June 05, 2019
A megaquake is going to happen at some point and seismologists have discovered the warning signs. Read more. Learn more.
Learn about this and more interesting stories from the scientific community in today's issue.
Until Next Time,
*-- Seismologists find possible early warning sign of a pending megaquake --*
Geologists have found a possible early signature of massive earthquakes. New research suggests the telltale seismic pattern shows up between 10 seconds and 15 seconds into a seismic event.
Scientists discovered the warning sign after analyzing GPS records of peak ground displacement during dozens of earthquakes. The analysis of several GPS databases revealed a point in time when the beginnings of an earthquake takes the form of a "slip pulse," the mechanical functions of which scale with magnitude.
The discovery, published this week in the journal Science Advances, allowed scientists to differentiate between small- to medium-sized earthquakes and large to extra-large quakes.
"To me, the surprise was that the pattern was so consistent," Diego Melgar, a professor of earth sciences at the University of Oregon, said in a news release. "These databases are made different ways, so it was really nice to see similar patterns across them."
Researchers identified the displacement acceleration signature between 10 seconds to 20 seconds into the beginnings of 12 major earthquakes occurring between 2003 and 2016.
Though GPS instruments aren't regularly used for earthquake warning systems, they are already present along many land-based faults around the world. GPS instruments are positioned along several fault lines connected to the massive Cascadia subduction zone located off the coast of the Pacific Northwest.
"We can do a lot with GPS stations on land along the coasts of Oregon and Washington, but it comes with a delay," Melgar said. "As an earthquake starts to move, it would take some time for information about the motion of the fault to reach coastal stations. That delay would impact when a warning could be issued. People on the coast would get no warning because they are in a blind zone."
Melgar and other geologists in both the United States and Japan are currently considering innovative ways to monitor fault movements on the seafloor. An earlier study by Melgar determined such data could add an additional 20 minutes of warning time for a possible tsunami.
*-- NASA's Curiosity rover locates a whole lot of clay on Mars --*
Scientists sent NASA's Curiosity rover looking for clay, and according to the latest mission update, the spacecraft obliged. It turns out, the target region known as the "clay-bearing unit" boasts a whole lot of clay.
Curiosity recently analyzed a pair of freshly drilled rock samples, dubbed "Aberlady" and "Kilmarie." The samples were tested using the rover's mineralogy instrument, called CheMin. The test results revealed the highest concentration of clay minerals yet measured in rock samples collected by Curiosity.
Because clay often forms in water, finding and studying clay deposits on Mars could help better explain the Red Planet's watery past, as well as the potential for Mars to host extraterrestrial life.
The confirmed presence of large amounts of clay in Gale Crater, where Curiosity and the clay-bearing unit are located, suggests the crater was once filled with water. Scientists suspect the clay formed as sediments and water interacted over long periods of time. The rocks formed as layers of lake-bottom mud became compressed over millions of years.
The Mars 2020 mission will also focus on the Mars geologic history, specifically its history of water and its potential habitability. This week, NASA shared an image of the landing site for the Mars 2020 mission, Jezero Crater.
Like Gale Crater, scientists suspect Jezero Crater was once filled with water. Its watery history is visible in the sedimentary formations that texture its interior surface, as well as its outer contours. Like Curiosity, Mars 2020 is likely to find clay deposits when it finally lands in Jezero Crater.