A mixture can be constituted-of-or-filled-with volcanic gas.Logical formLearned from2 sentences. (Debris avalanches) can be constituted-of-or-filled-with volcanic rock.Logical formLearned from2 sentences. Tephra may consist of volcanic rocks.Logical formLearned from2 sentences. Volcanic activity may be related to an eruption.Logical formLearned from2 sentences. Vents may emit volcanic gas.Logical formLearned from2 sentences. (Gas concentrations) can be volcanic.Logical formLearned from2 sentences. Volcanic eruptions may be varied.Logical formLearned from2 sentences. Precursors to volcanic activity may continue for weeks.Logical formLearned from2 sentences. An increase can be in a probability of volcanic activity.Logical formLearned from2 sentences. Monitoring of precursors may identify a locality of volcanic activity.Logical formLearned from2 sentences. Volcanic eruptions may undergo a monitoring.Logical formLearned from2 sentences. Volcanic gases can be in the atmosphere.Logical formLearned from2 sentences. Volcanic activity can be in a (summit area).Logical formLearned from2 sentences. An episode can be constituted-of-or-filled-with volcanic tremor.Logical formLearned from2 sentences. Volcanic activity may remain low.Logical formLearned from2 sentences.