A basic and accurate scheme, but that nevertheless leaves out other subtler layers that scientists are now beginning to identify in the deep interior of our planet.
A team of geologists has detected a previously unknown layer in the middle of the Earth’s mantle, whose characteristics are reminiscent of those of the planet’s surface.
A new study published in the Journal of Science, authored by geophysicists Jessica Irving and Wenbo Wu of Princeton University, in collaboration with Sidao Ni of the Institute of Geodesy and Geophysics of China, describes how researchers used data from the seismic waves of a large earthquake in Bolivia to locate, at a depth of 660 kilometers, a new region inside the Earth, one that has left them speechless: it features a mountain range, and plains, very similar to those on the surface of our planet.
And to be able to peer deep inside the planet, researchers had to make use of the most powerful waves that exist on our planet, the seismic waves generated by massive earthquakes.
“You want a big, deep earthquake to get the whole planet to shake,” said Irving, an assistant professor of geosciences.
For this particular study, the key data were obtained from seismic waves captured after an 8.2 magnitude earthquake, the second most powerful ever recorded, which shook Bolivia in 1994.
“Earthquakes this big don’t come along very often,” Irving said.
“We’re lucky now that we have so many more seismometers than we did even 20 years ago. Seismology is a different field than it was 20 years ago, between instruments and computational resources.”
But data alone is nothing if you don’t know how to make use of it.
That’s why scientists used the group of Tiger supercomputers from Princeton University to simulate the complex behavior of scattered seismic waves in the depths of the Earth.
The technology applied for this analysis depends almost entirely on a single property of the waves: its ability to bend and bounce.
Thus, in the same way, that light waves can bounce (reflect) in a mirror or bend (refract) when they pass through a prism, seismic waves travel directly through homogeneous rocks but are reflected or refracted when finding limits or roughness.
“We know that almost all objects have surface roughness and therefore scatter light,” said Wu, the lead author on the new paper, who just completed his geosciences Ph.D. and is now a postdoctoral researcher at the California Institute of Technology.
“That’s why we can see these objects — the scattering waves carry the information about the surface’s roughness. In this study, we investigated scattered seismic waves traveling inside the Earth to constrain the roughness of the Earth’s 660-km boundary.”
Scientists were left stunned by the roughness of the boundary. As they explain, its rougher than the surface layer we live on.
“In other words, stronger topography than the Rocky Mountains or the Appalachians exist at the 660-km boundary, explained Wu.
While the new study undoubtedly describes one of the most sensational discoveries made beneath our feet, their statistical model doesn’t offer much insight that could allow precise height determinations.
Nonetheless, scientists say that there’s a chance that some of these underground mountains are larger than anything we’ve seen on the surface of the planet.
They say that the roughness wasn’t equally distributed, either. According to scientists, just as the crust’s surface has smooth ocean floors and massive mountains, the 660-km boundary beneath our feet has rough areas and smooth patches.
A new study published in the Nature Scientific Reports on July 13 suggests that powerful eruptions on the Sun can trigger large earthquakes on Earth. In the paper, the authors analyzed 20 years of proton density and velocity data, as recorded by the SOHO satellite, and the worldwide seismicity in the corresponding period, as reported by the ISC-GEM catalogue. They found a clear correlation between proton density and the occurrence of large earthquakes (M > 5.6), with a time shift of one day.
The Sun may seem relatively docile, but it is constantly bombarding the solar system with energy and particles in the form of the solar wind.
Sometimes, eruptions on the Sun’s surface cause coronal mass ejections that hurtle through the solar system at extremely fast rates.
The new study suggests that particles from eruptions like this may be responsible for triggering groups of powerful earthquakes.
“Large earthquakes all around the world are not evenly distributed– there is some correlation among them,” said co-author Giuseppe De Natale, research director at the National Institute of Geophysics and Volcanology in Rome, Italy.
“We have tested the hypothesis that solar activity can influence the worldwide [occurrence of earthquakes].”
Scientists noted a pattern in some massive earthquakes around the planet– they tend to occur in groups, not randomly. This indicates that there may be some global phenomenon triggering these worldwide tremors.
To address this, researchers searched through 20 years of data on both earthquakes and solar activity– specifically from NASA-ESA’s Solar and Heliospheric Observatory (SOHO) satellite– seeking any probable correlations.
Image credit: NASA/SDO
SOHO, located about 1.45 million km (900 000 miles) from our planet, monitors the Sun, which helps scientists track how much solar material strikes the Earth.
By comparing the ISC-GEM Global Instrumental Earthquake Catalogue– a historical record of powerful tremors– to SOHO data, the researchers noticed more strong earthquakes happened when the number and velocities of incoming solar protons increased.
When protons from the Sun peaked, there was also a spike in earthquakes above M5.6 for the next 24 hours.
“This statistical test of the hypothesis is very significant,” said De Natale. “The probability that it’s just by chance that we observe this, is very, very low– less than 1 in 100 000.”
After noticing there was a correlation between solar proton flux and strong earthquakes, the researchers went on to propose a mechanism called the reverse piezoelectric effect.
