NASA / Jesse Allen, using data provided by Tony Song (NASA / JPL)

An image from an animation using satellite observations of the March 11 tsunami that shows how the waves of the tsunami were influenced by seafloor features. Wave peaks appear in red-brown, depressions in blue-green and ocean floor topography is outlined in gray.

By Elizabeth Howell
LiveScience

The global positioning system (GPS) — the same system that helps people navigate unfamiliar places — could also serve as an early-warning system for tsunamis, according to new research.

When a magnitude-9.0 earthquake struck Japan on March 11, 2011, coastal residents received an inaccurate estimate of the earthquake's magnitude before the waves hit and leveled thousands of buildings.

The area under alert was warned based on an estimated earthquake magnitude of 7.9 — 130 times less intense than the actual quake was — meaning fewer neighborhoods were evacuated in response to the perceived threat.

Researchers behind a new study have said that GPS systems along the coast could have given the residents a better warning. Sifting through the GPS data from stations along the coast and issuing a more accurate tsunami alert based on that data would have taken only three minutes, the study found. [7 Ways the Earth Changes in the Blink of an Eye]

Subduction zones and GPS
Most tsunamis occur when one tectonic plate slides underneath another and causes an earthquake. In the process, the top plate is forced upward, and this uplift of the seafloor pushes on the water above it, setting off the tsunami. How high the ground rose on the seafloor would influence wave heights up on the surface.

The coast also slightly rises or falls along with the ocean floor, making it possible to see these changes through coastal GPS stations. Therefore, areas near these so-called subduction zones can be mapped and measured using GPS to see how much the ground has shifted and in what way it has deformed.

Whereas traditional seismological stations are located some distance away from the source, GPS transmitters can be placed much closer, on the coastline, to where the tsunami occurred, buying valuable time for those looking to escape.

"To really get absolute values of slip, you would need to have stations at the seafloor," said Andreas Hoechner, a postdoctoral researcher at the GFZ German Research Centre for Geosciences in Potsdam.

"However, (the coastal GPS readings are) good enough to get good tsunami wave estimates."

A subduction quake makes several ocean waves: crest waves on top of the seafloor that rise, and trough waves on the seafloor that drop down. Additionally, independent research has recently showed that a shoreline's features also influence the severity of a tsunami's impact on land.

Reconstructing an alert
To reconstruct what a GPS alert would have looked like during the 2011 temblor, the scientists took information from the Japanese GPS Earth Observation Network (GEONET) the day before, the day of, and the day after the 2011 earthquake. The station is typically used for long-term changes to the ground, such as "relaxation processes" between earthquakes, but has not been applied yet for tsunami warnings, Hoechner said.

While Japan has about 1,200 of these stations, the researchers only used 50 of them in order to take less time to issue an alert. The exact number of stations does not matter in this scenario, Hoechner noted, as long as there are enough to note a rapidly changing height difference between the ground on the coast and the ground further inland.

GPS stations provide more accurate information about ground shifts than seismological stations do, as seismological stations are better suited for looking at the amount of ground shaking — rather than shifting — associated with an earthquake. Both systems are useful in their own ways and should be used together, Hoechner said.

In the case of Japan’s Tohoku earthquake, a tsunami warning issued just three minutes after the earthquake struck would have provided several minutes for people to scramble to safety. Tsunamis typically hit land about 20 to 30 minutes after they are generated, Hoechner said, depending on the distance between land and the earthquake's epicenter.

The challenge will be to actually use the GPS sensors for real events, not just for simulating past tsunamis. And the technique could be used not only in Japan, but also in Indonesia. After the devastating 2004 earthquake in that region, there were some GPS stations installed, but the researchers say more are needed to make accurate tsunami warnings.

The results appear in the latest edition of Natural Hazards and Earth System Sciences, an open-access journal of the European Geosciences Union.

Hoechner's team plans to extend its research to Chile, which was the site of a devastating tsunami in 2010.

Follow Elizabeth Howell @howellspace. Follow us @livescience, Facebook and Google+. Original article on LiveScience.com .

• 10 Tsunamis That Changed History
• Waves of Destruction: History's Biggest Tsunamis
• In Pictures: Japan Earthquake & Tsunami

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Department of Interior

The cherry trees around the National Mall of Washington, D.C., in peak bloom.

By Elizabeth Howell
LiveScience

The pink cherry blossoms that explode into bloom every spring in Washington, D.C., are famous around the country, flowering due to a courtesy gift from Japan more than a century ago. But one of the first attempts to send the flowers over to the capital didn't go so well.

A few seeds did make their way into the United States before the Japanese sent thousands in the 1900s. William S. Bigelow — an American physician living in Japan — and botanist Charles S. Sargent sent cherry trees to the Morris Arboretum in Philadelphia in the 1890s, for example, and the Imperial Botanic Garden in Tokyo added to the arboretum's collection in 1894.

