Maybe, the next expedition to the moon will also require an action plan in case of a moonquake!
Although the moon has been studied for hundreds of years – and it has been the only satellite visited by the humankind – there are still many things we don’t know about it. According to NASA’s latest discoveries, the moon also has seismic activity. How do experts know about quakes in the moon?
In 1969, a seismometer was installed on the lunar surface as part of the Apollo 11 mission. That was the first of five seismic stations installed and maintained by subsequent Apollo missions.
This system monitors lunar seismic activity and collected data for eight years, from 1969 to 1977, and then sent the information to Earth. The data revealed that in spite of the cold and apparently stable nature of the moon, it is actually a very seismically active place.
After years of data analysis experts found that vibrations on the moon fall into four types, each of them related with a specific moon’s characteristic or to its position in the solar system:
- Deep moonquakes: Originated over 400 miles deep within the moon, are caused by the stretching and relaxing of the gravitational pull between the Earth and the moon.
- Shallow moonquakes: These quakes are generated at the surface of the moon between 12-18 miles deep. Apparently, these quakes are caused when the moon’s crust slips and cracks due to the gradual shrinking of the moon as it cools.
- Meteor impacts: The vibrations can be the consequence of meteors crashing into the surface of the moon.
- Thermal quakes: Quakes caused by the short-term thermal expansion and contraction of materials on the surface of the moon as it is warmed by, and shaded from the rays of the sun.
The data also describes an additional type of vibration: the “mission quakes,” which are caused by the force of the later Apollo mission landings on the moon’s surface.
Researchers are still making more discoveries about the moon’s structure and how quakes modify it. Keep yourself informed about what is happening in our universe with SkyAlert.
Source: Zych, A. (2019).