Bogoslof 2016/12
Start: December 12, 2016 [1]
Stop: August 30, 2017 [2]
Event Type: Explosive
Max VEI: 3 [3]
- Tephra plume [1]
- Island-forming [1]
- Submarine [1]
- Geomorphologic change [1]
- Phreato-magmatic [1]
- Lava dome [1]
Description: From Coombs and others (2019): "Without a local seismic network, precursory seismicity was only recognized retrospectively. Wech et al. (2018) show that seismicity first occurred in September in the form of volcano-tectonic earthquakes, mostly on September 28-29 (swarm S1of Tepp et al. 2019). Wech et al. (2018) interpret these events as likely caused by magmatic intrusion into the middle to upper crust. A smaller earthquake swarm occurred in early October, with sporadic earthquakes continuing until the eruption in December (Tepp et al. 2019).
"From December 12 through March 13, explosions occurred at a mean rate of once every 58 h (2.4 days). Many of the explosions during this period were preceded by repeating earthquakes that accelerated into an explosion, characterized by increasing magnitude and becoming closer together in time, described by Wech et al. (2018) as 'slow-clap' seismicity and also described in Tepp et al. (2019) and Tepp and Haney (2019). On the basis of T-phase character, Wech et al. (2018) interpret these as occurring in the shallow crust.
"Seismicity remained at fairly low levels in October and November. In early December, days before the first detected infrasound, earthquakes with weak T-phases again suggested mid- to shallow-crustal magma movement (Wech et al. 2018). On December 12, the first infrasound signal from Bogoslof marked the beginning of the eruption. The signal, later recognized as event 1, was accompanied by a weak seismic signal, but no cloud was observed in satellite images. Infrasound for event 2, later the same day, has a relatively high frequency index (FI; ratio of high-frequency to low-frequency infrasound), suggesting a subaerial vent (Fee et al. 2019). On December 14, AVO received an email report from St. George, 308 km north-northwest of Bogoslof, about intermittent sulfur smell, likely corresponding to activity at Bogoslof. A Sentinel-2 satellite image taken minutes after event 3 on December 14 captured intense steaming from a subaerial vent and new pyroclastic deposits on the island and suspended in the surrounding ocean (Fig. 4a). Events 4 and 5 occurred on December 16 and 19. These first five explosions were not detected in real time, only after retrospective analysis of data streams. Thus, we have no direct observations of the character of these explosions.
"Satellite imagery beginning December 14 shows that uplift of Bogoslof Island occurred and may have been associated with cryptodome emplacement. A Sentinel-2 satellite image from December 21 (Waythomas et al. 2019a) shows an approximately 300-m long oval-shaped raised mass just north of Castle Rock (a remnant lava dome from the 1796-1804 eruptive period; see Fig. 3). This feature was not present in a Sentinel-2 image from December 14 (Waythomas et al. 2019a; their Fig. 5a). Preliminary analysis of DEMs generated by stereo satellite pairs shows that this feature continued to grow throughout the eruption (A. Diefenbach, written comm. 2019).
"No elevated surface temperatures were seen in satellite monitoring checks at Bogoslof until January 19, and neither the uplifted block nor surrounding areas were visibly steaming in December or January in a way that would be consistent with lava effusion (Figs. 3 and 6). Samples of the material exposed along the steep, eastward face of the uplift (see Waythomas et al. 2019b) are trachyandesite lava with 58-60 wt% SiO2 and are a different composition than the dominant juvenile basalt magma erupted in 2016-2017 (Loewen et al. 2019). Given the lack of thermal signature, as well as the composition of this feature, we suggest that this uplifted feature is likely the roof above a shallow cryptodome.
"Several pilots observed a volcanic cloud in the vicinity of Bogoslof on December 21 (Fig. 4b), and were the first alert to AVO that Bogoslof had become active. A pilot later the same day reported seeing 'a new land mass' in the island cluster. This event, event 6, began a period of activity that lasted a little less than a month, with explosive events 6-22 occurring at a rate of about one every 40 h. They produced volcanic clouds of heights up to 11 km, with variable durations (2 to 102 min), and about half produced detected lightning (Table 1). Most (80 %) consisted of single seismic pulses.
"Some of the only direct observations of activity occurred during event 9 on December 23, when observers aboard a Coast Guard vessel in the area reported ash emissions, lightning, and the ejection of incandescent lava and fragmental material that lasted about an hour. The cloud from event 16 on January 5 rose to 11.8 km asl and was observed by numerous pilots and mariners (Fig. 4c).
"A Worldview-3 image from December 25 (Fig. 6b) shows a bilobate submarine vent area and new pyroclastic deposits enlarging the island and beginning to enclose a vent lagoon. On December 29, data derived from US National Imagery Systems indicated a nearly complete ring of pyroclastic deposits around a more circular, submerged, ~ 450-m-across vent area. On January 10, passengers on a helicopter that flew from Dutch Harbor to Bogoslof took photographs and video of the island that showed discolored and roiling water in the crescent-shaped vent area, and the area of uplift from December (Fig. 3b). A Worldview-3 image from January 11 (Fig. 6c) shows continued growth of the island, and abundant meter-scale ballistics on the north and south ends of the island (Waythomas et al. 2019a, their Fig. 7).
"Satellite images, pilot reports, and ground-based photos show that event 23 on January 18 was the first demonstrably ash-rich cloud of the eruption sequence. Previous explosions produced clouds that were white in color with almost no ash signal in satellite data (Schneider et al. 2019).
"Prior to event 23, as with many other explosions on the first half of the eruption, seismic stations on neighboring islands picked up precursory seismicity in the form of repeating earthquakes that became more closely spaced in time during the runup to the explosion (Tepp et al. 2019). These lasted for about 11 h. Infrasound data show that the explosion itself lasted about 80 min and was pulsatory (Lyons et al. 2019b), with seven discrete bursts of strong seismicity (Searcy and Power 2019). Despite the event’s duration, only modest lightning was produced (14 strokes; Van Eaton et al. 2019).
"Pilots reports, visual satellite images, and thewest-facing FAA web camera in Dutch Harbor (Fig. 4d) indicated that the explosion produced a dark-gray ash cloud. MODIS satellite images show the cloud rose as high as 8.5 kmasl before drifting northeast over the Alaska Peninsula. An ash signal in the brightness-temperature-difference (BTD) satellite retrieval was seen along the leading cloud edge, suggesting that the cloud interior may have been opaque (Schneider et al. 2019). This event produced 1.9 kt of SO2 and was the first since event 13 on December 31 to produce more than 0.2 kt SO2 (Lopez et al. 2019).
"A mid-infrared MODIS satellite image collected minutes after the explosion showed a possible "recovery pixel". These occur when the sensor encounters a very hot object and saturates, suggesting lava or hot tephra must have been present above the water surface (D. Schneider, written comm. 2017). These were the first elevated surface temperatures detected by satellite imagery of the eruption. Clouds moved in to obscure the volcano soon after, with no additional views prior to January 20. Because event 23 was not detected on the Okmok infrasound array, we do not have infrasound FI analysis for this event, which for other events provides information on subaerial versus submarine venting (Fee et al. 2019).
"In the week following event 23, five explosions (events 24-28) occurred with an average repose time of 42 h between them (Table 1, Fig. 8). These events had total infrasound durations of 3-15 min, produced modest lightning, observable volcanic clouds, and each up to 0.6 kt of SO2 (Table 1). None showed a clear ash signature in satellite data.
"A Worldview-2 image acquired about 10 h after event 26 shows the island with a lagoon, open to the east, with two circular craters. The one to the northwest had upwelling within it, suggesting it was above the vent for the event 26 explosion (Waythomas et al. 2019a, their Fig. 8).
"About 84 h after event 28, the longest sustained explosion of the eruptive sequence produced significant ash and resulted dramatic changes to Bogoslof Island. Event 29 comprised more than 10 short-duration explosions that were detected in seismic, infrasound, and lightning data, took place over several hours on January 31, and produced several discrete volcanic clouds.
"The event started with no detected precursors, and activity escalated from 08:40 to 09:30, as indicated by increased seismic tremor and high amplitude infrasound signals. At 09:00, a continuous volcanic plume extended for a distance of more than 200 km towards the east-southeast over Unalaska Island at an altitude of 5.9 km asl. Event 29 produced 190 lightning strokes (Table 1; Van Eaton et al. 2019) and the most significant SO2 emission since December 22, 2016 (3.6 kt; Lopez et al. 2019).
"Tephra accumulation at the vent produced a demonstrably dry volcanic edifice for the first time during event 29. Data derived from US National Imagery Systems shortly after the event showed light steaming from an apparently dry eruption crater about 400 m in diameter and as much as 100 m deep below the west crater rim. Whereas most previous explosive events in the sequence, with the possible exception of event 23 on January 18, issued from a vent in shallow seawater, freshly erupted tephra formed an almost 200-m-wide barrier separating the vent from the sea. A Worldview-3 image from about 15 h later the same day (Fig. 6d) shows that the crater had already begun to fill with seawater. As with several of the events, large ballistic blocks were visible along the island’s north southwest shoreline (Waythomas et al. 2019a, their Fig. 9).
"Event 29 resulted in ashfall on Unalaska Island including trace (< 0.8 mm) amounts in the community of Dutch Harbor/ Unalaska. A sample of ash collected in Dutch Harbor comprises free crystals of plagioclase, clinopyroxene, amphibole, and rare biotite, as well as particles that display a range of groundmass textures from microlitic to glassy, and that vary from dense to vesicular (Loewen et al. 2019). The material is consistent with being a mixture of juvenile basalt scoria and non-juvenile lithics.
"Following event 29, a series of smaller explosive events occurred from February 3 to 20 (events 30-36; Table 1). During this period, the inter-event times became more variable, with some pauses of up to 9 days between events. Explosions during this time lasted minutes to a few tens of minutes, produced clouds that rose from 4.6 to 8.6 km asl (Schneider et al. 2019), 0-92 strokes of lightning (Van Eaton et al. 2019), and modest SO2 (0-1.4 kt; Lopez et al. 2019).
"A series of satellite images from January 31 through February 12 shows little change in the island’s morphology after event 29 (Fig. 6d-e; Waythomas et al. 2019a). Elevated surface temperatures detected in two MODIS images from February 6 likely reflected hot new deposits from event 31 on February 4. A high-resolution Worldview-2 satellite image from February 23 also shows little change except for the presence of ballistics particles ejected during events 32-36 (February 13-20) and distributed across the island (Waythomas et al. 2019a). A clear view from March 3 similarly shows only minor changes (Fig. 6f).
