The Caldera of Santorini is today a ring of islands in the Aegean. Photograph by Flickr member EmreKanik.

A caldera is a very large crater that forms after a very large volcanic eruption. The eruption is explosive and ejects a lot of material. Most of what comes out of the volcano is blown a great distance into the atmosphere and over a large area, so a huge volume of the local landscape is simply gone—thus the large crater.

Many people know about the Yellowstone Caldera because it is the location of a lot of interesting ongoing thermal and volcanic activity, some of which has been in the news lately, and it has even been featured in a recent epic disaster fiction film called 2012 in which the re-explosion of the Yellowstone Caldera is only one problem of many faced by the film’s heroes and heroines.

Somewhat less known but still famous is the Santorini Caldera. It is in the Aegean Sea, in Greece, near the island of Crete. Santorini blew about 1,600 B.C. and seems to have caused the end of the Minoan Civilization; the edge of the volcano’s caldera is now a ring of islands. By comparison with Yellowstone, Santorini is small. The Yellowstone Caldera is about 55 by 72 kilometers in size, while Santorini’s is about 7 by 12 kilometers.

Santorini is the subject of an investigation just reported in the journal Nature. The volcano has blown numerous times in the past. The investigation shows that the last explosion, the one at about 1,600 B.C., was preceded by a stunningly short period of build-up of underground magma. It seems as though the magma, enough for a very large eruption, moved into the zone beneath the caldera in two or more events less than 100 years prior to the explosion, with a significant amount of the magma moving into place just a few years before the blast.

If we go back a decade or so, volcanologists thought that the buildup to a major eruption like this would take more time, perhaps many centuries. Various lines of evidence have caused scientists to start to think that the buildup to blast-time might be shorter than that, and the present report is an excellent direct measurement of the timing which seems to confirm these growing suspicions.

How can scientists tell that it happened this way? Using volcano forensics, of course! Here’s the basic idea:

When shocking events happen, such as the intrusion of a bunch of magma into an area of rock, or associated seismic activities, the various chemicals in magma become “zoned.” Waves of energy passing through the molten rock cause bands of specific types of chemicals to form. During a period of no shocks, if the temperature is high enough, these bands dissipate. Some bands dissipate in very short periods of time, others over very long periods of time. If at any point the magma is released in a volcanic explosion such as the type that forms a caldera, the material suddenly cools and the state of the bands, dissipated to a certain degree, is preserved. Later, sometimes thousands of years later, geologists can study the rocks and estimate the amount of time between shock event and the volcanic explosion by measuring how much dissipation has occurred. It is a sort of magma-based clock.

In the case of Santorini, everything seems to have happened well within a century. This formation of a magma chamber large enough to cause a major eruption occurred after an 18,000-year-long dormant period. So, if we were thinking that the long period of time between caldera eruptions was characterized by a slow and steady buildup of magma, we were probably wrong. The real significance of this is that we can’t look at a caldera that is known to have erupted multiple times and rule out a future eruption simply on the basis of a low level of current activity. And of course, we are left wondering what initiates this rather rapid recharge of the magma underneath a caldera.

It’s a good thing that scientists are studying and monitoring these volcanoes!

Druitt, T., Costa, F., Deloule, E., Dungan, M., & Scaillet, B. (2012). Decadal to monthly timescales of magma transfer and reservoir growth at a caldera volcano Nature, 482 (7383), 77-80 DOI: 10.1038/nature10706

Some scientists have suggested the weight of water in the lake created by the Zipingpu Dam in China triggered the 2008 Sichuan earthquake (courtesy of flickr user TaylorMiles)

On Saturday, a magnitude 4.0 earthquake shook eastern Ohio, a week after a smaller temblor in the region worried officials so badly that they halted work on a fluid-injection well in Youngstown.

This wasn’t the first case in which the injection of fluids into the earth has been linked with earthquakes. In April, for example, the English seaside resort town of Blackpool shook from a magnitude 2.3 earthquake, one of several quakes now known to have been caused by hydraulic fracturing (or “fracking,” which involves pumping large amounts of fluid into the ground to release natural gas) in the area. The link has been known for decades—a series of quakes in the Denver, Colorado, region in 1967 was caused by fluid injection.

The phenomenon is so well known that Arthur McGarr, a geologist at the U.S. Geological Survey in Menlo Park, California, has developed a method to predict the highest magnitude of an earthquake that could be produced by hydraulic fracturing, carbon sequestration, geothermal power generation or any method that involves injecting fluid deep into the earth. Though the method doesn’t allow scientists to predict the likelihood that such a quake would occur, it will let engineers better plan for worst-case scenarios, McGarr told Nature.

Hydraulic fracturing naturally causes small tremors, but bigger quakes may occur if the liquid migrates beyond the area where it’s injected. The New York Times reports:

The larger earthquakes near Blackpool were thought to be caused the same way that quakes could be set off from disposal wells—by migration of the fluid into rock formations below the shale. Seismologists say that these deeper, older rocks, collectively referred to as the “basement,” are littered with faults that, although under stress, have reached equilibrium over hundreds of millions of years.

