Popocatepetl Volcano Erupts In Mexico

MEXICO, (CNN) — The Popocatepetl volcano registered a strong explosion Tuesday evening in the states of Puebla and Morelos, in central Mexico, according to Mexico’s civil protection authority.

The explosion caused lava and ashes to spew, with a smoke plume almost two miles high emanating from the volcano’s dome.

Authorities have asked locals to remain in their homes.

No initial reports of damages or injuries have been reported.

Milky Way’s Neighbors Pick Up The Pace

After slowly forming stars for the first few billion years of their lives, the Magellanic Clouds, near neighbors of our own Milky Way galaxy, have upped their game and are now forming new stars at a fast clip. This new insight into the history of the Clouds comes from the first detailed chemical maps made of galaxies beyond the Milky Way.

Named for explorer Ferdinand Magellan, who led the first European expedition to circumnavigate the globe, the Large and Small Magellanic Clouds are the Milky Way’s nearest galactic neighbors — companion galaxies that will someday merge with our galaxy. The two galaxies are visible only from the Southern Hemisphere, where they look like bright, wispy clouds.

A Map to Stellar History

Although humans have gazed at the Clouds for millennia, this is the first time astronomers have made a detailed map of the chemical compositions of the stars within them. The project, carried out by the Sloan Digital Sky Survey (SDSS), was led by NOAO astronomer David Nidever, who is also a research professor of physics at Montana State University.

“We mapped the positions, movements, and chemical make-up of thousands of stars in the Magellanic Clouds,” said Nidever. “Reading these maps helps us reconstruct the history of when these galaxies formed their stars.”

The maps are the first major discovery to come out of the new southern operations of SDSS’s Apache Point Observatory Galaxy Evolution Experiment 2 (APOGEE-2) survey, which is being carried out on the Irénée du Pont Telescope at Las Campanas Observatory in Chile.

Making Maps from Stellar Spectra

To make the maps, the SDSS team collected spectra of as many stars as possible. Spectra, which spread out the light from a star in the form of a rainbow, encode the motions of stars, their temperature, the chemical elements they contain, and their stage in the stellar life cycle.

By measuring the chemical make-up of a galaxy’s stars, astronomers are able to infer their “star formation history,” a rough record of the rate at which stars formed over time. The reconstruction is possible because of the difference in the lifetimes of stars of different masses and the role more massive stars play in enriching galaxies with heavy elements.

As stars age, stars more massive than the Sun evolve and explode as supernovae, ejecting heavy elements out into the galaxy, while less massive stars live on. The ejected elements mix with the existing gas, enriching it. New generations of stars form from the enriched gas and inherit that chemical make-up. The process repeats, with the longer-lived lower mass stars surviving to record the enrichment history of the galaxy. By mapping the abundances of these stars, astronomers can “read” the star formation record of the galaxy.

Slow Start Followed by a Bang

The results show that the star formation history of the Large and Small Magellanic Clouds is completely different from that of our galaxy. “In the Milky Way, star formation began like gangbusters and later declined,” explained team member Sten Hasselquist from the University of Utah. “In contrast, in the Magellanic Clouds, stars formed extremely slowly at early times, at a rate only 1/50th of the star formation rate in the Milky Way, but that rate has skyrocketed in the last 2 billion years.”

Nidever thinks that the dramatic increase in the star formation rate is due to the interaction of the Magellanic Clouds with one another as they tumble toward the Milky Way. “The Clouds began their lives calmly in a relatively isolated part of the Universe, where there was no reason to form stars,” said Nidever. “But in the last few billion years, the close interactions that the Clouds have had with each other and with the Milky Way is causing the gas in the Clouds to transform into stars.”

Fireworks Ahead!

Over the next several billion years, the Magellanic Clouds will continue to merge with the Milky Way, as the gravitational force of the much more massive Milky Way pulls them in. As the merger progresses, star formation in the Clouds is expected to reach an even greater, fevered pitch, according to recent work. In about 2.5 billion years, the Large Magellanic Cloud will be entirely consumed by the Milky Way in a cosmic explosion of star formation. Our nearest neighbors may have gotten off to a slow start, but exciting times lie ahead!

