Satellite images tracked the catastrophic impact of Japan's magnitude-9.0 earthquake and tsunami on the Fukushima nuclear complex and other key sites, and now they're tracking the reconstruction.

To mark Sunday's anniversary of the disaster, DigitalGlobe is releasing pictures showing "before, during and after" views of the devastation. You can see the three views of Fukushima here — but you really should check out our interactive slideshow to get a better sense of the changes that have taken place over the past year at Fukushima and at the Port of Sendai, which was destroyed in the tsunami.

---

"I'm struck by the progress, by how efficient the Japanese have been in reconstructing their infrastructure," Steve Wood, vice president of DigitalGlobe's analysis center, told me today. "In less than a year they've been able to turn this port into an active, functioning component. That's significant, considering that a year ago there were shipping containers, fires and mud covering that entire area. ... And there are literally hundreds of examples of that up and down the coast."

In the hours, days and weeks after the March 11 quake, satellite operators funneled fresh imagery to disaster workers, relief groups, government agencies and private companies coping with the aftermath. "We saw everything from big industrial partners who wanted to see the status of their factories, to government agencies involved in the actual reconstruction," Wood said.

Japanese officials and the U.S. military used the images to figure out which places were best for setting up aid operations, while relief organizations scanned wide-scale maps to see which areas were most in need of help. In places where planes weren't allowed to fly, "we were effectively the only game in town" for that initial post-quake aerial imagery.

Today, satellite images provide an effective way to gauge how much progress is being made, through comparisons of the before-during-and-after views. "To communicate and explain that to people is really an important and powerful tool that I've seen evolve over the years," Wood said. Pictures from space were important in the aftermath of the 2004 Indian Ocean quake and tsunami, they're important for Japan, and they'll be important for current and future hotspots such as Syria.

During Japan's crisis, Wood's team at DigitalGlobe was working 24/7, and the weeks and months have sped by. "It's hard for me to believe it's been a year," Wood said. For some of us, Sunday's anniversary may seem like a turning point — but it's really just one more day in the timeline of Japan's reconstruction. These pictures remind us that the work is far from finished.

More about the Japan quake and tsunami:

• Fukushima wants to know: Is radiation still a threat?
• Japan tourism slowly rebounds year after tsunami
• Slimy, salty, but tasty seaweed revives Japan village
• Tsunami survivors: Obstacles remain for rice farmer
• Tsunami scientists get set for the next wave
• Giant quake like Japan's could hit Pacific Northwest
• Earthquake experts gain predictive powers
• Cook uses recipes to help earthquake survivors heal
• Japan's nuclear plant town remains frozen in time
• Nuke pill frenzy fizzles in U.S. as disaster fades
• PhotoBlog: Panoramic images, then and now
• Japan disaster snarls US nuke plant plans

---

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

 

Last year's earthquake and tsunami was a catastrophe for Japan — but a problem averted for Hawaii and the U.S. West Coast, partly due to luck and partly due to the success of long-range tsunami tracking. Now researchers are working to bring that success closer to home.

If a similar ocean wave were to target the U.S. coastline in the future — and seismologists say that's only a matter of time — the emergency response should be much improved, thanks to the lessons learned from last March's super-tsunami.

"Definitely there are a lot of lessons learned from a big event like that," Vasily Titov, director of the National Oceanic and Atmospheric Administration's Center for Tsunami Research, told me this week.

---

Titov and his colleagues, who are based at the Pacific Marine Environmental Laboratory in Seattle, have focused for years on building better computer models to predict how tsunami waves will spread out from an undersea seismic shock like the one that rocked Japan. Tsunami trackers came in for a good deal of criticism after the 2004 Indian Ocean earthquake and tsunami, which killed an estimated 230,000 people in 12 nations. Since then, government agencies have worked together to fill in the gaps in an oceanwide network of deep-sea and surface-buoy sensors — and the upgrades paid off big time last year.

Readings from a network of more than 50 buoys — including the federal governnment's Deep-ocean Assessment and Reporting of Tsunamis system, or DART —tracked wave heights after a magnitude-9.0 shift in the ocean floor set off a giant wall of water. The waves rose as much as 6 feet in open ocean. "Ten years ago, people would say, 'Oh, it's not possible to have a tsunami that high,'" Titov said. "That was the event that I was hoping not to see in my life."

