A new blood test might reveal whether someone is at risk of getting Alzheimer’s disease.

The test measures blood plasma levels of a sticky protein called amyloid-beta. This protein can start building up in the brains of Alzheimer’s patients decades before there’s any outward signs of the disease. Typically, it takes a brain scan or spinal tap to discover these A-beta clumps, or plaques, in the brain. But evidence is growing that A-beta levels in the blood can be used to predict whether or not a person has these brain plaques, researchers report online January 31 in Nature.
These new results mirror those of a smaller 2017 study by a different team of scientists. “It’s a fantastic confirmation of the findings,” says Randall Bateman, an Alzheimer’s researcher at Washington University School of Medicine in St. Louis, who led the earlier study. “What this tells us is that we can move forward with this [test] approach with fairly high confidence that this is going to pan out.”

There’s currently no treatment for Alzheimer’s that can slow or stop the disease’s progression, so catching it early can’t currently improve a patient’s outcome. But a blood test could help researchers more easily identify people who might be good candidates for clinical trials of early interventions, says Steven Kiddle, a biostatistician at the University of Cambridge, who wasn’t part of either study.

Creating such a test has been challenging: Relatively little A-beta floats in the bloodstream compared with how much accumulates in the brain. And many past studies haven’t found a consistent correlation between the two.

In the new study, researchers used mass spectrometry, a more sensitive measuring technique than used in most previous tests, which allowed the detection of smaller amounts of the protein. And instead of looking at the total level of the protein in the blood, the team calculated the ratios between different types of A-beta, says coauthor Katsuhiko Yanagisawa, a gerontologist at the National Center for Geriatrics and Gerontology in Obu, Japan.
He and his colleagues analyzed brain scans and blood samples from a group of 121 Japanese patients and a group of 252 Australian patients. Some participants had Alzheimer’s, some didn’t, and some had mild cognitive impairments that weren’t related to Alzheimer’s.

Using the ratios, the researchers found that they could discriminate between people who had A-beta plaques in the brain and those who didn’t. A composite biomarker score, created by combining two different ratios, predicted the presence or absence of A-beta plaques in the brain with about 90 percent accuracy in both groups of patients, the researchers found.

The new results are promising, Kiddle says, but the test still needs more refining before it can be used in the clinic. Another wild card: the cost. It’s still not clear whether the blood test will be more affordable than a brain scan or a spinal tap.

Controlled thermonuclear fusion is moving so well that full-scale development could begin within five years, says Dr. David J. Rose….It might take 20 to 30 years beyond that before fusion could move into the power grid, though, he predicts. — Science News, February 17, 1968

Update
Governments and private-sector start-ups are still trying to wrangle thermonuclear fusion — the process that lights up stars and ignites hydrogen bombs — for clean energy, with limited progress (SN: 2/6/16, p. 18). One of the biggest ongoing projects is ITER in France, an international effort to build the first magnetic fusion reactor that pumps out more energy than it consumes. ITER plans to flip on the machine in 2025. Optimistic estimates put the first fusion power plants on the grid no sooner than 2040.

AUSTIN, Texas — To reduce your impact on air quality, you might expect to trade in your gas-guzzling clunker of a car — but you can also unplug those air fresheners.

In urban areas, emissions from consumer goods such as paint, cleaning supplies and personal care products now contribute as much to ozone and fine particulate matter in the atmosphere as do emissions from burning gasoline or diesel fuel.

The finding is largely a sign of success, study coauthor Brian McDonald said February 15 during a news conference at the annual meeting of the American Association for the Advancement of Science. Steps taken to clean up car exhaust over the past few decades have had a huge effect, and as a result, “the sources of air pollution are now becoming more diverse in cities,” said McDonald, a chemist at Cooperative Institute for Research in Environmental Sciences in Boulder, Colo.
“When you have a big mountain in front of you, it’s difficult to know what lies behind it,” says Spyros Pandis, a chemical engineer at Carnegie Mellon University in Pittsburgh who wasn’t part of the study. Now, other sources of air pollution are becoming more visible.

The new study, also published in the Feb. 16 Science, focused on volatile organic compounds, or VOCs, that are derived from petroleum. These are a diverse array of hundreds of chemicals that easily vaporize and make their way into the atmosphere. Some VOCs can be harmful when directly inhaled — molecules released by bleach and paint make people lightheaded, for example.

