May 2015 on EARTH Magazine

Energy Notes: October 2013-2014

Mon, 18 Jun 2018 16:53:48 -0400

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: Graphite

Tue, 12 Jun 2018 14:46:48 -0400

Donald W. Olson, a mineral commodity specialist for the U.S. Geological Survey, compiled the following information on graphite, which is used in many industrial applications because of its unique properties.

In 2004, physicists Andre Geim and Konstantin Novoselov used cellophane tape to extract a single-atom-thick layer of graphene from graphite and transferred it to a silicon wafer — work for which they won the 2010 Nobel Prize in Physics. Geim donated this signed tape dispenser to the Nobel Museum. Credit: Gabriel Hildebrand, Nobelmuseet

Graphite is one of four natural forms of crystalline carbon, along with carbon nanotubes, diamonds and fullerenes. It is gray to black in color, opaque and usually has a metallic luster, although it sometimes exhibits a dull earthy luster. Graphite is soft, flexible, low-density, chemically inert and highly refractory. It is the most electrically and thermally conductive of the nonmetals.

Counting 'tree' rings in fish skulls provides climate clues

Fri, 29 May 2015 12:56:07 -0400

Most fish have little structures in their skulls that record growth patterns — periods of feast and famine — just like tree rings. Now, scientists are using these structures, called otoliths, to show how fish size may decrease as a result of a changing ocean.

California's big trees dying of thirst

Thu, 28 May 2015 13:24:12 -0400

Since the early 20th century, the abundance of big trees has declined in forests across California, including in the Sierra Nevada. Credit: Jodie Wilson, CC BY 2.0

From the days of John Muir’s treks through the sylvan valleys and granite peaks of the Sierra Nevada, California’s majestic forests have attracted nature lovers from around the world. Since Muir’s death in 1914, though, dramatic changes have taken hold. Across the state’s forests, small trees are more common while large trees have declined in number, and oaks seem to be taking over where pines once ruled. A new study cites drought due to warming as a major driving force behind these changes.

Geomedia: On the web: Personalizing drought data with digital tools

Tue, 26 May 2015 13:14:19 -0400

California's current drought has been one of the worst since record-keeping began. Credit: Megan Sever.

With drought, people feel the heat while it’s happening, but understanding how current droughts fit into past trends — and what they mean for the future — is harder to grasp. Several online tools are available to help the public and decision-makers make sense of drought data. Viewers can see current and historical droughts superimposed on maps, focusing in on specific locations or broadening the view to larger regional, national or global droughts.

Megafloods mostly shaped Icelandic canyon landscape

Fri, 22 May 2015 11:54:45 -0400

In the 1920s, geologist J Harlen Bretz proposed that cataclysmic glacial megafloods had dramatically transformed the landscape of the northwestern U.S., leaving behind distinctive landforms like the channeled scablands in eastern Washington. Though Bretz’s notion, initially controversial, has long since been accepted, resolving how much landscapes are shaped by extreme events as opposed to the slow action of everyday erosion has nonetheless remained difficult.

Pre-settlement erosion rates illuminated

Tue, 12 May 2015 10:05:26 -0400

Researchers quantified background landscape erosion rates in the southeastern U.S. prior to European settlement by studying sediments along 10 major rivers, including the Dan River. Credit: ©MarmadukePercy, CC BY-SA 3.0.

Humans are one of the most powerful erosive agents on Earth, moving copious amounts of sediment to and fro, mainly through agriculture and development. But quantifying how much we actually move — often a necessary step for developing sustainable land management practices — hinges on determining erosion rates in an area before humans intervened. A new study using surface exposure dating to estimate pre-colonial erosion rates in the southeastern U.S. has now clarified the natural background rate in more detail than ever before, revealing the dramatic human impact on the regional landscape.

Energy Notes: November 2013-2014

Fri, 08 May 2015 12:47:52 -0400

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: Iron oxide pigments

Fri, 08 May 2015 12:41:09 -0400

Arnold O. Tanner, a mineral commodity specialist for the U.S. Geological Survey, compiled the following information on iron oxide pigments.

