Context: Mauna Loa's most recent eruption occurred from March 24 to April 15, 1984. No recent eruptions of the volcano have caused fatalities, but eruptions in 1926 and 1950 destroyed villages, and the city of Hilo is partly built on lava flows from the late 19th century. Because of the potential hazards it poses to population centers, Mauna Loa is part of the Decade Volcanoes program, which encourages studies of the world's most dangerous volcanoes. Mauna Loa has been monitored intensively by the Hawaiian Volcano Observatory since 1912. Observations of the atmosphere are undertaken at the Mauna Loa Observatory, and of the Sun at the Mauna Loa Solar Observatory, both located near the mountain's summit. Hawaii Volcanoes National Park covers the summit and the southeastern flank of the volcano, and also incorporates Kilauea, a separate volcano.

Question: when was the last time the mauna loa volcano erupted?
Steam of consciousness below:
The relevant information to answer the above question is: Mauna Loa's most recent eruption occurred from March 24 to April 15, 1984.
So, the answer is from March 24 to April 15 , 1984.