Researchers have discovered detectable changes in the local magnetic field that occur 2-3 days before an earthquake.
Magnetometers detected faint signals that may improve our understanding of what happens before earthquakes and offer promise for early detection.
Scientists studying intermediate to large earthquakes in California have discovered detectable changes in the local magnetic field that occur 2-3 days before an earthquake. A recent study found that the signal of the magnetic field change is faint but statistically significant, and the seismologists hope their technique can be refined to eventually help forecast earthquakes. The research was published recently in the Journal of Geophysical Research: Solid Earth.
“It’s a modest signal,” said Dan Schneider, a co-author of the study. He is the director of QuakeFinder, an earthquake research department in Stellar Solutions, a systems engineering services company. “We are not claiming that this signal exists before every earthquake, but it is very intriguing.”
The magnitude 6 South Napa earthquake in California in August 2014 caused the ground to rupture in places, including in this vineyard. Credit: U.S. Geological Survey
Although it’s always been controversial, the idea that the magnetic field may shift before earthquakes has been around for a while. The U.S. Geological Survey (USGS) states that “despite decades of work, there is no convincing evidence of electromagnetic precursors to earthquakes.”
Researchers searched data from 125 magnetometer sensor stations, like this one, that are situated along major faults in California for signals of magnetic field shifts that occurred before earthquakes. Credit: QuakeFinder
In collaboration with the Google Accelerated Science team, the scientists tapped into magnetic field data from an array of magnetometers at 125 sensor stations along major faults in California. They collected data from 2005 to 2019, during which time 19 earthquakes of magnitude 4.5 or greater occurred on the faults.
Their multistation analysis accounted for other kinds of processes that might affect the magnetometers but have nothing to do with earthquakes, such as rush hour traffic. According to Schneider, differentiating this kind of noise from potential earthquake-related signals is the biggest barrier to interpreting these data. After training their algorithms on half the data set, the researchers identified a signal indicating changes in the magnetic field between 72 and 24 hours before the earthquakes.
Schneider said that in the future, he’d like to further hone the models to eliminate more ambient noise from the magnetometers. In this study, for example, accounting for the average influence of solar activity substantially improved the results. In continuing work, the team will use remote station data to further eliminate noise due to solar activity.
The work suggests “there may be regular detectable changes in the magnetic field that with further study and isolation, could actually support the construction of a forecasting system in the future,” Schneider said.
Reference: “Case-Control Study on a Decade of Ground-Based Magnetometers in California Reveals Modest Signal 24–72 hr Prior to Earthquakes” by William D. Heavlin, Karl Kappler, Lusann Yang, Minjie Fan, Jason Hickey, James Lemon, Laura MacLean, Thomas Bleier, Patrick Riley and Daniel Schneider, 1 September 2022, Journal of Geophysical Research: Solid Earth.
DOI: 10.1029/2022JB024109
Interesting Earthquake Facts:
- The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, 1960.
- The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964,
Read original article here
California Quakes Mysteriously Preceded by Shifts in Earth’s Magnetic Field : ScienceAlert
When the next big earthquake strikes somewhere around the world, it will arrive without warning, destroying infrastructure and putting lives at risk.
Yet for days leading up to the event, titanic geological forces will already be at work, warping the crust in subtle ways that could, in theory, predict the coming catastrophe.
One possible sign could involve flickers in the magnetic field that ebbs and flows around our planet. For decades, researchers have debated the merits of hunting for magnetic signatures to imminent tremors, for want of convincing evidence.
A new case-controlled study by QuakeFinder, a humanitarian research project within systems engineering services company Stellar Solutions, in collaboration with the Google Accelerated Science team, concludes there just might be a good reason to continue the search.
Applying machine learning to ground-based measurements of local magnetic changes in the lead-up to a number of significant earthquakes across California between 2005 and 2019, the researchers found signs of a pattern that demands further study.
This isn’t to say the effect they observed could necessarily be used to predict earthquakes, but it’s nonetheless a fascinating lead for future study.
“We are not claiming that this signal exists before every earthquake,” QuakeFinder director Dan Schneider told Joshua Rapp Learn at Eos.
Yet the findings could be enough to keep the controversial topic of electromagnetic forecasts of major tremors alive for a little longer.
