Scientists Detect Surprise Structures Wrapped Around Earth’s Core

Blobs of hot, dense material that curl around Earth’s core are much more widespread than previous research suggests.

A new method of analysing earthquake data has found even more of the previously detected continent-sized zones at the boundary between the planet’s core and mantle.

 

We still don’t know what these blobs are – they could be magma, molten iron leaking from the core, or something else –  but with a more complete, detailed map of where they are, we can better understand the geological processes occurring deep inside Earth’s interior.

The core boundary lies some 2,900 kilometres (1,800 miles) below Earth’s surface. That’s extremely out of reach, so if we want to know what conditions are like down there, we have to get creative. Luckily, Earth comes with a built-in tool for probing its own guts: earthquakes.

The way quakes and tremors propagate through different kinds of material inside the planet has allowed seismologists to reconstruct and map the composition of Earth’s interior.

This is how vast blobs of super-hot material were identified at the core-mantle boundary, decades ago.

Because the heat causes greater degrees of melting, these zones slow velocity of the earthquake waves right down, so they’re known as ultra low velocity zones.

But earthquakes can be an unsatisfactory tool, providing only trickles of information at a time. You have to wait for earthquakes; each earthquake only probes a narrow zone; and weaker signals can get lost in the broader noise.

 

To compensate for this problem, researchers from the University of Maryland, Johns Hopkins University, and Tel Aviv University turned to an unusual source: the stars.

Well, not actually the star – an algorithm for studying the stars. It’s called the Sequencer, and it’s designed to run through large astronomical datasets looking for patterns.

As it turns out, this algorithm can be tweaked to look at seismic data, too. A lot of seismic data.

The researchers fed it 30 years of data – around 7,000 seismograms of one particular type of seismic wave – looking for the seismic echoes indicating an ultra-low velocity zone that we may have missed in previous analyses. And bingo, they got a hit.

“By looking at thousands of core-mantle boundary echoes at once, instead of focusing on a few at a time, as is usually done, we have gotten a totally new perspective,” said geologist Doyeon Kim of the University of Maryland.

“This is showing us that the core-mantle boundary region has lots of structures that can produce these echoes, and that was something we didn’t realise before because we only had a narrow view.”

The results returned by the Sequencer revealed subtle changes in seismic waveforms from earthquakes in Asia and Oceania, suggesting a previously undetected ultra low velocity zone beneath the Marquesas Islands in the South Pacific.

(Doyeon Kim/University of Maryland)

“We were surprised to find such a big feature beneath the Marquesas Islands that we didn’t even know existed before,” said geologist Vedran Lekić of the University of Maryland.

“This is really exciting, because it shows how the Sequencer algorithm can help us to contextualise seismogram data across the globe in a way we couldn’t before.”

 

In addition, the known ultra low velocity zone beneath Hawaii produced seismic echoes much louder than expected. This suggests that it is significantly larger than previous studies had estimated.

And the overall findings suggest that Earth’s guts are rather more blobby than we suspected.

“We found echoes on about 40 percent of all seismic wave paths,” Lekić said.

“That was surprising because we were expecting them to be more rare, and what that means is the anomalous structures at the core-mantle boundary are much more widespread than previously thought.”

Having demonstrated the Sequencer’s efficacy on one type of wave, the team’s techniques can now be applied to other types of waves and frequencies. This could help compile a new, high-resolution map of the Earth’s interior.

In turn, the physical properties this reveals could help geologists infer the chemistry and temperature of the structures, leading us closer to solving the mystery of what’s causing these strange, dense zones wrapped around the heart of Earth.

The research has been published in Science.

 

.

What Are The Main Benefits Of Comparing Car Insurance Quotes Online

LOS ANGELES, CA / ACCESSWIRE / June 24, 2020, / Compare-autoinsurance.Org has launched a new blog post that presents the main benefits of comparing multiple car insurance quotes. For more info and free online quotes, please visit https://compare-autoinsurance.Org/the-advantages-of-comparing-prices-with-car-insurance-quotes-online/ The modern society has numerous technological advantages. One important advantage is the speed at which information is sent and received. With the help of the internet, the shopping habits of many persons have drastically changed. The car insurance industry hasn't remained untouched by these changes. On the internet, drivers can compare insurance prices and find out which sellers have the best offers. View photos The advantages of comparing online car insurance quotes are the following: Online quotes can be obtained from anywhere and at any time. Unlike physical insurance agencies, websites don't have a specific schedule and they are available at any time. Drivers that have busy working schedules, can compare quotes from anywhere and at any time, even at midnight. Multiple choices. Almost all insurance providers, no matter if they are well-known brands or just local insurers, have an online presence. Online quotes will allow policyholders the chance to discover multiple insurance companies and check their prices. Drivers are no longer required to get quotes from just a few known insurance companies. Also, local and regional insurers can provide lower insurance rates for the same services. Accurate insurance estimates. Online quotes can only be accurate if the customers provide accurate and real info about their car models and driving history. Lying about past driving incidents can make the price estimates to be lower, but when dealing with an insurance company lying to them is useless. Usually, insurance companies will do research about a potential customer before granting him coverage. Online quotes can be sorted easily. Although drivers are recommended to not choose a policy just based on its price, drivers can easily sort quotes by insurance price. Using brokerage websites will allow drivers to get quotes from multiple insurers, thus making the comparison faster and easier. For additional info, money-saving tips, and free car insurance quotes, visit https://compare-autoinsurance.Org/ Compare-autoinsurance.Org is an online provider of life, home, health, and auto insurance quotes. This website is unique because it does not simply stick to one kind of insurance provider, but brings the clients the best deals from many different online insurance carriers. In this way, clients have access to offers from multiple carriers all in one place: this website. On this site, customers have access to quotes for insurance plans from various agencies, such as local or nationwide agencies, brand names insurance companies, etc. "Online quotes can easily help drivers obtain better car insurance deals. All they have to do is to complete an online form with accurate and real info, then compare prices", said Russell Rabichev, Marketing Director of Internet Marketing Company. CONTACT: Company Name: Internet Marketing CompanyPerson for contact Name: Gurgu CPhone Number: (818) 359-3898Email: [email protected]: https://compare-autoinsurance.Org/ SOURCE: Compare-autoinsurance.Org View source version on accesswire.Com:https://www.Accesswire.Com/595055/What-Are-The-Main-Benefits-Of-Comparing-Car-Insurance-Quotes-Online View photos

Picture Credit!