USGS: “A helicopter overflight on September 20, 2024, allowed for aerial visual and thermal imagery to be collected at the middle East Rift Zone eruption site on Kīlauea. This thermal map shows that the eruption at Nāpau Crater had paused this morning, with no fountaining or active lava on the surface. Shortly after these morning thermal images were collected, a small portion of the fissure system briefly reactivated, but soon died out again. As of this afternoon, the eruption was again in a pause. The scale of the thermal map ranges from blue to red, with blue colors indicative of cooler temperatures and red colors indicative of warmer temperatures.”

(BIVN) – The eruption of Kīlauea on the middle East Rift Zone (MERZ) remains paused as of late Saturday evening, and the USGS Volcano Alert Level has been maintained at WATCH. 

The USGS Hawaiian Volcano Observatory noted in its daily update that minor glow continues at night from the vent and small spots on the flows, been has greatly diminished. Degassing from the vent continued with a gas plume moving to the southwest on Saturday morning. 

“The fourth phase of activity in ongoing MERZ eruption appears to be over,” wrote scientists in a Saturday analysis. “The current eruptive activity appears to be linked to the continuing supply of magma from the summit.  The supply rate appears to have diminished slightly over the past several days from rates at the eruption onset. However, the storage areas in the MERZ continue to pressurize and another eruptive phase in this area is a possibility.”

In Hawaiʻi Volcanoes National Park, the Maunaulu Trail and parking area remain closed due to eruption-related hazards, as well as the Nāpau Trail and Nāulu Trail. Escape Road is open from Highway 11 to the Maunaulu access road closure.

USGS: “On September 20, 2024, USGS Hawaiian Volcano Observatory geologists examined a ground crack near the recent eruption site in the remote middle East Rift Zone of Kīlauea.” (USGS photo by M. Patrick)

From the Saturday update by the USGS HVO:

Summit Observations:  Nine small, shallow earthquakes were detected beneath the Kīlauea summit region over the past 24 hours. The tiltmeter at Uēkahuna remains flat or showing slight inflation. The summit tiltmeter at Sandhill continues to record deflation, but at a decreased rate compared to the onset of the eruption on September 16. This pattern suggests that only the deeper, southern summit magma body is continuing to supply magma to the middle East Rift Zone. The most recent measurement of SO2 emission rate at the summit was 60 tonnes per day on September 17, 2024. 

Rift Zone Observations: The eruption near Nāpau Crater remains paused since yesterday morning. Glow from the vent continued overnight and degassing remains fairly vigorous. The gas plume is currently moving southwest from the vent due to normal trade winds. Lava flows from this eruption have covered about 2/3 (500,000 square meters or 125 acres) of the floor of Nāpau Crater. In total, this eruption has covered more than 630,000 square meters (156 acres) of Nāpau Crater and areas to the west since Sunday night. Approximate effusion rates of roughly 5-15 cubic meters per second (6-16 cubic yards) were estimated during the most active part of the fissure eruption on September 19.

Shallow earthquake counts remain very low in the MERZ with about 8 in the past 24 hours. Little or no tremor is being recorded on the MERZ seismometers close to the eruption site. Tiltmeters in the MERZ continue to show no significant shallow deformation, but GPS instruments continue to show inflation at deeper levels beneath the area between Maunaulu and Nāpau Crater.

Sulfur Dioxide (SO2) emission rates measured on September 19, were 30,000 tonnes per day for during the onset of the fourth eruptive phase.

All activity is currently confined to the middle East Rift Zone between Makaopuhi Crater and Puʻuʻōʻō and there are no indications of any changes further downrift in the MERZ or in the LERZ.