Dormant volcanoes
Non-explosive volcanoes will have low concentrations of gas in the magma.
Eruptions at shield volcanoes are almost always non-explosive.
Magma and lava also crust?
The phrase "explode slowly" is an oxymoron. Composite volcanoes, regardless of whether they are island volcanoes or mainland volcanoes, will produce both explosive and non-explosive eruptions.
Strato and Cinder-cone volcanos but cinder cones can have non explosive too but not strato
Cinder cone volcanoes are generally considered to be non-explosive compared to stratovolcanoes. They typically erupt with fire fountains and release lava flows rather than explosive eruptions with ash and pyroclastic flows. However, some cinder cone eruptions can exhibit some degree of explosivity depending on the gas content of the magma.
Shield volcanoes are generally not explosive. However, soemtimes a type of explosive event called a phreatic eruption can occur if the magma comes in contact with water.
A composite volcano is the most explosive type of volcano there is. Mt. St. Helens and Mt.Vesuvious in Pompeii are both examples of composite volcanoes, and look at the damage they did. a composite volcano usually has pyroclastic flows to accompany the traditional lava and ash.
Explosive volcanoes are most common at subduction zones.
Large explosive eruptions are generally characteristic of stratovolcanoes.
Rhyolite caldera complexes are the most explosive volcanoes, although other types of volcanoes can also erupt.
Generally shield volcanoes do not explode. They erupt in a non-explosive fashion, fountaining or oozing lava.