"The final event in this time interval, event 36 on February 20, was an excellent example of a Bogoslof explosion with a precursory seismic sequence (see Fig. 4 of Coombs et al. 2018). A classic sequence of coalescing earthquakes served as a prelude to the series of energetic eruptive signals that made up the event. Earthquakes were first detected at 20:42 on February 19. The sequence then maintained a relatively low rate until about 00:55 (February 20) when the rate suddenly increased to about 30 earthquakes per hour. The rate then progressively increased over the next hour almost merging to tremor by 2:00. Earthquakes ceased at 2:07 and after a1-min break transitioned to tremor. The eruptive signals consisted of about 9 blasts that were captured on multiple infrasound arrays resulting in a 40-min long explosion. The resulting plume reached 6.1 km asl and was elongated, stretching to the east-southeast over Unalaska Island. Pilots and observers on Unalaska Island at the time clearly observed the white, ice-rich cloud (Fig. 4e).
"After a 16-day pause, event 37 on March 8 lasted 200 min. It had the largest infrasound energy (Lyons et al. 2019a), seismic tremor magnitude (Tepp et al. 2019), most lightning (1437 strokes; Van Eaton et al. 2019), largest SO2 emission (21.5 kt; Lopez et al. 2019), and most significant ash cloud (Schneider et al. 2019) of any event in the eruptive sequence (though not the highest reduced displacement; Haney et al. 2019a). VIIRS satellite images showed the resulting cloud reached between 10.6 and 13.4 km asl and drifted east over Unalaska Island. Minor ashfall of a few millimeters was reported by a mariner near Cape Kovrizkha (northwest Unalaska Island; Fig. 1) who collected ash from his vessel. Like the ash sample from January 31, this ash contains particles of juvenile basaltic scoria and free crystals with minor amounts of what appear to be volcanic lithics (Loewen et al. 2019). A barely perceptible ashfall deposit was reported at Unalaska/Dutch Harbor.
"Event 37 also changed the shape of the island and temporarily dried out the vent area, as seen in a Landsat-8 image from March 8 (not shown). In infrasound data, event 37 shows a mix of low and high FI, consistent with an eruption from both submarine and subaerial vent(s) during this event (Fee et al. 2019).
"A March 11 WorldView-3 image (Fig. 6g) shows the west coast of the island grew significantly since March 3 (Fig 6f), with about 250m of new land west of the 1926-1927 dome. A new ~ 150-m wide vent was also observed on the north coast of the island, and ballistics ejecta clustered on the eastern side of the island (Waythomas et al. 2019a, their Fig. 11).
"On March 10 and 11, two multi-hour seismic swarms each produced hundreds of earthquakes as detected on station MAPS (Tepp et al. 2019), but neither led directly to an explosion. A few hours later, a precursory swarm (Tepp et al. 2019) began on March 11 and culminated on March 13 in event 38. This event produced a small cloud that reached as high as 4.1 km asl and drifted south-southwest.
"Following event 38 on March 13, there was a 9-week pause in explosive activity at Bogoslof. The only detected unrest observed during the hiatus was a swarm of volcano-tectonic earthquakes on April 15. The swarm lasted for several hours, comprised 118 detected earthquakes (catalog of Wech et al. 2018) with magnitudes between ~ 0.8 and 2.2, and is interpreted to reflect magmatic intrusion in the mid to upper crust because of the earthquakes’ weak T-phases (Wech et al. 2018).
"Satellite images from this period show the rapid surface reworking and erosion of new volcanic deposits on Bogoslof Island and coastline erosion by wave action (Waythomas et al. 2019a). Photos (Fig. 5a) and a Worldview-3 image from May 11 (Fig. 6h) show that the vent lagoon remained hot throughout the hiatus, evidenced by steam rising from the crater lagoon.
"From May 16 through August 30, AVO detected 32 explosive events at the volcano. In contrast to the events of December 2016-March 2017, few of the explosions in the later phase were preceded by detectable seismic precursors, inhibiting AVO’s ability to forecast eruptive activity (Coombs et al. 2018), though retrospective analysis of hydrophone data showed that weaker precursors were still often present (Tepp et al. 2019). Fewer events produced detectable lightning after event 40 on May 28 (Van Eaton et al. 2019). This second phase also included effusion of two short-lived subaerial lava domes.
"After a nine-week hiatus, Bogoslof erupted without detectable geophysical precursors on May 17 (event 39). This explosion lasted 200 min and produced an ash cloud that reached as high as 10 km asl and drifted south along the edge of a mass ofweather clouds, as seen in GOES satellite imagery (Schneider et al. 2019) and reported by pilots. Trace ashfall (< 0.8mm) was reported in Nikolski, Alaska, 123 km southwest of Bogoslof
(Fig. 1). As with ash samples from the previous two events, this one contains about 40 % free crystals, though the remainder of this sample is richer in juvenile scoria (as opposed to lithic fragments) than previous ones (Loewen et al. 2019).
"Following event 39, an oblique photo showed that the crater lake was breached with a 550-m wide gap along the north shore and that the northeast shore was extended by another 300 m from new tephra deposits (Fig. 5b). Eleven days after event 39, explosive event 40 occurred on May 28, also with no detected precursors. This eruption produced an ash cloud that rose to 10.1 km asl as shown in MODIS satellite images
(Schneider et al. 2019). The cloud drifted to the northeast and was reported by numerous pilots, including a report of 'sulfur' smell in cockpit from a plane about 800 km from Bogoslof. A Worldview-3 satellite image collected about 18 min after the start of the event shows the initial development of the eruption cloud (Fig. 4f; Waythomas et al. 2019a).
"These two explosive events, which occurred just after the hiatus, are among the most energetic of the eruptive sequence. They both produced appreciable SO2 clouds as detected in satellite data (9.4 and 7.7 kt; Lopez et al. 2019) and generated among the highest number of lightning strokes (647 and 719; Van Eaton et al. 2019; Fig. 8). The remnant SO2 cloud from event 40 on May 28 was still detectable over Hudson Bay, over 4000 km east of Bogoslof, on June 2. Of the 25 events analyzed by Haney et al. (2019a), the co-eruptive tremor of these two events had the highest reduced displacement of any in the sequence-both yield values of about 50 cm2, which is comparable to values calculated for eruption tremor from the largest eruptions in Alaska over the past 20 years (e.g., Redoubt in 2009; McNutt et al. 2013).
"Cosmo SkyMed radar imagery from May 31 shows a large portion of the north side of the island was removed during May 28 explosive activity, leaving a crescent-shaped bay, open to the north. This configuration of the island remained essentially intact through June 12 (Fig. 6i).
"As seen previously from a March 8 Landsat image, sometime following May 28, intense steaming recommenced from an area just southwest of the vent lagoon. This region, about 300 m in diameter, remained hot and emitting steam throughout the eruption and afterwards (Fig. 6i-l), and may have been the site of shallow magma intrusion or a filled-in vent area.
"Early June brought a series of small explosions and growth of a lava dome that breached sea level on June 5, and was then destroyed on June 10.
"Several hours after a swarm of very small earthquakes on May 31, event 41 was a 5-min long explosion that produced a small, water-rich cloud that reached as high as 7.3 km asl. Following this, cloudy weather prevented clear views of the volcano through June 4. A Sentinel 1-B SAR image from June 4 shows no dome in the crater lagoon (Fig. 7a). Midday on June 5, data derived from US National Imagery Systems indicate that a small protrusion of lava had breached water level immediately between the 1926-1927 and 1992 lava domes in northern portion of vent lagoon. By June 6, low-resolution satellite images show distinctly elevated surface temperatures at Bogoslof, suggesting that hot lava was at the surface (Fig. 8). Sentinel-1 SAR images show the growth of the dome from June 7 through June 9 (Fig. 7b,c). On June 7, data derived from US National Imagery Systems showed that the new dome was about 110 m in diameter. The dome was also seen in a COSMO SkyMed radar image from June 8 (Waythomas et al. 2019a; their Figure 15).
"During the interval of lava effusion, several small explosive events (42-47) occurred that did not disrupt the growing dome as shown by Sentinel-1 SAR data from June 9, which confirmed that dome was still there after event 47 (Fig. 7c). Several of the events (44, 45, and 47) have infrasound frequencies consistent with a subaerial vent (Fee et al. 2019).
"The June 5 lava dome was short-lived, as it was completely destroyed during a long, pulsatory explosive event on June 10 (event 48). This event started with discrete explosions detected on the Okmok infrasound array as early as 8:27 but intensifying from 11:18 to 11:38. Starting at about 12:16, activity transitioned into nearly continuous seismic and infrasound tremor signals for about 40 min. Shorter bursts of tremor continued
until 14:51, for an envelope of activity that lasted several hours. VIIRS satellite images of the resulting cloud showed it reached as high as 9.5 km asl and drifted to the northwest. Satellite data also indicated that at least part of the volcanic cloud was more ash-rich than many of those seen
previously in the Bogoslof eruptive sequence to date, suggesting that the eruption may have fragmented and incorporated the lava dome that was emplaced earlier that week (Schneider et al. 2019). This event generated 31 detected lightning strokes (Van Eaton et al. 2019).
"A Worldview-3 image from June 10, acquired after event 48, shows that the June 5 dome was no longer present (Waythomas et al. 2019a). Another, clearer Worldview-3 image from June 12 (Fig. 6i) showed ballistic blocks distributed uniformly around the island with the highest concentrations in the southeast and southwest sectors-likely remnants of the June 5 dome (Waythomas et al. 2019a). The FI of infrasound
from this event gradually decreases in the last hour of the event, suggesting a change from subaerial to submarine venting after the destruction of the lava dome (Fee et al. 2019; their Fig. 8).
"On June 13, event 49 comprised a series of four explosions that started at 01:44 and ended at about 04:34. Each pulse lasted between 10 and 30 min and generated volcanic clouds that rose to a maximum height of 3.8 km asl and dissipated within about 30 min. Residents of Unalaska/Dutch Harbor reported smelling sulfur, and winds were consistent with a source at Bogoslof. An additional 2-min long explosion was detected in seismic and infrasound data later on 13 June (event 50), with no detected ash cloud.
