PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
December 2018
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By Michael Zoeller, Matthew Patrick, and Christina Neal
Crisis Remote Sensing during the 2018 Lower East Rift Zone Eruption of K lauea Volcano
Kīlauea Volcano, Hawai‘i, is renowned as one of the most ac-
tive and closely monitored volcanoes on Earth. Scores of seis-
mometers and deformation sensors form an array across the
volcano to detect subsurface magmatic activity, and ground
observers track eruptions on the surface. In addition to this
dense ground-based monitoring, remote sensing – both air-
borne and spaceborne – has become a backbone tool at the
U.S. Geological Survey’s (USGS) Hawaiian Volcano Observa-
tory (HVO) for mapping activity and forecasting volcanic haz-
ards. Remote observations were critical components of HVO’s
response to the historically unprecedented 2018 eruption
from Kīlauea’s lower East Rift Zone (ERZ); here we describe
some of the many types of remote sensing tools that were uti-
lized, and the specific monitoring roles they filled.
For decades, remote sensors have watched for signs of activ-
ity, responded to eruption crises, and mapped both old and
active lava flows from Kīlauea. In the 1980s and 1990s, lava
flow mapping was accomplished with aerial photography
supplemented by extensive field checking. Later, GIS and
handheld GPS units improved the accuracy and turnaround
time of lava flow maps.
1
Over the past year, HVO and USGS
colleagues have utilized innovative new remote sensing tools
– described herein – for both detailed and synoptic views of
rapid changes that unfolded during the 2018 effusive erup-
tion. Satellite tasking and data were provided by activation of
the International Charter for Space and Major Disasters (the
“Disaster Charter”), a global partnership of space agencies
that provides satellite data for the benefit of disaster man-
agement during emergencies. Other remote-sensing data
were collected from a range of aircraft-mounted and hand-
held tools, which acquired a diversity of thermal, visual, gas,
and geophysical data.
The 2018 eruption was preceded by 35 years of nearly contin-
uous lava effusion at and near Pu‘u ‘Ō‘ō, on Kīlauea’s middle
ERZ. During these years, lava flows from Pu‘u ‘Ō‘ō covered
144 square kilometers and destroyed 215 structures, includ-
ing several residential subdivisions. Pu‘u ‘Ō‘ō activity contin-
ued through March and April 2018, when ground inflation in
this area suggested increasing pressure, culminating in a col-
lapse of the Pu‘u ‘Ō‘ō crater floor on 30 April. Over the follow-
ing days, ground- and space-based instruments tracked the
advance of a magmatic intrusion eastward along the lower
ERZ of Kīlauea. Slight inflation of the ground surface – on the
order of centimeters – was detectable by synthetic-aperture
radar (SAR) images. HVO and USGS geophysicists produced
interferograms from SAR images collected before and during
the intrusion (Figure 1), which pinpointed its leading edge
under the Leilani Estates subdivision. The eruption began
within this residential area on 3 May.
Eruption vigor increased dramatically in mid-to-late May
and lava quickly reached the ocean. This transition coincid-
ed with enhanced collapse of the caldera floor at the summit
of Kīlauea, where SAR interferograms proved to be a great
predictor of the next areas to begin subsiding. As lava began
devastating larger swaths of east Hawai‘i, the need for quick
and accurate flow mapping became critical. USGS analysts
with the National Civil Applications Center derived geospa-
tial vector data from an array of satellite imagery – includ-
ing some from the Department of Defense’s National Imag-
ery System – and other remote sensing products, many of
which had been acquired and made available by the Disaster
Charter. These satellite-derived vector data were reviewed
to ensure alignment with field observations by USGS ground
crews and helicopter overflights, and then used as the prima-
ry source for HVO’s eruption geodatabase and lava flow maps
released daily to the public.
Thermal imagery added another layer to HVO’s under-
standing of lava flow dynamics during the eruption, as
oblique overlapping images were collected with a handheld
thermal camera during daily helicopter overflights. Struc-
ture-from-motion software was used to stitch the images into
an orthomosaic that provided a synoptic thermal map of the
flow field.
2
These routine thermal maps, published online on
the same day as the overflight, were invaluable for assessing
Photogrammetric Engineering & Remote Sensing
Vol. 84, No. 12, December 2018, pp. 749–751.
0099-1112/18/749–751
© 2018 American Society for Photogrammetry
and Remote Sensing
doi: 10.14358/PERS.84.12.749