“There are plenty of faults,” said Leonardo Seeber, a seismologist with the Lamont-Doherty Earth Observatory. “Conservatively, one should assume that no matter where you drill, the basement is going to have faults that could rupture.”

Earthquakes caused by fracking are of particular interest right now because the number of wells, particularly in the United States, has been skyrocketing (along with reports of nasty environmental consequences, such as flammable water). But this is only one way that humans are causing the earth to quake. Mining (taking weight from the earth), creating lakes with dams (adding weight on top of the earth) and extracting oil and gas from the earth have caused at least 200 earthquakes in the last 160 years, Columbia University earthquake scientist Christian Klose told Popular Science.

Klose’s research has demonstrated that coal mining was responsible for Australia’s most damaging earthquake in recent memory, the magnitude 5.6 Newcastle earthquake of 1989. And in 2009, he was one of several scientists who suggested that the magnitude 7.9 earthquake in China’s Sichuan Province in 2008, which left 80,000 dead, could have have been triggered by the Zipingpu Dam. (That wasn’t the first time a dam was linked to an earthquake—Hoover Dam shook frequently as Lake Mead filled.)

It can be easy to look at our planet and think we’re too small to really do much damage, but the damage we can do can have severe consequences for ourselves. ”In the past, people never thought that human activity could have such a big impact,” Klose told Wired, “but it can.”

Cats and earthquakes were popular subjects this year. (image courtesy of flickr user 37prime)

It’s that time of year when journalists and bloggers put together their reviews of the past 12 months. But the list below is unlike any other. You may have noticed that Surprising Science tends to cover science a bit differently than other blogs and publications do. Combine that with a diverse (and, of course, fabulous) readership, and you’ve got an interesting list of most-read stories for the year. (If you’re looking for a more traditional 2011 retrospective, we recommend the lists from Discover, Scientific American and Science.)

#10 Earthquake in Washington, D.C.: On August 23, the Smithsonian offices, along with a good portion of the Northeast, shook due to a magnitude 5.8 earthquake in Mineral, Virginia. In a weird coincidence, I had been researching earthquakes in unexpected places when the quake took place, and so people in my office jokingly blamed me for the incident.

#9 14 Fun Facts About Chickens: Following the earthquake and Hurricane Irene, we took a break from natural disasters with weird chicken facts. My favorite? That a female bird can eject the sperm of a rooster if she decides she doesn’t want his chicks.

#8 The Science Behind the Japanese Earthquake: On the morning of March 11, we woke up to news of a powerful earthquake off the coast of Japan. That shaking, however, would soon be overshadowed by the devastating tsunami and nuclear disaster that followed.

#7 Examining Telecommuting the Scientific Way: Unfortunately this post did not have the result I’d hoped, and I’m still not allowed to telecommute. (But if anyone has been successful in using these arguments, please let us know in the comments below.)

#6 The Secret Lives of Feral Cats: After a study in which scientists tracked feral kitties, we weighed in on the question of whether it was better to trap the cats, spay/neuter them and release them back into the wild or, as some advocate, euthanize any found. The blog came down on the side of catch and release, but we discovered many readers who have a serious hatred for these felines.

#5 The Curious World of Zombie Science: We examined an interesting trend in science, the study of human zombies, including computer models of the spread of the zombie disease, potential ways zombies could be created and how math could save you from a zombie attack.

#4 The Myth of the Frozen Jeans: Levi’s and the New York Times claimed that freezing your jeans would kill the germs that make them smell. Scientists who study bacteria disagree.

#3 Five Historic Female Mathematicians You Should Know: Our list, a companion to a top ten list of historic female scientists, included the creator of the world’s first computer program and a contemporary of Albert Einstein.

#2 Life Without Left Turns: A study that found that intersections constructed to eliminate dangerous left turns were more efficient than traditional intersections added to my convictions that getting rid of left turns would be a good thing. But not all my readers agreed.

And #1 The Glow-in-The-Dark Kitty: A story about Mayo Clinic researchers who created a fluorescing cat as part of their studies on feline HIV, which they hope would lead to insight on human HIV and AIDS, sparked a debate in the comments about the ethics of the research.

A map of extreme weather events in the United States, January to October 2011 (credit: NRDC)

The United States may not have seen anything like Hurricane Katrina this year, but it’s been a bad year for extreme weather events nonetheless. High heat, drought and wildfires in Texas. Flooding in the Midwest and Northeast. Deadly tornadoes. The Natural Resources Defense Council found nearly 3,000 broken weather records throughout the United States, and that count went only through the end of October. A map compiling the locations of these events is above; an interactive version that lets you visualize the events through time can be found on the NRDC website.

Scientists are reluctant to say any specific weather event is the result of climate change (weather and climate are, after all, not interchangeable). But they do largely agree that extreme weather events, such as the ones we’ve seen this year, will become more and more common because of climate change.

And those events come with a price. NRDC provided an estimate of $53 billion associated with the events in the group’s tally–if climate change contributed even a fraction to these events, we’re looking at potentially billions of dollars lost. And a country climbing out of a recession could surely use that money elsewhere.

