Latest news with #DavidTappin
Metro
31-07-2025
- Science
- Metro
I've studied tsunamis for 25 years - here are the warning signs one is coming
One of the most powerful earthquakes ever recorded triggered huge tsunami waves across the Pacific Ocean. Some as high as four metres were observed after the 8.8-magnitude tremor struck off the city of Petropavlovsk, on Russia's remote Kamchatka Peninsula on Wednesday. Safety alerts have been downgraded but still remain in parts of Japan, the Pacific and over 3,000 miles (5,000 kilometres) away in Chile. Professor David Tappin, a marine geologist at the British Geological Survey, woke up to over 50 emails from global tsunami warning systems after the quake. The expert, who has studied tsunamis for over 25 years, explained to Metro how tsunamis form from the seabed and how they travel so far across the globe. Tsunami's are caused by large scale disturbances on the seafloor. Most commonly, and in the case of yesterday's tsunami warnings, it is earthquakes that trigger the massive waves. 'Earthquakes are the most hazardous tsunami mechanism,' Prof Tappin explained. Violent earthquakes occur due to a build-up of pressure between the tectonic plates that make up the Earth's crust. The crust 'plunges down into the mantle' Prof Tappin laid out what happened yesterday: 'Off Kamchatka, the Pacific plate is moving westwards towards Russia and it's plunging down into the mantle 'Due to the pressure, there was a massive movement yesterday evening that caused an earthquake.' The tsunami expert said that when the seabed moves during an earthquake, that same movement happens to the ocean above. So, for example, if the sea bed ruptured by 10 meters, then the waves generated on the sea surface would be 10 metres high. Prof Tappin said: 'The sea surface reflects that vertical movement of the sea bed. 'So during an earthquake, the sea surface collapses and that generates a tsunami.' One of the most infamous warning signs of a deadly tsunami is when the tide pulls away from the shoreline. Beachgoers may be tempted to investigate, or pick up dead fish, but in reality a massive tsunami wave could be just minutes away. But the tide does not always recede before the giant waves strike, as Prof Tappin explained. When the tectonic plates move, the seabed either moves up or down. When there is 'downward movement' that is when a 'trough' can be created in the sea. 'As the trough approaches the coastline, that's what causes the wave to recede,' Prof Tappin said. But the opposite can also happen, where the seabed moves upwards due to the build-up of pressure, triggering a 'positive wave'. This leads to an initial, particularly high, wave that hits the coastline. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video It took just hours for tsunami waves as high as 4 metres to strike Japan after the earthquake off Kamchatka. Yet tsunami waves then smashed into the coastlines of North and South America hours later, with many coastal communities told to stay cautious over the next 24 hours. However as these devastating waves travel over the ocean, they are hardly noticeable. Prof Tappin explains that is because the distance between each wave, called the wavelength, is actually hundreds of kilometres before they reach the coast. At this stage, the ocean is nearly two miles in depth and there is hardly any friction stopping the waves' movement. This lack of friction is why the tsunami that hit the US overnight were still powerful. The Galapagos Islands and parts of the US saw 4ft waves, as tall as those faced by many in Japan. Those waves, which appear 'benign' in the deep ocean, only become tall and frightening when it gets close to land. Prof Tappin said: 'When it approaches the opposite shore, the water depths approach and there is a frictional effects which leads to the build up of the tsunami. 'The wavelength reduces but the height of the wave increases.' The world's first tsunami warning system was set up in 1946 after a devastating disaster that year. Headquartered in Honolulu, Prof Tappin explained how it works: 'It is composed of around 100 seismometers, which measure earthquakes. 'They are working 24/7, and if there is an earthquake larger than magnitude seven, then the warning centre identifies this.' All eyes then turn to tide gauges, which measure the height of an ocean, based around the Pacific 'If there is an abnormality in the wave height after a magnitude seven quake then the warning bell rings. 'The center will then send out a warning to local organizations who are responsible for deciding when and how to evacuate people.' After the Kamchatka Peninsula earthquake, warnings or alerts about tsunami waves were issued in more than a dozen countries, including in Russia, Japan, Taiwan, the Philippines, Mexico and California. More Trending The difference a warning system can make can be huge. The tsunami in Japan in 2011 saw 15 metre waves, but because of the pacific warning system only 18,000 people died. Whereas in the Indian Ocean tsunami in 2004 there was no warning system and 230,000 people lost their lives. After 2004 a warning system was also established for the Indian Ocean and Mediterranean. Get in touch with our news team by emailing us at webnews@ For more stories like this, check our news page. MORE: Tsunami warnings still in place after 8.8 magnitude Russian earthquake MORE: This country will be underwater by 2050 — and people are entering a bleak competition to escape MORE: Whales eerily become beached hours before earthquake – do they predict them?
