Shedding light on slow plate-slip tectonic movement in southwestern Japan – Eurasia Review

Within the next 30 years, the massive, devastating Nankai Troh earthquake is expected to hit southwestern Japan. Understanding the long-range slow-slide events (L-SSE (*1)) that occur along the plate interface between the Philippine Sea outflow plate and the Amur platen overflow under the Bungo Channel is essential for determining when such an earthquake occurred. To this end, Kobe University Professor Yoshika Shuichi (Urban Safety and Security Research Center) and SESHIMO Yukinari (First-Year Master’s Student, Department of Planetary Science, Graduate School of Science) analyzed the 2018-2019 Bungo Channel L-SSE using longitudinal GNSS data ( *2) Provided by the Geospatial Information Authority of Japan.

They reveal that while the 2018-2019 event was shorter than previous L-SSEs in this region, it was also larger in terms of slip amount and slip velocity, as well as seismic moments and torque magnitude. These and other findings from their findings provide further insight into the behavior of L-SSEs in the Bungo channel.

These results were published in the online journal “Scientific Reports” on January 10, 2022 at 10 AM GMT. This journal is published by the Nature Publishing Group (UK).

the main points

Illuminating the Bungo Channel slow-slip distribution is important for understanding the causal mechanism behind the Nankai Trough mega-earthquake, which is expected to occur in the near future.

This research group has highlighted the spatiotemporal distribution of the slow slip event that occurred in 2018-2019

Although occurring in the shortest time period, the 2018-2019 event was the highest recorded to date in terms of slip amount and slip velocity, as well as seismic moment (*3) and moment magnitude (*4) compared to past slow slip events in the Bungo Channel .

The 2018-2019 event is similar to the 2002-2004 slow slide in terms of starting location, coupon distribution, and order of subsidiary events.

Search background

In the Bungo Channel, located between Shikoku and Kyushu in southwestern Japan, the Philippine Sea plate descends in a northwesterly direction under the Amurian plate. Every 6 years or so, long-term slow slip events (L-SSE) frequently occur along the plate interface below this region. Each of these L-SSEs lasts anywhere from several months to two years.

The studies performed to date have analyzed the sliding distributions of L-SSEs that occurred in the following periods: 1996–1998, 2002–2004, and 2009–2011. It has been suggested that there is a possible relationship between these events and the occurrence of the Nankai Troh mega earthquake.

Illuminating the slip distributions of L-SSE in the Bungo channel is vital to understanding how such a massive earthquake occurs. Therefore, Kobe University researchers decided to conduct a new analysis of the L-SSE that occurred during the period 2018-2019.

Research Methodology and Results

Using longitudinal GNSS data, the researchers calculated the spatiotemporal distribution of the Bungo Channel L-SSE that occurred in 2018-2019. From the results, they understood that this event could be divided into two sub-events; The first sub-event ran from March to July 2018 (0.1 of the year = 36.5 days) and occurred under the southwest side of the Bungo Canal, and the second sub-event that occurred from August 2018 to April 2019 directly below the central part of the channel.

The 2018-2019 L-SSE lasted, for one year, for the shortest period of time compared to the previous Bungo Channel L-SSEs analyzed. Despite this, the L-SSE 2018-2019 was the largest event in terms of slip amount and slip velocity, as well as earthquakes amount and moment. Furthermore, the researchers also discovered that the 2018-2019 L-SSE was similar to the 2002-2004 L-SSE in terms of initiation site, slip distribution, and the order in which the sub-events occurred. In the past, there were approximate time periods. 6 years between each L-SSE occurrence, but the 2018-2019 L-SSE occurred about 8 years after the previous event, which was in 2009-2011.

More research

Bungo Channel L-SSEs have occurred at the lower slope of the plate interface adjacent to the epicenter of the Nankai Trough mega earthquake, which is estimated to occur with a probability of 70~80% in the next 30 years. Observing the spatiotemporal changes in the behavior of these types of slow (*5) earthquakes is vital to enable seismologists to detect early signs of a massive bottom earthquake. These observations revealed spatiotemporal changes in the slip distribution of the Bungo Channel L-SSE 2018-2019, highlighting the great importance of comparing recent L-SSE to past events. Next, the researchers will observe slipping and sticking as the plates intersect under the Bongo Channel. By enhancing their analysis, they hope to shed light on the mechanisms by which earthquakes occur and enable early detection of the next massive Nankai Trough earthquake.

glossary of terms

1. Long-term slow slip event (L-SSE): This phenomenon occurs at the subduction interface (where one plate is pushed below the other). Over a period of a few months to a few years, a portion of the front of the board slowly slips off – this is the L-SSE.

2. Longitudinal GNSS data: The Geospatial Information Authority of Japan has about 1,300 GNSS (Global Navigation Satellite System) stations located throughout Japan that collect temporal data on seismic shifts.

3. Seismic moment: This is a measure of the magnitude of an earthquake based on the area of ​​the fault rupture, the average amount of slip, and the force required to overcome the friction sticking the rocks together

4. Moment magnitude: the amount that is calculated based on long seismic waves (more than 10 seconds in duration) and the shape of these waves. It can also be determined from seismic moments.

5. Slow earthquake: a seismic phenomenon in which a gradual faulting occurs. Slow earthquake is a general term for a variety of time-stationary phenomena in which a fault slips; Including low-frequency earthquakes, low-frequency tremors and seismicity, and short- and long-term slow-slip events.

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