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GSA TODAY | FEBRUARY 2016 Michael Poland, U.S. Geological Survey Cascades Volcano Kīlauea’s outbreak was noteworthy for its potential
Observatory, Vancouver, Washington 98683, USA; mpoland@usgs (and uncertain) impact and long months of anticipation by
.gov; Tim R. Orr, James P. Kauahikaua, Steven R. Brantley, Janet communities at risk. Had the flow extended far enough along
L. Babb, Matthew R. Patrick, Christina A. Neal, Kyle R. Anderson*, the path it was following, it would have crossed a highway used
Loren Antolik, Matthew Burgess, Tamar Elias, Steven Fuke, by thousands of vehicles each day; isolated a portion of the
Pauline Fukunaga, Ingrid A. Johanson, Marian Kagimoto, Kevan island that is home to nearly 10,000 residents (Callis, 2014); cut
Kamibayashi, Lopaka Lee, Asta Miklius, William Million, Cyril power, water, and other infrastructure on which those residents
Moniz, Paul G. Okubo, A. Jeff Sutton, T. Jane Takahashi, Wes A. depend; and overrun homes in multiple communities.The flow
Thelen**, William Tollett, and Frank A. Trusdell, U.S. Geological stalled repeatedly within several hundred meters of the highway,
Survey Hawaiian Volcano Observatory, Hawai‘i National Park, destroying only one house before breakouts ~15 km upslope
Hawai‘i 96718, USA in March 2015 diverted lava away from the front.The activity
provided new information about the behavior of pāhoehoe lava
ABSTRACT flows, as well as lessons about communicating information to
the public during a prolonged crisis.Although the 2014–2015
Lava flow crises are nothing new on the Island of Hawai‘i, crisis has passed, the lava flow remains active and could threaten
where their destructive force has been demonstrated repeatedly communities in the future.
over the past several hundred years.The 2014–2015 Pāhoa lava
flow crisis, however, was unique in terms of its societal impact SETTING THE STAGE
and volcanological characteristics. Despite low effusion rates, a
long-lived lava flow whose extent reached 20 km (the longest at Kīlauea, one of the most active volcanoes in the world, has
Kīlauea Volcano in the past several hundred years) was poised erupted almost continuously from East Rift Zone (ERZ) vents
for months to impact thousands of people, although direct since 1983 and from a vent at the summit (which hosts an active
impacts were ultimately minor (thus far). Careful observation lava lake) since 2008 (Orr et al., 2015a; Patrick et al., 2015a)
of the flow reaffirmed and expanded knowledge of the (Fig. 1).The current ERZ eruption has extruded more than 4 km3
processes associated with pāhoehoe emplacement, including of lava, covering more than 142 km2 of land (updated from Orr
the direct correlation between summit pressurization and et al., 2015a). Such a large amount of lava has had a significant
flow advance, the influence of existing geologic structures on impact on island residents, destroying 215 primary structures as
flow pathways, and the possible relationship between effusion of 2015, including nearly all of the village of Kalapana in 1990.
rate and flow length. Communicating uncertainty associated Roads and other infrastructure have also been covered, and vog
with lava flow hazards was a challenge throughout the crisis, (volcanic smog) has impacted the health of people, animals, and
but online distribution of information and direct contact with agricultural products across the island.
residents proved to be effective strategies for keeping the public
informed and educated about flow progress and how lava flows Pu‘u ‘Ō‘ō, a cinder cone and lava shield, is the dominant vent
work (including forecasting limitations).Volcanological and for the ongoing ERZ eruption, although other vents within a few
sociological lessons will be important for inevitable future lava kilometers uprift and downrift have also been active. Following
flow crises in Hawai‘i and, potentially, elsewhere in the world. an uprift fissure eruption in March 2011, lava slowly filled the
crater of Pu‘u ‘Ō‘ō until September 2011, when a small fissure
INTRODUCTION eruption on the east flank of the cone fed the informally named
Peace Day lava flow. A lava tube system developed, and within
Basaltic lava flows were very much in the news in 2014. In weeks, lava flowed southeast from the vent more than 10 km
August of that year, Bárðarbunga erupted in Iceland, eventually to the Pacific Ocean (Orr et al., 2015a).While this behavior is
extruding more than a cubic kilometer during six months of common for the current ERZ eruption, the lava discharge rate
activity (Gíslason et al., 2015). Pico do Fogo in the Cape Verde for the Peace Day flow was low (1–2 m3/s), which is about half the
islands began erupting in November, sending out lava flows that average rate measured since 1983 (Poland, 2014).
overran two villages and displaced ~1,000 people (González
et al., 2015).And in June 2014, an outbreak of lava at Kīlauea The eruption remained relatively stable until January 2013,
Volcano sent flows toward communities in the Puna District on when lava overtopped the crater of Pu‘u ‘Ō‘ō and spread to
the east side of the Island of Hawai‘i (Fig. 1). the northeast.The new flows, informally named the Kahauale‘a
flows (Patrick et al., 2015b), gradually became dominant, and the
Peace Day flow ceased activity by November 2013.The northeast
trajectory of the Kahauale‘a flows was significant because of the
GSA Today, v. 26, no. 2, doi: 10.1130/GSATG262A.1.
* Now at U.S. Geological Survey California Volcano Observatory, Menlo Park, California 94025, USA.
** Now at U.S. Geological Survey Cascades Volcano Observatory, Vancouver, Washington 98683, USA.
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