"There was an 11-day pause in detected explosive activity from June 13-24. During an overflight on June 22, sediment-laden water was visible in the open vent lagoon area, and the area of persistent steaming was visible just east of the December uplift area (Fig. 5c).
"Twelve explosive events occurred from June 24 to July 11 (events 51-62). These were generally short-duration, detected in seismic and infrasound data, and produced little or no lightning (Table 1). Several of these events were closely spaced groups of smaller events. A photo taken on July 3 shows the area of persistent steaming visible from behind the December uplifted block, but no activity at other areas of the island (Fig. 5d).
"Following an almost month-long pause, explosive activity resumed on August 7, with a 2-h long sequence (event 63; Table 1). Detected in seismic, infrasound, satellite, and lightning data, event 63 was longer lived than many of the events in the eruptive sequence and satellite images showed that ash from the eruption formed a continuous cloud that was carried by strong winds south over Umnak Island and then out over
the Pacific Ocean reaching an altitude of 10-12 km asl (Schneider et al. 2019). Event 63 produced one of the largest SO2 masses of the eruption, 5.8 kt, as determined by IASI satellite (Lopez et al. 2019). It also yielded the highest number of lightning strokes during the second half of the eruption (117; Van Eaton et al. 2019).
"As shown in aWorldview-2 image from August 8 (Fig. 6j), event 63 produced significant proximal tephra that expanded Bogoslof Island’s northern coastline and closed off the northfacing lagoon to create a crater lake in the vent region, perhaps even leading to a subaerial vent for some portion of this explosive event. This image also shows a large number of new ballistic blocks, primarily in the east-southeast sector of the island (Waythomas et al. 2019a, their Fig. 18). In infrasound data, event 63 shows a progression from low to high FI, consistent with a shift from submarine to subaerial venting (Fee et al. 2019).
"The final 2 weeks of the eruption were marked by mostly short-duration explosions and concurrent growth of a lava dome. Events 64 through 70 were mostly short-lived (6 min or less, except event 70 which lasted 59 min; Table 1), produced little or no lightning (Van Eaton et al. 2019), and modest SO2 (up to1.2 kt; Lopez et al. 2019). Volcanic clouds from the explosions rose to high altitudes (up to 8.7 km asl; Schneider et al. 2019) despite their short durations.
"A high-resolution Worldview-3 image on August 13 shows a vent region filled with seawater and no lava dome was apparent (Fig. 6k). On August 15, repeating low-frequency seismic events from Bogoslof were detected on Okmok and Makushin networks for about 8 h (Tepp et al. 2019). A photo from an overflight of the volcano on August 15 shows the area of persistent steaming visible since late May, but nothing at the site of the dome that would appear days later in the vent lagoon (Fig. 5e). If the August 15 seismicity was related to magma ascent, it had not yet risen shallowly enough to impact the vent lagoon area.
"A new lava dome was observed in data derived from US National Imagery Systems in the enclosed, water-filled crater on August 18 and grew to about 160 m in diameter and 20 m tall by August 22. A Sentinel SAR view shows the dome on August 20 (Fig. 7d). An oblique aerial photo taken on August 26 shows a vigorous steam plume that likely was generated as hot dome rock interacted with seawater in the vent lagoon area (Fig. 5f).
"SAR images from Sentinel-1 (Fig. 7e) and Cosmos SkyMed (Fig. 7f) on August 27, after event 66, suggest that most of this dome had been removed, with only some northern dome edge remnants remaining. The low-frequency infrasound associated with events 66-69 suggest that the vent was below water (Fee et al. 2019).
"Following the last explosive activity on August 30, there were a few earthquakes detected in seismic and hydrophone data (G. Tepp, written comm. 2019), but seismic activity quieted soon after. In August 2018, AVO added a telemetered seismometer on Bogoslof Island, which has recorded little activity of note.
"Weakly elevated surface temperatures were consistently observed at Bogoslof in low-resolution satellite images through November 2017. High-resolution satellite images from the fall of 2017 show steaming and discoloration on the island (e.g., Fig. 6l). As of 2019, continued erosion has changed the shape of the island (Waythomas et al. 2019b), similar to what occurred following previous eruptions."
"From December 12 through March 13, explosions occurred at a mean rate of once every 58 h (2.4 days). Many of the explosions during this period were preceded by repeating earthquakes that accelerated into an explosion, characterized by increasing magnitude and becoming closer together in time, described by Wech et al. (2018) as 'slow-clap' seismicity and also described in Tepp et al. (2019) and Tepp and Haney (2019). On the basis of T-phase character, Wech et al. (2018) interpret these as occurring in the shallow crust.
"Seismicity remained at fairly low levels in October and November. In early December, days before the first detected infrasound, earthquakes with weak T-phases again suggested mid- to shallow-crustal magma movement (Wech et al. 2018). On December 12, the first infrasound signal from Bogoslof marked the beginning of the eruption. The signal, later recognized as event 1, was accompanied by a weak seismic signal, but no cloud was observed in satellite images. Infrasound for event 2, later the same day, has a relatively high frequency index (FI; ratio of high-frequency to low-frequency infrasound), suggesting a subaerial vent (Fee et al. 2019). On December 14, AVO received an email report from St. George, 308 km north-northwest of Bogoslof, about intermittent sulfur smell, likely corresponding to activity at Bogoslof. A Sentinel-2 satellite image taken minutes after event 3 on December 14 captured intense steaming from a subaerial vent and new pyroclastic deposits on the island and suspended in the surrounding ocean (Fig. 4a). Events 4 and 5 occurred on December 16 and 19. These first five explosions were not detected in real time, only after retrospective analysis of data streams. Thus, we have no direct observations of the character of these explosions.
"Satellite imagery beginning December 14 shows that uplift of Bogoslof Island occurred and may have been associated with cryptodome emplacement. A Sentinel-2 satellite image from December 21 (Waythomas et al. 2019a) shows an approximately 300-m long oval-shaped raised mass just north of Castle Rock (a remnant lava dome from the 1796-1804 eruptive period; see Fig. 3). This feature was not present in a Sentinel-2 image from December 14 (Waythomas et al. 2019a; their Fig. 5a). Preliminary analysis of DEMs generated by stereo satellite pairs shows that this feature continued to grow throughout the eruption (A. Diefenbach, written comm. 2019).
"No elevated surface temperatures were seen in satellite monitoring checks at Bogoslof until January 19, and neither the uplifted block nor surrounding areas were visibly steaming in December or January in a way that would be consistent with lava effusion (Figs. 3 and 6). Samples of the material exposed along the steep, eastward face of the uplift (see Waythomas et al. 2019b) are trachyandesite lava with 58-60 wt% SiO2 and are a different composition than the dominant juvenile basalt magma erupted in 2016-2017 (Loewen et al. 2019). Given the lack of thermal signature, as well as the composition of this feature, we suggest that this uplifted feature is likely the roof above a shallow cryptodome.
"Several pilots observed a volcanic cloud in the vicinity of Bogoslof on December 21 (Fig. 4b), and were the first alert to AVO that Bogoslof had become active. A pilot later the same day reported seeing 'a new land mass' in the island cluster. This event, event 6, began a period of activity that lasted a little less than a month, with explosive events 6-22 occurring at a rate of about one every 40 h. They produced volcanic clouds of heights up to 11 km, with variable durations (2 to 102 min), and about half produced detected lightning (Table 1). Most (80 %) consisted of single seismic pulses.
"Some of the only direct observations of activity occurred during event 9 on December 23, when observers aboard a Coast Guard vessel in the area reported ash emissions, lightning, and the ejection of incandescent lava and fragmental material that lasted about an hour. The cloud from event 16 on January 5 rose to 11.8 km asl and was observed by numerous pilots and mariners (Fig. 4c).
"A Worldview-3 image from December 25 (Fig. 6b) shows a bilobate submarine vent area and new pyroclastic deposits enlarging the island and beginning to enclose a vent lagoon. On December 29, data derived from US National Imagery Systems indicated a nearly complete ring of pyroclastic deposits around a more circular, submerged, ~ 450-m-across vent area. On January 10, passengers on a helicopter that flew from Dutch Harbor to Bogoslof took photographs and video of the island that showed discolored and roiling water in the crescent-shaped vent area, and the area of uplift from December (Fig. 3b). A Worldview-3 image from January 11 (Fig. 6c) shows continued growth of the island, and abundant meter-scale ballistics on the north and south ends of the island (Waythomas et al. 2019a, their Fig. 7).
"Satellite images, pilot reports, and ground-based photos show that event 23 on January 18 was the first demonstrably ash-rich cloud of the eruption sequence. Previous explosions produced clouds that were white in color with almost no ash signal in satellite data (Schneider et al. 2019).
"Prior to event 23, as with many other explosions on the first half of the eruption, seismic stations on neighboring islands picked up precursory seismicity in the form of repeating earthquakes that became more closely spaced in time during the runup to the explosion (Tepp et al. 2019). These lasted for about 11 h. Infrasound data show that the explosion itself lasted about 80 min and was pulsatory (Lyons et al. 2019b), with seven discrete bursts of strong seismicity (Searcy and Power 2019). Despite the event’s duration, only modest lightning was produced (14 strokes; Van Eaton et al. 2019).
"Pilots reports, visual satellite images, and thewest-facing FAA web camera in Dutch Harbor (Fig. 4d) indicated that the explosion produced a dark-gray ash cloud. MODIS satellite images show the cloud rose as high as 8.5 kmasl before drifting northeast over the Alaska Peninsula. An ash signal in the brightness-temperature-difference (BTD) satellite retrieval was seen along the leading cloud edge, suggesting that the cloud interior may have been opaque (Schneider et al. 2019). This event produced 1.9 kt of SO2 and was the first since event 13 on December 31 to produce more than 0.2 kt SO2 (Lopez et al. 2019).
"A mid-infrared MODIS satellite image collected minutes after the explosion showed a possible "recovery pixel". These occur when the sensor encounters a very hot object and saturates, suggesting lava or hot tephra must have been present above the water surface (D. Schneider, written comm. 2017). These were the first elevated surface temperatures detected by satellite imagery of the eruption. Clouds moved in to obscure the volcano soon after, with no additional views prior to January 20. Because event 23 was not detected on the Okmok infrasound array, we do not have infrasound FI analysis for this event, which for other events provides information on subaerial versus submarine venting (Fee et al. 2019).
