Logo link to homepage

Report on Pacaya (Guatemala) — November 2018

Bulletin of the Global Volcanism Network, vol. 43, no. 11 (November 2018)
Managing Editor: Edward Venzke. Report research and preparation by: Janine Krippner.

Pacaya (Guatemala) Frequent lava flows and Strombolian activity from April through September 2018

Please cite this report as:

Global Volcanism Program, 2018. Report on Pacaya (Guatemala). In: Krippner, J.B., and Venzke, E. (eds.), Bulletin of the Global Volcanism Network, 43:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN201811-342110.

Volcano Profile |  Complete Bulletin


Pacaya

Guatemala

14.382°N, 90.601°W; summit elev. 2569 m

All times are local (unless otherwise noted)


Pacaya is one of the most active volcanoes in Guatemala and is located 30 km south of the capital city. It has produced nearly continuous Strombolian eruptions, lava flows, and ash plumes for decades. The current activity is centered at the Mackenney cone and is largely directed towards the N due to the trough that developed during increased activity in 2010.

This report summarizes activity from April through September 2018, and is based on reports by Instituto Nacional de Sismología, Vulcanologia, Meteorología E Hidrologia (INSIVUMEH), Sistema de la Coordinadora Nacional para la Reducción de Desastres (CONRED), and satellite data. During this period, activity was dominated by gas plumes, Strombolian explosions, and numerous short lava flows that traveled mainly to the N to NW (see details below, table 6).

Activity remained constant through April (figure 94), with a significant increase at the end of the month. White and blue-white gas-and-steam plumes were frequently observed up to 800 m above the Mackenney crater with the dispersal depending on wind direction. There was a partial collapse of the cone within the Mackenney crater during the week of 7-13 April. Strombolian activity was constant, with explosions ejecting material up to 50 m above the crater, until 21 April when activity decreased due to a small collapse that occurred in the cone and temporarily sealed the conduit. After elevated seismicity that was the highest since 2014, activity increased again on 26 April when Strombolian explosions ejected material up to 150 m above the crater. On 28 April there were 25-50 explosions recorded per hour, reaching 200 m above the cone and generating shock waves observed by communities 4 km away. A lava flow reached 600 m in length, the longest lava flow since the 2010 eruption. This lava flow continued through to the end of the month. Throughout the month, between one and four lava flows were frequently active, with lengths varying from 50 to 500 m from the vent. Lava flows were distributed to the NW, W, SW, and S, and were sometimes accompanied by avalanches with blocks reaching 1 m in diameter.

Figure (see Caption) Figure 94. Typical activity at Pacaya in April 2018. Top left: Degassing at the Mackenney cone. Top right: lava flows moving S, SW, and W with incandescent avalanches from the lava flow fronts; photo by Jorge Mejicanos. Bottom left: Strombolian activity erupting incandescent material to 150 m above the crater prior to the formation of the lava flow; photo by William Chigna. Bottom right: Descent of lava flows accompanied by Strombolian activity; photo by Byron Castillo. Images courtesy of INSIVUMEH (April 2018 monthly report).

Two new lava flows were seen moving down the NW flank on 3 May (figure 95). Activity in the first few days of May also included white and bluish white gas-and-steam plumes rising up to 900 m above the crater and frequent Strombolian explosions ejecting material to a maximum of 100 m above the crater. Increased weak-to-moderate explosions on 4 May ejected material 50-80 m above the crater and fed the NW-flank lava flows (figures 96 and 97). A slight increase in activity was noted 15-16 May, when constant explosions ejected material up to 50-70 m above the crater that were occasionally heard out to 3 km away. On 20 May approximately 50 explosions per hour were recorded, with material reaching 50-100 m above the crater. Elevated activity on 16 May produced a lava flow towards the W. Lava flows were observed on 1-3, 6, 12, and 16 May, with recorded lengths reaching 200-600 m on the NE, NW, and W flanks.

