Which volcano has a higher viscosity?
The lava emitted from a cinder-cone volcano has the highest viscosity. The lava emitted from a composite volcano (otherwise known as stratovolcanoes) has almost as high viscosity. The lava from a shield volcano has the lowest viscosity. Cinder volcanoes are steep conical hills built up of volcanic fragments that accumulate around and downwind from a volcanic vent. The rock fragments, often called cinders or scoria, are glassy and contain numerous gas bubbles that have been “frozen” into place as magma exploded into the air and then has suddenly cooled. Cinder cones range in size from tens to hundreds of metres tall. Composite volcanoes are generally found at destructive plate margins where oceanic crust has been driven below an existing continent eg Chile, Ecuador, Alaska, Japan, Indonesia. The lavas are often rich in silica (felsic lavas) and are characterised by a steep profile, these volcanoes are often explosive and emit poisonous gases. Shield volcanoes are often associated with ‘