What will humankind do about this? Well, 15,000 delegates are currently meeting in Durban, South Africa, to discuss just that, but little is expected to come out of the meeting. Christie Aschwanden at The Last Word on Nothing thinks part of the reason for current inaction is how we look at the whole situation:

The problem can seem insurmountable, and it’s possible that it is—not because there is no solution, but because we are incapable of choosing it. There’s a one-word solution to the climate (and energy) problem staring us in the face—restraint. Simply consuming less. It’s too late to talk about carbon emissions. With a population catapulting toward nine billion or more, it’s time to focus on carbon omissions.

Restraint is not the easy, no-need-to-change-a-thing solution that people keep pretending we will find. But it’s a reality-based solution that will happen whether we want it to or not. We can plan for it and make the hard choices ourselves, or we can wait for them to be forced upon us. Using less doesn’t necessarily mean lowering our quality of life, it means redefining how we measure our wellbeing.

I’m not sure “restraint” will be any easier of a message to sell to a global population, and particularly a U.S. population, than “reducing carbon emissions,” but it’s an interesting way to look at the problem. If the old ideas aren’t working, we need new ones.

So here’s the challenge: How should we go about addressing climate change? Are global agreements worth the time, energy and carbon emissions it takes to make them? Do small changes made in your own home make any difference? If you were in charge, what would you do? I’m really hoping that one of you has a good answer (tell us in the comments below), because these extreme weather events are taking a toll and humans need to do something to prevent the worst from happening.

A nearly dry horseshoe lake at Brazos Bend State Park, Texas (photo by Sarah Zielinski)

“What is this, rain? I was promised a drought,” I joked to a friend as we drove through ten seconds of drizzle this weekend in Houston. I needn’t have worried–the rest of the day was sunny and warm. It was a pleasant diversion from the cooler temperatures of a mid-Atlantic fall, but in Texas, warm and dry has become a real worry. The entire state is in the midst of an exceptionally bad drought, as you’ve probably read in the news. But what does that look like on the ground?

In Houston itself, there isn’t too much evidence of the drought. Sure, the lawns and plants may look a little brown in places, and there’s the occasional sign notifying people of watering restrictions. But if your vision of drought is wildfires or the Sahara Desert, you’re bound to be disappointed.

An alligator suns itself on the edge of Elm Lake (photo by Sarah Zielinski)

Even outside the city things don’t seem so bad at first glance. It’s a bit dusty, and the cows are munching on bits of grass in rather brown fields. When we started walking around Brazos Bend State Park, however, the drought quickly made itself known. One horseshoe lake had water and made a nice home for several alligators, but the other was full of dead vegetation and had only one tiny little patch of water, barely suitable for small birds looking for a drink. The park’s largest body of water, Elm Lake, which appears as a large patch of blue on a map of hiking trails, had shrunk around the edges and the shallow water was often covered in a nasty green algae. On the bright side, the alligators clustered near the water along the edge of the lake, which made them easy for us to find.

The effects of a drought come in ways we often don’t expect. Migrating birds will be fewer in Texas this year, and they’ll have fewer places to stop. That will give hunters fewer opportunities to pursue their hobby. Migrating monarch butterflies will find it more difficult to cross the state on their way to Mexico; they’ve already had a bad year, dealing with the drought in the spring and a cooler summer around the Great Lakes. Cattle ranchers have sold off parts of their herds; with grass and water scarce, and importing hay from other states expensive, they can’t afford to keep so many animals. The price of beef, and other foodstuffs, will likely rise. Even drought-tolerant plants are not immune from a drought this bad. Power generation, heavily dependent on water, could take a hit. Communities are opposing new projects that would use up the little water available.

The last 12 months have been the driest since record-keeping began in 1895. And a few inches of rain will do little to alleviate the precipitation backlog (26 inches in Central Texas). But Texas, even the United States, isn’t alone in this problem. Climate change will likely bring more droughts around the world. As I reported last year in Smithsonian:

Other regions—the Mediterranean, southern Africa, parts of South America and Asia—also face fresh-water shortages, perhaps outright crises. In the Andes Mountains of South America, glaciers are melting so quickly that millions of people in Peru, Bolivia and Ecuador are expected to lose a major source of fresh water by 2020. In southwestern Australia, which is in the midst of its worst drought in 750 years, fresh water is so scarce the city of Perth is building plants to remove the salt from seawater. More than one billion people around the world now live in water-stressed regions, according to the World Health Organization, a number that is expected to double by 2050, when an estimated nine billion people will inhabit the planet.

“There’s not enough fresh water to handle nine billion people at current consumption levels,” says Patricia Mulroy, a board member of the Colorado-based Water Research Foundation, which promotes the development of safe, affordable drinking water worldwide. People need a “fundamental, cultural attitude change about water supply in the Southwest,” she adds. “It’s not abundant, it’s not reliable, it’s not going to always be there.”

Water, either too much or too little, is one of the biggest problems we can blame on climate change. At least in places like the United States and Australia, there is enough money for a drought to be no more than an inconvenience. In other parts of the world, however, water problems are going to end in human deaths.