Compressing quartz rock, something common in the Earth’s crust, can produce electrical pulse through a process called the piezoelectric effect. The researchers think that such small pulses could destabilize faults that are nearing rupture, triggering earthquakes. Signals from electromagnetic evens, such as earthquake lightning and radio waves, have been recorded occurring alongside quakes in the past.
Some scientists think these events are caused by the quakes themselves, but other studies have spotted strong electromagnetic anomalies before huge earthquakes and not after, so the exact nature of the correlation of earthquakes and electromagnetic fields is still debated.
Meanwhile, this new explanation suggests that electromagnetic anomalies are not the result of earthquakes, but cause them instead. As positively charged protons from the Sun hit the Earth’s magnetic bubble, they generate electromagnetic currents that propagate across the world. Pulses created by these currents go on to deform quartz in the crust, ultimately triggering earthquakes.
Large earthquakes occurring worldwide have long been recognized to be non Poisson distributed, so involving some large scale correlation mechanism, which could be internal or external to the Earth. Till now, no statistically significant correlation of the global seismicity with one of the possible mechanisms has been demonstrated yet. In this paper, we analyze 20 years of proton density and velocity data, as recorded by the SOHO satellite, and the worldwide seismicity in the corresponding period, as reported by the ISC-GEM catalogue. We found clear correlation between proton density and the occurrence of large earthquakes (M > 5.6), with a time shift of one day. The significance of such correlation is very high, with probability to be wrong lower than 10–5. The correlation increases with the magnitude threshold of the seismic catalogue. A tentative model explaining such a correlation is also proposed, in terms of the reverse piezoelectric effect induced by the applied electric field related to the proton density. This result opens new perspectives in seismological interpretations, as well as in earthquake forecast.
Seismologists from the United States Geological Survey (USGS) have found previously unknown undersea faults near the epicenters of earthquakes in Puerto Rico. The findings will help seismologists develop a clearer picture of tectonic activity in the area and give the public a clearer sense of the potential for future tremors.
In a news release published by the USGS, the agency announced that seafloor faults may have triggered the previous earthquake series on the island, which began December 28, 2019, including an M6.4 on January 7, 2020.
Earthquakes in southern Puerto Rico – May 2020. Credit: TW/SAM, Google. Data source: USGS
USGS said their seismologists were not surprised by the fact that earthquakes occurred but by where they occurred.
Puerto Rico lies on an active boundary between the Caribbean and North American plates, with the northeast corner of the Caribbean plate moving eastward about two centimeters (less than an inch) per year along a strike-slip fault. There is geologic evidence of earthquakes that probably took place millennia ago, while history records earthquakes and tsunamis in Puerto Rico as far back as the 1500s. But most seismic activity has been on the north side of the island, not the south side, where previously unknown undersea faults may have triggered this latest earthquake series.
“It seemed likely that a previously unknown fault system off the south coast was involved in the earthquake sequence, and there should be evidence of that on the seafloor,” said Uri ten Brink, a USGS research geophysicist.
“We thought that if that were true, the information would be potentially very valuable to science, and to the people of southern Puerto Rico. They are still recovering from the effects of Hurricane Maria, and now they are facing a completely different type of hazard, and they are hungry for information about it.”
Ten Brink, along with scientists from the University of Puerto Rico Mayaguez, ran a sequence of one-day research cruises out of the University of Puerto Rico Marine Station in La Parguera from March 7 to 13.
Preliminary findings confirm ten Brink’s assumptions that there is proof of at least one underwater fault in Guayanilla Bay, which might be an extension of a fault mapped previously on land.
Several more faults had been tentatively identified lying 7 and 15 km (4 and 9 miles) offshore, in waters up to about 1 000 m (3 300 feet) deep, also within areas identified as the epicenters of some of the latest earthquakes.
Locations of multichannel seismic reflection profiles (in black), collected during cruise FA2020-14. Image credit: Uri ten Brink, USGS
The team towed a device called “sparker” to map the faults, which uses an electrical charge to produce an air bubble in the sea. When the bubble expands, it generates a sound wave that travels through water and into the seabed, where geologic layers reflect some of the energy back to the surface. The research vessel also towed an array of 32 hydrophones below the sea surface to spot pressure changes underwater.
By measuring differences in the signals’ return, researchers can identify differences in the elevation of the rock beneath the seafloor. The differences, called offsets, are considered to be indications of faults that have been active recently.
The USGS team collected about 250 km (155 miles) of seismic reflection data, imaging the seabed and underwater structures at resolutions of just a few meters.
From the ship, several fresh scars were identified in shore-facing cliffs from Punta Montalva to Guayanilla Bay, which was caused likely by rockfalls due to the powerful tremors.
The team also searched for evidence of a fault breaking the seafloor at Punta Montalva, but the seismic data do not indicate clearly such a fault at first look.
Ten Brink said that in the following months, more sophisticated data processing is likely to unveil more faults, and the team expects to be able to measure ruptures along the faults.
“This data will eventually help seismologists develop a clearer picture of tectonic activity in the area,” he remarked. “Ultimately, we hope the USGS’ work in this region will help give the public a clearer sense of the potential for future earthquakes.”
“The USGS’ research findings are being used to improve building codes that will help Puerto Rico better withstand future earthquakes and to better prepare for tsunamis.”
