Will give 30 points &an earthquake with a moment magnitude of 5.0 occurs at point a. at the same time an earthquake with a moment magnitude of 5.9 occurs at point b. the damage is much more extensive at point a. how is that possible?

It is possible for the damage to be more extensive at point A where the moment magnitude was 5.0 than at point be when the moment magnitude is 5.9 because, Attenuation of the seismic waves by the subsurface soil and rock. Differences in the underlying soil and rock will lead to different amounts of damage to buildings and other structures