seismology4
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One Year Later – Return to the NoMelt Site
On December 18, 2012, the Research Vessel Melville departed San Diego to recover remainder of the NoMelt instruments and data. The expedition includes two scientists from Columbia’s Lamont-Doherty Earth Observatory: Post-doctoral scientist Patty Lin and graduate student Natalie Accardo. Natalie is sending regular reports from the ship.
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2010 Korea Bomb ‘Tests’ Probably False Alarms, Says Study
Amid Nuclear Tensions, a Seismic Reality Check
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Press-Ewing Seismograph on Jeopardy!
An important piece of earthquake-science history popped up a few weeks ago on Jeopardy!: “The Press-Ewing was an early seismograph, recording waves from these events. If you didn’t know a Press-Ewing from a French press, you were in luck. For $200, all you needed to know to formulate the question is what a seismograph measures.…
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Holidays on the High Seas
With round-the-clock shifts, there are precious opportunities for Santa to slip onto a research ship unseen. But slip in he did, leaving treats and gifts around the R.V. Langseth to brighten our day.
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Retrieving Instruments from the Deep
Over the first 22 days aboard the R/V Marcus G. Langseth, we’ve zigged and zagged our way over a 360×240 mile region of the Pacific plate, first dropping instruments to the seafloor, and then shooting airguns to them (see previous posts). The final step is to recover a subset of the instruments: 34 ocean-bottom seismometers…
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The Art of Sound in the Ocean
The NoMelt experiment aims to image the structure of an oceanic plate, including its deepest reaches up to 70 km beneath the seafloor. One of our primary means to do so is to create sound (acoustic) waves in the ocean from the ship, and record those waves at receivers on the seafloor, after they have…
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Deploying Instruments on the Seafloor in the Deep Ocean
Oceanic plates are born at mid-ocean ridges, where hot mantle rocks are brought very close to the surface, partially melt, and then cool and crystallize. The newly formed rocks move outwards from the mid-ocean ridge, making way for the next batch of hot rock rising from below. Inch by inch, over millions of years, oceanic…
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Rolling into Open Water in the Central Pacific
We nicknamed our project NoMelt because we seek to characterize a mature, pristine oceanic plate far from its volcanic origin at a Mid-Ocean Ridge, and away from areas of pronounced volcanism and melting that subsequently alter the structure of the plate. Our site in the central Pacific fits these scientific needs. However, one downside is…
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Probing an Oceanic Plate
Everything that we understand about the rhythms of the Earth’s surface – the slow growth of mountain chains, the creeping expansion of the ocean basins, the abrupt upheaval of a major earthquake, the explosive eruption of a volcano – is viewed through the context of plate tectonics. This simple yet highly successful model for describing…
