HAZARDS

hazards

Casting a seismic shadow

In the week or two before the magnitude-8.6 Indian Ocean earthquake in 2012, Earth was unusually quiet, with few large quakes over magnitude 5. Afterward, seismic activity all over the globe was elevated for more than a week. Then, suddenly, global seismicity dropped off precipitously: Beginning two weeks after the mainshock, no earthquakes of magnitude-6.5 or greater occurred for 95 days.

19 Oct 2014

Kilauea eruptions could shift from mild to wild

Hawaii’s Kilauea volcano is famously effusive: Low-viscosity lava oozes out of the main caldera and two active rift zones along the southern shore of the Big Island. But scientists suspect that Kilauea’s eruptions haven’t always been so mild, and a new study is providing further evidence supporting that notion. In the past 2,500 years, at least two cycles of explosive eruptions lasting several centuries each have rocked the island. The switch from effusive back to explosive is likely to occur again, scientists say, but probably not anytime soon.
 

14 Oct 2014

Benchmarks: October 9, 1963: The Vajont Landslide kills 2,500 in Italy

In 45 seconds, everything changed. What had been a towering mountainside collapsed into a pile of rubble; what had been a deep reservoir of placid water became a lethal flood; what had been a valley of small Italian villages was leveled to a barren outwash plain.

09 Oct 2014

Santiaguito Volcano's clockwork behavior provides an exceptional laboratory

If Earth breathes, Santiaguito Volcano in the Western Highlands of Guatemala could be its mouth. Roughly every half hour, like volcanic clockwork, Santiaguito’s active Caliente lava dome expands, filling with gas from depressurizing magma below. Then it exhales, often explosively, and deflates. Over the course of a day, you could almost keep time by it.

28 Sep 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

In Turkey, the older the fault, the bigger the quake: Good news for Istanbul?

For decades, Istanbul has been bracing for a major earthquake from the dangerously active North Anatolian Fault, which passes just 20 kilometers south of Turkey’s largest city. A new study looking at the age of the fault zone may set a cap on the maximum quake size that could hit Istanbul, suggesting that the older, more mature sections of the zone in the east are capable of bigger earthquakes than the younger sections in the west, which are near the city.
 

05 Sep 2014

Living in the shadow of Mauna Loa: A silent summit belies a volcano's forgotten fury

After 30 years, no one is quite sure when Hawaii’s Mauna Loa will erupt again. History warns us that the volcano’s current silence is anomalous, and the odds are good that it will reawaken within the next couple of decades. So geologists are already taking steps — upgrading their monitoring tools and talking with the public — to prepare for another eruption.

01 Sep 2014

Kilauea vs. Mauna Loa

In the 19th century, Mauna Loa was the most active volcano in the world. Today, Kilauea is the star. Tourism agencies, journalists, civil defense, and even U.S. Geological Survey Hawaiian Volcano Observatory (HVO) geologists have played a role in funneling public attention toward the Big Island’s youngest volcano. Consequently, some people ignore the other volcanic threats on the island, including Mauna Loa. Without knowing the differences between the two volcanoes, people walk away thinking that if they have seen and interacted with one, they know them all.

01 Sep 2014

How to keep the flows out: Build a wall

The upper northern slopes of Mauna Loa are a painter’s palette of red, brown and black lava rocks. A cluster of scientific buildings composing the Mauna Loa Observatory and Solar Observatory stands out with their reflective white and silver rooftops against the Mars-like backdrop.
 

01 Sep 2014

Infrasound reveals lava lake levels

The rises and falls of volcanic lava lakes are not easily tracked, especially when the lakes aren’t visible from crater rims. But recently, researchers found a way to monitor the lava lake at Chile’s Villarrica volcano using complementary methods to keep an eye on a feature they can’t always see.

22 Aug 2014

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