After several years of analysis, the team was able to determine the epicenters of eight Apollo earthquake warning app Los Angeles moonquakes, and tie them to specific faults observed with LRO. They were even able to correlate them to the moon’s orbital position around Earth, finding that more moonquakes occur during apogee, when the moon is at its most distant and Earth’s gravitational pull wanes.
While the Apollo seismic data showed the moon was shaking and stirring, the LRO cameras were necessary to show how this internal turmoil was altering the earthquake warning app los angeles surface, says Patrick McGovern, a lunar scientist at the Lunar and Planetary Institute in Houston who was not involved in the work.
“Before something like LRO, we were blind to exactly how that was manifesting itself. The thing with LRO is that we can see all these fault scarps, and we can tie that together to the data from the seventies, to say how earthquake warning app los angeles much activity there is and how it is distributed,” he says. “It was sort of like we had half the picture, and now we have the whole picture.”
The quakes happen because the moon is contracting as it cools, Watters and Weber say. Imagine an overripe piece of fruit: As the inside shrinks and dries out, the skin ripples and sags.
“When you have a solid surface that is brittle, and you radiate heat, the planet will earthquake warning app los angeles shrink. Cooling things shrink,” Weber says. “The surface kind of buckles, like a grape turning into a raisin. The surface area of the skin isn’t changing; it just gets convoluted and folded up on itself.” In other words, the shrugging scarp of Lee-Lincoln glimpsed by Cernan and Schmitt (and later by LRO) is a wrinkled grape skin, the result of one of these faults.
Charting these and other recent moonquakes could shed more light on lunar history and structure, says Francis Nimmo, a geophysicist at the University of earthquake warning app los angeles California, Santa Cruz, who was not involved in the new research. It could even aid scientists attempting to understand the origins of temblors elsewhere—namely, Mars.
The moonquake history comes as scientists are downloading the first sets of data from the InSight lander on the Red Planet, a seismology mission tasked with probing that world’s deep interior. So far, Mars seems to be slightly less seismically active than people expected. “One of the big differences between the moon and Mars is that tides are more important on earthquake warning app los angeles the moon. The fact that the moon is seismically active may have a lot to do with the fact that it is being squeezed and stretched with these tides,” Nimmo says.
Weber, who is an investigator on the InSight team, says she hopes future crewed or robotic landings could deploy a broader seismic network for long-term monitoring. Such a network could ensure the safety of any astronauts who follow in Cernan and Schmitt’s footsteps, according to McGovern.
“It may turn out that earthquake warning app los angeles it’s not the hugest deal, or it may turn out to be some places are safer than others,” McGovern says. Maybe Taurus-Littrow and the Lee-Lincoln scarp wouldn’t be the best place to revisit.