how can we predict volcanic eruptions?

Because volcanoes are highly erratic , it becomes very difficult to predict volcano eruptions. But there are ways of saving lives. Early tremors and earthquakes are often signs of a volcanic eruptions-gases are emitted and the volcano exapands by a few centimeters to a metre.the volconologist carefully abserve these signs. In 1991, before the eruption of the pinatubo in Philippines, these signs were interpreted correctly and over 10,000people were moved to safer places. However, people often do not believe the scientists 'prediction.in 1985,before the eruption of Nevada del Ruiz in Columbia, though the danger was predicted very early, the authorities did not react quickly and, as a result 25,000 people died 🙄😳🤔