Tag Archives: tsunami

A researcher analyzes pieces of pottery found near Banda Aceh, Indonesia. Credit: Patrick Daly.

Ceramics Trace a 14th Century Indonesian Tsunami

Archaeological evidence suggests that communities on the northern coast of Sumatra devastated by a tsunami roughly 600 years ago opted to rebuild in the same area, a process repeated in 2004.

A researcher analyzes pieces of pottery found near Banda Aceh, Indonesia. Credit: Patrick Daly.

A researcher analyzes pieces of pottery found near Banda Aceh, Indonesia. Credit: Patrick Daly.

The first waves rolled ashore in Banda Aceh, on the northern tip of Sumatra, barely 20 minutes after a magnitude 9.1 megathrust earthquake struck the Indian Ocean on 26 December 2004. After the last of a series of tsunamis slammed the community, the death toll in Indonesia exceeded 150,000.

Following the so-called Boxing Day tsunamis, survivors opted to rebuild their lives within the inundation zone rather than abandon the exposed coastline. Now, scientists have used archaeological evidence from the coast of Sumatra dating back to the 14th century to show that returning to a tsunami-devastated region has a long historical precedent. Their results were published last month in the Proceedings of the National Academy of Sciences of the United States of America.

No Shortage of Tsunamis

Patrick Daly, an archaeologist at Nanyang Technological University in Singapore and lead author of the new study, works just across the Strait of Malacca from the Indonesian island of Sumatra. He remembers visiting Banda Aceh, the capital of Indonesia’s Aceh Province and the site of some of the worst destruction from the 2004 Indian Ocean tsunami, in 2006.

Seeing the extensive wreckage firsthand got Daly thinking about how frequently tsunamis strike the region. “Have there been other societies that have dealt with similar things?” he remembers wondering.

The answer, Daly and his colleagues soon realized, was a definitive yes. In a study published in 2017, a team of researchers, including Daly, found evidence that 11 tsunamis had struck near Banda Aceh between 7,400 and 2,900 years ago. Other research teams analyzing sand deposits and growth patterns of corals suggested that tsunamis also struck the area more recently, in about 1394 and 1450. Daly and his collaborators set about looking for archaeological evidence from the 14th and 15th centuries to determine the impacts of these more recent tsunamis.

Sherds, Sherds Everywhere

The scientists examined a 40-kilometer section of the Sumatran coastline near Banda Aceh.

Working with a team of over 60 Acehnese individuals recruited through the International Centre for Aceh and Indian Ocean Studies, they collected more than 30,000 pieces of broken ceramic pottery (sherds). The team found the roughly 5- to 15-centimeter fragments, which had been exposed by erosion and the 2004 tsunamis, both on the ground and in beach-facing cliff faces. These pieces were trade ceramics, the researchers concluded, and were originally made in places as far-flung as China, India, Syria, Thailand, and Vietnam. They were “the type of stuff you’d find in museums of Asian art,” said Daly.

On the basis of the style and design of the pottery, the team grouped the sherds into five time periods ranging from pre-1400 to 1650–1800.

The researchers found that the ceramics tended to be clustered in sites, implying geographically distinct settlements engaged in trade. These settlements, 10 in total, likely corresponded to modest-sized fishing villages, the researchers concluded. Nine were located within the inundation zone of the 2004 tsunami, and the 10th was situated on a promontory roughly 60 meters above sea level.

Trading from a Hill

Mining through their extensive database of age-dated, geographically tagged sherds, Daly and his collaborators noted a curious result: The settlements contained over 3,800 sherds confidently dated to before 1400 but only 70 sherds confidently dated to 1400–1450.

This fiftyfold decrease was consistent with the occurrence of a tsunami in 1394 that temporarily wiped out trading, the team reasoned.

“A powerful tsunami in the middle ages around 1394, analogous with the 2004 event, does indeed give the best fit with the detailed archaeological data set, ” Hendrik J. Bruins, a geoarchaeologist at Ben-Gurion University of the Negev, Israel, who was not involved in the research, told Eos.

Further support for this hypothesis soon emerged: 56 of the 70 sherds dated to 1400–1450 were found at the 10th settlement, the one atop the promontory and therefore presumably above the reach of tsunami waves. “Cluster 10 clearly retained connections to its international trading partners over this period,” the researchers wrote.

Daly and his colleagues went on to find that the hilltop settlement was abandoned by roughly 1550. Around the same time, trade started to increase at the low-lying villages, sites that would have likely been destroyed by the 1394 tsunami.  Researchers don’t know what caused the shift in trading patterns, but Daly and his team hypothesize that outsiders may have been moving into the low-lying settlements.

“You’re getting new groups of people taking advantage of the depopulation to set up a new trading infrastructure,” said Daly.

The area around Banda Aceh is an ideal meeting place for traders, he said, because it’s situated near the Bay of Bengal and therefore readily accessible from India, China, and Southeast Asia.

Accepting Risk

The results in the new paper show that there’s a long history of people moving back into tsunami-prone regions after a disaster, said Daly. That’s partially because there are “massive social and economic consequences to relocating people.” Humans are also remarkably good at accepting a certain degree of risk, particularly for rare events like tsunamis, Daly said.

The Acehnese coast will surely be hit by another tsunami in the future, said Daly, who notes that only time will tell if people will once again rebuild in such a disaster-prone area. He and his team are continuing to piece together the tsunami record in the area, particularly focusing on the last 2,000 years, he said. “We’re telling this big archaeological, environmental story.”

Story by Katherine Kornei, freelance science journalist. This article first appeared on EOS, and was republished here under a CC BY-NC-ND 3.0 licence.

Some 600 years ago, a massive tsunami struck Sumatra — in the same place as the 2004 tsunami

In 2004, an underwater earthquake with a magnitude of 9.1–9.3 Mw struck off the northern coast of Sumatra, in Indonesia. As if that wasn’t enough, the earthquake triggered a huge tsunami with waves as high as 30 meters (100 feet). This disaster killed over 280,000 people and displaced millions; 160,000 people were killed in the province of Aceh alone.

Now, researchers have found evidence of another earthquake hitting the same area 600 years ago.

Project staff member analyzing a broken medieval carved stone grave marker from the previous tsunami in Sumatra. Credit: Patrick Daly.

In the aftermath of 2004, mourning and rebuilding took over Indonesia. The tsunami also revealed something rather bizarre: Muslim gravestones, straight in the path of the tsunami. Geologists analyzing the area found evidence that another tsunami struck the area in 1394. Now, a team of researchers went back to the area, looking for evidence of other people living in the area before and after the medieval tsunami — and what they found is harrowing.

