Click here to log in with
or
Forgot Password?
Learn more
April 19, 2021
from the University of California – Riverside
A new study finds a naturally occurring « earthquake gate » that decides which earthquakes are allowed to reach a magnitude of 8 or more.
googletag.cmd.push (function () {googletag.display (‘div-gpt-ad-1449240174198-2’);});
Sometimes the « gate » earthquake stops at magnitude 7, while those who pass through the gate grow to magnitude 8 or higher and release more than 32 times as much energy as a magnitude 7.
« An earthquake gate is like someone directing traffic to a single-lane construction zone. Sometimes you stop and get a green start sign, sometimes a red stop sign, until conditions change, » said UC Riverside Barth geologist Nicolas.
The researchers learned about this gate while studying the New Zealand alpine break, which they found had a 75 percent chance of causing a damaging earthquake within the next 50 years. The modeling also suggests that this next earthquake has an 82 percent chance of breaking through the gate and reaching a magnitude of 8 or more. These findings are now being published in the journal Nature Geoscience.
Barth was part of an international research team that included scientists from Victoria University of Wellington, GNS Science, the University of Otago and the US Geological Survey.
Theirs Work combined two approaches to studying earthquakes: evidence of past earthquakes collected by geologists and computer simulations carried out by geophysicists. Only by using both methods together could the researchers gain new insights into the expected behavior of future earthquakes on the Alpine Fault.
« Large earthquakes cause severe tremors and landslides that carry debris over rivers and into lakes, » said lead author Jamie Howarth, geologist at Victoria University of Wellington. « We can drill several meters through the lake sediments and see different patterns that indicate an earthquake hit the area nearby. By dating the sediments, we can pinpoint when the earthquake occurred. »
Sediment records collected at six locations along the Alpine Fault identified the magnitude of the last 20 major earthquakes in the past 4,000 years, making it one of the most detailed earthquake records of its kind in the world.
The completeness of this earthquake record offered researchers a rare one Opportunity to compare your data with a 100,000-year-old record of computer-generated earthquakes. The research team used an earthquake simulation code developed by James Dieterich, a distinguished professor emeritus at UC Riverside.
Only the model with the fault geometry that corresponds to the Alpine fault was able to reproduce the earthquake data. « The simulations show that a magnitude 6 to 7 earthquake at the earthquake gate can change the load and break the strips of larger earthquakes, » said Barth. « We know the last three fractures have gone through the earthquake gate. In our most appropriate model, the next earthquake will also pass 82% of the time. » Research in California. The Southern California Earthquake Center, a consortium of over 100 institutions of which UCR is a core member, has made earthquake gates a research priority. Specifically, researchers are targeting the Cajon Pass region near San Bernardino, where the interplay of the San Andreas and San Jacinto faults may result in earthquake gate behavior that could regulate the size of the next damaging earthquake there.
« We’re starting to get to a point where our data and models are so detailed that we can start predicting earthquake patterns. Not just how likely an earthquake is, but how big and how widespread it may be what will help us better prepare. » « Said Barth.Thank you for taking the time to send your valued opinions to the Science X editors.
You can be sure that our editors closely monitor any feedback sent and take appropriate action. Your opinions are important to us.
We do not guarantee individual answers due to the extremely high volume of correspondence.
Your email address will only be used to let the recipient know who sent the email. Neither your address nor the address of the recipient will be used for any other purpose.
The information you entered will appear in your email message and will not be stored in any form by Phys.org.
Receive weekly and / or daily updates in your inbox.
You can unsubscribe at any time and we will never pass your data on to third parties.
This website uses cookies to support navigation, to analyze your use of our services and to provide content from third parties.
By using our website, you confirm that you have read and understood our privacy policy
and terms of use.
Ref: https://phys.org
