2nd Rockslide In 2 Days Occurs At Yosemite National Park, Injuring 1

A second rock slide in just two days has occurred at Yosemite National Park, injuring one person.

The rockfall happened one day after the first killed one park-goer and injured another Wednesday.

A spokesperson for the park confirmed to ABC News that a significant rock slide released off of El Capitan, a summit above Yosemite Valley, on Thursday.

No fatalities are known at this time, the spokesperson said.

Wednesday’s rockfall also occurred on a popular climbing route on El Capitan. The release point appeared to be near the Waterfall Route on the East Buttress of the summit, according to a press release.

It is currently climbing season at Yosemite National Park, with many park-goers climbing on El Capitan and other routes, according to park officials.

Information on the victims’ identities were not released. Further details were not immediately available.

Maria, Again A Hurricane, Swirls Over North Carolina Beaches

Maria regained strength and became a hurricane again Wednesday, pushing water over both sides of North Carolina’s Outer Banks and taking its time to slowly turn away from the U.S. Atlantic coast.

No injuries have been reported, but the surge of ocean water washed over eroded beaches, flooding properties and state Highway 12, the only road through the narrow barrier islands of Hatteras and Ocracoke.

No ferries were moving, cutting off access to Ocracoke, and with parts of the highway flooded even at low tide, any travel on Hatteras remains hazardous, Dare County Emergency Management Director Drew Pearson said in an email. He said the worst problems were on Hatteras Island, where more than 10,000 visitors left under an evacuation order, but hundreds of local residents were allowed to stay.

The National Hurricane Center said an Air Force Reserve reconnaissance aircraft measured Maria’s top sustained winds at near 75 mph (120 kmh), with higher gusts. Its center was about 180 miles (290 kilometers) off Cape Hatteras at 2 p.m. Wednesday.

While Maria’s most punishing hurricane-force winds remained offshore, tropical storm-force winds extended for as much as 230 miles (370 kilometers) from the center, churning up the surf on both sides of the islands. The hurricane’s forward speed is just 6 mph (9 kph), so the storm was lingering before swinging out to sea.

On Hatteras, a fine rain fell Wednesday, with patches of blue sky occasionally showing through. Police set up a check point to block all traffic except for residents and reporters. As the winds picked up, waves crashed up to and beyond ocean-front homes between the communities of Rodanthe and Avon, where the water has washed under waterfront homes and onto side streets since Tuesday at high tide.

“Mother Nature keeps chopping at it,” said Tony Meekins, 55, a lifelong resident of Avon who works as an engineer on the temporarily halted Hatteras-Ocracoke ferry. “We see storm after storm.”

Standing near Avon’s closed fishing pier, Meekins pointed to where the dune line is gone, pounded down by previous storms. At low tide, a layer of wet sand covered the road.

Chip Stevens owns Blackbeard’s Lodge, a 38-unit hotel on Ocracoke. He hopes the highway remains passable on both islands to enable the people and supplies that arrive by ferry to move up and down the island.

This weather is only the latest tropical blow to the Outer Banks, among the most fragile islands in the continental United States. Officials warned that the surge of ocean water and waves would overwhelm sand dunes from both the ocean and from Pamlico Sound, which separates the islands from the mainland. Bulldozers were in place to push the sand off Highway 12 when water subsides.

That said, Texas, Florida, several small Caribbean islands and Puerto Rico have all seen worse this year. Puerto Rican officials said electrical power may not be fully restored for more than a month after the grid was destroyed by Maria’s Category 4 hurricane winds last week. More than 3 million of the island’s U.S. citizens still lack adequate food, water and fuel.

Maria is predicted to erode more than half the dunes along North Carolina’s 300-mile (485-kilometer) coast. Beaches in Maryland and Virginia could fare even worse, with two-thirds seeing erosion and the ocean washing over the dunes on one-third of them, according to the U.S. Geological Survey.

All that salt water “is like throwing battery acid on your car,” said Carrington Erhardt, who worries about driving to the homes she cleans. “That’s the biggest thing, is that it destroys the vehicles.”

Brent and Donna Bennett, of Buxton, worry about lost wages. He works at an ice cream shop, which is closed, and she can’t make it through the floods to her hotel desk job in Hatteras Village.

“Storms are something you come to expect. We seem to have more of our share recently, and I’m over it,” Donna Bennet said.

Hurricane Lee, meanwhile, strengthened to a major Category 3 hurricane in the open Atlantic, where it was swinging north and east before damaging winds could reach Bermuda.

Lost Continent Of Zealandia: Scientists Return From Expedition To Sunken Land

After a nine-week voyage to study the lost, submerged continent of Zealandia in the South Pacific, a team of 32 scientists from 12 countries has arrived in Hobart, Tasmania, aboard the research vessel JOIDES Resolution.