The computer model correctly predicted the level of flooding that Hawaii would face, seven hours after the earthquake. That provided enough time for a proper evacuation. "Deaths were avoided in Hawaii — I'm pretty confident about that," Titov said.

The model also showed that there'd be only minor impact on the West Coast, due to the fact that the tsunami wave arrived at low tide. "If the West Coast had high tide during tsunami, it would have been much different," Titov said. "There would have been flooding all over the place."

The next wave?
Titov happens to be headquartered in a region that could become ground zero for a future Japan-style tsunami. Studies have indicated that the Cascadia subduction zone, off the coast of Washington state, Oregon and British Columbia, is capable of generating the same kind of ocean wave. In fact, it's thought that such a shock took place off the West Coast more than 300 years ago, setting off a tsunami wave that reached all the way to Japan.

Concerns about the next big wave, wherever it may come, is driving international efforts to track tsunami phenomena closer to the source. Last year's quake and tsunami killed nearly 16,000 people, with many of those deaths coming along the coast. If Japanese authorities had had a quicker assessment of the tsunami threat, they might have launched more intensive evacuation efforts in the first half-hour after the earthquake was detected. Thousands more lives might have been saved.

"That has become the main challenge," Titov told me. "What can be done for this type of event?"

To get a better grip on the local effects of a tsunami, a different kind of monitoring system is needed — a system that has scores of interconnected sea-floor stations, situated close to the source of a potential tsunami shift. The stations would have to be equipped with seismometers and pressure gauges, and send real-time data via satellite links for sophisticated analysis.

Titov and his colleagues think they have come up with a solution to the challenge. "The system we developed worked better than expected," he said. "Detectors can be placed much closer to the source."

Now Japan is making plans to deploy a new $400 million network of 154 sensor stations straddling the Japan Trench, which was the source of last year's seismic shock. That network is due to be put into place in the 2014-2015 time frame. Meanwhile, NOAA is planning to move some of its DART buoys closer to the Cascadia subduction zone and other seismic hot spots.

Simulations suggest that the sensor system and upgraded analysis software can deliver an accurate assessment of local flooding in 30 minutes or less. That might still require authorities to go ahead with pre-emptive evacuations in some areas, even if the initial tsunami alert turns out to be a false alarm. "While the timing is challenging, the situation is manageable," Titov said.

Maintaining the network
At the same time, the existing network of tsunami-tracking buoys needs to be maintained. One of the problems that came to light after the 2004 tsunami was that some of the buoys in the DART network were prone to failure. One critic complained that the tsunami monitoring system was like "a fire alarm that cannot ring."

"The problem is that even that strong array is budgetarily difficult to maintain," Titov said. "That has become the main challenge. We're trying to figure out how to maintain it."

Titov said he found it hard to believe that it's already been a year since that horrible day — March 11, 2011, which is known as "3-11" in Japan. "My heart goes out to all the Japanese," he said. "A lot of our colleagues are from Japan. This has become very personal."

That personal perspective sharpens Titov's desire to develop faster, better ways to predict the paths of the giant waves to come.

"The fact that it's been a year already makes me a little nervous," he told me. "I want to move fast with this research so we're ready for the next tsunami."

More about the Japan quake anniversary:

• Japan-style catastrophe could hit Pacific Northwest
• Earthquake experts upgrade their alert systems
• One year after Fukushima, Japanese town is frozen in time
• Japanese tsunami survivor, 79, looks ahead
• Tsunami Survivors: Struggling to live on, alone
• Japan Red Cross: Whole year wasted after tsunami
• Cosmic Log: Hear the soundtrack of a super-quake
• Nuke pill frenzy fizzles in U.S. as Fukushima fades
• Photo Blog: Panoramic images, then and now
• Japan disaster snarls U.S. nuke plant plans

---

For more about the future of tsunami forecasting, check out Richard Monastersky's report in the journal Nature.

