Earth’s Magnetic Pole Shifting at Unexpected Speed

Rapid shifts in the Earth’s north magnetic pole are forcing researchers to make an unprecedented early update to a model that helps navigation by ships, planes and submarines in the Arctic, scientists said.

Compass needles point towards the north magnetic pole, a point which has crept unpredictably from the coast of northern Canada a century ago to the middle of the Arctic Ocean, moving towards Russia.

Arnaud Chulliat is a scientist at the University of Colorado in Boulder, Colorado. He is also the lead researcher for the newly updated World Magnetic Model. Chulliat told the Associated Press the continuous movement of magnetic north is a problem for compasses in smartphones and other electronic devices.

“It is moving at about 50 km (30 miles) a year. It did not move much between 1900 and 1980 but it is really accelerated in the past 40 years,” reports Ciaran Beggan, of the British Geological Survey in Edinburgh.

A five-year update of a World Magnetic Model was due in 2020 but the U.S. military requested an unprecedented early review, he said. The BGS runs the model with the U.S. National Oceanic and Atmospheric Administration.

Beggan said the moving pole affected navigation, mainly in the Arctic Ocean north of Canada. NATO and the U.S. and British militaries are among those using the magnetic model, as well as civilian navigation.

The wandering pole is driven by unpredictable changes in liquid iron deep inside the Earth. An update will be released on January 30, the journal Nature said, delayed from January 15 because of the U.S. government shutdown.

“The fact that the pole is going fast makes this region more prone to large errors,” Arnaud Chulliat, a geomagnetist at the University of Colorado Boulder and NOAA’s National Centers for Environmental Information, told Nature.

Beggan said the recent shifts in the north magnetic pole would be unnoticed by most people outside the Arctic, for instance using smartphones in New York, Beijing or London.

Many smartphones have inbuilt compasses to help to orientate maps or games such as Pokemon Go. In most places, however, the compass would be pointing only fractionally wrong, within errors allowed in the five-year models, Beggan said.

Innovative Method Enables New View Into Earth’s Interior

An innovative X-ray method enables new high-pressure investigations of samples under deep mantle conditions. The technique, which was developed by a team led by Georg Spiekermann from DESY, the German Research Centre for Geosciences GFZ and the University of Potsdam, extends the range of instruments available to high-pressure researchers. Successful tests of the new method at DESY’s X-ray light source PETRA III support the idea that heavy elements have to accumulate in magmas so that they could be stable at depths of Earth’s lower mantle. The scientists present their work in the journal Physical Review X.

The so-called standard conditions of chemistry, i.e. a temperature of 25 degrees Celsius and a pressure of 1013 millibar, are actually rare in nature. Most of the matter in the universe exists under completely different conditions. In Earth’s interior, for example, pressure and temperature rise rapidly to many times the standard conditions. “However, even with the most elaborate deep drilling, only the uppermost part of the Earth’s crust is accessible,” Spiekermann emphasises. Researchers therefore simulate the conditions of Earth’s interior in the laboratory in order to investigate the behaviour of matter under these conditions.

Such experiments often involve determining the inner structure of the samples, which in many materials changes with increasing pressure. This inner structure can be explored with X-rays that are energetic enough to penetrate the sample and short enough in wavelength to resolve the tiny details of atomic distances. For this purpose, usually two X-ray based methods exist in high-pressure research: absorption and diffraction of X-rays through the sample.

Based on X-ray emission, Spiekermann and his team have now developed a third method that can be used to determine both the bonding distances in compressed amorphous (disordered) matter and the so-called coordination number, which indicates how many direct neighbours an atom has. These parameters can be read from the energy and intensity of the radiation of a certain emission line of the sample, called Kβ” (“K-beta-doubleprime”). The Kβ” radiation is generated when the sample is excited with X-rays. The energy of the emission line depends on the coordination number, the intensity on the bonding distance.

