Cleveland reported activity

Event Name : Cleveland 2017/2

Start:	February 3, 2017	Observed
Stop:	January 20, 2019 ± 14 Days	Observed

Lava dome:

Description: AVO raised the Aviation Color Code and Volcanic Alert Level at Cleveland on February 3, 2017, following satellite observations of a new lava dome growing within the summit crater. On Feburary 3, the lava dome was approximately 70 m (230 ft) in diameter.

On March 8, 2017, citing no new growth of the lava dome, AVO lowered the Aviation Color Code and Volcanic Alert Level at Cleveland back to YELLOW/ ADVISORY.

A small explosion was detected at Cleveland at 08:15 AKST, March 24, 2017 in both seismic and infrasound data. As a result, AVO increased the Aviation Color Code and Volcanic Alert Level to ORANGE/WATCH. The event was short-lived. Cloud cover obscured satellite views of the volcano. Following this explosion, no further volcanic activity was detected, and AVO lowered the levels to YELLOW/ADVISORY on April 4, 2017.

A new lava dome began growing in the summit crater in April, 2017. Slightly elevated surface temperatures were observed in satellite data, and the first visual indications of a new dome were recorded on April 15 with the presence of a less than 10-m-diameter lava dome. By April 23, the dome has grown to 45 m in diameter. Dome growth occurred with no obvious detectable seismicity. On April 24, AVO raised the Aviation Color Code and Volcanic Alert Level to ORANGE/WATCH.

Another explosion occurred at Cleveland at 7:17 pm May 16, 2017 AKDT (03:17 UTC May 17) and was initially detected by seismic and infrasound sensors. On June 7, satellite data showed lava effusion in the summit crater.

On June 26, 2017, citing declining unrest and no further signs of explosive activity, AVO lowered the color code and alert level at Cleveland from ORANGE/WATCH to YELLOW/ADVISORY.

On July 4, 2017, a moderate, 10-minute long eruption occurred at Cleveland and AVO raised the color code and alert level to ORANGE/WATCH. The explosion was detected by seismic and infrasound. In mid-July, a new lava dome appeared within the summit crater. This dome grew throughout July, and slowed or stopped growing in early August 2017. On August 22, 2017, a moderate, 1-minute long explosion occurred at Cleveland. It was detected by seismic and infrasound sensors and destroyed the new lava dome. Elevated surface temperatures were observed in satellite data prior to the explosion.

In early September, satellite data suggested another lava dome had begun forming. Another explosion occurred at Cleveland at 17:47 September 25 AKDT (01:47 September 26 UTC). The explosion lasted three minutes; a signal seen in satellite data 30 minutes after the eruption suggested a volcanic cloud, likely containing ash, south of the volcano and estimated at less than 15,000 ft asl. Satellite data from September 30 suggested another lava dome forming in the summit crater. This dome grew through most of October. A small, 30-second-long eruption occurred at Cleveland Volcano beginning at 10:45 October 28 AKDT (18:45 September 26 UTC). The explosion was detected by seismic and infrasound (air pressure) sensors. A very small explosion, detected seismically, occurred October 30 at 3:20 AM AKDT (11:20 UTC). Conditions were cloudy at the time with cloud tops at about 8,000 ft AMSL. No volcanic clouds associated with this explosion were observed in satellite views reaching above cloud level. These explosions partially destroyed the summit lava dome.

Two small explosions were detected in seismic and infrasound data on November 14 and 16. These recent events are less energetic than those seen previously, and no volcanic cloud was observed following either explosion. A number of small earthquakes were observed in seismic data on November 14. Satellite observations of the summit indicate that a lava dome remains in the crater, with recent explosions sourced from a vent in the middle of the dome.

On December 12, 2017, citing cessation of lava effusion, AVO lowered the aviation color code and alert level at Cleveland to YELLOW/ADVISORY. However, an explosion occurred at 4:20 am December 13, prompting AVO to again raise the color code and alert level to ORANGE/WATCH. The explosion produced an eruption cloud that was observed in satellite data to an altitude of up to 20,000 ft asl and moving to the east. AVO is raising the color code for Cleveland to Aviation Color Code ORANGE and Alert Level WATCH. A small explosion was detected in seismic and infrasound data at Cleveland volcano on Sunday, December 17, but was too small to generate an eruption plume that reached above the cloud layer present at the time.