Researchers affiliated with the International Ocean Discovery Program (IODP) mounted the expedition to explore Zealandia. IODP is a collaboration of scientists from 23 countries; the organization coordinates voyages to study the history of the Earth recorded in sediments and rocks beneath the seafloor.

“Zealandia, a sunken continent long lost beneath the oceans, is giving up its 60 million-year-old secrets through scientific ocean drilling,” said Jamie Allan, program director in the U.S. National Science Foundation’s Division of Ocean Sciences, which supports IODP.

“This expedition offered insights into Earth’s history, ranging from mountain-building in New Zealand to the shifting movements of Earth’s tectonic plates to changes in ocean circulation and global climate,” Allan said.

Earlier this year, Zealandia was confirmed as Earth’s seventh continent, but little is known about it because it’s submerged more than a kilometer (two-thirds of a mile) under the sea. Until now, the region has been sparsely surveyed and sampled.

Expedition scientists drilled deep into the seabed at six sites in water depths of more than 1,250 meters (4,101 feet). They collected 2,500 meters (8,202 feet) of sediment cores from layers that record how the geography, volcanism and climate of Zealandia have changed over the last 70 million years.

According to expedition co-chief scientist Gerald Dickens of Rice University in the U.S., significant new fossil discoveries were made. They prove that Zealandia was not always as deep beneath the waves as it is today.

“More than 8,000 specimens were studied, and several hundred fossil species were identified,” said Dickens.

“The discovery of microscopic shells of organisms that lived in warm shallow seas, and of spores and pollen from land plants, reveal that the geography and climate of Zealandia were dramatically different in the past.”

The new discoveries show that the formation 40 to 50 million years ago of the “Pacific Ring of Fire,” an active seafloor zone along the perimeter of the Pacific Ocean, caused dramatic changes in ocean depth and volcanic activity and buckled the seabed of Zealandia, according to Dickens.

Expedition co-chief scientist Rupert Sutherland of Victoria University of Wellington in New Zealand said researchers had believed that Zealandia was submerged when it separated from Australia and Antarctica about 80 million years ago.

“That is still probably accurate, but it is now clear that dramatic later events shaped the continent we explored on this voyage,” Sutherland said.

“Big geographic changes across northern Zealandia, which is about the same size as India, have implications for understanding questions such as how plants and animals dispersed and evolved in the South Pacific.

“The discovery of past land and shallow seas now provides an explanation. There were pathways for animals and plants to move along.”

Studies of the sediment cores obtained during the expedition will focus on understanding how Earth’s tectonic plates move and how the global climate system works. Records of Zealandia’s history, expedition scientists said, will provide a sensitive test for computer models used to predict future changes in climate.

Geologists Study The Drying Up Of The Mediterranean Sea 5.96 Million Years Ago

We already know that climate change influences such Earth processes as erosion and fluctuations in sea levels. But do surface processes in turn have an influence on volcanic activity? This was the question raised by geologists from the University of Geneva (UNIGE, Switzerland) and international collaborators. The researchers analysed volcanic data from the Messinian salinity crisis in the Mediterranean Sea, when the Strait of Gibraltar was blocked and the Mediterranean temporarily isolated from the Atlantic. After observing a sharp rise in volcanic activity during this period, and testing various scenarios, the geologists concluded that the increase in magmatic activity could only be explained by the almost total drying out of the Mediterranean. These results, published in Nature Geoscience, reveal the influence of surface processes, largely controlled by climate, on volcanic activity.

It is known that the Strait of Gibraltar was temporarily shut during the Messinian Era (more precisely, from 5.96 to 5.33 million years ago) and that the Mediterranean Sea was isolated from the Atlantic. In fact, as far back as the 1970s, scientists have found layers of salt several hundred metres thick on the seabed. The only explanation is that there was very limited connection between the Mediterranean and the Atlantic. The scientists also discovered huge underwater canyons dating back to the same period, hollowed out by rivers running over land that is now submerged, suggesting that the sea level was much lower at the time. This also points to the massive drying up of the Mediterranean with enormous geographical and climatic disruption across the entire basin. This hypothesis, however, continues to be a source of debate.

Nevertheless, a team of UNIGE-led geologists has provided new evidence of the Mediterranean’s drying up and the forcing of surface processes on magmatic activity. “We understand that what happens at the Earth’s surface, such as a sudden sea level lowering, causes the pressure to change at depth and has an effect on magma production,” says Pietro Sternai, researcher in the Department of Earth Sciences in UNIGE’s Science Faculty. Given that the salinity crisis was capable of generating these changes in pressure, the geologists, working on the hypothesis that the Mediterranean dried out, studied the changes in volcanic activity during this period.

