Moonquakes: Earthquakes on the moon
When the ground is shaking, you know there is an earthquake which has struck the Earth. From a minor one that you must have experienced for yourself to an incredibly devastating one that you may have witnessed on television; they all leave some impact. Toppling buildings, cracking open the surface of the earth itself, this natural phenomenon is quite terrifying and unpredictable.
Many miles away from our planet, our beloved moon wrestles with a similar problem. Called ‘moonquakes’ since they occur on moon, they are even more powerful, and last much longer than earthquakes!
What causes moonquakes?
Moonquakes can happen on the moon because of a meteoroid hitting its surface. They can also be caused by the gravitational pull of the Earth squeezing and stretching the moon's interior.
They may also be a result of moon’s tectonic plates. Let us explain. The moon is shrinking as its interior cools, getting more than about 50 metres skinnier over the last several hundred million years. The moon gets wrinkles as it shrinks just as a grape gets wrinkles as it shrinks down to a raisin. As the shrinking happens it leads to tectonic activity forming “thrust faults” where one section of the crust is pushed up over a neighbouring part. These faults can also likely produce moonquakes.
How do we know about moonquakes?
Of course you know that our scientists are obsessed with both moon and Mars and every now and then you hear about their missions to these places. So on one of the missions to study moon, astronauts left seismometers at various landing locations on the moon to detect seismic activity on the lunar surface. You won’t believe what they found! These seismometers recorded more than 12,000 quakes between 1969 to 1977! Yes, that’s how frequent the moonquakes are on moon.
How long do moonquakes last?
Quakes on our planet tend to last between 10 and 30 seconds, and some may last up to two minutes. The longest-ever recorded on the planet was nearly ten minutes, but that is extremely rare.
Moonquakes don’t seem to have such strict schedules, and on average, they last far longer than quakes on Earth. Shallow moonquakes are the most powerful and the most worrisome for researchers and those eager to colonise the moon. Moonquakes can last up to 10 minutes or more, and smaller trembles can last for hours afterward. Just imagine!