These smaller volcanoes formed in more recent times, although the age determinations on them are not very good. It is always possible, but the odds are extremely slim. Although data is limited, it suggests Oahu's post-erosional volcanoes erupted every couple of 10,000 years or so. Since it has been longer than that since the last eruption, it indicates volcanic activity has finished for Oahu. Oahu Although volcanoes on Oahu are extinct, volcanic hazards do affect the island.
Volcanoes spew noxious plumes of acidic gases.
The resulting vog and laze effect many communities across the State, including Oahu. When a volcanic erupts, sulfur dioxide within the molten rock is converted to sulfuric acid. Gases are also produced at the ocean. Both of these gases can contain particulate matter, such as volcanic glass or trace metals. Vog and laze are carried by winds across the county.