from the world's big
Seismic data from 2016 reveals a rare bi-directional boomerang earthquake.
- An earthquake ran quickly east before turning west beneath the Atlantic Ocean near the equator in 2016.
- Such earthquakes are likely to pack significantly more destructive power.
- Land-based boomerang earthquakes may have been witnessed, but have never been recorded seismographically.
It was definitely an odd story Rosario García González told in the summer of 2010.
González is an elder of the indigenous Cucapah community in Baja, California/Mexico. He and his wife were in their trailer in Paso Inferior, about 12 miles south-southwest of Mexicali when they heard and felt the distinct, powerful rumble of earthquake moving across their valley. Looking outside, they watched as a cloud of light-colored dust was thrown up into the air along a path going in the opposite direction, as if a truck was retracing the earthquake's path. Except there was no truck.
It's not that scientists didn't believe González's story — they just couldn't figure out what he saw. Could an earthquake possible boomerang? The answer appears to be yes. A new study of seismic data has found clear evidence of another boomerang earthquake — technically a "back-propagating supershear rupture" — that shot back and forth deep beneath the Atlantic Ocean in 2016.
Boom and back
Reconstruction of Romanche fracture zone
The research was conducted by scientists from the University of Southampton and Imperial College, London in the U.K. First author Stephen Hicks of Imperial College says, "Whilst scientists have found that such a reversing rupture mechanism is possible from theoretical models, our new study provides some of the clearest evidence for this enigmatic mechanism occurring in a real fault."
The 2016 magnitude 7.1 quake occurred along the Romanche fracture zone — this is a 559 mile-long fault line near the Atlantic equator, about 650 miles west of the coast of Liberia.
Speaking to National Geographic, Hicks recalled the discovery of what at first seemed like a pair of pulses, which closer examination indicated might actually be two phases of the same quake. If so, the quake zipped eastward, and then west. "This was a weird sort of configuration to see," he says. Confirmation of the boomerang was provided by Ryo Okuwaki of Japan's University of Tsukuba via the identification of seismic echoes from the distant event.
"Even though the fault structure seems simple, the way the earthquake grew was not, and this was completely opposite to how we expected the earthquake to look before we started to analyse the data," admits Hicks.
When modeled, the data collected by 39 seismometers arrayed along the bottom of the ocean-floor gash depicted a temblor that moved rapidly in one direction before suddenly turning around and going back in the other at a blistering 11,000 miles per hour. This likely caused seismic waves to pile up similarly to what happens with air-pressure waves trigger a sonic boom, significantly magnifying the quake's power.
Rosario García González points to where the earthquake doubled back.
Image source: CISESE/USGS
While it's logistically simpler to record and study earthquakes on land thanks to the availability of seismometer networks, land-based temblors tend to track complex fault systems, with geological slips occurring in a series like falling dominoes. Sea-bottom quakes appear to be simpler, making it easier to discern their underlying mechanisms and travels.
Only a few boomerang quakes have ever been recorded, and examples of them on land are virtually nonexistent, making accounts such as González's that much more valuable. Clearly, quakes that double back on themselves stand to do considerably more damage than one-way shakers, allowing more outward propagation of destructive seismic waves in the direction of travel, an amount that would be doubled in a boomerang. Seismologist Kasey Aderhold tells National Geographic that "studies like this help us understand how past earthquakes ruptured, how future earthquakes may rupture, and how that relates to the potential impact for faults near populated areas."
Scientists developing computer models aimed at predicting seismic events haven't thus far been able to create worthy simulations of boomerang quakes, so the details provided the U.K. researchers provide some of the best information yet collected on these geologic oddities.
In one of the ocean's most lifeless places, scientists discover and resuscitate ancient organisms.
- Seemingly dead microbes from 100 million years ago spring back to life.
- The microbes were buried deep beneath the Pacific's "Point Nemo."
- There's crushing pressure beneath the seabed, but these microbes apparently survived anyway.
There is a place in the South Pacific that's as far as you can get from land. This "oceanic pole of inaccessibility" lies beneath the South Pacific Gyre that covers 10 percent of Earth's ocean surface. It's so remote that spacecraft are regularly guided down into its waters at the end of their missions. Says NASA, "It's in the Pacific Ocean and is pretty much the farthest place from any human civilization you can find."
