On July 11, 1927, fumes issued from the top of the active southwest spatter cone (lower left) within Halema`uma`u Crater as a river of lava spread across the collapsed lava lake surface. Â (Tai Sing Loo photo from the October 1927 HVO Monthly Bulletin)

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

Age-old questions pondered prior to Kilauea Volcano’s 1927 summit eruption: “Is the volcano dead?” “When will it erupt again?”

These questions were among the most frequently asked by Kilauea visitors, according to Ronald M. Wilson in his Hawaiian Volcano Observatory weekly report on June 30, 1927. At the time, Wilson was temporarily in charge of HVO while the director, Thomas A. Jaggar, investigated volcanoes in Alaska.

Kilauea had not erupted since July 1924, so the questions were reasonable, and one of them was easily answered. “The volcano of Kilauea is not dead,” Wilson wrote, noting that the three-year quiet phase was “but part of the cycle of the volcano.”

“The second question,” he acknowledged, “is not so easily disposed of….” But, a week later, it was definitively answered when Kilauea suddenly came to life with little warning. (In hindsight, there were a few precursory signals.)

Shortly before 1:00 a.m. on July 7, 1927, a Volcano House night watchman making his rounds noticed a faint glow at Halema`uma`u Crater. As the glow grew brighter, he awakened hotel guests. The glow was also observed at Kilauea Military Camp and by occupants of the Kilauea Summer Camp cottages. Within minutes, a procession of automobiles was on the road, rushing toward Halema`uma`u.

By 1:40 a.m., a crowd of about 50 people, including Wilson, had reached the crater rim. They watched in awe as four lava fountains up to 38 m (125 ft) high erupted within Halema`uma`u, forming a lava lake that soon covered the crater floor.

Two fountains were on a talus slope on the southwest side of the crater, well above the lava lake. These vents sent rivers of lava 3–6 m (10–20 ft) wide streaming into the lake, estimated to be 9 m (30 ft) deep within the first hour. A third vent at the foot of the talus slope produced a small twin fountain at the edge of the lake.

The fourth fountain erupted from a vent below lake level on the northeast side of the crater. As lava gushed up through the lake, it set in motion waves that crossed the lake’s surface to the opposite side of the crater, providing evidence of the depth and fluidity of the impounded lava.

The lava fountains produced a “thundering roar” so loud that people on the crater rim had to raise their voices to be heard. For the most part, the growing crowd watched the eruption in relative comfort, grateful for the intense heat of lava in the cold, early morning air. But occasionally, whirlwinds carried choking sulfur fumes to the crater’s edge, causing spectators to hastily retreat.

The news quickly spread to Hilo. The road to Kilauea was under construction, but bumps and potholes did not deter people intent on reaching the volcano. As soon as word reached Honolulu, hundreds of residents and visitors hurriedly booked passage on steamships setting sail to Hilo.

Within 24 hours, three of the vents ceased action. One southwest fountain remained active, feeding a voluminous stream of lava into the lake and building a 12-m- (40-ft-) high spatter cone on the talus slope.

Daybreak on July 8 revealed that the lava lake had partly drained during the night, causing the cooled crust to collapse about 3 m (10 ft) and leaving a high lava mark around its edges. Lava from the southwest cone flowed onto the collapsed crust, where it began to spread.

By July 9, the activity was less spectacular, but lava kept erupting from the cone. Lava flows on the crater floor grew in both depth and area and, by July 13, covered most of the collapsed lake surface. Over the next week, the eruption grew weaker, but sluggish flows continued, eventually raising the crater floor by about 24 m (80 ft).

On the morning of July 20, only a small amount of fume issued from the spatter cone, and, by that afternoon, all activity had ceased. The eruption was over.

The questions addressed by Wilson in 1927 could be asked today of Mauna Loa and Hualalai, quiet since 1984 and 1801, respectively, but not dead. Interestingly, Kilauea’s eruption, ongoing since 1983, has resulted in an even more difficult question to answer: “When will it end?”