May 2014 on EARTH Magazine

Energy Notes: December 2012-2013

Tue, 27 Jan 2015 12:50:10 -0500

Credit: The American Geosciences Institute.

U.S. Oil & Petroleum Imports (million of barrels per day)

Oil and petroleum imports data are preliminary numbers taken from the American Petroleum Institute’s Monthly Statistical Report. For more information visit www.api.org.

Mineral Resource of the Month: Selenium

Tue, 27 Jan 2015 12:44:47 -0500

U.S. Geological Survey selenium commodity specialist Micheal W. George has compiled the following information on selenium, a rare toxic metal.

Brazil nuts contain high levels of selenium. Credit: Gabriela Ramirez Galindo/Center for International Forestry Research.

Selenium, a relatively rare element with diverse uses, is widely distributed within Earth’s crust, but it does not occur in concentrations high enough to justify mining solely for its recovery. Selenium is recovered as a byproduct of nonferrous metal ore processing, principally from the anode slimes associated with electrolytic refining of copper. Slimes from primary copper refining can contain as much as 10 percent selenium, but are generally much lower.

Ancient skeleton found in underwater cave reveals DNA of earliest Americans

Fri, 16 May 2014 12:17:38 -0400

Between 13,000 and 12,000 years ago, a teenage girl entered a cave, likely searching for water, and fell to her death into a pit, which would later fill with glacial meltwater at the end of the last Ice Age. The pit, called Hoyo Negro, Spanish for “Black Hole,” part of the San Actun cave system beneath Mexico’s Eastern Yucatán Peninsula, has now yielded one of the oldest human skeletons ever found in North America.

Recovery of 1960s sea-ice satellite images wins dark data contest

Wed, 14 May 2014 11:19:49 -0400

Visualization of 2010 Arctic sea ice maximum. Credit: NASA.

As part of the Nimbus Data Rescue Project, the NSIDC/NASA team processed and digitized data and images from NASA’s early Nimbus satellites. The earliest images were collected by Nimbus 1 in 1964 as it circled Earth in August and September — the time of year when sea ice reaches its annual minimum and maximum extent in the Arctic and Antarctic, respectively — equipped with little more than a camera. That camera transmitted still photographs of Earth’s surface back to scientists, who filmed the images as they appeared on a TV screen. After being archived for decades, the team was able to scan tens of thousands of photographs, originally used for weather research, and stitch them together with modern software to produce maps of the sea-ice extent surrounding both poles. Resurrection of the Nimbus data thus extended the satellite record of sea-ice extent, which had previously only dated back to 1979, an additional 15 years.

Staking a claim: Deep-sea mining nears fruition

Wed, 14 May 2014 10:51:02 -0400

Credit: Kathleen Cantner, AGI.

In the late 1970s, geologists in a deep-sea submersible several kilometers below the waves on the Galapagos Rift discovered a previously unknown world: hydrothermal vent systems supporting an array of exotic life that thrived in the absence of sunlight, subsisting instead on metals and minerals leached from the seafloor. Such hydrothermal vent systems are now recognized features of mid-ocean ridges.

Mix of acid mine drainage and fracking fluid a recipe for remediation?

Wed, 14 May 2014 10:40:43 -0400

In the Appalachian Basin, “there are hundreds of points where acid mine drainage is discharged to streams. … It’s a nuisance that affects the environment,” says Avner Vengosh, a geochemist at Duke University and a co-author of the new study, published in Environmental Science & Technology. Similarly, flowback water from shale gas operations is bad news if it’s discharged into the environment without being adequately treated, he says, because, after being injected deep underground, it returns to the surface loaded with radium, barium, strontium and other dissolved elements, which can accumulate in stream sediments.

Comment: Preparing for the death of Earth

Wed, 14 May 2014 10:03:55 -0400

Credit: Kathleen Cantner, AGI

About 5 billion years from now, Earth will meet its end in a fiery blaze as it is swallowed by the expanding sun. What happens between now and then, in large part, is up to us and our ability to prepare for the distant future.

