RESEARCH ARTICLE
◥VOLCANOLOGY
Cyclic lava effusion during the 2018 eruption
of Kīlauea Volcano
M. R. Patrick^1 *, H. R. Dietterich^2 ,J.J.Lyons^2 , A. K. Diefenbach^3 , C. Parcheta^1 , K. R. Anderson^4 ,
A. Namiki^5 , I. Sumita^6 , B. Shiro^1 , J. P. Kauahikaua^1
Lava flows present a recurring threat to communities on active volcanoes, and volumetric eruption rate
is one of the primary factors controlling flow behavior and hazard. The time scales and driving forces
of eruption rate variability, however, remain poorly understood. In 2018, a highly destructive eruption
occurred on the lower flank of Kīlauea Volcano, Hawai‘i, where the primary vent exhibited substantial
cyclic eruption rates on both short (minutes) and long (tens of hours) time scales. We used
multiparameter data to show that the short cycles were driven by shallow outgassing, whereas longer
cycles were pressure-driven surges in magma supply triggered by summit caldera collapse events
40 kilometers upslope. The results provide a clear link between eruption rate fluctuations and their
driving processes in the magmatic system.
N
umerous communities have been de-
stroyedorthreatenedbylavaflowsin
recent decades ( 1 – 3 ), with recurring crises
at volcanoes around the world, such as
Nyiragongo (Democratic Republic of the
Congo) ( 4 ), Piton de la Fournaise (Reunion
Island) ( 5 ), and Etna (Sicily) ( 6 , 7 ). Another
recent episode of destruction occurred with
the 2014–2015 eruption of Fogo (Cape Verde),
leaving ~1000 people homeless ( 3 ). At Kīlauea
(Hawai‘i), the 2018 eruption produced de-
structive lava flows ( 8 )andthe2014– 2015
crisis disrupted the lives of thousands of
residents when lava stalled just short of de-
stroying the town of Pāhoa ( 9 ). The Pāhoa
crisis was just one episode of Kīlauea’slong-
lived Pu‘u‘Ō‘ōeruptions (1983 to 2018), which
destroyed the town of Kalapana ( 10 ). Risk
mitigation in such crises may include evacu-
ation of residents, removal of property, reloca-
tion of critical infrastructure, or lava diversion
in some cases ( 1 ). The success of this type of
hazard response depends in large part on lava
flow forecasting accuracy ( 9 , 11 ).
The volumetric eruption rate (effusion rate)
is a primary factor controlling the advance rate,
length, and coverage of lava flows ( 12 , 13 ). Effu-
sion rate is an important input into quantita-
tive models that can then be used to forecast
advance rates and areal coverage ( 14 , 15 ). Most
established relationships between effusion rate
and flow behavior, however, are based on
steady-state or time-averaged rates ( 13 ). Our
understanding of effusion rate controls on
flow behavior is challenged by large fluctua-
tions in the rate ( 16 ). Furthermore, the time
scales and driving forces of the effusion rate
variability remain poorly understood ( 13 ). De-
termining whether these variations are deeply
sourced(e.g.,magmasupplyratechanges),
shallowly rooted (e.g., outgassing or com-
positional changes), or result from surface
processes (e.g., lava channel blockage) is
often difficult ( 17 – 19 ).
Kīlauea Volcano has long been a focus
for understanding lava flow behavior and
hazardsbecauseofitshistoryofsustained
lava effusion ( 20 ). On 3 May 2018, eruptive
activity began in the lower East Rift Zone
(LERZ) (Fig. 1, A and B), ushering in the most
destructive phase of volcanic activity in Hawai‘i
in the past 200 years ( 8 ). The main flow,
erupted from fissure 8, was exceptionally well
monitored ( 8 , 21 ). The robust observational
dataset and accompanying geophysical sig-
nals captured cyclic fluctuations in lava erup-
tion rate. This provided an opportunity to
unravel the causative processes and their
hazard implications.The 2018 eruption of K ̄lauea Volcanoı
Kīlauea erupted nearly continuously from 1983
to 2018 from vents on and near the Pu‘u‘Ō‘ō
cone, on the volcano’smiddleERZ( 10 , 22 , 23 ).