Deep Freeze Covers Northeast, Midwest After Deadly Weekend Storm

Tens of millions of Americans are feeling the deep freeze left behind by a deadly weekend winter storm that swept through the Midwest and Northeast. More than a quarter of the country woke up to temperatures below 10 degrees Monday, reports CBS News correspondent Omar Villafranca from Killington, Vermont, where the wind chill was minus-31 degrees.

At least 3 deaths are blamed on the severe weather.

The storm also caused headaches for millions of air travelers across the U.S., with thousands of flight cancellations and delays.

Upstate New York got as much as 20 inches of snow. Parts of Ohio and Pennsylvania got up to 18 inches.

The storm buried parts of the Northeast in snow and ice. The Hudson River froze over in upstate New York.

People in Glens Falls, New York, near the Vermont border, spent Sunday digging out from more than a foot-and-a-half of snow, and plows could barely keep up with whiteout conditions on Interstate 87.

In Gray, Maine, residents raced to clear around 8 inches of snow before the Arctic temperatures froze everything. Resident Len Sherwood explained the way to do it is to “do a little bit at a time, go back in warm up, come back out later.”

Connecticut Gov. Ned Lamont said, “What we’re particularly worried about is the icy conditions and what that means to the electric grid.”

The snow, sleet and freezing rain knocked out power to more than 20,000 homes and businesses in Connecticut and New York.

A utility worker in Connecticut was killed Sunday when a tree fell on him while he was trying to restore service.

The storm was deadly from its onset. In Kansas, a snow plow driver died Saturday morning when his vehicle rolled off the road. And it created a scare in Chicago when a United Airlines jet slid off the icy runway after landing at O’Hare Airport.

“Next thing you know we were off the runway and stuck in snow…we ended up sitting on the plane for another hour,” one passenger said.

In Missouri, slick surfaces triggered a 15 car pileup crash on Interstate 55, shutting down the road for hours.

The effects of the storm reached as far south as Alabama, where at least six people were hurt in an apparent EF-2 tornado. Winds topping 135 miles an hour significantly damaged several buildings outside Montgomery.

For those who have to venture out into the bitter cold, the advice is the same whether you’re here skiing or just walking your dog: Dress in layers, stay hydrated, and take frequent breaks inside — because it can take less than 15 minutes for frostbite to set in.

Stromboli Volcano (Italy): Frequent And Strong Explosions From 6 Vents, Observation Report From Close

The activity of the volcano remains elevated – magma is still standing high inside its conduits.

When observed from close earlier today, there were 6 active vents producing intermittent strombolian explosions of small to large size (see annotated image of the crater terrace with the vents indicated as on a map):
The new cinder cone that has been built recently around the NE vent displayed mild and continuous lava spattering with intense lava glow at night, as well as strombolian explosions of small to moderate size (ejection heights racing from few tens of meters to approx. 150 m) at intervals of 10-20 minutes.

The strongest explosions, however occurred from both the easternmost vent (below the more active NE cone, far right in the picture) as well as (and more frequently) from the westernmost vent, both ejecting incandescent material to certainly more than 200 m height and bombs reaching much of the crater terrace and its surroundings. Intervals of explosions were about one every 10-15 minutes vor the western vent and more rarely from the easternmost one (once per 30-40 minutes). As has been typical for the past decades, the westernmost vent usually generated significant amounts of ashes, while all other vents had almost no ash during their explosions.

Some of the most notable eruptions, however, occurred from a vent in the NW area of the crater area: it forms a steep-sided, symmetric, conical shaped small cone and frequently erupted dense, candle-like lava fountains, as well as sometimes only mostly gas jets. Its eruptions were often accompanied by very loud detonation sounds. Occasionally, this vent also produced beautiful “smoke rings” (ring vortexes), apparently caused by pulsating gas emissions from its circular vent.

A small vent just east of the mentioned westernmost vent also erupted in similar, but weaker style (narrow jets of lava) occasionally. Last, the formerly called “central crater”, in the southern central part of the crate terrace also had infrequent, typically small to moderately-sized classic strombolian eruptions. In the past this vent (located in the lower center of the image) often displayed constant glow and spattering, but did not do so today.