"In the week following event 23, five explosions (events 24-28) occurred with an average repose time of 42 h between them (Table 1, Fig. 8). These events had total infrasound durations of 3-15 min, produced modest lightning, observable volcanic clouds, and each up to 0.6 kt of SO2 (Table 1). None showed a clear ash signature in satellite data.
"A Worldview-2 image acquired about 10 h after event 26 shows the island with a lagoon, open to the east, with two circular craters. The one to the northwest had upwelling within it, suggesting it was above the vent for the event 26 explosion (Waythomas et al. 2019a, their Fig. 8).
"About 84 h after event 28, the longest sustained explosion of the eruptive sequence produced significant ash and resulted dramatic changes to Bogoslof Island. Event 29 comprised more than 10 short-duration explosions that were detected in seismic, infrasound, and lightning data, took place over several hours on January 31, and produced several discrete volcanic clouds.
"The event started with no detected precursors, and activity escalated from 08:40 to 09:30, as indicated by increased seismic tremor and high amplitude infrasound signals. At 09:00, a continuous volcanic plume extended for a distance of more than 200 km towards the east-southeast over Unalaska Island at an altitude of 5.9 km asl. Event 29 produced 190 lightning strokes (Table 1; Van Eaton et al. 2019) and the most significant SO2 emission since December 22, 2016 (3.6 kt; Lopez et al. 2019).
"Tephra accumulation at the vent produced a demonstrably dry volcanic edifice for the first time during event 29. Data derived from US National Imagery Systems shortly after the event showed light steaming from an apparently dry eruption crater about 400 m in diameter and as much as 100 m deep below the west crater rim. Whereas most previous explosive events in the sequence, with the possible exception of event 23 on January 18, issued from a vent in shallow seawater, freshly erupted tephra formed an almost 200-m-wide barrier separating the vent from the sea. A Worldview-3 image from about 15 h later the same day (Fig. 6d) shows that the crater had already begun to fill with seawater. As with several of the events, large ballistic blocks were visible along the island’s north southwest shoreline (Waythomas et al. 2019a, their Fig. 9).
"Event 29 resulted in ashfall on Unalaska Island including trace (< 0.8 mm) amounts in the community of Dutch Harbor/ Unalaska. A sample of ash collected in Dutch Harbor comprises free crystals of plagioclase, clinopyroxene, amphibole, and rare biotite, as well as particles that display a range of groundmass textures from microlitic to glassy, and that vary from dense to vesicular (Loewen et al. 2019). The material is consistent with being a mixture of juvenile basalt scoria and non-juvenile lithics.
"Following event 29, a series of smaller explosive events occurred from February 3 to 20 (events 30-36; Table 1). During this period, the inter-event times became more variable, with some pauses of up to 9 days between events. Explosions during this time lasted minutes to a few tens of minutes, produced clouds that rose from 4.6 to 8.6 km asl (Schneider et al. 2019), 0-92 strokes of lightning (Van Eaton et al. 2019), and modest SO2 (0-1.4 kt; Lopez et al. 2019).
"A series of satellite images from January 31 through February 12 shows little change in the island’s morphology after event 29 (Fig. 6d-e; Waythomas et al. 2019a). Elevated surface temperatures detected in two MODIS images from February 6 likely reflected hot new deposits from event 31 on February 4. A high-resolution Worldview-2 satellite image from February 23 also shows little change except for the presence of ballistics particles ejected during events 32-36 (February 13-20) and distributed across the island (Waythomas et al. 2019a). A clear view from March 3 similarly shows only minor changes (Fig. 6f).
"The final event in this time interval, event 36 on February 20, was an excellent example of a Bogoslof explosion with a precursory seismic sequence (see Fig. 4 of Coombs et al. 2018). A classic sequence of coalescing earthquakes served as a prelude to the series of energetic eruptive signals that made up the event. Earthquakes were first detected at 20:42 on February 19. The sequence then maintained a relatively low rate until about 00:55 (February 20) when the rate suddenly increased to about 30 earthquakes per hour. The rate then progressively increased over the next hour almost merging to tremor by 2:00. Earthquakes ceased at 2:07 and after a1-min break transitioned to tremor. The eruptive signals consisted of about 9 blasts that were captured on multiple infrasound arrays resulting in a 40-min long explosion. The resulting plume reached 6.1 km asl and was elongated, stretching to the east-southeast over Unalaska Island. Pilots and observers on Unalaska Island at the time clearly observed the white, ice-rich cloud (Fig. 4e).
"After a 16-day pause, event 37 on March 8 lasted 200 min. It had the largest infrasound energy (Lyons et al. 2019a), seismic tremor magnitude (Tepp et al. 2019), most lightning (1437 strokes; Van Eaton et al. 2019), largest SO2 emission (21.5 kt; Lopez et al. 2019), and most significant ash cloud (Schneider et al. 2019) of any event in the eruptive sequence (though not the highest reduced displacement; Haney et al. 2019a). VIIRS satellite images showed the resulting cloud reached between 10.6 and 13.4 km asl and drifted east over Unalaska Island. Minor ashfall of a few millimeters was reported by a mariner near Cape Kovrizkha (northwest Unalaska Island; Fig. 1) who collected ash from his vessel. Like the ash sample from January 31, this ash contains particles of juvenile basaltic scoria and free crystals with minor amounts of what appear to be volcanic lithics (Loewen et al. 2019). A barely perceptible ashfall deposit was reported at Unalaska/Dutch Harbor.
"Event 37 also changed the shape of the island and temporarily dried out the vent area, as seen in a Landsat-8 image from March 8 (not shown). In infrasound data, event 37 shows a mix of low and high FI, consistent with an eruption from both submarine and subaerial vent(s) during this event (Fee et al. 2019).
"A March 11 WorldView-3 image (Fig. 6g) shows the west coast of the island grew significantly since March 3 (Fig 6f), with about 250m of new land west of the 1926-1927 dome. A new ~ 150-m wide vent was also observed on the north coast of the island, and ballistics ejecta clustered on the eastern side of the island (Waythomas et al. 2019a, their Fig. 11).
"On March 10 and 11, two multi-hour seismic swarms each produced hundreds of earthquakes as detected on station MAPS (Tepp et al. 2019), but neither led directly to an explosion. A few hours later, a precursory swarm (Tepp et al. 2019) began on March 11 and culminated on March 13 in event 38. This event produced a small cloud that reached as high as 4.1 km asl and drifted south-southwest.
"Following event 38 on March 13, there was a 9-week pause in explosive activity at Bogoslof. The only detected unrest observed during the hiatus was a swarm of volcano-tectonic earthquakes on April 15. The swarm lasted for several hours, comprised 118 detected earthquakes (catalog of Wech et al. 2018) with magnitudes between ~ 0.8 and 2.2, and is interpreted to reflect magmatic intrusion in the mid to upper crust because of the earthquakes’ weak T-phases (Wech et al. 2018).
"Satellite images from this period show the rapid surface reworking and erosion of new volcanic deposits on Bogoslof Island and coastline erosion by wave action (Waythomas et al. 2019a). Photos (Fig. 5a) and a Worldview-3 image from May 11 (Fig. 6h) show that the vent lagoon remained hot throughout the hiatus, evidenced by steam rising from the crater lagoon.
"From May 16 through August 30, AVO detected 32 explosive events at the volcano. In contrast to the events of December 2016-March 2017, few of the explosions in the later phase were preceded by detectable seismic precursors, inhibiting AVO’s ability to forecast eruptive activity (Coombs et al. 2018), though retrospective analysis of hydrophone data showed that weaker precursors were still often present (Tepp et al. 2019). Fewer events produced detectable lightning after event 40 on May 28 (Van Eaton et al. 2019). This second phase also included effusion of two short-lived subaerial lava domes.
"After a nine-week hiatus, Bogoslof erupted without detectable geophysical precursors on May 17 (event 39). This explosion lasted 200 min and produced an ash cloud that reached as high as 10 km asl and drifted south along the edge of a mass ofweather clouds, as seen in GOES satellite imagery (Schneider et al. 2019) and reported by pilots. Trace ashfall (< 0.8mm) was reported in Nikolski, Alaska, 123 km southwest of Bogoslof
(Fig. 1). As with ash samples from the previous two events, this one contains about 40 % free crystals, though the remainder of this sample is richer in juvenile scoria (as opposed to lithic fragments) than previous ones (Loewen et al. 2019).
"Following event 39, an oblique photo showed that the crater lake was breached with a 550-m wide gap along the north shore and that the northeast shore was extended by another 300 m from new tephra deposits (Fig. 5b). Eleven days after event 39, explosive event 40 occurred on May 28, also with no detected precursors. This eruption produced an ash cloud that rose to 10.1 km asl as shown in MODIS satellite images
(Schneider et al. 2019). The cloud drifted to the northeast and was reported by numerous pilots, including a report of 'sulfur' smell in cockpit from a plane about 800 km from Bogoslof. A Worldview-3 satellite image collected about 18 min after the start of the event shows the initial development of the eruption cloud (Fig. 4f; Waythomas et al. 2019a).
"These two explosive events, which occurred just after the hiatus, are among the most energetic of the eruptive sequence. They both produced appreciable SO2 clouds as detected in satellite data (9.4 and 7.7 kt; Lopez et al. 2019) and generated among the highest number of lightning strokes (647 and 719; Van Eaton et al. 2019; Fig. 8). The remnant SO2 cloud from event 40 on May 28 was still detectable over Hudson Bay, over 4000 km east of Bogoslof, on June 2. Of the 25 events analyzed by Haney et al. (2019a), the co-eruptive tremor of these two events had the highest reduced displacement of any in the sequence-both yield values of about 50 cm2, which is comparable to values calculated for eruption tremor from the largest eruptions in Alaska over the past 20 years (e.g., Redoubt in 2009; McNutt et al. 2013).
"Cosmo SkyMed radar imagery from May 31 shows a large portion of the north side of the island was removed during May 28 explosive activity, leaving a crescent-shaped bay, open to the north. This configuration of the island remained essentially intact through June 12 (Fig. 6i).
"As seen previously from a March 8 Landsat image, sometime following May 28, intense steaming recommenced from an area just southwest of the vent lagoon. This region, about 300 m in diameter, remained hot and emitting steam throughout the eruption and afterwards (Fig. 6i-l), and may have been the site of shallow magma intrusion or a filled-in vent area.
