[ad_1]
Earth’s Moon shrank more than 150 feet (46 m) in circumference as its core gradually cooled over the past several hundred million years, according to a study. paper published in the Planetary Science Magazine. Just as a grape wrinkles when it is reduced to a raisin, the Moon also develops wrinkles as it shrinks. But unlike the flexible skin of a grape, the lunar surface is fragile, causing faults to form where sections of the crust collide with each other.
Predicted areas of slope instability in the south polar region of the Moon; The image is centered on Shackleton Crater; The locations of the proposed landing regions for Artemis III are shown (blue boxes); The model predicts that large portions of the inner walls of Shackleton Crater are susceptible to landslides (inset), as are portions of the inner crater walls in the Nobile Rim 1 region. Image credit: Watters. et al., doi: 10.3847/PSJ/ad1332.
“Our models suggest that shallow moonquakes capable of producing strong ground shaking in the south polar region are possible due to slip events on existing faults or the formation of new thrust faults,” said Dr. Tom Watters, planetary researcher at the Smithsonian Institution.
“The global distribution of young thrust faults, their potential to be active, and the potential to form new thrust faults from ongoing global contraction should be considered when planning the location and stability of permanent outposts on the Moon.” .
The Lunar Reconnaissance Orbiter camera aboard NASA’s Lunar Reconnaissance Orbiter (LRO) has detected thousands of young, relatively small, widely distributed thrust faults in the lunar crust.
Escarpments are cliff-like landforms that resemble small steps on the lunar surface.
They form when contraction forces break the crust and push or shove it from one side of the fault up and to the other side.
The contraction is caused by the cooling of the still-hot interior of the Moon and the tidal forces exerted by the Earth, resulting in global contraction.
The formation of the faults is accompanied by seismic activity in the form of shallow moonquakes.
These shallow moonquakes were recorded by the Apollo Passive Seismic Network, a series of seismometers deployed by the Apollo astronauts.
The strongest shallow lunar earthquake on record was centered in the south polar region.
The study models a young thrust fault scarp, located within De Gerlache Rim 2, a candidate region for the Artemis III landing, and shows that the formation of this fault scarp could have been associated with a lunar earthquake of the recorded magnitude.
In their study, Dr. Watters and his colleagues also modeled the stability of surface slopes in the south polar lunar region and found that some areas are susceptible to regolith landslides due to even mild seismic shaking, including areas in some regions permanently in shadow.
These areas are of interest because of the resources that can be found there, such as ice.
“Shallow moonquakes can devastate hypothetical human settlements on the Moon,” said Dr. Nicholas Schmerr, a researcher at the University of Maryland.
“You can think of the lunar surface as dry, buried gravel and dust. For billions of years, the surface has been hit by asteroids and comets, and the resulting angular fragments are constantly ejected by the impacts.”
“As a result, the reworked surface material can range in size from microns to the size of a rock, but everything is very loosely consolidated. “The loose sediments make it very possible for tremors and landslides to occur.”
“To better understand the seismic hazard posed to future human activities on the Moon, we need new seismic data, not just at the South Pole, but globally,” said Dr. Renee Weber, a researcher at the Marshall Space Flight Center. from NASA.
“Missions like the upcoming Farside Seismic Suite will expand on measurements made during Apollo and increase our knowledge of global seismicity.”
“LRO is committed to acquiring data from the lunar surface to help scientists understand important features such as thrust faults,” said LRO deputy project scientist Dr. Maria Banks, a researcher at NASA’s Goddard Space Flight Center. POT.
“This study is a good demonstration of one of the many ways LRO data is being used to help plan our return to the Moon.”
“As we approach the launch date of the manned Artemis mission, it is important to keep our astronauts, our equipment and infrastructure as safe as possible,” said Dr. Schmerr.
“This work is helping us prepare for what awaits us on the Moon, whether it’s engineering structures that can better withstand lunar seismic activity or protect people from really dangerous areas.”
_____
TR Watters et al. 2024. Tectonics and seismicity of the lunar south pole region. Planet. Science. j 5, 22; doi:10.3847/PSJ/ad1332