A storm rolls in above Bangkok (courtesy of flickr user Dennis Wong)

I’m kind of obsessed with weather. There’s a practical side to this—I don’t own a car and getting caught in a rain or snow storm can be a problem—but I also a have quite a bit of awe for the power of nature. I once lived on the edge of Tornado Alley, and I’ve experienced ice storms, torrential downpours, high winds, blizzards and hurricanes. I always keep an eye on the weather and have a plan when something bad is predicted or formulate a plan when something bad starts to happen. But I’m realizing that I may be in the minority.

Back in January, a huge ice storm headed towards Washington, D.C. A local weather blog recommended people be off the streets by 4 p.m., but few heeded the warning. They headed out as the ice started to fall and it took some people eight hours or more to get home. If they made it at all.

When a hurricane heads towards land, some people call the local television station to ask if they should be boarding up their houses. And they get angry when the forecast turns out to be wrong, which can easily happen even with all of our modern prediction tools. That is understandable when a storm turns out to be worse than expected, but it can also be dangerous when it goes the other way. How many people who evacuated from New York City prior to Hurricane Irene, which didn’t bring as much flooding to the area as had been predicted, will heed future warnings?

The death toll from the May tornado in Joplin, Missouri was so high, in part, because people didn’t heed the warnings. There had been so many false alarms in the past that they didn’t think it necessary to take shelter.

In August, five people died and dozens were injured when an outdoor stage collapsed at the Indiana State Fair due to high winds. The sky had turned black as a storm rolled in and but few people left.

We have more weather information than at any time in our past. NOAA’s predictions of the paths of hurricanes get better and better. We get warnings that a tornado is headed our way with plenty of time to take shelter. We can learn to make our own predictions from the plethora of raw data available online and even have instant access to weather information on our computers and smartphones.

But that hasn’t made us immune to the dangerous and costly effects of weather. A study earlier this year [PDF] estimated the cost of weather in the United States may be as high as $485 billion a year. “It’s clear that our economy isn’t weatherproof,” says NCAR scientist Jeffrey Lazo, the study’s lead author. “Even routine changes in the weather can add up to substantial impacts on the U.S. economy.”

I don’t mean to imply that all those costs are avoidable, but surely there’s room for improvement, especially when it comes to personal safety. I worry that many people have become so dependent on technology and the forecasts and advice from others (whether professional meteorologists or friends and family) that we don’t look at the skies anymore. The wind kicks up, the skies turn black, and we don’t do anything. We don’t take shelter. We don’t change our schedules. We don’t slow our cars. And it’s no wonder when bad things happen.

What’s to be done? Well, take the time to educate yourself about the warning signs of severe weather. Learn about hurricanes, tornadoes, floods or any other type of weather event that may strike your area before the threat becomes real. Heed the warnings of professionals, even if they later turn out to be false. Take shelter when the weather takes a turn for the worse. Go home early, before a storm begins. And err on the side of caution. Because it’s better to waste a little time and money than end up dead.

A medium-size solar flare with a coronal mass ejection, captured by the Solar Dynamics Observatory on June 7, 2011. (credit: NASA/SDO)

It can take a long time to clean up from natural disasters. New Orleans still had remnants of Katrina damage years after the storm barreled through. Hundreds of thousands of people are still homeless in Haiti, more than a year and a half after its earthquake. Areas of Japan may be off limits for years due to the earthquake/tsunami/nuclear disaster at Fukushima.

But as bad as these events might be, they are at least limited geographically. But that probably won’t be true when it comes to a severe solar storm, say scientists in a new study in Space Weather. Before I go into that, though, let’s first review what I mean by solar storms. These are explosions on the Sun that send energized particles out into space. If Earth is in the way of a mild outburst, we get pretty auroras at the poles. But more violent events can have bigger impacts, as Robert Irion noted earlier this year in his Smithsonian story “Something New Under the Sun“:

The most intense solar storm ever recorded struck in the summer of 1859. British astronomer Richard Carrington observed a giant network of sunspots on September 1, followed by the most intense flare ever reported. Within 18 hours, Earth was under magnetic siege. Dazzling northern lights glowed as far south as the Caribbean Sea and Mexico, and sparking wires shut down telegraph networks—the Internet of the day—across Europe and North America.

A magnetic storm in 1921 knocked out the signaling system for New York City’s rail lines. A solar storm in March 1989 crippled the power grid in Quebec, depriving millions of customers of electricity for nine hours. And in 2003, a series of storms caused blackouts in Sweden, destroyed a $640 million Japanese science satellite and forced airlines to divert flights away from the North Pole at a cost of $10,000 to $100,000 each.

Our modern, globally connected electronic society is now so reliant on far-flung transformers and swarms of satellites that a major blast from the Sun could bring much of it down. According to a 2008 report from the National Research Council, a solar storm the size of the 1859 or 1921 events could zap satellites, disable communication networks and GPS systems and fry power grids at a cost of $1 trillion or more.