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

One year after Japan's earthquake warning system was put to its sternest real-world test, U.S. researchers have built a system that could provide the same type of advance alerts for quake-prone California — the only problem is that they can't afford to get it ready for prime time.

"I've got a system that works in my office," said Thomas Heaton, director of Caltech's Earthquake Engineering Research Laboratory. "It works for maybe 100 of us who are prototyping the system. It's been a grassroots effort where a number of scientists have cobbled it together as a demonstration project. But to turn it into a system where literally 50 million Americans would have everything linked into it? It's not ready for that."

---

The California network, known as Earthquake Early Warning or ShakeAlert, has been in development since long before the magnitude-9.0 quake and tsunami that swept over Japan last March 11. It operates much like the Japanese network does: Readings from about 400 seismic monitoring stations around California are processed on a real-time basis, and when a quake is detected, computer software figures out how long it will take seismic waves to reach your location.

The system takes advantage of the fact that two types of seismic waves emanate from the epicenter: The first waves to arrive are primary waves, or P waves, which are followed by slower secondary waves, or S waves. The S waves, which travel through Earth's crust at a speed of about 2 miles per second, produce more up-and-down motion and tend to be more damaging. The P waves serve as precursors, enabling experts to estimate the intensity and arrival time for the S waves that will follow.

If the projected intensity is above the level you're worried about, your computer will start sounding an alarm and clicking through a countdown, as seen in the video above.

"Right now it's working as well as you could hope for a kludged-together demonstration project from a bunch of professors," Heaton told me. He can adjust the controls downward to be alerted about minor quakes heading toward Caltech in Pasadena, or turn them up so high he can work undisturbed in his office.

"You can go days without anything, and then a day comes when there's a cluster," he said.

The Japanese system, which was developed at an estimated cost of $500 million, turned in a stellar performance during last year's quake. As the video below demonstrates, Tokyo residents had as much as 30 seconds' warning before the shaking began.

Thirty seconds may not sound like much warning, but it's enough time to shut off gas mains and issue a warning to take cover. In Japan, the warnings are flashed via radio and TV, as well as through computer links and mobile phones. Automated broadcast alerts can be set to turn on a car's emergency flashers and warn drivers to slow down and pull over. The same principle is applied to safeguarding Japan's extensive rail system: Thanks to automated warnings, two dozen trains that were operating in the earthquake zone on March 11 were brought to a halt within seconds, with no reports of serious injuries or damage.

Bugs in the system
During last year's catastrophe, the biggest problem had to do with the fact that the closer residents were to the quake's epicenter, the less warning they received. Another issue was that the complexity of the initial seismic shock and the aftershocks caused the  system to become overloaded, leading to a temporary shutdown.

Heaton and his colleagues are encountering similar bugs in the California system. "They're always being engineered to be better systems and less buggy, but we'll never eliminate all the bugs," he said. Right now, the team is working on an Android app version of ShakeAlert. Even the app would be unsuitable for mass distribution, however.

"The technology exists to deploy it, but strategically, I don't see how we could ever support it," Heaton said.

Going public with ShakeAlert would require a more concerted effort, backed by the expertise and funds that are typically associated with federal government agencies such as the U.S. Geological Survey. So far, the USGS has spent about $2 million on ShakeAlert, and the Gordon and Betty Moore Foundation is backing the research with $6 million in contributions to Caltech, the University of California at Berkeley and the University of Washington over the next three years. Other supporters include Google.org and Deutsche Telekom's Silicon Valley Innovation Center.

The California Integrated Seismic Network estimates that a statewide quake warning system would cost about $80 million over five years, while the cost of a similar system for the Pacific Northwest has been estimated at $70 million. But it might take additional funding to get the system as fully linked in with society as Japan's system is now.

"Ultimately, when it does run, you don't want university professors running it," Heaton said, with a tone of amiable self-deprecation. "We're the least reliable people to run something like that."

Realistically, will ShakeAlert ever be ready for prime time? Heaton thinks it might take more than a catastrophic earthquake on the other side of the world to get Americans motivated about earthquake alerts at home.

