Volcano Watch: What is the highest elevation reached by Halemaʻumaʻu lava on Kīlauea?
The 2018 collapse of southern Kaluapele (Kīlauea caldera) left a pit whose lowest point was about 1640 feet above sea level.
Since 2020, that pit has filled to a little more than 2,950 feet above sea level. One might wonder: How high the lava level could go?
We can’t answer that question but we can get an idea by looking to Kīlauea’s past.
The history of Kaluapele is a collection of periods of rising lava level within Halemaʻumaʻu, often to the point of overflowing, followed by abrupt and rapid drops in the level. After some time, the sequence repeats, rising to a slightly higher level.
The process resembles a “two steps forward, one step back” sequence, with slowly rising lava level peaks.
The highest level of lava in the past two centuries was reached in the first few months of 1894, during years of repeat surveys by the Hawaiian Government. Rapid drops of the lava level occurred on March 6, 1886, and again exactly five years later on March 6, 1891. The final rapid drop of the 19th century began on July 11, 1894.
Frank Dodge, a surveyor with the Hawaiian Government Survey, mapped Halemaʻumaʻu in August 1892 and March 1894. The 1892 survey showed a lava lake 240 feet below the rim of Halemaʻumaʻu pit and 522 feet below the Volcano House veranda on the northeast rim of the caldera (elevation 4,040 feet), then located about 490 feet northwest of the current hotel.
Elevations were measured multiple times with a surveyor’s theodolite to assure the highest accuracy possible. The lava level elevation was 3,518 feet in August 1892.
The lava level continued to rise and, in the first months of 1894, visitors and residents found that lava frequently overflowed from Halemaʻumaʻu onto the caldera floor. They also noted that the pit crater was filled, and the lava lake was “on top of a nearly circular cone” or hill.
Dodge completed a follow-up map on March 20, 1894, confirming the filling of Halemaʻumaʻu pit and the rising of the lava lake above the 1891 pit rims. The lava lake was about 15 acres in area atop a low shield on the caldera floor. Instead of multiple measures of elevation below the Volcano House, he only made one.
The 1894 map was excellent; but Dodge’s quick measurement of the lava lake elevation relative to the Volcano House may have been wrong. After completing the map in 1894, he stated that the lava level rose “447 feet in 19 months” since 1892; but in 1904, he began to doubt that measurement and he added a note in the margin of this map saying that the 447 feet change may be too high.
Dartmouth Professor emeritus C.H. Hitchcock suggested a compromise: assume that, in March 1894, Halemaʻumaʻu was filled to the 1892 brim so the lava level rose by only 240 feet between surveys. This ignored multiple reports and Dodge’s map of the lava lake being above the earlier rims.
Dodge responded that he could not accept Hitchcock’s suggested solution.
“The height of the lava at the ‘supreme moment for Halemaumau’ will never be positively known…It was somewhere between the -75′ and -282′, referred to the Volcano House datum.”
In addition to the map, Dodge also drew August 1892 and March 1894 cross-sections of the Halemaʻumaʻu pit at the same scale. If we ignore the questionable datum line on the 1894 cross-section and overlay on the 1892 cross-section by matching slopes outside the pit, we can graphically estimate the highest elevation.
This simple exercise shows that the March 1894 lake must have been at least 100 feet above the 1892 brim. This all-time peak elevation was a minimum of 180 ft below the Volcano House veranda or 3,860 feet above sea level.
For perspective, the 2008–2018 12-acre lava lake rose to 3,392 feet just before its final drop during the 2018 summit collapse. The 2018 Halemaʻumaʻu pit crater (370 acres) is currently filled to about 3,020 feet.
We have a long way to go to reach a new “supreme moment” for Halemaʻumaʻu.
Editorʻs Note: Volcano Watch is a weekly article and activity update written by scientists and affiliates with the U.S. Geological Survey Hawaiian Volcano Observatory.