawaii at Mānoa, speaking to CNN.
She added, “Water moving quickly can really knock a person down quite easily. You don’t need a lot of it. And so it’s very, very dangerous.”
Janiszewski also warned that the impact depends heavily on local geography. "It’s not just the coastlines that are facing the direction the wave is coming from … there may actually be very complicated patterns as it arrives."
How tsunamis form and travel
Tsunamis are triggered when the ocean floor is suddenly displaced, often by an earthquake, volcanic eruption or landslide. That massive shift in water travels outward across the ocean at high speeds. In deep water, tsunami waves aren’t very noticeable. But when they approach the shore, they slow down and rise up dramatically.
According to the US National Weather Service, waves can appear as a fast-rising flood or a tall wall of water. In some cases, the water pulls back from the coast first, creating an eerie low tide effect before crashing back in.
Crucially, tsunamis are not single events. They often arrive as a series of waves that can flood, recede, and reflood land over hours. Large tsunamis can reach more than a mile inland.
Also Read: Tsunami warning today: Check countries and regions that are under high wave alert after 8.7 earthquake hits Russia's Kamchatka
What happens in Hawaii could indicate broader impact
Harold Tobin, a seismologist at the University of Washington, said the Hawaii response could offer a glimpse of what’s to come elsewhere. “What will be seen in Hawaii in the upcoming hours will be a test of what we might expect around the rest of the Pacific rim,” he told CNN.
He pointed out that some offshore quakes release energy outward into the ocean rather than back toward land. If this one follows that pattern, “then that will be a real win for everyone.”
“It could scale anywhere from really not any significant damage at all at long distances, to significant damage in areas that are right at coastal levels,” Tobin added.
“It’s important to emphasize people don’t need to panic if they’re far away from the shoreline or more than a few meters above sea level for most distant regions. But right at the shoreline in harbours, marinas, and coastal towns, that’s where the hazard lies.”
Monitoring the waves in real time
Forecasting tsunamis relies on a system of buoys placed across the ocean. These buoys, called DART (Deep-ocean Assessment and Reporting of Tsunamis), were developed by the Pacific Marine Environmental Laboratory in Washington.
Once a major earthquake is detected, the buoys measure sea-level changes and send the data to tsunami warning centres. These measurements help experts adjust warnings and advise on evacuations. This real-time information is critical, especially in the first few hours after a quake.
Despite the system’s importance, the laboratory responsible for DART is facing possible closure under the latest NOAA budget proposals.
Also Read: Watch as tsunami slams Russia's Kamchatka after 8.7 earthquake, first footage shows coast under water
Tsunami Do's and Don'ts: What you should know
Tsunami preparedness can save lives. Here’s what experts recommend at each stage.
Before a Tsunami
- Know whether you live in a tsunami-prone area.
- Learn your local evacuation routes.
- Pick a shelter on high ground or far inland.
- Set up a family communication plan.
- Keep emergency kits ready and practise evacuation drills.
During a Tsunami warning
- If there’s an earthquake, drop, cover and hold on.
- When the shaking stops, don’t wait. Move immediately to higher ground.
- Never go to the shore to watch the waves.
- Stay away from rivers, beaches and low-lying areas.
- If at sea, move to deeper water if advised.
Where to seek shelter
If you live in a tsunami zone and can’t evacuate inland:
- Go to a reinforced, multi-storey building like a hotel.
- Head to the upper floors.
- Never stay in small structures or low-lying homes.
- Offshore reefs may reduce the impact slightly, but they do not remove the danger.
- Wait for official updates before returning home.
- Stay away from flooded roads and unstable buildings.
- Avoid touching anything electrical in wet areas.
- Watch out for debris, mudflows and landslides.
- Use texts or social media to contact loved ones.
- Assist the elderly, disabled and children.
- Don’t enter disaster zones unless authorised.
- Take photos of any damage to support insurance claims.
- Don’t return to the coast until officials give the all clear.
- Don’t assume it's over after the first wave.
- Don’t try to swim or surf during tsunami activity.
- Don’t perform risky rescues yourself. Call professionals.
Russia earthquake most powerful on record
If confirmed, the 8.8 magnitude quake will rank among the ten strongest ever recorded. It would be tied for sixth place with the 2010 earthquake in Chile and the 1906 Ecuador quake.
The most powerful quake ever recorded was the 1960 Valdivia earthquake off Chile, which reached a magnitude of 9.5.
According to Michigan Technological University, earthquakes of 8.0 or higher are capable of widespread destruction and long-lasting consequences for affected communities.
As experts continue to monitor this event, coastal residents across the Pacific are being told to remain alert, follow official advice, and stay away from the water. The situation remains fluid.
Also Read: After the 8.7 magnitude earthquake in Russia: How far could the tsunami reach and who's most at risk?
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