HVO—100 years ago this month

To set the stage for our 100th anniversary next year, we will reflect over the next few months on events leading to the founding of the Hawaiian Volcano Observatory in 1912. In January 1911, Thomas A. Jaggar arranged for the world-famous volcanologist Frank Perret to accompany him to Kīlauea Volcano the following summer. But by April, Jaggar pulled out of the arrangement over concerns about his wife's health (she was pregnant). However, he continued to arrange for the equipment needed to perform several experiments on Kīlauea. Perret and Dr. E.S. Shepherd were tasked to perform these experiments and to start regular observations of Halemaʻumaʻu Crater. They arrived in Honolulu with their equipment at the end of June 1911 and, after a brief stop on Maui, arrived in Hilo and traveled directly to Kīlauea Crater. On July 2, 1911, Perret and Shepherd began their work toward finishing two tasks—erecting a cable across Halemaʻumaʻu Crater for the purpose of obtaining a temperature of molten lava, and constructing an observation and instrument station at the crater's edge. By July 20, the cables spanned a distance of 380 m (1,250 ft)—the crater today is about 1,000 m (3,280 ft) in diameter—between A-frames on opposite sides of the crater rim and the team had twice attempted, but failed, to get a temperature from the molten lava lake. They succeeded, however, in obtaining a large lava sample (shown in photo, with Perret at right) using the cable. To be continued next month ...

Hawaiian volcanoes—This month in history

July 5, 1975 After 25 years of slumber, Mauna Loa woke with a spectacular, but short-lived, eruption that began just before midnight on July 5. Lava fountains soon erupted from fissures extending across the length of Mokuʻāweoweo, Mauna Loa's summit caldera, and into the upper ends of the volcano's northeast and southwest rift zones. After only 6 hours, the caldera and southwest rift zone activity ended, but fountains on the northwest rift zone continued to erupt until 7:30 p.m. on July 6, when all eruptive activity ceased. July 19, 1974 Lava erupted at the summit of Kīlauea for the first time in almost three years on this day. Fissures between Crater Rim Drive and Chain of Craters Road, and within the summit caldera, erupted fountains of lava that cut both roads, partly filled Keanakākoʻi and Lua Manu craters, and covered the south part of the caldera floor. The eruption lasted only three days, but was significant in that it marked the end of the 1969-74 Mauna Ulu eruption on Kīlauea's east rift zone.