Premises behind hypothetical fluctuations in the magnetic field prior to earthquakes sound reasonable enough. Some argue the massive build-up of pressure in the crust prior to a quake could, in theory, change the properties of the rock layers enough to influence their conductivity.
Other studies hint at pockets of trapped gas building up prior to release creating the necessary electrical currents to affect magnetic activity.
Spotting the resulting ultra-low frequency shifts in the magnetic field would give authorities warning that something big is going to pop, providing time to prepare in the same way communities might do for a growing hurricane.
Unfortunately, what sounds like a promising idea runs into a number of obstacles in application.
For one thing, plenty of things can create low-frequency wobbles in local patches of a magnetic field. Even increases in nearby traffic or small shifts in solar activity can introduce a buzz that might be mistaken for a geological disturbance.
Unweaving a reliable signal from this noise requires having accurate measuring equipment at fixed locations near sizable tremors. Even where that occurs, enough quakes of the right size need to be recorded for a statistical sample.
With research sites located near faults all over the state of California, Quakefinder is in a solid position to overcome these hurdles.
Magnetometers buried at the different research sites provided the researchers with a sizable amount of data on quakes greater than magnitude 4.5.
After selecting quakes for which there were measurements from two close sites, and excluding pairs of sites without suitable recordings, the researchers were left with measurements on 19 earthquakes.
This sample was then divided into two groups, one serving as the basis of a machine-learning study that attempted to sift out potential patterns from known influences, with the second group serving as a test for any possible discoveries.
The signal-to-noise ratio identified by the process and confirmed in the test run wasn’t exactly strong. As the researchers admit in their published report, obvious electromagnetic anomalies prior to quakes “would have been observed, documented, and accepted much earlier” in previous investigations.
But they do suggest something intriguing is lurking in the electromagnetic shimmer like a suspicious cry in the rainstorm, one that could be present up to three days before an earthquake hits. Fine-tuning of the researchers’ method using a larger sample might be able to identify what’s going on.
Should future studies land upon a reliable hum of impending doom in the magnetic field of one area, it might still not be a universal tune, demanding even further testing at multiple sites around the globe.
For now, the idea of using tiny changes in the planet’s magnetic field to forecast tremors remains controversial. But buoyed by results like these, further investigations might finally uncover the secret whispers of a fault at breaking point.
This research was published in the Journal of Geophysical Research: Solid Earth.
Strange tsunami-like quakes shake some of the stars in our galaxy, Gaia spacecraft reveals
“Starquakes teach us a lot about stars, notably their internal workings. Gaia is opening a goldmine for ‘asteroseismology’ of massive stars,” said Conny Aerts, a professor at the Institute of Astronomy at KU Leuven in Belgium and a member of the Gaia collaboration, a group of 400 researchers that work on the data from the project, in an ESA news release.
Previously, Gaia had detected radial oscillations — motions diverging from a common point — that caused some stars to swell and shrink periodically while keeping their spherical shape. The newly discovered oscillations were non-radial.
Gaia is uniquely positioned about 930,000 miles from Earth in the opposite direction from the sun. The spacecraft carries two telescopes that can scan our galaxy from a location called the Lagrange 2, or L2, point. At this point, the spacecraft is able to remain in a stable spot due to the balance of gravitational forces between Earth and the sun.
This also means that the spacecraft doesn’t have any interference from Earth’s light, and it can use the minimum amount of fuel to remain in a fixed position. The vantage point allows Gaia to have unfettered views and continuously scan our galaxy.
Much of the latest information about the Milky Way was revealed by Gaia’s newly released spectroscopy data, resulting from a technique in which the starlight is split into its constituent colors, like a rainbow.
The data gathered by Gaia includes new information on the chemical composition, temperatures, mass, and age of stars, as well as the speed at which they move toward or away from Earth. Detailed information about more than 150,000 asteroids in our solar system and space dust — what lies between stars — was also released.
“Gaia’s chemical mapping is analogous to sequencing the DNA of the human genome,” said George Seabroke, a senior research associate for the Mullard Space Science Laboratory at University College London, in a statement from the Royal Astronomical Society.
