Smithsonian.com

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.