Report on Popocatepetl (Mexico) — September 2017
Bulletin of the Global Volcanism Network, vol. 42, no. 9 (September 2017)
Managing Editor: Edward Venzke. Report research and preparation by: Liz Crafford.
Popocatepetl (Mexico) Ongoing steam, gas, ash emissions, and lava dome growth and destruction, July 2016-July 2017
Please cite this report as:
Global Volcanism Program, 2017. Report on Popocatepetl (Mexico). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 42:9. Smithsonian Institution.
19.023°N, 98.622°W; summit elev. 5393 m
All times are local (unless otherwise noted)
Frequent historical eruptions have occurred since pre-Columbian time at México's Popocatépetl. More recently, activity picked up in the mid-1990s after about 50 years of quiescence. The current eruption, which has been ongoing since January 2005, has included frequent ash plumes rising generally 1-4 km above the 5.4-km-elevation summit, and numerous episodes of lava-dome growth and destruction within the 500-m-wide summit caldera. Multiple emissions of steam and gas occur daily, many contain small amounts of ash. Larger, more explosive events that generate ashfall in neighboring communities usually occur every month or two. Information about Popocatépetl comes from daily reports provided by México's Centro Nacional de Prevención de Desastres (CENAPRED). Many ash emissions are also reported by the Washington Volcanic Ash Advisory Center (VAAC). Satellite visible and thermal imagery and SO2 data also provide important observations. Activity through June 2016 was typical of the ongoing eruption with near-constant emissions of water vapor, gas, and ash, and at least two episodes of dome growth and destruction (BGVN 42:07). This report covers similar activity through July 2017.
Activity at Popocatépetl during July 2016-July 2017 was typical of the ongoing eruption since 2005. Near constant steam-and-gas emissions often contained minor amounts of ash. Explosions with ash plumes occurred several times a week during most months. Incandescence at the summit was usually visible on clear nights; nighttime explosions revealed incandescent blocks travelling 100 m or more down the flanks. Large ash explosions on 25 and 26 November 2016 sent ash plumes to 11.5 and 10.9 km altitude, respectively. Ashfall was reported from communities within about 35 km on five different occasions. Thermal activity slowly increased during 2016 to high levels indicative of dome growth during December 2016 and January 2017; they diminished early in 2017 and then fluctuated through July 2017. Sulfur dioxide plumes were persistent in satellite data with plume densities generally exceeding two Dobson Units (DU) several times each month.
Activity during July-September 2016. Intermittent activity continued during July 2016. Tens of daily emissions of gas and steam were reported during the first and last weeks of the month; explosions with ash plumes also generally occurred daily during those weeks, and incandescence was visible on clear nights. The Washington VAAC reported ash emissions observed on 3 July at 7.9 km altitude drifting W, 2.5 km above the summit. Explosions on 4 July produced ash plumes that rose to 8.5 km altitude, just over 3 km above the crater and drifted WSW. Ashfall was reported in Atlatlahucan (30 km WSW) and Tepetlixpa (20 km W). Continuous ash emissions rising to just under 6 km altitude were seen in satellite imagery on 10 July extending almost 40 km W from the summit. Multiple daily explosions occurred during 24-26 July (figure 84). A small cloud of volcanic ash was centered about 35 km W of the summit early on 25 July at 5.8 km altitude. Later in the day, another plume was observed at 7 km altitude drifting WNW and then WSW before dissipating. Satellite imagery confirmed an ash emission on 30 July that rose to 6.7 km altitude and drifted W-WSW. MODVOLC thermal alerts were issued on 3, 10 (2) and 27 July. Small SO2 plumes were recorded daily by the Aura instrument on the OMI satellite. Most measured around two Dobson Units (DU) with an area of about 100,000 km2.
|Figure 84. An ash plume at Popocatépetl drifts W from the summit on 25 July 2016 as captured by the ALTZOMONI CENAPRED webcam located about 10 km N of the volcano. Courtesy of CENAPRED.|
Tens of daily emissions were common during August 2016, some of which contained minor amounts of ash. Six landslides were detected by the seismic network on 11 August (figure 85). The two largest had volumes of 440 and 220 m3. The Washington VAAC reported an ash plume moving NW at 7.3 km altitude just after midnight on 1 August, extending about 35 km from the summit. A short while later, continuous emissions were reported extending up to 75 km W at 6.1 km altitude. By 0910 UTC, they extended 220 km WNW at 7.3 km altitude. The edge of the plume farthest from the summit had reached close to 500 km W by 1945 UTC when it was last observed. The webcam captured an emission on 11 August but it was not visible in satellite imagery due to weather clouds. An explosion on 12 August generated an ash plume that rose 2.5 km above the 5.4-km-high summit crater and drifted WNW, causing ashfall in Ozumba (18 km W) and Atlautla (16 km W). An explosion at 0034 on 13 August ejected incandescent material onto the flanks. An ash emission was seen in satellite imagery at 8.2 km altitude about 35 km W of the summit later in the morning. Another ash emission was observed with the webcam midday on 15 August that produced an ash plume that rose to 8.5 km altitude and drifted WSW. An ash plume on 21 August drifted W at 6.1 km altitude, and one on 28 August was observed in satellite imagery moving NNW below 7.3 km altitude. Two explosions on 27 August at 1505 and 1537, and one at 0559 on 28 August sent incandescent fragments down the flanks.
