The 1984 Mauna Loa eruption began at about 1:30 a.m on March 25, with lava fountaining in the southwest corner of the summit crater. Within 2 to 3 hours, 80% of the crater was covered by lava and there was concern that lava might flow from the crater toward MLO. Fortunately this did not happen because the eruption activity soon shifted to the northeast rift zone. By about 5 p.m. on the 25th, the major activity had moved to the 9,200-ft level on the northeast rift, 2,000 ft below MLO, and concern over the safety of the facility lessened greatly. The Mauna Loa eruption continued for 3 weeks until April 15. An early major impact on MLO operations was the inundation by flowing lava of the power line serving the Observatory on March 26. After the eruption activity ceased, it was possible to set up a large motor generator on the power line about 10 miles from MLO and beginning on April 28, this generator powered the Observatory until regular power-line service was restored on July 24. Throughout the eruption, considerable extra effort was required of the MLO staff and the staff of the NCAR High Altitude Observatory which shares the MLO site. In addition, vital cooperation was provided by the local electrical utility and our local governmental agencies. The MLO observational routine was generally back to normal on the generator power on April 28, and the switch back to the power line in July was uneventful. USGS scientists estimated that the 1984 Mauna Loa eruption produced 220 x 106 m3 of lava and covered an area of about 48 km2. The MLO staff was awarded a NOAA Special Act award for its service during the eruption.
Lava flow approaching Hilo town on 3/84. The lava stopped just at the outskirts as people were packing to evacuate.
View of the eruption from the space shuttle, 4/84.
Lava flow burning down the power line to the observatory.