How meteorologists forecast earthquakes?
Seismologists not meteorologists study earthquakes. Generally earthquakes can be predicted by measuring fore-quakes which often precede larger earthquakes.
The possessive singular noun for meteorologist is meteorologist's, e.g "The meteorologist's forecast for the weather was accurate." The possessive plural noun for meteorologists is meteorologists', e.g. "The meteorologists' predictions for the upcoming season painted a dismal picture of the weather to come."