With huge spikes in the Schumann Resonance-Earth’s heartbeat-plus the largest solar flare since 2017, the triple June/July eclipse gateway is now wide open and already the seismic ripples are palpable. June 5th delivers a penumbral lunar eclipse on a sensitive point in the June 4 – July 22 Mercury Max cycle with a strong geophysical shock window between June 1 – 8.
Watch for seismic activity, including solar flares, earthquakes and volcanic eruptions. The increased magnetics can fritz your nervous and etheric systems, so to avoid feeling tired but wired, drink extra water and stay grounded by getting outside into nature. In the 3D world, people will react on a hair trigger- as in the protests and riots in the USA where the eclipses are shining a spotlight on racial injustice
Eclipses have a reach of 4 weeks before and 6 months after the event itself, so watch for unpredictable sideways elevators to start shifting you quickly you from one set of life circumstances into another.
For the first time since December 14 2001 – November 23 2003 – whichever aspect of your life is symbolised by Gemini/Sagittarius is going to experience 7 wild card eclipses during 2020/21. The nature of the collective karmic chickens coming home to roost is shifting dramatically as is your new mission…. away from total obsession with personal security, belonging and sanctuary towards progressive thinking and problem solving.
This is a much needed re-calibration of Mind- of synthesizing data into practical wisdom, a harbinger of the approaching historic zeitgeist shift from Earth to Air. Earth values – materialism, consumerism, money, science – will be gradually replaced with Air values – intellect, information, collaboration, multi-dimensional understanding of the world.
Click image to view full-sized chart.
The Chandra Symbol for Lunar Eclipse 15 Sagittarius:
A Tidal Wave Approaching
“The momentum of collective events runs toward floodtide when there is a major transition from one whole cycle to another. The personal life stream runs in similar patterns. When you’re getting ready to take off in a whole different direction, there is first a transition that is both immensely exciting and fantastically disturbing. You feel just about swept away by the oncoming changes and just before they really get going, the tension, the pressure, and the strain can tear you apart. You want to go with it, yet you yearn for sanctuary. This keen ambivalence gets loaded with desire, anticipation, memory pictures, and utopian visions. The mix is volatile. Learning how to ride this wave is such a great endeavour that it, in itself, becomes what it is all about. The consummate opportunity to open wide, but stay substantively firm and concentrated. Mastery or bust. The infinite future or wipe-out. A spine-tingler all the way.” From Inside Degrees Elias Lonsdale
This is the first lunar eclipse across the Sagittarius South Node of Fate/Gemini North Node of Fate since May 2002. Think back to that time to decipher the threads in your own life. It is conjunct the karmic Great Attractor whose strapline is: On the Wavelength of the Creator’s Voice. It’s a very intense point that has mystical and metaphysical properties-the seat of the Universal Source and cosmic balance.
If you have planets or points between 11 to 21 degrees of Gemini, Virgo, Sagittarius or Pisces, that part of your life will be shaken awake. Eclipses are some of the most dramatic tools that the universe uses to get you to pay attention to areas in your life that need to change. They work very rapidly – often in a blink of an eye switching off an old life, defragging you and rebooting you.
This extremely karmic South Node eclipse will change circumstances outside your control, pushing you to clear old karma, to break the chains of old toxic habits and cause and effect. Relationships could get real very quickly and the truth laid bare.
Coda: Switch your B.S. detector on to a high setting – you’re going to need it on your new Gemini Mission!
For much more on how the 3 June/July eclipses will fast track you into phase 2 embodiment and change your way of living and working ,sign up to my 5D Report:” Another Roll of the Eclipse Dice”.
Aries Weekly Forecast: May 31-June 7, 2020
This is going to a super intense week when as a Fire sign, you are going to feel as if you’re combusting. The seismic window is active between June 1-8th and June 5th’s wild card Full Moon eclipse falls right across your 9th and 3rd Houses- your axis of communication. This is the first time this part of your life has been shaken up by an eclipse since 2002. There will be 7 of these between now and 2021, changing circumstances around you so that you have to change in response. This eclipse will shake up your mental circuitry, your perceptions and your world view. Your current ways of thinking aren’t getting the results you need. Look at where your limiting beliefs are holding you back and update them. The key to collaborating with these changes beyond your control is to consciously expand beyond your comfort zone, meet new people who aren’t strangers to amazement, study, teach, explore.
Finding new purpose and meaning.
Taurus Weekly Forecast: May 31-June 7, 2020
Cast your mind back to summer 2002 and changes you made that altered your trajectory. You’re about to experience the first wild card eclipse in the same part of your chart and life since then. As a Venus ruled Taurean, this Full Moon eclipse activates your 8th/2nd Houses of money and resources. A whole 18 year cycle has ended and a new one is about to begin. Friday’s eclipse is all about stripping right back to essentials, identifying what and who you really value and making these the priorities you live your life around day to day. As circumstances shift around you, you’ll be asking yourself questions such as: what does money mean to me? have I been undervaluing what I have to offer? am I in debt and what am I going to do about it?
The next 18 months will repeat these themes over and over so that you rebuild your personal security from the ground up.