There were 10 settlements in the area, 9 of which were completely destroyed by the 1394 tsunami. The last one survived because it was placed on a hilltop high enough to escape the waves. Researchers studied the ceramics and other artifacts they found from the site, finding that the communities were established in the 11th and 12th centuries, coming from places as far away as China and Syria.

Even the 10th community decliner rapidly, presumably due to lack of trade partners or a larger community. While this can’t be estimated directly, the shock of seeing everyone around you being killed by a giant wave must have also had a dramatic impact on local inhabitants.

Project staff recording carved Muslim gravestone that was displaced by the 2004 Indian Ocean tsunami. Credit: Patrick Daly.

Soon enough though, other Muslim traders moved in, trying to rebuild the fallen communities, ultimately establishing an Islamic kingdom known as the Aceh Sultanate — notable for being ruled by a series of sultanas (female sultans). As time passed, the power of the Aceh Sultanate gradually faded away, although, in one form or another, it survived until 1903. It was the tsunami that paved the way for all of this, creating empty and prime locations for traders.

As generations passed, people forgot about the tsunami — by 2004, it was completely forgotten, paving the way for a new tragedy.

Indonesia isn’t the only place where historical tsunamis have had a huge impact.

Japan’s northern coastline is dotted with “tsunami stones” warning the population where not to build homes. “Remember the calamity of the great tsunamis. Do not build any homes below this point,” one such stone from 1896 reads. Many of these stones’ warnings were disregarded or forgotten as coastal towns boomed, but in some places, residents still heed the warning. Japan also experienced a devastating earthquake and tsunami in 2011.

 

Contour maps depict changes in gravity gradient immediately before the earthquake hits. Credit: Kimura Masaya.

New gravity earthquake detection method might buy more time for early warnings

Scientists from Japan, one of the most seismically active regions of the globe, claim that a new earthquake detection method based on gravity could provide an earlier warning than traditional methods.

Contour maps depict changes in gravity gradient immediately before the earthquake hits. Credit: Kimura Masaya.

Contour maps depict changes in gravity gradient immediately before the earthquake hits. Credit: Kimura Masaya.

In 2011, a magnitude-9 earthquake hit eastern Japan, along a subduction zone where two of Earth’s tectonic plates collide. The tremor came as a one-two punch, generating a huge tsunami in the process which led to the meltdown of the Fukushima Daiichi nuclear power plant. The effects of the powerful quake were devastating, with more than 120,000 buildings left in rubble and $235 billion-worth of incurred damage.

Japan handled the onslaught bravely and admirably. Thanks to its sophisticated network of sensors, Tokyo residents were given a minute warning via texted alerts on their cell phones before the city was hit by strong shaking. These sensors also recorded a wealth of data that is still keeping researchers busy with work that might lead to improved earthquake detection.

Exactly 8 years after the Tohoku earthquake, a team of researchers from the University of Tokyo’s Earthquake Research Institute (ERI) used some of this data to argue that a new detection method based on gravimeters could theoretically detect earthquakes earlier than seismometers.

Gravimeters are sensitive devices for measuring variations in the Earth’s gravitational field. They’re typically employed by industries to prospect subterranean deposits of valuable natural resources, including petroleum and minerals, but also by geodesists who study the shape of the earth and its gravitational field.

When an earthquake occurs at a point along the edge of a tectonic plate, it generates seismic waves that radiate outward at up to 8 kilometers per second. These waves transmit energy through the earth, thereby altering the density of the subsurface material they pass through. Denser material has a slightly greater gravitational attraction than less dense material, and since gravity waves propagate at the speed of light, it’s possible to measure these changes in density before the arrival of a seismic wave.

The Japanese researchers combined gravimetry and seismic data, which they fed into a complex signal analysis model. The results scored 7-sigma accuracy, meaning that there’s only a one-in-a-trillion chance that they are incorrect.

“This is the first time anyone has shown definitive earthquake signals with such a method. Others have investigated the idea, yet not found reliable signals,” ERI postgraduate Masaya Kimura said in a statement. “Our approach is unique as we examined a broader range of sensors active during the 2011 earthquake. And we used special processing methods to isolate quiet gravitational signals from the noisy data.”

TOBA prototype. Credit: Ando Masaki.

TOBA prototype. Credit: Ando Masaki.

At the moment, the researchers are working on a new kind of gravimeter called the torsion bar antenna (TOBA), which aims to be the first instrument specifically designed to detect earthquakes by gravity. A network of such devices could theoretically warn people 10 seconds before the first seismic waves arrive from an epicenter 100 km away. These precious extra seconds could mean the difference between life and death in many situations.

“SGs and seismometers are not ideal as the sensors within them move together with the instrument, which almost cancels subtle signals from earthquakes,” explained ERI Associate Professor Nobuki Kame. “This is known as an Einstein’s elevator, or the equivalence principle. However, the TOBA will overcome this problem. It senses changes in gravity gradient despite motion. It was originally designed to detect gravitational waves from the big bang, like earthquakes in space, but our purpose is more down-to-earth.”

The findings appeared in the journal Earth, Planets and Space.

Japanese tsunami sent millions of creatures to the US West Coast

Much like mankind, the animal kingdom also has refugees. When their habitats became uninhabitable following the Japanese tsunami of 2011, they fleed as far as they could, even if it meant treacherous journeys on makeshift rats.

These are marine sea slugs from a Japanese vessel in Iwate Prefecture which washed ashore in Oregon in April 2015. Credits: John Chapman.

In 2011, a dramatic 9.1 earthquake struck off the coast of Japan, creating a tsunami which left even more destruction in its wake. Men and animals alike ran, scrambling to escape the ungodly event. Researchers knew that many species escaped as far as North America, and in 2015, they were still hitching rides away from Japan. Now, for the first time, researchers detected entire communities of coastal species crossing the ocean by floating on makeshift rafts. Marine biologists from the Smithsonian Environmental Research Center in Maryland and Oregon State University report that even today, species are still arriving.

When coastal ecosystems are affected by storms or tsunamis, organisms can be rafted across oceans on floating debris, researchers write. However, such events are rarely observed, still less quantified. In this sense, the tsunami generated by the earthquake offered a good research opportunity. It turned out, as co-author John Chapman said, one of the biggest, unplanned natural experiments in marine biology.

Some 300 species arrived in America between June 2012 and February 2017, including some which have never before been seen on the continent. It’s not uncommon for species to drift from one place to another, but the sheer length of this migration is impressive.

“I didn’t think that most of these coastal organisms could survive at sea for long periods of time,” Smithsonian marine biologist Greg Ruiz, a study co-author, said in a statement. “But in many ways they just haven’t had much opportunity in the past. Now, plastic can combine with tsunami and storm events to create that opportunity on a large scale.”

The diversity of the species was also shocking. It’s not like a few species with the same profile escaped, there were all sorts of varied creatures.