Figure (see Caption) Figure 95. Two new lava flows were observed traveling down the NW flank of Pacaya on 3 May 2018. Top: A thermal image of the lava flows and the Strombolian activity at the crater visible at the top of the image. Bottom: the location of the lava flows (April 28 to May 4, 2018 Weekly Monitoring Report). Right: The active lava flows on 5 May. Courtesy of INSIVUMEH
Figure (see Caption) Figure 96. Two lava flows and the active crater of Pacaya on 4 May 2018. This figure also shows the location of Cerro Chino and the directions of La Corona and Centro de Visitantes. Courtesy of INSIVUMEH (April 2018 monthly report).
Figure (see Caption) Figure 97. Incandescent lava flows on Pacaya visible at night on 4 May 2018. The lava flows are approximately 500 m in length. Photo courtesy of CONRED (Bulletin 762018, 4 May).

White, blue-white, and gray-white plumes were frequently noted throughout June with heights above the crater ranging from 15 to 800 m. Strombolian activity continued, ejecting material up to maximum heights of 150 m, but more commonly 15-50 m above the crater. During 12-14 June ejecta reached 100-150 m above the crater, with explosions heard up to 10 km away on the 12th. An ash plume on the 13th reached 3.5 km above sea level and dispersed 10 km N and NW. A new lava flow was observed on 6-7 June accompanied by Strombolian explosions ejecting material up to 50 m above the crater (figure 98). No additional lava flows were reported this month.

Figure (see Caption) Figure 98. June 2018 activity of Pacaya. Top left: Lava flow on 6 June that was 50 m long by approximately 20 m wide; courtesy of CONRED (Bulletin no. 1112018). Top left: Lava flow on 7 June, photo by Pedro Morales, via CONRED. Bottom: Lava flow on 7 June, photo by Berner Villea via CONRED.

Throughout July activity consisted of gas-and-steam plumes, Strombolian activity, and lava flows. White and blue-white plumes were low earlier in the month, but reached 300-450 m above the crater from 25 July to the end of the month. Strombolian explosions continued, ejecting material up to 5 to 50 m above the crater. Lava flows were frequently produced through July, with lengths ranging from 40-500 m from the vent, towards the SE, N, NW, and W. A decrease in activity was recorded on 4 July, which then increased again on 7 July. This increase produced a lava flow down to 400 m on the N flank, with an average width of 40 m.

Similar activity continued through August. White and blue-white plumes rose 50-600 m above the crater throughout the month. Strombolian activity continued, with explosions ejecting material 10-30 m above the crater, often reported as reaching low levels throughout August. One to two active lava flows were frequently described in daily reports, with lengths ranging from 75 to 500 m and traveling towards the NE, N, NW, and W. A slight increase in Strombolian activity occurred on the 27 August, generating 3-5 explosions per hour with some explosions heard up to 10 km away.

Frequent lava flows continued through September, with one to four active flows noted in daily reports (figure 99). Lava flow lengths ranged from 150 to 300 m and moved towards the N, NW, and W. White and blue-white plumes were observed reaching up to 800 m above the crater. Strombolian activity continued, ejecting material up to 10-30 m above the crater.

Figure (see Caption) Figure 99. Lava flows on Pacaya in September 2018. Top: two new lava flows observed from San Vincente; photo by Wotzbely Suarez via CONRED. Bottom: A fumarole plume to a height of 300-400 m above the crater and a 200-m-long lava flow on the NW flank. Courtesy of INSIVUMEH.

Overall, Pacaya produced numerous short (up to 600 m long) lava flows from April through September 2018 (figure 100), along with frequent degassing and fumarolic plumes, and Strombolian activity. Lava emissions and Strombolian activity were centered at the active Mackenney cone and vents on the NW flank. There was a significant reduction in lava flow extrusion in June, evident by the lack of MODVOLC thermal alerts (figure 101) and the reduction in MIROVA thermal energy detected (figure 102). Activity then remained frequent from July through September.

Figure (see Caption) Figure 100. Examples of active vents and lava flows (bright yellow-orange) at Pacaya from July through October 2018. The lava flows are traveling towards the NE, N, and NW. These images demonstrate how the lava flows mostly originate on the flank due to weaknesses on the cone, it is rare that lava flows originate in the crater. False color (urban) images (bands 12, 11, 4) courtesy of Sentinel Hub Playground.
Figure (see Caption) Figure 101. There were 79 MODVOLC thermal alerts for Pacaya from April through September 2018, based around the active crater and lava flows on the flanks. Courtesy of HIGP – MODVOLC Thermal Alerts System.
Figure (see Caption) Figure 102. MIROVA thermal data showing detected energy for the period ending in October 2018. Activity was high from February through May, with a significant drop in activity in June and early July, then increased activity resumed in October. Courtesy of MIROVA.