Experiments at the experimental station P01 at DESY’s X-ray source PETRA III have confirmed the new method. “We have shown this, using the spectrum of germanium in compressed amorphous germanium dioxide, but this procedure can also be applied to other chemical systems,” says Spiekermann.

The method will provide scientists with an additional technique for investigating the structure of high-pressure samples. “The insight provided by a new measuring method is particularly welcome when different methods have so far produced significantly different results so far, as in the case of compressed amorphous germanium dioxide,” explains DESY researcher Hans-Christian Wille, head of the measuring station P01 at which the experiments took place.

For their experiments, the researchers exposed samples of germanium dioxide (GeO2) to a pressure of up to 100 gigapascals, about one million times as much as the atmospheric pressure at sea level. This pressure corresponds to a depth of 2200 kilometres in the lower mantle of Earth. The measurements show that the coordination number of germanium dioxide does not rise higher than six even under this extreme pressure. This means that even in the high-pressure phase, the germanium atoms each still have six neighbouring atoms as already at 15 gigapascals.

This result is of great interest for the exploration of Earth’s interior, because germanium dioxide has the same structure and behaves like silicon dioxide (SiO2), which is the main component of natural magmas in general. Since melts such as magma generally have a lower density than the solid form of the same material, it has long been a mystery why magmas at great depth do not rise towards the surface over geological periods.

“There are two possible explanations for this, one chemical, the other structural,” Spiekermann explains. “Either heavy elements such as iron accumulate in the melt, or there is a special compacting mechanism in melts that makes melts denser than crystalline forms of the same composition.” The latter would be noticeable, among other things, by an increase in the coordination number under high pressure.

“Our investigations show that up to 100 gigapascals the coordination number in non-crystalline germanium dioxide is not higher than in the corresponding crystalline form,” reports the researcher. Applied to silicon dioxide, this means that magma with a higher density can only be produced by enriching relatively heavy elements such as iron. The composition and structure of the lower mantle have far-reaching consequences for the global transport of heat and the propagation of Earth’s magnetic field.

New Research Sheds Light on Lost Continent Zealandia

New data collected by University of Wyoming researchers and others point to a newly defined mantle domain in a remote part of the Southern Ocean.

UW Department of Geology and Geophysics Professor Ken Sims and recent Ph.D. graduate Sean Scott are co-authors of an article, “An isotopically distinct Zealandia-Antarctic mantle domain in the Southern Ocean,” published by the scientific journal Nature Geoscience in January.

Zealandia is an almost entirely submerged mass of continental crust that sank after breaking away from Australia 60–85 million years ago, having separated from Antarctica between 85 and 130 million years ago. It has been described as a lost continental, a microcontinent, and submerged continent. The name and concept for Zealandia was proposed by Bruce Luyendyk in 1995.

The land mass may have been completely submerged about 23 million years ago, and most of it (93%) remains submerged beneath the Pacific Ocean. With a total area of approximately 4,920,000 km2 (1,900,000 sq mi), it is the world’s largest current microcontinent, more than twice the size of the next-largest microcontinent Mauritia, and more than half the size of the Australian continent.

As such, and due to other geological considerations, such as crustal thickness and density, it is arguably a continent in its own right. This was the argument which made news in 2017, when geologists from New Zealand, New Caledonia, and Australia concluded that Zealandia fulfills all the requirements to be considered a continent, rather than a microcontinent or continental fragment.

The Magnetic North Pole Is On The Move

North isn’t quite where it used to be.

Earth’s north magnetic pole has been drifting so fast in the last few decades that scientists say that past estimates are no longer accurate enough for precise navigation. On Monday, they released an update of where magnetic north really was, nearly a year ahead of schedule.

The magnetic north pole is wandering about 34 miles (55 kilometers) a year. It crossed the international date line in 2017, and is leaving the Canadian Arctic on its way to Siberia.

