--- title: New NASA Study Shows That Japan's Merging Tsunami Doubled the Destruction description: The tsunami that tore through northern Japan on March 11 was catastrophically strong. The waves—triggered by a 9.0 earthquake—swamped coastal towns, destroyed homes and offices... canonical: https://time.com/archive/7220061/tsunami-revelations-scientists-discover-that-the-japanese-tidal-wave-was-a-merged-tsunami-the-first-ever-observed/ author: TIME Staff article:opinion: false article:content_tier: free article:published_time: 2011-12-06T21:50:27.000Z article:modified_time: 2026-03-18T15:05:39.625Z article:section: Science og:title: New NASA Study Shows That Japan's Merging Tsunami Doubled the Destruction og:description: The tsunami that tore through northern Japan on March 11 was catastrophically strong. The waves—triggered by a 9.0 earthquake—swamped coastal towns, destroyed homes and offices... og:url: https://time.com/archive/7220061/tsunami-revelations-scientists-discover-that-the-japanese-tidal-wave-was-a-merged-tsunami-the-first-ever-observed/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt42b79ff0e2e22f38/6998b62093610c5b10c2dcd2/124655146.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: Tsunami og:type: article twitter:card: summary_large_image twitter:title: New NASA Study Shows That Japan's Merging Tsunami Doubled the Destruction twitter:description: The tsunami that tore through northern Japan on March 11 was catastrophically strong. The waves—triggered by a 9.0 earthquake—swamped coastal towns, destroyed homes and offices... twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt42b79ff0e2e22f38/6998b62093610c5b10c2dcd2/124655146.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  * [Science](/section/science/) # Tsunami Revelations: Scientists Discover that the Japanese Tidal Wave Was a 'Merged Tsunami' — the First Ever Observed by [TIME Staff](https://time.com/author/time-staff/) Dec 6, 2011 9:50 PM UTC  The tsunami's aftermath The tsunami's aftermathBloomberg / Getty Images by [TIME Staff](https://time.com/author/time-staff/) Dec 6, 2011 9:50 PM UTC The tsunami that tore through northern Japan on March 11 was catastrophically strong. The waves—triggered by a 9.0 earthquake—swamped coastal towns, destroyed homes and offices and led to the deaths of nearly 16,000 people. (For a chilling look at the devastation, [check out these photos](http://lightbox.time.com/2011/11/21/after-the-storm-kishin-shinoyama-documents-japan-post-tsunami/#1) by the Japanese photographer Kishin Shinoyama.) The tsunami also led to a [meltdown](http://ecocentric.blogs.time.com/2011/08/22/an-nuclear-exclusion-zones-arises-around-fukushima/) at the Fukushima Dai-ichi nuclear plant, resulting in the worst atomic accident since Chernobyl—with [long-term effects](http://ecocentric.blogs.time.com/2011/11/16/preliminary-reports-show-little-radiation-exposure-in-fukushima/) that are still up for debate. Obviously the sheer power of the quake helps explain why the tsunami was so devastating—but that’s not the only reason. Scientists from NASA and Ohio State University [now say](http://www.nasa.gov/home/hqnews/2011/dec/HQ%5F11-405%5FAGU%5FTsunami.html) that the waves were actually a “merged tsunami,” and that the phenomenon doubled the power of the disaster.more Satellites from NASA and European agencies show at least two wave fronts created by the quake—not just one as you might expect from a single quake. Those wave fronts merged to form a single, double-high wave out to sea. As it traveled towards land, ocean ridges and undersea mountains pushed the wave fronts together, keeping the tsunami stable even as it hurtled towards the coast. Said NASA research scientist Y. Tony Song at the American Geophysical Union meeting in San Francisco: --- > “” --- As scientific studies go, this one was pure luck—three satellites with the right kind of equipment all happened to be passing over the tsunami as it happened. The information should be able to help scientists better predict where, when and how severely tsunami waves will hit, enabling them to improve predictions and speed warnings when needed. That’s less of an issue for Japan, which already has by far the [best tsunami response system](http://www.emergencymgmt.com/disaster/Japan-Tsunami-Warning-System-031111.html) in the world, but poorer nations need all the help they can get. **MORE:** [**Needless Disease and Death in Somalia**](http://ecocentric.blogs.time.com/2011/08/16/needless-disease-and-death-in-somalia/) _Bryan Walsh is a senior writer at_ TIME_. Find him on Twitter at_ [_@bryanrwalsh_](http://twitter.com/#%21/bryanrwalsh)_. You can also continue the discussion on_ TIME’s[_Facebook page_](http://www.facebook.com/time) _and on Twitter at_ [_@TIME_](http://twitter.com/#%21/TIME) ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/archive/7220061/tsunami-revelations-scientists-discover-that-the-japanese-tidal-wave-was-a-merged-tsunami-the-first-ever-observed/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/archive/7220061/tsunami-revelations-scientists-discover-that-the-japanese-tidal-wave-was-a-merged-tsunami-the-first-ever-observed/"},"headline":"Tsunami Revelations: Scientists Discover that the Japanese Tidal Wave Was a 'Merged Tsunami' — the First Ever Observed","datePublished":"2011-12-06T21:50:27.000Z","dateModified":"2026-03-18T15:05:39.625Z","description":"The tsunami that tore through northern Japan on March 11 was catastrophically strong. 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