Scientists detect unexpected widespread structures near Earth's core

Phys.org ^ | 06/11/2020 | University of Maryland

[BenLurkin]

Earthquakes generate seismic waves below Earth's surface that travel thousands of miles. When the waves encounter changes in rock density, temperature or composition, they change speed, bend or scatter, producing echoes that can be detected. Echoes from nearby structures arrive more quickly, while those from larger structures are louder. By measuring the travel time and amplitude of these echoes as they arrive at seismometers in different locations, scientists can develop models of the physical properties of rock hidden below the surface. This process is similar to the way bats echolocate to map their environment

Using a machine learning algorithm called Sequencer, the researchers analyzed 7,000 seismograms from hundreds of earthquakes of 6.5 magnitude and greater occurring around the Pacific Ocean basin from 1990 to 2018. Sequencer was developed by the new study's co-authors from Johns Hopkins University and Tel Aviv University to find patterns in radiation from distant stars and galaxies. When applied to seismograms from earthquakes, the algorithm discovered a large number of shear wave echoes.

The study revealed a few surprises in the structure of the core-mantle boundary.

The scientists found that the large patch of very dense, hot material at the core-mantle boundary beneath Hawaii produced uniquely loud echoes, indicating that it is even larger than previous estimates. Known as ultralow-velocity zones (ULVZs), such patches are found at the roots of volcanic plumes, where hot rock rises from the core-mantle boundary region to produce volcanic islands. The ULVZ beneath Hawaii is the largest known.

This study also found a previously unknown ULVZ beneath the Marquesas Islands.

[the_daug]

“This study also found a previously unknown ULVZ beneath the Marquesas Islands.”

Got out of town on a boat goin’ to Southern islands
Sailing a reach before a followin’ sea
She was makin’ for the trades on the outside
And the downhill run to Papeete Off the wind on this heading lie the Marquesas
We got 80 feet of the waterline nicely making way
In a noisy bar in Avalon I tried to call you
But on a midnight watch I realized why twice you ran away

[SunkenCiv]

Thanks BenLurkin.

[SunkenCiv]

See also the Potsdam Gravity Potato keyword.

join or quit view topics view or post blog bookmark post new topic subscribe

[Bubba Ho-Tep]

I have a copy of that book.

So do I. Picked it up at a flea market back in the late 1970s. Kind of a pricy item these days. The best part is the ads for other books by that publisher in the back.

[smvoice]

I think I will reread Dante’s Inferno

[PLMerite]

My aunt gave me her copy about 50 years ago. I have a lot of weird books now.

[doorgunner69]

Those damn echoes are ruining my sleep.

Been wondering for a long time why I could not sleep the whole night.

[HandyDandy]

Is such a thing even possible?

[Ruy Dias de Bivar]

The lost continent of MU, LeMUria. At the Earth’s Core. So was Edgar Rice Burroghs right or not, or was it Churchward.

[faucetman]

Call Rick and Marty Lagina!

[colorado tanker]

There is another portal to Inner Earth under Denver International Airport.

[\/\/ayne]

[SunkenCiv]

The rest of the Potsdam Gravity Potato keyword, chrono:

• Search for MH370 Revealed Ocean Crust Waves [2020]
• Rapid Drift of Magnetic North Explained [2020]
• Something Strange Sends Tech Haywire at Earth's Poles, And NASA Wants to Know More [2019]
• How Earth's mantle is like a Jackson Pollock painting [2019]
• The Nippon Foundation-GEBCO Seabed 2030 Project [2018]
• Scientists model Mercury's glaciers [2018]
• Earth's Second Magnetic Field: Satellite Image Reveals Invisible Force From Ocean Currents [2018]
• US Navy locates crashed plane deep on Pacific seabed [2018]
• New Seafloor Map Reveals How Strange the Gulf of Mexico Is [2017]
• The Search for MH370 Revealed Secrets of the Deep Ocean [2017]
• Scientists find 500 U.S. seabed vents of powerful greenhouse gas [2016]
• Vast asteroid created 'Man in Moon's eye' crater [2016]
• Seabed Scanning for East Anglian windfarm reveals Uncharted WWI German Submarine [2016]
• Ocean Search for Malaysian Airliner Finds 2nd Shipwreck [MH370] [2016]
• Seabed Gives Up Spanish Armada Wreck Cannons [2015]
• MH370 search discovers a shipwreck not the missing plane [2015]
• Astronomy Picture of the Day -- Gravitational Anomalies of Mercury [2015]
• Inconvenient study: Methane seepage from the Arctic seabed has been occurring for millions of years [2015]
• Seafloor volcano pulses may alter climate: [2015]
• AirAsia QZ8501: Plane tail lifted from seabed [2015]
• Astronomy Picture of the Day -- The Potsdam Gravity Potato [2014]
• Potato Earth: Gravity satellite reveals what our planet REALLY looks like [2011]
• The Moon reveals its weirder side - SELENE mission reports on gravity anomalies. [2009]
• Does a giant crater lie beneath the Antarctic ice? [2006]
• Exploring The Ocean Basins With Satellite Altimeter Data [2005]
• Gravity variations predict earthquake behavior [2003]
• 'Potato' Earth's Deep Secrets (Gravity Map) [2003]
• Astronomy Picture Of The Day : A Gravity Map of Earth [2001]