Gemini Weekly Forecast: May 31-June 7, 2020
Life is changing quickly all around you starting this week at the first eclipse across Gemini/Sagittarius since 2002.Think back to that time to follow the thread. Gemini is right in the heart of the planetary action with Venus conjunct the eclipse Sun. With your 1st/7th Houses eclipsed, you’re ready to express a new way of being in the world and experience the evolutionary impact of others in your life. Events will shift around you, raising issues about dependence or independence, going your own way or developing more permanent relationships. How you see yourself versus how others see you is at the heart of it and if there’s a gap, reconcile the differences. Ask yourself: are my relationships mirroring who I am today or who I used to be?
Negotiating new interpersonal “contracts”.
Cancer Weekly Forecast: May 31-June 7, 2020
On Friday, the first eclipse across your 12th/6th Houses since the summer of 2002 nudges you to grow beyond the familiar four walls of your physical habits and routines and make some self-supporting choices. In other words, put your well being right at the top of your agenda. Circumstances beyond your control will nudge you to conquer self-defeating behaviours. Eclipses can change things in a blink of an eye so if you haven’t had a health check for a while, schedule one in. This is the axis of retreat, so if you’re in overwhelm at work or at home, rest up and put your own highest interests first. It’s definitely a time for fixing what can be fixed, then surrendering what you can’t control. Mindful activities such as journaling, yoga or meditation will balance your body/mind/spirit so you can see the wood for the trees.
It is enough simply to be.
Leo Weekly Forecast: May 31-June 7, 2020
Just like Aries, this is going to a super intense week when as a Fire sign, you are going to feel as if you’re combusting. The first wild card eclipse across Sagittarius/Gemini since summer 2002 is shaking up your axis of authenticity and creativity, ending one 18 year cycle and catalysing another. The 5/11th Houses are all about having the courage of your convictions, of expressing your true self and finding your true voice. No more hiding behind a mask or persona or making nice just to fit in. There will be 7 eclipses in total between now and the end of 2021, shaking up this part of your life by changing circumstances around you so that you have to change alongside them. You might start envisioning a new project or a different form of business or service. Make sure you enrol your supporters and collaborators and get them onside-that way you can develop your very own ideas factory.
Make fun, pleasure and fulfilment your keystones.
Virgo Weekly Forecast: May 31-June 7, 2020
Put June 1-8 in your calendar-when the seismic window from Friday’s eclipse will send ripples of endings and new beginnings across your life. Eclipses are cosmic wild cards, shifting circumstances outside your control so that you have to grow and change alongside them. As a solar Virgo, this is the first shake up of your 10/4th Houses since 2002-3, so think back to those times for possible clues. Starting at this eclipse and through 6 more between now and the end of 2021, you will start aligning your personal mission with who you are in the world. You may be recognised on a whole new professional level. You may start to create a legacy, something you can be really proud of. Your driver will be how to get paid for being yourself.
Losing the separation between yourself and your work in the world.
Libra Weekly Forecast: May 31-June 7, 2020
With your personal planet Venus conjunct the Sun at Friday’s eclipse, change is definitely on the cards. This is the first wild card eclipse across your 3rd/9th House since 2002-3, closing down an entire 18 year cycle. This is your axis of communication and connection so expect changes in events or circumstances beyond your control to affect these areas. People might leave, others arrive. Doors might open when there were none before. What’s at stake here is your ability to move with the times, to expand your world view, your people networks and your communication style. As the pandemic restrictions change the world of work, this is the perfect time to develop more effective ways of reaching out to colleagues, clients, your market and your various tribes. Take a course in new ways of thinking and creating rapport with everyone you come across. This will need to become one of your new superpowers.
Scorpio Weekly Forecast: May 31-June 7, 2020
For you as a solar Scorpio, on Friday June 5th, the first wild card eclipse across Sagittarius/Gemini since 2002-3 marks the end of an 18 year financial cycle and the start of a new one. The Full Moon in Sagittarius lights up your 2nd House of earned income and personal resources, putting your financial security under the planetary spotlight. It is linked to shared resources so a close partner may make a move that surprises you. All eclipses operate under the radar, changing people and events around you so that you have no choice but to grow and evolve. This is a big nudge for you to think about how you attract and earn money; what money means to you; whether you hold on to it or let it slip through your fingers; whether you are optimising your earning ability and income streams.
The pandemic is bringing opportunities to develop more creative ways of working-think out of the box.
Sagittarius Weekly Forecast: May 31-June 7, 2020
A heads up! For you as a solar Sagittarian, the days between June 1-8 are sure to accelerate the pace of life and bring some unforeseen changes. Friday’s lunar eclipse is the first across your sign and Gemini since 2002-3, so try to remember what changed for you back then. This is the axis of identity and partnership so it will bring up issues of relationship dynamics such as control or cooperation, co-dependence or independence. If you are in a partnership, you’re likely to be the one who wants more freedom, who needs to disrupt the comfort zone and inject some excitement and passion. The unspoken unconscious contract you set up when you first met needs updating. Keep in mind that everyone will be more tired and wired around eclipse time, avoid Sagittarian hoof in mouth syndrome and tread carefully. Leave any big decisions until the eclipse dust has settled.
Don’t throw the baby out with the bath water.
