53 Hour Gap in Summit Collapse Activity: What Does it Mean?

Earthquakes shook the ground at Kīlauea’s summit late Wednesday afternoon, July 25, 2018, stirring up rock dust within Halema‘uma‘u and along the caldera walls. This view from the northeast caldera rim looks across at the Keanakāko‘i and South Sulphur Banks areas. PC: USGS 7.25.18

The Hawaiian Volcano Observatory reports that an explosive collapse event at Kīlauea summit occurred at 12:09 p.m. today, Thursday, July 26, 2018.

This marks 53 hours since the last collapse event occurred on Tuesday, July 24, 2018 at 6:41 a.m. It is the longest gap in intervals in collapse activity since May.

There was no tsunami generated from the seismic event that released energy equivalent to a 5.4 earthquake, according to the Pacific Tsunami Warning Center.

When asked about the reason for the gap, authorities with the Hawaiian Volcano Observatory say it’s too early to tell, but there’s a possibility that it could reflect a decrease in the occurrence of these types of events.

“For now, there is some variability in how frequently these event occur, and this was outside of the typical range. I think we really have to look for a couple more to see if this timing continues to lengthen and activity decreases, or if we end up as frequent as we were in the past,” said Ingrid Johanson, Research Geophysicist with the USGS Hawaiian Volcano Observatory, during a press briefing this afternoon.

Leslie Gordon, USGS Public Information Officer (Western States Communications) also weighed in saying, “Our assumption is, as long as lava continues to erupt on the Lower East Rift Zone, that there’s a likelihood of continued summit collapse.  I think that the length of the interval between the last one and today’s event, that could be an anomaly, but as Ingrid said, it’s too early to say.”

Gordon suggested that scientists need to wait and see how the next collapses occur, to determine if those intervals between collapses is indeed increasing, or if this is just an anomaly. “It has varied from the beginning,” said Gordon.

Today’s collapse marked number 58 since the onset of the current eruption in May.  ” It’s approaching 60.  There have been variations in the intervals in the collapse events.  Right now, we’re waiting and watching to see what happens in the coming days,” said Gordon.