"My experience at this point in my life is that it's hard to get people to focus on things like this unless something bad happens," he said. "It's been really peaceful and quiet in the western U.S. for quite some time now. ... We're very concentrated on our own issues. We were shocked by what happened [in Japan], but not enough to actually do something."

Longer-range prediction?
If it's hard to put in a system based on well-tested geophysics that provides a warning just seconds in advance of the Big One, it's a lot harder to extend the lead time to hours, or days. But people keep trying.

"One prediction that we have learned to make following earthquakes, and this one is a very strong prediction, is that several people will claim to have predicted the earthquake," Heaton joked.

Some researchers are trying to determine whether a statistical analysis of earthquake clustering can lead to better assessments of the chances that a big earthquake will follow smaller tremors. This month's issue of Physics World looks into the prospects for short-term probabilistic forecasting, as well as the controversy surrounding the researchers who didn't predict the deadly 2009 L'Aquila earthquake in Italy (and are now facing manslaughter charges).

Heaton is doubtful that statistics could ever predict the onset of future quakes with the kind of reliability people expect. He noted that 50 percent of all earthquakes have foreshocks, and one quake out of 20 turns out to be a foreshock for a larger quake. "We can say, yeah, earthquakes come in clumps, but to get more particular and specific — personally, I don't think it's very helpful," he said. "What are people going to do with that information, anyway?"

It's possible that some as-yet-unknown mechanism might provide advance indications that a big quake is coming. "There are interesting observations that seem to be reliable about phenomena that are totally mysterious to us," Heaton acknowledged. "Many of them concern electrical phenomena."

Heaton even keeps an open mind about claims that animal behavior can be analyzed to predict future earthquakes.

"I think we know some things that animals are unlikely to do — that is, pick up vibrations from the earth," he told me. "There may be other things out there that are happening that we don't understand very well. So I'm not going to say 'never' to something like that. But the more we think about the problem, the more we recognize that once an earthquake starts, at some point, trying to predict how big it will get before it stops seems to be a particularly difficult dynamics problem."

More about the Japan quake anniversary:

• One year after Fukushima, Japanese town is frozen in time
• Japanese tsunami survivor, 79, looks ahead
• Tsunami Survivors: Struggling to live on, alone
• Japan Red Cross: Whole year wasted after tsunami
• Cosmic Log: Hear the soundtrack of a super-quake
• Nuke pill frenzy fizzles in U.S. as Fukushima fades
• Photo Blog: Panoramic images, then and now
• Japan disaster snarls U.S. nuke plant plans

---

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Researchers from Georgia Tech suggest that the best way to visualize the seismic effects of last year's Japan earthquake is with your ears — and they've put together three "audifications" to demonstrate.

One recording is based on seismometer readings taken on March 11, 2011, along the Japanese coastline between Tokyo and the hard-hit Fukushima nuclear complex. The audio starts with a bang — the magnitude-9.0 shock — and continues with the pounding noise of aftershocks that sound like a bull knocking over shelves in a china shop.

---

Readings from seismometers that were place about 90 miles away from the quake's epicenter reveal a double-barreled bang. That suggests there were "at least two patches of high-frequency radiation from the mainshock rupture," the researchers note.

A third clip is based on readings from California. The Japan quake sparked deep rumblings in the San Andreas Fault, which begin with a sound like distant thunder, and then continue with a crackle that represents "induced tremor activity at the fault," the Georgia Tech team says.

The audio was created by taking the seismic signals, which are typically detected in the 0.01 to 100 Hz frequency range, and speeding the soundtrack by a factor of 50 to 100 times. That brings the sound into the audible range of 20 Hz to 20 kHz, and crunches hours' worth of data into less than a minute of audio.

In these YouTube videos, the seismic data is also displayed on a graph.

"By combining seismic auditory and visual information, static 'snapshots' of earthquake data come to life," Georgia Tech's Zhigang Peng and his colleagues write in the March-April edition of Seismological Research Letters. "In addition, this approach allows the audience to relate seismic signals generated by earthquakes to familiar sounds such as thunder, popcorn popping, rattlesnakes, gunshots, firecrackers, etc."