There's another reason, though, that this so-called "Point Nemo" isn't like anywhere else. It's an oceanic desert, about as devoid of standard marine life as any stretch of water can be. Nutrients from land can't reach it, and currents keep its waters isolated from the rest of the ocean. There's also an excess of ultraviolet light out there.
While there is some microbial life floating in the area, a team of scientists from Japan and the U.S. wanted to know if anything could possibly be living in the area's desolate seabed. What they found and retrieved were seemingly lifeless microbes trapped down there for 100 million years. It turns out that the tiny organisms are still alive after all this time —all they needed was food and oxygen.
"Our main question was whether life could exist in such a nutrient-limited environment, or if this was a lifeless zone," says study leader microbiologist Yuki Morono of the Japan Agency for Marine-Earth Science and Technology. "And we wanted to know how long the microbes could sustain their life in a near-absence of food." Apparently hundred of millions of years. Take that, tardigrades.
The research in published in the journal Nature Communications.
It's hardly a hospitable environment down there, and the weight of all that water above presses down hard on anything beneath it. Organisms trapped under this kind of pressure typically die and fossilize, given a million years or so. Still, for some reason, these microbes evaded that fate.
Co-author Steven D'Hondt, a geomicrobiologist from University of Rhode Island, says, "We knew that there was life in deep sediment near the continents where there's a lot of buried organic matter. But what we found was that life extends in the deep ocean from the seafloor all the way to the underlying rocky basement."
Morono (left) and D'Hondt (right) examining cores aboard JODIES Resolution.
Image source: IODP JRSO/University of Rhode Island
The microbes were brought up through 3.7 miles of water from the ocean bottom during the JOIDES Resolution drill ship's 2010 expedition to the Gyre. The researchers extracted samples from an array of sites and depths, including pelagic clay sediments as deep as 75 meters (246 feet) beneath the sea floor.
Examining the sediment cores on the ship, the researchers found small numbers of oxygen-consuming microbes in every sample from every depth. The samples were removed from the cores to see if their occupants could be resuscitated. They were given oxygen and their presumed food of choice, substrates of carbon and nitrogen, by syringe. The samples were then sealed in glass vials and incubated.
Growth of microbes after being fed carbon (top) and nitrogen (bottom)
Image source: Morono, et al
Vials were opened after 21 days, 6 weeks, and 18 months. Stunningly, up to 99 percent of the microbes were revived, even those from the deepest — and thus oldest — cores. Some had increased 10,000 times their number, consuming all of the carbon and nitrogen they'd been given.
The scientists could hardly believe what they were seeing. "At first I was skeptical, but we found that up to 99.1 % of the microbes in sediment deposited 101.5 million years ago were still alive and were ready to eat," recalls Morono.
A bottomless research opportunity
"It shows that there are no limits to life in the old sediment of the world's ocean," says D-Hondt. "In the oldest sediment we've drilled, with the least amount of food, there are still living organisms, and they can wake up, grow and multiply."
Some have suggested that the microbe may be more recent descendants of their 100-million-year-old ancestors, but D'Hondt says there isn't enough in the way of nutrients or energy down there to support cell division. That is, unless there's some other form of energy that has been overlooked, say, some form of radiation. "If they are not dividing at all, they are living for 100 million years, but that seems insane," he says.
The complacent majority needs to step up and call for action on climate change.
- Climate change is often framed as a debate that has split society down the middle and that requires more evidence before we can act. In reality, 97 percent of scientists agree that it is real and only 3 percent are skeptical. A sticking point for some is the estimated timeline, but as Columbia University professor Philip Kitcher points out, a 4-5 Celsius temperature increase that makes the planet uninhabitable is a disaster no matter when it happens.
- In this video, 9 experts (including professors, astronomers, authors, and historians) explain what climate change looks like, how humans have already and are continuing to contribute to it, how and why it has become politicized, and what needs to happen moving forward for real progress to be made.
