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Fire and rain: West to get more one-two extreme climate hits

The one-two punch of nasty wildfires followed by heavy downpours, triggering flooding and mudslides, will strike the U.S. West far more often in a warming-hopped world, becoming a frequent occurrence, a new study said.

That fire-flood combination, with extreme drenchings hitting a spot that burned within a year, could increase as much as eight-fold in the Pacific Northwest, double in California and jump about 50% in Colorado by the year 2100 in a worst-case climate change scenario of increasing greenhouse gas emissions, according to a study in Friday’s Science Advances.

The study said that as human-caused climate change intensifies, 90% of extreme fire events will be followed by at least three extraordinary downpours in the same location within five years.

Study authors said it’s because even though the West is getting drier overall—making wildfire season longer—concentrated bursts of intense rain are increasing and coming earlier so areas can get hurt by both extremes.

“One disaster is bad. Two disasters in rapid succession is even worse because you’re already reeling from the first one,” said study co-author Samantha Stevenson, a climate scientist at the University of California Santa Barbara. “But in the particular case of wildfire plus extreme rain, the wildfire is setting you up for worse consequences because you’re losing your vegetation, you’re changing soil properties and making that landscape more conducive to destructive flooding.”

Stevenson knows because the Thomas Fire, which started in late 2017 and was followed a month later by a downpour of half an inch (13 millimeters) of rain in just five minutes, caused mudslides in Montecito that killed 23 people.

“Oh yeah, it was crazy,” Stevenson said. “Like the entire highway was blocked off with like a wall of mud. There were boulders in people’s living rooms.”

For study co-author Daniel Swain, a western weather expert at UCLA who lives in Colorado, it hit even closer to home. Last week, he had to evacuate his Boulder home because of a fire. Today is the start of flash flood season.

Especially in the Pacific Northwest, fire and flood seasons keep getting longer and closer to each other. While both are get likely to get worse, extreme rainfall should increase more, Swain said.

“That’s another sort of a double whammy, a situation where you have the candle burning at both ends,” Swain said. “It’s entirely foreseeable that some of these places will literally still have fires burning when the first extreme rainfall event extinguishes them.”

The report looked at 11 Western U.S. states, concentrating on four of them where the projected increase in fires followed by downpours was most noticeable.

Study authors acknowledged that the worst-case warming scenario they studied, using dozens of large-scale climate model simulations, is becoming increasingly less likely because many but not all countries, including the United States and Europe, have been cutting emissions of heat-trapping gases.

They said they were unable at the time to use simulations of more likely scenarios with some moderate emission reductions. But in the more likely scenarios the Pacific Northwest would probably still see a four-fold increase in fire-and-flooding, said study lead author Danielle Touma, a National Center for Atmospheric Research climate scientist.

The simulations were of fire weather, not fires themselves, and downpour conditions. University of California at Merced climate scientist LeRoy Westerling, who wasn’t part of the study, said he worries about the accuracy of global computer model simulations being able to work on such a small scale. Still, he said, the results make sense.

More information: Danielle Touma, Climate change increases risk of extreme rainfall following wildfire in the western United States, Science Advances (2022). DOI: 10.1126/sciadv.abm0320www.science.org/doi/10.1126/sciadv.abm0320

Journal information: Science Advances

Earthquake faults are smarter than we usually think

Northwestern University researchers now have an answer to a vexing age-old question: Why do earthquakes sometimes come in clusters?

The research team has developed a new computer model and discovered that earthquake faults are smarter — in the sense of having better memory — than seismologists have long assumed.

“If it’s been a long time since a large earthquake, then, even after another quake happens, the fault’s ‘memory’ sometimes isn’t wiped out, so there’s still a good chance of having another,” said Seth Stein, the study’s senior author and the William Deering Professor of Geological Sciences in the Weinberg College of Arts and Sciences.

“As a result, a cluster of earthquakes occurs,” he said. “Earthquake clusters imply that faults have a long-term memory.”

The model shows that clusters can occur on faults with long-term memory, so that even after a big earthquake happens, the chance of another earthquake can stay high. The memory comes from the fact that the earthquake didn’t release all the strain that built up on the fault over time, so some strain remains after a big earthquake and can cause another.

“This isn’t surprising,” said Bruce D. Spencer, a professor of statistics in Weinberg and an author of the study. “Many systems’ behavior depends on their history over a long time. For example, your risk of spraining an ankle depends not just on the last sprain you had, but also on previous ones.”

