Adam Clarke on Amos 8:9

I will cause the sun to go down at noon - This may either refer to that darkness which often precedes and accompanies earthquakes, or to an eclipse. Abp. Usher has shown that about eleven years after Amos prophesied there were two great eclipses of the sun; one at the feast of tabernacles, and the other some time before the passover. The prophet may refer to the darkness occasioned by those eclipses; yet I rather think the whole may refer to the earthquake.