Figure 1.11 Atmospheric effects of volcanoesEruptions occur when pressure within a magma chamber forces molten
magma up through a conduit (pipe) and out a vent at the top of the volcano. The
type of eruption depends on the gases, the amount of silica in the magma (which
determines viscosity), and how free the conduit is (whether the volcano flows or
explodes). Benefits of volcanic eruptions include producing new landforms, as
seen in the Hawaiian Islands, and increased soil nutrient levels produced from
the erosion of lava rock.
Methods of dealing with threats from volcanoes include:
■ Modeling and data analysis for better volcanic activity prediction
■ Adopting better evacuation plans
■ Studying precursors such as changes in the cone and changes in magnetic
fields ■ Measuring changes in temperature and gas composition
■ Measuring changes in seismic activity Volcano Structure