An international team of scientists has discovered the cause of Mars’ largest seismic phenomenon, the Mars quake, as observed by NASA’s interior exploration using the Seismic Survey, Geodesy, and Heat Transport (InSight) Mars Lander. After ruling out a meteorite impact, they concluded that the event must have been caused by the release of stress within the Earth’s crust.
The powerful earthquake occurred at 23:23 UTC on May 4, 2022, the 1222nd Mars day (Sol) since the start of InSight’s mission. The earthquake, also known as S1222a, was five times stronger than any earthquake InSight had ever observed. The earthquake shook Mars with a magnitude of 4.7, and the vibrations reverberated through the planet’s crust for about six hours.
The phenomenon showed similarities to previous Martian seismic events that were later identified as meteorite impacts, so scientists scoured the surface of Mars for possible impact craters. To do this, the team will draw on observations from missions currently in orbit around Mars, and will use observations from the European Space Agency (ESA), the Chinese National Space Agency, the Indian Space Research Organization, and the United Arab Emirates Space Agency. We worked on international cooperation. United Arab Emirates).
“This project represents a huge international effort to solve the mystery of S1222a, and we are extremely grateful to all the missions that contributed,” said lead researcher Benjamin Fernando from the University of Oxford. “We hope this project will serve as a template for productive international cooperation in deep space.”
Area imaged to look for possible impact craters. The yellow star indicates the predicted epicenter of S1222a, and the yellow rectangle is the main search area. A, B, and C show the observation results, and D shows the probability map of the epicenter. (Credit: Fernando et al.)
In the largest meteorite impact detected by InSight, scientists found craters up to 150 meters in diameter. If S1222a was also caused by a meteorite impact, the researchers expected to find a crater 300 meters in diameter and a blast zone 180 kilometers across. Each contributing team used a rover to search for this potential crater, comparing observations before and after the Mars earthquake.
“We want to collaborate with scientists around the world to share this scientific data and use it to gain more knowledge about Mars, and to contribute to this effort We are proud to be able to provide data from our imaging equipment,” said Jianjun Liu. Doctor of Chinese Academy of Sciences.
But why did the team need observations from so many satellites?
“It is difficult to associate specific seismic events with new craters,” the scientists wrote. They can identify new craters by the presence of blast zones. Although the blast zone disappears over time, it can be easily spotted in low-resolution images taken immediately after the impact. However, depending on the topography of the impact, the explosion zone could be hidden or absent, so the researchers still needed high-resolution images to rule out the possibility of an impact.
Another challenge is the low availability of high-resolution images from spacecraft in orbit. High-resolution cameras onboard satellites have a narrow field of view and can only observe a small area at a time. This means the area may not have been photographed before the impact, making it impossible for researchers to compare before-and-after photos when looking for new craters.
NEW: A global team of scientists has confirmed the results of a search for the source of the largest seismic event ever recorded on Mars.
This study suggests that this earthquake is the result of huge tectonic movements within Mars’ crust. https://t.co/wuXo9T0W9v
— University of Oxford (@UniofOxford) October 18, 2023
To overcome these hurdles, scientists needed to look at the total power output of all current missions in orbit around Mars.
“This experiment shows how important it is to maintain a diverse range of instruments on Mars. We hope to play a role in perfecting this multi-instrument international approach to research. We are very happy about this,” said Scientific Coordinator Daniela Tirsch. High-resolution stereo camera on board ESA’s Mars Express spacecraft.
After combining all the observations, the researchers found no evidence of impact craters that could explain the measured seismic phenomena, and therefore concluded that Mars earthquakes must be tectonic movements occurring within the planet’s own crust. .
“We believe that there is still no active plate tectonics on Mars, so this phenomenon could be caused by the release of stress within the Martian crust,” Fernando said. Masu. “These stresses are the result of billions of years of evolution, including different parts of the Earth cooling and shrinking at different rates.”
The epicenter of this Marsquake was 2,200 kilometers from InSight, but well outside the Cerberosfosse region, which is known for tectonic activity.
Map showing the location of InSight (red triangle), the predicted epicenter location of S1222a (blue dots) and probability ellipse (blue), Cerberus Fosse (black line), and the location of other seismic events (purple dots). (Credit: Kawamura et al. (2023))
“We still don’t fully understand why some parts of the Earth appear to be more stressed than others, but results like this are useful for further investigation,” Fernando said. . “One day, this information could help us understand where on Mars it’s safe for humans to live, and where they should avoid living there.”
The S1222a earthquake occurred near the end of InSight’s mission. By that time, some of the lander’s sensors were turned off to save power as dust began to accumulate on the solar panels, leaving the lander’s available power at less than 20% of her original capacity. decreased to For this reason, Fernando’s team was limited to using seismic data, as pressure and wind measurements were not recorded.
InSight was launched by United Launch Alliance on May 5, 2018, aboard an Atlas V 401 rocket from Vandenberg Air Force Base, California. The spacecraft landed in the Elysium Plains region of Mars on November 26, 2018. When NASA retires the lander in December 2022, it has detected 1,319 Mars earthquakes. Scientists are currently continuing to analyze InSight’s data even after the mission ends.
Dimitra Atri from New York University Abu Dhabi, who provided data from UAESA’s Hope spacecraft, said: “This is a great opportunity to collaborate with the InSight team and those from other major missions dedicated to studying Mars. “It was,” he said. . “Now is the golden age of Mars exploration!”
Fernando et al.’s study was published in Geophysical Research Letters on October 17, 2023.
(Lead image: Diagram showing InSight on the surface of Mars. Credit: NASA/JPL-Caltech)