These storms are getting more attention in recent months because the Sun has left its solar minimum—its time of least activity—and there are still three to five years until it reaches solar maximum. And although a host of satellites are now watching the Sun, leading to new insight into its activity and, eventually, better warnings of devastating storms, our technological society is still disturbingly vulnerable.

Back to the Space Weather study: Researchers from UCLA and elsewhere used simulations of solar storms to examine what would happen to the Earth’s inner radiation belt, a region of charged particles that surrounds the planet and acts as a buffer against radiation. They found that a storm the intensity of the 2003 event would halve the thickness of the radiation belt and one the size of the 1859 event would nearly wipe it out. And that would just be the beginning of the problem, New Scientist explains:

In the absence of the cloud, electromagnetic waves [would accelerate] large numbers of electrons to high speed in Earth’s inner radiation belt, causing a huge increase in radiation there. The inner radiation belt is densest at about 3000 kilometres above Earth’s equator, which is higher than low-Earth orbit. But the belt hugs Earth more tightly above high latitude regions, overlapping with satellites in low-Earth orbit.

Speeding electrons [would] cause electric charge to accumulate on satellite electronics, prompting sparks and damage. Increasing the number of speeding electrons would drastically shorten the lifetime of a typical satellite, the team calculates.

The satellite-damaging radiation could hang around for a decade, the scientists say. In addition, the radiation could also be hazardous for astronauts and equipment on the International Space Station.

Irene created a new channel across a North Carolina barrier island (courtesy of flickr user NCDOTcommunications)

When I first learned about barrier islands, back in high school, I couldn’t believe that people would live on one. That’s because barrier islands aren’t permanent; they’re just accumulations of sand that form off the coast (many can be found on the U.S. East Coast). And it’s a natural state for these islands to grow and erode and get washed away. A strong enough storm can cut an island in half, as seen after Irene in the photo above, or take away the wide swath of beach that had been between homes and the ocean. What had been prime beachfront property one day can be open ocean the next.

And people can compound the problem. The point of buying beachfront property is to get a great view of the ocean, but destroying the sand dune to get closer to the beach eliminates the feature that protects the beach from erosion. In addition, building jetties and adding sand in attempts to keep an island stable can hasten erosion elsewhere. Building on a barrier island can also limit the island’s usefulness in protecting the mainland coast from powerful storms as well as eliminate important ecosystems, such as dunes and salt marshes.

The best way to limit development on these fragile islands is probably not to outlaw it, though. There’s so much development already on these islands that there’s no possibility of clearing it all away and letting nature take over. But we could add more of these islands to the Coastal Barrier Resources System. People are not prohibited from developing land in this system. Instead, the act that created the system “limits the Federal financial assistance for development related activities such as spending for roads, wastewater systems, potable water supply, and disaster relief,” NOAA explains. In other words, you can build here, but you’re not getting any help from the feds.

As a result of this program, NOAA estimates that U.S. taxpayers saved $1.3 billion between 1982 and 2010. People do build on CBRS land, but it’s more expensive to do so without federal assistance, so less development occurs. And because the land is less developed, these ecosystems often stay intact, providing homes for migratory birds, rare plants and animals. The land is also allowed to grow and erode naturally and serve as the barrier it is meant to be.

Flood debris on the Ohio River is halted by a dam (Photo by Michael Mooney; courtesy of flickr user LouisvilleUSACE)

When the post-hurricane floods drain away, there will be tons of debris left behind. More may be washed away and never seen again. Whole buildings may flow down rivers into the oceans. But what happens then?

Some insight into this phenomenon can be found in Flotsametrics and the Floating World, the 2009 book by oceanographer Curtis Ebbesmeyer and science writer Eric Scigliano:

Today the evening news reports excited on all the houses, cars, and other flotsam washed away in floods. Rarely, however, do we learn what happens afterward to this diluvial debris. Some of the trees washed away in the great 1861-62 flood stranded on nearby shores. Coastal eddies, observable from earth-orbiting satellites, spun others a hundred miles offshore, where the California Current swept them on westward to the Hawaiian Islands. In September 1862, Charles Wolcott Brooks, secretary of the California Academy of Sciences, reported “an enormous Oregon tree about 150 feet in length and fully six feet in diameter about the butt” drifting past Maui. “The roots, which rose ten feet out of water, would span about 25 feet. Two branches rose perpendicularly 20 to 25 feet. Several tons of clayish earth were embedded among the roots”—carrying who knows what biological invaders to vulnerable island habitats.

Any logs that got past Hawaii without being snatched or washed up would, over the next five to ten years, complete a full orbit around the Turtle and/or Aleut gyres.

It might also be possible for flood debris to form a floating island. Not just a fantasy in fiction, floating islands are a fairly common lake phenomena:

The influential early-twentieth-century paleontologist William Diller Matthew estimated that a thousand islands drifted out to sea during the seventeenth, eighteenth, and nineteenth centuries, and 200 million during the Cenozoic era. Such islands, formed when soil collects on dense mats of fallen trees and other debris, were known on the lakes of Europe, the marshes of Mesopotamia, and the log-jammed rivers of the Pacific Northwest….Today engineers and harbor authorities clear out such accumulations [from rivers and inlets] before they block passage and menace shipping. But untended, they would pile up until enormous floods washed them out to sea, there to drift, taunting mariners and bedeviling mapmakers, until they broke apart on the waves or crashed onto new shores.