Humans causing California's mountains to grow

Wed, 14 May 2014 09:56:28 -0400

A study of more than 500 GPS stations in Southern California and Nevada found an anthropogenic signal in uplift of the Sierra Nevada and the California Coast Ranges related to long-term water withdrawal from aquifers in the San Joaquin Valley. Credit: UNAVCO

Humankind has proven time and again that it can reshape mountains, or even tear them down. Now, it appears, we can make them rise as well. Geologists studying growth rates of the Sierra Nevada and of central California’s Coast Ranges have identified an anthropogenic contribution to the mountains’ uplift that they suggest is tied to the decades-long depletion of groundwater in the state’s Central Valley. What’s more, the researchers report in a study published today in Nature, the long-term water loss may be affecting how stress builds up on faults like the San Andreas.

Reading the walls

Tue, 13 May 2014 13:52:11 -0400

What distinguishes a New England stone wall from a pile of stones? Noted stone wall expert Robert M. Thorson, a geologist at the University of Connecticut, considers a stone wall to be “any continuous row of large stones or stack of smaller ones that is more than four times as long as it is wide.” Anything shorter, he says, “is a cluster or pile of stones, not a wall.”

The history, science and poetry of New England's stone walls

Tue, 13 May 2014 11:24:52 -0400

In 2007, I returned to eastern Connecticut, where I grew up. Driving north on Interstate 395 past towns like Norwich and Griswold, I was struck by the many old gray stone walls tumbling off into the forests along the highway. Realizing that the trees in those forests weren’t particularly old, I surmised that those forests had once been cleared farm lands.

Lessons from the Russian meteor burst

Mon, 12 May 2014 14:53:24 -0400

A 3-D simulation of the Chelyabinsk airburst. Credit: Andrea Carvey, Mark Boslough & Brad Carvey

At about 9:20 a.m. on Feb. 15, 2013, many of those cameras recorded the explosion of a large meteor 23 kilometers above the city. As was widely reported at the time, the air blast shattered windows, and meteorite fragments rained down in and around Chelyabinsk, causing damage to some 7,000 buildings and sending about 1,600 people to hospitals. Although no one was killed, it marks “the first ever asteroid impact disaster in human history,” according to Clark R. Chapman of the Southwest Research Institute (SwRI) Planetary Science Directorate in Boulder, Colo., who presented research on the event at the annual meeting of the American Geophysical Union (AGU) in San, Francisco, Calif., last December.

Down to Earth With: Scott Sampson

Mon, 12 May 2014 14:06:47 -0400

During a recent public lecture at the Denver Museum of Nature and Science, dinosaur paleontologist and evolutionary biologist Scott Sampson was making a point as he walked up the aisle when a preschooler charged the stage, grabbed hold of his leg and wouldn’t let go until her mother retrieved her.

Geologic Column: Riding the rails to Omaha with Rudolf Clausius

Mon, 12 May 2014 13:50:21 -0400

Credit: Ammodramus, public domain.

If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations — then so much the worse for Maxwell’s equations. … But if your theory is found to be against the Second Law of Thermodynamics, I can give you no hope; there is nothing to do but to collapse in deepest humiliation. – Sir Arthur S. Eddington

Benchmarks: May 6, 1852: Edward Sabine links the geomagnetic and sunspot cycles

Mon, 12 May 2014 12:36:59 -0400

Geophysicist and astronomer Edward Sabine (1788–1883). Credit: Bibliothèque Nationale de France, public domain

At the beginning of the 19th century, little was understood about Earth’s magnetic field, but interest in its workings had begun to grow, especially in Europe. That the magnetic field exists had long been recognized, and magnetic compasses had aided in navigation for centuries, particularly at sea where fixed landmarks are hard to come by. Not surprisingly, the increased attention emerging around the turn of the century came from naval and shipping interests, which recognized that an accurate understanding of the field’s behavior would be a boon to their fleets.

