Report on Kilauea (United States) — December 2018
Bulletin of the Global Volcanism Network, vol. 43, no. 12 (December 2018)
Managing Editor: Edward Venzke. Report research and preparation by: Liz Crafford.
Kilauea (United States) Lava fountains on the Lower East Rift Zone build 50-m-high pyroclastic cone and 13-km-long lava flow that engulfs Kapoho Bay during June 2018; 533 homes destroyed since 1 May
Please cite this report as:
Global Volcanism Program, 2018. Report on Kilauea (United States). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 43:12. Smithsonian Institution.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
Kilauea's East Rift Zone (ERZ) has been intermittently active for at least two thousand years. Open lava lakes and flows from the summit caldera and East Rift Zone have been almost continuously active since the current eruption began in 1983. A marked increase in seismicity and ground deformation at Pu'u 'O'o Cone on the upper East Rift Zone on 30 April 2018 and the subsequent collapse of its crater floor marked the beginning of the largest lower East Rift Zone eruptive episode in at least 200 years.
During the month of May 2018 there were 24 fissures that opened along a 6-km-long NE-trending fracture zone on the lower East Rift Zone spawning lava flows in multiple directions, including several that traveled about 5 km SE to the coast; at least 94 structures were destroyed in the Leilani Estates subdivision and adjacent areas (BGVN 43:10). As lava emerged from the fissures, the lava lake at Halema'uma'u drained and explosions produced plumes that spread minor amounts of ash to downwind communities. At the end of May eruptive activity refocused around fissure 8, which began fountaining lava tens of meters into the air and creating a voluminous incandescent flow that headed downslope to the NE. The eruptive events of June 2018 (figure 386), the second month of this episode, are described below with information provided primarily from the US Geological Survey's (USGS) Hawaii Volcano Observatory (HVO) in the form of daily reports, volcanic activity notices, and abundant photo, map, and video data.
Summary of events during June 2018. Lava fountains from fissure 8 were reaching 60 m in height on 29 May 2018 and producing a vigorous stream of lava that traveled rapidly downslope. Several lobes of lava advanced ENE, some at rates of several hundred meters per hour. Fissure 18 was also generating a narrow flow that headed SE for 3 km before stopping. A spatter cone began growing at fissure 8 and reached 30 m in height in just a few days. On the morning of 2 June the fissure 8 flow covered the Four Corners Intersection of Highways 132 and 137, and continued E and then SE around Kapoho Crater; lava flowed into the crater and evaporated the fresh water lake inside. Traveling at a rate of about 75 m per hour, the flow moved towards the shore and reached Kapoho Bay late on 3 June, where it began building a delta. In just a few days the delta was a kilometer in width, and lava was entering the ocean in many streams along the flow front, generating dense plumes of steam and laze.
By 15 June the fissure 8 cone had reached just over 50 m in height. Fissure 8 lava fountains persisted at 40-70 m high for all of June, feeding the 13-km-long channel to Kapoho Bay. Periodic overflows along the channel built up the levees on either side of the fast-moving river of lava; they were short-lived and traveled only a few meters. Flow speeds slowed as the lava spread out over the delta, which reached 150 hectares (380 acres) in size by 20 June. The ocean-entry points migrated north and south along the delta over the course of the month, expanding the width of the ocean entry area to over 3 km. Towards the end of June, lava was crusted over in the delta up to 1 km back from the ocean, and molten material was traveling within the interior of the earlier flows to the ocean. Minor oozing of lava was reported from a few other fissures during the month, but no other significant flow activity was observed.
Within Halema`uma`u crater at the summit a near-daily pattern of collapse explosion events was due to the subsidence caused by the magma withdrawal. As the crater subsided, its rim and walls slumped inward and large blocks dropped down along growing fractures around the caldera with seismic energy releases greater than M 5.0 almost every day. The deepest part of the crater had reached 400 m below the caldera floor by late June.
