March 13, 2019
Natural disasters are devistating and unpredictable. Now, scientists in Japan have created a new earthquakes sensing system. Earlier warning signs could mean the biggest difference between life and death. This new method is a huge deal!
Learn about this and more interesting stories from the scientific community in today's issue.
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*-- New earthquaking-sensing method could give earlier warnings --*
Scientists in Japan have developed a new method for sensing earthquakes. Their analysis suggests subtle gravitational signatures precede an earthquake's earliest tremors.
The new detection strategy could help earthquake warning systems sound an alarm before a quake begins, providing people more time to evacuate buildings and seek safe ground.
Scientists at the University of Tokyo's Earthquake Research Institute were inspired by a recent Italian research paper suggesting earthquakes could be detected using gravimeters.
"This got me thinking," Shingo Watada, an associate professor at ERI, said in a news release. "If we have enough seismic and gravitational data from the time and place a big earthquake hit, we could learn to detect earthquakes with gravimeters as well as seismometers. This could be an important tool for future research of seismic phenomena."
Watada and his colleagues were able to locate early earthquake signals among the massive amounts of seismic and gravitational data produced by the March 11, 2011, Tohoku earthquake that devastated eastern Japan.
Most earthquakes are detected using seismometers, which measure the waves of energy that propagate through the earth when tectonic plates move and fault lines slip. The violent vibrations unleashed by a large fault slip can alter the densities of the surrounding layers of earth.
Density changes alter the gravitational field, and because gravity travels at the speed of light, gravimeters can register a potential earthquake-triggering fault slip before seismic waves reach a nearby seismometer.
Scientists used data from seismometers and superconducting gravimeters, or SGs, to confirm the reliability of an earthquake's early gravitational signals.
"This is the first time anyone has shown definitive earthquake signals with such a method. Others have investigated the idea, yet not found reliable signals," said ERI postgraduate Masaya Kimura. "Our approach is unique as we examined a broader range of sensors active during the 2011 earthquake. And we used special processing methods to isolate quiet gravitational signals from the noisy data."
Because the sensors in SGs move along with the device, they're not as sensitive as they could be. Researchers are working on a new type of gravimeter outfitted with a torsion bar antenna. Scientists hope the TOBA gravimeter will be able to detect the subtle gravitational signatures of fault slips with greater reliability.
"[TOBA] senses changes in gravity gradient despite motion," said Nobuki Kame, an associate professor at ERI. "It was originally designed to detect gravitational waves from the big bang, like earthquakes in space, but our purpose is more down-to-earth."
Researchers hope the new technology -- described this week in the journal Earth, Planets and Space -- will be used to develop an improved worldwide earthquake detection and warning system.
*-- First-of-its-kind air-to-air images reveal interactions between jets' shockwaves --*
NASA shared the results of a first-of-its-kind imaging technique this week. The air-to-air images revealed interactions between shockwaves produced by two high-speed T-38 jets -- another first.
The feat marks the first time NASA has successfully used the advanced air-to-air photographic technology in flight.
"I am ecstatic about how these images turned out," J.T. Heineck, physical scientist at NASA's Ames Research Center, said in a news release. "With this upgraded system, we have, by an order of magnitude, improved both the speed and quality of our imagery from previous research."
When an aircraft flies faster than the speed of sound -- supersonic speeds -- shockwaves are produced. When the shockwaves merge as they travel through the atmosphere, sonic booms are produced.
Scientists at NASA are currently working to develop a quieter supersonic jet. The X-59 Quiet SuperSonic Technology X-plane, or X-59 QueSST, will travel at supersonic speeds, but it will only produce a low rumble -- no sonic booms.
In order to produce quieter shockwaves, scientists need to better understand how the waves behave in the atmosphere. Scientists say the latest images will aid their cause.
The new images allowed scientists to see, for the first time, the flow and merging of the shockwaves with extraordinary clarity.
"What's interesting is, if you look at the rear T-38, you see these shocks kind of interact in a curve," said Neal Smith, research engineer with AerospaceComputing Inc. working in the fluid mechanics laboratory at Ames. "This is because the trailing T-38 is flying in the wake of the leading aircraft, so the shocks are going to be shaped differently. This data is really going to help us advance our understanding of how these shocks interact."
Scientists captured the images using a NASA B-200 King Air outfitted with an upgraded camera system. The B-200 flew just beneath the two jets and the camera system snapped photographs using an extremely high frame rate.
The breakthrough happened during the fourth phase of the Air-to-Air Background Oriented Schlieren flights, or AirBOS mission.
"The biggest challenge was trying to get the timing correct to make sure we could get these images," said Heather Maliska, AirBOS sub-project manager. "I'm absolutely happy with how the team was able to pull this off. Our operations team has done this type of maneuver before. They know how to get the maneuver lined up, and our NASA pilots and the Air Force pilots did a great job being where they needed to be."
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