Beyond their immediate effects, VOCs react with other molecules in the air, such as oxygen and nitrogen oxides, to generate ozone as well as fine particulate matter. (Those nitrogen oxides come, in large part, from vehicle exhaust.) High levels of fine particulate matter make it hard to breathe and contribute to chronic lung problems (SN: 9/30/17, p. 18). And while ozone high in the atmosphere helps shield Earth from the sun’s ultraviolet radiation, at ground level, it mixes with fine particulates to form breath-choking smog.

Over a period of six weeks, the researchers collected air samples in Pasadena, located in the notoriously smoggy Los Angeles valley. They also evaluated indoor air quality measurements made by other scientists. The team traced the molecules found in these air samples to their original sources using databases that show the specific volatile organic compounds released by specific products.

Consumer products that emit VOCs have an outsized effect on air pollution, the team found. About 15 times as much oil and natural gas is used as fuel than ends up in consumer products ranging from soaps, shampoos and deodorants to air fresheners, glues and cleaning sprays. And yet these everyday products were responsible for 38 percent of the VOC emissions, the researchers found, while gasoline and diesel emissions accounted for only 33 percent. Consumer products also contributed just as much as fuels to chemical reactions that lead to ozone and fine particulate matter. The emissions from consumer products also dwarfed those from the production of oil and gas, called upstream emissions.
Regulations on VOCs vary by state, but most consumer products are regulated only for their potential contribution to ground-level ozone, not fine particulate matter. This study makes it clear that even though most volatile emissions from consumer products happen indoors, that air eventually gets vented outside, where it can contribute to larger-scale atmospheric pollution in multiple ways, McDonald said.

More work needs to be done to see whether other cities show the same pattern, the researchers add, as well as to figure out which kinds of VOCs might be particularly problematic. Because there are so many VOCs and they all react differently in the atmosphere, there’s still a lot to learn about which might be most likely to form fine particles and therefore be the best targets for reduction.

Part of the challenge with many these volatile-emitting products is that they’re specifically designed to evaporate as part of their job, says study coauthor Jessica Gilman, an atmospheric chemist at the National Oceanic and Atmospheric Administration in Boulder. For some products, like paints, there are low-VOC formulations available. But finding replacements for key ingredients in other products can be hard. Picking unscented versions of personal care products when possible and using the minimum amount necessary can help reduce the impact on air quality.

To play good defense against the next viral pandemic, it helps to know the other team’s offense. But the 263 known viruses that circulate in humans represent less than 0.1 percent of the viruses suspected to be lurking out there that could infect people, researchers report in the Feb. 23 Science.

The Global Virome Project, to be launched in 2018, aims to close that gap. The international collaboration will survey viruses harbored by birds and mammals to identify candidates that might be zoonotic, or able to jump to humans. Based on the viral diversity in two species known to host emerging human diseases — Indian flying foxes and rhesus macaques — the team estimates there are about 1.67 million unknown viruses still to be discovered in the 25 virus families surveyed. Of those, between 631,000 and 827,000 might be able to infect humans.
The $1.2 billion project aims to identify roughly 70 percent of these potential threats within the next 10 years, focusing on animals in places known to be hot spots for the emergence of human-infecting viruses. That data will be made publicly available to help scientists prepare for future virus outbreaks — or, ideally, to quash threats as they emerge.

“It’s ambitious,” says Peter Daszak, president of EcoHealth Alliance in New York City and a member of the Global Virome Project’s steering committee. But it’s more cost effective to head off pandemics than to deal with the aftermath, he says. “We believe we’re going to get ahead of this pandemic threat.”

THE WOODLANDS, Texas — It’s been six months since NASA’s Cassini spacecraft plunged to its doom in the atmosphere of Saturn, but scientists didn’t spend much time mourning. They got busy, analyzing the spacecraft’s final data.

The Cassini mission ended September 15, 2017, after more than 13 years orbiting Saturn (SN Online: 9/15/17). The spacecraft’s final 22 orbits, dubbed the Grand Finale, sent Cassini into the potentially dangerous region between the gas giant and its rings, and its final orbit sent it directly into Saturn’s atmosphere.
That perspective helped solve mysteries about the planet and its moons that could not be tackled any other way, scientists said March 19 at the Lunar and Planetary Science Conference in The Woodlands, Texas.