Leah Salditch, lead author of the study, will present details of the research Thursday, Dec. 15, at the American Geophysical Union (AGU) meeting in San Francisco.

Since earthquake seismology started after a large earthquake destroyed San Francisco in 1906, seismologists have usually assumed that when the next big earthquake will happen on a fault depends on the time since the last one happened. In other words, a fault has only short-term memory — it “remembers” only the last earthquake and has “forgotten” all the previous ones.

This assumption goes into forecasting when future earthquakes will happen, and then into hazard maps that predict the level of shaking for which earthquake-resistant buildings should be designed.

However, Salditch, a graduate student in Stein’s research group, explained, “Long histories of earthquakes on faults sometimes show clusters of earthquakes with relatively short times between them, separated by longer times without earthquakes. For example, during clusters on the San Andreas, big earthquakes happened only about 50 years apart, while the clusters are separated by several hundred years. Clusters also have been found on the Cascadia fault system off the coast of Oregon, Washington and British Columbia, and along the Dead Sea fault in Israel.”

These results could be important for forecasting when future earthquakes will happen, said Edward M. Brooks, an author of the study and a graduate student in Stein’s research group.

“When you’re trying to figure out a team’s chances of winning a ball game, you don’t want to look just at what happened in the last game between those teams,” Brooks said. “Looking back over earlier games also can be helpful. We should learn how to do a similar thing for earthquakes.”

Note: The above post is reprinted from materials provided by Northwestern University. Original written by Megan Fellman..

As tectonic plates pull apart, what drives the formation of rifts?

At the boundaries between tectonic plates, narrow rifts can form as Earth’s crust slowly pulls apart.

But how, exactly, does this rifting happen?

Does pressure from magma rising from below ground force the land apart? Or is a rift just a rip, created mainly by the pulling motion of tectonic plates that are drifting away from each other?

A study in the journal Geology explores these questions and sheds new light on how this process works.

Past research has pointed to magma as a key driver in rifting events. But as the new findings highlight, “We have to be a bit more nuanced and acknowledge that rift processes do not have to operate identically across the entire globe,” says lead scientist Stephan Kolzenburg, Ph.D., assistant professor of geology in the University at Buffalo College of Arts and Sciences.

Study tells the story of a newly formed rift in Iceland

The new study was published in November 2021. It describes how a trench-like structure called a rift-graben opened in 2014 in Iceland near what is now known as the Holuhraun lava field, in a region that straddles the tectonic boundary between the North American and Eurasian plates. A graben forms when a chunk of land sags downward as the land on both sides of it moves away, creating a chasm called a rift.

The team concluded that in this particular case, the slow drift of tectonic plates, and not pressure from a magma chamber along the rift, was the driver.

The graben formed within a period of a few days, and then, “it just stayed like that, and it didn’t care about anything else that happened in the magmatic plumbing system,” Kolzenburg says. “The graben was remarkably stable even though lots of dynamic processes were happening underneath, such as pressure changes in the magmatic feeder system of the eruption.”

Magma leaked through the rift once it was open, but that magma didn’t appear to be the main force behind the initial creation of the rift, Kolzenburg says.

The study benefited from the work of an international group of scientists who had been closely monitoring Holuhraun and the surrounding region, documenting seismic activity and the volume of magma emerging during a period of unrest from 2014-15. Kolzenburg’s team compared this information to digital elevation models that detailed how the area’s topography changed over time, capturing the graben’s sudden appearance and tracking the landscape for nearly five years after the graben’s formation.

Not all rifts are created the same way

The findings apply specifically to the graben the team studied. In other rift zones, different dynamics may be at play, including in the Afar Region of Ethiopia, where magma is believed to play a more important role in driving rift formation, Kolzenburg says.

As he and co-authors write in their 2021 paper in Geology, “In concert, the data suggest that while some rifts may be magmatically controlled, not all rift zones require the presence of a deep-seated pressurized magma chamber to control their dynamics.”

The study was a collaboration between Kolzenburg, Julia Kubanek at the European Space Agency, Mariel Dirscherl and Ernst Hauber at the German Aerospace Center, Christopher W. Hamilton at the University of Arizona, Stephen. P. Scheidt at Howard University and Ulrich Münzer at Ludwig-Maximilians-Universität.