The researchers say that seismic audifications can make it easier to explain the concept of distant quake triggering to general audiences, and that they also provide a tool for experts to identify and understand such seismic signals in other regions. What do you think? Do these clips give you a better feel for how seismic events get started and keep rattling on?

One year after the disaster in Japan:

• Then and now: The 2011 Japan tsunami
• Kuni Takahashi revisits the earthquake zone
• Ridley Scott and Japan TV team up on documentary
• Midway Atoll expecting Japan tsunami debris soon

---

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

The depths of Africa's Lake Kivu harbor untold quantities of carbon dioxide and methane gases that could provide abundant electricity to millions of Rwandans and Congolese settling along its shores. But those gases could suddenly release, killing everything in and around the lake.

"Understanding whether you can find scenarios that would lead to something like that, a catastrophic release of gas, is of course important," Anthony Vodacek, a remote sensing scientist at the Rochester Institute of Technology in New York, told me on Monday.

---

He is leading a two-year survey that aims, for the first time, to provide a scientific portrait of the entire lake system. The team consists of seismologists, biologists, remote sensing specialists, and other scientists who will combine their areas of expertise to provide a baseline understanding of the system.

"If you don't know what the starting point is, you don't know what the change is. And so that is part of what we'd like to establish here," Vodacek said.

Methane extraction
The Rwandan government has already built a power plant along the lake's shores which siphons methane from the depths of the lake to generate 3.6 megawatts of electricity, about 4 percent of the country's needs. The aim, eventually, is to generate several hundred megawatts.

Lake Kivu is one three known so-called explosive lakes in the world. The other two are in Cameroon. Lake Nyos experienced an explosive eruption in 1986 that killed 1,500 people. During these so-called overturning scenarios, something triggers the gases trapped in the depths to burst towards the surface.

The gas is trapped at the bottom of the lake because the streams that feed the lake are slightly brackish. Salty water is denser than freshwater and so, it sinks to the bottom, taking all the organic detritus with it that releases carbon dioxide as it decomposes.

In addition, the lake is in a seismically active region. "It is a rift valley lake," Vodacek noted. "The Africa continent is pulling apart … and that means there are fault lines, there are earthquakes, and those can be tied in to potential triggers for what goes with the lake overturning."

It's possible that people extracting the gases to generate electricity will stave off a catastrophic overturning of the lake, though it could also upset the stability of the lake, Vodacek noted. That's one of the questions the team wants answered.

Extraction of the methane to generate electricity could be a huge benefit for development in the region, Vodacek noted. Currently, most of the cooking fuel comes from forests around the lake, the same forests that are home to endangered mountain gorillas.

"Normally, you don't think of development as having positive impacts, but in this you could because it could turn people away from cutting down the forest and subsistence farming on these steep hillsides in the region," he said.

If the lake becomes a source of fuel, then conservationists can focus reforestation efforts in the surrounding hills and help protect the gorillas, Vodacek added.

Explosive history
Team member Robert Hecky, an aquatic biologist at the University of Minnesota, Duluth, performed an analysis of a sediment core from Lake Kivu in the 1970s and found evidence for catastrophic overturns about once every 1,000 years beginning about 5,500 years ago.

This finding corresponds with genetic evidence from cichlids, freshwater fish that first evolved in the lake. Today, only about 15 species are found in the lake, though thousands more species are in other lakes.

People looking at the molecular clock of these fish put two and two together and realized the Lake Kivu fish experienced an extinction about 5,000 years ago, "which coincides with the analysis of the sediment and the overturning of the lake," Vodacek said.

Hecky and other team members will bring advances in the study of lake sediment cores to refine the timeline of the overturning events and perhaps gain insight to the triggers such as landslides or volcanic activity.

Seismologists on the team will embrace advances in GPS sensors to get a detailed read on the rifting process in the valley to understand where fractures and fault lines are located.

Vodacek, who is leading the effort, will take a view from the sky to piece all the data together.

In particular, he is embracing recently released data sets of satellite imagery from NASA that provides nearly 40 years worth of data on the region, showing how the landscape has changed as people settled on the lakeshore and cut down the forests.