“In so many ways, the Grand Finale orbits provided information that was totally unexpected,” said Cassini project scientist Linda Spilker of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “So many of our models were not correct.”

Here are five things we now know and a few outstanding mysteries.

1. Saturn’s clouds go deep
   Those final daredevil orbits allowed Cassini to measure the gravity of Saturn and its rings independent of one another. Looking at the planet’s gravity field alone revealed that the swirling bands of clouds penetrate much deeper into the planet than expected.

Astronomers this month announced a similar discovery for an even larger gas giant, reporting that the Juno spacecraft, which is orbiting Jupiter, had found that the planet’s rotating cloud belts reach roughly 3,000 kilometers below the top of the atmosphere.

Saturn’s clouds reach a few times deeper than that. “This was an astonishing result,” Spilker said.

“People used to think that maybe Saturn was just a slightly smaller version of Jupiter, but it’s evident that that’s not the case,” says planetary scientist Paul Schenk of the Lunar and Planetary Institute in Houston, who was not involved in the gravity measurements. The difference speaks to how diverse planets are, he says. “Every place you look, everywhere we’ve been to, it’s just been so dramatically different and unique.”

2. Ring rain is eroding the innermost ring
   Grains of ice from the rings are raining down into Saturn’s atmosphere, Cassini’s final orbits confirmed. This “ring rain” idea has been suggested since the 1980s, but only by tasting the atmosphere and directly sampling the space between Saturn and the rings could Cassini confirm the rains are real.

In its last five full orbits, Cassini found a zoo of organic molecules in and just above Saturn’s atmosphere, said planetary scientist Kelly Miller of the Southwest Research Institute in San Antonio. The spacecraft found a lot of water, which wasn’t surprising — water makes up about 90 percent of the rings. But there were also a lot of hydrocarbons similar to propane, plus some methane and sulfur-bearing molecules.

The types of molecules became less well-mixed as the spacecraft looked deeper into Saturn’s atmosphere, which is what would happen if the particles came from the rings and sank at different speeds. The researchers think this material is especially raining from Saturn’s D ring, the thin innermost ring. Other Cassini data suggest this ring is losing mass.

“The D ring is slowly being eroded away and going into the planet,” Spilker said.

3. Organics could explain mysterious ring hues
   The organics in the ring rain could solve a debate about why Saturn’s rings appear reddish in some spots.

“We’ve had this debate going on for a couple of years now — are they red because of good old-fashioned rust like Mars, or because of the same kinds of organic materials … that make carrots and tomatoes and watermelon red?” said planetary scientist Jeff Cuzzi of NASA’s Ames Research Center in Moffett Field, Calif. “To me, this answers the question of what makes the rings red: It’s organics.”

It’s still not clear where the organics come from, though. They could be created within the rings, or they could come from cosmic dust from the tails of comets. Miller and her colleagues are comparing the ring rain molecules with data on comet 67P, which the Rosetta spacecraft observed, to see how well they match up (SN: 11/11/17, p. 32).

4. Titan’s “magic islands” aren’t islands, or bubbles
   Mysterious disappearing features in the lakes of Saturn’s moon Titan are caused by sunlight reflecting off giant waves, said planetary scientist Alexander Hayes of Cornell University.
   These features were named “magic islands” when they were first spotted in 2014. As recently as April 2017, planetary scientists thought they had the islands solved: They seemed to be the result of champagnelike bubbles of nitrogen burbling through the moon’s methane and ethane seas (SN Online: 4/18/17).

But Hayes presented newly analyzed data from August 2014, when Cassini looked at Kraken Mare, the moon’s largest northern sea, in radar and infrared wavelengths within two hours of each other. The radar images showed a magic island, and the infrared ones showed a peak in brightness at the same spot.

Because the observations were taken two hours apart, the island probably couldn’t have been due to bubbles, Hayes said — bubbles would pop or disperse too quickly. Instead, he thinks the brightening could be the glint of sunlight reflecting directly off of giant waves on the lake, like how the ocean ripples with gold at sunset. Simulations of Titan’s atmosphere suggest these waves could be raised by winds as slow as 0.5 meters per second, which would barely move a wind vane on Earth.

5. Enceladus’ plumes may brighten by the pull of another moon
   Saturn’s tiny moon Enceladus has plumes that may be driven by nudges from another moon.

