(BIVN) – Things have gone relatively quiet at Kīlauea volcano, where just a few hours earlier on Monday, dramatic lava fountains were bursting high into the air from a vent on the crater wall.
The eruptive vent on the southwest side of the summit crater had been putting on a show for the last several days, and the height of the fountain appeared to be getting higher throughout the day. On the USGS webcam, viewers watched live as the spatter cone surrounding the vent periodically collapsed into the churning lava.
But then, there was an abrupt change. By 4 p.m., the activity at the vent had diminished to a mere trickle of lava, and some minor spattering at the top of the cone.
And by 6 p.m., just before sunset, the vent appeared to be completely quiet.
The Hawaiian Volcano Observatory has been tracking steady deflationary tilt in the summit area since Saturday morning, however this graph shows a switch to inflation at around the time the active vent went quiet. What this means for the current eruption of Kīlauea remains to be seen. For now, the Kilauea alert level remains at WATCH, and the aviation color code remains at ORANGE.
UPDATE – (10:30 p.m.) – The USGS Hawaiian Volcano Observatory issued a Kīlauea statue report on Monday evening, saying the summit eruption at Kīlauea volcano has paused. From the USGS HVO:
Halemaʻumaʻu Observations: This afternoon around 4:00 p.m. there was a rapid decline in lava fountaining and effusion at the eruptive vent on the southwest side of Halemaʻumaʻu crater. Vent activity had been vigorous up to that point in the day. Circulation of the southwestern lava lake slowed thereafter, and the lake’s surface dropped by several meters. Some previously erupted lava continues to flow on the crater floor; this may continue over the coming hours and days while the lava proceeds to cool. A live-stream video of the crater is available (here).
Summit Observations: Simultaneous with the decline in vent activity, seismic tremor—a signal resulting from subsurface fluid movement, and commonly associated with eruptive activity—started dropping around 4:00 p.m. Also, tiltmeters in the summit region detected a quick transition to inflationary tilt after tracking steady deflationary tilt since the morning of Saturday, June 17.
Rift Zone Observations: No unusual activity has been noted along the East Rift Zone or Southwest Rift Zone; steady but low rates of ground deformation and seismicity continue along both. Measurements from continuous gas monitoring stations in the middle East Rift Zone—the site of 1983–2018 eruptive activity—remain below detection limits for SO2.
Hazard Analysis: The eruption at Kīlauea’s summit is occurring within a closed area of Hawai’i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are the primary hazard of concern, as this hazard can have far-reaching effects down-wind. As SO2 is continuously released from the summit during the eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. Vog information can be found at (here).
Additional hazards include Pele’s hair and other lightweight volcanic glass fragments from the lava fountains that will fall downwind of the fissure vents and dust the ground within a few hundred meters (yards) of the vent (s). Strong winds may waft lighter particles to greater distances. Residents and visitors should minimize exposure to these volcanic particles, which can cause skin and eye irritation.
Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.
The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea volcano.