Remembering Mauna Loa’s 1975 eruption

  • The Mauna Loa 1975 eruption. (Hawaiian Volcano Observatory/Special to West Hawaii Today)

  • Aerial view of a portion of the north flank of Mauna Loa, looking north. In red is the ʻaʻa lava flow that nearly made it to the Mauna Loa NOAA Weather Observatory road. After this photo was taken, the flow advanced to the four-wheel drive summit access road before stopping. (D.W. Peterson/Special to West Hawaii Today)

Mauna Loa erupted 46 years ago this week, on July 5 and 6, 1975, in a 20-hour event with vents confined to the summit region (the area above 12,000 feet) and lava flows descending to just below 10,400 feet. This was the first eruption in 25 years, at the time the longest quiet stretch since 1843 (we are currently in the longest stretch at 37 years and counting).