The most famous floating island on the ocean was spotted in the spring of 1892 off the east coast of Florida:

It was a season of extreme weather: hurricanes, tsunamis, and floods violent enough to uproot whole sections of forest. One such section became the only wooded island ever observed transversing an ocean. Thirty-foot trees enable mariners to see it from seven miles away. The U.S. Hydrographic Office feared it would menace transatlantic steamers, and inscribed it on the monthly pilot charts that marked such threats as icebergs, underwater mines, burning vessels, and floating logs. Many captains stared in disbelief when they received their November 1892 chart for the North Atlantic; it showed an island floating in the stream. But this was no cloud or mirage; it had been sighted six times along a 2,248-nautical-mile course.

(Read more about ocean currents and how they brought lost Japanese sailors to America in this except from Flotsametrics.)

In this GOES satellite image taken on August 24, the eye Hurricane Irene, traveling over the Bahamas, can be clearly seen (Credit: NOAA/NASA GOES Project)

Not that long ago, people got little to no warning about hurricanes. They couldn’t know when the winds would kick up, when the surge of water would arrive, what kind of destruction a storm might bring. But now we have satellites orbiting overhead, powerful computers that can forecast a track days in advance and plenty of scientists to make sense of a wealth of data. We may not be invulnerable, but we can, at least, limit the amount of destruction and loss of life. (If anyone asks, “what good is science?” here’s a great example.)

And because this is mostly government-funded science, the public gets plenty of access to information and tools to help us better understand hurricanes and prepare for them.

“Understanding the history of hurricane landfalls in your community is an important step toward assessing your vulnerability to these potentially devastating storms,” says Ethan Gibney, a senior geospatial analyst for NOAA. He’s one of the developers of NOAA’s Historical Hurricane Tracks online mapping application. Users can map the tracks of storms around the world and get detailed information about tropical cyclones going back to 1842.

Information about Irene (as well as Tropical Depression 10, brewing in the Atlantic) is available from the National Hurricane Center. Most of us will be satisfied with the array of maps, advisories, podcasts and videos produced by the center, but even more detailed analysis tools are also available to those who are interested and understand it.

NASA monitors storms from above the Earth and publishes the best of its imagery online. Instruments on the GOES and Terra satellites provide great visible images along with temperature (of both air and sea surface), pressure, wind and cloud data. The TRMM satellite, meanwhile, measures the hurricane’s rainfall and gives insight into the storm’s structure.

And anyone who lives near Irene’s projected path should consult FEMA’s hurricane site and learn what they should do to prepare.

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page. And apologies for the East-Coast-centric coverage the last few days; we’ll go back to regular science blogging once the Smithsonian office is no longer plagued by natural disasters. Good luck to all who sit in Irene’s path.

A building in the northern reaches of Narragansett Bay, Rhode Island, that was destroyed in the 1938 hurricane (credit: NOAA Photo Library/Donated by Susan Medyn, Tiverton, Rhode Island)

A storm formed in the eastern Atlantic near the Cape Verde Islands on September 4, 1938, and headed west. After 12 days, before it could reach the Bahamas, it turned northward, skimming the East Coast of the United States and picking up energy from the warm waters of the Gulf Stream. On September 21, it crashed into Long Island and continued its way north at a speed of 60 miles per hour, with the eye of the storm passing over New Haven, Connecticut. It didn’t dissipate until it reached Canada.

The winds were strong enough that modern scientists place the storm in Category 3 of the Saffir-Simpson Scale. The Blue Hill Observatory outside Boston measured sustained winds of 121 miles per hour and gusts as strong as 186 miles per hour. The winds blew down power lines, trees and crops and blew roofs off houses. Some downed power lines set off fires in Connecticut.

But it was the storm surge that caused the most damage. The storm came ashore at the time of the high tide, which added to the surge of water being pushed ahead by the hurricane. The water rose 14 to 18 feet along much of the Connecticut coast, and 18 to 25 feet from New London, Connecticut to Cape Cod, Massachusetts. Seaside homes all along Narragansett Bay, Rhode Island were submerged under 12 to 15 feet of water, and Providence, Rhode Island was inundated with 20 feet. Whole communities were swept out to sea.

One of the homes that washed away was Katharine Hepburn‘s beach house in Old Saybrook, Connecticut. Hepburn would later recall:

It was something devastating—and unreal—like the beginning of the world—or the end of it—and I slogged or sloshed, crawled through ditches and hung on to keep going somehow—got drenched and bruised and scratched—completely bedraggled—finally got to where there was a working phone and called Dad. The minute he heard my voice he said, ‘how’s your mother?’—And I said—I mean I shouted—the storm was screaming so—’She’s all right. All right, Dad! But listen, the house—it’s gone—blown away into the sea!’ And he said, ‘I don’t suppose you had the brains enough to through a match into it before it went, did you? It’s insured against fire, but not against blowing away!—and how are you?’