Prior to the 2011 royal wedding, the roads and walkways around Buckingham Palace in London were resurfaced with stone mastic asphalt dyed red with a synthetic iron oxide pigment. Credit: ©Misterweiss.

Iron oxide pigments, natural or synthetic, are inorganic materials commonly used as coloring agents. They are valued for their resistance to color-change (especially from exposure to sunlight), chemical resistance, stability under ambient environmental conditions, nontoxicity and relatively low cost.

Comment: The new frontier: Homesteading on Mars

Fri, 08 May 2015 12:08:45 -0400

Photograph of Mars taken by the Hubble Space Telescope during opposition in 2003. Credit: Public Domain.

Escalating scientific interest in Mars and ambitious plans to send humans to the Red Planet in the near future raise critical questions about how extraterrestrial colonizations might be governed and how humans can best utilize the resources of space.

Down to Earth With: Marine Geophysicist Maya Tolstoy

Fri, 08 May 2015 11:38:09 -0400

Marine geophysicist Maya Tolstoy is an associate professor at Columbia University's Lamont-Doherty Earth Observatory. Credit: LDEO.

Growing up in Scotland, Maya Tolstoy was drawn to the theater, and even briefly considered majoring in the subject in college. Instead, she chose to follow another lifelong passion and became a marine geophysicist.

Geologic Column: On the Summer Solstice

Thu, 07 May 2015 15:22:03 -0400

There is no world organization that designates the official days on which seasons begin. In fact, there are different ideas about how to define the seasons. When I was a child, summer began, for my friends and me, at 3 p.m. on the last day of school. Meteorologists and climatologists may tell you that summer begins on June 1. Astronomers, however, use the summer solstice — which falls this year on Sunday, June 21 — to mark the beginning of summer in the Northern Hemisphere and the beginning of winter in the Southern Hemisphere.

Getting there and getting around in South Australia

Thu, 07 May 2015 14:45:34 -0400

Most vineyards in the South Australian wine region welcome visitors to "cellar door" tasting rooms. Credit: all: Terri Cook and Lon Abbott.

Adelaide, South Australia’s largest airport, doesn’t host direct flights to and from the U.S., but it is well connected to Sydney, Australia’s primary international arrival point, and other Australian cities. From the airport, you can take a taxi, a metro JetBus, or a Skylink minibus (www.skylinkadelaide.com) to get into town.

Travels in Geology: Glaciers and grapes in South Australia

Thu, 07 May 2015 10:58:17 -0400

Hallett Cove Conservation Park near Adelaide, Australia, exhibits evidence of a Permian glaciation that occurred when Australia lay at 70 degrees south latitude. Credit: Terri Cook and Lon Abbott.

Without an architecturally stunning opera house, an expansive colorful reef or an iconic redrock outcrop to boast, Adelaide is not usually considered one of Australia’s top travel destinations. But because we love Earth history as well as wine, this town on the southern coast was at the top of our Australian travel itinerary when we found ourselves on sabbatical near Sydney last year. Adelaide is a cosmopolitan city of manageable size, replete with stunning beaches and an especially accessible yet rugged corner of the Outback nearby. Best of all, visitors can observe the handiwork of successive glaciations — which covered the region between 700 million and 280 million years ago — while en route from one cellar door to the next as they tour a world-class South Australian wine region in the picturesque hills just minutes from the city.

Comparing apples to oranges, hyenas to humans

Tue, 05 May 2015 09:34:18 -0400

Studying the behavior and social structure of living carnivores, such as spotted hyenas, might shed light on whether early humans led cooperative lives. Credit: David S. Green.

Traditionally, anthropologists thought that hunting played a huge role in the lives of early humans, perhaps because of the prominence of stone tools in the fossil record. But today, most researchers recognize that hominids must have exploited a wide range of resources, and were probably not exclusively carnivores.

