🚀 go-pugleaf

"Pau hana time" is s popular local phrase.  Pau means stop, hana means
work.  Pau hana time is when you quit work.

Although there are lots of uncertainties in predicting what a volcano
will do, it is beginning to look like the five-year-old eruption of
Kilauea volcano may be coming to an end, based upon some significant
changes in the last couple of days.

To recap:  the current eruption began 3 Jan 1983.  The initial phase
was near Napau Crater inside the Hawaii Volcanoes National Park, but
within a few hours had moved on to a site on Campbell Estate land where
it eventually built a cinder cone later named Pu'u 'O'o (literally:
the hill of O and O, a play on the first letters of the names of
a couple of scientists at the USGS Hawaii Volcano Observatory).
Early stages over the first year or so featured some very spectacular
lava fountains ranging from 300 to 1,000 feet high.  On 18 July,
after 47 phases of periodic high fountaining, the eruption site moved
further down the rift zone on the flank of Kilauea to what was later
named the Kupaianaha lava pond and began a steady outpouring of
4.9 cubic meters per second (about 500,000 cubic meters per day...enough
to since then have paved a multi-lane highway 1 foot thick from here
to the Moon).  Lava, first on the surface, then through a series of
lava tubes, flowed down the mountain to the sea, creating some spectacular
results there, including some extensive black sand beaches.

The first hint of a radical change came Sunday afternoon when a helicopter
pilot noted that the level of the Kupaianaha lava pond had dropped
from its previous level of 50 feet below the rim to about 100 feet below.
On Monday, another pilot discovered the level of the pond had dropped
further, to about 200 feet.  A drop like this hasn't been seen since the
pond started forming.  The low levels meant that no new magma was entering
the pond from deep within the earth.  Meanwhile, lava continued its normal
process of draining out of the pond through an opening in its southern end.
Through that opening, the lava enters a system of subserface tubes that
carries it seven miles to the sea coast around Kupapau Point on the Puna
coast.

By late Monday, the lava flowing downhill in those tubes had drained out,
and lava was no longer entering the sea.

So, at the moment, it looks like the eruption may have come to a halt.

However, some indications of deeper underground activity remain.  The
"hot spot" which feeds Kilauea lies about 40 miles deep.  From there,
magma rises to a large temporary storage chamber about 1.5 miles below
Kilauea's summit. From there, it can go to various places; years ago it
regularly fed the Halemaumau fire pit in the caldera at the summit; in
recent years, other "plumbing" has been feeding the series of eruptions
(including this last one) along one or more of Kialuea's rift zones
along major ridges of the mountain.  Movement of lava the hot spot into
the storage chamber can be "heard" via "harmonic tremor" readings
on the observatory's seismometers.  They the harmonic tremor is still
there, but has substantially decreased in amplitude to only about 30
percent of normal. This means that magma is still accumulating in the
storage chamber and may flow out to the surface again, either at or near
the lava pond site, or elsewhere on Kilauea.  Tiltmeter measurements
over the last few months indicate a gradual swelling of the summit
of Kilauea, which presumably means that there is a considerable amount
of magma in the storage chamber.

At this point, one of three things may happen:  harmonic tremor will
continue to decrease, and tiltmeter readings will remain fairly steady,
and 1) there might not be a further eruption...or, it is possible we
may see some 2) brief renewal of activity, then no further activity for
a year or more.  Alternatively, if harmonic tremor comes back up to
previous levels, we may see 3) a renewed sustained eruption, possibly
some place else on Kilauea.

No one knows for sure, but this just might be the end of the eruption.
Bob Cunningham
bob@loihi.hig.hawaii.edu