The 8.8-magnitude earthquake that struck last February relieved seismic stress in some areas–such as southern Santiago–but not in an area dubbed the “Darwin gap,” which lies on the coastal area near Concepcion, according to a study published in the journal Nature Geoscience.
To see if the 2010 quake might have helped release pent-up stress in the Darwin gap, scientists modeled how it might have affected the gap by analyzing tsunami readings gathered by gauges in the water and land observations taken by satellite, GPS and the human eye…. The investigators found the earthquake ruptured only part of the Darwin gap. An area of stored energy remains unbroken there, and the 2010 earthquake might have actually stressed it further…. [Said study coauthor Stefano Lorito]: “A new magnitude 7 to 8 earthquake might be expected in that region.” [OurAmazingPlanet]
The gold ring around your finger may symbolize “till death do us part” for you, but for scientists, it poses a problem.
That shiny band probably cost a small fortune at the jewelry store, but gold is actually abundant on the Earth’s surface (which helps explain why it’s the ideal form of money). The difficulty is, when scientists apply what they know about how the solar system formed, it’s hard to explain how all that gold (and other precious metals that bond easily to iron, like palladium and platinum) got into the Earth’s crust, where bling-loving humans could get at it. A new study in Science sets forth an explanation: In the Earth’s younger days, impacts by huge objects—perhaps even one as big as Pluto—may have brought it here.
To explain this theory, let’s start with the most dramatic impact in our planet’s history: the one that formed the moon and re-melted the solidifying Earth in the process.
Moon rocks brought back during the Apollo missions led to the now widely accepted theory that the moon formed when a Mars-size object crashed into early Earth. Energy from the impact would have spurred the still forming Earth to develop its mostly iron core. When this happened, iron-loving metals should have followed molten iron down from the planet’s mantle and into the core. But we know that gold and other iron-lovers are found in modest abundances in Earth’s mantle. [National Geographic]
At this point, after finding microorganisms that don’t mind extreme temperatures, pressure, aridity and other hardships, we shouldn’t be surprised that bacteria‘s dominion over the Earth extends to just about anywhere we look. A new expedition to the Earth’s crust has reached unprecedented depths—down to the deepest layer of the crust—and found that even there, microorganisms are tough enough to survive.
On a hypothetical journey to the centre of the Earth starting at the sea floor, you would travel through sediment, a layer of basalt, and then hit the gabbroic layer, which lies directly above the mantle. Drilling expeditions have reached this layer before, but as the basalt is difficult to pierce it happens rarely. [New Scientist]
To circumvent the Herculean task of drilling through basalt, the expedition, called the Integrated Ocean Drilling Programme, headed out to sea to find an easier drilling location.
The Integrated Ocean Drilling Program sank its drill into the Atlantis Massif (seen above) in the central Atlantic Ocean where seismic forces have pushed the deep layer, known as the gabbroic layer, to within 230 feet of the ocean floor making it easier to reach. [UPI]
In those volcanoes that kids (or their parents) build for elementary school science fairs, the style is generally simple: There’s one chamber in which the baking soda rests, ready to meet the vinegar and erupt. Most real volcanoes are a little like this, in that they have a single magma chamber that fuels their eruptions.
But not Eyjafjallajökull.
The Icelandic volcano that stirred in March and grounded European air travel has a peculiar kind of plumbing, scientists report today in Nature. Freysteinn Sigmundsson and colleagues combined 20 years’ worth of GPS, satellite, and seismic observations of the volcano see note how it changed over the years—and especially what was happening in the lead-up to this year’s eruption.
What does it take to make a wellspring of biodiversity like the Amazon rainforest? A huge mountain range, a blast of heat, and a little time.
A pair of studies in this week’s edition of Science attempt to sort through tropical natural history and reach the root causes of Amazonia’s embarrassment of biological riches. The first, led by palaeoecologist Carina Hoorn, points to the influence of the Andes Mountains, the spine of South America that runs up its western coast. Sometime between about 35 and 65 million years ago, colliding tectonic plates sent the Andes bulging up. According to the researchers, the birth of a mountain range set of an ecological chain reaction.
