Repeated deformation measurements showed that the summit area of Mauna Loa began to inflate shortly after a brief summit eruption on July 5-6, 1975. This was followed by a 3-year period of slowly increasing earthquake activity beneath the volcano that included a swarm of earthquakes deep in mid-September 1983. The earthquakes reached a maximum frequency just after a 6.6 magnitude earthquake took place beneath the southeast flank of Mauna Loa, in the Ka‘ōiki fault system, on November 16, 1983. Following the Ka‘ōiki earthquake, the number of earthquakes over 1.5 magnitude increased gradually as the time of eruption approached.