“The diversity was somewhat jaw-dropping,” said James Carlton, a marine sciences professor at Williams College, in Williamstown, Massachusetts. “Molluscs, sea anemones, corals, crabs, just a wide variety of species, really a cross-section of Japanese fauna.”

A vessel carried by the Japanese tsunami washed ashore in Oregon, coated in gooseneck barnacles that colonized the boat as it floated across the North Pacific. Image credits: John Chapman.

None of the 289 species that arrived on debris were expected to survive the long journey, especially because the open ocean is considered to be a harsher environment for creatures used to the milder conditions of the coast. Researchers believe that their survival was facilitated by the slower speed of the drifting debris. This slow speed allowed the creatures to gradually adjust to their new conditions. Ironically, ocean pollution might have made it easier for them to survive. Researchers found many species floating on fiberglass or other plastic materials that do not decompose and could easily survive for years and years in the ocean. However, it’s not clear how many others didn’t make it.

They also believe that as more and more plastic accumulates in the ocean, creatures will have more and more rafts to float on and get from place to place — especially in the case of violent storms or tsunamis.

“There is huge potential for the amount of marine debris in the oceans to increase significantly,” added James Carlton, who is also an invasive species expert with the Maritime Studies Program of Williams College and Mystic Seaport in Connecticut.

“In many ways they just haven’t had much opportunity in the past. Now, plastic can combine with tsunami and storm events to create that opportunity on a large scale.”

Journal Reference: James T. Carlton et al. Tsunami-driven rafting: Transoceanic species dispersal and implications for marine biogeography. DOI: 10.1126/science.aao1498

Mars.

Geological deposits hint at ancient ocean on Mars’ surface

New evidence in support of the oceans-on-Mars theory has surfaced from a very spectacular source: geological deposits associated with tsunamis have been mapped on the red planet.

Mars.

Image credits Aynur Zakirov.

Scientists are fairly certain that at some point in the past, Mars held liquid water. But a more controversial topic is how much of it there was — namely, if Mars ever had oceans on its surface. A new paper published by an international team of researchers comes to support the idea that oceans did in fact once grace the face of Mars in style: with tsunamis.

“We found typical tsunami deposits along the dichotomy between the northern hemisphere and southern hemisphere of Mars, it supports that there was, at that time, a northern ocean,” Francois Costard, PhD, researcher at the Université Paris-Sud 11, Orsay Earth Science Department and director of research at the French National Center for Scientific Research (CNRS) and first author of the paper said of the sediment distribution on the northern plains of Mars.

These structures are known as lobate flow deposits and were first sighted by the Viking orbiters in the early days of martian research. They’re basically piles and piles of large rocks and other geological debris stacked below cliffs, with characteristic shape and topography. The deposits in the area the team was investigating (Vastitas Borealis Formation) were previously theorized to have been formed by mud volcanoes, glacier movement, or mud flows.

But the characteristics displayed by the lobade deposits are suspiciously similar to what you’d expect to see when a tsunami hits high-land and all the stuff it’s been moving anchors itself on the terrain.

“These lobate deposits propagate uphill from the northern plains and do so in close association with a potential palaeo-shoreline,” explains co-author Stephen Clifford from the Lunar and Planetary Institute in Houston, Texas.

“The predictions of the numerical modelling that François and his colleagues have done provide a very persuasive case for an ocean at this time. There’s also a second set of landforms that we see along the coastline called thumbprint terrain […] the reflection of the tsunami waves from the coast and their interaction with a second set of tsunami waves, predicted by the numerical modelling, would have resulted in sediment deposition that’s very similar to what we actually observe on Mars.”

The team believes the tsunami originated in what today is the Lomonsov crater in Mars’ Norther District, generated after a massive meteorite impacted in the middle of the ocean. The team believes waves as high as 150m followed the impact — suggesting that there was ample free water to be stirred by the asteroid, which can only mean an ocean.

(A) Thumbprint terrain showing a curving pattern of high-albedo mounds, low-albedo flat surfaces and terminal lobate deposits (black arrow.) (B) Study area. (C) Detail of convex pattern of the thumbprint terrain from (A) (black arrows indicating flow
directions).
Image credits Francois Costard et al., 2017, JGR.

The Lomonsov crates is a 120km-wide bowl named for 18th century Russian polymath Mikhail Vasilyevich Lomonosov. Its size suggests a very powerful impact, and the team believes it created two sets of waves. This first wave was an estimated 300m in height, and likely reached the paleo-shoreline of hills and plateaus in a matter of hours, depositing the lobate flows.

“It was a really large-scale, high speed tsunami. At the very beginning, a crater of 70km in diameter was created by the impact. This expelled a huge volume of water, with wave propagation at 60m/second,” Clifford adds.

Clifford says that the main takeaway from the research is that there was likely a large amount of liquid water to be found on the Martian surface of old, which “[has] implications for the total inventory of water on Mars.”

It’s likely that oceans housed the earliest of Earth’s life, so finding one on Mars would definitely improve the chances of life (at least, life as we know it) developing on the planet. And if there was once abundant water on our red neighbor, maybe it found a way to hold on until today.

Fingers crossed.

The paper “Modeling tsunami propagation and the emplacement of thumbprint terrain in an early Mars ocean” has been published in the Journal of Geophysical Research.

Powerful sound blasters can render tsunamis dead in the water, new study shows

Blasting high-powered acoustic waves at tsunamis could break their advance before reaching the shoreline, a new theoretical study has shown.

Tsunamis are one of the most dramatic natural phenomena we know of, and they’re equally destructive. These great onslaughts of water are powered by huge amounts of energy — on a level that only major landslides, volcanoes, earthquakes, nukes, or meteorite impacts can release. And when they reach a coastline, all that water in motion wipes infrastructure and buildings clean off.

[MUST READ] How tsunamis form and why they can be so dangerous

Traditionally, there are two elements coastal communities have relied on against tsunamis: seawalls and natural barriers. Seawalls are man-made structures that work on the principle of an unmoving object, resisting the wave’s kinetic energy through sheer mass. Natural barriers are coastal ecosystems, typically mangrove forests or coral reefs, that dissipate this energy over a wider area and prevent subsequent floods. Each approach has its own shortcomings however, such as high production and maintenance cost or the risk of being overwhelmed by a big enough tsunami.

Dr Usama Kadri from Cardiff University’s School of Mathematics thinks that the best defense is offence — as such, she proposes the use of acoustic-gravity waves (AGWs) against tsunamis before they reach coastlines.  Dr Kadri proposes that AWGs can be fired at incoming tsunamis to reduce their amplitude and disperse energy over a larger area. Ok that’s cool, but how does it work?