All in all, explosions occurred at intervals of about 2-3 minutes from all 6 vents combined.

Strong Magnitude 6.4 Earthquake Strikes Indonesia

A powerful magnitude 6.4 earthquake has struck off Indonesia’s central island of Sumbawa, but no tsunami warning was issued and there were no immediate reports of damage.

The tremor on Tuesday followed a pair of offshore quakes in the same area earlier Tuesday, including one that was magnitude 6.1 south of the city of Raba.

The latest one struck about 85km south of the town of Kahale, according to the United States Geological Survey.

There were no immediate reports of damage or casualties.

Disaster-prone Indonesia, which sits on the geologically active so-called Pacific Ring of Fire, where tectonic plates collide, suffered its deadliest year in more than a decade in 2018 as a series of earthquakes and tsunamis killed thousands of people.

The vast Southeast Asian archipelago of more than 17,000 islands is still reeling from a devastating tsunami at the end of December triggered by an erupting volcano in the middle of the Sunda Strait between Java and Sumatra islands that killed more than 400 people.

The tsunami was Indonesia’s third major natural disaster in six months.

It followed a series of powerful earthquakes on the island of Lombok in July and August and a quake-tsunami in September that killed around 2,200 people in Palu on Sulawesi island, with thousands more missing and presumed dead.

Waves In Saturn’s Rings Give Precise Measurement Of Planet’s Rotation Rate

Saturn’s distinctive rings were observed in unprecedented detail by NASA’s Cassini spacecraft, and scientists have now used those observations to probe the interior of the giant planet and obtain the first precise determination of its rotation rate. The length of a day on Saturn, according to their calculations, is 10 hours 33 minutes and 38 seconds.

The researchers studied wave patterns created within Saturn’s rings by the planet’s internal vibrations. In effect, the rings act as an extremely sensitive seismograph by responding to vibrations within the planet itself.

Similar to Earth’s vibrations from an earthquake, Saturn responds to perturbations by vibrating at frequencies determined by its internal structure. Heat-driven convection in the interior is the most likely source of the vibrations. These internal oscillations cause the density at any particular place within the planet to fluctuate, which makes the gravitational field outside the planet oscillate at the same frequencies.

“Particles in the rings feel this oscillation in the gravitational field. At places where this oscillation resonates with ring orbits, energy builds up and gets carried away as a wave,” explained Christopher Mankovich, a graduate student in astronomy and astrophysics at UC Santa Cruz.

Mankovich is lead author of a paper, published January 17 in the Astrophysical Journal, comparing the wave patterns in the rings with models of Saturn’s interior structure.

Most of the waves observed in Saturn’s rings are due to the gravitational effects of the moons orbiting outside the rings, said coauthor Jonathan Fortney, professor of astronomy and astrophysics at UC Santa Cruz. “But some of the features in the rings are due to the oscillations of the planet itself, and we can use those to understand the planet’s internal oscillations and internal structure,” he said.

Mankovich developed a set of models of the internal structure of Saturn, used them to predict the frequency spectrum of Saturn’s internal vibrations, and compared those predictions with the waves observed by Cassini in Saturn’s C ring. One of the main results of his analysis is the new calculation of Saturn’s rotation rate, which has been surprisingly difficult to measure.

As a gas giant planet, Saturn has no solid surface with landmarks that could be tracked as it rotates. Saturn is also unusual in having its magnetic axis nearly perfectly aligned with its rotational axis. Jupiter’s magnetic axis, like Earth’s, is not aligned with its rotational axis, which means the magnetic pole swings around as the planet rotates, enabling astronomers to measure a periodic signal in radio waves and calculate the rotation rate.

The rotation rate of 10:33:38 determined by Mankovich’s analysis is several minutes faster than previous estimates based on radiometry from the Voyager and Cassini spacecraft.

“We now have the length of Saturn’s day, when we thought we wouldn’t be able to find it,” said Cassini Project Scientist Linda Spilker. “They used the rings to peer into Saturn’s interior, and out popped this long-sought, fundamental quality of the planet. And it’s a really solid result. The rings held the answer.”