In Washington, D.C., agriculture department official David Fairchild imported 100 Japanese cherry trees in 1906 to his own Maryland property to see how well they grew. [In Photos: Stages of Cherry Blossom Blooms]

Three years later, the Japanese sent more than 2,000 young trees to be planted near the Potomac River as a symbol of the growing friendship between the two nations. The trees were unfortunately infested with roundworms and insects. President William Howard Taft, acting on advice from agriculture officials, ordered the trees burned and destroyed.

Seeking to avoid a rift, the U.S. secretary of State swiftly sent his regrets to the ambassador from Japan. The island nation renewed its vow to send seeds over, shipping more than 3,000 in 1912. Those trees were healthy and were planted as planned.

Expanding across the United States
The Washington cherry trees have attracted their share of both positive and negative attention over the years. The first cherry blossom festival there took place in 1935, but in 1941, four cherry trees were cut down shortly after the Japanese invaded Pearl Harbor. Officials began referring to them as "Oriental" trees to try to prevent such incidents in the future.

Meanwhile, cherry trees began sprouting in other U.S. locations.

The Brooklyn Botanic Garden planted its "cherry walk" in 1921.

A realtor in Macon, Ga., decided to expand the number of cherry trees in his hometown after visiting Washington, D.C., in 1952. He was "awed by the tree's unique beauty," according to the city's cherry blossom festival website.

In honor of its 175th anniversary, Ohio University received 175 trees from Chubu University (a sister location in Japan) in 1979. Chubu renewed the gift in 2004 for Ohio's bicentennial.

Cherry blossom ("sakura" in Japanese) festivals are now held every spring in these cities, as well as other locations in the United States. The trees stand as not only a symbol of friendship, but also as a glimmer of the fragility of spring.

"Sakura is a symbol of ... continuation of resilient life and the fragile and momentary aspect of natural beauty because sakura flowers do not stand well against harsh natural elements like rain and wind," stated a 2008 article published by Ohio University.

Follow Elizabeth Howell @howellspace, or OurAmazingPlanet @OAPlanet, Facebook and Google+.Original article at LiveScience's OurAmazingPlanet.

• 6 Signs that Spring Has Sprung
• What's the Cultural Significance of Cherry Blossoms?
• Hold Your Nose: 7 Foul Flowers

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Credit: National Oceanic and Atmospheric Administration (NOAA)Credit: National Oceanic and Atmospheric Administration

The magnitude-9.0 earthquake that struck Japan triggered tsunamis across the region. Here, results from a computer model run by the Center for Tsunami Research at the NOAA Pacific Marine Environmental Laboratory show the expected wave heights of the tsunami as it travels across the Pacific basin.

By Becky Oskin
LiveScience

Predicting flooding from tsunamis saves lives. After the Tohoku earthquake two years ago, alerts issued in advance of the monster waves saved thousands of people in Japan and other countries circling the Pacific Ocean.

But for many in Japan, the forecasts failed. Models could not predict how far inland the tsunami would rush, leading to thousands of deaths.

A new study suggests the devastating effects were heavily dependent on more than just the enormous size of the magnitude-9.0 earthquake that triggered the tsunami. The distance of the coast from the point where the earthquake ruptured also played a role. At just the right spacing from a coastline, a tsunami wave can focus its energy at the coast, sweeping farther inland than current models predict, researchers found.

"The effect of focusing that we have described can happen at a coastline directly in front of the (earthquake) source, where historically (the) most fatalities occur during tsunamis," said Vasily Titov, director of the National Oceanic and Atmospheric Administration's Center for Tsunami Research in Seattle and a study co-author. [Waves of Destruction: History's Biggest Tsunamis]

The results could improve computer models that predict tsunami flooding, the researchers said. The findings appear in the Feb. 27 issue of the journal Proceedings of the Royal Society A.

"We are still trying to understand the implications," said Costas Synolakis, a tsunami expert at the University of Southern California in Los Angeles and another co-author of the study. "But it is clear that our findings will make it easier to identify locales that are tsunami magnets, and thus help save lives in future events," he said in a statement.

Subduction zones and tsunamis
The Tohoku earthquake struck on a subduction zone, an area at which two of Earth's tectonic plates crash together and one slides beneath the other. Notorious tsunami generators, earthquakes in these areas lift the seafloor on one side of the subduction zone and drop it down on the other side. Such elevation changes give the water above a giant push, creating a tsunami.

Each subduction zone quake generates multiple waves: a crest wave, above the uplifted seafloor, and a trough wave, from the dropped seafloor. The trough side starts with a big dip, or trough, while the crest side leads with a swell, or crest.