"You're always hearing these horror stories of natural resource development without any regard to the environmental impacts of that," he said. "Here's a case where we would like to go in and make sure there's necessary due diligence to make sure that things aren't destroyed as a resource is developed."

More on Africa energy and conservation

• Rwanda harnesses energy from exploding lake
• Deal struck to protect Congo mountain gorillas
• Scientists say eruption in Congo imminent
• Scientists: Inbreeding helps African fish

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

 

 

Earthquakes don't kill people, poorly built buildings do. The problem is that most disaster-proof, inexpensive housing technologies don't fit the cultural preferences of the communities that need them, according to a non-profit that's promoting a fix.

"This is something that we can control and we can change if we know how to do it correctly," Elizabeth Hausler, the CEO and founder of Build Change, which has led post-disaster reconstruction efforts in China, Haiti, and Indonesia, told me last week.

Implementation of simple engineering principles using locally-available materials and labor can lead to culturally-acceptable housing that can survive the violent shaking of earthquakes and hurricane-force winds.

---

"Our mission is to reduce deaths and injuries from earthquakes when houses collapse, but there are so many financial and social features to that," Hausler said. "You've got to get the architecture right; it has to be appropriate for the climate and the culture."

The approach contrasts with government and relief agency programs that rebuild communities with disaster-proof homes, such as sturdy geodesic domes, that don't fit in with the aesthetic or culture of the local community. As a result, the building technology isn't replicated after the help leaves town.

"You completely miss the opportunity to train people to build something that they are familiar with … to improve on their preferred way of living," Hausler said.

The three Cs
The trick, she's found, is to teach local communities what she calls the three Cs of disaster proofing: configuration, connections, and construction quality. 

Configuration relates to paying attention to a home's design plan and layout – keeping an eye out for things such as load-bearing walls in each direction of the home to improve durability and lightweight roofs.

"In an earthquake, you don’t want a heavy roof, you don't want something heavy over your head," Hausler noted, adding the caveat that a lightweight roof in a hurricane-prone region needs to be tied down so it won't blow away.

Another configuration to consider is the placement of windows and doors. These openings weaken the structural integrity of a wall that holds up the roof, but in a many regions of the world lots of open windows and doors are needed for climate control.

Instead of saying only small windows are acceptable, Build Change promotes putting reinforcements in place.

The second C, connections, focuses on the engineering principle that everything has be connected together to perform well in an earthquake or hurricane, Hausler explained. Walls connected to the foundation, roof connected to the walls, etc.

The third C, construction quality, is about finding locally available building materials and qualified labor to do the job. That means laying bricks so that there's enough mortar in the spaces in between, for example, or soaking bricks in water before building a wall to improve its strength.

Empowered stakeholders
Implementation of the three Cs is already standard practice in some parts of the world, including Japan, which was recently struck by a powerful earthquake and tsunami. As a result, Hausler's organization isn't planning to work there. 

"Japan has some of the best engineers in the world and with some excellent building codes, so we really wouldn't add a lot of value there," she explained.

"We add more value in a place like Haiti or a rural area in China where there really is a dearth of trained professionals and engineers who understand and enforce a simple building code."

By working in disaster-prone regions that currently lack the engineering expertise to build sturdy homes with limited funding, Build Change hopes to empower local homeowners and builders to continue implementing the three Cs long after the organization leaves town.

"That is the true test of sustainability," Hausler said. "That is our ultimate goal: that people continue to build earthquake resistant houses on their own without us and without any financial subsidy."

Hausler was awarded the $100,000 Lemelson-MIT Award for Sustainability on May 10 in recognition of her engineering accomplishments and creation of a model that establishes sustainable earthquake resistant housing in the developing world.

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Vesuvius, the Italian volcano that famously erupted in AD 79 and destroyed Pompeii, may awaken sometime in the future with even more catastrophic results, according to some experts who consider the volcano the most dangerous in the world.

The prospect, which could spell disaster for nearby Naples, a metropolis of 3 million people, is stirring up a vigorous debate among scientists and civil authorities on how to prepare, journalist Katherine Barnes reports for Nature News. 

---

Part of the debate centers on the risk and scale of future eruptions. Some studies suggest the volcano is capable of massive eruptions, such as one some 3,800 years ago that triggered pyroclastic flows that buried Naples under 12 feet of ash and debris.