The tsunami whisperer

Waves are a product of the interaction between two fluids (air-water) and gravity. Friction between wind and the sea’s surface causes water molecules to move sideways and on top of one another, while gravity pulls them back down. Physically speaking, ‘waves’ are periodic wavetrains — and as such, they can be described by their period (length between two wave crests), amplitude (height), and frequency (speed).

One thing you can do with periodic waves is make them interfere constructively or destructively — you can ‘sum up’ two small waves to make a bigger one, or make them cancel out. Apart from a different source of energy, tsunamis are largely similar to regular waves, so they also interfere with other waves. Here’s where AGWs come in.

Think of AGWs as massive, sound-driven shock-waves. They occur naturally, move through water or rocks at the speed of sound, and can stretch for thousand of kilometers. Dr Kadri shows that they can be used to destructively interfere with tsunamis and reduce their amplitude before reaching the coast. Which would prevent a lot of deaths and property damages.

“Within the last two decades, tsunamis have been responsible for the loss of almost half a million lives, widespread long-lasting destruction, profound environmental effects and global financial crisis,” Dr Kadri writes in her paper. “Up until now, little attention has been paid to trying to mitigate tsunamis and the potential of acoustic-gravity waves remains largely unexplored.”

“The main tsunami properties that determine the size of impact at the shoreline are its wavelength and amplitude in the ocean. Here, we show that it is in principle possible to reduce the amplitude of a tsunami, and redistribute its energy over a larger space, through forcing it to interact with resonating acoustic–gravity waves.”

Her paper also shows that it’s possible to create advanced warning systems based on AGWs, which are generated with the tsunami and induce high pressures on the seabed. She also suggests harnessing these natural AGWs against tsunamis, essentially using nature’s own energy against itself.

The challenge now is to develop technology that can generate, modulate, and transmit AGWs with high enough accuracy to allow for interference with tsunamis. She admits that this won’t be easy to do, particularly because of the high energy required to put a dent in the waves.

The full paper “Tsunami mitigation by resonant triad interaction with acoustic–gravity waves” has been published in the journal Helyion.

What are tsunamis and how they form

Most waves form due to winds or tides, but tsunamis have a different cause altogether. A tsunami is most often formed by an earthquake, but it can also be formed by an underwater landslide, volcano eruption or even meteorite.

The process is fairly complex, so let’s start digging into it.

The Great Wave off Kanagawa, an artistic depiction of a tsunami by Katsushika Hokusai.

What is a tsunami

“Tsunami” is a Japanese word meaning “harbor wave,” but that doesn’t say much about their nature, and tsunamis are not nearly restricted to harbors. A more accurate term would be “seismic sea waves,” and it would describe them more accurately. However, tsunami has stuck and it’s what everyone uses today. People sometimes refer to them as “tidal waves,” but that term is technically incorrect and should be avoided in this context.

Tsunamis are indeed waves, but unlike wind waves, they have a much larger wavelength. Think a bit about waves — in the context of physics, not in the context of sea waves. A defining characteristic of every wave is its wavelength. Wind waves have short wavelengths which can be clearly seen on any shoreline. They come in every few seconds, with a few meters  in between — sometimes, even less. But a tsunami has a huge wavelength, oftentimes longer than a hundred kilometers and this is why they are so dangerous (more on that a bit later). Tsunamis are almost always not singular waves, but come in as train waves.

How tsunamis form – earthquakes

The vast majority of tsunamis form due to earthquakes — specifically tectonic tsunamis. As an earthquake happens, the ground beneath the water is moved up and/or down abruptly and as this movement happens, a mass of water is displaced and starts moving in all directions. This marks the start of a tsunami.

The displaced water starts to move as a wave. At this point, it has a very low amplitude as it is located in deep water (earthquakes on the coastline rarely cause tsunamis). Tsunamis in open water are usually shorter than 0.3 meters (12 inches).

 

Image by Régis Lachaume. Propagation of a tsunami offshore, showing the variation of wavelength and amplitude as a function of depth.

As the wave starts moving towards the shore, a series of events begin to occur. First of all, water gets shallower and shallower. As a result, the height of the tsunami starts to increase, and can increase dramatically. This is the main reason why these waves are so dangerous: They carry on huge masses of water. When they get closer to the shoreline, the volume of the tsunami remains constant, but because the water gets shallower, their height starts to increase.

The 3D simulation below shows how the process is taking place — note the waterline retreating before the tsunami hits. This is called a drawback.

 

Also, the shallow water somewhat slows down the waves and the waves start getting closer together. In the deepest parts of the ocean, tsunamis can travel faster than a jet, at 970 kph (600 mph). This means that in only a few hours, it can cross entire oceans.

Tsunamis don’t stop once they hit land. Much of their energy is dissipated and reflected back, but some of it is still maintained and tsunamis will continue to travel inland until all their energy is gone. So don’t think that if you’re a bit farther from the beach, you’re safe. In some rare instances, tsunamis can also travel up river valleys.

How tsunamis form — from other sources

In rare cases, tsunamis can also be caused by landslides, volcano eruptions, and meteorites. In all cases the main principle is the same — a water mass is displaced and as it nears the shoreline it starts growing in height. However, the displacement mechanism differs.

Landslide

Underwater, landslides are often similar to volcanoes that avalanche into the sea. This process happens as a result of an earthquake, so in a way, the main source is still an earthquake. However, earthquakes can also merely loosen landmass which starts falling at some later point.

Lituya Bay, Alaska, is an area prone to tsunamis (via Wikipedia).

Volcanoes

Volcanoes can form tsunamis through two mechanisms. Either they collapse or they eject matter with such strength that they uplift the water. In the first case, land-based volcanoes can also cause tsunamis, if they are very close to the sea.

Meteorites

If you’ve ever thrown a pebble into the water, you’ve seen that it creates ripples. The meteorite works in pretty much the same way, except it creates huge ripples. This kind of tsunamis are really rare, but there is an instance in 1958 where such a wave was created by rockfall in Lituya Bay, Alaska.

Why tsunamis are so dangerous

Tsunamis are not always colossal waves when they come into the shore. According to the USGS, “… most tsunamis do not result in giant breaking waves (like normal surf waves at the beach that curl over as they approach shore). Rather, they come in much like very strong and very fast tides (i.e., a rapid, local rise in sea level).”

By now, you should have a pretty clear idea why tsunamis are so dangerous. They can be very long (100 kilometers is a reasonable length), very high (the 2011 Japan tsunami measured over 10 meters) and can travel extremely fast without losing much of their energy. An earthquake far into the ocean can send several devastating tsunamis hundreds or even thousands of kilometers away.

2004 tsunami

A map of the 2004 tsunami with the highlighted epicenter.