The new anthropology: From bones and stones to biology and behavior

Tue, 05 May 2015 09:25:52 -0400

Grasslands in Tanzania's Serengeti National Park in East Africa may be similar to some of the habitats in which early humans evolved. Credit: ©Noel Feans, CC BY-2.0.

Paleoanthropology has traditionally been a dusty science, with new discoveries usually involving bones, teeth and stone tools painstakingly picked from the dirt. But in recent years, the field has embraced a more integrated approach to understanding our ancestors, studying them not just in terms of their skeletons and artifacts, but also their biology and behavior as formerly living, breathing organisms.

And best picture goes to...'Dante's Peak'

Tue, 05 May 2015 09:14:12 -0400

In the 1997 movie "Dante's Peak," one of the more accurate portrayals of geologists at work, Pierce Brosnan plays USGS volcanologist Harry Dalton. Credit: ©Universal Studios via Movie Stills Database.

Our favorite cult geologist movie is “Dante’s Peak,” released in 1997. It is a good representation of the last few decades of disaster movies, and it is arguably the best and most realistic geologist movie to date.

Rock stars: Geologists on the silver screen

Mon, 04 May 2015 13:24:32 -0400

Credit: K. Cantner, AGI.

When geologists gather for a beer after work or around a campfire after a long day in the field, the conversation sometimes turns to how our profession is portrayed on film. Are geologists heroes or villains? Do they appear only in supporting roles — their parts limited to entering an office, uttering “Drill here,” and promptly leaving the scene — or are they main characters?

Flames fan lasting fallout from Chernobyl

Mon, 04 May 2015 13:08:03 -0400

Forest fires in the Chernobyl Exclusion Zone have the potential to spread radioactive contamination as far as Turkey and Scandinavia. Credit: ©Hrebenjuk Oleksandr, CC BY-NC-SA 2.0.

On April 26, 1986, the Chernobyl nuclear power plant in Ukraine exploded during a catastrophic meltdown, spewing radioactivity over Eastern Europe and forcing evacuations of thousands of people. Nearly 30 years later, the scar of the Chernobyl disaster remains in Belarus, Russia and Ukraine in the form of the 2,600-square-kilometer Exclusion Zone, which is choked with dead trees and overgrown brush contaminated with high levels of radioactive cesium, strontium and plutonium. Occasional wildfires in these woods send plumes of smoke laced with potentially harmful radionuclides into the atmosphere. Now, a new study finds that climate change will likely increase the frequency and intensity of these fires, further increasing the possible hazard.

Amber-encased plant could be oldest known grass: Specimen may also preserve a Cretaceous-aged hallucinogen

Mon, 04 May 2015 12:52:54 -0400

This 100-million-year-old amber-encased specimen contains what could be the oldest grass fossil known, and the only fossilized specimen of the fungus ergot (dark material at top) ever found. Credit: Oregon State University.

Delicate grasses don’t preserve well in the fossil record, and evidence for grasses coexisting with dinosaurs is scant. But according to a new study, a chunk of 100-million-year-old amber recently discovered in Myanmar appears to contain the world’s oldest grass fossil — far more ancient than any fossil grasses previously found. What’s more, the specimen seems to be topped with the world’s oldest known ergot — a fungus containing ingredients used to make lysergic acid diethylamide, better known as LSD. But while the image of a 100-metric-ton sauropod grazing on hallucinogen-laced grass is intriguing, not everybody is convinced that the specimen is the real deal.

Where on Earth? - May 2015

Fri, 01 May 2015 12:05:49 -0400

Scroll down for the answer

Clues for May 2015:

Sharing its name with a mountain peak, river, lake and town, the glacier seen in the distance here is one of six large outlets, or tongues, of a major icefield that covers roughly 300 square kilometers and straddles a continental divide.
With its proximity to a nearby highway, appropriately dubbed the “Icefields Parkway,” and easy accessibility to visitors on foot, it is thought to be the most visited glacier on its home continent.
Even though the icefield receives an average of 7 meters of snow annually and the glacial ice moves downslope at a rate of several centimeters per day, the glacier’s terminus recedes roughly 5 meters per year.

