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The Ultimate Stress Reliever

Reporting in the journal Science, researchers say they’ve discovered a surprising wrinkle in the geologic story behind one of the most devastating earthquakes in recent memory: the March 2011 Tohoku earthquake that spawned 130-foot tsunami waves, killed 15,800 people and led to a crisis at the Fukushima Daiichi nuclear power plant. The researchers determined that current shear stress on the fault that generated the earthquake is nearly zero. In other words, the violent spasm that released the earthquake also shook out all the pent up stress on the fault. Alan McStravick, writing in a recent article for the website Red Orbit, explained why this was such a shocker: “The paper’s presentation of this fact flies in the face of the prevailing wisdom that earthquakes will typically only release a portion of … Read entire article »

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Earthquake Signals Tectonic Plate Ripping Apart

Three papers in this week’s issue of the journal Nature present startling new findings about an earthquake that struck the Indian Ocean off the coast of Sumatra last April. As reported by Andrea Mustain at Our Amazing Planet, three features of the quake made it unusual: First, it was extremely powerful—at magnitude 8.7, it was the sixth most powerful ever recorded. Second, it struck in the middle of a tectonic plate and not along a plate boundary. Third, when the quake zipped along the initial fault and ran into faults intersecting it at right angles, those intersecting faults ruptured too. Mustain interviewed Thorne Lay, a professor at the University of California, Santa Cruz and co-author of one of the papers: Lay said that, typically, when earthquakes spread to connecting faults, the rupture rips along … Read entire article »

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Desperate Measure Yields Insights for Delta Restoration

In late spring 2011, one of the largest pulses of water in recorded history traveled down the Mississippi River, threatening the ports, industries, farms and towns of the river’s lower reaches, including New Orleans. To avert disaster, the U.S. Army Corps of Engineers opened the Bonnet Carré Spillway and diverted from 10 to 20 percent of the total river flood discharge into Lake Ponchartrain. Jeffrey Nittrouer, a National Science Foundation post-doctoral researcher at the University of Illinois, studied the impacts of the diversion shortly after the floodwaters subsided. Surprisingly, he found that 31-46% of the total sand load carried by the river during the 6 weeks the spillway was open was carried through the spillway. The location of the spillway was not intentionally chosen for delta restoration. But Nittrouer determined its land building power came from the … Read entire article »

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Field Update: Drilling Through the Japan Earthquake Fault

After successfully reentering the wellhead on the edge of the Japan Trench on the seafloor 6926 meters (4.3 miles) below the ship, we began drilling. The goal: to drill ~850 meters (2800 feet) below the seafloor across the plate boundary and through the fault that slipped more than 50 meters (164 feet) at this location during the March 2011 Tohoku earthquake causing the enormous tsunami. We will then try installing a temperature observatory down into the hole to measure the remaining frictional heat across the fault. Instead of using the standard top-drive drilling system on the ship to rotate the entire drill stem and create the torque on the drill bit 7-8 kilometers below, as in the previous drilling at the site, this time we used a mud-motor located just above … Read entire article »

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Field Update: Like Threading a Needle from 7 kilometers away

The goal we are working towards on the JFAST2 expedition is to install an observatory of temperature sensors across the fault zone that slipped more than 50 meters during the March 2011 Tohoku Earthquake. The temperature sensors will allow us to measure the frictional heat and determine the strength of the fault.  To accomplish a critical step of the installation, we must first find the wellhead we installed last May on the seafloor 7 kilometers (4.3 miles) below the ship, reenter it with the drill bit, and then drill down about 850 meters (2800 feet) through the plate boundary fault. The only way we are able to reenter the wellhead on the seafloor, which will allow us to install the observatory into the hole after drilling across the fault, is by … Read entire article »

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Field Update: Return to the Japan Trench

[Editor's Note: Patrick Fulton is a researcher at the University of Texas at Austin's Institute for Geophysics. He was part of an expedition last spring aboard a deep sea drilling ship to study the fault near Japan that unleashed one of the largest earthquakes in recorded history in 2011. That expedition ran into technical difficulties and so now the team has returned to finish the job. For the next few days, Fulton will be sending updates from the ship on the progress of the follow-up expedition. This is his first installment.] Greetings from the scientific deep sea drilling vessel Chikyu and the second part of the Japan Trench Fast Drilling Project: JFAST2 – IODP Expedition 343T. The focus of the JFAST project has been to quickly drill into and study … Read entire article »

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Possible New Human Species Discovered

A new study describes human fossils from southern China that have a blending of modern and archaic features. The fossils date from between 11,500 and 14,500 years ago, a time when it was thought that Neanderthals and all other human species had died out except ours (Homo sapiens). Scientists aren’t sure if the new fossils represent a previously undiscovered human species that lived alongside ours, a group of modern humans that migrated from Africa much earlier than other known migrations, or simply modern humans with unusual features. The report, co-authored by evolutionary biologist Darren Curnoe of the University of New South Wales, appeared online in the journal PLoS One on March 14. The fossilized individuals have been dubbed the Red Deer Cave people after a cave in Yunnan province where several … Read entire article »

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Slumbering Greek Volcano Stirs

Over the past year, Greeks have become accustomed to the feeling of the Earth shifting beneath their feet. Now, it’s not just the economy that’s making them uneasy. Measurements from GPS instruments indicate the ground near the mouth of the island volcano Santorini has deformed by about 2.5 inches since January 2011. In that time, the magma chamber has been growing. The island is what remains of one of the largest volcanic eruptions in recorded history 3,600 years ago. It destroyed Minoan settlements and may have inspired the legend of the lost city of Atlantis. According to a post on LiveScience.com by reporter Stephanie Pappas: If a Santorini eruption did occur, [Andrew] Newman said, it would be nothing like the Minoan eruption of 1650 B.C. that birthed the myth of Atlantis. That eruption … Read entire article »

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Scientists Punch Into Ancient Antarctic Lake

Racing against the oncoming southern winter, Russian scientists announced today they have broken through more than 2 miles of ice to dip into a freshwater lake in eastern Antarctica that had been sealed off from the surface for millions of years. Pressurized water from the lake was allowed to rise up and fill the bore hole before freezing solid. Next year, the scientists plan to return to sample the lake water. They are especially keen to know if microbes are currently living in one of the most extreme environments on Earth. The lake is seen as an analog for a liquid lake or ocean under the icy crust of Jupiter’s moon Europa. In a terrific piece on the much anticipated breakthrough for the New York Times today, David Herszenhorn and James Gorman write that environmentalists are concerned … Read entire article »

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Study: Volcanoes Triggered Little Ice Age

Scientists have debated about what caused the Little Ice Age, an unusually cool period that lasted for several centuries and ended in the late 19th century. Some have suggested it was caused by shiny aerosol particles from volcanoes blocking out a portion of sunlight; others have suggested the sun itself was shining less brightly; or, perhaps a bit of both. Until now, the experts couldn’t even agree on when it started. Estimates of onset have ranged from the 13th to the 16th century. A new study published today in the journal Geophysical Research Letters might settle both questions in one fell swoop. The researchers, led by Gifford Miller, a climate scientist at the University of Colorado, Boulder, say new evidence from northern ice sheets suggests the Little Ice Age was triggered by … Read entire article »

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