Table 6. Summary of activity at Pacaya during April-September 2018. Information compiled from INSIVUMEH and CONRED reports.

Date Summary of Observations (all heights are above the crater unless specified)
01 Apr 2018 Moderate white/blue plume dispersed to the S. Strombolian explosions ejected material up to 5-25 m. Two lava flows to the W and NW to 200 m.
02 Apr 2018 White/blue plume towards the S. Strombolian explosions ejected material up to 35 m. A lava flow continues on the NW flank to 250 m.
04 Apr 2018 White/blue plume up to 50 m, towards the N. Strombolian explosions ejected material up to 5-15 m. Two lava flows towards the NW to 150 m, and SW to 150 m.
05 Apr 2018 Moderate white/blue plume dispersed to the S. Strombolian explosions ejected material up to 5-25 m. Two lava flows to the W and NW to 200 m.
06 Apr 2018 White/blue plume towards the S. Strombolian explosions ejected material up to 40 m. Two lava flows to the S and SW to 200 m.
08 Apr 2018 White/blue plume up to 250 m towards the S. Strombolian explosions ejected material up to 5-15 m. Three lava flows to the NW, W, and SW, to 250, 200, and 150 m.
09 Apr 2018 Moderate white/blue plume up to 50 m, towards the S. Strombolian explosions ejected material up to 5-25 m. Two lava flows to the NW and SW to 150 and 50 m.
07-13 Apr 2018 Partial collapse of the cone forming in the Mackenney crater.
10 Apr 2018 Fumarole plume towards the S. Weak Strombolian explosions ejected material to 40 m. One lava flow to the SW and S to 250 m.
11 Apr 2018 Moderate steam plume. Strombolian explosions ejected material up to 30 m. Two lava flows to the SW and S to 200 and 350 m, with accompanied avalanches.
13 Apr 2018 Two Lava flows to the S and SW to 250 and 200 m.
14 Apr 2018 White plume to 400 m, dispersed to the NE. Strombolian explosions continue. Two lava flows to the NW to 200 and 250 m.
15 Apr 2018 White/blue plume towards the SE. One lava flow to the NW to 250 m.
16 Apr 2018 White plume dispersed towards the S. Strombolian explosions continue. Two lava flows to the NW and W to 150 and 200 m.
17 Apr 2018 White/blue plume to the S. Two lava flows to the NW and SW to ~250 m. Strombolian explosions eject incandescent material up to 40 m.
18 Apr 2018 White plume up to 200 m, dispersed towards the N. Strombolian explosions continue. Four lava flows, two to the NW to 100 and 150 m, and two to the W to 50 and 150 m.
19 Apr 2018 Increased lava effusion in recent days. Since 18 April, four new lava flows on the SW, W, and NW flanks to 200-500 m, accompanied by constant avalanches. Strombolian explosions ejected material up to 40-50 m.
20 Apr 2018 Incandescence from lava flows observed at night.
21 Apr 2018 White plume up to 50 m, dispersed towards the S. Strombolian explosions continue. The four lava flows have ceased.
22 Apr 2018 Degassing plume up to 50 m, towards the N. Some Strombolian explosions.
23 Apr 2018 Some Strombolian explosions.
24 Apr 2018 White/blue plume up to 50 m. Some Strombolian explosions.
25 Apr 2018 White/blue plume up to 25 m, dispersed to the S. Strombolian explosions eject material up to 5-50 m.
26 Apr 2018 White/blue plume up to ~800 m. Strombolian explosions eject material up to 25-50 m.
27 Apr 2018 Low white/blue plume to the S. Strombolian explosions eject material up to 5-50 m.
28 Apr 2018 Lava flow 500 m to the NW. Two to four weak Strombolian explosions per day with incandescent material reaching 50 m.
29 Apr 2018 White/blue degassing to low altitude. Lava flow 500 m to the NW.
01 May 2018 Over the past few days a new eruptive phase began. White/blue plume up to 150-200 m. Strombolian explosions ejected material up to 20 m. One lava flow towards Cerro Chino to 200-300 m.
02 May 2018 White/blue plume from the NW flank. Lava flow 500 m to the NW.
03 May 2018 Moderate white/blue plume up to 150-200 m. Strombolian explosions ejected material up to 20 m. One lava flow towards Cerro Chino to ~500 m. Incandescence observed.
04 May 2018 Change in eruptive behavior, generating constant weak-moderate explosions ejecting material up to 50-80 m above the Mackenney cone.
06 May 2018 Weak-moderate white/blue plume up to 100 m. Strombolian explosions ejected material up to 15 m. One 600 m lava flow to the NE.
07 May 2018 Strombolian explosions continue.
09 May 2018 White/blue plume up to 300 m, dispersed to the S. Strombolian explosions ejected material up to 50 m. Incandescence observed.