The constant shift is a problem for compasses in smartphones and some consumer electronics. Airplanes and boats also rely on magnetic north, usually as backup navigation, said University of Colorado geophysicist Arnaud Chulliat, lead author of the newly issued World Magnetic Model. GPS isn’t affected because it’s satellite-based.

The military depends on where magnetic north is for navigation and parachute drops, while NASA, the Federal Aviation Administration and U.S. Forest Service also use it. Airport runway names are based on their direction toward magnetic north and their names change when the poles moved. For example, the airport in Fairbanks, Alaska, renamed a runway 1L-19R to 2L-20R in 2009.

The U.S. National Oceanic and Atmospheric Administration and United Kingdom tend to update the location of the magnetic north pole every five years in December, but this update came early because of the pole’s faster movement.

The movement of the magnetic north pole “is pretty fast,” Chulliat said.

Since 1831 when it was first measured in the Canadian Arctic it has moved about 1,400 miles (2300 kilometers) toward Siberia. Its speed jumped from about 9 miles per year (15 km per year) to 34 miles per year (55 km per year) since 2000.

The reason is turbulence in Earth’s liquid outer core. There is a hot liquid ocean of iron and nickel in the planet’s core where the motion generates a magnetic field, said University of Maryland geophysicist Daniel Lathrop, who wasn’t part of the team monitoring the magnetic north pole.

“It has changes akin to weather,” Lathrop said. “We might just call it magnetic weather.”

The magnetic south pole is moving far slower than the north.

In general Earth’s magnetic field is getting weaker, leading scientists to say that it will eventually flip, where north and south pole changes polarity, like a bar magnet flipping over. It has happened numerous times in Earth’s past, but not in the last 780,000 years.

“It’s not a question of if it’s going to reverse, the question is when it’s going to reverse,” Lathrop said.

When it reverses, it won’t be like a coin flip, but take 1,000 or more years, experts said.

Lathrop sees a flip coming sooner rather than later because of the weakened magnetic field and an area over the South Atlantic has already reversed beneath Earth’s surface.

That could bother some birds that use magnetic fields to navigate. And an overall weakening of the magnetic field isn’t good for people and especially satellites and astronauts. The magnetic field shields Earth from some dangerous radiation, Lathrop said.

MERMAIDs Reveal Secrets from Below the Ocean Floor

Seismologists use waves generated by earthquakes to scan the interior of our planet, much like doctors image their patients using medical tomography. Earth imaging has helped us track down the deep origins of volcanic islands such as Hawaii, and identify the source zones of deep earthquakes.

“Imagine a radiologist forced to work with a CAT scanner that is missing two-thirds of its necessary sensors,” said Frederik Simons, a professor of geosciences at Princeton. “Two-thirds is the fraction of the Earth that is covered by oceans and therefore lacking seismic recording stations. Such is the situation faced by seismologists attempting to sharpen their images of the inside of our planet.”

Some 15 years ago, when he was a postdoctoral researcher, Simons partnered with Guust Nolet, now the George J. Magee Professor of Geoscience and Geological Engineering, Emeritus, and they resolved to remediate this situation by building an undersea robot equipped with a hydrophone—an underwater microphone that can pick up the sounds of distant earthquakes whose waves deliver acoustic energy into the oceans through the ocean floor.

This week, Nolet, Simons and an international team of researchers published the first scientific results from the revolutionary seismic floats, dubbed MERMAIDs—Mobile Earthquake Recording in Marine Areas by Independent Divers.

The researchers, from institutions in the United States, France, Ecuador and China, found that the volcanoes on Galápagos are fed by a source 1,200 miles (1,900 km) deep, via a narrow conduit that is bringing hot rock to the surface. Such “mantle plumes” were first proposed in 1971 by one of the fathers of plate tectonics, Princeton geophysicist W. Jason Morgan, but they have resisted attempts at detailed seismic imaging because they are found in the oceans, rarely near any seismic stations.

