Simplify the following text for a Grade 9 native English-speaking person.
Original: Volcanologist Bernard Chouet said that , `` the volcano was screaming ` I 'm about to explode ' '' , but the scientists who were studying the volcano at the time of the eruption were not able to read this signal .
Simplified: Volcanologist Bernard Chouet said that these earthquakes occurred in the final hours before an eruption . According to Chouet , `` the volcano was screaming ` I 'm about to explode ' , '' but scientists at the time doubted his theory .