The hurricane, one of the most destructive to ever hit New England, was followed by massive river flooding as the water dumped by the storm—10 to 17 inches fell on the Connecticut River basin—returned to the sea. By the time the devastation was over, 564 people were dead and more than 1,700 injured, 8,900 homes were completely gone as were 2,600 boats. Trees and buildings damaged by the storm could still be seen by the 1950s.

In the days and weeks following the storm, the federal government sent thousands of men from the Works Progress Administration to assist with the search for survivors and the huge effort to clear away the destruction, as can be seen in this newsreel from the time:

Earthquake hazard map for the United States (credit: USGS)

Just before 2 p.m. this afternoon, my office began to shake. At first I thought it was just another train passing by but then the shaking got stronger. Earthquake! I dived under my desk while other people ran for the stairs. The USGS quickly reported that a magnitude 5.9 5.8 quake had struck in Mineral, Virginia, about 75 miles southwest of where I sat in Washington, D.C. People reported shaking as far away as Cleveland, Toronto, Chicago and South Carolina.

When we think about earthquakes in the United States, California comes to mind. Maybe Oregon or Washington or Alaska, which also sit on the Pacific Ring of Fire, or Hawaii, with its volcanic action. But those aren’t the only places where earthquakes have occurred in the United States, as you can see from this hazard map. I was actually researching this very topic as the earthquake started; Colorado, another site not known for quakes, experienced a 5.3 magnitude earthquake this morning and I had been wondering where else might be next.

The upper Midwest is seismologically pretty safe, according to the USGS, but there’s that big red and fuchsia spot in the center, where five states meet. That’s the New Madrid Seismic Zone, and four of the largest U.S. earthquakes ever (in 1699, 1811 and two in 1812) were centered there. Scientists aren’t quite sure if another big one could happen there again, but the USGS erred on the safe side in a 2009 report and remained concerned about a destructive quake.

Another fuchsia area in an unlikely spot is in South Carolina. Back in 1886, a magnitude 7.3 quake shook Charleston, killing more than 100 people. It was the largest and most destructive earthquake east of the Mississippi. The area’s fault zone has been active for thousands of years and is likely to remain so. And if a similar earthquake struck today, one simulation estimated that 900 people would be killed and the quake would cause $200 billion in damage.

Out West, Colorado gets earthquakes rarely, but Montana, Idaho, Wyoming and Utah are more active. Montana was the site of one of the country’s most intense quakes, in 1959, when a magnitude 7.3 earthquake shook Yellowstone. And Nevada, too, isn’t quake-free.

New Englanders feel earthquakes once in a while, though they’re often centered farther north in Quebec, Canada. But Boston experienced a bad earthquake back in 1755, and New York City in 1884.

And what about Washington, D.C.? Well, as you can see from the map, the hazard isn’t zero, and it’s even higher in Virginia, where today’s quake happened. The ground could shake again. But next time, I probably won’t mistake it for a train.

(Oh, and all my colleagues who evacuated the building in fear? Well, that wasn’t the best strategy, as FEMA explains. If you’re inside, you should drop to the ground, take cover under something like a desk and hang on until the shaking stops. Then you can take the stairs, not the elevator, if you’re going outside.)

What would you do in an earthquake? (Credit: xkcd)

The key moment of the Don Quijote mission: the impact as Hidalgo smashes into the asteroid and Sancho observes from a safe distance (Credit: ESA - AOES Medialab)

The most likely way that the universe could eliminate life on planet Earth has to be with an asteroid; the planet won’t be swallowed by the Sun or destroyed in some other astronomical catastrophe anytime soon. In his book Death From The Skies!, Bad Astronomy blogger Phil Plait writes:

The American astronomer Alan Harris has composed a table of risks from impacts, and the results are surprising: if you live in the United States, the overall risk of dying from an impact in your lifetime is only 1 in 700,000, somewhat less than being killed in a fireworks accident, but still more probably than being killed on an amusement park ride or by an act of terrorism.

The odds of a truly horrible impact along the lines of the one that killed off the dinosaurs 65 million years ago are even more remote. And, as Plait notes, these impacts are, theoretically at least, preventable. But blowing up an asteroid, a la the movie Armageddon, isn’t the best option—it only creates multiple asteroids still headed towards Earth. Deflection, though, might work—just give the rock a little nudge and it should pass safely by.

Scientists began preparing for a practice run of this deflection technique with a mission from the European Space Agency called Don Quijote. The plan calls for two spacecraft to head to an asteroid (possible targets are 2002 AT4 and (10302) 1989 ML). One of those spacecraft would be an impactor, named Hidalgo. Its duty would be simple—hit the asteroid within 50 meters of a target. The second spacecraft, named Sancho, would be loaded up with equipment for imaging and monitoring the asteroid. Sancho would orbit the asteroid during the impact and for months afterwards to record any changes in the asteroid’s direction.

A minor worry comes from the fact that both potential targets are not that far away from Earth. Could changing the path of one ultimately send it hurtling towards our own planet? Could we be our own downfall? Such an impact, with an origin of our own making, would be ironic, to say the least.