MERMAIDs drift passively, normally at a depth of 1,500 meters—about a mile below the sea surface—moving 2-3 miles per day. When one detects a possible incoming earthquake, it rises to the surface, usually within 95 minutes, to determine its position with GPS and transmit the seismic data.

By letting their nine robots float freely for two years, the scientists created an artificial network of oceanic seismometers that could fill in one of the blank areas on the global geologic map, where otherwise no seismic information is available.

The unexpectedly high temperature that their model shows in the Galápagos mantle plume “hints at the important role that plumes play in the mechanism that allows the Earth to keep itself warm,” said Nolet.

“Since the 19th century, when Lord Kelvin predicted that Earth should cool to be a dead planet within a hundred million years, geophysicists have struggled with the mystery that the Earth has kept a fairly constant temperature over more than 4.5 billion years,” Nolet explained. “It could have done so only if some of the original heat from its accretion, and that created since by radioactive minerals, could stay locked inside the lower mantle. But most models of the Earth predict that the mantle should be convecting vigorously and releasing this heat much more quickly. These results of the Galápagos experiment point to an alternative explanation: the lower mantle may well resist convection, and instead only bring heat to the surface in the form of mantle plumes such as the ones creating Galápagos and Hawaii.”

To further answer questions on the heat budget of the Earth and the role that mantle plumes play in it, Simons and Nolet have teamed up with seismologists from the Southern University of Science and Technology (SUSTech) in Shenzhen, China, and from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Together, and with vessels provided by the French research fleet, they are in the process of launching some 50 MERMAIDs in the South Pacific to study the mantle plume region under the island of Tahiti.

“Stay tuned! There are many more discoveries to come,” said professor Yongshun (John) Chen, a 1989 Princeton graduate alumnus who is head of the Department of Ocean Science and Engineering at SUSTech, which is leading the next phase of what they and their international team have called EarthScope-Oceans.

Earthquake with Magnitude 7.5 in Indonesia – an Unusual and Steady Speed

An international team of researchers from the French National Research Institute for Sustainable Development (IRD-France), Université Côte d”Azur, University of California Los Angeles and California Institute of Technology has determined the propagation speed of the 7.5 magnitude earthquake which occurred in Indonesia in September 2018: 4.1 km/s along 150 km. The results, which also shed light on the earthquake rupture path, are published on February 4th in Nature Geoscience.

Earthquakes happen when rocks on either side of a tectonic fault shift suddenly in opposite directions. Two main seismic waves that carry out shaking of a breaking fault are S-waves, which shear rocks and propagate at about 3.5 km/s, and P-waves, which compress rocks and propagate faster, at about 5 km/s.

Geophysical observations show that the speed at which an earthquake ruptures along the fault is either slower than S-waves or almost as fast as P-waves. The latter, so-called supershear earthquakes, occur very rarely and can produce very strong shaking. Only a few have been observed, and they happen on faults that are remarkably straight, geological “superhighways” that present little obstacle to speeding earthquakes.

“Forbidden” speed range

In this study, the international team coordinated by Jean-Paul Ampuero, seismologist at IRD and Université Côte d”Azur, analysed the 7.5 magnitude earthquake that rocked the Sulawesi island in Indonesia on September 28th, devastating Palu’s region.

The impact of the event—more than 2,000 deaths—was aggravated by a devastating sequence of secondary effects, involving soil liquefaction, landslides and a tsunami.

Thanks to a high-resolution analysis of seismological data, researchers identified the propagation speed of the earthquake: 4.1 km/s, an unusual speed, between the speed of S- and P-waves. “This is the first time we observed this speed so steadily,” underlines Jean-Paul Ampuero. “This earthquake ran in the ‘forbidden’ speed range, and can be considered as a supershear event, even if it’s not as fast as previous ones.”