10 May 2018 Moderate white/blue plume up to 700 m. Strombolian explosions ejected material up to 25-100 m.
11 May 2018 White/blue plume up to 600 m. Strombolian explosions ejected material up to 15-50 m.
12 May 2018 Strombolian explosions sent material up to 50-75 m. Lava flow to the W.
13 May 2018 White/blue plume up to ~200 m, dispersed to the SW. Strombolian explosions eject material up to 25 m. Incandescence observed.
14 May 2018 Moderate white/blue plume to ~800 m, dispersed to the W. Strombolian explosions ejected material to 7-50 m.
15 May 2018 White plume to 600-700 m, dispersed towards the W. Strombolian explosions ejected material up to 10-50 m.
16 May 2018 Constant Strombolian explosions ejected material up to 50-70 m, explosions occasionally heard 3 km away. Activity increased and produced a lava flow on the W flank.
17 May 2018 White/blue plume up to 300-400 m, dispersed to the S. Strombolian explosions ejected material up to 25 m. Incandescence observed.
18 May 2018 White/blue plume up to 400 m, dispersed to the W. Strombolian explosions ejected material up to 5-15 m.
19 May 2018 White/blue plume up to 200 m, dispersed to the N. Strombolian explosions ejected material up to 10-50 m.
20 May 2018 Strombolian explosions at Mackenney crater ejected material up to 50 m. Small avalanches on W flank.
21 May 2018 White/blue degassing plume up to 100 m, dispersed towards the S. Strombolian explosions ejected material up to 25 m. Incandescence observed in the evening.
22 May 2018 Moderate white/blue degassing plume up to 900 m, dispersed towards the S. Strombolian explosions ejected material up to 5-10 m.
23 May 2018 White plume up to ~50 m, dispersed towards the S. Strombolian explosions ejected material up to 25 m. Incandescence observed.
24 May 2018 Moderate white/blue plume up to 500-600 m, dispersed towards the W. Strombolian explosions ejected material up to 5-10 m. Incandescence observed.
25 May 2018 White/blue plume up to 300 m, dispersed towards the N. Strombolian explosions ejected material up to 25 m. Incandescence observed.
26 May 2018 White plume up to 800 m, dispersed towards the E. Strombolian explosions ejected material up to 10-50 m.
28 May 2018 White/blue degassing plume up to 50 m, dispersed towards the S. Strombolian explosions ejected material up to 50-100 m. Incandescence observed.
29 May 2018 White/blue degassing plume up to 200 m, dispersed towards the S. Strombolian explosions ejected material up to 50-100 m, with ~50 explosions per hour. Incandescence observed.
31 May 2018 White/blue degassing plume up to 250 m, dispersed towards the S.
01 Jun 2018 White plume up to 500 m towards the N and NE. Strombolian explosions ejected material up to 15-50 m.
02 Jun 2018 White plume up to 200 m, dispersed towards the W. Strombolian explosions ejected material up to 15-50 m.
03 Jun 2018 White plume towards the W. Strombolian explosions ejected material up to 25-50 m.
05 Jun 2018 White/blue plume up to 400-600 m towards the W. Occasional weak explosions.
06 Jun 2018 New lava flow 50 m long by 20 m wide. Strombolian explosions eject material up to 50 m. White plume up to 200 m.
07 Jun 2018 White plume to up 200-300 m towards the N. The lava flow continues.
08 Jun 2018 Low white/blue plume towards the W. Strombolian explosions ejected material up to 15-50 m.
09 Jun 2018 White/blue degassing plume up to 400 m, dispersed towards the W.
10 Jun 2018 White/blue plume up to 300-400 m towards the SW. Strombolian explosions ejected material up to 15-50 m.
11 Jun 2018 White plume towards the W. Strombolian explosions increased and ejected material up to 20-40 m.
12 June 2018 Strombolian explosions eject material up to 150 m, generating sounds heard ~10 km away.
13 June 2018 White/blue degassing plume up to 150-300 m, dispersed towards the N. Strombolian explosions eject material up to 15-100 m. Ash plume up to 3.5 km above sea level, dispersed to the N and NE to 10 km.
14 Jun 2018 Gray/white plume up to 600-800 m, dispersed to the NE. Strombolian explosions eject material up to 15-100 m.
16 Jun 2018 Abundant white/blue plume up to 50 m, dispersed to the N and NW. Increased Strombolian explosions eject material up to 25-40 m.
17 Jun 2018 Some Strombolian explosions at the Mackenney crater.
