Tag Archives: crust

New Imaging Technique Uses Earth’s Warped Surface to Reveal Rocky Interior

Surface mapping technology such as GPS, radar and laser scanning have long been used to measure features on the Earth’s surface. Now, a new computational technique developed at The University of Texas at Austin is allowing scientists to use those technologies to look inside the planet. (more…)

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Eight Seconds of Terror

A JPL Scientist Reflects on L.A.’s Last Big Quake

Twenty years ago this week, in the predawn darkness of Jan. 17, 1994, at five seconds before 4:31 a.m. PST, the ground ruptured violently on a blind thrust fault (a crack in Earth’s crust that does not reach the surface) about 11 miles (18 kilometers) beneath Reseda, in California’s San Fernando Valley about 20 miles (31 kilometers) northwest of downtown Los Angeles. The resulting magnitude 6.7 earthquake, known as the Northridge earthquake, became the first large quake to strike directly under an urban area in the United States since the 1933 magnitude 6.4 earthquake in Long Beach, Calif. (more…)

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Lunar impacts created seas of molten rock

A new analysis of data from NASA’s Lunar Orbiter Laser Altimeter (LOLA) shows that molten rock may have been present on the Moon more recently and for longer periods than previously thought. Differentiation — a settling out of rock layers as liquid rock cools — would require thousands of years and a fluid rock sea at least six miles deep.

PROVIDENCE, R.I. [Brown University] — Early in the Moon’s history an ocean of molten rock covered its entire surface. As that lunar magma ocean cooled over millions of years, it differentiated to form the Moon’s crust and mantle. But according to a new analysis by planetary scientists from Brown University, this wasn’t the last time the Moon’s surface was melted on a massive scale. (more…)

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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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Clean Energy From CO2?

Global warming villain CO2 may have a surprisingly green future

The next frontier in the search for renewable energy lies less than two miles from where you are now.

Unless you’re reading this on the International Space Station.

Geothermal heat a mile or two deep in Earth’s crust is a potential source of energy that could be tapped by an unlikely carrier: carbon dioxide (CO2), the central villain in global warming. That energy, unlike solar and wind, could be easily turned on and off without the intermediate step of being stored in a battery. And it would be constant and reliable. (more…)

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New Understanding of Earth’s Mantle Beneath The Pacific Ocean

Washington, D.C. — Scientists have long speculated about why there is a large change in the strength of rocks that lie at the boundary between two layers immediately under Earth’s crust: the lithosphere and underlying asthenosphere. Understanding this boundary is central to our knowledge of plate tectonics and thus the formation and evolution of our planet as we know it today. A new technique for observing this transition, particularly in the portion of Earth’s mantle that lies beneath the Pacific Ocean basin, has led Carnegie and NASA Goddard scientist Nick Schmerr to new insight on the origins of the lithosphere and asthenosphere. His work is published March 23 in Science.

The lithosphere-asthenosphere boundary, or LAB, represents the transition from hot, convecting mantle asthenosphere to overlying cold and rigid lithosphere. The oceanic lithosphere thickens as it cools over time, and eventually sinks back into the mantle at Earth’s so-called subduction zones. (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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NASA Twin Spacecraft on Final Approach for Moon Orbit

PASADENA, Calif. — NASA’s twin spacecraft to study the moon from crust to core are nearing their New Year’s Eve and New Year’s Day main-engine burns to place the duo in lunar orbit.

Named Gravity Recovery And Interior Laboratory (GRAIL), the spacecraft are scheduled to be placed in orbit beginning at 1:21 p.m. PST (4:21 p.m. EST) for GRAIL-A on Dec. 31, and 2:05 p.m. PST (5:05 p.m. EST) for GRAIL-B the next day. (more…)

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