Lava flows, predominantly slow-moving, tube-
fed pāhoehoe, covered 144 km^2 of land (Fig. 1A),
with typical recent effusion rates of 2 to 6 m^3 s−^1
( 24 , 25 ). The eruption destroyed 215 structures
( 23 ). As the Pu‘u‘Ō‘ōeruption continued on
the ERZ, a new vent opened at Kīlauea’s
summit in 2008 and persisted for the next10 years, supplying a large, convecting lava
lake ( 26 , 27 ). This joint activity marked the first
time in the 200-year historical record that
prolonged (>1 year) eruptions were concurrent
on Kīlauea’s summit and rift zone ( 27 ).
In March 2018, Kīlauea’smagmaticsystem
began to pressurize at a relatively high rate
( 8 ). Inflation was present at the summit and
Pu‘u‘Ō‘ō,aswellasalongthe20-km-long
ERZ conduit that connects these two erup-
tion sites. Although similar previous episodes
of inflation created new vents on or near
Pu‘u‘Ō‘ō( 9 , 23 ), the 2018 sequence culmi-
nated in an intrusion beginning on April 30
that propagated down-rift (east) from Pu‘u
‘Ō‘ōinto the volcano’s LERZ (Fig. 1A) and
terminated the 35-year eruption at Pu‘u‘Ō‘ō.
The intrusion reached the surface and lava
began erupting from new fissures in the
Leilani Estates subdivision on May 3 (Fig. 1B).
On May 27, activity focused on fissure 8, and
lava advanced 13 km in 6 days to reach the
ocean (Fig. 1, B and C). Fissure 8 continued
as the dominant vent for the next 2 months.
Preliminary estimates of effusion rate from
the fissure 8 vent were in the range of 100 to
300 m^3 s−^1 (dense-rock volume, with bubbles
removed) ( 28 ), far surpassing the typical erup-
tion rates of the previous several decades at
Pu‘u‘Ō‘ō. By the end of major effusion in early
August, the LERZ eruption had destroyed >700
structures, in addition to roadways and utility
infrastructure.
The 2018 LERZ eruption was supplied by
magma from Kīlauea’s summit reservoir com-
plex and middle ERZ ( 8 ). The summit lava
lake,activeforadecadeintheHalema‘uma‘u
pit crater, drained in early May, and the floor
of Halema‘uma‘u began to collapse in a piece-
meal manner. Beginning in late May and con-
tinuing into early August, broader parts of the
caldera floor also began to collapse in large
episodic events of several vertical meters in a
piston-like manner, with recurrence intervals
of 25 to 50 hours. Each collapse event released
energy equivalent to a magnitude 5.3 earth-
quake ( 8 ). By early August, the caldera floor
had subsided ~550 m (Fig. 1A).Dual cycles of lava effusion
Within days of its onset in late May, the fissure
8 flow developed a stable proximal channel
that persisted for the next 2 months. Low
fountaining (20- to 80-m high) within the
fissure 8 cone supplied lava to the proximal
channel that consisted of a narrow cascading
spillway 30-m wide and 300-m long (Fig. 1C
and movie S1). The spillway emptied into a
perched pāhoehoe channel up to 430-m wide.
The vigor of lava in the fissure 8 spillway
displayed two time scales of cyclic fluctuation
(Fig. 1C): short-term“pulses”had periods of 5
to 10 min and long-term“surges”seemed to
occur soon after summit collapse events.RESEARCH
Patricket al.,Science 366 , eaay9070 (2019) 6 December 2019 1of10
(^1) U.S. Geological Survey, Hawaiian Volcano Observatory, Hilo,
HI 96720, USA.^2 U.S. Geological Survey, Alaska Volcano
Observatory, Anchorage, AK 99508, USA.^3 U.S. Geological
Survey, Cascades Volcano Observatory, Vancouver, WA
98683, USA.^4 U.S. Geological Survey, California Volcano
Observatory, Menlo Park, CA 94025, USA.^5 School of
Integrated Arts and Sciences, Hiroshima University, Higashi
Hiroshima, Hiroshima 739-8521, Japan.^6 Graduate School of
Natural Science and Technology, Kanazawa University,
Kakuma, Kanazawa, 920-1192, Japan.
*Corresponding author. Email: [email protected]
on December 12, 2019^
http://science.sciencemag.org/
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