The spurts of liquid water were discovered in 2006. Over the next six years, scientists noticed that the plumes varied in brightness (a proxy for how much material is gushing from the moon) on a daily cycle, probably driven by Saturn’s different positions in Enceladus’ sky.

Then, in 2015 some researchers noted that the plumes’ overall brightness had been decreasing since the beginning of the Cassini mission.

One possible explanation was that the plumes changed with Saturn’s seasons. Another was that ice built up in the vents, clogging them and decreasing the flow. But looking at the full 13-year dataset, planetary scientist Francis Nimmo found that the plumes grow brighter in a regular cycle every four and 11 years. The pattern is too coherent to be explained by clogged vents, said Nimmo, of the University of California, Santa Cruz. Oddly, the plume grew brighter in 2017, so the seasonal explanation doesn’t fit either.

The variations could be explained by a neighboring moon, Dione. Every time Dione and Enceladus line up, their gravitational stress on each other could force Enceladus’ vents open a bit more, causing the plumes to grow brighter.

Unsolved enigmas
So far, analyzing data from Cassini hasn’t answered all of scientists’ questions. Is Enceladus the only moon with plumes? Dione showed signs of activity, too, but Cassini wasn’t able to confirm it. How thick is Enceladus’ ice sheet? Why are Titan’s smaller lakes full of clear, pure methane, when scientists expected the lakes to be clogged with hydrocarbon silt?

Even though the spacecraft is gone, it left decades’ worth of data to sift through in search of answers. “Cassini is going to keep on giving as long as we keep looking,” Hayes said.

Editors’ note: This story was updated on March 21, 2018, to include the affiliations of Jeff Cuzzi and Francis Nimmo.

BOSTON — Conflicting results on whether brain stimulation helps or hinders memory may be explained by the electrodes’ precise location: whether they’re tickling white matter or gray matter.

New research on epilepsy patients suggests that stimulating a particular stretch of the brain’s white matter — tissue that transfers nerve signals around the brain — improves performance on memory tests. But stimulating the same region’s gray matter, which contains the brain’s nerve cells, seems to impair memory, Nanthia Suthana, a cognitive neuroscientist at UCLA, reported March 25 at a meeting of the Cognitive Neuroscience Society.
A groundbreaking study by Suthana and colleagues, published in 2012 the New England Journal of Medicine, found that people performed better on a memory task if their entorhinal cortex — a brain hub for memory and navigation — was given a low jolt of electricity during the task. But subsequent studies stimulating that area have had conflicting results. Follow-up work by Suthana suggests that activating the entorhinal cortex isn’t enough: Targeting a particular path of nerve fibers matters.

“It’s a critical few millimeters that can make all the difference,” said Suthana.

The research underscores the complexity of investigations of and potential treatments for memory loss, said Youssef Ezzyat, a neuroscientist at the University of Pennsylvania. Many variables seem to matter. Recent work by Ezzyat and colleagues found that the kind of brain activity during stimulation is also important, as is the precise timing of the stimulation (SN: 3/31/2018, p.16).

Suthana and her colleagues worked with 25 people with epilepsy who had electrodes already implanted in the brain for controlling seizures. Some people’s electrodes were in the entorhinal cortex’s gray matter, and some were in its white matter fibers, which extend to the hippocampus, an area known for its role in memory. Study participants received a low current of electricity while performing a memory task such as learning lists of words, names of objects (for example, “chair” or “cat”) or recognizing particular faces. Participants were then distracted with another task and then had to recall what they had learned previously.
People whose electrodes were stimulating white matter did better on the memory tasks, the researchers discovered. Stimulating gray matter seemed to have a detrimental effect, though there were too few participants to determine whether or not the impairment results were a fluke.

Deep brain stimulation has been heralded as a possible treatment for ills from obesity to obsessive-compulsive disorder to traumatic brain injury. But studies often rely on patients who have electrodes implanted for something other than memory so it can take years and collaborations among several institutions to collect enough data to see something meaningful. The size of electrode, its exact location, the amount of current delivered and other factors may matter more than researchers have recognized. But the devil may be in these details, which need to be noted as research unfolds, Suthana said.

“This is an opportunity as a field for us to adopt common guidelines and methods of reporting so we can better understand what’s happening,” she said.