“The more stars we know the chemistry for, the better we can understand our galaxy as a whole. Gaia’s chemical catalogue of six million stars is ten times larger than previous ground-based catalogues, so this is really revolutionary. Gaia’s data releases are telling us where stars were located and how they are moving. Now we also know what a lot of these stars are made of,” Seabroke said.
“Unlike other missions that target specific objects, Gaia is a survey mission,” said Timo Prusti, project scientist for Gaia at ESA.
“This means that while surveying the entire sky with billions of stars multiple times, Gaia is bound to make discoveries that other more dedicated missions would miss,” Prusti said. “This is one of its strengths, and we can’t wait for the astronomy community to dive into our new data to find out even more about our galaxy and its surroundings than we could’ve imagined.”
‘Monster’ Quake on Mars Is The Biggest Ever Recorded on Another Planet, NASA Says
In terms of seismic events on the red planet (or indeed any other planet besides Earth), this is the biggest one recorded so far: the NASA InSight lander has recorded a ‘monster’ of a marsquake, which is estimated to have hit magnitude 5 on the scale used on Earth.
That beats the previous record holder, a magnitude-4.2 marsquake that Insight recorded back on 25 August 2021. The new quake happened on Mars on May 4 of this year, the 1,222nd sol (or Martian day) of the lander’s mission.
A magnitude-5 quake on Earth would be classed as moderate, only causing minor damage. However, it’s right at the upper end of the size of quakes that scientists are discovering on Mars, due to less seismic activity.
The full marsquake spectrogram. (NASA/JPL-Caltech/ETH Zurich)
Right now we don’t know what caused the marsquake or where exactly on the red planet it originated from, but it’s already of intense interest for researchers. It adds to the more than 1,300 quakes that Insight has detected since landing in November 2018.
By studying the seismic waves traveling across Mars, scientists hope to learn more about the planet’s crust, mantle, and core. That in turn should inform understanding about how Mars (and other similar planets, such as Earth) formed in the first place.
“Since we set our seismometer down in December 2018, we’ve been waiting for ‘the big one’,” says planetary geophysicist Bruce Banerdt from the Jet Propulsion Laboratory (JPL) in California, and the leader of the InSight mission.
“This quake is sure to provide a view into the planet like no other. Scientists will be analyzing this data to learn new things about Mars for years to come.”
As marsquakes aren’t typically as violent as earthquakes, they’re more difficult to detect, and other vibrations – from the wind, for example – can interfere with readings. With that in mind, InSight is fitted with a highly sensitive seismometer called the Seismic Experiment for Interior Structure.
Volcanic activity is also thought to be generating seismic waves on Mars, and experts continue to identify new patterns in the data that Insight and its seismometer have already logged and beamed back to Earth.
With that in mind, you can expect to hear plenty more about the data collected by Insight on 4 May 2022, in the future, but for now it’s clear that the quake is a record-breaker – and way above average for what would normally be expected on Mars.
Unfortunately, Insight has now run into some technical difficulties: With the onset of the Martian winter and increased levels of dust in the air, the lander is struggling to get enough sunlight on the solar panels that power it up.
As a result, the machine has put itself into safe mode for the time being. This hibernation shuts down all but the most essential functions, and it may be some time before we hear anything from Insight again.
Record-Breaking Earthquake Swarm Hits Antarctica as Sleeping Volcano Awakens
A long-dormant underwater volcano near Antarctica has woken up, triggering a swarm of 85,000 earthquakes.
The swarm, which began in August 2020 and subsided by November of that year, is the strongest earthquake activity ever recorded in the region. And the quakes were likely caused by a “finger” of hot magma poking into the crust, new research finds.
“There have been similar intrusions in other places on Earth, but this is the first time we have observed it there,” study co-author Simone Cesca, a seismologist at the GFZ German Research Centre for Geosciences in Potsdam, told Live Science.
“Normally, these processes occur over geologic time scales,” as opposed to over the course of a human lifespan, Cesca said. “So in a way, we are lucky to see this.”
The swarm occurred around the Orca Seamount, an inactive volcano that rises 2,950 feet (900 meters) from the seafloor in the Bransfield Strait, a narrow passage between the South Shetland Islands and the northwestern tip of Antarctica.