- David Wallace-Wells, journalist and New America Foundation National Fellow, says that the main goal of climate action is not to win over the skeptical minority, but to "make those people who are concerned but still fundamentally complacent about the issue to be really engaged in a way that they prioritize climate change in their politics and their voting and make sure that our leaders think of climate change as a first-order political priority."
If Arctic ice continues to melt at its projected rate, the bears will go extinct due to starvation by the end of the century according to a first-ever projected timeline.
- A new report on climate change by the University of Toronto is projecting that most of the polar bear population could reach extinction in under 100 years due to starvation.
- Polar bears are dependent on sea ice for hunting seals, a primary component of their diet. As temperatures rise and sea ice continues to shrink it has become increasingly challenging for the carnivores to hunt for food.
- The Arctic is likely to have warmed more than double the amount of the global average this year compared to pre-industrial temperatures.
Starving into extinction<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="6a66d2ea09b66ae24f3d997218f573f0"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/_JhaVNJb3ag?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Polar bears are dependent on sea ice for hunting seals, a primary component of their diet, and aren't exactly built for swimming to catch their prey in the open water. As temperatures rise and sea ice continues to shrink it has become increasingly challenging for the carnivores to hunt for food. The species could be starved out within the next 80 years, save for a few high-Arctic subpopulations.</p><p>"Here, we establish the likely nature, timing and order of future demographic impacts by estimating the threshold numbers of days that polar bears can fast before cub recruitment and/or adult survival are impacted and decline rapidly," the authors of the study said.</p><p>The study looked at 13 of the world's 19 subpopulations of polar bears that account for 80 percent of the species' total population. Researchers modeled the energy use of the polar bears to calculate the number of days the bears can fast before their reproductive abilities become impacted. They then mapped that onto the number of estimated iceless days that will be faced in the coming decades, determining that the amount of time the bears would be forced to fast surpassed the amount of time they were capable of fasting. In 20 years from now, some polar bears living in Canada will begin to face reproductive failure and in 40 years a majority of the global population will more than likely be affected. </p><p>"The dire predictions in our study result from polar bear's dependence on sea ice and the projected rapid loss of that ice due to human-driven climate change," Marika Holland, co-author of the paper <a href="https://time.com/5869316/climate-change-pushes-polar-bears-towards-extinction-study-finds/" target="_blank">told TIME</a>.</p><p>While the scientists noted that moderate cuts in emissions could potentially extend the bears' estimated life-expectancy for a bit, it won't be able to save some species populations from extinction by the end of the century.</p><p>"Land-based feeding is unlikely to occur at scales that shift the timelines for recruitment and survival declines by more than a few years, because foods that meet the energy demands of polar bears are largely unavailable on land," the study said, pointing out that some polar bear populations are already feeling the impact.</p>
The melting arctic<p>Of course, as the <a href="https://www.iucn.org/content/action-now-save-polar-bears" target="_blank">International Union for Conservation of Nature</a> has cited, climate change is the main cause of the population's suffering and decline.</p><p>According to the World Meteorological Organization, the Arctic is likely to have warmed more than double the amount of the global average this year compared to pre-industrial temperatures. Since the 1970s, satellites have shown sea ice melting by 13 percent per decade. If greenhouse gas emissions stay on their current trajectory, the only polar bears that will be left by the end of the century will likely be those living in the Queen Elizabeth Islands in Canada's Arctic Archipelago. </p><p>Keeping tabs on polar bears, the largest land-dwelling carnivore on earth, is how scientists keep their finger on the pulse of the health of Arctic populations at-large. Their loss, as Holland <a href="https://time.com/5869316/climate-change-pushes-polar-bears-towards-extinction-study-finds/" target="_blank">told TIME</a>, "would reverberate throughout the ecosystem." </p><p>But the bears won't go down without a fight for their survival. As Arctic temperatures rise, melting the species' normal hunting grounds, the bears may begin to move toward land to find food. For example, in 2019 authorities in Russia's remote arctic region declared a state of emergency as a mob of starving polar bears charged into villages. </p>
