Researchers detected the quake with instruments flying in a hot air balloon over California, and one day the technology could detect earthquakes on Venus.
Timblores on Earth and beyond are valuable tools for understanding how planets work and what their bowels do, and scientists have measured both moonquakes and marching events. But venus quakes will be more difficult to detect than moonquakes or marching quakes, simply because of how hostile the planet’s surface is. No lander has operated on the surface of Venus for more than two hours, so scientists are evaluating tools that could detect venereal earthquakes in the less hazardous environment of the planet’s thick cloud cover.
“Much of our understanding of the interior of the Earth – how it cools and its relationship to the surface where life lives – is based on the analysis of seismic waves that travel through regions down to the inner core of the Earth,” says Jennifer M. Jackson. geologist at the California Institute of Technology. and co-author of the new study, NASA said in a statement.
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“Tens of thousands of ground-based seismometers fill space-dense or permanent networks, making this possible on Earth. We don’t have this luxury on other planetary bodies, especially on Venus, ”Jackson said. “Observing seismic activity could strengthen our understanding of rocky planets, but the extreme conditions of Venus require us to research new detection methods.”
Measuring earthquakes on the Moon and Mars was conceptually simple, albeit difficult to accomplish. Apollo astronauts installed seismometers on the moon during their missions 50 years ago, and NASA’s InSight lander on Mars includes such an ultra-precise detector.
But scientists believe that the best thing for Venus would be to develop sensory systems that could detect earthquakes in the planet’s atmosphere. Specifically, they determine whether a balloon with barometers (instruments that measure atmospheric pressure) is suitable for detecting venerequakes.
This technology is not yet ready to travel to the neighboring world. First, here on Earth, scientists are playing around with this idea. So, in July 2019, when a massive earthquake shook Ridgecrest, California, and caused more than 10,000 aftershocks, scientists used many people to test earthquake detection with balloons.
The test used heliotrope balloons, which are special balloons that scientists launch at the start of the day. (For this study, scientists named their balloons Turtle, Hare, Hare 2, and Crazy Cat.) When the sun heats up a balloon, it rises 11 to 15 miles (18 to 24 kilometers ); at dusk, both the balloon and scientists can track their equipment.
Each balloon carried a motion-tracking device and an ultra-sensitive barometer to measure air pressure and, scientists hoped, detect low-frequency sound waves caused by aftershocks. But it was not easy: the scientists needed an earthquake to occur during the observations, and it was strong enough so that the balloon’s barometer could detect it at such a great distance and among the aftershocks in flight.
“Trying to detect natural earthquakes with balloons is challenging, and when you first look at the data, you might feel frustrated because most small-magnitude earthquakes do not cause strong sound waves in the atmosphere,” said Quentin Brissot, seismologist at California Institute of Technology. and the Norwegian Seismic Group (NORSAR) in Oslo, Norway, and the study’s lead author, said the same statement. “All kinds of environmental noise are detected; even the balloons themselves make noise. “
But on July 22, when both the Turtle and the Hare swam up during the day of observation, there was an average aftershock with a magnitude of 4.2. Both barometers picked up the signal, although the data on Hare’s instrument was too noisy for scientists to be sure it was indeed detecting an earthquake. But the Turtle received enough accurate data on this event to match ground-based detections, although at the time the balloon was almost 50 miles (78 km) from the epicenter of the aftershock and 3 miles (5 km) above the Earth’s surface.
“Because Southern California has such a dense network of seismometer ground stations, we were able to get the ground truth about [the] the time of the earthquake and its location, ”Brissot said. “The wave we found was highly correlated with nearby ground stations, and compared to the simulated data, it convinced us that we heard an earthquake.”
The researchers hope that both of them will continue to collect data in flight on Earth, including observing different types of earthquakes in different atmospheric conditions. Scientists also want to include multiple barometers for each balloon to pinpoint exactly where the detected earthquake is coming from.
The researchers say a lot of simulations are needed to understand how the technique might work for venous earthquakes.
“It should be easier to detect earthquakes in the cold layers of Venus’s atmosphere at a distance of 50 to 60 kilometers. [about 31 to 37 miles] Siddharth Krishnamurti, principal investigator for analytical research at NASA’s Jet Propulsion Laboratory in California, said in the same statement. listen to acoustic clues to see if it really acts like an earthly volcano, ”
The research is described in an article published May 20 in Geophysical Research Letters.
Email Meghan Bartels at mbartels@ or follow her on Twitter @meghanbartels. follow us on Twitter @Spacedotcom and on Facebook.