A new lava flow was emplaced in the summit crater in early January 2018.

AVO again lowered Cleveland to YELLOW/WATCH on February 9, 2018.

A small explosion was detected in seismic and infrasound data on February 22, 2018. No ash cloud was detected from this event, yet several hours after the explosion (14:15 UTC 22 Feb), satellite data show moderately elevated surface temperatures extending about 2 km ESE from the summit, indicative of a warm deposit.

Local seismic and infrasound sensors recorded a small explosion on March 2, 2018. A volcanic cloud was observed heading ENE at an altitude of about 15,000 ft, and AVO raised the color code and alert level to ORANGE/WATCH. AVO lowered the color code and alert level to YELLOW/ADVISORY on March 5, 2018.

A small explosion occurred at 6:19 UTC March 15 (10:19 pm AKDT March 14), producing seismicity and atmospheric pressure waves that were measured on the seismic and infrasound stations at the volcano. No ash cloud was observed in cloudy satellite images acquired after the explosion.

Local seismic and infrasound sensors recorded a small explosion on April 4, 2018, and AVO raised the color code and alert level to ORANGE/WATCH. Satellite imagery acquired shortly after the eruption indicated hot material ejected during the explosion was deposited on the western flank of the volcano, possibly extending as far as the coastline. Subsequent satellite images showed a small ash cloud moving to the southwest of the summit at or below 15,000' above sea level. Hours later, a small, short-duration seismic event was accompanied by a signal in satellite data suggesting a small ash emission. On April 6, 2018, AVO lowered the color code and alert level to YELLOW/ADVISORY.

A small explosion at Cleveland volcano was detected on local seismic and infrasound stations on April 13 at 7:59 AKDT (15:59 UTC). No volcanic clouds were observed in satellite data from this minor explosive event.

Local seismic and infrasound sensors recorded a small explosion on May 4, 2018 (May 5 UTC) and AVO raised the color code and alert level to ORANGE/WATCH. Satellite data show that the recent explosion of Cleveland volcano at 05:49 UTC (21:49 local time) produced a small ash cloud up to 22,000 ft asl moving southeast. AVO again lowered the color code to YELLOW/ADVISORY on May 6, 2018.

Satellite observations of Cleveland Volcano on June 25, 2018 indicated the presence of a small circular lava flow, about 80 meters in diameter, covering the floor of the summit crater. In response, AVO raised the color code and alert level to ORANGE/WATCH.

Citing no explosive activity in late July, AVO lowered the aviation color code and volcanic alert level to YELLOW/ADVISORY no August 22, 2018.

Satellite data from early September again showed an emplaced lava dome in the crater, but it was not clear if the dome was actively growing.

Local seismic sensors recorded a small explosion on December 12, 2018, and AVO elevated Cleveland to ORANGE/WATCH. Another explosion occurred Wednesday, December 12, at 11:53 AM AKST (20:53 UTC). No ash cloud was observed after either event, though satellite views were largely obscured by clouds at the time. A short-lived explosion occurred on Saturday, December 16 at 7:37 AM AKST (16:37 UTC). A small ash cloud was observed in satellite views traveling to the northeast. Elevated surface temperatures were observed following this explosion. Local seismic sensors recorded a short-lived explosion at 3:17 UTC December 29 (18:17 AKST December 28). A pilot reported an ash cloud to 17,000 ft (5180 m) asl. Satellite images through January 2, 2019 show that the explosion enlarged the diameter of the summit crater by about 25 m (82 ft) and large ballistic blocks impacted the upper edifice north and east of the crater. AVO lowered the color code and alert level on January 7, 2019. On January 9, 2019 at 19:15 UTC (10:15 AKST January 9, 2019), the single local seismic sensor recorded a small, short-lived explosion. The explosion was not detected on regional AVO infrasound arrays, nor was a volcanic cloud observed above the meteorological clouds at 10,000 ft AMSL.

Beginning around January 12, 2019, satellite data showed a growing lava dome within Cleveland's summit crater. AVO raised Cleveland to ORANGE/WATCH on January 17, 2019. The lava dome grew for a couple weeks and began to subside. With no evidence of further eruptive activity, AVO lowered the color code and alert level to YELLOW/ADVISORY on February 25, 2019.