In 2004, an earthquake with the epicenter off the west coast of Sumatra, Indonesia struck with a magnitude of 9.1–9.3. The Indian Plate was subducted by the Burma Plate and triggered a series of devastating tsunamis, some over 30 meters high. The tsunamis killed over 230,000 people in 14 countries, being one of the biggest natural disasters in human history. It is just one in many tragic examples highlighting the sheer force of tsunamis.

Safety for tsunamis

  • The first thing to do is to stay informed.

Since science cannot predict when earthquakes will occur, we cannot determine exactly when a tsunami will be generated. However, that doesn’t mean we’re clueless. With the aid of historical records of tsunamis and numerical models of their size and speed, we can get a pretty good idea as to where they’re likely to be generated. You should always know if you’re in a tsunami risk zone. An estimated 85% of all tsunamis have been observed in the Pacific Ocean in the “Ring of Fire,” but other areas can be dangerous as well and as we mentioned above, tsunamis can also travel great distances.

  • If you feel an earthquake in a low-lying, coastal area, keep calm and move away from the coast. Not all earthquakes cause tsunamis, but some do.
  • If you see a large water mass retreating, this is the drawback. It’s a telltale sign that a tsunami is coming. A 10-year-old girl saved many lives in 2004 because she knew this from her geography lessons.
  • Tsunamis are rarely singular waves — they come in packs, so if one hits, don’t think it’s ‘all clear’ – more may be on their way. Earthquakes also often have replicas, which in turn can cause tsunamis.
  • Be on the lookout for tsunami warnings. Tsunamis are fast, but they still take some time to travel. So if you know of an earthquake nearby, check a tsunami forecast and see what it says. Also keep in mind that a small tsunami on one beach can be a big one on a nearby beach. Underwater topography can play a massive role.
  • Buildings are no protection against a tsunami. Going farther away from the beach is the best thing you can do.
  • If you’re somehow on a boat or ship and there’s a tsunami coming your way, it may be smarter to move your ship farther into the ocean where the tsunami is smaller. However, this can be very risky. Stay tuned to your local radio, marine radio, NOAA Weather Radio, or television stations during a tsunami emergency.
  • Whatever you do, don’t purposely go to the beach to see a tsunami. Seriously. It will outrun or outdrive you and it’s not safe at all.

 

Tsunami Warning Lifted After Magnitude 7.8 Quake Off Indonesia

Indonesian authorities lifted a tsunami warning issued after a magnitude 7.8 earthquake struck off the island of Sumatra – the largest earthquake since the 2004 disaster.

The U.S. Geological Survey said the epicenter was about 500 miles west-southwest of Padang, Indonesia and 529 miles north-northwest of the Cocos Islands. Source: USGS

“There is no info on casualties or damages yet,” Sutopo Purwo Nugroho, a spokesman at the national disaster mitigation agency, said via text message. “The tsunami warning is based on modeling, while tsunami buoys in Indonesian waters haven’t reported any existence of a tsunami. Many buoys are broken and not functioning, so we don’t know whether the potential for a tsunami in the waters is true or not.”

According to the United States Geological Survey, the earthquake struck at 19:49 local time (12:49 GMT). It said the epicentre was 805km (500 miles) south-west of the city of Padang, and 24km deep.

Thankfully, there seems to be no damage caused by the earthquakes and any tsunamis should have already hit by now, so the coast seems to be safe for now. Telephone communication was reported to be down in the Mentawai island chain, which is closer to the epicenter.

The tectonics of Indonesia are very complex, as it is a meeting point of several tectonic plates, which makes it one of the most active earthquake hotspots in the world. In 2004, a massive 9.1 magnitude earthquake struck Indonesia, with the resulting tsunami killing 230,000 people in 14 countries, and inundating coastal communities with waves up to 30 metres (100 ft) high. It was one of the deadliest natural disasters in recorded history.

California faces tsunami risk – L.A. specifically threatened

It’s not just the San Andreas fault – a new study published in the Journal of Geophysical Research reports that there are several long faults on the U.S. West coast which can cause significant earthquakes, as well as tsunamis.

This map shows the California Borderland and its major tectonic features, as well as the locations of earthquakes greater than Magnitude 5.5. The dashed box shows the area of the new study. Large arrows show relative plate motion for the Pacific-North America fault boundary. Mark Legg

“There are many active faults offshore southern California which could produce greater then magnitude 7 quakes and tsunamis,” Mark Legg, who runs a Southern California consulting firm called Legg Geophysical and is the lead author of the study, said.

Geologists gave a collective criticism to the big-budget San Andreas movie, labeling it as a “classic” disaster movie with little science behind it. But that doesn’t mean that California isn’t threatened by seismic activity; the San Andreas area is way overdue for a major earthquake, and it’s likely gonna be big. The surveys of the region show a “complicated logjam” of faults produced by the movement of the Pacific Plate, sliding in relative motion to the North American Plate.

“What they were searching for are signs, like those seen along the San Andreas, that indicate how much the faults have slipped over time and whether some of that slippage caused some of the seafloor to thrust upwards,” the American Geophysical Union, which publishes the journal, said, in a press release.

Larger imageSCEC Community Fault Model. This map shows the 3-dimensional structure of major faults beneath Southern California. Image via Earthquake Country.

Legg said that while most geophysical studies (and movies) focus on the inland San Andreas fault, offshore faults still hold a great potential for damage. A geological fault is a planar fracture or discontinuity in a volume of rock, accompanied by major displacement. Most major faults emerge at areas of tectonic pressure, usually at the edge of tectonic plates. He and his colleagues gathered seafloor bathymetry data which revealed that two of the largest faults (the Santa Cruz-Catalina Ridge Fault and the Ferrelo Fault) have advanced in recent decades and are now connected to the smaller faults in the Borderland. Connected faults can be a major problem because they cause a domino-like effect, where movements on one fault trigger further movement and displacement on other faults.

A schematic block model of Southern California showing the motion of the Pacific and North American plates, and the big bend of the San Andreas fault where the plates squeeze together. Image via Earthquake Nation.

“The more connected the faults are, the more they can cause larger earthquakes,” said Paul Umhoefer, a geologist at Northern Arizona University. “The more detailed data that was gathered in this study is important for judging whether there is an earthquake and tsunami hazard.”

The good news is that even if a tsunami emerges, it won’t be as large as tsunamis generally get in subduction areas. Most tsunamis are caused by earthquakes generated in a subduction zone, an area where an oceanic plate is being forced down into the mantle by plate tectonic forces. But even if a 2 meter tsunami is generated, it could cause massive damage on the coast.

Legg also warned that we can’t even understand what damage a potential tsunami might cause, because we don’t have enough bathymetry data on the U.S. West coast.

“We’ve got high resolution maps of the surface of Mars,” Legg said, in a statement. “Yet we still don’t have decent bathymetry for our own backyard.”