In this region, the Phoenix tectonic plate is diving beneath the continental Antarctic plate, creating a network of fault zones, stretching some portions of the crust and opening rifts in other places, according to a 2018 study in the journal Polar Science.
Scientists at the research stations on King George Island, one of the South Shetland Islands, were the first to feel the rumblings of small quakes. Word soon got back to Cesca and his colleagues around the world, some of whom were collaborating on separate projects with the researchers on the island.
The team wanted to understand what was going on, but King George Island is remote, with just two seismic stations nearby, Cesca said. So the researchers used data from those seismic stations, as well as data from two ground stations for the global satellite navigation system, to measure ground displacement.
They also looked at data from more far-flung seismic stations and from satellites circling Earth that use radar to measure shifting at ground level, the study authors reported April 11 in the journal Communications Earth & Environment.
The nearby stations are rather simple, but they were good for detecting the tiniest quakes. More distant stations, meanwhile, use more sophisticated equipment and can thus paint a more detailed picture of the larger quakes.
By piecing these data together, the team was able to create a picture of the underlying geology that triggered this massive earthquake swarm, Cesca said.
The two largest earthquakes in the series were a magnitude 5.9 quake in October 2020 and a magnitude 6.0 quake in November. After the November quake, seismic activity waned. The quakes seemed to move the ground on King George Island around 4.3 inches (11 centimeters), the study found.
Only 4 percent of that displacement could be directly explained by the earthquake; the scientists suspect the movement of magma into the crust largely accounts for the dramatic shifting of the ground.
“What we think is that the magnitude 6 somehow created some fractures and reduced the pressure of the magma dike,” Cesca said.
If there was an underwater eruption at the seamount, it likely happened at that time, Cesca added.
But as of yet, there is no direct evidence for an eruption; to confirm that the massive shield volcano blew its top, scientists would have to send a mission to the strait to measure the bathymetry, or seafloor depth, and compare it to historical maps, he said.
Related content:
Deepest earthquake ever detected should have been impossible
This article was originally published by Live Science. Read the original article here.
Mars Is Rumbling With Mysterious Quakes We’ve Never Detected Before
It turns out that Mars is rumblier than we knew. New techniques have revealed previously undetected quakes beneath the Martian surface – and, scientists say, the best explanation so far is ongoing volcanic activity.
The evidence seems to be mounting that Mars is far from dead, but hosts, underneath its dusty, barren surface, an interior gurgling away with seismic activity.
“Knowing that the Martian mantle is still active is crucial to our understanding of how Mars evolved as a planet,” says geophysicist Hrvoje Tkalčić of the Australian National University in Australia.
“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.”
For a very long time, scientists believed that nothing much was going on inside Mars.
The planet has very little in the way of a magnetic field. Planetary magnetic fields are (usually) generated inside the planet, by something called a dynamo – a rotating, convecting, and electrically conducting fluid that converts kinetic energy into magnetic energy, spinning a magnetic field out into space.
Mars’ lack of a magnetic field suggests a lack of activity. This is a big deal; in fact, a magnetic field can mean the difference between life and death. Here on Earth, the magnetic field protects us from cosmic radiation that might destroy life. On Mars, radiation levels are much higher, even though it is more distant from the Sun.
“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,” Tkalčić explains.
But when NASA’s InSight lander arrived in November 2018 and started listening for Mars’ heartbeat, we learnt something really remarkable: Mars is rumbling. To date, InSight has detected hundreds of marsquakes – enough to give us a detailed map of the Martian interior.
Tkalčić and his colleague, geophysicist Weijia Sun of the Chinese Academy of Sciences, wanted to look for quakes that might have gone unnoticed in the InSight data. They used two unconventional techniques, only recently applied to geophysics, to hunt seismic events in the InSight data.
Based on nine templates of known marsquakes, the pair detected 47 new seismic events, coming from a region on Mars called the Cerberus Fossae – a system of fissures created by faults that have pulled the crust apart.
Most of those new seismic events resemble the waveforms of two notable Cerberus Fossae quakes that took place in May and July of 2019, suggesting that the smaller quakes are related to the larger ones.
Then the researchers sought to figure out the cause of the quakes. Their analysis found that there was no pattern to be found in the timing of the quakes, ruling out causes such as the influence of Martian moon Phobos.