Capricorn Weekly Forecast: May 31-June 7, 2020
As a Capricorn, this intense period between June 1-8th may seem a contradiction in terms. Yes, it’s eclipse season again which means events shifting and circumstances changing beyond your control, often almost overnight. Yet, this lunar eclipse is activating your 12th/6th Houses, the axis of retreat. This a clear message that you need to step back from the fray and look more deeply at how your life is unfolding. It’s so easy to get so caught up in doing that you forget what it’s all for. Slow down and re-group. Is your ladder up against the wrong tree? Is duty, work, service or routine draining your spirit? Are those important goals still a true reflection of who you are or of who you used to be? The last few years have been incredibly challenging for most Capricornians, so put your wellbeing-mind/body/spirt-at the top of your agenda.
Less doing, more being.
Aquarius Weekly Forecast: May 31-June 7, 2020
The eclipses are here! And for you as a solar Aquarian, they mark an end to one 18 year cycle and the start of another which promises to be much more appealing. Think back to 2002-3, the last time an eclipse activated your 11th/5Th Houses of creative births and hopes for the future. What did you initiate, launch or change back then? This time round, you have both your rulers Saturn and Uranus in your corner, waking you up to smell both the coffee and the roses. Eclipses take you from one stage of life to another, often in the blink of an eye. So, forget about resisting the changes heading your way and grab the opportunity to make your life and your world a bigger, freer and more interesting place.
Bring on those radical acts of self-love and self-expression.
Pisces Weekly Forecast: May 31-June 7, 2020
On Friday June 5th, the first eclipse since 2002-3 across Sagittarius/Gemini activates key angles of your chart ,marking a turning point in your autobiography. The Full Moon is going to set in motion changes beyond your control in both your career and your home- your work/life axis. And there will be 6 more eclipses in the same place between now and the end of 2021. This time around, you are hosting both Mars and Pisces in your own sign so whatever plays out in the days and weeks to come, you can rely on your instincts and determination to steer you through it. What’s at issue is how you work, where you work, who you live with and how your home base either supports you or sabotages you. With the eclipse Moon right at the pinnacle of your chart, recognition for work completed is highly likely, so use this to your advantage as leverage for the changes you’d really like to make.
The coronavirus pandemic has brought chaos to lives and economies around the world. But efforts to curb the spread of the virus might mean that the planet itself is moving a little less. Researchers who study Earth’s movement are reporting a drop in seismic noise — the hum of vibrations in the planet’s crust — that could be the result of transport networks and other human activities being shut down. They say this could allow detectors to spot smaller earthquakes and boost efforts to monitor volcanic activity and other seismic events.
A noise reduction of this magnitude is usually only experienced briefly around Christmas, says Thomas Lecocq, a seismologist the Royal Observatory of Belgium in Brussels, where the drop has been observed.
Just as natural events such as earthquakes cause Earth’s crust to move, so do vibrations caused by moving vehicles and industrial machinery. And although the effects from individual sources might be small, together they produce background noise, which reduces seismologists’ ability to detect other signals occurring at the same frequency.
Data from a seismometer at the observatory show that measures to curb the spread of COVID-19 in Brussels caused human-induced seismic noise to fall by about one-third, says Lecocq. The measures included closing schools, restaurants and other public venues from 14 March, and banning all non-essential travel from 18 March (see ‘Seismic noise’).
The current drop has boosted the sensitivity of the observatory’s equipment, improving its ability to detect waves in the same high frequency range as the noise. The facility’s surface seismometer is now almost as sensitive to small quakes and quarry blasts as a counterpart detector buried in a 100-metre borehole, he adds. “This is really getting quiet now in Belgium.”
If lockdowns continue in the coming months, city-based detectors around the world might be better than usual at detecting the locations of earthquake aftershocks, says Andy Frassetto, a seismologist at the Incorporated Research Institutions for Seismology in Washington DC. “You’ll get a signal with less noise on top, allowing you to squeeze a little more information out of those events,” he says.
The fall in noise could also benefit seismologists who use naturally occurring background vibrations, such as those from crashing ocean waves, to probe Earth’s crust. Because volcanic activity and changing water tables affect how fast these natural waves travel, scientists can study these events by monitoring how long it takes a wave to reach a given detector. A fall in human-induced noise could boost the sensitivity of detectors to natural waves at similar frequencies, says Lecocq, whose team plans to begin testing this. “There’s a big chance indeed it could lead to better measurements,” he says.
Belgian seismologists are not the only ones to notice the effects of lockdown. Celeste Labedz, a graduate student in geophysics at the California Institute of Technology in Pasadena, tweeted that a similar fall in noise had been picked up by a station in Los Angeles. “The drop is seriously wild,” she said.
However, not all seismic monitoring stations will see an effect as pronounced as the one observed in Brussels, says Emily Wolin, a geologist at the US Geological Survey in Albuquerque, New Mexico. Many stations are purposefully located in remote areas or deep boreholes to avoid human noise. These should see a smaller decrease, or no change at all, in the level of high-frequency noise they record, she says.
Soon after Salt Lake City stopped shaking March 18 from its strongest earthquake on record, Amir Allam, a University of Utah seismologist, knew he had to get busy if he hoped to closely study the hundreds of aftershocks he knew would follow the 7:09 a.m. jolt.