The idea that Saturn’s rings could be used to study the seismology of the planet was first suggested in 1982, long before the necessary observations were possible. Coauthor Mark Marley, now at NASA’s Ames Research Center in Silicon Valley, subsequently fleshed out the idea for his Ph.D. thesis in 1990, showed how the calculations could be done, and predicted where features in Saturn’s rings would be. He also noted that the Cassini mission, then in the planning stages, would be able to make the observations needed to test the idea.

“Two decades later, people looked at the Cassini data and found ring features at the locations of Mark’s predictions,” Fortney said.

Nepal Earthquake: Waiting For The Complete Rupture

In April 2015, Nepal — and especially the region around the capital city, Kathmandu — was struck by a powerful tremor. An earthquake with a magnitude of 7.8 destroyed entire villages, traffic routes and cultural monuments, with a death toll of some 9,000.

However, the country may still face the threat of much stronger earthquakes with a magnitude of 8 or more. This is the conclusion reached by a group of earth scientists from ETH Zurich based on a new model of the collision zone between the Indian and Eurasian Plates in the vicinity of the Himalayas.

Using this model, the team of ETH researchers working with doctoral student Luca Dal Zilio, from the group led by Professor Taras Gerya at the Institute of Geophysics, has now performed the first high-resolution simulations of earthquake cycles in a cross-section of the rupture zone.

“In the 2015 quake, there was only a partial rupture of the major Himalayan fault separating the two continental plates. The frontal, near-surface section of the rupture zone, where the Indian Plate subducts beneath the Eurasian Plate, did not slip and remains under stress,” explains Dal Zilio, lead author of the study, which was recently published in the journal Nature Communications.

Normally, a major earthquake releases almost all the stress that has built up in the vicinity of the focus as a result of displacement of the plates. “Our model shows that, although the Gorkha earthquake reduced the stress level in part of the rupture zone, tension actually increased in the frontal section close to the foot of the Himalayas. The apparent paradox is that ‘medium-sized’ earthquakes such as Gorkha can create the conditions for an even larger earthquake,” says Dal Zilio.

Tremors of the magnitude of the Gorkha earthquake release stress only in the deeper subsections of the fault system over lengths of 100 kilometres. In turn, new and even greater stress builds up in the near-surface sections of the rupture zone.

According to the simulations performed by Dal Zilio and his colleagues, two or three further Gorkha quakes would be needed to build up sufficient stress for an earthquake with a magnitude of 8.1 or more. In a quake of this kind, the rupture zone breaks over the entire depth range, extending up to the Earth’s surface and laterally — along the Himalayan arc — for hundreds of kilometres. This ultimately leads to a complete stress release in this segment of the fault system, which extends to some 2,000 kilometres in total.

Historical data shows that mega events of this kind have also occurred in the past. For example, the Assam earthquake in 1950 had a magnitude of 8.6, with the rupture zone breaking over a length of several hundred kilometres and across the entire depth range. In 1505, a giant earthquake struck with sufficient power to produce an approximately 800-kilometre rupture on the major Himalayan fault. “The new model reveals that powerful earthquakes in the Himalayas have not just one form but at least two, and that their cycles partially overlap,” says Edi Kissling, Professor of Seismology and Geodynamics. Super earthquakes might occur with a periodicity of 400 to 600 years, whereas “medium-sized” quakes such as Gorkha have a recurrence time of up to a few hundred years. As the cycles overlap, the researchers expect powerful and dangerous earthquakes to occur at irregular intervals.

However, they cannot predict when another extremely large quake will next take place. “No one can predict earthquakes, not even with the new model. However, we can improve our understanding of the seismic hazard in a specific area and take appropriate precautions,” says Kissling.

The two-dimensional and high-resolution model also includes some research findings that were published after the Gorkha earthquake. To generate the simulations, the researchers used the Euler mainframe computer at ETH Zurich. “A three-dimensional model would be more accurate and would also allow us to make statements about the western and eastern fringes of the Himalayas. However, modelling the entire 2,000 kilometres of the rupture zone would require enormous computational power,” says Dal Zilio.