Reference:
S. Kolzenburg et al, Solid as a rock: Tectonic control of graben extension and dike propagation, Geology (2021). DOI: 10.1130/G49406.1

Chrysoberyl: One of the world’s most expensive Gemstone

The mineral or gemstone chrysoberyl is a beryllium aluminate with the formula BeAl2O4. The name chrysoberyl is derived from the Greekwords χρυσός chrysos and βήρυλλος beryllos, meaning “a gold-white spar”. Despite the similarity of their names, chrysoberyl and beryl are two entirely different gemstones, although they both contain beryllium. Chrysoberyl is the third hardest commonly encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8).

The ordinary chrysoberyl is yellowish-green and transparent to translucent. When the mineral has a good pale green to yellow colour and is transparent, it is used as a gemstone. The three main varieties of chrysoberyl are: ordinary yellow-green chrysoberyl, cat’s eye or cymophane, and alexandrite. Yellow-green chrysoberyl was referred to as “chrysolite” during the Victorian and Edwardian eras, which caused confusion since that name was also used for mineral olivine (‘peridot’ as a gemstone); this name is no longer used in the gemological nomenclature.

Chrysoberyl Occurrence

Chrysoberyl forms as a result of pegmatic processes. Melting in Earth’s crust produces relatively low-density molten magma, which can rise up to the surface. As the main magma body cools, the water initially present at low concentrations became more concentrated in the molten rock because it could not be incorporated into the crystallisation of solid minerals. The remaining magma thus becomes richer in water, and also in rare elements that similarly do not fit into the crystal structures of the major rock-forming minerals. Water extends the temperature range downwards before the magma becomes completely solid, allowing the concentration of rare elements to proceed to the point where they produce their own distinctive minerals. The resulting rock is igneous in appearance but formed at a low temperature by a water-rich melt, with large crystals of common minerals such as quartz and feldspar, but also with elevated concentrations of rare elements such as beryllium, lithium or niobium, often forming their own minerals; this is called pegmatite. The high water content of the magma made it possible for the crystals to grow rapidly, so that the pegmatite crystals are often quite large, increasing the likelihood of gems forming.

Chrysoberyl may also grow in country rocks near pegmatites, when pegmatite-rich be-and al-rich fluids react with surrounding minerals. It can therefore be found in mica shales and in contact with the metamorphic deposits of dolomitic marble. Because it is a hard , dense mineral that is resistant to chemical alteration, it can be wetted out of rocks and deposited in river sands and gravels in alluvial deposits with other gem minerals such as diamonds, corundum, topaz, spinel, granite and tourmaline. When found in such pleasures, there will be rounded edges instead of sharp, wedge-shaped shapes. Much of the chrysoberyl mined in Brazil and Sri Lanka is recovered from pleasure, as the host rocks have been severely weathered and eroded.

If the pegmatite fluid is rich in beryllium, beryllium or chrysoberyl crystals may form. Beryl has a high ratio of beryllium to aluminium, while the opposite is true of chrysoberyl. Both are stable with a common quartz mineral. Some chromium would also have had to be present to form alexandrite. However, beryllium and chromium do not tend to occur in the same rock types. Chromium is most common in mafic and ultramafic rocks where beryllium is extremely rare. Beryllium is concentrated in felsic pegmatites where chromium is almost absent. Therefore, the only situation where alexandrite can grow is when Be-rich pegmatite fluids react with Cr-rich country rock. This unusual requirement explains the rareness of this chrysoberyl variety.

Physical Properties of Chrysoberyl

Cleavage: {110} Distinct, {010} Imperfect, {???} Imperfect
Color: Blue green, Brown, Brownish green, Green, Gray.
Density: 3.5 – 3.84, Average = 3.67
Diaphaneity: Transparent to translucent
Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals.
Habit: Prismatic – Crystals Shaped like Slender Prisms (e.g. tourmaline).
Habit: Tabular – Form dimensions are thin in one direction.
Habit: Twinning Common – Crystals are usually twinned.
Hardness: 8.5 – Chrysoberyl
Luminescence: Non-fluorescent.
Luster: Vitreous (Glassy)
Streak: white

Geologists Day – April 3, 2022

Geologists Day takes place on the first Sunday in April every year. Finally, a day dedicated to a woefully underrated science. Without geologists, we would know nothing about the history of the earth. Earth is over 4.5 billion years old. The ground we walk on is ever-changing, always moving. Who can tell us that for certain? Geologists. Geology is a science that studies the materials, natural features, and processes found on earth. It also studies the history of all life that’s ever lived — from the time of the dinosaurs till date. Pretty incredible, right? The first Geologists Day was established by scientists in the former Soviet Union in April 1966.