|Figure 85. A landslide on 11 August 2016 at Popocatépetl was captured by the Tlamacas CENAPRED Webcam located about 5 km N of the summit. Courtesy of CENAPRED.|
MODVOLC thermal alerts were issued on 1 (4), 3, 4, 11 (2), 13, and 29 August 2016. SO2 plumes were also captured daily by the Aura Instrument on the OMI satellite, with similar values to those recorded during July. During an overflight of Popocatépetl on 30 August 2016 CENAPRED scientists confirmed that explosions during 27-28 August had destroyed lava dome 69 (first identified on 1 August). The crater which had hosted the dome was 300 m in diameter and 30 m deep (figure 86).
Only one MODVOLC thermal alert was reported on 14 September 2016. SO2 emissions continued at similar levels to the previous months. Tens of daily steam-and-gas emissions were recorded and crater incandescence was visible on clear nights. An explosion on 8 September produced an ash plume that rose 1.5 km above the crater. On 11 September, an explosion generated a plume that rose 1 km, and an explosion that night ejected incandescent material onto the flanks. CENAPRED reported two volcanic ash emissions on 14 September that rose to 7.3 km. Weather clouds prevented satellite observations of the first, but the second one was observed extending 10 km W of the summit, and reached about 50 km before dissipating. Minor amounts of volcanic ash and steam on 23 September extended NW about 30 km from the summit at 5.5 km altitude. The Mexico City Meteorological Weather Office (MWO) reported volcanic ash at 7.3 km altitude on 29 September, but it was not observed in satellite imagery due to weather clouds.
Activity during October-December 2016. An increase in thermal activity was responsible for ten MODVOLC thermal alerts on 4, 7, 14, 16 (2), 20, 23, 27, 28, and 30 October 2016. Although near-constant steam-and-gas emissions continued, some with minor amounts of ash, there was only one observation of an ash plume from the Washington VAAC, on 28 October at 6.4 km altitude drifting SW. Sulfur dioxide emissions appeared to decrease in the Aura satellite data, although there were values measured over two DU at least four days of the month. Fewer ash emissions were reported during November 2016 as well, but ten MODVOLC thermal alerts were reported on 5, 14, 24, 25, 26 (2), 28, and 30 (3) November.
Ash emissions increased significantly during the last week of November. An ash plume at 5.5 km altitude was visible 55 km E of the summit on 24 November. A larger emission on 25 November was observed at 9.1 km altitude towering above the summit and drifting N (figure 87) with additional ash emissions at 7.3 km altitude drifting SE. Ashfall was reported from this event in areas downwind, including in the municipalities of Atlixco (25 km SE), Tochimilco (15 km SSE), and San Pedro Benito Juárez (12 km SE). Emissions were observed as high as 11.5 km altitude drifting NE later in the day; they continued drifting ENE at 7.9 km into the next day before dissipating 250 km from the summit. A new ash emission on 26 November rose to 10.9 km altitude. It was visible 300 km S of the summit while a second ash cloud was centered 150 km S at 5.2 km altitude. Later in the day, an ash emission was observed at 6.7 km drifting SW.
|Figure 87. An ash plume at Popocatépetl rises toward 9.1 km altitude on 25 November 2016 as viewed from CENAPRED'S Altzomoni WEBCAM, located about 10 km N of the summit. Courtesy of CENAPRED.|
During 28-29 November 2016 there was another pulse of activity with 48 detected emissions. Beginning at 0559 on 28 November, water vapor, gas, and ash emissions became constant, rising as high as 1.5 km above the crater rim and drifting NE. Incandescent fragments were ejected 300-800 m from the crater, mainly onto the NE flank during the next night (figure 88). Ash fell in Atlixco, Chiautzingo (25 km NE), Domingo Arenas (22 km NE), Huejotzingo (27 km NE), Juan C. Bonilla (33 km NE), San Andrés Calpan (18 km NE), and San Martín Texmelucan (Puebla state, 35 km NNE), and in San Miguel (Tlaxcala state). Plumes from these emissions were reported on 29 November at 7.3 km altitude, and they drifted as far as 170 km NE; remnant ash was observed over the Gulf of Mexico on 30 November. Emission intensity increased again on 30 November and a new continuous plume at 6.4 km altitude extended 370 km NE before dissipating. At 1500 UTC on 30 November, a second higher plume was reported by the Washington VAAC at 9.3 km altitude centered 400 km NE of the summit. The continuous emissions became intermittent on 1 December; the last of the emissions dissipated about 200 km NE of the summit. A short puff noted on the webcam late on 1 December was the last VAAC report for 2016.
