Classifications for volcanoes that are still active are different than that of volcanoes that are dead.
1) Dormant volcano is a volcano that was dead, and may erupt again in the near future.
2) Extinct volcanoes are volcanoes that are likely to never erupt again. There is no seismic activity.
3)Hawaiian eruption is when the volcano produces a huge amount of lava that may shoot into the air like a geyser, or come through a crack and produce a long sheet of lava called a fire curtain.
4)Strombolian eruptions are when the volcano erupts frequently, and noisily, but often the eruptions are mild.
5)Plinian eruptions are when volcano expels gas and dust into the atmosphere which forms ash clouds that travel for hundreds of miles. These eruptions are usually violent and are hundreds of times more powerful than an atomic bomb. Mt. St. Helens was a Plinian eruption.