 

Magnitude 6.8 earthquake strikes Northern Japan, small tsunami created

A magnitude 6.8 earthquake (initially 6.9) has struck Northern Japan earlier today, with a small tsunami striking the coast without any significant damage. The tsunami was on the order of tens of centimeters.

japan earthquake

There was some worry, despite Japan being one of the most well prepared countries in the world to deal with earthquakes.

“Overall, the population in this region resides in structures that are resistant to earthquake shaking, though some vulnerable structures exist”, the USGS website wrote.

The Iwate Prefecture is largely rural, with a population of approximately 1.3 million people. The area also has a nuclear power plant, but there was absolutely no risk of damage to it. A tsunami warning was issued initially, but was then canceled, after seismologists learned that it won’t be a big one. More as a precaution, local trains have suspended activity for now.

Recent earthquake in the areas have been dangerous through secondary hazards such as landslides and fires, but in this case, it seems like there will be no casualties.

This is still a developing story, we’ll keep you posted as further developments unfold.

Aleutian islands earthquake.

7.9 magnitude earthquake strikes offcoast Alaska. Tsunami alert issued for Rat and Aleutian Islands

A 7.9 magnitude earthquake has struck deep beneath the ocean floor near Alaska’s Aleutian islands, triggering a small tsunami.

Aleutian islands earthquake.

The Aleutian Islands.

Initially, a tsunami warning was issued for the area, but it was then downgraded to an advisory. Still, 200 residents of the town of Adak were evacuated to higher ground. The good news is that no injuries was reported – nor was any material damage.

The reason why this huge earthquake was so silent on the surface is the depth: the focal point was at about 114 km below surface. Shallow earthquakes are typically the most dangerous, because most of their energy is located close to the surface, and most of it reaches the surfaces; they also tend to generate huge surface waves which cause the most massive damage. With deeper earthquakes, most of the energy is lost on the way to the surface, and the type of waves they tend to generate are less harmful for humans.

This was a likely subduction zone earthquake, with the Pacific plate subducting below the American plate; the seismic event is the result of oblique normal faulting at moderate depths. At the location of this event, the Pacific plate subducts northward beneath the North America plate at a rate of approximately 59 mm/yr.

The locus of the June 23 event is a very seismically active region, with 26 events of M 7 or greater having occurred within 250 km since 1900.Usually, it’s not earthquakes directly that cause most of the damage, but the follwing tsunamis.

If you want to read an excellent, detailed explanation of the underlying geology of the area read this USGS article.

 

Earthquake acoustics can indicate if a massive tsunami is imminent

As bad as earthquakes can be, and we’ve recently had our fair share of earthquakes around the world, the tsunamis they generate can be even worse.

tsunami_release

When an earthquake has a significant effect in a body of water, it displaces large quantities of water – and it is that displacement which causes the huge waves which we call tsunamis. They are fundamentally different than usual waves; rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly rising tide, and for this reason they are often referred to as tidal waves.

But computer simulations conducted by geophysicists from Stanford revealed that sound waves in the ocean produced by the earthquake reach land tens of minutes before the tsunami, and if correctly interpreted, they can offer a tsunami warning.

Although we are very good at detecting all earthquakes that take places on our planet, including those that take place underwater, tsunami warnings are still rather lackluster. It takes a lot of time after the earthquake before they can tell if a tsunami will be created, and information about its size is very hard to estimate.

Discovering the signal

Interestingly enough, finding the signal came as somewhat of a surprise. They were modelling the signal from an epicenter in the Japan Trench, a subduction zone about 40 miles east of Tohoku, the northeastern region of Japan’s larger island.

japan trench

They used both known geologic and tectonic features of the trench, and used the cluster of supercomputers at Stanford’s Center for Computational Earth and Environmental Science (CEES) to simulate how the tremors moved through the crust and ocean. They applied the model to some documented tsunamis, and it was retroactively able to predict the seafloor uplift which is directly connected to tsunami height.

“We’ve found that there’s a strong correlation between the amplitude of the sound waves and the tsunami wave heights,” Dunham said. “Sound waves propagate through water 10 times faster than the tsunami waves, so we can have knowledge of what’s happening a hundred miles offshore within minutes of an earthquake occurring. We could know whether a tsunami is coming, how large it will be and when it will arrive.”

Even though they created the model only for the Japan Trench, they believe they can apply it to tsunami-generating areas throughout the world, though the parameters of the signal are greatly dependent on the geology of the zone.

“The ideal situation would be to analyze lots of measurements from major events and eventually be able to say, ‘this is the signal’,” said Kozdon, who is now an assistant professor of applied mathematics at the Naval Postgraduate School. “Fortunately, these catastrophic earthquakes don’t happen frequently, but we can input these site specific characteristics into computer models – such as those made possible with the CEES cluster – in the hopes of identifying acoustic signatures that indicates whether or not an earthquake has generated a large tsunami.”

Geophysicists also pointed out that identifying the tsunami signal doesn’t profie a complete warning system – underwater sound detectors called hydrophones (as opposed to those used on land which are called geophones) would need to be deployed on the seafloor or on floating buoys to detect the signal, which then has to be analized – both of which can be pretty costly. Then there’s also the delicate matter of the degree of certainty which has to be reached before alarming the people.

Via Stanford

Tsunami strikes Solomon islands following big earthquake

A massive earthquake struck Wednesday east of Kira Kira in the Solomon Islands, with several already confirmed victims and injuries.

tsunami solomon

“At 12 minutes past midday, a 7.9 earthquake in the Santa Cruz Islands (near the Solomon Islands) occurred. A shallow event.” He said. “The nearest part from our location estimate is an island called Ndeni, which is part of the Santa Cruz Islands. They would have had quite strong shaking and could potentially have some damage there from shaking.”

For other areas there is no big tsunami alert, though waves somewhere between 90 cm’s and 1.5 meters have remained localized around the coast of the Solomon Islands. A flood alert has also been issued.

Professor James Goff, Director of the Tsunami and Natural Hazards Research Group at the University of New South Wales feared the worst when the magnitude 8.0 quake struck at the Santa Cruz Islands, part of the South Pacific nation of Solomon Islands on Wednesday from a depth of 5.8 kilometers.

“The Mag 8.0 Santa Cruz earthquake was originally reported by the United States Geological Survey to be about 5.8 km deep which made me think “oh no, here we go again, this will be a bad one”, but subsequent bulletins from the Pacific Tsunami Warning Center placed it at 33 km deep which at the very least reduces the likelihood of the tsunami being too bad.”

Solomon-islands-quake-001tsuna

The size of both the earthquake and the tsunami took seismologists somewhat by surprise.