Red Planet Roundup: May 2015

Mon, 20 Apr 2015 12:07:24 -0400

Small solar-powered helicopters, like that depicted in this artist's drawing, might accompany future rover missions on Mars, flying ahead to scout terrain and help operators on Earth plot better routes. Credit: NASA/JPL-Caltech.

With two rovers patrolling the surface of Mars, five spacecraft in orbit above it, and scientists back here on Earth studying the Red Planet from afar, new findings are announced almost weekly. Here are a few of the latest updates.

Ancient moss reveals tsunami timing

Mon, 20 Apr 2015 11:54:15 -0400

The moss found in the tsunami deposit, called Hylocomium splendens, sprouts a new growth segment in the spring that grows until autumn. Credit: Knut Rydgren.

Fishermen trawling Norway’s waters have long known of a place where the seafloor drops precipitously into the abyss. It’s called Storegga — or “great edge” — and it’s actually the steep headwall of the largest undersea landslide in recent geologic history. The slide triggered a tsunami that flooded the shores of the North Sea, reaching as far as Greenland, and likely affecting the Stone Age people that inhabited Northern Europe at the time.

More warming may mean more lightning

Mon, 20 Apr 2015 11:49:40 -0400

The continental U.S. will see more lightning in the future as storm energy and precipitation rates rise with global warming, according to new research. Credit: ©Lyoha123, CC BY-SA 3.0.

Add more lightning to the list of predicted effects of climate change. A recent study in Science forecasts a significant increase in the number of lightning strikes within the continental United States over the next century.

A decade of slow slip may have preceded Japan's 2011 earthquake

Mon, 20 Apr 2015 11:44:10 -0400

Shaking intensities (based on USGS data) on Honshu Island during the 2011 Tohoku earthquake in Japan. Warmer colors indicate greater intensity. Credit: NASA Earth Observatory Image by Jesse Allen and Robert Simmon.

Everyone notices when a fault ruptures quickly — the ground shakes and shudders, and sometimes, the seas churn. However, tectonic plates can also creep past each other so slowly that it’s almost imperceptible. Researchers say they’ve now identified the longest example to date of this type of movement along the Japan Trench in the decade leading up to the devastating magnitude-9.0 earthquake that shook the island of Honshu in 2011.

Yosemite's cliffs in retreat

Mon, 20 Apr 2015 10:38:20 -0400

This past winter, two athletes grabbed the world’s attention as they climbed up the sheer walls of Yosemite National Park’s El Capitan. But some geologists are more concerned with what falls down these precipitous faces — namely, rocks. Park geologist Greg Stock has developed a history of rockfalls in Yosemite valley dating back 15,000 years, which reveals how its cliffs have crumbled since glaciers disappeared at the end of the last ice age.

Comet water unlike Earth's

Mon, 20 Apr 2015 10:26:32 -0400

Comet 67P as seen by the Rosetta spacecraft on Aug. 7, 2014. Credit: European Space Agency.

Scientists have long suspected that much of the water that fills our planet’s oceans may have come from asteroids or comets that collided with the early Earth. Now, recently reported data from the European Space Agency’s Rosetta mission, which landed its Philae probe on comet 67P/Churyumov-Gerasimenko in November, appears to favor an asteroid origin story for Earth’s water.

Could U.S. phosphate deposits help meet growing rare earth demand?

Mon, 20 Apr 2015 10:17:00 -0400

Phosphorite rocks in a number of U.S. localities were found to contain high levels of valuable rare earth elements. Credit: Ryan Shell, GFDL.

The modern world runs on rare earth metals — they are essential ingredients in light bulbs, smartphones, wind turbines and military weapons, among other uses. Currently, China supplies more than 95 percent of the global demand for rare earth elements (REEs), giving it a virtual monopoly. But new research suggests that the United States may contain vast domestic reserves of its own that could dwarf known deposits.

