The dramatic opening of the Overlook crater within Halemaumau Crater on March 19, 2008, heralded a new period of activity for long time Kilauea Volcano watchers.
Over the next several years, nearly continuous eruptive activity formed an active lava lake in the new crater. An active lava lake is one that overlies its vent, which constantly supplies lava to the lake and drains lava from the lake. This circulation keeps lava in the lake hot and also generally keeps it from spilling from the crater. An active lava lake contrasts with a “passive” lava lake, which is simply a pool of lava formed when lava flows into a depression.
The active lava lake in Overlook crater is now the second largest lava lake on Earth, about 560 feet by 720 feet across. The lake is more than 328 feet deep and Overlook crater itself deepened by26 feet in late April and early May 2015, when overflows onto the floor of Halemaumau built the rim higher.
Visitors to the summit of Kilauea are now accustomed to the spectacular nighttime glow above the lake as it rises and falls in concert with summit inflation and deflation, as well as with expansion and episodic escape of gas bubbles.
Although relatively new to most of us, churning lava lakes are certainly not new to Halemaumau Crater. Indeed, from 1823 through 1924, a lava lake (or lakes) was nearly always present in the caldera, generally inside Halemaumau. Short-lived lava lakes played in Halemaumau several times between 1924 and 1968. Much of the time, however, visitors witnessed a scene quite different from today.
As one example, this nearly century-old print shows Halemaumau when much more of its floor was covered by a lava lake compared to today. Towering bodies of solidified lava called “crags” rise above the lake surface like battleships on the sea. At times these crags were so high that they could be seen by spectators at the old Volcano House nearly 2 miles away. Visitors could sometimes view lava fountaining and hear noises of splashing lava from the hotel. Today, the clatter of breaking and falling rocks is, with favorable wind, audible outside Jaggar Museum, and the overflows in April and May were visible from many caldera vantage points.
In the early 1900s, the lava lake inside Halemaumau resembled a dynamic body of water in many ways. Thomas A. Jaggar, founder of the Hawaiian Volcano Observatory, used terms such as cove, bay and inlet to describe lava pools and other features in the lake. The lava lake was typically impounded by levees made by overflows of lava from the lake, just as overflows of silt-laden water create levees along the Mississippi River.
This photograph shows what was known as the Southeast Crag, a 36-foot-high peak of solidified lava that had been twisted and tilted upward. As of yet, we’ve not seen any similar features developed in the current lava lake within Overlook crater. This may be because the present lake is impounded by the walls of Overlook crater, not by its own natural levees, which can change configuration and location with time. If such self-impoundment should develop in the Overlook lava lake, we may once again see crags, bays and inlets.
We will share more of the rich photographic record of Halemaumau lava lakes from the last century in future Volcano Watch columns. Although they lack the vivid and mesmerizing colors of modern photographs, there is a stark beauty in these crisp, black and white scenes of lava in its myriad forms that we find equally compelling.
Kilauea activity update
Kilauea’s summit lava lake level fluctuated over the past week with changes in summit inflation and deflation, but remained well below the rim of the Overlook crater. During the past week the lake ranged between 130 and 210 feet below the current floor of Halemaumau.
Kilauea’s East Rift Zone lava flow continues to feed widespread breakouts northeast of Puu Oo. Active flows remain within about 5 miles of Puu Oo.
One felt earthquake was reported on Hawaii Island. On June 12 at 1:07 p.m., a magnitude-2.3 earthquake occurred 5 miles east of Waimea at a depth of 8.1 miles.
Visit the HVO website at www.hvo.wr.usgs.gov for Kilauea daily eruption updates and other volcano status reports, current volcano photos, recent earthquakes and more; call 967-8862 for a Kilauea summary update; email questions to askHVO@usgs.gov.
Volcano Watch is a weekly article and activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.