Activity at the Lower East Rift Zone during 29 May-4 June 2018. By 29 May, activity on Kilauea's lower East Rift Zone was focused on the vigorous eruption of lava from fissure 8 advancing rapidly downslope towards Highway 132. Lava fountains from fissure 8 reached 60 m in height on 29 May, feeding a flow that advanced NE over a flow from a few days earlier. The first lobe of the flow crossed Highway 132 just before 1400 that afternoon and continued NE. Most of the flow remained on the S side of the highway as it moved downslope. Visual observations in the early afternoon also confirmed continued weak activity at fissures 18 and 16. Fissure 18 had produced channelized flows which advanced about 2.6 km toward the coast during the previous day. At the ocean entry on the SE coast, only a few small channels of lava were still entering the ocean. Fissure 8 maintained high fountains throughout the day and into the overnight of 29-30 May with sustained heights exceeding 60 m and multiple secondary fountains that reached 20 m. As the flow moved downslope along the highway, the advance rates accelerated overnight, reaching approximately 550 m/hour. Overnight, sporadic bursts of activity were also observed from fissures 7 and 15.
Fissure 8 maintained fountains that rose 60-75 m high on 30 May. The flow split into three lobes; the two easternmost lobes advanced in a more ENE direction while the westernmost lobe advanced in a NE direction (figure 387). The flow rate had dropped to around 90 m/hour by late afternoon and slowed further to 45 m/hour by late evening. The fissure 18 flow also remained active, moving downslope toward Highway 137 at rates of less than 90 m/hour. By late afternoon, the front of the fissure 18 flow was about 1 km from Highway 137 and was spreading and slowing (figure 388). In the late afternoon, a new flow lobe began branching from the S side of the fissure 18 flow approximately 2 km upslope from the flow front. Throughout the day, sporadic bursts of activity were also observed from fissures 22, 6, and 13.
|Figure 388. Kilauea's Lower East Rift Zone had many active flow fronts as of 1500 HST on 30 May 2018. Active fissures and flows are shown in dark red. Shaded purple areas indicate lava flows erupted in 1840, 1955, and 1960. Courtesy of HVO.|
Four lobes of the fissure 8 flow advanced on 31 May (figure 389), fed by persistent fountaining that reached heights up to 80 m. A spatter cone was forming on the downwind side of the fountain and was approximately 30 m high. The fountains were feeding the flow to the NE, and minor overflows from the growing fissure 8 channel were occurring along its length, covering several of the remaining roads in Leilani Estates. The front of the flow advanced at about 90 m/hour through agricultural lands and was within 1.7 km of the Four Corners area (the intersection of Highways 132 and 137) by the evening. The fissure 18 flow that had advanced to within 1 km of Highway 137 had stalled. The new flow that branched from the fissure 18 channel 2 km upslope appeared to have captured most of the lava output from fissure 18. It descended downslope just to the S of the previous flow. Lava was pooling around the vent of fissure 22 throughout the day.
The advance rates of the distal part of the fissure 8 flow were low overnight on 31 May-1 June as lava ponded in a flat area, but flow continued throughout the day to within 0.5 km of the Four Corners intersection of Highways 132 and 137 by evening; fissures 18 and 22 were inactive. By 0645 on 2 June it was about 100 m from the intersection (figure 390). Around 0930 on 2 June a broad front over 275 m in width extending both north and south of Highway 132 (figures 391) crossed the intersection and continued advancing into Kapoho Crater (sometimes called Green Lake Crater) and Kapoho Beach Lots. It entered Green Lake within the crater, creating a large steam plume that was visible until 1330. The Hawaii County Fire Department reported around 1500, after an overflight, that lava had filled the lake and apparently boiled away all the water.
The flow continued to advance overnight on 2-3 June along an 800-m-wide front towards the ocean at Kapoho Bay between Kapoho Beach Road and Kapoho Kai Drive. As of 0700 on 3 June, the lava flow was around 450 m from the ocean (figures 392 and 393) traveling at a rate of about 75 m/hour. By 1745 it had advanced to within 225 m of the ocean at its closest approach point. The other branches of the fissure 8 lava flow were inactive, and all other fissures were inactive, although observers on the late afternoon overflight noted abundant gas emission from fissures 9 and 10 and incandescence without fountaining at fissures 16 and 18.