Mysterious rapid radio burst captured live

Mon, 20 Apr 2015 09:07:08 -0400

In addition to the Parkes telescope, the Australia Telescope Compact Array turned to look for evidence of the fast radio burst. Credit: ©John Masterson/CSIRO, CC BY 3.0.

Last year, astronomers received a signal from the depths of the cosmos: a fleeting pulse of intense electromagnetic radiation known as a fast radio burst (or FRB). First discovered in 2007, these millisecond blasts occur sporadically and continue to baffle astronomers. Now, for the first time, an FRB has been caught red-handed.

Earliest primates were tree dwellers

Mon, 20 Apr 2015 09:02:41 -0400

The ankle bones of the 65-million- year-old primate Purgatorius, shown here in an artist's rendition, reveal that the earliest primates likely lived in trees. Credit: Patrick Lynch/Yale University.

The first primates evolved shortly after the mass extinction of the dinosaurs about 66 million years ago. But whether these small mammals lived on the ground or in trees has puzzled paleontologists, who only had fossil teeth and jaws to examine, which left much of the animals’ appearance and behavior a mystery.

Geologic Column: The Rumpelstiltskin Factor

Thu, 16 Apr 2015 13:14:42 -0400

Credit: Public Domain.

The title above may sound like one of those Robert Ludlum novels that works better as a movie than it does in the author’s long-winded prose. But my intention is to emphasize the importance of names, an importance children often first learn about from fairy tales or folklore. In one of the “Children’s and Household Tales” collected by the Brothers Grimm in 19th-century Germany, Rumpelstiltskin is a dwarf whose magical abilities spring from his secret name. For the price of her first-born child, he helps a girl fool a king into thinking that she can spin straw into gold and thereby solve His Majesty’s major cash-flow problem. Rumpelstiltskin does the spinning and the grateful king makes the girl his queen. Demanding his reward, the dwarf reappears when the queen gives birth. She pleads for mercy; the dwarf relents and gives her three days to guess his name before she loses the child. If he had had a common name like Jim or Fred or even Gunter, the task would have been hard enough, but his name is an outlier among monikers. Yet, by subterfuge she discovers the answer in time, and the dwarf storms off, madder than Yosemite Sam after his cigar explodes.

Comment: When scientists come under legal attack

Thu, 16 Apr 2015 12:59:04 -0400

A fundamental tenet of science is that the search for knowledge is objective. Unfortunately, this principle has been turned on its head in recent years by politically motivated groups when scientific findings endanger their ideologies or business interests. To distract from and discredit such findings, these groups have launched legal challenges and other attacks against a small but growing number of scientists, who must then legally defend their work, correspondence and public statements.

Bird genomes untangle branches of avian family tree

Tue, 07 Apr 2015 13:24:30 -0400

Birds are one of the most diverse groups of vertebrates on Earth, with more than 10,000 known species. Credit: ©Shutterstock.com/Tom Reichner.

Birds, the only surviving descendants of dinosaurs, have one of the most fascinating — and perplexing — family trees in the animal kingdom. To sort it out, an international collaboration known as the Avian Phylogenomics Project has sequenced the genomes of dozens of different bird species, representing all the orders in the bird family. Even with a glut of new data, however, many questions remain about the branches of the avian family tree.

Benchmarks: May 8, 1902: The deadly eruption of Mount Pelée

Tue, 07 Apr 2015 11:47:37 -0400

The volcanic eruption of Mount Pelée on Martinique in 1902. Credit: Library of Congress.

At the turn of the 20th century, the town of St. Pierre was known as the “Paris of the Caribbean.” Nestled into the northwest coast of the French island of Martinique, it boasted a bustling harbor where ships hauled away precious loads of sugar and rum, and it had usurped the official capital — Fort-de-France — as the colony’s cultural center. But St. Pierre had a problem: it lay in the shadow of a massive volcano.

Down the Earth With: Clive Oppenheimer

Tue, 07 Apr 2015 11:34:54 -0400

Volcanologist Clive Oppenheimer. Credit: courtesy of Clive Oppenheimer.

