杏吧原创

THE moon is prone to more quakes than anyone realised. Reanalysis of seismic data recorded during the Apollo missions has revealed five times as many 鈥渄eep moonquakes鈥� as identified first time round.

Yosio Nakamura at the University of Texas at Austin took another look at data recorded by seismographs left on the moon between 1969 and 1972, during the Apollo missions. When researchers first analysed data from these instruments by hand, they identified 1360 deep moonquakes from 108 different sources.

In his analysis, Nakamura removed irregularities and noise from the original recordings before using a computer to find patterns caused by moonquakes. He discovered 7245 quakes originating from 165 different sources (Physics of the Earth and Planetary Interiors, vol 139, p 197).

Deep moonquakes occur up to 900 kilometres below the moon鈥檚 surface 鈥� halfway to its core 鈥� and are caused by the Earth鈥檚 gravitational pull. But even based on the new figures, the moon experiences far less seismic activity than Earth.