HISTORY OF GEOLOGISTS DAY

Aristotle was one of the first known thinkers to make detailed observations about how the world worked. Following his footsteps, several philosophers and scientists began to dig deeper into the earth’s physical features. Eventually, the Romans learned how to mine rocks — particularly marble. Mining would literally and metaphorically build the foundations of the Roman Empire.
A new branch of study emerged during the 17th century when scientists turned to fossils to understand the earth’s history and evolution. Fossils provided new insights into the age of the earth. The debates around this concept intensified, especially between creationists and scientists. Theology said the earth was 6,000 years old. From observing fossils, scientists posited our planet was much older.

In the 19th century, geology, as we know it today, found firm ground. Scientist James Hutton proved that rocks were formed by two main processes: some because of sedimentation and others through volcanic processes. His study demonstrated that these geological activities occur slowly over thousands of years. Essentially, the present holds answers to the past. The ground we walk on today resulted from these changes and will continue to evolve long after. Hutton is called the ‘Father of Modern Geology’ for his pioneering research and discoveries.

Geology witnessed several leaps in the early 1900s with a theory called ‘Continental Drift’ by Alfred Wegener. The scientist suggested that all continents were once a supercontinent called ‘Pangaea’. Over a million years, ‘Pangaea’ broke into different pieces that drifted away from each other — taking their positions as we now know them. Today, the theory has been replaced by the science of ‘plate tectonics’ instead.

Eminent Soviet geologists established Geologists Day in April 1966. The day’s popularity ultimately crossed the borders of the former Soviet Union. Today we thank them for all their incredible research to deepen our understanding of how the world works. We hope it inspires the next generation of super geologists in the making.

NASA simulator helps to shed light on mysteries of solar system

Even in our cosmic backyard, the solar system, many questions remain open. On Venus there are formations similar to volcanoes, but it is not known if they are active. The surface of Mars suggests that there was once a vast ocean, but how it disappeared remains unclear. On the other hand, recent detections of chemical compounds that may indicate the presence of biological activity on Mars and Venus, so-called biosignatures, keep the search for life outside Earth alive. The answers may lie in the analysis of the light that reaches us from these planets, through the “fingerprints” that the molecules leave in the spectrum of that light.

In the study now published in Atmosphere, researchers from the Instituto de Astrofísica e Ciências do Espaço (Faculty of Sciences of the University of Lisbon, Portugal) compared simulations obtained with the Planetary Spectrum Generator (PSG), a planetary spectrum simulator, with observations of infrared light from the planets Venus, Mars and Jupiter.

Using PSG, developed by NASA, the team was able to explain the results of some observations and conclude that this simulator is an effective tool for studying the abundances of chemical compounds present in small amounts in planetary atmospheres.

One of the chemical compounds analyzed, methane, may originate from both biological activity and geological processes. That’s why its elusive presence on Mars, with detection by the Mars Express spacecraft and the absence of detection by the ExoMars TGO spacecraft, remains a mystery.

“By varying the parameters of our simulations, we were able to explain this detection and non-detection of methane on Mars and understand the conditions and locations in which they can occur. This is an important step towards clarifying the association of methane on Mars with the possible existence of life,” explains Pedro Machado (IA & Ciências ULisboa), co-author of this study.

NASA simulator helps to shed light on mysteries of Solar System
Geological evidence on Mars that suggests the presence of liquid water in the past. Credit: NASA

Another unknown on the red planet, also of great interest to the scientific field of the search for life outside Earth, astrobiology, is the fate of most of its water. Evidence suggests that this once flowed in abundance on the planet, and that much of the northern hemisphere was once a vast ocean. Today, Mars is an icy desert.

“Knowing the ratio between two variants of hydrogen, the deuterium isotope and simple hydrogen, helps us understand the temporal evolution of water on Mars. Deuterium is a heavy hydrogen atom, its nucleus contains one more neutron, so water, H2O, made up of a deuterium atom and a hydrogen atom, HDO, is heavier and will escape into space with more difficulty. Comparison of this ratio at a global and local level on Mars, possible with this study, gives us valuable information about the fate of Martian water,” explains João Dias (IA & Ciências ULisboa), lead author of this study.

Also included in this study, phosphine can be spontaneously produced in high pressure and temperature environments in the presence of phosphorus and hydrogen, the two chemical elements that constitute it. “This is what happens on Jupiter, with phosphine being one of those responsible for the colorful bands in the atmosphere of this gas giant,” explains Pedro Machado, “but on a rocky planet, like Earth, where these extreme conditions do not exist, its presence is associated with biological activity.”