North Korea is perhaps the most isolated country in the world, with a people, culture and landscape largely veiled from outside observation, which rarely hosts few Westerners. However, in recent years a smattering of western scientists have visited the country, including volcanologist Clive Oppenheimer from the University of Cambridge in England. In 2011, Oppenheimer was invited by North Korean scientists who were concerned about a sleeping giant of a volcano on the northern border with China that had shown signs of restlessness. A few weeks later, he found himself on the imposing but beautiful mountain, known as Paektu-san to the Koreans (or Changbaishan in China), with a small team trying to unravel the volcano’s past and potential future activity. He has returned to North Korea twice since, and is looking to extend the rare collaboration further.

Geomedia: Books: Breaking New Ground

Tue, 07 Apr 2015 11:28:29 -0400

"Breaking New Ground: A Personal History," by Lester R. Brown, W. W. Norton & Co., 2013, ISBN 978-0393240061.

Agricultural scientist Lester Brown ponders the global future of agriculture, but his roots as a tomato farmer make him keenly aware of the local challenges of feeding a growing population. A 1986 recipient of a MacArthur Fellowship for his pioneering interdisciplinary work in the field of sustainable development, and the founder of the Worldwatch Institute, Brown reflects on his life and career in his autobiography, “Breaking New Ground: A Personal History.”

On-site inspections

Tue, 07 Apr 2015 11:12:43 -0400

rained volunteer inspectors measure subsurface electrical conductivity during the CTBTO's 2014 integrated field exercise in Jordan. Credit: ©CTBTO Preparatory Commission, CC BY 2.0.

Portable laboratories and equipment made up the operations base for IFE14. Credit: ©CTBTO Preparatory Commission, CC BY 2.0.

In the event that the CTBT enters into force, a third element of the CTBTO’s verification regime — in addition to the IMS and IDC — would come into play: on-site inspections (OSI). Given potential evidence of a nuclear test, member states can call for an inspection of the suspected area as a final verification measure.

Beyond the bomb: The world's nuclear watchdog expands its science

Tue, 07 Apr 2015 10:32:14 -0400

The underwater nuclear weapons test dubbed

So much of science these days is about connections and multitasking. And nowhere is this more true perhaps than with the widespread instrument networks that keep watch for the often faint sounds of impending danger, whether natural or human-made.

Getting there and getting around Nepal

Fri, 03 Apr 2015 13:26:25 -0400

A street vendor in Kathmandu selling colorful powders used in Hindu festivals, such as Diwali. Credit: Jesse Davenport.

A Nepali woman cleaning and sorting rice. Credit: Jesse Davenport.

Flights: The only international airport in Nepal is Tribhuvan International Airport in Kathmandu. There are a handful of other airports throughout Nepal, but these are much smaller and offer only domestic flights. There are a few direct flights from the U.S., but these are quite expensive. Most itineraries require at least one stop, for example, in the Middle East, such as in Qatar or Abu Dhabi, or in China or Thailand. Many flight options also offer layovers in India, although Indian itineraries require a transit visa that must be procured before traveling.

Of temperature and tone: Has climate shaped human languages?

Fri, 03 Apr 2015 13:16:43 -0400

The global distribution of tonal (blue dots) versus nontonal (orange dots) modern languages as identified in a new study. Credit: K. Cantner, AGI, after Everett et al., PNAS, 2015.

Humans today speak more than 6,500 languages, and thousands more dialects once spoken have gone extinct. Understanding how and why so many languages have evolved over human history has long been the work of linguists. Recently, however, the emerging field of geo-phonetics has begun looking into how geography — and perhaps climate — affects language. In a new study, researchers suggest that humidity and temperature, which can impact our ability to craft certain sounds, appear to have influenced the evolution of tonality in languages in different parts of the world.

Travels in Geology: A trek through Himalayan geology in Nepal

Fri, 03 Apr 2015 12:41:43 -0400

Near the Annapurna Base Camp in Nepal. Credit: Julia Rosen.