The fault that is believed to have moved along the eastern base of the Oquirrh Mountains is virtually unknown, and here was a chance, dropping out of the blue, to image it.
But Allam had a problem.
All 210 of the U.’s portable seismographs, loaf-sized instruments known as nodal geophones, were currently deployed along California’s San Andreas fault and elsewhere, and, therefore, were unavailable for what he needed to do in his own backyard. The Salt Lake Valley hadn’t had a sizable shake since 1962 and last week’s 5.7 magnitude earthquake offered a rare opportunity to better map the network of fractures under the valley.
(Francisco Kjolseth | The Salt Lake Tribune) University of Utah seismologist Amir Allam unloads 50-pound bags filled with p…
Allam and his U. colleagues quickly mustered up dozens of geophones from other institutions and began burying them near the epicenter of the initial quake, likely on a fault that has remained a mystery to Utah seismologists.
They hope to characterize it and determine how it is interconnected with the Wasatch fault running along the base of the foothills on Salt Lake City’s east side and its lattice of associated faults, or “strands.”
‘Jury is still out’
“We started immediately the morning of the [initial] earthquake, and we have been installing them ever since,” Allam said Tuesday as he unloaded shovels and 43 geophones from his truck. “These are the last bunch.”
He already had deployed 139 geophones, each equipped with 35 days of battery life, around the Salt Lake Valley, each measuring ground movements — vertical, north-south and east-west — from hundreds of aftershocks. These recordings will help scientists with the U., as well as the Utah and U.S. geological surveys, to characterize this intriguing fault.
The Wasatch fault system’s network of cracks in the earth stretches 230 miles from Malad, Idaho south to Fayette, Utah through Utah’s major metropolitan area, where at least 80% of the population resides. A magnitude 6 quake on the main fault could cause severe damage, depending on where it strikes. A 2016 report forecast a 57% chance of such a quake or stronger within the next 50 years. Scientists do not believe last week’s temblor will reduce the chance of a major quake on the Wasatch fault down the road.
“We want to map out the basin depth all over the valley. We actually don’t know it [the fault network] that well,” Allam said. “… We want to capture as many tiny aftershocks as we can, so we have a really dense deployment around the epicenter of the 5.7 quake. We want to get that fault structure. We want to know exactly how the Wasatch and its subsidiary faults are changing their patterns in the subsurface.”
The fault that likely moved dips to the west and is not expressed on the surface, according to Kris Pankow of the U. Seismograph Stations. It could be the same one that shook Magna in 1962 with a magnitude 5.2 quake that touched off a swarm of lesser aftershocks, but it can’t be known for sure because the instrumentation was not in place to precisely locate that quake.
“The jury is still out on the specific fault that moved and produced [the March 18] earthquake,” said Ryan Gold, a research geologist with the U.S. Geological Survey. “The specific strand, that’s what we are trying to sort out. Additional instrumentation is being installed to monitor ongoing seismicity.”
‘Aftershocks are going to diminish’
In the week since the main quake, the ground under Magna has kept shaking.
As of Tuesday at 4 p.m., 456 aftershocks had been recorded, according to Gold, coming at an average rate of one every 20 minutes. At least 29 were magnitude 3 and a handful exceeded magnitude 4. The fault released a magnitude 3.1 temblor Tuesday at 5:32 a.m., followed by many stronger than magnitude 2. Most were located very close to the original epicenter a few miles north northeast of Magna and just six miles beneath the surface.
“The number and size of aftershocks are going to diminish with time but within these sequences. It’s the fault adjusting to the changes in stress. They are kind of chattering,” said Pankow, who is also closely monitoring aftershocks with larger seismographs placed in a few strategic locations. “With time, that stress is going to dissipate.”
The larger instruments are connected to broadband, providing real time data on the aftershocks. Meanwhile, satellite imagery shows the ground moved several centimeters at the surface as a result of the main quake, according to Gold.
The aftershocks don’t occur in steady intervals but in clusters, according to a graphic representation posted by Seismograph Stations. In the first three days after the mainshock, dozens of aftershocks flared. They grew weaker and less frequent until Sunday night, when a magnitude 4 struck, followed quickly by numerous aftershocks.
“That magnitude 4 was its own stress release; it has its own set of aftershocks to go with it,” Pankow said. “We might have some more magnitude 4s before this is all done.”
Seismometers, types of seismograph that measure surface ground movement, are installed in at least three major historic structures in downtown Salt Lake City: the Utah Capitol, City Hall and West High School. These instruments record direction, intensity and duration of earthquakes. The data generated by these instruments helps engineers understand the seismic forces buildings on the Wasatch fault system could be subject to, according to Pankow.
They hoisted 50-pound satchels over their shoulders, each holding six geophones, and trekked a half-mile up the Bonneville Shoreline Trail to a spot where Allam had identified a 500-meter transect along a ravine that was just starting to green up with the coming of spring. Here the team was to plant the geophones along a preselected line spanning a known strand of the Wasatch fault in the undulating terrain overlooking the city.
As a cold rain began to fall, the crews dug 8-inch holes in 13-meter intervals along a downsloping ridgeline on a roughly north-south axis. The geophones were placed in the holes, oriented directly north, and covered with dirt.