Any hope?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUxMTYxMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMTM5ODY0M30.RqKPGBEzFaJsP81U2JcpbnMglhCYfg-TQpG7qPZT6H4/img.jpg?width=1245&coordinates=0%2C301%2C0%2C302&height=700" id="c7cea" class="rm-shortcode" data-rm-shortcode-id="f92dedfaaf59e0d8df8c00e016d1f288" data-rm-shortcode-name="rebelmouse-image" alt="arctic fox in snow" />
Arctic foxes are another species endangered as their habitats and diets are threatened by melting sea ice due to greenhouse gas emissions.Photo by Jonatan Pie on Unsplash<p>Polar bears have faced extermination in the past. In 1965, scientists were worried that commercial polar bear hunting would cause the species to go extinct. A 1973 worldwide ban on hunting led to a resurgence in bear population, yet the melting sea ice that now threatens the lives of the <a href="http://pbsg.npolar.no/export/sites/pbsg/en/docs/2019-StatusReport.pdf" target="_blank">estimated 26,000</a> that live on earth today is a much more complex issue to solve. While the species' future looks grim, the study does point out that decreasing fossil fuel burning may reduce Arctic sea ice loss. </p><p>If there is a sliver of hope left for the polar bears and <a href="https://www.un-habitat.org/endangered-animals-arctic-region/" target="_blank">other Arctic species</a> endangered by melting Arctic ice, it rests on rapid and radical human action against fossil fuel emissions.</p>
These alien-like creatures are virtually invisible in the deep sea.
- A team of marine biologists used nets to catch 16 species of deep-sea fish that have evolved the ability to be virtually invisible to prey and predators.
- "Ultra-black" skin seems to be an evolutionary adaptation that helps fish camouflage themselves in the deep sea, which is illuminated by bioluminescent organisms.
- There are likely more, and potentially much darker, ultra-black fish lurking deep in the ocean.
The Pacific blackdragon
Credit: Karen Osborn/Smithsonian<p>When researchers first saw the deep-sea species, it wasn't immediately obvious that their skin was ultra-black. Then, marine biologist Karen Osborn, a co-author on the new paper, noticed something strange about the photos she took of the fish.</p><p style="margin-left: 20px;">"I had tried to take pictures of deep-sea fish before and got nothing but these really horrible pictures, where you can't see any detail," Osborn told <em><a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">Wired</a></em>. "How is it that I can shine two strobe lights at them and all that light just disappears?"</p><p>After examining samples of fish skin under the microscope, the researchers discovered that the fish skin contains a layer of organelles called melanosomes, which contain melanin, the same pigment that gives color to human skin and hair. This layer of melanosomes absorbs most of the light that hits them.</p>
A crested bigscale
Credit: Karen Osborn/Smithsonian<p style="margin-left: 20px;">"But what isn't absorbed side-scatters into the layer, and it's absorbed by the neighboring pigments that are all packed right up close to it," Osborn told <em>Wired</em>. "And so what they've done is create this super-efficient, very-little-material system where they can basically build a light trap with just the pigment particles and nothing else."</p><p>The result? Strange and terrifying deep-sea species, like the crested bigscale, fangtooth, and Pacific blackdragon, all of which appear in the deep sea as barely more than faint silhouettes.</p>
David Csepp, NMFS/AKFSC/ABL<p>But interestingly, this unique disappearing trick wasn't passed on to these species by a common ancestor. Rather, they each developed it independently. As such, the different species use their ultra-blackness for different purposes. For example, the threadfin dragonfish only has ultra-black skin during its adolescent years, when it's rather defenseless, as <em>Wired</em> <a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">notes</a>.</p><p>Other fish—like the <a href="http://onebugaday.blogspot.com/2016/06/a-new-anglerfish-oneirodes-amaokai.html" target="_blank">oneirodes species</a>, which use bioluminescent lures to bait prey—probably evolved ultra-black skin to avoid reflecting the light their own bodies produce. Meanwhile, species like <em>C. acclinidens</em> only have ultra-black skin around their gut, possibly to hide light of bioluminescent fish they've eaten.</p><p>Given that these newly described species are just ones that this team found off the coast of California, there are likely many more, and possibly much darker, ultra-black fish swimming in the deep ocean. </p>