"Early June brought a series of small explosions and growth of a lava dome that breached sea level on June 5, and was then destroyed on June 10.
"Several hours after a swarm of very small earthquakes on May 31, event 41 was a 5-min long explosion that produced a small, water-rich cloud that reached as high as 7.3 km asl. Following this, cloudy weather prevented clear views of the volcano through June 4. A Sentinel 1-B SAR image from June 4 shows no dome in the crater lagoon (Fig. 7a). Midday on June 5, data derived from US National Imagery Systems indicate that a small protrusion of lava had breached water level immediately between the 1926-1927 and 1992 lava domes in northern portion of vent lagoon. By June 6, low-resolution satellite images show distinctly elevated surface temperatures at Bogoslof, suggesting that hot lava was at the surface (Fig. 8). Sentinel-1 SAR images show the growth of the dome from June 7 through June 9 (Fig. 7b,c). On June 7, data derived from US National Imagery Systems showed that the new dome was about 110 m in diameter. The dome was also seen in a COSMO SkyMed radar image from June 8 (Waythomas et al. 2019a; their Figure 15).
"During the interval of lava effusion, several small explosive events (42-47) occurred that did not disrupt the growing dome as shown by Sentinel-1 SAR data from June 9, which confirmed that dome was still there after event 47 (Fig. 7c). Several of the events (44, 45, and 47) have infrasound frequencies consistent with a subaerial vent (Fee et al. 2019).
"The June 5 lava dome was short-lived, as it was completely destroyed during a long, pulsatory explosive event on June 10 (event 48). This event started with discrete explosions detected on the Okmok infrasound array as early as 8:27 but intensifying from 11:18 to 11:38. Starting at about 12:16, activity transitioned into nearly continuous seismic and infrasound tremor signals for about 40 min. Shorter bursts of tremor continued
until 14:51, for an envelope of activity that lasted several hours. VIIRS satellite images of the resulting cloud showed it reached as high as 9.5 km asl and drifted to the northwest. Satellite data also indicated that at least part of the volcanic cloud was more ash-rich than many of those seen
previously in the Bogoslof eruptive sequence to date, suggesting that the eruption may have fragmented and incorporated the lava dome that was emplaced earlier that week (Schneider et al. 2019). This event generated 31 detected lightning strokes (Van Eaton et al. 2019).
"A Worldview-3 image from June 10, acquired after event 48, shows that the June 5 dome was no longer present (Waythomas et al. 2019a). Another, clearer Worldview-3 image from June 12 (Fig. 6i) showed ballistic blocks distributed uniformly around the island with the highest concentrations in the southeast and southwest sectors-likely remnants of the June 5 dome (Waythomas et al. 2019a). The FI of infrasound
from this event gradually decreases in the last hour of the event, suggesting a change from subaerial to submarine venting after the destruction of the lava dome (Fee et al. 2019; their Fig. 8).
"On June 13, event 49 comprised a series of four explosions that started at 01:44 and ended at about 04:34. Each pulse lasted between 10 and 30 min and generated volcanic clouds that rose to a maximum height of 3.8 km asl and dissipated within about 30 min. Residents of Unalaska/Dutch Harbor reported smelling sulfur, and winds were consistent with a source at Bogoslof. An additional 2-min long explosion was detected in seismic and infrasound data later on 13 June (event 50), with no detected ash cloud.
"There was an 11-day pause in detected explosive activity from June 13-24. During an overflight on June 22, sediment-laden water was visible in the open vent lagoon area, and the area of persistent steaming was visible just east of the December uplift area (Fig. 5c).
"Twelve explosive events occurred from June 24 to July 11 (events 51-62). These were generally short-duration, detected in seismic and infrasound data, and produced little or no lightning (Table 1). Several of these events were closely spaced groups of smaller events. A photo taken on July 3 shows the area of persistent steaming visible from behind the December uplifted block, but no activity at other areas of the island (Fig. 5d).
"Following an almost month-long pause, explosive activity resumed on August 7, with a 2-h long sequence (event 63; Table 1). Detected in seismic, infrasound, satellite, and lightning data, event 63 was longer lived than many of the events in the eruptive sequence and satellite images showed that ash from the eruption formed a continuous cloud that was carried by strong winds south over Umnak Island and then out over
the Pacific Ocean reaching an altitude of 10-12 km asl (Schneider et al. 2019). Event 63 produced one of the largest SO2 masses of the eruption, 5.8 kt, as determined by IASI satellite (Lopez et al. 2019). It also yielded the highest number of lightning strokes during the second half of the eruption (117; Van Eaton et al. 2019).
"As shown in aWorldview-2 image from August 8 (Fig. 6j), event 63 produced significant proximal tephra that expanded Bogoslof Island’s northern coastline and closed off the northfacing lagoon to create a crater lake in the vent region, perhaps even leading to a subaerial vent for some portion of this explosive event. This image also shows a large number of new ballistic blocks, primarily in the east-southeast sector of the island (Waythomas et al. 2019a, their Fig. 18). In infrasound data, event 63 shows a progression from low to high FI, consistent with a shift from submarine to subaerial venting (Fee et al. 2019).
"The final 2 weeks of the eruption were marked by mostly short-duration explosions and concurrent growth of a lava dome. Events 64 through 70 were mostly short-lived (6 min or less, except event 70 which lasted 59 min; Table 1), produced little or no lightning (Van Eaton et al. 2019), and modest SO2 (up to1.2 kt; Lopez et al. 2019). Volcanic clouds from the explosions rose to high altitudes (up to 8.7 km asl; Schneider et al. 2019) despite their short durations.
"A high-resolution Worldview-3 image on August 13 shows a vent region filled with seawater and no lava dome was apparent (Fig. 6k). On August 15, repeating low-frequency seismic events from Bogoslof were detected on Okmok and Makushin networks for about 8 h (Tepp et al. 2019). A photo from an overflight of the volcano on August 15 shows the area of persistent steaming visible since late May, but nothing at the site of the dome that would appear days later in the vent lagoon (Fig. 5e). If the August 15 seismicity was related to magma ascent, it had not yet risen shallowly enough to impact the vent lagoon area.
"A new lava dome was observed in data derived from US National Imagery Systems in the enclosed, water-filled crater on August 18 and grew to about 160 m in diameter and 20 m tall by August 22. A Sentinel SAR view shows the dome on August 20 (Fig. 7d). An oblique aerial photo taken on August 26 shows a vigorous steam plume that likely was generated as hot dome rock interacted with seawater in the vent lagoon area (Fig. 5f).
"SAR images from Sentinel-1 (Fig. 7e) and Cosmos SkyMed (Fig. 7f) on August 27, after event 66, suggest that most of this dome had been removed, with only some northern dome edge remnants remaining. The low-frequency infrasound associated with events 66-69 suggest that the vent was below water (Fee et al. 2019).
"Following the last explosive activity on August 30, there were a few earthquakes detected in seismic and hydrophone data (G. Tepp, written comm. 2019), but seismic activity quieted soon after. In August 2018, AVO added a telemetered seismometer on Bogoslof Island, which has recorded little activity of note.
"Weakly elevated surface temperatures were consistently observed at Bogoslof in low-resolution satellite images through November 2017. High-resolution satellite images from the fall of 2017 show steaming and discoloration on the island (e.g., Fig. 6l). As of 2019, continued erosion has changed the shape of the island (Waythomas et al. 2019b), similar to what occurred following previous eruptions."
Impact: Alaska Dispatch News reported on the January 30-31, 2017 eruption: "An hours-long eruption of Bogoslof volcano in the Aleutian Islands dropped a small amount of ash on nearby Unalaska overnight Tuesday from a massive plume that drifted over the Pacific Ocean.
Laura Kraegel, a reporter at Unalaska public radio station KUCB, said Tuesday morning that ash from the eruption wasn't easily visible in town.
"It's less than a millimeter but there's a sulfurous smell, so it's definitely apparent," Kraegel said.
Kristi Wallace, a geologist at the Alaska Volcano Observatory, said locals were sending photos of the ashfall, which was still considered "trace" because it hadn't exceeded a millimeter.
"I would not describe it as a continuous layer, so when it falls on snow you can see the snow in between and when it falls on cars it appears as droplets," Wallace said. "I don't think what they got is anything anyone could take out a ruler and measure."