[Editor’s Note: On April 25, 2015, a magnitude-7.8 earthquake struck 80 kilometers northwest of Kathmandu, Nepal, killing and injuring thousands and devastating many of the areas written about earlier in this Travels in Geology feature. The disaster prompted the U.S. State Department to issue a Nepal Travel Alert that will remain in effect until Aug. 1, 2015.]

Fire-driven clouds and swirling winds whipped up record-setting New Mexico blaze

Fri, 03 Apr 2015 12:32:02 -0400

When it struck, the 2011 Las Conchas Fire was the largest wildfire in New Mexico's history. Credit: Kari Greer/U.S. Forest Service.

At about 1 p.m. on June 26, 2011, a wind-downed power line sparked a blaze in the Las Conchas area of Santa Fe National Forest. It would become the largest fire in New Mexico’s history at the time. Within hours, the flames spread to cover more than 160 square kilometers, threatening the town of Los Alamos, home of Los Alamos National Laboratory (LANL), which develops nuclear fuels and safeguards nuclear weapons, among other activities. Now, a new study identifies why the fire spread so far so fast, and the results may have implications for fire management practices in other mountainous regions.

Ground-shaking research: How humans trigger earthquakes

Fri, 03 Apr 2015 11:03:06 -0400

A number of earthquakes occurred during the 1930s while Lake Mead was being impounded behind Hoover Dam (shown here in May 1935), including a magnitude-5 event in 1939. Filling reservoirs is one of the ways humans can trigger earthquakes. Credit: U.S. Bureau of Reclamation.awes

In the pre-dawn hours of Aug. 6, 2007, six miners were laboring 450 meters underground, excavating coal from the Crandall Canyon Mine in the mountainous terrain of central Utah’s Wasatch Plateau. Suddenly, pillars supporting the mine roof ruptured, causing a major collapse over an area of 200,000 square meters and trapping the men underground.

May 2015 on EARTH Magazine

Energy Notes: October 2013-2014

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

Mineral Resource of the Month: Graphite

Counting 'tree' rings in fish skulls provides climate clues

California's big trees dying of thirst

Geomedia: On the web: Personalizing drought data with digital tools

Megafloods mostly shaped Icelandic canyon landscape

Pre-settlement erosion rates illuminated

Energy Notes: November 2013-2014

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

Mineral Resource of the Month: Iron oxide pigments

Comment: The new frontier: Homesteading on Mars

Down to Earth With: Marine Geophysicist Maya Tolstoy

Geologic Column: On the Summer Solstice

Getting there and getting around in South Australia

Travels in Geology: Glaciers and grapes in South Australia

Comparing apples to oranges, hyenas to humans

The new anthropology: From bones and stones to biology and behavior

And best picture goes to...'Dante's Peak'

Rock stars: Geologists on the silver screen

Flames fan lasting fallout from Chernobyl

Amber-encased plant could be oldest known grass: Specimen may also preserve a Cretaceous-aged hallucinogen

Where on Earth? - May 2015

Clues for May 2015:

Red Planet Roundup: May 2015

Ancient moss reveals tsunami timing

More warming may mean more lightning

A decade of slow slip may have preceded Japan's 2011 earthquake

Yosemite's cliffs in retreat

Comet water unlike Earth's

Could U.S. phosphate deposits help meet growing rare earth demand?

Mysterious rapid radio burst captured live

Earliest primates were tree dwellers

Geologic Column: The Rumpelstiltskin Factor

Comment: When scientists come under legal attack

Bird genomes untangle branches of avian family tree

Benchmarks: May 8, 1902: The deadly eruption of Mount Pelée

Down the Earth With: Clive Oppenheimer

Geomedia: Books: Breaking New Ground

On-site inspections

Beyond the bomb: The world's nuclear watchdog expands its science

Getting there and getting around Nepal

Of temperature and tone: Has climate shaped human languages?

Travels in Geology: A trek through Himalayan geology in Nepal

Fire-driven clouds and swirling winds whipped up record-setting New Mexico blaze

Ground-shaking research: How humans trigger earthquakes

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