Nearly 2,000 years ago, Pliny the Elder reported that hippopotamuses find relief from overeating by piercing their skin in a hippo version of bloodletting. Eventually, scientists learned that the oozing red stuff Pliny described isn’t even blood but a secretion that may have antibacterial and sun-blocking properties. While chasing down the truth for herself, Lucy Cooke scooped the goo from a hippo and smeared it on her own skin — if nothing else, her hand was “noticeably silkier,” she writes in The Truth About Animals.
Cooke, a zoologist and documentary filmmaker, has a storehouse of such tales of animal adventure. She’s also the founder of the Sloth Appreciation Society, whose motto is “Being fast is overrated.” That motto gives a glimpse into her sense of humor, which shines through page after page, and her affinity for misunderstood creatures. Cooke battles the notion that sloths are lazy or stupid just because they’re slow-moving. In her book, she set out to, as she writes, “create my very own menagerie of the misunderstood.”

And quite a menagerie it is. Each chapter takes on a different animal — bats, storks, vultures and pandas, among others — long shrouded in myth or misconception. Some, like bats, are unfairly maligned; others are adored despite shocking behavior, such as Adélie penguins, whose sex lives were considered so depraved that, in 1915, London’s Natural History Museum boldly marked a paper about the birds’ mating behavior as “Not for Publication.”

In many cases, science created or perpetuated myths before eventually debunking them. Among the ludicrous ideas once taken as fact: Beavers escape hunters by chewing off their own testicles and dropping them as a distraction. To explain where birds disappear in winter, Aristotle once posited that they transform into different species.
Even hard-core animal lovers will find surprises in these histories. I knew, for instance, that the long-running mystery over European and American eels’ spawning sites eventually led to the North Atlantic’s Sargasso Sea (SN Online: 4/13/17). But I had no idea that Sigmund Freud was among the many who tried to solve another eel conundrum: where the fish hide their gonads. After disemboweling hundreds of eels to find their testes, Freud threw up his hands and eventually moved on to study the human psyche, perhaps slippery enough.

In the end, the history of zoology reveals as much about our human foibles as about the animals we study. And this book will leave readers more enlightened about both.

PHOENIX — High-tech attire that would give users the sensation of being pushed, pinched or poked could someday make virtual realities feel as real as they look.

Today’s VR systems rely heavily on goggle-generated visual displays to transport users to simulated worlds. But superthin, shape-shifting sheets worn as sleeves or built into other garments could provide gamers with tactile feedback that makes virtual realities more immersive.

The new device, described April 5 at the Materials Research Society spring meeting, contains a grid of tiny, inflatable bubbles, sandwiched between two soft, stretchy silicone films. When one of these bubble wrap–like sheets is placed against a user’s skin, inflating different air pockets by different amounts at different speeds can make a gamer feel like she’s been grabbed around the wrist or patted on the back.
Some previously developed hand- or finger-worn devices have allowed wearers to feel or manipulate virtual objects. But clothing embedded with smart silicone skins could make VR gaming more of a full-body experience.

Each air pocket on the sheet is coated with a liquid metal sensor that tracks how much that bubble is distended, which helps regulate the device’s shape-shifting. Those sensors also detect indentations in the bubbles, so these sleeves could work as touch pad game controllers, too, says study coauthor Matthew Robertson, a roboticist at École Polytechnique Fédérale de Lausanne in Switzerland.

Currently, plastic tubes feed air into the device from an external pump. “Our ultimate goal is to get rid of all the tubes,” Robertson says. He imagines future versions of these VR sleeves fitted with tiny tanks of compressed gas to inflate the air bubbles.

Charles Darwin famously derived his theory of evolution from observations he made of species and their geographic distributions during his five-year voyage around the world on the H.M.S. Beagle. But in the introduction of On the Origin of Species, the naturalist also cites another influence: the thousands of fossils that he collected on that trip. Darwin’s Fossils is paleobiologist Adrian Lister’s account of that little-appreciated foundation of evolutionary theory.

While sailors on board the Beagle charted the coastal waters of South America (the actual purpose of the expedition), Darwin explored the shore and rambled inland on excursions that sometimes lasted weeks. The fossils he unearthed — some relatively fresh, others millions of years old — have tremendous significance in the history of science, Lister contends.
Many of the species Darwin discovered in the fossils were previously unknown to science, including several giant ground sloths, compact car–sized relatives of armadillos called glyptodonts (SN Online: 2/22/16) and ancient kin of horses and elephants. Because many of those animals were apparently extinct — but just as apparently related to species still living in the region — Darwin concluded the fossils were strong evidence for the “transmutation,” or evolution, of species. This evidence was all the more convincing to him, Lister suggests, because he had unearthed the fossils himself. He saw firsthand the fossils’ geologic context, which enabled him to more easily infer how species had changed through time.