18 Jun 2018 Abundant white/blue plumes up to 25 m towards the W. Increased Strombolian explosions ejected material up to 25-50 m.
19 Jun 2018 White plume up to 15 m towards the N. Strombolian explosions ejected material up to 5-25 m above the Mackenney crater.
20 Jun 2018 White/blue degassing plume up to 25 m, dispersed towards the N. Strombolian explosions ejected material up to 5-30 m.
21 Jun 2018 Moderate white/blue degassing plume up to 15 m, dispersed towards the N. Strombolian explosions ejected material up to 5-25 m.
22 Jun 2018 White/blue plume up to 25 m towards the S. Strombolian explosions ejected material up to 25-50 m.
23 Jun 2018 White/blue degassing plume up to 150 m, dispersed towards the W. Strombolian explosions ejected material up to 15, 50, and 70 m.
24 Jun 2018 Low white/blue degassing plume, dispersed towards the W. Strombolian explosions ejected material up to 25 m.
25 Jun 2018 Degassing plume from Mackenney crater up to 30 m towards the W. Small Strombolian explosions occurred.
26 Jun 2018 Strombolian explosions ejected material up to 15-30 m.
27 Jun 2018 Low white/blue degassing plume, dispersed towards the S. Strombolian explosions ejected material up to 5-25 m.
28 Jun 2018 Low white/blue degassing plume, dispersed towards the S. Strombolian explosions ejected material up to 5-25 m.
29 Jun 2018 White/blue plume up to 50 m. Strombolian explosions ejected material up to 25 m.
30 Jun 2018 Low white/blue degassing plume, dispersed towards the S. Strombolian explosions ejected material up to 15-25 m.
01 Jul 2018 White/blue plume up to 200 m towards the SW. Strombolian explosions ejected material up to 15-50 m.
02 Jul 2018 Low white/blue plume, dispersed towards the S. Strombolian explosions ejected material up to 15-25 m.
03 Jul 2018 Low white/blue plume, dispersed towards the S. Strombolian explosions ejected material up to 5-30 m. Increase in activity generated two lava flows, one 5 x 40 m flow towards the N, one 30 x 50 m towards the SE.
04 Jul 2018 Activity and lava flows decreasing.
05 Jul 2018 Strombolian explosions eject material up to 25 m. A lava flow 60 x 400 m continues.
06 Jul 2018 Strombolian explosions eject material up to 5-25 m.
07 Jul 2018 Lava flow from the Mackenney crater, 400 m long with an average width of 30 m, moving towards the N.
08 Jul 2018 Lava flow continues, now 500 m long. Strombolian explosions ejected material up to 30 m. Degassing plume to 30 m towards the SW.
09 Jul 2018 Strombolian explosions ejected material up to 5-25 m. Incandescence observed.
10 Jul 2018 Strombolian explosions ejected material up to 5-25 m. Incandescence observed. Lava flow continues towards the N.
11 Jul 2018 Strombolian explosions ejected material up to 25-50 m. Incandescence observed. Lava flow continues towards the N to ~350 m.
12 Jul 2018 Small Strombolian explosions continue. Lava flow continues towards the N to ~100 m.
13 Jul 2018 Small white plume dispersed to the S. Strombolian explosions ejected material up to 5-25 m. A Lava flow continues towards the N to 200 m.
14 Jul 2018 Incandescence observed. Strombolian explosions ejected material up to 15-40 m. A ~150 m lava flow moved towards the N.
15 Jul 2018 Lava flow on the N to NW flank down to ~400 m, accompanied by small avalanches. Strombolian explosions ejected material up to 15-75 m.
16 Jul 2018 Strombolian explosions ejected material up to 5-25 m. Incandescence observed. A lava flow descended towards the NW to ~400 m.
17 Jul 2018 Incandescence observed. Strombolian explosions eject material up to 25-50 m. A new lava flow moved towards the N.
18 Jul 2018 Degassing and Strombolian explosions produced material up to 25-30 m. A 500 m lava flow continued towards the N.
19 Jul 2018 Strombolian explosions ejected material to a low level. A 300 m lava flow descended towards the N.
20 Jul 2018 Low white/blue plume towards the S. Incandescence observed during the night/morning. Strombolian explosions ejected material up to 5-25 m. A 200 m lava flow moving towards Cerro Chino.
21 Jul 2018 White/blue plume displaced towards the W. Lava flow continues 300 m towards the N.
22 Jul 2018 White/blue plume dispersed towards the S. Strombolian explosions ejected material to a low level. A lava flow moved towards the NW to ~500 m.
23 Jul 2018 Strombolian explosions ejected material to a low level. A lava flow moved towards the NW to ~250 m.