|Figure 392. At 0700 HST on 3 June 2018 Kilauea's LERZ fissure 8 flow front was about 450 m from the ocean, advancing at about 75 m/hour. View is to the W looking up the flow front. Nearly all of the front was active and advancing. Courtesy of HVO.|
Fountaining lava 45-75 m high at fissure 8 continued overnight on 3-4 June, feeding the growing lava channel flowing NE along Highway 132 to the Kapoho area. Throughout 30 May-3 June tephra landing downwind from the fountaining produced a growing pyroclastic cone at fissure 8 (figure 394). Local videographers reported that lava entered the ocean at Kapoho Bay at about 2230 HST on 3 June and began constructing a delta (figure 395); by late afternoon the next day the delta extended about 640 m into the bay. A laze plume (a corrosive seawater steam plume laden with hydrochloric acid and fine volcanic particles) was blowing inland from the ocean entry but dissipating quickly. The lava flow front was about 800 m wide. A lava breakout was also occurring upslope (N) of the Kapoho cone cinder pit. A lava breakout from the S margin of the flow near the intersection of Highway 132 and Railroad Avenue had completely encircled Kapoho Cone by the end of the day.
Activity at the Lower East Rift Zone during 5-12 June 2018. The intensity of the fountaining at fissure 8 declined overnight on 4-5 June to between 40-50 m in height, not far above the top of the cone formed during the previous several days (figure 396). By the early morning of 5 June the fissure 8 flow had completely filled Kapoho Bay, extending 1.1 km from the former coastline (figure 397). On the south side of the ocean entry, lava was entering the water at the Vacationland tidepools, having inundated most of that subdivision. To the north, lava had covered all but the northern part of Kapoho Beach Lots. The northernmost lobe of the fissure 8 flow, in the Noni Farms Road area, advanced downslope about 180 m overnight (figure 398) and continued to slowly advance during the day on 5 June.
By the morning of 6 June 2018, the lava fountaining at fissure 8 continued to reach heights of 45-55 m and feed a stable channel to the NE and E (figure 399) to the ocean entry in the Kapoho Bay area. The lava delta that formed at the bay had also extended slightly outward overnight; during the day on 6 June a lateral lobe of the flow pushed slowly N through what remained of the Kapaho Beach Lots subdivision. Overnight on 6-7 June and throughout the following day the fountain heights from fissure 8 fluctuated between 58 and 70 m feeding the channel with vigorous flow (figure 400). The delta was about 1.9 km wide in the Vacationland/Waopae area and the flow was expanding northward (figure 401). By the late afternoon overflight on 8 June, two vigorous steam plumes were rising from the ocean flow front and being blown inland. Strong thermal upwelling was noted in the ocean extending up to 900 m out to sea from the visible lava front. Heavy gas and steam emissions were noted at fissures 9 and 10, but lava emission was occurring only at fissure 8.
Overnight on 8-9 July the fountains at fissure 8 were slightly lower, reaching heights of 40-55 m. Fissure 22 was incandescent and there was minor lava activity at fissures 16/18 while the fuming from fissures 24, 9, and 10 had decreased from the previous day. The fissure 8 flow had created a lava delta approximately 80 hectares (200 acres) in size by the morning of 9 June, filling Kapoho Bay and covering shallow reefs along the nearby coastline (figure 402); observers that night also noted vigorous convection taking place up to 1.5 km offshore from the entry points. Minor levee overflows along the upper part of the channel occurred on 10 June from the strong channelized flow (figure 403). Near the Four Corners region the channel was incandescent and flowing vigorously.
By the evening on 10 June, three closely spaced lava fountains at fissure 8 were erupting with maximum heights reaching 35-40 m (figure 404), feeding the fast moving channelized and braided flow that now traveled 13 km to the ocean at Kapoho Bay (figure 405). A strong steam plume was observed on the S end of the ocean entry with frequent steam explosions at the flow front. Weak lava activity continued during 10-12 June at fissures 16/18 as it had for the previous several days (figure 406). Incandescence was noted at fissures 15 and 22 on 12 June. Lava was entering the ocean over a broader area than before with several minor incandescent points and small plumes, and two larger entries and corresponding plumes. The fissure 8 cinder cone had reached about 43 m in height by the evening of 12 June.