Comment: The Oso landslide shows need for insurance and better planning

Mon, 05 May 2014 14:40:56 -0400

Aerial photograph of the upper parts of the Oso landslide that occurred in northwest Washington on March 22, 2014. Credit: Jonathan Godt, USGS.

Prior to March 2014, the Steelhead Drive neighborhood in Arlington, Wash. — on the banks of the north fork of the Stillaguamish River about an hour northwest of Seattle — comprised 45 houses, 25 of which were occupied year-round. Then, just before 11 a.m. on Saturday, March 22, the hill across the Stillaguamish River came tumbling down. More than 7.5 million cubic meters of debris, travelling at velocities up to 100 kilometers per hour, engulfed the community. In minutes, all 45 houses on Steelhead Drive were destroyed, along with nearly half a kilometer of highway SR530. At the time of this writing, 41 people had been declared dead and two were still missing, making the Oso landslide one of the deadliest in American history.

Beyond rocks for jocks: Elevating geoscience education

Fri, 25 Apr 2014 12:54:41 -0400

Credit: Copyright Shutterstock.com/Goodluz

When I was an undergraduate student, all liberal arts students were required to take a science course as a general education requirement. If I recall correctly, the science options were astronomy, biology, chemistry, physical geology and physics. The astronomy, chemistry and physics classes were highly quantitative, which frightened off many general education students. The alternatives of biology and physical geology tended to be more attractive because their core content was less rooted in high-level mathematics. Thus, the physical geology course was a favorite of athletes seeking to fulfill a general education requirement, and for this reason it was called, as it is at many schools, “Rocks for Jocks.”

Getting there and getting around in New Zealand

Thu, 24 Apr 2014 13:58:36 -0400

Auckland, on the North Island, has the country’s largest airport and is the primary international arrival point. The South Island’s largest airports are at Christchurch and Queenstown, but neither hosts direct flights from the U.S.

Travels in Geology: From beaches to bush: Tramping in New Zealand

Thu, 24 Apr 2014 13:30:21 -0400

Credit: Kathleen Cantner, AGI

With its stunningly beautiful landscapes, adrenaline-boosting attractions, renowned wines and craft beers, and easy logistics, New Zealand is one of the world’s foremost tourist destinations. It is especially well known for superb hiking, locally referred to as “tramping” or “bushwalking.” From short strolls through lush temperate rainforest to challenging alpine tracks, New Zealand offers a lifetime’s worth of outstanding walks.

Geomedia: California's climatic catastrophes detailed in "The West Without Water"

Wed, 23 Apr 2014 14:45:55 -0400

On a drought map of California for this past winter, the colors graded from yellow to deep red, indicating drought ranging from abnormally dry to exceptionally dry. The rest of the West is also dry, but the drought epicenter is California, where in January the governor declared an emergency and called for water use reductions to delay the nearly inevitable rationing to come.

Naturally occurring methane found in groundwater in New York

Wed, 23 Apr 2014 14:25:10 -0400

In 2008, when dangerously high levels of methane were found in drinking water wells in Dimock, Pa., fingers were pointed at nearby hydraulic fracturing operations as the source of the contamination. Six years later, the debate still rages over whether the town’s methane problem was exacerbated by drilling operations or if it was there all along. Now a new study is adding some much-needed baseline data for methane levels in groundwater in the natural gas-rich Marcellus Shale region of New York. The results suggest that, in some cases, methane occurs at naturally high levels in groundwater, without the influence of gas exploration and production.

Observing a plate boundary

Wed, 23 Apr 2014 07:48:13 -0400

Credit: UNAVCO

More than 280 continuous GPS (cGPS) stations in Cascadia are part of the U.S. Plate Boundary Observatory (PBO), a component of EarthScope, which includes more than a thousand cGPS stations arrayed across the western United States and Alaska. Operated by UNAVCO, PBO provides continuous data to researchers studying tectonics and earthquakes. Each PBO station operates autonomously to record and transmit up to one sample per second. In addition to PBO, the U.S., New Zealand, Japan and Canada have implemented similar networks of cGPS stations with the intent of capturing both slow and rapid motion. By combining simultaneous data from multiple receivers, scientists can use cGPS networks to produce positioning and ground motion data with millimeter precision. Data from continuous stations can be blended with campaign studies, many of which share a fleet of GPS receivers managed by UNAVCO, to provide an effective tool for seismic research.