NBC News
30-07-2025
- Science
- NBC News
Massive earthquake off Russia's east coast is one of the most powerful ever recorded
The earthquake that struck Russia's eastern Kamchatka region and triggered tsunami warnings across the Pacific is among the most powerful temblors to have been recorded in modern history. The U.S. Geological Survey (USGS) may revise the magnitude of the earthquake, but if it remains at 8.8, this quake would be tied with the sixth strongest ever, which struck central Chile in 2010, killing more than 500 people and destroying over 370,000 homes. Russian authorities have called the latest quake a 'remarkable event.' It struck at a depth of an estimated 13 miles, about 74 miles off the coast of Petropavlovsk-Kamchatsky, the regional capital on the Kamchatka Peninsula, with a population of 180,000. Despite its strength, early reports indicate that there have been no deaths or significant damage from the event and that recorded tsunami waves reached a maximum of 9.8 to 13.1 feet in Russia, 4.9 feet in Japan and 5.7 feet in Hawaii. David Tappin, principal researcher at the British Geological Survey, said he's surprised by this. 'When I first saw it was 8.8, I must admit, I thought, 'Oh, we're going back to maybe Japan,'' he said, referring to the 2011 earthquake that triggered a huge tsunami, killing more than 20,000 people and causing a meltdown at the Fukushima Daiichi nuclear power plant. Now referred to as the 'Great Tohoku Earthquake,' it had a magnitude of 9.1, the fourth most powerful ever recorded. The waves from that tsunami reached as high as 130 feet, according to the National Oceanic and Atmospheric Administration, hitting the coast at a height of about 50 feet. 'At the present time, it seems quite anomalous. 8.8 magnitude generating a 4-meter tsunami seems very unusual but … the information on the tsunami impact is still quite limited,' Tappin said, adding that he would have expected a tsunami of at least 10 meters, or about 33 feet. He said the relatively insignificant damage reported so far could be due to the remoteness of the epicenter and the effectiveness of the warning systems. 'It seems to me that the warning system kicked in, and warnings were given in Japan initially, Hawaii and off the West Coast of the U.S. So it just demonstrates the importance of having these warning systems,' Tappin said. 'In this instance, perhaps the tsunami wasn't large, but it saves people's lives.' The fifth-strongest earthquake ever recorded, a 9.0 tremor, also hit the Kamchatka region in 1952. Its epicenter was less than 19 miles from this one. In that disaster, the waves reached up to 50 feet and killed at least 1,790 people, with some historians putting the death toll as high as 8,000, according to the Russian Military Historical Society. The region has experienced nearly 700 earthquakes with magnitudes over 5.0 since 1990, according to the USGS. The most powerful earthquake ever recorded was the magnitude-9.5 'Valdivia' or 'Great Chilean' earthquake, which hit central Chile in 1960, killing more than 1,600 people and leaving 2 million homeless. One of the world's most deadly earthquakes was the third most powerful ever recorded, which struck off the coast of Sumatra, Indonesia, on Boxing Day in 2004. The 9.1-magnitude quake triggered massive tsunamis reaching up to 100 feet and killed an estimated 280,000 people.
