Science - 06.12.2019

Pulses: short-term fluctuations
Numerous field crews reported substantial
fluctuations in the level, speed, and agitation
of lava in the spillway, occurring over time
scales of minutes. Time-lapse imagery of the
lava level and the seismic tremor amplitude
[as shown by its proxy, real-time seismic am-
plitude measurement (RSAM) ( 29 )] at nearby
seismic station KLUD (Fig. 1B) provide de-
tails on this pulsing behavior and highlight
the pulsing and nonpulsing regimes of vent
activity (Figs. 2, A to C, and 3, A to C, and
movieS2).Duringnonpulsingregimes,the
lava level had a relatively steady height (Figs.
2A and 3B), with minor fluctuations (ampli-
tudes of <2 m). RSAM was relatively steady
(Fig. 3, A and B). During pulsing regimes,
rapidly oscillating lava levels in the spillway

were anticorrelated with seismic tremor

(RSAM) and infrasound energy (Fig. 3C).

Sporadic pulsing regimes comprised 35% of

a 10-day period of observation in July (Fig.

3A), with durations of 1 to 18 hours (mean

6.4 hours).

During pulsing regimes, activity alternated

between the lava channel and the fissure 8

crater. When the lava level in the channel

peaked during pulsing, an unmanned aircraft

system (UAS) and ground-based video showed

a more rapid flow and a more agitated surface

(less crust) (Figs. 2D and 4A and movie S3).

Ground-based thermal images showed higher

temperatures in the plume above the spillway

(Fig. 3D), consistent with the visibly robust

plume there and suggesting higher outgassing

from the channel, whereas the gas plume at

the vent was weaker and cooler, suggesting

lower gas emission (Fig. 3D) and consistent

with more subdued fountaining and weaker

bubble bursts at the vent (Fig. 4A). At these

times, RSAM and infrasound were relatively

low (Fig. 3C).

Conditions were reversed during troughs in

the pulsing. During these times, the lava in

the channel was low and sluggish and the

channel surface was more crusted and placid

(Figs. 2D and 4B). Fountaining in the vent

crater was more active, with extensive bubble

bursting and a more robust gas plume (Fig. 4B),

and thermal images indicated higher temper-

atures in the plume above the vent, suggest-

ing higher outgassing there (Fig. 3D). RSAM

and infrasound were high during these pe-

riods (Fig. 3C).

Patricket al.,Science 366 , eaay9070 (2019) 6 December 2019 2of10

Island of Hawai‘i

Area of

10 km map

Kīlauea

caldera

(summit)

Pu‘u ‘Ō‘ō

flow field

(1983-2018)

Lower East Rift

Zone flow field

(May-Sep 2018)

Pāhoa

Kalapana

East Rift Zone

Mauna Loa

Leilani

Estates

Nanawale

Estates

Kapoho

Hwy 130 Crater

2 km

Lava flows from

fissures 1-7,

9-24

Lava flow from

fissure 8

(dashed line is

channel)

KLUD Fissure 8

Quarry

time-lapse

camera

Ea

st (^) Rift Zone
A
B
0100m
Spillway
time-lapse
camera
Video+thermal
camera Fissure 8
crater (vent)
Spillway
Channel
margin
1
2
Leilani Ave.
Nohea St.
1
2
Spillway
Perched channel
Low fountaining at vent
(fissure 8 crater)
D
C
Papaya
Farms Rd.
Noni Farms
Rd.
Image ©2018 Planet Labs Inc., cc-by-sa 4.0
Infrasound
array
UWD
POO
JKA
Ocean entries
Ocean entries
Fig. 1. Setting of the 2018 eruption.(A) Map of Kīlauea Volcano and the ERZ.
Kīlauea forms the southeast portion of the Island of Hawai‘i. The Pu‘u‘Ō‘ō
eruption (1983 to 2018) ended at the onset of the LERZ eruption (May to
September, 2018). Both eruptions were fed by magma supplied from the
summit magma reservoir complex along a conduit that follows the ERZ. A
large portion of the summit caldera floor collapsed and subsided in response
to the LERZ eruption. White dottedline indicates the boundary between
Kīlauea and Mauna Loa. (B) Close-up of the LERZ. Fissure 8 was active for
~2 months and formed the majority of the lava flow field. KLUD is a seismic
station. (C) Aerial image looking east, showing the proximal sections of
the fissure 8 flow. Lava flowed through a narrow spillway that then emptied
into a broader perched channel. Numbers 1 (island) and 2 (high rim) mark
spots shown in (D). Photo was taken July 29, 2018. (D) Post-eruption satellite
image of the fissure 8 vent region and proximal lava channel. Measurements
of lava level in the channel and flow velocities were targeted at the section
of channel between points 1 and 2.Image courtesy of Planet Labs.
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