“In reality we know very little about the long-term earthquake and tsunami activity of the entire Solomon Islands region and so cannot say with any confidence whether this type of event we have seen today is out of the ordinary or how often we might expect it to happen in the future. Much work needs to be done to improve our understanding of such events in the Solomon Islands for the safety of both local and regional communities.”, he said.

Medieval tsunamis in the Alps – could happen again

If you think about tsunamis, you’ll probably think about Japan, Indonesia, maybe America… the last place you’d image would be the Alps, right? Well, you might have to go back to that.

About 1500 years ago, a massive flood took place in Geneva, Switzerland, wiping out everything in its path, crippling the local community. Now, researchers believed they found the culprit in the form of a tsunami, a threat which is still pretty much posed today. The presumed wave was caused by a huge landslide, wrecking the entire medieval city, which was probably already a known trading hub at the time.

Far from the ocean, the massive wave had its origin in the Rhône River, which feeds and flows through Lake Geneva. The Swiss team analyzed a huge sediment deposit at the bottom of the lake and came to the conclusion that it once belonged above the lake and slid into the Rhône near the place it flows into the lake. The sudden splash created a tsunami that flower through the 580-square-kilometer lake towards Geneva, the study suggests; the height would have been between 3 and 8 meters, quite enough for that period.

But perhaps more important, researchers warm, is that this danger isn’t a thing of the past. A similar event happening today would cause much greater damage, significantly affecting not only Geneva, but also the neighboring cities of Lausanne, Nyon, and Thonon-les-Bains, threatening over 300.000 people who live in the area. The damage could be amplified by the fact that towards Geneva, the lake narrows, creating a funnel effect which acts as an amplified for waves. Still, there’s no need to panic, because there isn’t any hint of an immediate threat. Still, it is something to consider.

“If this has happened five to six times since the last glaciation, there’s reason to believe it could happen again in the future,” said University of Geneva geologist Guy Simpson, who study team’s modeler. “A three-meter [ten-foot] wave that hit Geneva today would be a scary wave.”

The research will be published in Nature

Scientists report from Fukushima exclusion zone, analyze tsunami

You probably remember the massive 9.1 earthquake that struck Japan last year and the subsequent problems that followed – most notably the huge tsunamis that struck the Fukushima nuclear plant, bringing it close to a meltdown. Now, according to the first scientific assessment made on the spot, the tsunami was indeed as formidable as the first estimates claim.

Big tsunamis, big data set

They conducted surveys along 2,000 kilometres of coast, thus creating the biggest tsunami data set the world has ever seen so far, but until now, no verified data was obtained from the impact perimeter: the 20-kilometre-radius restricted zone around the crippled plant, where scientific work had been forbidden.

However, a team of seven set out on a laudable two day mission to determine the height and inland penetration of the tsunami that struck the coast of Japan about an hour after the massive temblor struck. The team also included two local guides and two local authorities, and was led by Shinji Sato, a civil engineer at the University of Tokyo. By analyzing the ‘tsunami marks’, like the water damage, the debris, and trees, they confirmed that the waves were at least 14-15 meters high, just as big as the first estimates claimed, and the biggest height they estimated was 21 meters. Still, the team was not allowed to get closer than 2 km to the nuclear plant.

Clues, schools and cows

Finding relevant clues about tsunamis after almost a year was definitely a challenge, and the team stumbled upon some really interesting things there. For example, some buildings seemed to have not taken any damage whatsoever; aside for a dent in its chimney, the gymnasium of Ukedo Elementary School in Namie, located less than 5 km away from the plant, looked intact. The banners inside were untouched, and a small Japanese flag was intact. At a restaurant from town, researchers found a pristine newspaper dated 11 March 2011 – the date of the earthquake. But without a doubt the biggest surprise was when they met a herd of cows; the animals somehow survived the tsunami and adapted to the newly created environment, leading quite the life now.

“I often scratched my head at the juxtaposition of utter devastation and relative intactness,” says Yeh.

Scientists will now analyze the data to refine computer simulations and better understand how the sea contour influenced the tsunami; many believe the tsunamis which struck the Fukishima power plant were actually a combination of two different waves, one coming from the North and one coming from the South. It is very important to gather valuable information from this tragedy, in order to understand how we can protect ourselves from other such disasters.

“Nobody else has obtained this kind of information,” says Philip Liu, a tsunami researcher at Cornell University in Ithaca, New York, who was not involved in the survey. “It’s valuable evidence of how the tsunami has behaved.”

Via Nature. Photo via National Geographic.

Researchers at NASA’s Jet Propulsion Laboratory created a 3-D ocean model replicating the March 11, 2011 tsunami.

Japan’s tsunami was actually a double killer wave

Researchers at NASA’s Jet Propulsion Laboratory created a 3-D ocean model replicating the March 11, 2011 tsunami.

Researchers at NASA’s Jet Propulsion Laboratory created a 3-D ocean model replicating the March 11, 2011 tsunami. (c) NASA

This summer Japan was hit by a tremendous 9.0 Richter scale earthquake, which generated one of the most powerful tsunamis in recorded history. The event killed thousands, left countless others homeless, caused major damage to the Fukushima nuclear power plant , which lead to  radiation leakage and more than $130 bln in damage. Now, new details amassed from correlated weather satellite footage shows that the Japan tsunami was so powerful since it came in a double bundle – the result of two merged tsunamis.

The idea of composite tsunamis, in which two or more wave fronts merge to become one giant tsunami, has been hypothesized before by scientists, however this is the first time it has been observed and confirmed. The Japan tsunami was viewed  by satellites positioned in the moment the giant wave front struck the coastline, which managed to capture data. Thus, the NASA-European Jason-2, NASA-French space Agency satellite altimeter, and the ESA EnviSAT, all satellites equipped with altimeters, observed the tsunamis as they grazed the ocean with centimeter precision.

Remarkably enough, the whole find was filled with a stroke of luck.

“It was a one in 10 million chance that we were able to observe this double wave with satellites,” principal investigator Y Tony Song said.

“Researchers have suspected for decades that such ‘merging tsunamis’ might have been responsible for the 1960 Chilean tsunami that killed about 200 people in Japan and Hawaii, but nobody had definitively observed a merging tsunami until now,” he added.

“It was like looking for a ghost. A NASA-French Space Agency satellite altimeter happened to be in the right place at the right time to capture the double wave and verify its existence.”

The researchers think that ridges and underwater mountains can deflect parts of the initial tsunami wave to form a number of wave fronts. Such a huge wave was able to travel long distances without losing power, according to the researchers, who presented their findings at the American Geophysical Union meeting in San Francisco. The scientists say the data gathered by the satellites may help researchers better predict how future tsunamis will impact coastlines based on the underwater topography in earthquake zones.