The National Weather Service's Anchorage office received reports of trace ashfall in Unalaska from the plume by Tuesday morning. Joshua Maloy, an aviation meteorologist at the office, said the eruption, which began at 8:20 p.m. Monday according to the Alaska Volcano Observatory, had apparently ended by 3 a.m. Tuesday (https://www.adn.com/alaska-news/environment/2017/01/31/unalaska-receives-ashfall-after-bogoslof-eruption/)." Trace ashfall occurred in Nikolski on May 16 AKDT as a result on an eruption and on June 12 AKDT, residents of Unalaska/Dutch Harbor reported smelling sulfur, and winds were consistent with a source at Bogoslof. [5] [4] [6]
Aircraft Impact: The National Weather Service CWSU noted a partial list of flight impacts: on Dec 20 and 21, flights were moved out of the path of a potential ash cloud. About 50 flights were impacted by North Pacific flight changes due to the January 18 explosion. Smaller planes en route to Dutch Harbor were diverted, and at least three flights returned to the airport they originated from. Some local carriers cancelled flights to the area. On January 30 and 31, the Dutch Harbor airport received a minor amount of ashfall, and the runways, taxiways, and ramps could not be used until ash was removed, impacting at least three flights. An article featured on Earth, The Science Behind the Headlines reported that "On January 11, 2017, a flight from Tokyo to Minneapolis was rerouted southward due to low-level ash emissions from Bogoslof Volcano in the Aleutian Islands. Although no significant eruption occurred, the plane continued along the modified flight path rather than risk rerouting midflight in the event of increased volcanic activity" (https://www.earthmagazine.org/article/airplanes-and-ash-clouds-what-weve-learned-eyjafjallaj%C3%B6kull). The Alaska Dispatch News reported: "Robert Easton, an aviation forecaster with the National Weather Service's Alaska Aviation Weather Unit in Anchorage said, "It [Bogoslof's January 18, 2017 ash plume] has been affecting flights all night," Easton said. "At least three or four were affected at the minimum." Dave Barber, another forecaster at the weather unit, said forecasters were able to track pilots diverting around the ash cloud while the advisory was in effect. "We could see on plots of aircraft flight locations that they were avoiding the area, fortunately," Barber said (https://www.adn.com/alaska-news/aviation/2017/01/19/another-bogoslof-eruption-sends-ash-over-alaska-peninsula-kodiak-island/)." The Alaska Dispatch News reported on the January 30-31, 2017 eruption of Bogoslof: "About a dozen flights to or from Unalaska over the past 10 days had been canceled due to previous ashfall in the region, according to Shockley [Jennifer Shockley, Unalaska Department of Public Safety deputy director] (https://www.adn.com/alaska-news/environment/2017/01/31/unalaska-receives-ashfall-after-bogoslof-eruption/)." KUBC KIAL Unalaska Community Broadcasting reported that PenAir had cancelled Unalaska's midday flight due to the January 30-31, 2017 eruption (http://kucb.org/post/volcanic-ash-falls-unalaska-bogoslofs-longest-eruption-yet). Articles on Loadstar and Asia Fruit websites reported that Bogoslof ash clouds affected air travel, stating that "Asia-to-US airfreight capacity is tight after a series of volcanic eruptions in Alaska triggered an ash cloud that caused a number of flight cancellations" (http://www.fruitnet.com/asiafruit/article/172636/volcanic-ash). [7] [4] [6] [8] [9] [10]
Images
References Cited
[1] Alaska Volcano Observatory website, 2005
Alaska Volcano Observatory, 2005-, Alaska Volcano Observatory website: http://www.avo.alaska.edu.[2] Overview, chronology, and impacts of the 2016-2017 eruption of Bogoslof volcano, Alaska, 2019
Coombs, Michelle, Wallace, Kristi, Cameron, Cheryl, Lyons, John, Wech, Aaron, Angeli, Kim, and Cervelli, Peter, 2019, Overview, chronology, and impacts of the 2016-2017 eruption of Bogoslof volcano, Alaska: Bulletin of Volcanology, v, 81, n. 62, doi:10.1007/s00445-019-1322-9.[3] Volcanoes of the World, 2013
Global Volcanism Program, 2013, Volcanoes of the World, v. 4.5.3. Venzke, E (ed.): Smithsonian Institution. Downloaded 2017. http://dx.doi.org/10.5479/si.GVP.VOTW4-2013[4] Ash falls in Unalaska after Bogoslof eruption, 2017
Associated Press, 2017, Ash falls in Unalaska after Bogoslof eruption: Alaska Dispatch News article published online January 31, 2017, available at https://www.adn.com/alaska-news/environment/2017/01/31/unalaska-receives-ashfall-after-bogoslof-eruption/[5] Alaska volcano erupts; ash trace reaches city, 2017
Associated Press, 2017, Alaska volcano erupts; ash trace reaches city: Fox News article published online January 31, 2017, available at http://www.foxnews.com/us/2017/01/31/alaska-volcano-erupts-ash-trace-reaches-city.html[6] Volcanic ash falls on unalaska in Bogoslof's longest eruption yet, 2017
Associated Press, 2017, Volcanic ash falls on unalaska in Bogoslof's longest eruption yet: KUBC KIAL Unalaska Community Broadcasting article published online January 31, 2017, available at http://kucb.org/post/volcanic-ash-falls-unalaska-bogoslofs-longest-eruption-yet[7] Another Bogoslof eruption sends ash over Alaska Peninsula, Kodiak Island, 2017
Associated Press, 2017, Another Bogoslof eruption sends ash over Alaska Peninsula, Kodiak Island: Anchorage Daily News article published online January 19, 2017, available at https://www.adn.com/alaska-news/aviation/2017/01/19/another-bogoslof-eruption-sends-ash-over-alaska-peninsula-kodiak-island/
[8] Of airplanes and ash clouds: What we've learned since Eyjafjallajökull, 2017
Morton, Mary Caperton, 2017, Of airplanes and ash clouds: What we've learned since Eyjafjallajökull: Earth, The Science Behind the Headlines article published online April 2, 2017, available online at https://www.earthmagazine.org/article/airplanes-and-ash-clouds-what-weve-learned-eyjafjallaj%C3%B6kull[9] Ash cloud restricts Asia-US airfreight, 2017
Cheshire, L., 2017, Ash cloud restricts Asia-US airfreight: Asia Fruit article published online June 27, 2017, available at http://www.fruitnet.com/asiafruit/article/172636/volcanic-ash[10] Air freight shippers hit as volcanic ash plume hits transpacific capacity, 2017
Lennane, A., 2017, Air freight shippers hit as volcanic ash plume hits transpacific capacity: Loadstar article published online June 26, 2017, available at https://theloadstar.co.uk/air-freight-shippers-hit-volcanic-ash-plume-hits-transpacific-capacity/Complete Eruption References
Alaska Volcano Observatory website, 2005
Alaska Volcano Observatory, 2005-, Alaska Volcano Observatory website: http://www.avo.alaska.edu.
Another Bogoslof eruption sends ash over Alaska Peninsula, Kodiak Island, 2017
Associated Press, 2017, Another Bogoslof eruption sends ash over Alaska Peninsula, Kodiak Island: Anchorage Daily News article published online January 19, 2017, available at https://www.adn.com/alaska-news/aviation/2017/01/19/another-bogoslof-eruption-sends-ash-over-alaska-peninsula-kodiak-island/
Alaska volcano erupts; ash trace reaches city, 2017
Associated Press, 2017, Alaska volcano erupts; ash trace reaches city: Fox News article published online January 31, 2017, available at http://www.foxnews.com/us/2017/01/31/alaska-volcano-erupts-ash-trace-reaches-city.html
Ash falls in Unalaska after Bogoslof eruption, 2017
Associated Press, 2017, Ash falls in Unalaska after Bogoslof eruption: Alaska Dispatch News article published online January 31, 2017, available at https://www.adn.com/alaska-news/environment/2017/01/31/unalaska-receives-ashfall-after-bogoslof-eruption/
Volcanic ash falls on unalaska in Bogoslof's longest eruption yet, 2017
Associated Press, 2017, Volcanic ash falls on unalaska in Bogoslof's longest eruption yet: KUBC KIAL Unalaska Community Broadcasting article published online January 31, 2017, available at http://kucb.org/post/volcanic-ash-falls-unalaska-bogoslofs-longest-eruption-yet
Of airplanes and ash clouds: What we've learned since Eyjafjallajökull, 2017
Morton, Mary Caperton, 2017, Of airplanes and ash clouds: What we've learned since Eyjafjallajökull: Earth, The Science Behind the Headlines article published online April 2, 2017, available online at https://www.earthmagazine.org/article/airplanes-and-ash-clouds-what-weve-learned-eyjafjallaj%C3%B6kull
Bogoslof Volcano, Alaska: ongoing eruption through the Bering Sea, 2017
HVO, 2017, Bogoslof Volcano, Alaska: ongoing eruption through the Bering Sea: HVO Volcano Watch article published online March 30, 2017, available online at https://hvo.wr.usgs.gov/volcanowatch/view.php?id=956
2 Alaska volcanoes erupt just hours apart, 2017
Associated Press, 2017, 2 Alaska volcanoes erupt just hours apart: Anchorage Daily News article published online May 17, 2017, available at https://www.adn.com/alaska-news/science/2017/05/17/2-alaska-volcanoes-erupt-just-hours-apart/
Volcanic Explosions Rock an Alaskan Island as Etna Rumbles, 2017
Klemetti, E., 2017, Volcanic Explosions Rock an Alaskan Island as Etna Rumbles: Wired article published online May 19, 2017, available at https://www.wired.com/2017/05/volcanic-explosions-rock-alaskan-island-etna-rumbles/
‘Unpredictable’ Bogoslof Volcano erupts - again, 2017
Associated Press, 2017, ‘Unpredictable’ Bogoslof Volcano erupts - again: KTVA Alaska article published online May 16, 2017, available at http://www.ktva.com/gallery-unpredictable-bogoslof-volcano-captured-camera-340/
Three Alaska Peninsula volcanoes are restless, 2017
Lill, A., 2017, Three Alaska Peninsula volcanoes are restless: KDLG Dillingham, Alaska article published online June 9, 2017, available at http://kdlg.org/post/three-alaska-peninsula-volcanoes-are-restless#stream/0
Alaskan volcano spews plumes of ash into the Bering Sea in breathtaking new image captured by NASA satellite, 2017
Liberator, S., 2017, Alaskan volcano spews plumes of ash into the Bering Sea in breathtaking new image captured by NASA satellite: Daily Mail article published online June 9, 2017, available at http://www.dailymail.co.uk/sciencetech/article-4590148/NASA-releases-image-volcano-plume-seen-space.html
Alaska volcano erupts again, forcing new aviation alert, 2017
Associated Press, 2017, Alaska volcano erupts again, forcing new aviation alert: CBS News article published online May 30, 2017, available at http://www.cbsnews.com/news/alaska-volcano-bogoslof-erupts-again-aviation-alert-raised/
Story Time w/ Aunt Phil: Bogoslof Volcano, 2017
Bill, L. D., 2017, Story Time w/ Aunt Phil: Bogoslof Volcano: KTVA Alaska article published online June 12, 2017, available at http://www.ktva.com/story-time-w-aunt-phil-bogoslof-volcano-495/
