Tag Archives: seismic wave

Magma in Earth’s Mantle Forms Deeper Than Once Thought

Study simulating pressures in mantle beneath the ocean floor shows that rocks can melt at depths up to 250 kilometers

Magma forms far deeper than geologists previously thought, according to new research results.

A team led by geologist Rajdeep Dasgupta of Rice University put very small samples of peridotite, rock derived from Earth’s mantle, under high pressures in a laboratory.

The scientists found that the rock can and does liquify, at least in small amounts, at pressures equivalent to those found as deep as 250 kilometers down in the mantle beneath the ocean floor. (more…)

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Within the Earth, Blobs of Molten Iron on the Move

New research by Yale University scientists suggests an explanation for the amount of iron in the Earth’s largest interior layer, the mantle: migrating “iron-rich blobs” generated by chemical interactions in the zone between the planet’s core and mantle.

Scientists have long known of the core’s rich iron content, but they have struggled to explain how the rocky mantle acquires iron in any abundance. The newly reported iron-enrichment process could also explain how other elements, such as platinum and hydrogen, get into the mantle, researchers said — attached to the iron. (more…)

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3-D Laser Map Shows Earthquake Zone Before and After

*Geologists learn how earthquakes change the landscape — down to a few inches*

Geologists have a new tool to study how earthquakes change the landscape–down to a few inches. It’s giving scientists insights into how earthquake faults behave.

In this week’s issue of the journal Science, a team of scientists from the United States, Mexico and China reports the most comprehensive before-and-after picture yet of an earthquake zone, using data from the magnitude 7.2 event that struck near Mexicali, Mexico, in April 2010. (more…)

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No Evidence for Large Triggered Earthquakes Across the Globe

MENLO PARK, Calif. — New scientific research concludes that large earthquakes do not increase the global seismic hazard for more damaging earthquakes far from the mainshock. Although large aftershocks close to the mainshock remain highly probable following an earthquake, and small earthquakes less than magnitude 5 can be triggered at great distances, scientists at the U.S. Geological Survey and the University of Texas at El Paso found no significant increase in the rate of large earthquakes happening farther away than two to three times the length of the ruptured fault that caused the mainshock.  (more…)

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