NASA simulator helps to shed light on mysteries of Solar System
Crater in the Sirenum Fossae region on Mars, showing evidence of past water runoff. Credit: NASA/JPL/University of Arizona

So, when in 2020 a study identified phosphine in the clouds of Venus, the scientific community turned its attention to this planet. “Further studies carried out under other conditions showed that phosphine may not be present after all or be present in much smaller amounts than initially identified, something that we were also able to reproduce,” adds Pedro Machado.

Still on Venus, “sulfur dioxide is very important for us to know if there is volcanic activity. By precisely determining the abundance of this compound at different altitudes, as we have shown to be possible with PSG, we will be able to conclude about its origin,” adds João Dias.

“This work is of great importance for space missions that are now being developed, such as EnVision, Ariel, and Mars Express, from the European Space Agency (ESA), in which IA is involved, by telling us the expected values for these chemical components and allowing the instruments that are being designed for these missions to be optimized to detect within the range of expected values,” says Pedro Machado, who is a co-investigator of these missions.

NASA simulator helps to shed light on mysteries of Solar System
Illustration of Mars 4.5 million years ago showing a vast ocean in the northern hemisphere. Credit: NASA/GSFC/Rex

“In particular, missions like Ariel, which will study the atmospheres of planets orbiting stars other than the Sun, exoplanets, benefit greatly from this type of solar system studies, which can serve as a model for what we hope to be able to observe outside the solar system,” adds João Dias.

“This demonstration of the effectiveness of PSG is very important for the scientific community, and the IA is at the forefront of these studies by including in its Planetary Systems team specialists both in the study of the atmospheres of planets in the solar system and in the detection and characterization of exoplanets,” says Pedro Machado.

More information: João A. Dias et al, From Atmospheric Evolution to the Search of Species of Astrobiological Interest in the Solar System—Case Studies Using the Planetary Spectrum Generator, Atmosphere (2022). DOI: 10.3390/atmos13030461

Provided by University of Lisbon.

Volcanic activity may be the cause of marsquakes

Volcanic activity beneath the surface of Mars could be responsible for triggering repetitive Marsquakes, which are similar to earthquakes, in a specific region of the Red Planet, researchers from The Australian National University (ANU) suggest.

New research published in Nature Communications shows scientists from ANU and the Chinese Academy of Sciences in Beijing have discovered 47 previously undetected Marsquakes beneath the Martian crust in an area called Cerberus Fossae—a seismically active region on Mars that is less than 20 million years old.

The authors of the study speculate that magma activity in the Martian mantle, which is the inner layer of Mars sandwiched between the crust and the core, is the cause of these newly detected Marsquakes.

The findings suggest magma in the Martian mantle is still active and is responsible for the volcanic Marsquakes, contrary to past beliefs held by scientists that these events are caused by Martian tectonic forces.

According to geophysicist and co-author Professor Hrvoje Tkalčić, from the ANU Research School of Earth Sciences, the repetitive nature of these quakes and the fact they were all detected in the same area of the planet suggests Mars is more seismically active than scientists previously thought.

“We found that these Marsquakes repeatedly occurred at all times of the Martian day, whereas Marsquakes detected and reported by NASA in the past appeared to have occurred only during the dead of night when the planet is quieter,” Professor Tkalčić said.

“Therefore, we can assume that the movement of molten rock in the Martian mantle is the trigger for these 47 newly detected Marsquakes beneath the Cerberus Fossae region.”

Professor Tkalčić said the continuous seismicity suggests the Cerberus Fossae region on Mars is “seismically highly active.”

“Knowing that the Martian mantle is still active is crucial to our understanding of how Mars evolved as a planet,” he said.

“It can help us answer fundamental questions about the solar system and the state of Mars’ core, mantle and the evolution of its currently-lacking magnetic field.”

The researchers used data collected from a seismometer attached to NASA’s InSight lander, which has been collecting data about Marsquakes, Martian weather and the planet’s interior since landing on Mars in 2018.

Using a unique algorithm, the researchers were able to apply their techniques to the NASA data to detect the 47 previously undiscovered Marsquakes.

The study authors say while the quakes would have caused some shaking on Mars, the seismic events were relatively small in magnitude and would barely be felt if they had occurred on Earth. The quakes were detected over a period of about 350 sols—a term used to refer to one solar day on Mars—which is equivalent to about 359 days on Earth.