The rising mountains that resulted from the uplift blocked humid air from the Atlantic, eventually increasing rainfall along the eastern flank of what became the Andes that eroded nutrient-loaded soils off the mountains. The Andes also kept water from draining into the Pacific, helping form vast wetlands about 23 million years ago that were home to a wide range of mollusks and reptiles. [LiveScience]
A huge spike in the Earth’s atmospheric oxygen about 800 million years ago, the story goes, paved the way for the Cambrian explosion a couple hundred million years later, and with it the rise of complex life. But a new study out in Nature says that picture is incomplete. Researchers found evidence of substantial oxygen 1.2 billion years ago, meaning that the conditions needed for complex life appeared much earlier than scientists knew, and that perhaps something else was required to set off the explosion of biodiversity.
The geologists led by John Parnell hunted in the Scottish Highlands for clues in ancient rocks, where evidence of ancient bacteria could reveal how much oxygen was around 1.2 billion years ago.
Before there was a useful amount of free oxygen around, these bacteria used to get energy by converting sulfate, a molecule with one sulfur atom and four oxygens, to sulfide, a sulfur atom that is missing two electrons. Geologists can get a glimpse of how efficient the bacteria were by looking at two different sulfur isotopes, versions of the same element that have different atomic masses. Converting sulfate to sulfide leaves the rock with a lot more of the isotope sulfur-32 than would be there without the bacteria’s help. [Wired.com]
At 8 a.m. EDT on Nov. 5, Tomas’ center was about 80 miles south-southeast of Guantanamo, Cuba and 160 miles west of Port Au Prince Haiti…. Tomas is moving to the northeast near 10 mph, and is expected to speed up over the next couple of days. [NASA Press release]
The hurricane is currently a category one, with sustained winds of 85 miles per hour, and is expected to continue strengthen throughout Friday before weakening on Saturday. The hurricane’s strong winds and flooding may hit the country hard: Haiti’s earthquake in January left the country particularly susceptible to land slides.
“Haiti has a really serious history of big landslides, almost all of them caused by tropical storm or hurricane rainfall,” said geologist David Petley, the Wilson Professor of Hazard and Risk at Durham University in England. [LiveScience]
If the hurricane stays on its current course it will pass just to the west of the small island nation, but there may still be plenty of damage and human misery. Many Haitians whose homes were destroyed in the earthquake are still living in temporary homes that won’t be able to stand up to the winds.
The retreat of the ice covering “Snowball Earth” 700 million years ago might have been the key to the Cambrian explosion that seeded our planet with diverse forms of life. But the trigger may not have been the changes to the climate, but rather the release of phosphorus into the ocean.
During this time period, called the Cryogenian or Snowball Earth stage, the entire planet was covered in snow and ice, and the oceans may even have been frozen. Many researchers believe that the ice receded twice during this freezing period, first around 700 million years ago and then again around 635 million years ago. In a paper published in Nature this week, a team of researchers propose that these receding sheets released phosphorus into the oceans.
In the scheme offered by [Noah] Planavsky and his colleagues, the snowball ice sheets would, as their modern counterparts do, grind up continental rock that would release phosphorus when the glaciers retreated. That phosphorus would wash into the ocean, where it would fertilize algal blooms that could drive a surge in the production of organic matter and oxygen. And the added organic matter that settled into the mud on the ocean bottom would leave additional oxygen behind, eventually boosting atmospheric and oceanic oxygen. [ScienceNOW]
A huge bounty of amber unearthed in India is giving researchers a peak at the wildlife that inhabited the area 50 million years ago, via the insects that are trapped inside it. The findings, published in the Proceedings of the National Academy of Sciences, suggest that the Indian subcontinent was not as isolated as previously thought.
“We know India was isolated, but … the biological evidence in the amber deposit shows that there was some biotic connection,” says David Grimaldi, curator in the Division of Invertebrate Zoology at the [American Museum of Natural History]. [Press release]
About 150 million years ago, the Indian tectonic plat separated from the African plate and began its 100 million year journey to Asia. During that long journey the subcontinent was isolated from all other continents, giving its wildlife the chance to evolve in distinctly different ways (much like the evolution of marsupials in Australia). Since the amber was deposited in the form of sticky tree resin 50 million years ago, it gives researchers insight into the insects that were adrift on the subcontinent.
“The amber shows, similar to an old photo, what life looked like in India just before the collision with the Asian continent,” says Jes Rust, professor of Invertebrate Paleontology at the Universität Bonn in Germany. “The insects trapped in the fossil resin cast a new light on the history of the sub-continent.” [Press release]