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natural hazards

Hazard lingers after South Napa earthquake

The magnitude-6 earthquake that shook buildings and rattled wineries in California’s Napa Valley on Aug. 24, 2014, continues to affect homes in at least one neighborhood in the city of Napa more than three months later. The quake’s epicenter was about 6 kilometers south of the city, but post-quake movement, or afterslip, along the principal fault line to the north of the epicenter is ongoing, according to a fast-track report prepared by the U.S. Geological Survey (USGS) for the Federal Emergency Management Agency. Scientists involved in producing the 51-page report — released to the public on Tuesday — discussed it at a press conference at the annual meeting of the American Geophysical Union in San Francisco.

17 Dec 2014

Colorado River Basin sees severe groundwater depletion

Over the past 14 years, the Colorado River Basin has experienced its worst drought since precipitation records have been kept, starting in the 1960s. The basin supplies water used for agriculture and in households in seven states, affecting more than 40 million people. In a study recently published in Geophysical Research Letters, researchers have found that the reservoirs that store water in the basin are at record low levels. What’s more, the research shows that in addition to shrinking reservoirs, groundwater is being depleted much faster than previously thought, which could have major implications for the region’s future water security.

24 Sep 2014

Human-induced earthquakes shake less

Occurrences of earthquakes in the Central and Eastern United States have increased since 2009 — a phenomenon that many scientists attribute to the growing use of hydraulic fracturing for fossil fuel extraction. Most agree that it’s not the fracturing itself, but the reinjection of wastewater into wells for containment beneath the surface that tends to induce seismic activity. Now, new research looking at the effects of induced seismic activity suggests that human-made earthquakes and naturally occurring tectonic earthquakes are felt differently at the surface.

21 Aug 2014

Oso landslide report yields some answers

Early on March 22, 2014, the most damaging landslide in U.S. history devastated the community of Oso, Washington. Forty-three people perished, most inside their homes, when a saturated hillside nearby gave way and a massive mudflow swept over their neighborhood. On July 22, a search crew recovered the last of the 43 bodies, exactly four months after the landslide, and coincidentally on the same day, a team of scientists and engineers released an exhaustive report detailing the event and its implications.

01 Aug 2014

Shifting winds blow away Taupo's 'Ultraplinian' title

The eruption of New Zealand’s Taupo volcano about 1,800 years ago is the stuff of legends. With an ash plume estimated to have reached an astounding height of 50 kilometers — substantially higher than any other known eruption — Taupo was once thought to justify its own volcanic explosivity category: Ultraplinian. But new research looking at the effects of changing wind patterns on the eruptive deposits left by Taupo may lead scientists to downgrade the event to Plinian, effectively making the term Ultraplinian obsolete.
 

01 Jul 2014

Longmenshan fault zone in the spotlight after two major quakes in five years

In May 2008, a magnitude-7.9 earthquake struck near Wenchuan, China, killing more than 80,000 people in the country’s biggest quake since 1950. Then, in April 2013, the magnitude-6.6 Lushan earthquake hit just 90 kilometers to the south — also within China’s Longmenshan Fault Zone, which separates the Tibetan Plateau to the west from the Sichuan Basin to the east — and caused another 200 deaths. Now, scientists have found that a roughly 60-kilometer segment of the fault zone between the epicenters of the two big temblors could be the next to rupture, although no one knows when or how big it might be.

05 Jun 2014

Comment: Preparing for the death of Earth

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.

22 May 2014

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

At a few select facilites around the world, engineers are able to shake full-size buildings to learn how to make them safer during earthquakes. Take a look at the massive shake tables that make it possible.

23 Apr 2014

Resolving a misplaced source of volcanism in the Galapagos

Geological models have long suggested the mantle plume that built the Galápagos islands lies below Fernandina Island. Using a novel combination of seismic techniques, however, scientists have found a mantle anomaly that appears to be the Galápagos plume located 150 kilometers southeast of Fernandina Island. The new findings better explain the ongoing volcanic activity and also shed light on interactions between the mantle and crust, researchers say.

07 Apr 2014

Volcanic lightning generated in a bottle

Scientists know very little about how lightning is generated by volcanic eruptions, in large part because of the danger and difficulty in monitoring the phenomenon in the field. But a new apparatus for generating volcanic lightning in the lab may shed light on the subject.

06 Apr 2014

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