Phase transitions in olivine may be the cause of a deep seismic fault

Left: the retrieved sample. The red police lines represent errors. Center: The rift is filled with nanocrystalline olives and wadslite. Right: Close-up view of the error in error. The iron-rich particles (product of partial fusion of olive: green) are distributed along the grain boundaries of the nanocrystalline peridot. Credit: Tomohiro Ohuchi, Ehime University

Earthquakes that occur hundreds of kilometers deep in the mantle are called “deep focus earthquakes”. Such earthquakes sometimes lead to serious disasters such as the 1994 Bolivia earthquake, which occurred at a depth of 638 km with a magnitude of 8.3.

However, the cause of high-focal earthquakes has been a mystery, because earthquakes occur with rapid fault slip, which is difficult under large deep mantle stresses. Attempts have been made to understand the mechanism of occurrence of hyperfocal earthquakes based on laboratory deformation experiments, but experiments under deep mantle conditions have not been performed due to technological limitations.

The team, for the first time, performed deformation experiments on natural olivine, the main mineral in the mantle and oceanic lithosphere (slate), by means of a modern, large-scale deformation apparatus in combination with a synchrotron. X-ray notes. They observed significant abnormalities in the sample by X-ray imaging under deep mantle conditions and ‘seismicity’ associated with ultrasonic acoustic emission measurements.

After careful analyzes of the retrieved sample, they found that the cause of the crack was the growth of “new” olivine with ultrafine grains of tens of nanometers at the phase transformation of the “old” olive, which acted as a lubricant for the rapid slip of the fault. They also found evidence that the sample melted locally along the fault due to the very high temperature generated by the rapid slip. Their model, based on these laboratory experiments, explains the distribution of deep-focus earthquakes, which increases with depths from ~400 km to ~600 km, where metastatic “old” olivine is expected to form “new” ultrafine grains. olivine.

The research has been published in the journal Nature Communications.

Left: Forming lenticular bundles filled with nanocrystalline peridot/Wadslite. Right: localization of the shear on the weak layer formed by the fusion of lenticular bundles. This results in shear heating followed by deeply focused faulting earthquakes. Credit: Tomohiro Ohuchi, Ehime University This study indicates that highly concentrated earthquakes are preferentially distributed around the surface of the spreading olefin wedge, which forms the central portion of the sliding plate. Credit: Tomohiro Ohuchi, University of Ehime’s Possible Olivine Mechanism for Boron Transfer to the Earth’s Deep Mantle More information: Tomohiro Ohuchi et al, In situ X-ray and acoustic observations of deep seismic fault on phase transitions in olivine, Nature Communications (2022). DOI: 10.1038 / s41467-022-32923-8

Presented by Ehime University

Quote: Phase transitions in olivine may cause deep seismic fault (2022, Sep 16) Retrieved on Sep 17, 2022 from https://phys.org/news/2022-09-phase-transitions-olivine-deep- seismic.html

This document is subject to copyright. Notwithstanding any fair dealing for the purpose of private study or research, no part may be reproduced without written permission. The content is provided for informational purposes only.

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