“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,” Tkalčić says.
“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.”
Previous analysis of features on the surface of Mars at the Cerberus Fossae found that the region had been volcanically active recently, within the last 10 million or so years.
The activity identified by Sun and Tkalčić, attributed to the repetitive movement of magma in the Martian mantle, also suggests that Mars is more volcanically and seismically active than we thought.
If this is the case, the results have implications for our understanding of the history of Mars – and its future.
“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,” Tkalčić says.
“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.”
The research has been published in Nature Communications.
Bouncing Boulders Point to Quakes on Mars
If a rock falls on Mars, and no one is there to see it, does it leave a trace? Yes, and it’s a beautiful herringbone-like pattern, new research reveals. Scientists have now spotted thousands of tracks on the red planet created by tumbling boulders. Delicate chevron-shaped piles of Martian dust and sand frame the tracks, the team showed, and most fade over the course of a few years.
Rockfalls have been spotted elsewhere in the solar system, including on the moon and even a comet. But a big open question is the timing of these processes on other worlds — are they ongoing or did they predominantly occur in the past?
A study of these ephemeral features on Mars, published last month in Geophysical Research Letters, says that such boulder tracks can be used to pinpoint recent seismic activity on the red planet. This new evidence that Mars is a dynamic world runs contrary to the notion that all of the planet’s exciting geology happened much earlier, said Ingrid Daubar, a planetary scientist at Brown University who was not involved in the study. “For a long time, we thought that Mars was this cold, dead planet.”
To arrive at this finding, Vijayan, a planetary scientist at the Physical Research Laboratory in Ahmedabad, India who uses a single name, and his colleagues pored over thousands of images of Mars’s equatorial region. The imagery was captured from 2006 through 2020 by the High Resolution Imaging Science Experiment (HiRISE) camera onboard NASA’s Mars Reconnaissance Orbiter, and revealed details as small as 10 inches across.
“We can discriminate individual boulders,” Dr. Vijayan said.
The team manually searched for chain-like features — a telltale signature of a rock careening down an incline — on the sloped walls of impact craters. Dr. Vijayan and his collaborators spotted more than 4,500 such boulder tracks, the longest of which stretched over a mile and a half.
Sometimes the tracks change direction and occasionally new tracks suddenly branch off, Dr. Vijayan said. Such changing tracks are likely evidence that a boulder disintegrated mid-fall and that its offspring continued bouncing downslope.
Roughly one third of the tracks the researchers studied were absent in early images, meaning that they must have formed since 2006. The bounce marks of all of these young tracks are framed by a chevron-shaped pile of Martian regolith. That material, which Dr. Vijayan and his colleagues nicknamed “boulder fall ejecta,” is kicked out each time a boulder impacts the surface, the researchers propose.
And that boulder fall material is transient: By tracing the same tracks in images obtained at different times, the team found that boulder fall ejecta tends to remain visible for only about four to eight years. The researchers suggest that winds continuously sweeping over the surface of Mars redistribute dust and sand and erase the ejecta.
Because boulder fall ejecta fades so rapidly, seeing it implies that a boulder was dislodged recently, the team suggest. And a common cause of rockfalls, on Earth and elsewhere, is seismic activity.
Dr. Vijayan and his collaborators found that roughly 30 percent of the boulder tracks in their sample with boulder fall ejecta were concentrated in the Cerberus Fossae region of Mars. That’s far more than expected, the researchers say, since this region encompasses only 1 percent of the study’s area. “The surrounding craters have lots of boulder falls,” Dr. Vijayan said. “A few of them even have multiple falls in the same location.”
That makes sense, said Alfred McEwen, a planetary geologist at the University of Arizona and the principal investigator of HiRISE, not involved in the research. The geography near Cerberus Fossae, namely the Tharsis volcanic region, predisposes the area to seismic activity. “These giant masses of dense rock loaded up on the surface creates stresses throughout the surrounding crust of Mars,” Dr. McEwen said.
Since 2019, hundreds of marsquakes have been detected by NASA’s InSight lander, and two of the largest occurred last year in the Cerberus Fossae region.
In the future, Dr. Vijayan and his collaborators plan to extend their analysis to Mars’s polar regions. The HiRISE camera will hopefully oblige, Dr. McEwen said, despite the instrument being significantly past its design lifetime. “HiRISE is still going strong.”