In a month, Allam and his associates will return to recover 182 geophones around the valley. The harvest is hoped to yield a bounty of data that paints a valuable picture of what lurks beneath Utah’s most populated region.
A magnitude 6.4 earthquake shook southwestern Puerto Rico this morning (Jan. 7), according to the U. S. Geological Survey (USGS); this is the largest yet in a series of quakes that have hit the region.
At least one person died as walls collapsed around the area, and eight more people were injured, according to NPR. Electricity went out across Puerto Rico as automated systems shut down the island’s power plants, recalling power outages that lasted 11 months after Hurricane Maria, which caused the worst blackout in US history. The North American and Caribbean tectonic plates meet in this area, but the quake doesn’t appear to be the result of those plates grinding together, according to USGS. Instead, a release of energy and stress inside the Caribbean plate seems to have caused the shaking.
A day earlier, a smaller, 5.8 magnitude quake in the same area destroyed a natural rock archway along the coast known as the Punta Ventana, NPR reported. Since a 4.7 magnitude earthquake struck the area on Dec. 28, 2019, more than 400 quakes of at least magnitude 2 have hit Puerto Rico’s southwest region. Eleven have been magnitude 4 or greater, according to USGS.
(The numbers used to measure quakes are nonlinear. A magnitude 3 quake is 10 times as powerful as a magnitude 2 quake, and a magnitude 4 quake is 10 times as powerful as a magnitude 3 quake and so on.)
Puerto Rico’s governor, Wanda Vázquez, suspended work for the day for public sector workers who aren’t first responders.
March 24, 2018 Update: “Something’s Not Right in Southern Oregon”
— “I have 2 large bird feeders and 2 hummingbird feeders that I’ve been refilling all winter — until about a week ago! Nothing — no birds! We also have a large population of geese that are always in our park, but nothing for over a week?”
– GG, Worried Resident, Grants Pass Oregon valley
— “Are we about to experience a severe natural disaster?”
– Resident, Rogue Valley, Oregon on March 19, 2018
UPDATE – March 24, 2018 Rogue Valley, Oregon – Since my March 19th Earthfiles report and March 21st Earthfiles YouTube Update about the puzzling and disturbing lack of birds in Rogue Valley, Oregon, near Medford, and possible link to impending earthquake in the Cascadia Subduction Zone there, I have received the following comments from viewers and listeners.
To: Linda Moulton Howe <firstname.lastname@example.org>
Re: Birds Also Missing in Grants Pass Oregon valley
Date: March 23, 2018
I live in the Grants Pass Oregon valley. I have only lived here for a few years, but one of my joys of the valley is feeding my birds! Swallows, hummingbirds, robins throughout the season and especially the winter. I have 2 large bird feeders and 2 hummingbird feeders that I’ve been refilling all winter — until about a week ago! Nothing — no birds! We also have a large population of geese that are always in our park, but nothing for over a week?
We also own a home in the Smith River Oregon area. We have also noticed our large robin population has vacated?
We have lived in that area for over 40 years. The robins are always, always early morning feeders for us. Have not seen ANY in over a week?
We will be even more aware now to see what our large elk population and wildlife are doing….
To read more, go to link: from: https://www.earthfiles.com/2018/03/24/march-24-2018-update-somethings-not-right-in-southern-oregon/
A team of researchers from the University of Hawai’i at Mãnoa, University of Washington and Scripps Institution of Oceanography (SIO) analyzed the motion of Earth’s crust from the data collected by an array of GPS instruments placed near the San Andreas Fault System in Southern California. Their results revealed almost 201 km (125 miles) wide lobes of uplift and subsidence straddling the fault system. The motion has not been recorded so far, although it was predicted by theoretical models.
The GPS instruments record a vertical and horizontal motion of our planet’s surface. The tectonic motion of the crust, groundwater pumping, local surface geology, and precipitation amount all affect the vertical motion, and it was challenging to distinguish the broad, regional tectonic motion from the local motion.
The scientists have used comprehensive statistical methods to analyze the data recorded by the EarthScope Plate Boundary Observatory’s GPS network, and extract a large-scale pattern of smoothly varying vertical motions of the local crust.
San Andreas Fault in the Coachella Valley; from Keys View, February 12, 2014. Image credit: NPS/Robb Hannawacker/Joshua Tree National Park via Flickr-CC
“While the San Andreas GPS data has been publicly available for more than a decade, the vertical component of the measurements had largely been ignored in tectonic investigations because of difficulties in interpreting the noisy data. Using this technique, we were able to break down the noisy signals to isolate a simple vertical motion pattern that curiously straddled the San Andreas fault,” said Samuel Howell, a doctoral candidate at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST) and lead author of the study.
The results responded to those previously predicted by an earthquake cycle model, led by co-authors Bridget Smith-Konter, associate professor at SOEST, and David Sandwell, a professor at SIO.
Uplift (red) and subsidence (blue) based on GPS data (top) confirm predicted motion (bottom). Image credit: University of Hawai’i
“We were surprised and thrilled when this statistical method produced a coherent velocity field similar to the one predicted by our physical earthquake cycle models. The powerful combination of a priori model predictions and a unique analysis of vertical GPS data led us to confirm that the buildup of century-long earthquake cycle forces within the crust are a dominant source of the observed vertical motion signal,” said Smith-Konter.