According to Professor Tkalčić, the Marsquake findings could help scientists figure out why the Red Planet no longer has a magnetic field.

“The Marsquakes indirectly help us understand whether convection is occurring inside of the planet’s interior, and if this convection is happening, which it looks like it is based off our findings, then there must be another mechanism at play that is preventing a magnetic field from developing on Mars,” he said.

“All life on Earth is possible because of the Earth’s magnetic field and its ability to shield us from cosmic radiation, so without a magnetic field life as we know it simply wouldn’t be possible.

“Therefore, understanding Mars’ magnetic field, how it evolved, and at which stage of the planet’s history it stopped is obviously important for future missions and is critical if scientists one day hope to establish human life on Mars.”

More information: Weijia Sun et al, Repetitive marsquakes in Martian upper mantle, Nature Communications (2022). DOI: 10.1038/s41467-022-29329-x

Journal information:Nature Communications

Provided by Australian National University

Estimates of the carbon cycle, vital to predicting climate change, are incorrect, researchers show

Virginia Tech researchers, in collaboration with Pacific Northwest National Laboratory, have discovered that key parts of the global carbon cycle used to track movement of carbon dioxide in the environment are not correct, which could significantly alter conventional carbon cycle models.

The estimate of how much carbon dioxide plants pull from the atmosphere is critical to accurately monitor and predict the amount of climate-changing gasses in the atmosphere. This finding has the potential to change predictions for climate change, though it is unclear at this juncture if the mismatch will result in more or less carbon dioxide being accounted for in the environment.

“Either the amount of carbon coming out of the atmosphere from the plants is wrong or the amount coming out of the soil is wrong,” said Meredith Steele, an assistant professor in the School of Plant and Environmental Sciences in the College of Agriculture and Life Sciences, whose Ph.D. student at the time, Jinshi Jian, led the research team. The findings are to be published Friday in Nature Communications.

“We are not challenging the well-established climate change science, but we should be able to account for all carbon in the ecosystem and currently cannot,” she said. “What we found is that the models of the ecosystem’s response to climate change need updating.”

Jian and Steele’s work focuses on carbon cycling and how plants and soil remove and return carbon dioxide in the atmosphere.

To understand how carbon affects the ecosystems on Earth, it’s important to know exactly where all the carbon is going. This process, called carbon accounting, says how much carbon is going where, how much is in each of Earth’s carbon pools of the oceans, atmosphere, land, and living things.

For decades, researchers have been trying to get an accurate accounting of where our carbon is and where it is going. Virginia Tech and Pacific Northwest National Laboratory researchers focused on the carbon dioxide that gets drawn out of the atmosphere by plants through photosynthesis.

When animals eat plants, the carbon moves into the terrestrial ecosystem. It then moves into the soil or to animals. And a large amount of carbon is also exhaled—or respirated—back into the atmosphere.

This carbon dioxide that’s coming in and going out is essential for balancing the amount of carbon in the atmosphere, which contributes to climate change and storing carbon long-term.

However, Virginia Tech researchers discovered that when using the accepted numbers for soil respiration, that number in the carbon cycling models is no longer balanced.

“Photosynthesis and respiration are the driving forces of the carbon cycle, however the total annual sum of each of these at the global scale has been elusive to measure,” said Lisa Welp, an associate professor of earth, atmospheric, and planetary sciences at Purdue University, who is familiar with the work but was not part of the research. “The authors’ attempts to reconcile these global estimates from different communities show us that they are not entirely self-consistent and there is more to learn about these fundamental processes on the planet.”

What Jian and Steele, along with the rest of the team, found is that by using the gross primary productivity of carbon dioxide’s accepted number of 120 petagrams—each petagram is a billion metric tons—the amount of carbon coming out through soil respiration should be in the neighborhood of 65 petagrams.

By analyzing multiple fluxes, the amount of carbon exchanged between Earth’s carbon pools of the oceans, atmosphere, land, and living things, the researchers discovered that the amount of carbon soil respiration coming out of the soil is about 95 petagrams. The gross primary productivity should be around 147. For scale, the difference between the currently accepted amount of 120 petagrams and this is estimate is about three times the global fossil fuel emissions each year.

According to the researchers, there are two possibilities for this. The first is that the remote sensing approach may be underestimating gross primary production. The other is the upscaling of soil respiration measurements, which could be overestimating the amount of carbon returned to the atmosphere. Whether this misestimate is a positive or negative thing for the scientifically proven challenge of climate change is what needs to be examined next, Steele said.