 

Underwater volcanoes beneath the Antarctic seas. The peak in the foreground is thought to be the most active, with eruptions in the past few years. (c) British Antarctic Survey

Hugely tall underwater volcanos discovered

In the first ever-survey of its kind, geologists have managed to discover a chain of massive underwater volcanoes, some as tall as 2 miles, underneath the Antarctic waters near the South Sandwich Islands in the remote Atlantic Ocean.

The South Sandwich Islands have always been known for their evident volcanic activity, ever since their discovery by famous explorer Captain Cook in 1775. What happens beneath the islands however remained more or less ignored, until recently when scientists mapped in great detail the area of the seafloor around these islands.

Underwater volcanoes beneath the Antarctic seas. The peak in the foreground is thought to be the most active, with eruptions in the past few years. (c) British Antarctic Survey

Underwater volcanoes beneath the Antarctic seas. The peak in the foreground is thought to be the most active, with eruptions in the past few years. (c) British Antarctic Survey

Scientists used sonar scanners to trace each shape and slope of the volcanoes, which fed them back some incredible data – 12 new undersea volcanoes, some topping even two miles. Some are still active, while others have been found collapsed in craters as large as 3 miles.

The volcanoes came as a consequences, scientists claim, of the tectonic dance between the South American continental plate sliding under the South Sandwich plate to the east. Water gets slipped beneath one of the plates and deep into the interior of the earth, from where it escapes upward, springing a molten rock eruption along the way.

Underwater volcanoes form parallel to the plane lines and as they steadily build up, they form new crust which will eventually someday after millions of year link with a continent. Scientists hope to learn more by studying the process in greater detail, and gain a greater grasp upon the formation of continents.

“We have GPS data to show that the South Sandwich Islands are moving east very fast indeed with respect to Africa,” Ian Dalziel of the University of Texas at Austin said. “It’s a very active system.”

Researchers warn however that underwater volcanoes could cause highly damaging tsunamis, since such volcanoes often have unstable slopes.

“This is quite well known,” Phil Leats of the British Antarctic Survey who led the new efforts said “Clearly this has happened in this area. We can see the scars. We can see the quite large slump deposits, which must have caused quite large tsunamis, so clearly it’s an area where this kind of hazard does exist.”

The survey was made by the  British Antarctic Survey.

via

Monitoring radioactivity levels near the Fukushima Daiichi nuclear power plant. Photograph: Christian Slund/Reuters

Japan raises nuclear crisis level to that of Chernobyl

Japan’s nuclear crisis level has been regulated from level 5 to 7  by the International Atomic Energy Agency, at the top of the nuclear hazard scale and right on par with the 1986 Chernobyl incident, according to the level of radiation released in the accident. The new ranking signifies a “major accident” with “wider consequences” than the previous level, according to the Vienna-based IAEA.

“We have upgraded the severity level to 7 as the impact of radiation leaks has been widespread from the air, vegetables, tap water and the ocean,” said Minoru Oogoda of Japan’s Nuclear and Industrial Safety Agency.

The decision was made after assessments of data on leaks of radioactive iodine-131 and cesium-137 showed critical levels of radiation.

“We have refrained from making announcements until we have reliable data,” NISA spokesman Hidehiko Nishiyama said.

“The announcement is being made now because it became possible to look at and check the accumulated data assessed in two different ways,” he said, referring to measurements from NISA and the Nuclear Security Council.

As opposed to the Chernobyl crisis, however, the Fukushima Dai-ichi plant hasn’t experienced any reactor core explosions, despite hydrogen explosions occurred during the first waves of tsunami which hit Japan after the deadly 9.0 earthquake. Actually, the amount of radiation leaking from the Fukushima Dai-ichi nuclear plant is around only 10 percent of the Chernobyl accident.

The magnitude-9.0 earthquake that caused the tsunami immediately stopped Fukushima’s three reactors, but overheated cores and a lack of cooling functions led to further damage. Engineers have been able to drop water into the damaged reactors to cool them down, but leaks have resulted in the pooling of tons of contaminated, radioactive water that has prevented workers from conducting further repairs – and if it wasn’t enough, aftershocks on Monday briefly cut power to backup pumps, halting the injection of cooling water for about 50 minutes before power was restored.

It could take weeks or months to stabilize the reactors. And containing and cleaning up the radioactive material could take at least 10 years, at a cost of more than $10 billion.

Tsunamis in the Atlantic – unlikely, but possible

There’s been a lot of fuss around tsunamis lately, especially seen as Japan, perhaps the most prepared country in the world, was devastated by them. A tsunami in the Atlantic however, is a rare sight, due to the fact that that there are no subduction areas, the most common cause of tsunami-causing earthquakes.

Map of reported tsunamis; credit NOAA

However, even though the tsunami threat in the Atlantic region is quite low, it should definitely be taken into consideration, especially as millions of people live in low elevation areas around the Atlantic basin. The most famous example of a tsunami in the Atlantic took place more than 200 years ago, in 1755, in Lisbon, caused by what is believed to have been a 8.6 magnitude earthquake, generating waves as high as 12 meters and killing approximately 100.000 people; however, an event of this magnitude today would definitely do much more damage as the area is much more populated.

The latest major tsunami causing event took place in 1918, when a 7.3 earthquake struck Puerto Rico and generated tsunamis of 6-7 meters. However, the bad thing is that due to the fact that there is a low risk for those areas, there is little to no preparation made, so unfortunately, a big tsunami in the Atlantic basin would have absolutely devastating effects.

Japan engineers concede they might have to bury nuclear plant

As the nuclear situation at the Fukushima power plant continues to deteriorate, engineers start to ponder drastic options more and more seriously; it seems that the method which seems to have te best chances to work is the same one that was user in Chernobyl in 1986.

It is the first time operation leaders are admitting that burying the 40 year old complex is a serious option, as pumping water and droping it from helicopters seems to not work so well. However, even in this situation they still have to find a way to cool them down, which is more than complicated at the moment.

“It is not impossible to encase the reactors in concrete. But our priority right now is to try and cool them down first,” an official from the plant operator, Tokyo Electric Power Co, told a news

As Japan entered the second week after the 9.0 earthquake that generated tsunamis of over 10 meters, it’s worst crisis since WWII is far from being over. Already, 6.500 have officially been declared dead, with another 10.000 reported missing, and hopes are dropping with each passing day. Almost 400.000 people are homeless and battling near freezing temperatures, and the government also didn’t respond at its maximum capacity.

“An unprecedented huge earthquake and huge tsunami hit Japan. As a result, things that had not been anticipated in terms of the general disaster response took place,” Chief Cabinet Secretary Yukio Edano told a news conference.

Japan also raised the nuclear crisis rating from 4 to 5 out of a maximum of 7, but most experts claim the situation is even more dangerous.