New research suggests the scientists can use GPS vertical motion measurements to improve the understanding of the structure and behavior of faults, even when no major ruptures occurred for decades or, even, centuries. Results are expected to contribute to constraining the seismic hazard estimates from the San Andreas Fault System, and could enable mapping of the large-scale motion resulting from the next significant rupture of the fault, in more detail.
“The vertical fingerprint of earthquake cycle loading in southern California” – Samuel Howell, Bridget Smith-Konter, Neil Frazer, Xiaopeng Tong & David Sandwell – Nature Geoscience (2015) – doi:10.1038/ngeo2741
Featured image: San Andreas fault in the Coachella Valley; from Keys View, February 12, 2014. Image credit: NPS/Robb Hannawacker/Joshua Tree National Park via Flickr-CC
(To check out the image, go to: http://www.livescience.com/54212-oklahoma-is-now-earthquake-hotspot.html)
Man-Made Earthquake Hotspot Revealed: Oklahoma
by Laura Geggel, Staff Writer
The chances of a damaging earthquake occurring in parts of Oklahoma and some neighboring states are just as likely as they are in temblor-heavy California, according to a report by the U.S. Geological Survey (USGS).
The culprit? Man-made activities related to oil and gas production are creating the shaky conditions in a region of the central and eastern U.S., the USGS seismologists say.
USGS scientists just released their first map that includes earthquake risks from both natural and human-induced causes for the coming year. Until now, the government agency included only temblor risks linked to natural causes.
The report, which is part of a 50-year forecast examining earthquake hazards, reveals that about 7 million people live and work in areas at risk of human-induced seismicity. Areas in the central and eastern U.S. (CEUS) are at risk of experiencing a quake of the same magnitude as those that occur naturally in California, the USGS said. [Image Gallery: This Millennium’s Destructive Earthquakes]
“By including human-induced events, our assessment of earthquake hazards has significantly increased in parts of the U.S.,” Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project, said in a statement. “This research also shows that much more of the nation faces a significant chance of having damaging earthquakes over the next year, whether natural or human-induced.”
The CEUS’ induced earthquakes are often the product of wastewater disposal, the USGS said. This wastewater comes from oil and gas production, when it is pumped into underground wells deep in the Earth. This is different from hydraulic fracturing, also known as fracking, in which water, sand and chemicals get pumped into the Earth to break up rock and extract oil and gas. The actual fracking is probably a more infrequent cause of felt earthquakes, the USGS said. (Wastewater from fracking is generally pumped back into wastewater injection wells.)
Still, wastewater injection practices have put six states on the earthquake map. Oklahoma has the highest risk, followed by Kansas, Texas, Colorado, New Mexico and Arkansas, the USGS reported. Oklahoma and Texas have the largest populations living near induced-earthquake hotspots.
“In the past five years, the USGS has documented high shaking and damage in areas of these six states, mostly from induced earthquakes,” Petersen said. “Furthermore, the USGS Did You Feel It? website has archived tens of thousands of reports from the public who experienced shaking in those states, including about 1,500 reports of strong shaking or damage.”
For instance, from 1973 to 2008, an average of 24 earthquakes with a magnitude of 3.0 or higher shook the central United States in each of those years. But, from 2009 to 2015, that number increased to an average of 318 earthquakes of that magnitude per year. 2015 saw the greatest number, with 1,010 earthquakes of a magnitude 3.0 or greater. [Video: Watch 2,500+ Earthquakes in Oklahoma Linked to Humans]
And through mid-March of this year, 226 earthquakes of a magnitude 3.0 or higher have already hit the central United States, the USGS said. The largest earthquake to occur near a wastewater injection site was a magnitude-5.6 temblor near Prague, Oklahoma, in 2011.
Overall, USGS researchers found 21 areas with increased rates of human-induced seismicity. Some areas — such as regions within Alabama and Ohio — experienced human-induced earthquakes in the past, but have relatively little risk in the coming year because the activities that caused these quakes have decreased.
But other areas of Alabama and some parts of Mississippi have shown an increase in these activities. But researchers are still determining whether earthquakes in these areas happened naturally or were human-induced, the USGS said.
The scientists found the greatest risk of a human-induced earthquake in north central Oklahoma and the southernmost part of Kansas. They calculated that there is a 10 to 12 percent risk that an earthquake with strong shaking will occur in those areas this year. Such an earthquake, they estimated, would register a 6 or greater on the Modified Mercalli Intensity scale, meaning it would easily be felt but would likely cause just slight damage. This translates into about a 5.0 on the Richter scale.
Though scientists disagree about whether wastewater injection leads to larger or smaller earthquakes compared with natural ones, in the CEUS region, when a large temblor does strike, thousands of faults could rupture, according to the USGS. What’s more, human-induced quakes tend to come in swarms of smaller events at shallower depths, whereas shaking is more likely to be felt and cause damage.
The new earthquake report will help architects determine how to safely design buildings within areas of high risk. People who live in earthquake territory can read about safety measures at FEMA’s Ready Campaign.