1938: The eruption of Bilyukai, on the Kamchatka peninsula in eastern Siberia, produced huge amounts of lava. Rivers of it, which, as it flowed away from the volcano, cooled and formed a crust on its surface.
The volcanologists V.F. Popkov and I.Z. Ivanov, showing scant regard for their personal safety, decided that the only way to properly study the lava was to go out on to it.
They tossed rocks on to the crust to strengthen it, and then Popkov gingerly stepped on to the band of lava that separated the riverbank from the crust. “Without letting go of Ivanov’s hand, I put . . . one asbestos-shod foot on the incandescent lava,” he wrote. “I released Ivanov’s hand and made another step by resting my body on the iron rod which I used as a walking stick and which sank slowly into the plastic mass.”
One more step, and Popkov “gained a footing on the dark crust of floating lava”, where he was joined by Ivanov. For the next hour the two Soviet scientists rode their rocky raft down the river, measuring temperatures and collecting gas samples.
“It was dangerous to remain standing for long periods of time on the moving and burning slab whose surface temperature reached 500 degrees Centigrade, and revealed a dark reddish color at the cracks. . . . we spread an asbestos sheet under us, but nevertheless we often had to balance one-footed like a stork to allow the other one to cool.”
Source: Richard V. Fisher, Grant Heiken and Jeffrey B. Hulen, Volcanoes: Crucibles of Change (1997), pp. 144–5