24 Jul 2018 Low white/blue plume towards the S. Strombolian explosions ejected material up to 10-30 m. Lava flow to ~200 m towards Cerro Chino.
25 Jul 2018 White/blue plume up to 450 m, dispersed towards the S. Strombolian explosions ejected material to a low level. A 75 x 250 m lava flow moved towards the NW.
26 Jul 2018 White/blue plume up to 300 m, dispersed towards the W. Strombolian explosions ejected material to a low level. A lava flow moved towards the NW to 200 m.
27 Jul 2018 White plume up to 300 m, dispersed towards the W. Strombolian explosions ejected material to a low level. A lava flow moved towards the NW to 200 m.
28 Jul 2018 Moderate white/blue degassing plume dispersed towards the S. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 150 m.
29 Jul 2018 White plume up to 300 m, dispersed towards the S. Strombolian explosions ejected material to a low level. Two lava flows moved towards the W to 50 and 150 m.
30 Jul 2018 Moderate white/blue degassing plume dispersed towards the S. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 200 m.
31 Jul 2018 White plume up to 200 m, dispersed towards the S. Strombolian explosions ejected material to a low level. A lava flow moved 150 m towards the NW.
01 Aug 2018 White/blue plume up to 600 m, dispersed towards the W. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 500 m.
02 Aug 2018 White/blue plume dispersed towards the N. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 300 m.
03 Aug 2018 White/blue plume up to 50 m, dispersed towards the SW. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 150 m.
04 Aug 2018 White plume dispersed towards the SE. Strombolian explosions ejected material up to 30 m. A lava flow moved towards the N to 300 m.
05 Aug 2018 Moderate white plume up to 100 m, dispersed towards the S. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 300 m.
06 Aug 2018 White plume dispersed towards the SE. Strombolian explosions ejected material up to 30 m. Lava flow continues 300 m towards the N.
07 Aug 2018 Low white/blue plume dispersed towards the S. Strombolian explosions ejected material up to 10-50 m. Two lava flows to the NE to 200 and 400 m.
08 Aug 2018 Moderate white plume dispersed towards the S. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 150 m.
09 Aug 2018 Moderate white/blue plume up to 250 m, dispersed towards the W. Strombolian explosions ejected material to a low level. A lava flow moved towards the W to 150 m.
10 Aug 2018 Moderate white/blue plume dispersed towards the S. Strombolian explosions ejected material to a low level. Two lava flows moved towards Cerro Chino to 75 and 300 m.
11 Aug 2018 Low white/blue plume, dispersed towards the S. Strombolian explosions ejected material up to 10-25 m. A lava flow moved towards Cerro Chino to 250 m.
12 Aug 2018 Moderate white/blue plume up to 500 m, dispersed towards the NW. Strombolian explosions ejected material to a low level. A lava flow moved towards Cerro Chino to 300 m.
13 Aug 2018 Small Strombolian explosions. Weak white/blue plume up to ~100 m. Lava flow ~300 m towards Cerro Chino.
14 Aug 2018 Strombolian explosions ejected material up to 25-30 m. Lava flow on the NW flank continues down to 300 m.
15 Aug 2018 Moderate white plume up to ~100 m, dispersed to the S. Strombolian explosions ejected material up to 5-20 m. Two lava flows moved towards Cerro Chino to 75 and 300 m.
16 Aug 2018 Low white/blue plume dispersed towards the S. Strombolian explosions ejected material low above the crater. 200 m lava flow on the N flank.
17 Aug 2018 Moderate white plume reached ~50 m and dispersed to the S. Two lava flows traveled towards Cerro Chino to ~75 to 300 m.
18 Aug 2018 Faint white/blue plume up to 300-400 m and dispersed to the SW. Strombolian explosions ejected material to a low height. One lava flow to the N to ~300 m.
19 Aug 2018 Moderate white/blue plume up to ~100 and 150 m and dispersed to the NW. Two lava flows active on the NW flank towards Cerro Chino to ~75 and 300 m.
20 Aug 2018 White plume up to 600 m, dispersed to the SW. Strombolian explosions ejected material up to 5-25 m. One lava flow to the N to ~300 m.
21 Aug 2018 White plume up to 600 m, dispersed to the W. One lava flow continues towards the N to ~300 m.
22 Aug 2018 Strombolian explosions ejected material to 25-30 m. The lava flow continues to 400 m on the N flank.
