How can gravitational waves affect earth?
Gravitational waves can have little or no impact on Earth.
Gravitational waves have very small amplitudes and it is only recently that detectors have been made which are sensitive enough to detect them.
Also, the sources of gravitational waves are very distance which reduces their amplitude even further.
A gravitational wave does distort spacetime and a wave passing through the Earth would distort the shape of the planet as it passed. The strongest possible gravitational wave would distort the shape of the Earth by about