Ask the Experts: Alaska’s Bogoslof Volcano Erupted Again-Why Was It So Hard to Predict?, 2017
Harris, M., 2017, Ask the Experts: Alaska’s Bogoslof Volcano Erupted Again-Why Was It So Hard to Predict?: Scientific American article published online May 31, 2017, available at https://www.scientificamerican.com/article/ask-the-experts-alaska-rsquo-s-bogoslof-volcano-erupted-again-mdash-why-was-it-so-hard-to-predict/
Island-Altering Eruption of Alaska's Bogoslof Volcano Seen in Images from Space, 2017
Breslin, S., 2017, Island-Altering Eruption of Alaska's Bogoslof Volcano Seen in Images from Space: The Weather Channel article published online June 8, 2017, available at https://weather.com/news/news/bogoslof-volcano-eruption-photos-digitalglobe-alaska
Alaska's Bogoslof Volcano Sees Pulses of Short Eruptions, 2017
Associated Press, 2017, Alaska's Bogoslof Volcano Sees Pulses of Short Eruptions: U.S. News & World Report article published online June 13, 2017, available at https://www.usnews.com/news/best-states/alaska/articles/2017-06-13/alaskas-bogoslof-volcano-sees-pulses-of-short-eruptions
Bogoslof volcano news & activity updates: Bogoslof volcano (Aleutian Islands): new series of larger explosions, 2017
Unknown, 2017, Bogoslof volcano news & activity updates: Bogoslof volcano (Aleutian Islands): new series of larger explosions: Volcano Discovery article published online June 13, 2017, available at https://www.volcanodiscovery.com/bogoslof/news/63661/Bogoslof-volcano-Aleutian-Islands-new-series-of-larger-explosions.html
Lightning network helps confirm volcanic eruption, 2017
Frey, M., 2017, Lightning network helps confirm volcanic eruption: KTVA article published online May 30, 2017, available at http://www.ktva.com/lightning-network-helps-confirm-volcanic-eruption-243/
Pretty Volcanic Plume Seen in Space Image, 2017
Pappas, S., 2017, Pretty Volcanic Plume Seen in Space Image: Live Science article published online June 9, 2017, available at https://www.livescience.com/59425-bogoslof-volcanic-plume-space-image.html
Scientist says Bogoslof has history of eruptive sequences, 2017
Associated Press, 2017, Scientist says Bogoslof has history of eruptive sequences: KTUU article published online May 21, 2017, available at http://www.ktuu.com/content/news/Sc-423570894.html
NASA Shares Beautiful Image Of Volcanic Eruption Aftermath As Seen From Space, 2017
Associated Press, 2017, NASA Shares Beautiful Image Of Volcanic Eruption Aftermath As Seen From Space: IFL Science article published online June 5, 2017, available at http://www.iflscience.com/environment/nasa-shares-beautiful-image-of-volcanic-eruption-aftermath-as-seen-from-space/
Photographs show how Alaska volcano's eruptions have changed island, 2017
Associated Press, 2017, Photographs show how Alaska volcano's eruptions have changed island: CBS News article published online January 12, 2017, available at http://www.cbsnews.com/news/bogoslof-island-alaska-eruptions-photographs/
With Bogoslof volcano's continuing eruptions, island has tripled in size, 2017
Andrews, L., 2017, With Bogoslof volcano's continuing eruptions, island has tripled in size: ADN article published online February 18, 2017, available at https://www.adn.com/alaska-news/2017/02/18/with-bogoslof-volcanos-continuing-eruptions-island-has-tripled-in-size/
Blowing its top: an explanation of Bogoslof Volcano's eruptions, latest on Thursday, 2017
Winkle, K., 2017, Blowing its top: an explanation of Bogoslof Volcano's eruptions, latest on Thursday: KTUU article published online January 5, 2017, available at http://www.ktuu.com/content/news/Bogoslof-Volcano-erupts-a-409836685.html
Bogoslof Volcano In Alaska Erupts Spewing Ash Clouds, 2017
Gordon, A., 2017, Bogoslof Volcano In Alaska Erupts Spewing Ash Clouds: Tech Times article published online March 14, 2017, available at http://www.techtimes.com/articles/201539/20170314/bogoslof-volcano-in-alaska-erupts-spewing-ash-clouds.htm
An Alaskan Volcano Erupts, Largely Out of View, 2016
Fountain, H., 2017, An Alaskan Volcano Erupts, Largely Out of View: The New York Times article published online December 30, 2016, available at https://www.nytimes.com/2016/12/30/science/an-alaskan-volcano-bogoslof-erupts-largely-out-of-view.html?_r=0
Bogoslof volcano just erupted again, 2016
Zak, A., 2017, Bogoslof volcano just erupted again: ADN article published online December 31, 2016, available at https://www.adn.com/alaska-news/science/2016/12/31/aviators-in-the-aleutians-be-on-alert-bogoslof-volcano-just-erupted-again/
Bogoslof volcano settles down after sending ash over Alaska Peninsula, Kodiak Island, 2017
Klint, C., 2017, Bogoslof volcano settles down after sending ash over Alaska Peninsula, Kodiak Island: ADN article published online January 19, 2017, available at https://www.adn.com/alaska-news/aviation/2017/01/19/another-bogoslof-eruption-sends-ash-over-alaska-peninsula-kodiak-island/
Explosion at Bogoslof Volcano prompts ninth aviation warning during weeks-long eruption, 2017
Mackintosh, C., 2017, Explosion at Bogoslof Volcano prompts ninth aviation warning during weeks-long eruption: KTUU article published online January 18, 2017, available at http://www.ktuu.com/content/news/Explosion-at-Bogoslof-Volcano-prompts-ninth-aviation-warning-since-eruption-began-411143435.html
Bogoslof Volcano in Alaska Unexpectedly Erupts, 2016
Klemetti, E., 2017, Bogoslof Volcano in Alaska Unexpectedly Erupts: Wired article published online December 21, 2016, available at https://www.wired.com/2016/12/bogoslof-volcano-alaska-unexpectedly-erupts/
Bogoslof volcano erupts again, sends up another ash plume, 2016
Klint, C., 2017, Bogoslof volcano erupts again, sends up another ash plume: ADN article published online December 23, 2016, available at https://www.adn.com/alaska-news/science/2016/12/23/bogoslof-volcano-erupts-again-sends-up-30000-foot-ash-plume/
No high-altitude ash from latest Bogoslof eruption, scientists say, 2017
Klint, C., 2017, No high-altitude ash from latest Bogoslof eruption, scientists say: ADN article published online February 13, 2017, available at https://www.adn.com/alaska-news/environment/2017/02/13/bogoslof-eruption-with-ash-cloud-likely-puts-scientists-on-alert/
Is Bogoslof Volcano done erupting?, 2017
Kraegel, L., 2017, Is Bogoslof Volcano done erupting?: Alaska Public Media article published online April 6, 2017, available at http://www.alaskapublic.org/2017/04/06/is-bogoslof-volcano-done-erupting/
Highest aviation alert level issued after Alaskan volcano erupts, 2017
McKirdy, E., and Sutton, J., 2017, Highest aviation alert level issued after Alaskan volcano erupts: CNN article published online May 29, 2017, available at http://www.cnn.com/2017/05/29/us/alaska-bogoslof-volcano-eruption/index.html
Alaska’s Bogoslof volcano explodes, 2017
Associated Press, 2017, Alaska’s Bogoslof volcano explodes: South China Morning Post article published online March 9, 2017, available at http://www.scmp.com/news/world/united-states-canada/article/2077271/alaskas-bogoslof-volcano-explodes
No major explosions at Bogoslof in over a month, researchers say, 2017
Mackintosh, C., 2017, No major explosions at Bogoslof in over a month, researchers say: KTUU article published online April 14, 2017, available at http://www.ktuu.com/content/news/No-major-explosions-at-Bogoslof-in-over-a-month-researchers-say-419514723.html
‘Explosive events’ rock Pacific Ocean, 2017
Palin, M., 2017, ‘Explosive events’ rock Pacific Ocean: News.com article published online March 20, 2017, available at http://www.news.com.au/technology/environment/natural-wonders/explosive-events-rock-pacific-ocean/news-story/618b9ee04ece0d80e69c02ebe5c92d94
Not All Eruptions Are Equal For Submarine Bogoslof Volcano, 2017
Kraegel, L., 2017, Not All Eruptions Are Equal For Submarine Bogoslof Volcano: KUCB article published online February 7, 2017, available at http://kucb.org/post/not-all-eruptions-are-equal-submarine-bogoslof-volcano
Ash cloud restricts Asia-US airfreight, 2017
Cheshire, L., 2017, Ash cloud restricts Asia-US airfreight: Asia Fruit article published online June 27, 2017, available at http://www.fruitnet.com/asiafruit/article/172636/volcanic-ash
2 Bogoslof eruptions send ash clouds miles above Aleutians, 2017
Hollander, Z., 2017, 2 Bogoslof eruptions send ash clouds miles above Aleutians: Alaska Dispatch News article published online June 27, 2017, available at https://www.adn.com/alaska-news/environment/2017/06/27/bogoslof-erupts-yet-again-with-more-to-come-soon/
New equipment helps scientists keep tabs on Bogoslof now and study it later, 2017
Sobel, Z., 2017, New equipment helps scientists keep tabs on Bogoslof now and study it later: Alaska Public Media article published online June 19, 2017, available at http://www.alaskapublic.org/2017/06/19/new-equipment-helps-scientists-keep-tabs-on-bogoslof-now-and-study-it-later/
Air freight shippers hit as volcanic ash plume hits transpacific capacity, 2017
Lennane, A., 2017, Air freight shippers hit as volcanic ash plume hits transpacific capacity: Loadstar article published online June 26, 2017, available at https://theloadstar.co.uk/air-freight-shippers-hit-volcanic-ash-plume-hits-transpacific-capacity/
Bogoslof Volcano in 'Unpredictable Condition' After Eruption Sends Ash 30,000 Feet into the Air, 2017
Glum. J., 2017, Bogoslof Volcano in 'Unpredictable Condition' After Eruption Sends Ash 30,000 Feet into the Air: Newsweek article published online July 10, 2017, available at http://www.newsweek.com/bogoslof-volcano-eruption-alaska-flights-634298.
Alaska’s tiny Bogoslof volcano erupts again, sending an ash cloud miles above the Aleutians, 2017
Hanlon, T., 2017, Alaska’s tiny Bogoslof volcano erupts again, sending an ash cloud miles above the Aleutians: Anchorage Daily News article published online August 7, 2017, available at https://www.adn.com/alaska-news/2017/08/07/alaskas-tiny-bogoslof-volcano-erupts-again-sending-an-ash-cloud-miles-above-the-aleutians/.
Volcanoes of the World, 2013
Global Volcanism Program, 2013, Volcanoes of the World, v. 4.5.3. Venzke, E (ed.): Smithsonian Institution. Downloaded 2017. http://dx.doi.org/10.5479/si.GVP.VOTW4-2013
Scientists Capture Sounds of Volcanic Thunder, 2018
Associated Press, 2018, Scientists Capture Sounds of Volcanic Thunder: American Geophysical Union press release published online March 13, 2018, available at https://news.agu.org/press-release/scientists-capture-sounds-of-volcanic-thunder/
Volcanic thunder from explosive eruptions at Bogoslof volcano, Alaska, 2018
Haney, M.M., Van Eaton, A.R., Lyon, J.J., Kramer, R.L., Fee, David, Iexxi, A.M., 2018, Volcanic thunder from explosive eruptions at Bogoslof volcano, Alaska: Geophysical Research Letters, v. 45, n. 8, doi: 10.1002/2017/GL076911.
