Tag Archives: tsunamis

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.

Disturbing time-lapse animation shows Japan earthquakes

The 9.0 (it seems this is the actual magnitude) earthquake that hit Japan on the 11th of March created an absolutely incredible number of aftershocks, some of which were pretty intense on their own. However, a few days before it, as stress built up the subduction area between the Pacific and North American plates, one could easily see some foreshocks too.

The 7.2 temblor, which was one of these foreshocks, struck Japan on March 9, and it was pretty strong on its own; however, since the big earthquake started, aftershocks continue to rattle Japan, and for the past days, pretty much every significant earthquake in the world took place in that area.

Just a few hours after it, there were 19 reported aftershocks, and the estimated number now is over 100. This was the 4th biggest earthquake ever to be recorded, and despite the fact that aftershocks seem to decrease in intensity, there is no indication of them stopping any time soon. Before this, since 1973, there were only 9 earthquakes bigger than 7.0 recorded in Japan – now that number has increased greatly.

Quake moved Japan by at least 8 feet

The devastating seismic event that struck Japan is affecting the entire world, and even the entire planet. While smoke continues to rise from the catastrophic temblor, Japan seems to have moved 8 feet inland, or even more, according to the USGS.

“That’s a reasonable number,” USGS seismologist Paul Earle told AFP. “Eight feet, that’s certainly going to be in the ballpark.”

Friday’s terrible 8.9 tsunami unleashed a series of terrifying tsunamis that engulfed towns and cities on Japan’s coast, and caused the death of over ten thousand people.

The quake is the tectonic shift resulted from “thrust faulting”, along the boundary of the Pacific and North American plates. The Pacific plate “pushes” under the North American one at a rate of about 3.3 inches (83 millimeters) per year, but a major seismic event, such as this one, can give a significant push, with devastating consequences.

“With an earthquake this large, you can get these huge ground shifts,” Earle said. “On the actual fault you can get 20 meters (65 feet) of relative movement, on the two sides of the fault.”

This earthquake in Japan was just slightly less powerful than the one that killed 250.000 people in Sumatra, but almost 100 times more powerful than the one in Haiti.

“A magnitude 7.0 is much smaller than the earthquake that just happened in Japan,” he said. “We’ve had aftershocks (in Japan) larger than the Haiti earthquake.”

Japan earthquake causing damage of £100 bln, still rising

The sad loss of over 10.000 people caused by the M8.9 earthquake and the tsunamis it generated is not the only problem Japanese people will have to deal with; this major disaster is also the most costly in world history, a “title” previously held by Katrina in the US, with an estimate of £77  billion but with way less deaths.

The disaster caused a 6.2 per cent drop in Japan’s Nikkei share index, wiping £90 billion off stocks and shares traded there, and although this is not the highest concern at all right now, it is yet another difficult task to handle; furthermore, a significant part of the world is economically addicted to Japan, so if they were to suffer a recession, probably the whole world would have to face another recession.

Andre Bakhos, the director of market analytics at Lek Securities in New York, said: “The earthquake could have great implications on the global economic front. If you shut down Japan, there could be a global recession.”

The earthquake in Japan had an estimated magnitude of 8.9, making it one of the top five earthquakes ever to be recorded. The tsunamis it generated violently struck not only Japan, but other parts of the world as well, and because the electricity dropped in most of the country, several nuclear plants are in danger of a meltdown. So far, the deathtoll goes way beyond 10.000 people.

Small hilltop city becomes refuge for earthquake and tsunami survivors

In the aftermath of the earthquake that violently struck Japan and the tsunamis it generated, the small, industrial city of Hitachi emerged unscathed from what Prime Minister Naoto Kan has described as Japan’s “worst crisis since the Second World War”, making it somewhat of a refuge for the hordes of refugees that flooded from many parts of the country.

How the city managed to escape unharmed from the seismic disaster is credited to its topography – basically the city was built on some a higher ground. The Friday temblor, which ravaged the entire country and created several aftershocks and tsunamis is estimated to have killed at least 10.000 people, and will probably cause additional deaths. In Hitachi, however, things are very different.

“We were so lucky really. I haven’t heard of any serious injuries amongst people I know,” says a security guard keeping watch outside the Hitachi Futo shipping company’s lot in the city’s harbor.

As aftershocks and tsunamis continue to rattle the area, more and more people continue to move to this lucky town – several thousands of refugees are now literally at the gates of the city, waiting and hoping for shelter, and a steady roof above their heads.

Magnitude of Japan earthquake takes scientists by surprise

It’s no mystery for anybody that the earthquake in Japan is one of the largest ever to be recorded in history, and it’s no mystery for anybody that Japan is an area with numerous seismic events, but the magnitude of this one exceeded greatly all expectations, even the most pessimistic one.

