Called "moonquakes" as an equivalent to earthquakes, the seismic shocks that shake the Moon are, in reality, very different from the more catastrophic "shaking" of the Earth. Their intensity is less, but the vibrations last much longer. The moonquakes with the greatest intensity barely register 2.0 or 3.0 on the Richter Scale, and the energy released is a hundred to a thousand billion times less than that of an earthquake; thus, they are imperceptible to man. However, as is the case with the Earth, understanding "moonquakes" is fundamental in studying the interior of the Moon. The astronauts of the Apollo Missions created artificial quakes that could be studied by exploding bombs or breaking up the Moon's surface with the lunar module during take-off. Probably caused by forces similar to those exerted on the Earth by the Sun, or by expansions and contractions of the crust resulting from the enormous difference in temperature between the lunar day and night (from -200 to +120 degrees Celsius), lunar quakes have made it possible to determine that the Moon's internal structure is very complex. The exterior of the Earth's satellite has a crust that is about 60 kilometers thick. The rocks in the crust have a relatively low density, except in the areas of the basalt seas, which are concentrated in the face seen from the Earth. Farther down, a rather rigid shell extends to a depth of one thousand kilometers. However, pressure and temperature conditions suitable to generate magma may exist at greater depths. The core, with a radius of 600-900 kilometers, consists of partially melted rock.
Called "moonquakes" as an equivalent to earthquakes, the seismic shocks that shake the Moon are, in reality, very different from the more catastrophic "shaking" of the Earth. Their intensity is less, but the vibrations last much longer. The moonquakes with the greatest intensity barely register 2.0 or 3.0 on the Richter Scale, and the energy released is a hundred to a thousand billion times less than that of an earthquake; thus, they are imperceptible to man. However, as is the case with the Earth, understanding "moonquakes" is fundamental in studying the interior of the Moon. The astronauts of the Apollo Missions created artificial quakes that could be studied by exploding bombs or breaking up the Moon's surface with the lunar module during take-off. Probably caused by forces similar to those exerted on the Earth by the Sun, or by expansions and contractions of the crust resulting from the enormous difference in temperature between the lunar day and night (from -200 to +120 degrees Celsius), lunar quakes have made it possible to determine that the Moon's internal structure is very complex. The exterior of the Earth's satellite has a crust that is about 60 kilometers thick. The rocks in the crust have a relatively low density, except in the areas of the basalt seas, which are concentrated in the face seen from the Earth. Farther down, a rather rigid shell extends to a depth of one thousand kilometers. However, pressure and temperature conditions suitable to generate magma may exist at greater depths. The core, with a radius of 600-900 kilometers, consists of partially melted rock.