A truly global system

Wed, 23 Apr 2014 07:43:02 -0400

Credit: Kathleen Cantner, AGI

Like the GPS navigation system in your car or smartphone, a high-precision GPS receiver uses signals from satellites to determine the distance from the receiver to the satellite. But that’s where the similarities end. Today’s scientific and commercial-grade GPS receivers use two frequencies and carrier phase measurements (distance expressed in units of cycles of the carrier frequency) to produce precise results. In addition to the U.S. GPS satellites, many receivers use data from Russia’s GLONASS navigation satellites and are capable of using signals from the planned European (Galileo) and Chinese (BeiDou) systems. New U.S. satellites will provide an additional third frequency. The combination of the new and existing satellites is collectively known as the Global Navigation Satellite System, or GNSS. GNSS will provide significant benefits to commercial applications such as surveying, agriculture and construction, as well as earth science research.

A new tool for atmospheric studies

Wed, 23 Apr 2014 07:31:18 -0400

Scientists are putting GPS to work in some unexpected new ways. For example, John Braun, a project scientist at the University Corporation for Atmospheric Research (UCAR) in Boulder, Colo., is using GPS to measure precipitable water vapor.

Precise to a fault: How GPS revolutionized seismic research

Mon, 14 Apr 2014 12:57:55 -0400

The Global Positioning System is a constellation of more than 30 satellites orbiting Earth twice a day at an altitude of more than 20,000 kilometers. Geoscientists use GPS to make precise measurements of position and ground motion. Credit: Kathleen Cantner, AGI

In the late 1980s, Ken Hudnut, a Columbia University graduate student studying plate tectonics in Southern California, began experimenting with a new technology, called the Global Positioning System (GPS), as a way to measure the slow, relentless motion of Earth’s crustal plates.

Faking quakes at full scale: Giant shake tables simulate earthquakes to make buildings safer

Fri, 11 Apr 2014 13:29:41 -0400

The largest shake table experiment ever conducted shook this full-size seven-story condominium built at the Japanese National Research Institute for Earth Science and Disaster Prevention's Earth-Defense facility ("E-Defense") in 2009. Credit: John van de Lindt

On a muggy day in mid-July 2009, a lone seven-story condominium complex northwest of Kobe, Japan, was violently shaken by seismic forces similar to those that struck Northridge, Calif., in 1994 — only stronger. Onlookers watched the 23-unit, wood-frame tower sway and bounce while, inside the building, furniture toppled and plates clattered to the floor.

Corals find a way to adapt?

Tue, 12 Nov 2013 20:41:14 -0500

Bleached brain coral. NOAA

A healthy coral reef in the U.S. Virgin Islands. NOAA

In the past few decades, corals around the world have become endangered because of rising water temperatures. However, a new study suggests that corals may be able to adapt to some of that warming.

Scientists demonstrate strengths and shortcomings of method for determining ancient earthquake size

Mon, 09 Sep 2013 15:07:27 -0400

“A giant Cascadia earthquake, with its accompanying tsunami, has the potential to be the biggest natural disaster in this history of the U.S.,” says Simon Engelhart, a seismologist at the University of Rhode Island. On Jan. 26, 1700, a magnitude-9 earthquake associated with the nearby Cascadia Subduction Zone struck the Pacific Northwest. The quake created tsunami waves that left deposits on shorelines as far away as Japan and caused parts of the Pacific shoreline to sink half a meter into the sea. Such a quake will happen again; the question is when. Researchers are attempting to determine how often earthquakes occurred in the past to estimate when the next quake is likely to occur. New experimental research off the coast of Oregon that demonstrates the accuracy of a method for determining the vertical deformation associated with past earthquakes may help scientists answer this question.