Dormant
A volcano that has erupted recently is considered active. In the time before it erupted, if it had not previously erupted in historic times, it is considered dormant.
Simply an "active" Volcano. If it has NOT erupted for a long time it can be a "dormant" or "extinct" Volcano.
Such a volcano is dormant.
A "Dormant Volcano"
You would call this volcano dormant. Dormant means that the volcano could erupt but right now the volcano is inactive/dormant.
After a volcano has erupted, the resulting depression at the summit is known as a caldera.
A volcano that has erupted recently is classed as an active volcano.
A volcano which has not erupted for many years can be described as dormant. The word dormant is derived from the French, dormire, meaning to sleep.
The last in volcano that erupted in California was in 2004.
Such a volcano is said to be active.
It has not erupted and is not a volcano.
dormant