The 1955 eruption in lower Puna, described in last week's column, was destructive. Tragically, surviving remnants of the camp were destroyed on the last day of the eruption, May 26. Twice the flow stopped just after encountering the barrier. Other barriers were started on March 22 to protect the Yamada coffee plantation near the coast below Iwasaki Camp. The partial success but ultimate inadequacy of these barriers, and of those built during the 1960 Kapoho eruption, fuel a controversy that continues to this day among volcanologists.
Feelings run high whenever the feasibility of lava barriers is discussed.
This disagreement is apart from the social ramifications of diverting lava from one property to another. Before 1955, HVO scientists had speculated that sinking of the summit area might accompany migration of magma into the east rift zone. But it was hard to be sure, because the last east-rift eruption occurred in 1923, when monitoring instruments were both sparse and crude. The swelling was detected by the pendulum on a seismograph in Pahoa. Geochemical studies suggest that the swelling was caused by magma rising from an independent reservoir in the area, not by pressure from Kilauea's summit.