Here’s Why Earthquakes’ ‘Four-Leaf Clover’ Shockwaves Are Dangerous Instead of Lucky
Geologists have measured a devastating ‘four-leaf clover’ pattern of earthquake shockwaves in greater detail than ever before – and the resulting findings could be crucial in making our buildings and cities more resistant to large quakes in the future.
This four-pronged pattern has been analyzed before, but never in as much depth as this. The team behind the new study is hoping that it might remove some of the mystery surrounding how earthquake shockwaves spread out across different frequencies.
Crucially, the cloverleaf shockwaves spread at low frequencies of under 10 hertz, a level of vibration that many buildings and structures are particularly vulnerable to.
The four-leaf clover pattern is visible at lower frequencies. (Trugman et al., Geophysical Research Letters, 2021)
“We find that at low frequencies, a simplified and widely used four-lobed model of earthquake ground motions does a good job describing the observed seismic wavefield,” write the researchers in their published paper.
“At higher frequencies, however, this four-lobed radiation pattern becomes less clear, deteriorating due to complexity in earthquake source processes and fault zone structure.”
The researchers looked at data from one of the densest seismic arrays on the planet: the LArge-n Seismic Survey in Oklahoma (LASSO), which is made up of 1,829 seismic sensors within an area of just 15 by 20 miles (25 by 32 kilometers).
LASSO was used to measure P-wave data from 24 small earthquakes across a period of 28 days in 2016, and it’s this data that the new study digs into. Having sensors so close to the epicenter of the quakes meant that patterns could be spotted before they smoothed out and evened off over greater distances.
By using algorithms to filter shockwaves by frequency, the four-leaf clover pattern emerged, but only at the lower frequencies. That might be because lower frequency seismic waves can bypass the jumble of broken rock found at earthquake faults, rather than being reflected and scattered in many different directions.
“What happens when you have an earthquake is that pieces of broken rock inside the fault zone start to move around like pinballs,” says geophysicist Victor Tsai, from Brown University in Rhode Island.
The earthquakes recorded by the LASSO array were relatively small – barely perceptible to the sensors – but the same patterns should be repeated across stronger quakes, the researchers predict. The next step is to put that to the test.
Ultimately, new data like this can make earthquake assessments and modeling more accurate. It shows that while people on the ground might experience a consistent level of shockwaves (the higher frequency ones), the buildings around them might be under a greater or lesser level of stress (the lower frequency shockwaves), depending on where they are in the four-leaf clover pattern.
While earthquake faults vary in terms of their age, their geological composition, and other factors, the underlying physics should be the same. The scientists are hoping to put together a catalog of earthquake zones, showing the faults with the most potential for dangerous seismic waves and resulting damage.
“What’s important in these results is that close to the source we’re seeing a variation in ground motion, and that’s not accounted for in any sort of hazard model,” says the study’s first author, earthquake geophysicist Daniel Trugman from the University of Texas at Austin.
The research has been published in Geophysical Research Letters.
NASA’s InSight lander has finally detected 3 big Mars quakes, including one that lasted nearly 90 minutes
NASA’s Insight lander was sitting silently in the empty dust plains of Mars on Saturday, as it had for the past 1,000 Martian days, when the ground began to rumble.
The shaking continued for nearly an hour and a half.
The robot beamed the data from its seismometer back to Earth, and NASA scientists realized they had what they’d been waiting for: a big quake. Insight had recorded a magnitude 4.2 Mars quake – the kind NASA scientists had been wanting to observe since Insight touched down on the red planet in November 2018.
Two other big ones recently rolled through, too: On August 25, the lander felt two quakes of magnitudes 4.2 and 4.1.
Before these, the biggest quake the lander had felt was a 3.7 in 2019.
“It looks like there are fewer large quakes on Mars, relative to the number of small quakes, than we would expect. It’s a little bit puzzling,” Bruce Banerdt, the principal investigator for InSight, told Insider in April.
But the Saturday quake was five times more energetic than the 3.7-magnitude rumble.