Activity on the Lower East Rift Zone during 13-19 June 2018. Lava fountaining at fissure 8 during 13-19 June generally rose 30-50 m with intermittent bursts as high as 60 m. The growing cone was 52 m at its highest point on 15 June (figure 407). From fissure 8, lava flowed freely over small cascades (rapids) into a well-established channel (figure 408). Near the vent, channel lava was traveling about 24 km/hour; it slowed as it traveled the 13 km-long-channel (figure 409) to about 2 km/hour near the ocean entry at Kapoho Bay. Minor amounts of lava periodically spilled over the channel levees.
|Figure 407. Lava fountains were still rising higher than the 52-m-high cone at Kilauea's LERZ fissure 8 on 15 June 2018. Courtesy of HVO.|
Several laze plumes rose along the ocean entry margin as break outs fed many small and large flows during mid-June. The largest pahoehoe breakout area was on the northern margin of the flow (figure 410). A small amount of expansion continued at the southern boundary of the flow near the coast and south of Vacationland. By 17 June, lava flowing into the ocean had built a delta of flows, rock rubble, and black sand, which was over 121 hectares (320 acres) in size. The flow front at the coast was about 2.4 km wide by 18 June. Limited spattering and small flows were also observed at fissures 16 and 18 during 13-19 June; mild spattering from fissure 15 was observed late in the day on 16 June, and incandescence and mild spattering were observed from fissure 6 on 17 June.
|Figure 410. A large breakout of lava created several laze plumes as it entered the ocean along the northern ocean entry margin of Kilauea's LERZ fissure 8 flow delta on 14 June 2018. Courtesy of HVO.|
Fissure 8 lava fountains 52-70 m tall showered spatter onto the cone overnight into 19 June (figure 411). Small overflows were observed on the N side of the channel near Pohoiki Road overnight and in the morning, with one breakout spreading slowly beyond the flow boundary. Field crews on the ground near fissure 8 midday on 19 June observed a still-vigorous channelized lava flow being fed by fountains at the vent. Standing waves were visible within the channel and cascades/rapids were visible near the base of the 50-m-high cone. The maximum flow velocity in the channel was measured at 28 km/hour. During the morning overflight, several small overflows could be seen along the channel margins. The flow of lava was faster in the center of the channel and decreased in speed toward the margins where friction with the channel walls increased. A small, sluggish overflow along a section of Luana Street was advancing NW. Fissures 6, 15, 16 were still oozing lava and fuming.
|Figure 411. Kilauea's LERZ fissure 8 vigor increased overnight on 18-19 June 2019 with lava fountains reaching up to 60 m. Spatter continued to build up on the E flank of cone and lava flowed into the channel. Courtesy of HVO.|
Activity at Halema'uma'u crater during June 2018. Throughout June intermittent explosions and earthquakes continued at Halema'uma'u crater as the summit area subsided and adjusted to the withdrawal of magma from below. Inward slumping of the rim and walls of Halema`uma`u continued in response to the persistent subsidence. A near-daily pattern of explosive events was characterized by seismicity at the summit that would gradually increase to tens of events per hour, culminating with a larger explosion, often with an energy release equivalent magnitude greater than M 5.0. Seismicity would usually then drop significantly before gradually rising until the next explosion. Ash plumes from the explosions often rose to altitudes of 2.4-4.6 km. With each explosion, Halema'uma'u crater subsided, generating fractures and down-dropped blocks within and around the crater floor, dramatically reshaping the morphology of the summit caldera in just a few weeks (figures 412 and 413).
Overnight on 10-11 June there were two explosions at the summit separated by about four hours, followed by a decrease in seismicity. Video recorded during a UAS (Unmanned Aircraft Systems) flight HVO on 24 June 2018 revealed details of the extensive changes occurring within Halema'uma'u crater since explosive eruptions of ash and gas and ongoing wall collapse had begun in mid-May. Clearly visible were the steep crater walls that continued to slump inward and downward with ongoing subsidence. The deepest part of Halema'uma'u had dropped over 400 m below the caldera floor. There were two obvious flat surfaces within the crater that had slumped downward as nearly intact blocks; the shallower one was the former caldera floor and the deeper one was the former Halema'uma'u crater floor. HVO reduced the Aviation Color code from Red to Orange on 24 June, citing the fact that the episodic plumes from the summit rarely exceeded 3 km altitude where the might pose a risk to aviation.