Overview, chronology, and impacts of the 2016-2017 eruption of Bogoslof volcano, Alaska, 2019
Coombs, Michelle, Wallace, Kristi, Cameron, Cheryl, Lyons, John, Wech, Aaron, Angeli, Kim, and Cervelli, Peter, 2019, Overview, chronology, and impacts of the 2016-2017 eruption of Bogoslof volcano, Alaska: Bulletin of Volcanology, v, 81, n. 62, doi:10.1007/s00445-019-1322-9.
Comparison of short-term seismic precursors and explosion parameters during the 2016-2017 Bogoslof eruption, 2019
Tepp, Gabrielle, and Haney, Matthew, 2019, Comparison of short-term seismic precursors and explosion parameters during the 2016-2017 Bogoslof eruption: Bulletin of Volcanology, v. 81, n. 63, doi:10.1007/s00445-019-1323-8.
Using earthquakes, T waves, and infrasound to investigate the eruption of Bogoslof Volcano, Alaska, 2018
Wech, A., Tepp, G., Lyons, J., and Haney, M., 2018, Using earthquakes, T waves, and infrasound to investigate the eruption of Bogoslof volcano, Alaska: Geophysical Research Letters, v. 45, no. 14, p. 6918-6925.
Seismo-acoustic evidence for vent drying during shallow submarine eruptions at Bogoslof volcano, Alaska, 2020
Fee, David, Lyons, John, Haney, Matthew, Wech, Aaron, Waythomas, Christopher, Diefenbach, A.K., Lopez, Taryn, Van Eaton, Alexa, and Schneider, David, 2020, Seismo-acoustic evidence for vent drying during shallow submarine eruptions at Bogoslof volcano, Alaska: Bulletin of Volcanology, v. 82, n. 2, 14 p.,doi:10.1007/s00445-019-1326-5.
2016-17 evolution of the submarine-subaerial edifice of Bogoslof volcano, Alaska, based on analysis of satellite imagery, 2019
Waythomas, C.F., Angeli, K., Wessels, R., and Schneider, D, 2020, 2016-17 evolution of the submarine-subaerial edifice of Bogoslof volcano, Alaska, based on analysis of satellite imagery: Bulletin of Volcanology v. 82, doi:https://doi.org/10.1007/s00445-020-1363-0.
Petrology of the 2016-2017 eruption of Bogoslof Island, Alaska, 2019
Loewen, M.L., Izbekov, Pavel, Moshrefzadeh, Jamshid, Coombs, Michelle, Larsen, Jessica, Graham, Nathan, Harbin, Michelle, Waythomas, Christopher, and Wallace, Kristi, 2019, Petrology of the 2016-2017 eruption of Bogoslof Island, Alaska: Bulletin of Volcanology v. 81, n. 72, 20 p., doi:10.1007/s00445-019-1333-6.
Geology and eruptive history of Bogoslof volcano, 2020
Waythomas, C.F., Loewen, M., Wallace, K.L., Cameron, C.E., and Larsen, J.F., 2020, Geology and eruptive history of Bogoslof volcano: Bulletin of Volcanology, v. 82, doi: https://doi.org/10.1007/s00445-019-1352-3.
Infrasound generated by the 2016-2017 shallow submarine eruption of Bogoslof volcano, Alaska, 2020
Lyons, J.J., Iezzi, A.M., Fee, David, Schwaiger, H.F., Wech, A.G., and Haney, M.M., 2020, Infrasound generated by the 2016-2017 shallow submarine eruption of Bogoslof volcano, Alaska: Bulletin of Volcanology, n. 82, doi: https://doi.org/10.1007/s00445-019-1355-0.
Seismic character and progression of explosive activity during the 2016-2017 eruption of Bogoslof volcano, Alaska, 2020
Searcy, Cheryl, and Power, J.A., 2020, Seismic character and progression of explosive activity during the 2016-2017 eruption of Bogoslof volcano, Alaska: Bulletin of Volcanology, n. 82, doi: https://doi.org/10.1007/s00445-019-1343-4.
Constraints on eruption processes and event masses for the 2016-2017 eruption of Bogoslof volcano, Alaska, through evalution of IASI satellite SO2 masses and complementary datasets, 2020
Lopez, Taryn, Lieven, Clarisse, Schwaiger, Hans, Van Eaton, Alexa, Loewen, Matthew, Fee, David, Lyons, John, Wallace, Kristi, Searcy, Cheryl, Wech, Aaron, Haney, Matthew, Schnieder, David, and Graham, Nathan, 2020, Constraints on eruption processes and event masses for the 2016-2017 eruption of Bogoslof volcano, Alaska, through evalution of IASI satellite SO2 masses and complementary datasets: Bulletin of Volcanology, v. 82, doi: https://doi.org/10.1007/s00445-019-1348-z.
Did ice-charging generate volcanic lightning during the 2016-2017 eruption of Bogoslof volcano, Alaska?, 2020
Van Eaton, A.R., Schneider, D.J., Smith, C.A., Haney, M.M., Lyons, J.J., Said, Ryan, Fee, David, Holzworth, R.H., and Mastin, LG., 2020, Did ice-charging generate volcanic lightning during the 2016-2017 eruption of Bogoslof volcano, Alaska?: Bulletin of Volcanology, v, 82, doi: https://doi.org/10.1007/s00445-019-1350-5
Seismic and hydroacoustic observations of the 2016-17 Bogoslof eruption, 2020
Tepp, Gabrielle, Dziak, R.P., Haney, M.M., Lyons, J.J., Searcy, Cheryl, Matsumoto, Haru, and Haxel, Joseph, 2020, Seismic and hydroacoustic observations of the 2016-17 Bogoslof eruption: Bulletin of Volcanology, v. 82, doi: https://doi.org/10.1007/s00445-019-1344-3.
Characteristics of thunder and electromagnetic pulses from volcanic lightning at Bogoslof volcano, Alaska, 2020
Haney, M.M., Van Eaton, A.R., Lyons, J.J., Kramer, R.L., Fee, David, Iezzi, A.M., Dziak, R.P., Anderson, Jacob, Johnson, J.B., Lapierre, J.L., and Stock, Michael, 2020, Characteristics of thunder and electromagnetic pulses from volcanic lightning at Bogoslof volcano, Alaska: Bulletin of Volcanology v. 82, doi: https://doi.org/10.1007/s00445-019-1349-y.
Mechanisms for ballistic block ejection during the 2016-2017 shallow submarine eruption of Bogoslof volcano, Alaska, 2020
Waythomas, C.F., and Mastin, L.G., 2020, Mechanisms for ballistic block ejection during the 2016-2017 shallow submarine eruption of Bogoslof volcano, Alaska: Bulletin of Volcanology, v. 82, doi: https://doi.org/10.1007/s00445-019-1351-4.
Co-eruptive tremor from Bogoslof volcano: seismic wavefield composition at regional distances, 2020
Haney, M.M., Fee, David, McKee, K.F., Lyons, J.J., Matoza, R.S., Wech, A.G., Tepp, Gabrielle, Searcy, Cheryl, and Mikesell, T.D., 2020, Co-eruptive tremor from Bogoslof volcano: seismic wavefield composition at regional distances: Bulletin of Volcanology, v. 82, doi: https://doi.org/10.1007/s00445-019-1347-0.
Satellite observations of the 2016-2017 eruption of Bogoslof volcano: aviation and ash fallout hazard implications from a water-rich eruption, 2020
Schneider, D.J., Van Eaton, A.R., and Wallace, K.L., 2020, Satellite observations of the 2016-2017 eruption of Bogoslof volcano: aviation and ash fallout hazard implications from a water-rich eruption: Bulletin of Volcanology, v, 82, doi: https://doi.org/10.1007/s00445-020-1361-2.
2016 Volcanic activity in Alaska - Summary of events and response of the Alaska Volcano Observatory, 2020
Cameron, C.E., Dixon, J.P., Waythomas, C.F., Iezzi, A.M., Wallace, K.L., McGimsey, R.G., and Bull, K.F., 2020, 2016 Volcanic activity in Alaska-Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Scientific Investigations Report 2020-5125, 63 p., https://doi.org/10.3133/sir20205125.
Dating individual zones in phenocrysts from the 2016–2017 eruption of Bogoslof volcano provides constraints on timescales of magmatic processes, 2023
Moshrefzadeh, J., Izbekov, P., Loewen, M., Larsen, J., and Regan, S., 2023, Dating individual zones in phenocrysts from the 2016–2017 eruption of Bogoslof volcano provides constraints on timescales of magmatic processes: Journal of Volcanology and Geothermal Research v. 435, article no. 107741, 16 p. https://doi.org/10.1016/j.jvolgeores.2022.107741.
Infrasound single-channel noise reduction: application to detection and localization of explosive volcanism in Alaska using backprojection and array processing, 2023
Sanderson, R.W., Matoza, R.S., Fee, D., Haney, M.M., and Lyons, J.J., 2023, Infrasound single-channel noise reduction: application to detection and localization of explosive volcanism in Alaska using backprojection and array processing: Geophysical Journal International v. 232, no. 2, p. 1684-1712. https://doi.org/10.1093/gji/ggac182
Automatic identification and quantification of volcanic hotspots in Alaska using HotLINK: the hotspot learning and identification network, 2024
Saunders-Schultz, P., Lopez, T., Dietterich, H., and Girona, T., 2024, Automatic identification and quantification of volcanic hotspots in Alaska using HotLINK - the hotspot learning and identification network: Frontiers in Earth Science v. 12, 1345104. https://doi.org/10.3389/feart.2024.1345104
Full-text PDF 46.1 MB From field station to forecast: managing data at the Alaska Volcano Observatory, 2024
Coombs, M.L., Cameron, C.E., Dietterich, H.R., Boyce, E.S., Wech, A.G., Grapenthin, R., Wallace, K.L., Parker, T., Lopez, T., Crass, S., Fee, D., Haney, M.M., Ketner, D., Loewen, M.W., Lyons, J.J., Nakai, J.S., Power, J.A., Botnick, S., Brewster, I., Enders, M.L., Harmon, D., Kelly, P.J., and Randall, M., 2024, From field station to forecast: managing data at the Alaska Volcano Observatory: Bulletin of Volcanology v. 86, 79. https://doi.org/10.1007/s00445-024-01766-0