23 Aug 2018 White/blue moderate plume towards the S. Two lava flows traveled towards Cerro Chino to the NW.
24 Aug 2018 Strombolian explosions ejected material to a low height. Two lava flows traveled towards Cerro Chino to 200 and 300 m.
25 Aug 2018 Abundant degassing and explosions ejected material up to 30 m and deposited in the same crater. One 400 m lava flow on the N flank.
26 Aug 2018 Low white plume dispersing towards the S. Strombolian explosions ejected material to 5-30 m. One lava flow 350 m to the N.
27 Aug 2018 Slight increase of explosive activity, generating 3-5 explosions per hour.
31 Aug 2018 Degassing plume up to ~200 m, dispersed to the S. Strombolian explosions ejected material to a little above the crater. A lava flow moved towards the N to NW.
01 Sep 2018 White plume up to 800 m, dispersed towards the W. Strombolian explosions continue. A lava flow moved towards the N to 200 m.
02 Sep 2018 A 200-300 m lava flow was observed.
03 Sep 2018 Moderate white/blue plume up to 600 m, dispersed towards the NW. Incandescence was observed. A lava flow moved towards the NW to 200 m.
04 Sep 2018 White/blue plume up to 100 m, dispersed towards the W. Incandescence was observed. Two lava flows moved towards Cerro Chino.
05 Sep 2018 White/blue plume up to 800 m, dispersed towards the SW. Incandescence was observed. Two lava flows moved towards the NW to 100-200 m.
06 Sep 2018 Moderate white/blue plume dispersed towards the SW. Incandescence observed. Two lava flows moved towards the NW to 100-200 m.
07 Sep 2018 Moderate white/blue plume up to 50 m, dispersed towards the S. Incandescence observed. Two lava flows moved towards the NW to 200 m.
08 Sep 2018 Two lava flows observed from San Vicente.
09 Sep 2018 White/blue plume up to ~600 m towards the SW. Three lava flows 50, 150 and 300 m long.
10 Sep 2018 White/blue plume up to ~100 m, towards the N. Lava flow 300 m towards the NW.
11 Sep 2018 White/blue plume up to ~600 m, towards the N. Two lava flows ~150 and 200 m long towards Cerro Chino.
12 Sep 2018 White/blue plume up to ~300 m towards the S. Lava flow ~300 m towards Cerro Chino. Strombolian explosions ejected material up to 10-40 m.
13 Sep 2018 White/blue plume up to 50 m towards the N. During night/early morning incandescence was observed. Lava flow 200-300 m towards the NW-W.
14 Sep 2018 Strombolian explosions ejected material up to 5-25 m. Three lava flows to 150, 250, and 300 m towards Cerro Chino.
15 Sep 2018 Fumarole gases up to 500 m due to low winds. Three lava flows to 150, 250, and 300 m on the W flank. Strombolian explosions ejected material to 25 m.
16 Sep 2018 Fumarole degassing up to 300-400 m. Lava flow in the direction of Cerro Chino, 200 m in length.
17 Sep 2018 White/blue fumarole plume towards the S. Incandescence observed at night. Lava flow to 200 m towards the NW.
18 Sep 2018 Moderate blue/white degassing plume to low altitude. Strombolian explosions ejected material up to 5-25 m. Lava flow 200 m towards Cerro Chino.
19 Sep 2018 Moderate white/blue plume up to 50 m, dispersed towards the SW. Strombolian explosions ejected material up to 10-25 m. A lava flow moved towards the W.
20 Sep 2018 Degassing plume up to 500-600 m towards the W. Two lava flows towards Cerro Chino on NW flank down to 150 and 300 m. Strombolian explosions ejected material up to 15-30 m.
21 Sep 2018 Incandescence observed at the crater at night/early morning. Four lava flows down to 40, 150, and 200 m to the NW.
22 Sep 2018 Strombolian explosions ejected material up to 25-25 m. A lava flow moved towards Cerro Chino.
23 Sep 2018 Strombolian explosions ejected material up to 25-30 m. A lava flow moved towards Cerro Chino to 250-300 m.
24 Sep 2018 White/blue plume up to 100 m, dispersed towards the S. Two lava flows moved towards Cerro Chino to 75 and 150 m.
25 Sep 2018 Strombolian explosions ejected material up to 5-25 m. A lava flow moved 100-200 m to the NW.
26 Sep 2018 White plume dispersed towards the S. Incandescence observed. A lava flow moved towards Cerro Chino.
27 Sep 2018 Strombolian explosions ejected material up to 20 m. Two lava flows moved towards Cerro Chino to 250 and 300 m.
28 Sep 2018 A lava flow continued towards Cerro Chino. Incandescence was observed.
28 Sep 2018 Incandescence was observed. Strombolian activity continued. A lava flow moved towards Cerro Chino.