Copiously illustrated and suitable for general readers as well as the science savvy, Darwin’s Fossils is a quick, easy read that provides a fascinating overview of the naturalist’s wide-ranging fieldwork during the Beagle voyage. His insights from fossils went beyond just biological evolution. Darwin’s studies of coral reefs (the mineralized parts of which are, after all, huge fossils) encircling islands in the Pacific and Indian oceans led him to theorize correctly how such reefs form. And his observations of strata containing marine fossils thousands of meters up into the Andes led to an improved understanding of how geologic forces sculpt the world.

Injecting fluid into the ground for geothermal power generation may have caused the magnitude 5.5 earthquake that shook part of South Korea on November 15, 2017. The liquid, pumped underground by the Pohang power plant, could have triggered a rupture along a nearby fault zone that was already stressed, two new studies suggest.

If it’s confirmed that the plant is the culprit, the Pohang quake, which injured 70 people and caused $50 million in damages, would be the largest ever induced by enhanced geothermal systems, or EGS. The technology involves high-pressure pumping of cold water into the ground to widen existing, small fractures in the subsurface, creating paths for the water to circulate and be heated by hot rock. The plant then retrieves the water and converts the heat into power.
Researchers examined local seismic network data for the locations and timing of the main earthquake, six foreshocks and hundreds of aftershocks to determine whether the temblors might have been related to fluid injections at the Pohang plant. Almost all of the quakes originated just four to six kilometers below surface points that were within a few kilometers of the plant, report geologist Kwang-Hee Kim of Pusan National University in South Korea and colleagues online April 26 in Science. These factors, combined with the lack of seismic activity in the region before the injections, suggest the injections were to blame for the quakes, the researchers found.
Another team led by seismologist Francesco Grigoli of ETH Zurich in Switzerland used the same methodology but analyzed data from regional and international, rather than local seismic stations. The researchers came to a similar conclusion
in a second paper published online April 26 in Science . These findings could be a “game changer” for the geothermal industry, prompting a reevaluation of the dangers associated with EGS, Grigoli and colleagues note.
Previous studies suggest that induced quakes can be closely linked to how much fluid is injected into the ground, whether for fracking (SN Online: 1/18/18), wastewater disposal (SN: 8/10/13, p. 16) or EGS. The higher the volume, the stronger the associated quakes as fluid injections increase subsurface pressures and make it easier for fractures to slip, researchers say. In the United States, the largest known human-induced earthquake, a magnitude 5.7 temblor in Oklahoma in 2011, was triggered by injections totaling some 20 million tons of wastewater from oil drilling.

The largest quake previously known to be triggered by EGS was a magnitude 3.4 temblor in Basel, Switzerland, one of a series of quakes that ultimately led to the shuttering of a geothermal power plant there.

Researchers initially believed that the injected volumes were too small to cause much shaking. The Pohang plant began injecting water in early 2016, putting a total of 12,800 cubic meters into the ground before the 2017 quake. Early quakes were small: Kim and colleagues found that each pulse of injected water was followed by a series of smaller quakes a few days later. But as the total volume in the subsurface increased with each injection, the quakes also grew a bit stronger, the team reported, suggesting that even a small increase in underground pressure can cause certain faults to rupture, depending on the structure of the fault zones.
The South Korean government is currently doing its own investigation into whether the November 15 quake was linked to EGS activity, or influenced by natural seismic activity, says Stanford University geologist William Ellsworth, a member of an international group advising the investigation. Operations at the plant are suspended until the investigation is completed, expected to be by the end of the year or early next year.

The country sits atop a number of fault lines and has had several powerful earthquakes, some as large as magnitude 7, in the last few hundred years. Seismic activity has been low since 1905. But some research suggests the magnitude 9 earthquake in Tohoku, Japan, in 2011 may have increased subsurface stress in the nearby Korean peninsula, causing an uptick in its seismicity.

“It’s still a vigorous scientific debate,” Ellsworth says. “This earthquake provides an unusual opportunity to understand much more about the connection between injections and the triggering of an earthquake.”