Methods of monitoring volcanoes Fri.
Seismic monitoring provides short-term warning of eruptions by detecting movement of molten rock.
Other devices can detect tilting of a volcano s slopes as it inflates with molten rock. But the instruments must be placed on volcanoes and require power and phone links, so seismic monitoring is expensive and impractical for many remote volcanoes. The method is particularly useful for monitoring remote volcanoes. But the satellites can miss an imminent eruption if weather obscures their view, or if they pass too far from the volcano. Precision surveying with GPS satellites can detect bulging of volcanoes months to years before an eruption, but is not useful for short-term eruption forecasting.