The 8.9 magnitude (or 9.0 according to other measurements) earthquake that struck the northeastern coast of Japan “is going to be among the top 10 earthquakes recorded since we have had seismographs,” said seismologist Susan Hough of the U.S. Geological Survey in Pasadena. “It’s bigger than any known historic earthquake in Japan, and bigger than expectations for that area.”

That particular portion of the Ring of Fire, as it is called, was expected to create a 8, maybe 8.5 magnitude temblor, but something as big as 8.9 is quite surprising; this may not seem like a big difference, but the Richter scale is a logarithmic one, so a 9 earthquake is 10 times more powerful than a 8 earthquake.

The thing is, temblors this big in the crust take place when a long, relatively straight fault line ruptures; a classical example for this would be Peru or Chile, but not Japan, because that tectonic plate boundary is not straight at all, but very irregular. According to USGS, an earthquake this big would require a huge rupture, of more than 300 miles. To top things off, this type of earthquake was perfect for tsunami generation, because it was very big, and at a very shallow depth.

Brilliant picture shows tsunamis estimated heights

This picture, created by a computer model at NOAA displays the expected heights of the tsunamis created by the 8.9 earthquake in Japan (which may be “upgraded” to 9.0 – calculating magnitudes is a pretty delicate issue).

Of course the largest wave heights are expected near the epicenter, off the coast of Sendai, Honshu, Japan. Generally speaking, the heights will decline with distance, but the near-shore heights will also decrease; for example coastal Hawaii will not expect heights of that encountered in coastal Japan.

The earthquake is one of the most powerful ever to be recorded, and it took most geophysicists and geologists by surprise, as almost nobody was expecting an event of this magnitude. Tsunamis caused even more damage, and things can get significantly worse for Japan (and not only) if the meltdown of several affected nuclear plants isn’t prevented. It seems however that the Japanese are handling the situation very well, and everybody is doing everything they can to limit the damage, and most of all, casualties.

Radiation Level at Fukushima nuclear plant is 1000 times over accepted level after earthquake

The damage caused by the 8.9 earthquake in Japan is far from being over – asa matter of fact, unfortunately, it may very well just be starting. The earthquake and the tsunamis it created cut down power supply throughout a major part of Japan, and so the cooling system of several power plants was unable to do its job.

As a result, the radiation level at the Fukishima power plant is about 1000 times bigger than the accepted level, and technicians are desperately trying to figure out ways to prevent a meltdown, which would have catastrophic results; one way to do this would be to release steam that has been vaporized by heat from the nuclear core, which would lower the pressure, and thus, the temperature.

“It’s possible that radioactive material in the reactor vessel could leak outside but the amount is expected to be small and the wind blowing towards the sea will be considered,” Chief Cabinet Secretary Yukio Edano told a news conference.

The earthquake which shook Japan to its very core caused all sorts of issues, and this latest nuclear problem is extremely hard to tackle. The good news however, is that eleven reactors close to the epicenter shut themselves down when they sensed the earthquake.

“Reactors shut themselves down automatically when something called ‘ground acceleration’ is registered at a certain point, which is usually quite small. It will instantly drop control rods into the [nuclear] core,” Professor Tim Albram, a nuclear fuel engineer at the University of Manchester in the U.K., explained to the press.

How this whole situation will be handled remains to be seen, but things seem pretty dire at the moment; hopefully though, there will be no further complications, as Japan has already seen too many during these two days.

Japan in more trouble after an explosion at a nuclear plant

The earthquake that occured yesterday near the coast of Japan, the 4th most powerful earthquake ever to be recorded, is causing even more problems, after the direct damage, the aftershocks, the tsunamis, and the fire tsunamis; this time, things can get way, way bigger and worse, and the disaster toll keeps rising.

An explosion at a nuclear power plant destroyed a nuclear power station created fears that the a disastrous meltdown could happen, which would definitely cause a huge number of human casualties not only in Japan, but in neighbouring areas as well. The explosion was caused by the earthquake and the tsunamis that devastated Japan, and caused (by now) an estimated number of 1300 deaths, already.

The Fukushima Dai-ichi plant, the one in case, caused worries that led to an immediate evacuation of all the workers and people in the area, but experts have yet to find out what lies behind this explosion.

“We are now trying to analyze what is behind the explosion,” said government spokesman Yukio Edano, stressing that people should quickly evacuate a six-mile (10-kilometer) radius. “We ask everyone to take action to secure safety.”

The trouble began after the 8.9 magnitude earthquake and the tsunamis it created knocked out all electricity from the area. Other disturbing news is that the Kyodo news agency said rail operators lost contact with four trains yesterday, and still haven’t found them today. Japan has also declared states of emergency for five other nuclear reactors, all of which are in danger of exploding after they lost their cooling ability.