Activity on the Lower East Rift Zone during 20-30 June 2018. For the remainder of June, vigorous fountaining nearly 60 m high from fissure 8 fed the established channel that transported incandescent lava to the ocean at the Kapoho coastline where several entries were active (figure 414). The largest entry area was at the S end of the flow front, but the locations of the ocean entry points migrated back and forth along the delta over time. Periodic overflows from the channel were short-lived and produced sluggish pahoehoe flows that only traveled a few meters (figure 415). Minor effusion of lava was observed from fissures 6, 15, and 16. Activity ceased at fissure 6 by 22 June. During an overflight in the early morning of 23 June, only incandescence was noted at fissure 22.
The spatter cone grew to 55 m tall by 24 June, after which the lava fountains only occasionally rose above its highest point. Geologists measured lava entering the channel traveling as fast as 30 km/hour. By 25 June, most of the lava was entering the sea on the southern side of the flow front along a 1-km wide area marked by billowing laze plumes, although the lava front extended for more than 3 km along the coast (figure 416). Beginning on 27 June geologists observed fresh lava oozing at several points along the northern margin of the flow field in the area of the Kapoho Beach Lots. By then, the lava channel had crusted over about 0.8 km inland of the ocean entry; lava was moving beneath the crust and into the still-molten interior of earlier flows before it entered the sea (figure 417). The same day, small overflows on both sides of the channel occurred in the uppermost part of channel, but none of these overflows extended past the existing flow field (figure 418).
The northern margin of the ocean entry flow field was the most active during the last few days of the month with lava entering the sea over a broad area (figure 419). A few burning areas were also observed on the S side of the flow and W of Highway 137. Field crews were able to make rough estimates of the velocity of the flow in the channel by timing the large blocks in the flow as they passed by islands within the channel and known points along the edges (figure 420). Volcanic gas emissions were very high from fissure 8 eruptions throughout June 2018 causing trade winds to bring Vog (volcanic air pollution, a hazy mixture of SO2 gas and aerosols) to the central, south, and western parts of the Island of Hawaii on many occasions. Substantial SO2 plumes were recorded daily (figure 421).
|Figure 419. At the Kapoho coast, lava from Kilauea's LERZ fissure 8 entered the ocean over a broad area along the northern margin of the flow field on 30 June 2018. Courtesy of HVO.|
Thermal observations during May-June 2018. The MODVOLC thermal alert system captures infrared data from satellite instruments (MODIS) that indicate the location of hot-spots around the planet. The data collected for Kilauea for May and June 2018 clearly indicated the size and scope of the eruptive episode (figures 422 and 423). At the end of April, infrared data indicated strong activity at Halema'uma'u and weak activity from the episode 61g flow that originated on the flank of Pu'u 'O'o (figure 422). The first MODVOLC thermal alert of activity on the LERZ appeared 6 May; even though the lava lake had begun to drop, there was still a strong thermal signal at Halema'uma'u that day as well. As the eruption progressed during May, the increasing size of the effusive activity that included lava flows reaching the SE coast was apparent.
By early June, just a few days after the flow-volume increase on the LERZ from the channel emerging from fissure 8, the new pattern of heat flow to the N and NE around Kapoho Cone was recorded in the satellite data. The growing delta filling Kapoho Bay generated a strong infrared signal throughout the month. Although the fissure 8 flow was essentially unchanged in its thermal output on 22 and 23 June based on ground observations, the infrared data for those two days was significantly different, likely reflecting atmospheric conditions that blocked satellite views. In spite of this, the general nature of the flow activity is still clear in the data. By the end of June, the extent of the MODVOLC thermal alert pixels clearly indicated the robust nature of the continuing eruption.
Geologic Background. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 km2, destroying nearly 200 houses and adding new coastline to the island.
Information Contacts: Hawaiian Volcano Observatory (HVO), U.S. Geological Survey, PO Box 51, Hawai'i National Park, HI 96718, USA (URL: http://hvo.wr.usgs.gov/); NASA Goddard Space Flight Center (NASA/GSFC), Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).