These big quakes offer a missing piece of the Martian puzzle. Scientists can use their seismic waves to learn about the makeup of Mars’ core, in the same way the waves of an X-ray or CAT scan are used in the body. Getting more detailed views into Mars’ insides can yield clues about how the planet was born and how it has evolved over time. That knowledge could be crucial in astronomers’ efforts to find other worlds that might host life.
“By looking at Mars’ core and looking at Mars’ crust, and understanding that these haven’t changed very much in the last 4.5 billion years, we can get a glimpse into what the Earth might have looked like very early on,” Banerdt said in April. “Mars is helping us to understand just how rocky planets form and how they evolve in general.”
Mars quakes have revealed an Earth-like planet with a moon-like crust
InSight has detected more than 700 quakes in total, and they’ve revealed a lot about the planet’s interior already. Scientists have learned that Mars’ crust is thinner than they thought, and that it’s more like the moon’s crust than Earth’s – it’s broken up from asteroid impacts.
Because the Martian crust is so dry and broken, its quakes last much longer than earthquakes. They reverberate between cracks in the crust, and there’s not as much moisture to absorb them. So the quakes InSight has felt have typically lasted 10 to 40 minutes.
Recently, scientists have also used the quakes to determine that Mars has a molten core. They’re not yet sure whether a solid inner core hides beneath a molten outer core, the way it does on Earth.
NASA creatively solved an energy crisis to keep InSight’s seismometer on
InSight almost had to shut down its seismometer earlier this year. The robot was experiencing an energy shortage because dust was building up on its solar panels.
Among NASA’s other Mars robots, big gusts of wind have whooshed through regularly enough to clear dust off the solar panels. But the plains where InSight sits turned out to be abnormally still.
Then to make matters worse, Mars was entering the coldest part of its year during our spring and summer, when the red planet got the furthest from the sun in its oval-shaped orbit. That meant InSight would need to funnel even more energy into its heaters to survive.
So NASA decided to put InSight into hibernation. In February, the lander began incrementally shutting off its scientific instruments in order to conserve power to keep itself warm. In June, the team was preparing to shut down the seismometer, and Banerdt told a NASA group that the lander’s life might not last past April 2022, according to SpaceNews.
But then the InSight team crafted an ingenious way to clean off the solar panels. They instructed the robot to scoop up dirt and slowly trickle it next to the panels. Some of the large grains of sand got caught in the wind, bounced off the solar panels, and took some stubborn dust with them – enough to add about 30 watt-hours to Insight’s daily energy production after the first attempt.
They carried out that process several more times in order to ensure a steady enough power supply to keep the seismometer running through June and July, when Mars started swinging back towards the sun.
“If we hadn’t acted quickly earlier this year, we might have missed out on some great science,” Banerdt said in a press release.
Read the original article on Business Insider
Los Angeles rocked by 4.3-magnitude earthquake days after smaller quakes
A preliminary 4.3-magnitude earthquake rocked the Los Angeles area on Friday evening.
The quake was centered in Carson, south of downtown, but was felt across Los Angeles County — as far northeast as Victorville and as far south as the U.S.-Mexico border, according to the U.S. Geological Survey’s “Did You Feel It” site.
The airport said in a statement that operations crews were checking the airport and airfield after the quake but no damage had been discovered.
The earthquake had a depth of about 9 miles and followed two other smaller quakes within the last week-and-a-half that were 3.0 or higher.
LOS ANGELES EARTHQUAKE MEASURED AT 3.0
Los Angeles usually has around five quakes of 4.0 to 5.0 each year.
“This size happens on average somewhere in Southern California every couple of months,” seismologist Lucy Stone told KCBS-TV, according to the Los Angeles Times. “When it happens to be in the middle of the Los Angeles basin then a lot more people feel it and it becomes bigger news.”
While some people on social media had reported a fire or an explosion at a refinery in Carson along with photos of flames shooting up, the Los Angeles Sheriff’s Department in Carson said on Twitter a “controlled flaring event” is happening at the plant to burn off excess gases and no structural damage has been reported from the quake.
The flaring was conducted after the plant lost power, a spokesman for the Marathon Petroleum refinery told the Times.
“Whatever is going on is a normal procedure,” a supervisor told the newspaper.
CLICK HERE TO GET THE FOX NEWS APP
No damage has been reported in the county.