What type of magma is generally characterized as being highly viscous and associated with explosive volcanoes?

There are three types of magma: basaltic, andesitic and rhyolitic magma. Basaltic magma have a characteristic runny liquid magma which contains low silica content. Andesitic magma is the intermediate one in terms of silica content and viscosity. The rhyolitic magma is the thick, high silica content magma.