The next step for the research is to determine which part of the global carbon cycling model is being under or overestimated.

By having accurate accounting of the carbon and where it is in the ecosystem, better predictions and models will be possible to accurately judge these ecosystems’ response to climate change, said Jian, who began this research as a Ph.D. student at Virginia Tech and is now at Northwest A&F University in China.

“If we think back to how the world was when we were young, the climate has changed,” Jian said. “We have more extreme weather events. This study should improve the models we used for carbon cycling and provide better predictions of what the climate will look like in the future.”

As Steele’s first Ph.D. student at Virginia Tech, a portion of Steele’s startup fund went to support Jian’s graduate research. Jian, fascinated with data science, databases, and soil respiration, was working on another part of his dissertation when he stumbled across something that didn’t quite add up.

Jian was researching how to take small, localized carbon measurements from across the globe. While researching this, Jian discovered that the best estimates didn’t match up if all the fluxes of global carbon accounting were put together.

More information: Historically inconsistent productivity and respiration fluxes in the global terrestrial carbon cycle, Nature Communications (2022). DOI: 10.1038/s41467-022-29391-5
Journal information: Nature Communications
Provided by Virginia Tech

Torrential rains kill 14 in Brazil

Torrential downpours triggered flash floods and landslides across Brazil’s Rio de Janeiro state, killing at least 14 people including eight children, and leaving five missing, authorities said Saturday.

Two days of heavy rain have battered a broad swathe of the southeastern state’s Atlantic coast, the latest in a series of deadly storms in Brazil that experts say are being aggravated by climate change.

More rain is forecast for the region in the coming days.

The victims included a mother and six of her children, who were buried when a landslide swept away their home, officials said.

President Jair Bolsonaro said on Facebook the federal government had sent military aircraft to help the rescue effort and dispatched national disaster response secretary Alexandre Lucas to the state of 17.5 million people.

The new incidents come six weeks after flash floods and landslides killed 233 people in the scenic city of Petropolis, the Brazilian empire’s 19th-century summer capital, also in Rio state.

This time, the areas hit hardest included the tourist town of Paraty, a seaside colonial city known for its picturesque cobblestone streets and colorful houses.

Officials there said a landslide in the Ponta Negra neighborhood had killed a mother and six of her children, ages two, five, eight, 10, 15 and 17.

A seventh child was rescued alive and taken to the hospital, where he was in stable condition, they said.

Another four people were injured.

Six more victims, including at least two children, were killed in the city of Angra dos Reis, where officials declared a “maximum alert” and state of emergency after landslides devastated the Monsuaba neighborhood.

Several people were rescued alive, while another five remain missing, they said.

Experts say the deadly storms in Brazil, such as the one in Petropolis (people carry belongings on February 19, 2022, after a gi
Experts say the deadly storms in Brazil, such as the one in Petropolis (people carry belongings on February 19, 2022, after a giant landslide in Petropolis), are being aggravated by climate change.

Mayor Fernando Jordao said emergency workers were installing floodlights to continue the search-and-rescue operation through the night if necessary.

“Residents have been working side-by-side with us on the search,” he told a press conference.

“We’ll continue working hard.”

In Mesquita, 40 kilometers (25 miles) northwest of Rio de Janeiro city, a 38-year-old man was electrocuted trying to help another person escape the flooding, officials and media reports said.

Record rains

The storms turned streets into rivers Friday night in several cities including Rio, the state capital, sweeping up cars and triggering landslides—a frequent tragedy in the rainy season, especially in poor hillside communities.

TV channel Globo News carried images of a family evacuating two young children through the floodwaters in a styrofoam cooler in the Rio suburb of Belford Roxo, while residents posted videos on social media of small alligators swimming through flooded streets.

A hospital in the suburb of Nova Iguacu was badly flooded, turning the corridors of its intensive care unit into streams.

Officials in Angra said the city had received up to 800 millimeters (31 inches) of rain in 48 hours in some areas, “levels never before registered in the municipality.”

Experts say rainy season downpours in Brazil are being augmented by La Nina—the cyclical cooling of the Pacific Ocean—and by climate change.

Because a hotter atmosphere holds more water, global warming increases the risk and intensity of flooding from extreme rainfall.

In December, storms killed 24 people in the northeastern state of Bahia, and in January, floods and landslides claimed at least 28 lives in southeastern Brazil, mostly in Sao Paulo state.

