Impressive lava fountains from the north vent in Halema’uma’u crater during 48 episode (image: HVO/USGS))
A new lava fountaining episode 48 at Halemaʻumaʻu crater began at 4:40 a.m. HST on June 1 and ended abruptly at 1:37 p.m. the same day, lasting just under nine hours. The activity was confined to the north vent, which produced continuous fountaining until the final minute, when it transitioned to gas jetting. The south vent did not generate fountains during this episode, though it intermittently spattered and produced occasional jetting bursts.
The instantaneous effusion rate peaked at roughly 415 cubic yards (320 cubic meters) per second shortly before 6:00 a.m., with an average rate of about 245 cubic yards (185 cubic meters) per second over the full episode. In total, an estimated 7.3 million cubic yards (5.6 million cubic meters) of lava erupted, resurfacing approximately 40% of the Halemaʻumaʻu crater floor. The Uēkahuna tiltmeter (UWD) measured about 17.1 microradians of deflation during the event.
The vigorous north‑vent fountain generated intense heat and ash, feeding a plume that rose to about 25,000 feet (7,600 meters) above sea level, according to radar observations from the National Weather Service and the Washington VAAC. Early in the event, low‑level northeast trade winds carried most tephra southwest of Halemaʻumaʻu. As the plume expanded upward, southerly winds between 10,000 and 20,000 feet began pushing it northward, allowing ash and pumice to disperse around the rim of Kaluapele (Kīlauea caldera).
At 5:31 a.m., the National Weather Service issued an ashfall advisory for southeastern and northeastern areas of Hawaiʻi Island, including Hawaiʻi Volcanoes National Park. Sparse pumice up to 1–2 inches (2–5 cm) in diameter fell at Uēkahuna overlook, Nāmakanipaio campground, and along Highway 11 west to the 34‑mile marker. Fine ash and Peleʻs hair accumulated around Kīlauea Visitor Center and in communities northeast of the caldera—Mauna Loa Estates, ʻŌhia Estates, and Volcano Village—as well as west of the caldera between mile markers 34 and 36. Very light ashfall was reported as far away as Mountain View. A commercial pilot also reported a sulfur‑and‑ash cloud near Laupāhoehoe, prompting several morning flight cancellations and diversions to Hilo.
A small earthquake swarm on the southwest side of Halemaʻumaʻu began around 12:15 p.m., shortly before the episode ended, and continued sporadically for several hours afterward. About 15 earthquakes were large enough to locate, ranging from just under magnitude 1 to magnitude 2.2. Three events were magnitude 2 or greater, eight were between magnitude 1 and 2, and four were below magnitude 1. These earthquakes had no observable effect on the eruption or the crater.
Source: USGS Hawaiian Volcano Observatory volcano activity update 2 June 2026