Other scientists argue that the eruptive nature of Vesuvius has changed over time and that smaller eruptions akin to one in 1631 are more the norm. That one killed 6,000 people but affected a much smaller area.

The course of disaster preparation planning depends on which scenario civil authorities choose as their basis. The worst case scenario would mean evacuating 3 million people from Naples. Other scenarios would delay such a complicated evacuation unless prevailing winds shifted and put it in harm's way.

"It's an extremely complex problem to solve," Augusto Neri at the National Institute for Geophysics and Volcanology's lab in Pisa told Nature News. "We simply do not know how the volcano works." 

Barnes notes that the type of debate swirling around the potential catastrophic Vesuvius eruption is becoming more common in the wake of the earthquake and tsunami in Japan. These types of disasters, called black swans, are unlikely but potentially devastating.

Another example is how to prepare for a potential devastating quake along the Cascadia subduction zone along the west coast of North America. There, experts say, the science pointing to a future earthquake and tsunami is clear, but planning for it is lagging behind.

More stories on Mount Vesuvius:

• Experts say heat, not suffocation, killed Mount Vesuvius' victims
• Pompeii family's final hours reconstructed 
• Ancient quake raises risk for modern Naples 
• Eight dangerous volcanoes around the world

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook pageor following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Underwater robots equipped with imaging sensors that can see through murky waters are at work inspecting bridges, docks, and pipelines in port areas of the earthquake- and tsunami-ravaged coastline of Japan.

The robots, between the size of a suitcase and football, join other robots inspecting the crippled nuclear reactors at the Fukushima Dai-ichi plant. On Monday, those robots reported that radiation levels are too high for human repair crews.

---

Robin Murphy, director of the Center for Robot-Assisted Search and Rescue at Texas A&M University, in College Station, and one of the world's top experts in rescue robotics, told me in the days after the disaster that underwater robots could also be of use in Japan. All she needed was an official invitation. 

Port deployment
That invitation came and her team, in partnership with Tetsuya Kimura of the Nagaoka University of Technology, deployed the robots Tuesday at the fishing port Minami-sanriku-choy to look for debris and other threats in the cloudy waters that could block passage of fishing boats, which need at least 15 feet of clearance before they can return to work.

On Wednesday, Murphy reported that the port was clear of obstructing debris, and that the robots "performed admirably."

"We were surprised at the lack of cars and other big objects underwater. The lower portions of the town is one rumbled mass of cars, piers, metal pilings, and such all twisted about, so we expected to see at least some of the same in the water," she  wrote in a blog post from the field. 

The team primarily encountered anchor stones and ropes used in the harbor and some smaller bits of debris. The lesson learned, Murphy notes, is a need for simulation software that predicts where debris goes in the wake of a tsunami or hurricane. 

No bodies of victims were found, which Murphy said is bittersweet. Minami-sanriku-choy had a population of 20,000. An estimated 2,000 people are dead or missing following the disaster. 

Similar to BP effort
The robots in use are smaller versions of the types used during the BP oil spill. They include the suitcase-sized Seamor, which can spot objects of interest with sonar capabilities and Seabotix's SARbot, which can zero in on the objects.

Other equipment in the team's arsenal includes the football-sized AC-ROV robot and monitoring equipment for AEOS Inc. All of the robots have a tether to allow operators on the surface to control the vehicles in real-time and watch the sonar and video footage. 

The team is now moving to Rikuzen-Takada to continue the search-and-rescue efforts. Murphy will update her blog as time permits.

Red Whittaker, a robotics expert at the Carnegie Mellon Robotics Institute, told me in March to expect robot deployments that help Japan recover from the earthquake and tsunami to last for weeks, months, and years.

"These are campaigns, not skirmishes, and typically new tools are brought to bear as the challenges arise and those challenges are very different over time," he said.