When a volcano erupts, the magma cools on the Earth’s surface and the minerals crystallise. Based on these silent witnesses of volcanic activity, the scientists were able to establish that there were 13 eruptions around the Mediterranean between 5.9 and 5.3 million years ago. This is over twice the average activity, which is around 4.5 eruptions over a longer time length encompassing the salinity crisis. Why is the figure so high? “The single logical explanation,” suggests Sternai, “is the hypothesis that the sea dried out, since this is the only event powerful enough to alter the Earth’s pressure and magmatic production over the entire Mediterranean.”

The geologists used numerical models to test the hypothesis that the Mediterranean dried up. They reproduced the history of the charging and discharging of the weight of water and sediment in the Mediterranean as it was drying out. Then they calculated the changes in pressure at depth and the impact on magma production.

Two scenarios were examined: The first factored in the salinity crisis with drastic lowering of the sea level, and the second excluded the drawdown. “The simulations showed that the only way to account for the proven increase in volcanic activity was that the level (and thus the weight) of the Mediterranean Sea dropped by about two kilometres,” explains Sternai. “I leave it to you to imagine what the landscape looked like.”

In addition to providing further evidence of the drying out of the Mediterranean, the research also demonstrates the impact of climate change on the deep Earth. Climate change influences magmatic production, in particular via the effects on erosion and hydrology, which modify the pressure exerted at the Earth’s surface on the deep layers. Although we have been aware of the impact of volcanism on the climate for quite some time, the results presented in the study have disclosed that the opposite is also possible. “This pioneering work opens up new perspectives for interdisciplinary studies about the coupling between the solid Earth and the fluid Earth, and—for example—involving volcanologists, geomorphologists and climatologists,” concludes Sternai.

The Material That Obscures Supermassive Black Holes

Cristina Ramos Almeida, researcher at the IAC, and Claudio Ricci, from the Institute of Astronomy of the Universidad Católica de Chile, have published a review in Nature Astronomy on the material that obscures active galactic nuclei obtained from infrared and X-ray observations.

Black holes appear to play a fundamental role in how galaxies evolve during a phase in which they are active and consuming material from the galaxy itself. During this phase, the galaxy hosts an active galactic nucleus (AGN), and the effect that this nuclear activity produces in the galaxy is known as AGN feedback. For instance, the AGN can heat, disrupt, consume and remove the gas available to form new stars, preventing further galaxy growth. AGN feedback is now required by simulations of galaxy formation to explain the observations of massive galaxies at cosmological distances. “If AGN feedback is not accounted for in the simulations,” explains Cristina Ramos, “the predicted number of massive galaxies when the universe was younger is much higher than those that are observed.”

Directly studying the influence of nuclear activity on galaxy evolution is challenging because of the different spatial scales and timescales involved in the two processes. Massive galaxies host extremely compact supermassive black holes of millions or even billions of solar masses in their nuclei. It is estimated that the phases of nuclear activity last for a short period of time, between 1 and 100 million years, whereas galaxy evolution processes, such as bulge growth or bar formation, last much longer. “In order to study the connection between the AGN and the host galaxy, we need to look at the nucleus of galaxies, where the material that links them is found. This material consists mainly of gas and dust, which are normally studied in the infrared and X-ray band,” explains Claudio Ricci.

The astrophysicists offer a comprehensive view of the current understanding derived from infrared and X-ray studies. These have greatly improved in the last decade thanks to observing facilities such as CanariCam on the Gran Telescopio CANARIAS (GTC), located at the Roque de los Muchachos Observatory (Garafía, La Palma) and the Very Large Array Interferometer (VLTI) in the infrared range, as well as X-ray satellites like NuSTAR, Swift/BAT and Suzaku.

Cristina Ramos says, “We now know that this nuclear material is more complex and dynamic than we thought a few years ago: It is very compact, formed by gas and dusty clouds orbiting the black hole, and its properties depend on the AGN luminosity and accretion rate. Moreover, it is not an isolated structure, but appears connected with the galaxy via outflows and inflows of gas, like streams of material flowing as part of a cycle. This gas flow cycle keeps feeding the black hole and regulates the formation of new stars in the galaxy.”

Recently, the Atacama Large Millimeter/submillimeter Array (ALMA) has imaged the nuclear obscuring material in an active galaxy for the first time. ALMA operates in the millimiter and sub-millimeter range, and the latter traces the coolest dust and gas surrounding AGN. In the case of the galaxy NGC 1068, ALMA has shown that this material is distributed in a very compact disc-like shape of seven to10 parsecs (pc) in diameter, and in addition to the regular rotation of the disk, there are non-circular motions that correspond to high-velocity gas outflowing from the galaxy nucleus. “Over the next decade, the new generation of infrared and X-ray facilities will contribute greatly to our understanding of the structure and physical properties of the nuclear material,” concludes Claudio Ricci.

