(BIVN) – The summit of Kīlauea volcano was quiet as Monday began, as Episode 18 in the ongoing eruption within Halemaʻumaʻu continues in cyclic fashion. The USGS Volcano Alert Level for Kīlauea remains at WATCH.

The most recent update from the USGS Hawaiian Volcano Observatory reports “lava stopped erupting from the south vent at 12:44 p.m. HST” on Sunday, which ended the fourth cycle of the episode.

“The length of the eruptive cycles continues to get shorter and the pauses in between them continue to increase in duration,” the scientists noted.

From the USGS HVO analysis posted on Sunday morning:

The current eruption has been characterized by episodic fountaining not seen in any of the other Halemaʻumaʻu eruptions since 2020. Fountains and lava flows have erupted from two vents that we refer to as the north vent and south vent. Each of the previous 17 fountaining episodes lasted from a few hours to over a week and have been accompanied by strong deflation of the summit region. Pauses between the fountaining episodes have been marked by an immediate change from deflation to inflation as the magma chamber recharges and repressurizes.

Analysis of inflationary tilt patterns prior to the onset of each fountaining episode allows a time window of probability for the onset of new episodes to be estimated. These are calculated using both minimum inflation necessary to start a new eruption and the rate of inflation fit to data derived from past eruptive episodes. The precursory activity of episode 18 occurred as forecast on Wednesday April 16 when inflation slightly exceed episode 17, but was followed by continued inflation. The extended time gap between the precursory eruptive activity starting episode 18 and the onset of fountaining differs from the other episodes. This may be related to the early onset of episode 17. Inflation continued until today April 20, when it reached levels seen during episode 16. Eruption of degassed lava from the vent began at 7:45 a.m. HST and is continuing. Based upon prior cycles of fountaining and deflation, episode 18 fountaining is likely to be less than 24 hours long.