The erupting fissure stretched for nearly a mile across the down dropped block. This block is an enourmous slab of the old caldera floor, a mile across and wide, it had slumped down hundreds of feet during the 2018 Kilauea caldera collapse.
USGS reports had dubbed this slab the “down-dropped block” where it is routinely referred to in the daily reports of eruptive activity. The lower western edge had succumbed to the lava lake slowly filling the lower sections of the collapse pit where the edge of the block had become flooded by the growing lava lake.
This block had slumped down nearly intact, the top still flat, if now somewhat tilted to the west. The old features atop this block still visible including pahoehoe flows, old eruptive vents, and the hiking trail I had once hiked in crossing the caldera floor.
The old Halemaʻumaʻu Trail could still be seen as a lighter path beaten across the black lava by thousands of hiking boots. The trailhead was at the Halemaʻumaʻu parking lot, the pavement of that lot and sections of Crater Rim Drive still visible on smaller slump blocks on the west side of the caldera, also hundreds of feet below the original caldera floor.
The September 2023 eruption started as a fissure right across the down dropped block. For almost a mile fountains of lava surged and frothed. The down dropped block completely bisected by the eruption.
One small vent marked the end of the fissure, right at the eastern end where lava had forced its way through the pile of debris at the cliff that marked the block’s edge. Overlooked by most with far more spectacular fountains to be enjoyed. I found that last little vent fascinating where lava tumbled down through the talus.
I have not had a chance to look again, but I suspect this eruption finally covered over much of that section of the hiking trail. I wonder, one day when the caldera floor is filled by this series of eruptions if there will once again be trails out to cross the caldera, and if I will still be around to hike them.
Yes, she is rumbling again, mere weeks after the last eruption ended.
Inflation at the summit has surged with a vengence, the pressure under the caldera right back to where it was at the start of the September eruption. A persistent pattern of earthquakes rumbles beneath the southwestern flank indicating intruding magma.
The USGS has noticed, they are back to issuing daily reports. The park service has noticed, trails in the southwestern rift zone have been closed. Local photographers have noticed, plans are ready to spring into action with grab-and-go bags of photo gear by the door.
The Kilauea eruption that started one week ago today is pau. To translate that from Hawaiian to English… Done.
The eruption had notably waned over the last couple days, comments on social media and webcam video indicating sluggish spatter within the small cones that had built up over the last week around the fissures. Last night numerous small bits of glow were visible all across the crater floor, but no fountaining was in evidence.
Today’s USGS Volcano Observatory report is clear… “The Kīlauea summit eruption that began on September 10th stopped yesterday, September 16th, and is unlikely to restart.”
So we wait for the next one, any bets?
My Facebook post describing a last moment mission to the volcano caught the attention of one of our local reporters. Result? An interview and a little piece about volcano viewing carried on several of the local media outlets. Nothing serious, they are just trying to capture the event of the moment and the local response. Perhaps something positive in the face of all the tragic fallout from the Lahaina disaster that fills the local news. Not my first time in the news, but the first time in a while, it is always fun…
Watching the recent and repeated eruptions in the Kilauea caldera has made an interesting bit of info clear… The first few hours are the most spectacular.
Months of inflation Kilauea had stored large quanities of gas and built up a considerable amount of pressure, enough pressure to lift the megatons of rock above the magma chamber and cause the entire summit region to swell outwards.
Beween eruptions USGS geologists and armchair vulcanologists like myself keep an eye on the tiltmeters as the pressure in the volcano builds, awaiting the time that accumulating magma and increased pressure bursts through the overlying rock to begin a new eruptive cycle.
At 15:13 HST Sunday afternoon that moment came.Continue reading “The First Few Hours”