San Andreas Fault’s creeping section could unleash large earthquakes

The central section of the San Andreas Fault could host larger quakes than previously realized.

The middle section of the San Andreas Fault may have the capacity to host larger earthquakes than previously believed.

Between the towns of Parkfield and Hollister, the famous California fault undergoes something called aseismic creep. Instead of building up strain and then slipping in one earth-rattling moment, the two sections of fault move imperceptibly, releasing stress without causing large quakes. But looking back millions of years in time, researchers have found that this section of fault may have experienced earthquakes of magnitude 7 and higher. That is larger than the magnitude-6.9 Loma Prieta temblor that killed 63 people in the Bay Area in 1989.

It’s not fully clear how long ago the large quakes on the fault occurred, but they were within the last 3 million years, said Genevieve Coffey, an earthquake geologist at GNS Science in New Zealand.

“The central section should be considered as a potential source of earthquake hazard,” Coffey told Live Science.

The San Andreas Fault

The San Andreas Fault has three sections. The southern section runs from the Salton Sea to Parkfield, California, and has the capacity for large quakes. In 1857, for example, the magnitude-7.9 Fort Tejon quake shifted the ground at the fault a whopping 29.5 feet (9 meters). The northern section of the fault runs from the town of Hollister, through the Bay Area up to Cape Mendocino, California. This section of the fault is most famous for the great 1906 San Francisco earthquake, which had an estimated magnitude of 7.9. 

In between Parkfield and Hollister, though, the fault hasn’t given rise to any recorded quakes larger than a magnitude 6. Geoscientists have dug into the fault, looking for signs in the shape of the sediment layers of long-ago earthquakes, and they haven’t found any large quakes in the last 2,000 years.

But even if the central San Andreas doesn’t build up enough stress to start a large earthquake, it could act as a conduit for quakes originating on the northern or southern section of the fault, Coffey said. She and her colleagues wanted to go back more than 2,000 years.

To do so, the researchers took advantage of the fact that when a fault slips, it generates friction, which generates heat.

“It’s like rubbing your hands together,” Coffey said.

This heat can spike the temperature of the rocks in the fault by more than 1,800 degrees Fahrenheit (1,000 degrees Celsius). And those temperature changes can change the structure of organic molecules that accumulate within sediments.

Historical quakes

The researchers analyzed a sediment core from the central San Andreas that was drilled as part of the San Andreas Fault Observatory at Depth (SAFOD) project. Deep in the core, about 1.9 miles down (3,192 to 3,196 meters), the researchers found a spot where the biomarkers showed signs of heating.

“That patch of the fault also consisted of these really highly deformed siltstones, mudstones,” Coffey said. “It had lots of these small slip layers, so lots of scaley surfaces and shiny surfaces, which is what we would think of as rocks that had hosted lots of earthquakes.”

This zone of the fault may have hosted more than 100 quakes, Coffey and her colleagues reported Feb. 25 in the journal Geology.

Next, the researchers analyzed the quake-deformed section of rock with a method called potassium-argon dating. This method takes advantage of the fact that a naturally radioactive variation of potassium, potassium-40, slowly decays into argon gas. When something happens to heat the rock, this gas is released, resetting the “potassium-argon clock” to zero. By looking at the accumulation of argon, the researchers could determine how long it had been since the rocks were heated. 

Their results suggested that the heating happened, at the earliest, 3 million years ago. But the quakes could have been far more recent, Coffey said. Part of the ongoing work done by Coffey’s collaborators involves improving the potassium-argon method for earthquake dating to narrow down that time span. However, the magnitude of the heating indicates that the central San Andreas can indeed undergo a lot of shaking — it’s likely that the earthquakes recorded in this section of the fault ranged from magnitudes in the mid-6s to low-7s, Coffey said.

“The work that we did was the first direct geologic evidence of earthquakes” in this region of the San Andreas, she said. 

The quakes probably started on the southern portion of the fault and sped along the faultline like an unzipping zipper. Knowing that the fault has this capacity is important for understanding the earthquake hazard in central California, Coffey said. 

The researchers plan to apply the potassium-argon method to other faults, including in the New Zealand bedrock, where there isn’t any organic material for traditional carbon-14 dating (which only works back to about 55,000 years) and where there are no sedimentary layers to show the marks of very old quakes. 

“The potassium-argon tool is pretty interesting, because it really gives us access to a range of faults that we haven’t been able to date in the past,” Coffey said.

Originally published on Live Science.