New Study May Help Identify Areas With And Without Accessible Water Ice On Mars

New findings reveal deposits on Mars that could be interpreted to be ice-rich may contain little or no ice at all, based on an analysis of radar sounder data for Meridiani Planum—an area on the planet’s equator being explored by the Opportunity rover.

This new insight into Meridiani Planum may help identify areas with and without accessible water ice, a resource critical to future human exploration and possible colonization of Mars. A new paper detailing the findings is published in Geophysical Research Letters, a journal of the American Geophysical Union.

In the new study, researchers present new compaction models for materials on Mars that suggest the electrical properties of the deposits of Meridiani Planum, derived from data collected by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument, can be explained without the need for pore-filling ice.

The MARSIS instrument transmits low-frequency radio pulses that penetrate certain geologic materials and are reflected back where the radio pulses encounter a change in bulk density or composition of the materials. The detection of subsurface reflectors can be used to determine the dielectric constant, a key electrical properties of the materials, by measuring the travel time delays between radar pulses reflected by the surface and subsurface interfaces in Meridiani Planum.

This analysis indicates that the deposits of Meridiani Planum have a relatively low dielectric constant. Pure water ice has a low dielectric constant and deposits on Mars with low dielectric constants are often interpreted to be ice-rich.

However, newly derived compaction models for Mars indicate that the derived, relatively low dielectric constant of the Meridiani Planum deposits are consistent with a thick sequence of ice-free, porous, windblown sand. Unlike other geologic materials that have been suggested for Meridiani Planum such as volcanic ash or silicate dust, a thick deposit of sand-sized particles on Mars does not compact nearly as much.

“It’s very revealing that the low dielectric constant of the Meridiani Planum deposits can be explained without invoking pore-filling ice,” said Thomas R. Watters, a planetary scientist in the Center for Earth and Planetary Studies at the National Air and Space Museum in Washington, D.C. and lead author of the new study. “Our results suggest that caution should be exercised in attributing non-polar deposits on Mars with low dielectric constants to the presence of water ice.”

Large Meteorite Impacts Drove Plate-Tectonic Processes On The Early Earth

An international study led by researchers at Macquarie University has uncovered the ways in which giant meteorite impacts may have helped to kick-start our planet’s global tectonic processes and magnetic field. The study, being published in the premier journal Nature Geoscience, explores the effect of meteorite bombardment, in geodynamic simulations of the early Earth.

“Our results indicate that giant meteorite impacts in the past could have triggered events where the solid outer section of the Earth sinks into the deeper mantle at ocean trenches – a process known as subduction. This would have effectively recycled large portions of the Earth’s surface, drastically changing the geography of the planet,” explained lead author Associate Professor Craig O’Neill from Macquarie University.

“Large impact events may have also kick-started the Earth’s magnetic field by triggering the planet’s cold outer crust to suddenly move downward and interact with the Earth’s outer core. This affects convection in the core, and thus the geodynamo – the process that creates the Earth’s magnetic field,” he added.

To date, there is still not clear evidence to show whether plate tectonics operated in Earth’s early history, with the first 500 million years of our planet’s life, called the Hadean, often being dubbed as Earth’s geological dark ages. The little crust that has been preserved from this elusive period – mostly single grains of a mineral called zircon – has been used to argue for early tectonic activity. However, this is at odds with geochemical data and geodynamic simulations, which suggest that the Earth may instead have had a motionless ‘lid’ on its surface – in contrast to the actively moving combination of plates we see today.

“We know that meteorite impacts had a huge effect on the inner solar system at this time,” says Associate Professor O’Neill, “you only need to look at the Moon to see that. What isn’t clear was how our own impact history might have affected the planet’s evolution.”

“We’ve seen evidence of some geological activity that suggests something like subduction acted on the early Earth – but this is hard to reconcile with other geodynamic simulations. But if we consider Earth as part of an evolving early solar system, as opposed to only looking at the planet in isolation, then this evolution starts to make more sense,” he added.

O’Neill also notes that while the magnetic field for much of Earth’s ancient history has been quite low, but recent work has suggested field strengths up to present-day values existed between around 4.0-4.1 billion years ago.
“This is a really important age in the inner solar system. Impacting studies have suggested a big disturbance in the asteroid populations at this time, with perhaps a big upswing in impacts on the Earth. Our simulations show that larger amounts of meteorite collisions with the planet around this time could have driven the subduction process, explaining the formation of many zircons around this period, as well as the increase in magnetic field strength.”

Overall, the study adds evidence towards the fact that meteorite impacts likely had a role in the formation of the Earth that we know today.

“This work shows there is a strong connection between impacts and geophysical evolution capable of drastically altering a planet’s evolution,” said coauthor Dr Simone Marchi from the Southwest Research Institute in the USA.

“One has to wonder, how much of the current Earth, and other terrestrial planets, is the result of collisions that took place eons ago?” Dr Marchi concluded.