More coverage on robots in Japan:

• Robots en route to Japan 
• Robots to the rescue in Japan?
• Robots gauge radiation near Japan plants
• Japan plans to send robot to the moon by 2015

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

First there was the earthquake and tsunami in Sumatra in 2004. Chile was shaken and lashed violently a year ago. Japan is still reeling from the twin disasters on March 11. It seems as if the Earth has woken from a long slumber and is violently re-jiggering its plates. Is there any truth to the notion?

The question of megaquake clustering, which I explored in the days following the 9.0 earthquake and tsunami in Japan, was a hot topic of conversation Thursday at the Seismological Society of America's annual meeting in Memphis, Tenn., according to various media reports.

---

There, Charles Bufe, a seismologist retired from the U.S. Geological Survey in Denver, said the spate of recent megaquakes is very similar to a string of seven magnitude 8.5 or greater quakes that struck between 1950 and 1965. The intervening decades, he noted, were quiet.

Bufe and USGS colleague David Perkins analyzed the clustering and concluded that it's unlikely just random. "It's very statistically significant," Bufe said, according to the Seattle Times. "We think we're in an increased hazard situation for these very large earthquakes."

According to their calculation, there's a 63 percent chance that another magnitude 9 or greater quake will strike somewhere in the world within the next six years. If these megaquakes are random, the chance is about 24 percent.

Other experts at the meeting, however, supported the notion that what seems like a clustering of megaquakes is really just random, except for clusters of aftershocks in the vicinity of the major rupture, such as those continuing in Japan.

For example, seismologist Andrew Michael, who's with the USGS in Menlo Park, Calif., announced at the meeting that he's examined databases for evidence of clustering and, as he told me in an email in March, found "there is no evidence of global large-earthquake clustering."

That said, scientists are far from being able to predict earthquakes and acknowledge there is much to learn about them. It's possible that entrenched ideas will be proven wrong, said Rick Aster (outgoing president of the seismological society), encouraging scientists to keep asking questions.

More stories on earthquake science:

• 8.7 ideas in earthquake prediction
• What causes earthquakes?
• Pacific Northwest at risk for mega earthquake 
• Is Japan's quake part of a cluster? 
• Japan's aftershocks are not shocking 

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

 

The news today that Japan was hit by a magnitude 7.1 aftershock nearly a month after a magnitude 9.0 earthquake and tsunami devastated the northeast coast is grim, but not shocking to experts.

"It is not surprising as part of the aftershock sequence to see a magnitude 7 plus," John Bellini a geophysicist with the U.S. Geological Survey told me today.

---

Generally, he said, for each lower magnitude you expect to see ten times the preceding magnitude. So, in this case, experts expect to see one magnitude 8 earthquake, up to 10 magnitude 7s, and many, many 6s, 5s, and 4s. 

Hundreds of aftershocks
Indeed, hundreds of aftershocks have hit Japan since the March 11 earthquake, but few have been above 7.0. According to the USGS, an aftershock about 30 minutes after the main shock was a 7.9. There has been one other greater than 7.0 aftershock and many smaller ones. An 8 is still possible.

"You can still have it," Bellini said, "but as time goes by it is less and less likely each day and we would expect to see fewer 7s and fewer 6s." In fact, he added, "we've been seeing a lot less aftershocks for the last week than two weeks ago."

John Rundle, an expert on earthquake dynamics at the University of California at Davis, said a large aftershock, especially near a major city such as Tokyo, was among his largest worries when we spoke about earthquake clustering last month.

More to come?
The 7.9 aftershock about 30 minutes after the main shock, which was about 100 kilometers from Tokyo, could have been the 8 he was worried about, he told me today, but he doesn't think the city is in the clear.

"Tokyo has had a lot of seismic activity in the last month," he said. "The thing I worry about is one of those events being significantly larger than the ones they've been having."

New to his list of worries based on probability analysis is the southwestern Japan town of Nagasaki, which he says "has an elevated probability for a magnitude 7 earthquake in the next 12 months or so because it's had two magnitude 7s in 1968 and since the last one it has had about 10 magnitude 6s. So it would be about for a magnitude 7."

More on Japan earthquakes:

• Is Japan's quake part of a cluster?
• Vast devastation, search for survivors after Japan quake
• Photoblog: How the quake shifted Japan
• Japan earthquake aftershocks

 

---

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).