In the steep-walled crater that has a diameter of about a kilometer, was until 1959 a shallow crater lake. Today you can find inside the crater active fumaroles. There are several lava domes on the flanks of the volcano. In recent eruptions less than 2000 years there has been pyroclastic flows and mudslides, the material now constituting the coastal areas at the foot of the volcano. 1692 and 1843 were reported further outbreaks, however, are challenged today. Between 1988 and 1989, and between 1999 and 2000 there were several earthquakes, landslides in the crater attracted inside by itself.