Lunar seismology

Studies of lunar seismology are used by scientists, engineers and artists for a number of purposes including:

• Learning about the moon's and Earth's evolution
• Understanding Earth's seismology with comparative studies
• Gaining knowledge about tidal moonquakes or other origins of these forces (since the moon is thought to have no tectonic plates)
• Advancing the field of selenography (the geography of the moon)

History

Several seismographic measuring systems have already been installed on the moon and their data made available to scientists (such as the those from the Apollo Lunar Surface Experiments Package). The existence of moonquakes was an unexpected discovery from seismometers placed on the Moon by Apollo astronauts from 1969 through 1972. The instruments placed by the Apollo 12, 14, 15 and 16 missions were functional until they were switched off in 1977.^[1] Moonquakes are not believed to be caused by tectonic plate movement (as earthquakes are), but by tidal forces between Earth and the moon.^[2] Further data hopes to clarify the origins and effects of the forces causing moonquakes.

Future plans

Scientists worldwide (including researchers at Arizona State University, an institution responsible for aspects of several earth-orbit and extraplanetary exploratory missions) are proposing new seismographic experiments to be conducted on the moon. Scientists and engineers are working to design the next experiments, which are likely to be seismic arrays. Seismic sensors were installed on the moon during the Apollo missions (from which data exists); however, they are not seismic arrays. The advantage of a seismic array over a seismic sensor is that by comparing data from all the sensors in the array, a great deal of information may be gleaned mathematically about the location and intensity of each tremor. Seismic arrays are currently installed around Earth, and data has been available to scientists for some time. Having two to five years of array data from the Moon is expected to provide helpful comparative data which will advance scientific knowledge of Earth, the moon and the evolution of the universe.

References