So a tsunami is actually a series of waves. Both the crest and trough wave sides propagate in both directions; the crest side sends waves both out into the open ocean and towards the shore, as does the trough side.

Subduction zones are always oriented so the trough side of the tsunami is closer to, and thus the first to advance toward, the nearest shoreline, Costas noted. The international research team created a computer model simulating a subduction zone tsunami. The model showed that waves from the crest side decrease in height continuously as they travel through the ocean, then grow in height near the shore, an effect called shoaling.

But trough-side waves vary in height as they travel through the ocean, the study found. At a certain distance from the earthquake source, called the focusing point, one wave from the crest side overtakes two waves from the trough side. The combined wave energy makes the tsunami even taller, though it quickly dissipates.

"The trough-wave side first decreases, then increases in height, then decreases again," Costas told OurAmazingPlanet.

The Goldilocks effect
"This means the distance between the earthquake zone and the shoreline is extremely important," Costas said. Sometimes, a trough-wave tsunami will come onshore right at its highest peak, driving water farther inland than expected.

But if the distance between a tsunami-generating earthquake and a shoreline is very short, focusing does not have time to occur. If the distance is long, focusing takes place far from the shore. If the distance between the subduction zone and the nearby land is just right, then focusing amplifies the wave height, making it bigger.

The team observed this effect in their model of the 2011 Tohoku earthquake. The same effect occurred in Central Java, which was struck by a tsunami in 2006, and in Papua New Guinea, where 2,200 people died in a 1998 tsunami.

Email Becky Oskin or follow her @beckyoskin. Follow us @OAPlanet, Facebook or Google+. Original article on LiveScience's OurAmazingPlanet.

• Seafloor Focused Japan Tsunami Waves
• 7 Ways the Earth Changes in the Blink of an Eye
• In Pictures: Japan Earthquake & Tsunami

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Kyodo via Reuters

A Japanese H-2A rocket carrying an information-gathering radar satellite blasts off from its island launch pad at Tanegashima Space Center.

TOKYO — Japan launched two intelligence satellites into orbit on Sunday amid growing concerns that North Korea is planning to test more rockets of its own and possibly conduct a nuclear test.

Officials say the launch Sunday of the domestically produced H2-A rocket went smoothly, and the satellites — an operational radar satellite and an experimental optical probe — appear to have reached orbit.

Japan began its intelligence satellite program after North Korea fired a long-range missile over Japan's main island in 1998. North Korea conducted a launch last month that it says carried a satellite into orbit but has been condemned by the United States and others as a cover for its development of missile technology.

The latest Japanese launch was in the planning stages long before the current increase in tensions with North Korea, but underscores Japan's longstanding wariness of its isolated neighbor's abilities and intentions.

The radar satellite, which can provide intelligence through cloud cover and at night, is intended to augment a network of several probes that Japan already has in orbit. The optical probe will be used to test future technology and improvements that would allow Japan to strengthen its surveillance capabilities.

Japan still relies on the United States for much of its intelligence.

Its optical satellites are believed to be about as good as commercial satellites, meaning they are able to detect objects of about 40 centimeters (16 inches) in size from their orbits. With the additional radar satellite, Japan hopes to be able to glean intelligence on any specified location once a day.

Japan, which hosts about 50,000 U.S. troops, is especially concerned about North Korea because its main islands are already within range of the North's missiles. Along with developing its own network of spy satellites, Japan has cooperated with Washington in establishing an elaborate missile defense shield.

North Korea's powerful National Defense Commission declared last week that the country would carry out a nuclear test and launch more rockets in defiance of the U.N. Security Council's announcement that it would punish Pyongyang for its long-range rocket test in December with more sanctions, calling it a violation of a ban on nuclear and missile activity.

North Korea's state news agency said on Sunday that leader Kim Jong Un vowed at a meeting of top security and foreign officials to take "substantial and high-profile important state measures."

Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Hideki Takami, Fisheries Research Agency Japan

Underwater photographs of a rocky shore area at Tomarihama in northeastern Japan. On the left, sea urchins (Strongylocentrotus nudus) before the tsunami on Nov. 11, 2010. On the right, the area after the event (on June 8, 2011), with large rocks cracked and turned over on the sea floor. In consequence, bare rock was exposed and urchins were not observed.

By Charles Choi, Contributor, OurAmazingPlanet

The devastating earthquake that ravaged Japan in 2011 may have also wreaked havoc on vital fisheries, researchers say.

The magnitude 9.0 Tohoku-Oki temblor in 2011 was the most powerful earthquake to hit Japan in recorded history, and set off a tsunami that lay waste to the country's northeastern coast, claiming the lives of nearly 19,000 people.

