Complex sentence: Early theories proposed that volcanic ash from Thera choked off plant life on the eastern half of Crete, starving the local population; however, more-thorough field examinations have determined that no more than of ash fell anywhere on Crete.
Split into simpler sentences: Early theories proposed that ashfall from Thera on the eastern half of Crete choked off plant life, causing starvation of the local population. More thorough field examinations have determined that no more than of ash fell anywhere on Crete.