Geologic Background. Eruptions from Pacaya, one of Guatemala's most active volcanoes, are frequently visible from Guatemala City, the nation's capital. This complex basaltic volcano was constructed just outside the southern topographic rim of the 14 x 16 km Pleistocene Amatitlán caldera. A cluster of dacitic lava domes occupies the southern caldera floor. The post-caldera Pacaya massif includes the ancestral Pacaya Viejo and Cerro Grande stratovolcanoes and the currently active Mackenney stratovolcano. Collapse of Pacaya Viejo between 600 and 1500 years ago produced a debris-avalanche deposit that extends 25 km onto the Pacific coastal plain and left an arcuate somma rim inside which the modern Pacaya volcano (Mackenney cone) grew. A subsidiary crater, Cerro Chino, was constructed on the NW somma rim and was last active in the 19th century. During the past several decades, activity has consisted of frequent strombolian eruptions with intermittent lava flow extrusion that has partially filled in the caldera moat and armored the flanks of Mackenney cone, punctuated by occasional larger explosive eruptions that partially destroy the summit of the growing young stratovolcano.

Information Contacts: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hydrologia (INSIVUMEH), Unit of Volcanology, Geologic Department of Investigation and Services, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala (URL: http://www.insivumeh.gob.gt/); Coordinadora Nacional para la Reducción de Desastres (CONRED), Av. Hincapié 21-72, Zona 13, Guatemala City, Guatemala (URL: http://conred.gob.gt/www/index.php); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/).