But ESA says it’s not a problem:

Even a very dramatic impact of a heavy spacecraft on a small asteroid would only result in a minuscule modification of the object’s orbit. In fact the change would be so small that the Don Quijote mission requires two spacecraft—one to monitor the impact of the other. The second spacecraft measures the subtle variation of the object’s orbital parameters that would not be noticeable from Earth.

Target objects can also be selected so that all possible concerns are avoided altogether, by looking into the way the distance between the asteroid’s and the Earth’s orbits changes with time. If the target asteroid is not an ‘Earth crosser’…testing a deflection manoeuvre represents no risk to the Earth.

Anyway, planning for Don Quijote is still ongoing—for example, researchers just published a paper about what kind of measurements such a mission would require—and an actual impact is years in the future, if it ever occurs. And surely we’ll have worked out how to protect our planet from such an impact by the time any such danger becomes imminent, right?

One of the most dangerous jobs in science has to be a volcanologist. When you watch the video above you can see why (although trying to get that close to a bubbling cauldron of lava is not just dangerous; it’s stupid enough that even your fellow volcanologists will yell at you). But collecting and analyzing samples of lava and deadly gases are just a couple tools in the volcanologist’s box; here are some of the other—safer—ways they study volcanoes:

Measure seismic activity: Earthquakes are an early warning sign that something is going on underground with a volcano. The rumblings can be difficult to interpret, but an increase in activity often presages an eruption.

Measure ground movements: Scientists often set up sensitive tiltmeters that can detect the tiniest changes in the shape of a volcano’s surface. Before an eruption, the volcano may start to bulge as magma accumulates closer to the surface. Before Mount St. Helens erupted in 1980, the north side of the volcano visible bulged, but more often this deformation is detectable only with sophisticated equipment.

Take the volcano’s temperature: If a volcanologist wants to see how hot a volcano has become and which lava flows are newer (and hotter), there’s no need to get up close. A thermal imaging camera on an airplane or satellite can take a picture and identify the hot spots.

Check on its geophysical properties: Minute changes in the electrical conductivity, magnetic field and even gravity around a volcano can indicate that something is brewing beneath the surface.

Map it in three dimensions: A 3-D map of all the nooks and crannies on the surface of a volcano can help scientists make predictions about where the lava will flow and who is most in danger in the event of an eruption.

Study the volcano’s past: Scientists examine geologic deposits to learn about past eruptions, which can give important clues to what a volcano may do in the future.

(HT: Bad Astronomy)

The loss of wolves in the American West set off a cascade of changes to the region's food web. Courtesy of Flickr user WSK_2005.

Eliminating predators from an area may be seen as a good thing; you’ve gotten rid of the animal that has been killing off your livestock or even your neighbors. Others often see the loss of these species with a somewhat sad, romantic eye; how awful to never again see such a creature. But the reality of the loss of predators is far worse, say ecologists reporting in Science, and “may be humankind’s most pervasive influence on nature,” they write.

Part of that is because the worst extent of such a disappearance—extinction—is irreversible, unlike other environmental impacts, such as climate change. But it’s more because the loss, or even reduction in numbers, of predators in an ecosystem can set off something caused a “trophic cascade” in which the change in predator population has effects across the food web and ecosystem. For example, when wolves were eliminated from the American West, there were changes in the elk population and the vegetation the elk ate.

“Trophic cascades have now been documented in all of the world’s major biomes—from the poles to the tropics and in terrestrial, freshwater and marine systems,” the scientists write.

But changes to the food web aren’t the primary problem for human populations; the effects on ecosystem processes are often more dangerous. And many of these processes are big enough that even people in industrialized nations cannot protect themselves. The changes in vegetation that occur when the herbivore population is allowed to rise unchecked can change the frequency and intensity of wildfires. Infectious diseases can become more common; for example, in some parts of Africa where lions and leopards have become scare, populations of olive baboons have changed their behavior patterns, increasing their contacts with the humans nearby. Intestinal parasites have become more common in both the baboons and the people.

Then there are changes to soil bacteria, water availability, biodiversity and a host of other ecosystem features that we depend on to grow our food, keep our environment habitable and stay healthy. The scientists conclude:

We propose that many of the ecological surprises that have confronted society over the past centuries—pandemics, population collapses of species we value and eruptions of those we do not, major shifts in ecosystem states, and losses of diverse ecosystem services—were caused or facilitated by altered top-down forcing regimes associated with the loss of native apex consumers or the introduction of exotics. Our repeated failure to predict and moderate these events result not only from the complexity of nature but from fundamental misunderstandings of their root causes.

We can’t predict what will happen when a predator is lost from an ecosystem; there are too many unknown ways that species interact and the processes take place over scales of tens to thousands of square kilometers. The true effect of a loss can’t be known until years or decades after it has taken place. It’s another reason to save these incredible creatures—for our futures.

With this reminder of the importance of predators, we’ve decided to hold Predator Week here at the blog. What’s your favorite predator, either existing or extinct? Which ones would you be sad to lose forever?