Past studies have analyzed the effects of tsunamis on marine ecosystems, for example investigating the effects the 2004 Indian Ocean tsunami had on coral reefs, seagrass beds and mangrove forests. A recent study also showed how the tsunami affected the seafloor by leaving behind huge, underwater dunes. However, until now, scientists had not looked into the effects of a major tsunami on fisheries, one of Japan's most important industries.

Since 2008, researchers had regularly surveyed fishery resources at the port of Tomarihama, the coastal area closest to the epicenter of the quake.To see what effects the tsunami had, scientists took a fisherman's boat to analyze this site via scuba diving three months after the catastrophe. Trees and structures up to 50 feet (15 meters) high on the area's coast were almost entirely destroyed by the disaster, suggesting the tsunami reached at least that height there. [ In Pictures: Japan Earthquake & Tsunami ]

"More than 90 percent of the boats around the survey point were swept away or destroyed by the tsunami, so it was difficult to rent a boat after the disaster," said researcher Hideki Takami, a marine biologist at the Tohoku National Fisheries Research Institute in Japan.

The scientists focused their survey on two types of marine life, abalone (Haliotis discus hannai) and sea urchin (Strongylocentrotus nudus). Both are valuable fisheries resources in Japan, and since they are common and abundant grazers there, both may exert strong influences on the marine ecosystems where they live.

The researchers found that levels of adult abalone dropped by more than half after the tsunami. In addition, "juvenile abalone and sea urchins largely decreased, to 14 and 5 percent of the densities just before the disaster, respectively," Takami told OurAmazingPlanet.

Underwater visibility at the site was much lower than it was before the earthquake due to sediment in the ocean, even three months after the tsunami. The researchers suggest the great turbulence the tsunami caused washed away many of the animals in the ecosystem.

The researchers do note these findings are based on surveys conducted at just one site, "so the overall picture of effects of the earthquake and tsunami event on rocky shore ecosystems remains largely unknown," Takami said. Still, given the drop in juvenile abalone levels, "since the age at first capture of abalone is at four to five years old, "the future commercial catch may considerably decrease for at least four to five years after the event," he said.

Future research should continuously monitor the ocean ecosystems "to avoid collapse of these ecologically and economically important resources," Takami said.

Takami and his colleagues Nam-il Won and Tomohiko Kawamura will detail their findings in a future issue of the journal Fisheries Oceanography.

• 7 Craziest Ways Japan's Earthquake Affected Earth
• Waves of Destruction: History's Biggest Tsunamis
• 7 Ways the Earth Changes in the Blink of an Eye

© 2012 OurAmazingPlanet. All rights reserved. More from OurAmazingPlanet.

The world's first moving images of a giant squid living in its natural habitat have been captured by a team of scientists more than half a mile below the surface of the Pacific Ocean.

The ghostly pictures of the 10-foot-long giant squid were recorded from a state-of–the-art submersible carrying a three-person team of Japanese zoologist Tsunemi Kubodera, a camera operator and the submersible’s pilot, who made around 100 dives during an expedition last summer.

Although small by giant squid standards – the largest ever caught measured 59 feet – it was the first time a live giant squid had been caught on video deep in the ocean.

Kubodera, from Japan's National Museum of Nature and Science, credited the success to the submersible’s silence and hi-tech lighting.

"A giant squid would never appear before a pool of light, that possibility is extremely slim", he told NBC News. "That's why we had to use lights that they wouldn't be able to detect. In fact, they're lights even humans wouldn't be able to see either."

“If you try to approach making a lot of noise, using bright lights, then the squid won't come anywhere near you," he added. “So we sat there in the pitch black, using a near-infrared light invisible even to the human eye, waiting for the giant to approach.''

'It was stunning'
On one dive in July 2012, near the Ogasawara islands, 620 miles south of Tokyo, they finally had their close encounter more than 2,000 feet down and followed the creature even deeper.

“This was the first time for me to see with my own eyes a giant squid swimming,'' Kubodera said. “It was stunning. I couldn't have dreamt that it would be so beautiful. It was such a wonderful creature.”

NHK/NEP/Discovery Channel via Reuters

A giant squid is seen in this video still talken near the Ogasawara Islands in July 2012.

The squid was missing its characteristic two longest tentacles – and scientists don’t know why. Marine biologists said if that pair of tentacles had been intact, the creature would probably have measured up to 23 feet long.

Kubodera’s deep-sea expedition was the culmination of a 10-year project by Japanese broadcaster NHK to capture pictures of the mysterious creature in its habitat. An  ultra-sensitive high-definition camera was developed to operate at the ocean depths, using special light that was invisible to the sensitive eyes of the giant squid.

NHK will air its video footage in Japan in a prime-time documentary entitled "Legends of the Deep: Giant Squid" on Jan. 13. It will also be shown on the Discovery Channel on Jan.  27.

Reuters contributed to this report.

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