Lua Manu Crater is the first
pit crater on Chain of Craters Road. In 1974, the crater was
partial filled by lava erupted from a fissure about 600 feet
northwest of the road. Pit craters are the most common feature
along the upper East Rift Zone of Kilauea. There have been no
historic eruptions at Puhimau and Kokoolau, the next two pit
craters on Chain of Craters Road.
 Chain
of Craters Road intersects with Hilina
Pali Road about 2 miles down from
the turn off of Crater Rim Drive. Hilina Pali Road is 7 miles
long and leads to Hilina Pali Overlook which is well worth a
visit.
On March 3, 1992, in
the early morning hours, a body of magma migrated in the East
Rift Zone, a weak area in the flank of the volcano. Volcanologists
call such a body of magma an intrusion or a dike. As the magma
forced its way through the rift, it generated a swarm of over
2000 small earthquakes, most of which were too small to be felt.
However, a few of the earthquakes were large enough (about magnitude
4) to wake residents in nearby Volcano Village. The magma moved
from a depth of about 2-3 miles up to 0.5-1 miles. The magma
acted like a wedge within the volcano, cracking the rocks and
driving them apart. The volcano is actually spreading laterally
because of the cumulative force of numerous intrusions of magma
into the rift. The March 3 intrusion caused brittle rocks at
the surface to crack. A crack also extended across Chain of
Craters Road, closing the road for about one day. The magma
never reached the surface to generate an eruption. Only about
half of the magma supplied to Hawaiian volcanoes ends up being
erupted. The rest of the magma stays inside the volcano, increasing
its size from within.
 Hiiaka
pit crater is in the east side of a larger collapse basin. The
crater is about 300 feet deep and 1,200 feet wide. Fissure eruptions
in 1968 and 1973 produced lava flows in and around Hiiaka Crater.
The 1968 eruption lasted less than one day and formed a small
lava pond on the crater floor. The 1973 eruption also lasted
less than one day but was far more dramatic. Fissures opened
on the south side of the crater floor, in the collapse basin,
and just outside of the crater. (See the diagram below, referenced
with photo above, for a detailed view).
Just south and west of Hiiaka
Crater is the Koae fault system. The faults extend from the
East Rift Zone to the Southwest Rift Zone, a distance of 7.5
miles. The faults are less than 500-750 years old. Unlike most
faults on Kilauea, which face to the south, faults of the Koae
system face to the north. Some geologists think the faults are
related to an older caldera. (See diagram below for more information).
The Koae fault system serves
as a topographic barrier to the lava flows that originate near
the summit of Kilauea. A large bite in the coast line of Kilauea
volcano is a result of the lack of lava flows in this area.
Before lava flows can move down onto the south flank they must
fill the low area north of the fault to a depth of about 50
feet. This is an excellent example of how topography can influence
is distribution of lava flows.
 Pauahi
Crater consists of three overlapping prehistoric pit craters.
These pit craters cut across prehistoric lava flows and ash
layers roughly 350-500 years old. Most of the pit craters along
the East Rift Zone have complex histories which include multiple
collapse events. Three eruptions have occurred near Pauahi Crater
in historical time. Below a detailed diagram provides
more detail.
The November 1973 eruption
lasted a total of 31 days but most of the activity was during
the first 10 hours of the first day. A set of echelon fissures
extended from just west of the crater, across the crater floor,
and east of the crater almost to Puu Huluhulu, a total distance
of about 2 miles. Lava from some of the fissures cascaded 300
feet to the floor of the crater. The fissures and cascades supplied
lava to two growing lava lakes.
 After
the initial flurry of activity, a single vent in the western
pit crater continued to erupt. Lava in the central pit had drained,
leaving behind a "bath tub ring" that marked the high stand
of the lake.
Just down Chain of Craters
Road from Hiiaka & Pauahi the landscape begins to change. Pit
craters and continuous tracts of rainforest give way to a single
shield-shaped vent on the horizon called Mauna Ulu (growing
mountain), kipukas, and lava flows that extend to the ocean.
A short side road leads to
the Napau Crater trail, the walk to Puu Huluhulu, a view of
1974 lava flows that buried an older Chain of Craters Road,
and Mauna Ulu. This side road was once Chain of Craters Road
and lead to Makaopuhi Crater and then down to the coast.
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