Over the past century, 70 percent of beaches on the islands of Kaua'i, O'ahu, and Maui have had long-term erosion, according to a U.S. Geological Survey (USGS) and University of Hawai'i (UH) report released today.
They studied more than 150 miles of island coastline (essentially every beach) and found the average rate of coastal change – taking into account beaches that are both eroding and accreting – was 0.4 feet of erosion per year from the early 1900s to 2000s. Of those beaches eroding, the most extreme case was nearly 6 feet per year near Kualoa Point, East O'ahu.
The "plumbing systems" that lie under volcanoes, the location and behavior of magma chambers on the Earth's mid-ocean ridge system, a vast chain of volcanoes along which the Earth forms new crust, could bring scientists closer to predicting large eruptions.
Researchers worked in Afar (Ethiopia) and Iceland, the only places where mid-ocean ridges appear above sea level. Volcanic ridges (or "spreading centers") occur when tectonic plates rift or pull apart. Magma injects itself into weaknesses in the brittle upper crust, erupting as lava and forming new crust upon cooling.
Magma chambers work like plumbing systems, channeling pressurized magma through networks of underground "pipes".
A chemical analysis of lunar soil collected by Apollo astronauts forty years disputes the belief that a giant collision between Earth and a Mars-sized object gave birth to the moon 4.5 billion years ago.
In the giant-collision scenario, computer simulations suggest that the moon had two parents: Earth and a hypothetical planetary body called “Theia” but a comparative analysis of titanium from the moon, Earth and meteorites indicates the moon’s material came from Earth alone.
ESA’s GOCE gravity satellite has provided us with the first high-resolution map of the boundary between Earth’s crust and mantle – the Mohorovičić discontinuity, or Moho.
Earth’s crust, as you know, is the outermost solid shell of our planet. Even though it makes up less than 1% of the volume of the planet, the crust is exceptionally important not just because we live on it, but because is the place where all our geological resources like natural gas, oil and minerals come from. The crust and upper mantle is also the place where most geological processes of great importance occur, such as earthquakes, volcanism and orogeny.
One of our popular topics last year was earthquakes. That makes sense, with the earthquake in Japan. It's not like there was some greater instance of earthquakes but if you are a Doomsday fearmonger, any event is a good event; that means anti-science activists determined to send us back to the 13th century looked for ways to make earthquakes result from fracking.
If you dispute that, you get meaningless gibberish responses like 'you can't prove the earthquakes did not come from fracking', which is true, in the same way you can't prove I am not the disembodied brain of Adolf Hitler writing this piece from my Antarctic Fortress where I am plotting the Fourth Reich - but it's sort of silly to live your life believing it.
My friend has written a paper on Pantelleria (which I am a co-author of), and I thought it was a good opportunity to discuss some of the techniques we can use to reconstruct a volcano's magma chamber using the petrology (chemistry and texture of the crystals and glass) of the rocks erupted at the surface.
The deadliest mass extinction that we know of, 252 million years ago at the end of the Permian period, took a long time to kill most of Earth's life, and it killed in stages. It wasn't superior to sudden extinctions just because it was gradual.
By the end of the Permian period, Earth was almost a lifeless planet. Around 90 percent of all living species disappeared then, in what scientists have called "The Great Dying." Chemical evidence buried in rocks formed during this major extinction can tell science part of what happened.
A new study in Nature shows that Santorini may have reactivated roughly a century before the Minoan "super-eruption", a lot quicker than had previously been thought. How is it possible to time this awakening?
I have written on here before about magma chambers, and how people initially thought that the chambers of the largest eruptions grew through the slow, incremental process of fractionation
I think most people - certainly myself - get that grim "what, another one?" feeling when you first hear news that there has been a big earthquake.
But is it justified? In other words, have we recently been experiencing an increased rate of earthquakes? This from Beroza (2012),
Welcome to the world's slowest clock.
The 'argon-argon clock' works by measuring the ratio of the amount of radioactive potassium in a sample of rock to the amount of its decay product, argon. As scientists already know the half-life of argon's radioactive decay - 1.25 billion years - it can be used to date rocks back to the time of the formation of the Earth, some 4.5 billion years ago. The older a rock is, the more potassium has decayed and the more argon is found in the rock.
New research has been able to improve the calibration of the 'argon-argon clock' and that could mean up to a 1.2 per cent difference in a rock's age from the original calculation.