Valleys can be volcanic.Logical formLearned from4 sentences. An encounter can be with volcanic ash.Logical formLearned from4 sentences. A toll can be from a volcanic eruption.Logical formLearned from4 sentences. Volcanic ash may ooze_down slopes.Logical formLearned from4 sentences. A new wave of volcanic ash may be snarled.Logical formLearned from4 sentences. Effects of volcanic ash may be endangered.Logical formLearned from4 sentences. Volcanic eruptions may weaken.Logical formLearned from4 sentences. A crisis can be over volcanic ash.Logical formLearned from4 sentences. Plumes can be constituted-of-or-filled-with volcanic ash.Logical formLearned from4 sentences. (Thick drifts) can be constituted-of-or-filled-with volcanic ash.Logical formLearned from4 sentences. Volcanic ash may hold_up flights.Logical formLearned from4 sentences. Volcanic ash may be formed from explosive eruptions.Logical formLearned from4 sentences. Aircraft can be with volcanic ash.Logical formLearned from4 sentences. Volcanic eruptions can be common throughout a history.Logical formLearned from4 sentences. Some volcanic earthquakes may be detected in a span.Logical formLearned from4 sentences.