(BIVN) – Low-level lava activity continues at the summit of Kīlauea, where the summit eruption is ongoing, and may or may not be building to another episode of high fountaining.
The USGS Hawaiian Volcano Observatory says episode 55 fountaining remains a possibility. Scientists repeated on Wednesday that “it is not possible to say with certainty that this activity will lead to the onset of another fountain event at this time, although conditions remain favorable.”
Intermittent lava overflows and spatter from are occurring at both north and south vents in Halemaʻumaʻu, while the west vent had occasional glow overnight. There is no anomalous activity outside of the summit along Kīlauea’s East Rift Zone or Southwest Rift Zone.
From the USGS HVO on Wednesday:
Summit Observations:
Overflows from the north vent resumed on the evening of September 22 after about 10 days of quiescence at the vent complex. Overflow activity from the south vent began on September 27. However, the north vent remained dominant until the evening of September 28, when south vent started having short, rapid cycles of overflows and lava drainback that continued through yesterday afternoon. These south vent overflows lasted about 2–5 minutes, with most pauses between each cycle lasting about 5–7 minutes; there were over 100 such overflows. Since yesterday afternoon the frequency of overflow activity has greatly decreased, although intermittent overflows continue at both north and south vents. Since this morning, north vent has had several short-lived overflows with minor dome fountaining. Both north and south vents also spattered overnight and had persistent strong glow, and west vent had occasional glow. No other areas of incandescence were observed across the summit region last night.
Continuous tremor is the dominant seismic signal across the summit. There were 20 small and shallow earthquakes located across the summit region in the past day, including a cluster south of Halema’uma’u.
Summit tiltmeters have recorded minor inflation over the past 24 hours. The Uēkahuna tiltmeter (UWD) recorded approximately 0.8 microradians of inflation. The current total inflation since the end of episode 54 is about 17.4 microradians, which is nearly 5 microradians greater than what was lost during episode 54 fountaining.
During inter-episode pauses, the sulfur dioxide (SO2) emission rate from the summit typically varies between 1,000 and 5,000 tonnes per day. Winds are currently forecast from the southeast.
Rift Zone Observations:
Rates of seismicity and ground deformation remain low in the East Rift Zone and Southwest Rift Zone. SO2 emissions from the East Rift Zone remain below the detection limit. No significant ground deformation was recorded in either rift zone.
Analysis:
The north vent resumed overflow activity on September 22. The south vent resumed overflow activity on September 27. The north and south vents continued to have intermittent overflows and spatter, strong glow and emitted flames overnight. Strong continuous tremor dominates the seismic signal within the summit. Forecast windows for a potential episode 55 can no longer be modeled due to the irregular changes in inflation and deflation. Summit tiltmeters recorded net inflation in the past 24 hours, and since the end of episode 54 the total inflation is nearly 5 microradians more than what was lost during episode 54. The north vent has produced the last 11 high fountain events (episodes 44–54). It is not possible to say with certainty that this activity will lead to the onset of another fountain event at this time, although conditions remain favorable.
Because the summit system remains active and highly pressurized, the two most likely possibilities are that activity continues at the north-south-west vent complex, or it activates another existing weak crack system in the summit region. Neither of these events are likely to produce a strong seismic precursor, so the alert levels have been left at ORANGE/WATCH as the volcano continues to “exhibit heightened unrest with an increased potential for eruption”.
