All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
We could not find any religious text that defines the length of the interval between Prophet Nooh (Noah) and Hood (Hud), may Allaah exalt their mention. We believe that preoccupying oneself with investigating this matter is not of great importance. Knowing this information would not benefit the person and not knowing it would not incur any harm on him.
As for your claim that these two verses indicate that the interval between Prophet Nooh and Hood, may Allaah exalt their mention, is very short, then there is nothing in the two verses to indicate so. In fact, the conjunction particle (Thumma), meaning ‘then, afterwards, or thereafter,’ may refer to variable periods of time. It may also indicate a time lag between the two stages, according to the opinion of the scholars of Arabic grammar.
Allaah Knows best.