By analyzing optical and radar images recorded by satellites especially re-tasked to observe the earthquake aftermath, the researchers determined the path of the fault rupture. They found that the fault was not straight, but had at least two major bends, and left more than five meters of ground offset across the city of Palu. ” This path has major obstacles, which should have reduced the earthquake’s speed, but it stayed at 4.1 km/s along 150 km,” says Jean-Paul Ampuero.

Toward a better anticipation of future earthquakes

The findings challenge current views of earthquakes in ways that could help researchers and public authorities prepare better for future events. “In classical earthquake models, faults live in idealized intact rocks “, says Ampuero, ” but real faults are wrapped in a layer of rocks that have been fractured and softened by previous earthquakes. Steady rupture at speeds that are unexpected on intact rocks can actually happen on damaged rocks, simply because they have slower seismic wave speeds.”

The Palu earthquake may offer the first clear test of such recent models if followed up by studies of the structure of the fault and its zone of damaged rocks. Because the impact of an earthquake depends strongly on its speed, such studies on other faults around the world could anticipate earthquake effects better.

Future work may also determine if the speed of the Palu earthquake enhanced its cascading effects, by promoting coastal and submarine landslides that in turn contributed to the tsunami.

Researchers Unearth an Ice Age in the African Desert

A field trip to Namibia to study volcanic rocks led to an unexpected discovery by West Virginia University geologists Graham Andrews and Sarah Brown.

While exploring the desert country in southern Africa, they stumbled upon a peculiar land formation—flat desert scattered with hundreds of long, steep hills. They quickly realized the bumpy landscape was shaped by drumlins, a type of hill often found in places once covered in glaciers, an abnormal characteristic for desert landscapes.

“We quickly realized what we were looking at because we both grew up in areas of the world that had been under glaciers, me in Northern Ireland and Sarah in northern Illinois,” said Andrews, an assistant professor of geology. “It’s not like anything we see in West Virginia where we’re used to flat areas and then gorges and steep-sided valleys down into hollows.”

After returning home from the trip, Andrews began researching the origins of the Namibian drumlins, only to learn they had never been studied.

“The last rocks we were shown on the trip are from a time period when southern Africa was covered by ice,” Andrews said. “People obviously knew that part of the world had been covered in ice at one time, but no one had ever mentioned anything about how the drumlins formed or that they were even there at all.”

WVU researcher unearths an ice age in the African desert
Andrew McGrady. Credit: WVU

Andrews teamed up with WVU geology senior Andy McGrady to use morphometrics, or measurements of shapes, to determine if the drumlins showed any patterns that would reflect regular behaviors as the ice carved them.

While normal glaciers have sequential patterns of growing and melting, they do not move much, Andrews explained. However, they determined that the drumlins featured large grooves, which showed that the ice had to be moving at a fast pace to carve the grooves.

These grooves demonstrated the first evidence of an ice stream in southern Africa in the late Paleozoic Age, which occurred about 300 million years ago.

“The ice carved big, long grooves in the rock as it moved,” Andrews said. “It wasn’t just that there was ice there, but there was an ice stream. It was an area where the ice was really moving fast.”

McGrady used freely available information from Google Earth and Google Maps to measure their length, width and height.

WVU researcher unearths an ice age in the African desert

“This work is very important because not much has been published on these glacial features in Namibia,” said McGrady, a senior geology student from Hamlin. “It’s interesting to think that this was pioneer work in a sense, that this is one of the first papers to cover the characteristics of these features and gives some insight into how they were formed.”

Their findings also confirm that southern Africa was located over the South Pole during this period.

“These features provide yet another tie between southern Africa and south America to show they were once joined,” Andrews said.

The study, “First description of subglacial megalineations from the late Paleozoic ice age in southern Africa” is published in the Public Library of Science’s PLOS ONE journal.

“This is a great example of a fundamental discovery and new insights into the climatic history of our world that remain to be discovered,” said Tim Carr, chair of the Department of Geology and Geography.