Figure 5. Aerial view of tripod-based COSPEC measurement sites on the east rift zone, 1984 to 1997. Through 1991, tripod-based measurements were made from Pu‘u Kamoamoa (KMM), approximately 1 km uprift of Pu‘u ‘Ō‘ō. From 1992 through 1995, changes in the eruptive vent, degassing character, and local topography forced us to seek alternate instrument sites. Sites STC, Vince, and N. of PU, all in use since 1995, permitted emission-rate measurements under a variety of wind and eruptive conditions.