|Figure 88. Incandescent fragments were ejected 300-800 m onto the NE flank of Popocatépetl on 29 November 2016, as seen from the Tlamacas webcam located about 5 km N of the volcano. Courtesy of CENAPRED.|
While ash emissions decreased during December 2016, steam-and-gas emissions continued, and thermal activity increased. MODVOLC alerts were reported 24 times on 17 different days. More substantial SO2 plumes than seen in previous months were also captured by the Aura satellite instrument on 8 and 31 December (figure 89). A new lava dome (71) first detected by CENAPRED on 29 and 30 November had almost completely filled the internal crater by 12 December (figure 90), reaching 280 m in diameter and 50 m thick. The volume of the dome was estimated to be about 3 million m3.
|Figure 90. A new lava dome was photographed at the summit of Popocatépetl during an overflight on 12 December 2016. Courtesy of CENAPRED.|
Activity during January-April 2017. Low-intensity steam-and-gas emissions continued during January 2017; incandescence was regularly observed at the summit. During January, only one emission was reported by the Washington VAAC, on 23 January at 7.6 km altitude drifting NW. They noted that the satellite imagery indicated the emission was mostly gas and water vapor with minor amounts of ash. Thermal activity continued to increase in January 2017 with 35 alerts reported on 26 days of the month. The increase in thermal activity was also visible in the MIROVA log radiative power information plotted from the MODIS thermal anomaly data (figure 91). SO2 plumes were also notable through 18 January, after which they decreased in both size and density in satellite data.
Ash emissions were reported on three days during February 2017. A plume on 7 February rose to 5.8 km altitude and drifted W, dissipating quickly. A plume on 12 February was reported at 6.1 km altitude drifting 10 km N of the summit. An ash emission was recorded on the CENAPRED webcam on 15 February (figure 92); it was seen in satellite imagery at 6.7 km altitude drifting NE, and dissipated after about six hours. Thermal activity decreased during February relative to January. MODVOLC only reported 16 thermal alerts on 11 days of the month.
|Figure 92. An ash emission from Popocatépetl on 15 February 2017 was later observed in satellite imagery at 6.7 km altitude drifting NE. Image taken by the Altzomoni webcam, located about 10 km N of the volcano. Courtesy of CENAPRED.|
Continued steam-and-gas emissions during March 2017 were accompanied by a few ash-bearing explosions. The webcam captured an ash emission on 8 March that the Washington VAAC observed in satellite imagery drifting N at 5.8 km altitude. Another emission late on 11 March rose to 6.1 km and drifted E; it contained mostly gas with only small amounts of ash. Late on 28 March, an ash cloud was observed in satellite imagery centered about 50 km ENE of the summit at 5.8 km altitude. Thermal activity continued to decrease with only ten MODVOLC thermal alerts issued on six different days during March.
Thermal alerts were fewer still during April 2017; one appeared on 6 April, and then a cluster of six were reported during 24-30 April. Ash emissions were reported by the Washington VAAC on 16, 20, 24, and 25 April. Constant emissions were seen by the webcam on 16 April; they likely contained ash, and were estimated to be at 6.1 km altitude. A small puff of ash was seen in satellite imagery on 20 April drifting S to about 35 km at the same altitude. Multiple emissions of ash mixed with steam and gas were observed in satellite imagery on 24 April moving SE at 5.6 km altitude. Constant steam-and-gas emissions continued throughout the month, with incandescence visible on clear nights. Tephra from explosions on 26 and 27 April was ejected 100 m NE of the crater.
Activity during May-July 2017. Thermal activity increased somewhat during May 2017. Seventeen MODVOLC alerts were reported on 13 different days. SO2 emissions with DU values greater than two occurred eight times during the month. Low intensity explosions with water vapor, gas, and ash emissions occurred daily throughout the month. On 18 May, the Washington VAAC reported an ash plume at 7.3 km altitude drifting N, and they observed a bright hotspot in shortwave imagery. Multiple emissions were later observed, with plumes rising to 7.6 km, moving NNE 70 km from the summit. A small puff of ash was seen in satellite imagery on 21 May at 7 km altitude approximately 25 km from the summit moving N. The leading edge of a new emission was observed the next day about 45 km SSW of the summit at 6.1 km altitude. An ash emission was observed on the CENAPRED webcam on 30 May, but weather clouds obscured any satellite observations.
MODVOLC thermal alerts were reported on 6, 16, 17, 18(3) and 21 June 2017. Observers noted material being ejected 200 m from the crater on 3 June. Cloud cover obscured satellite and webcam views of a reported ash plume on 12 June. A small ash emission was reported on 13 June 16 km W of the summit at 7.0 km altitude.
A series of ash emissions were reported by the Washington VAAC almost daily during 2-11 July 2017. A social media post by CENAPRED and a webcam image showed an ash emission (figure 93) on 2 July. It was observed by the Washington VAAC in satellite imagery moving SW at 6.7 km altitude. Minor ashfall on 2 July was also noted in Ozumba (18 km W), Amecameca (19 km NW), Tlalmanalco (26 km NW), Chalco (38 km NW), Ayapango (22 km NW), Tenango del Aire (28 km NW), and San Pedro Nexapa (14 km NW). An emission on 3 July was confirmed in visible satellite imagery drifting WNW at 6.7 km altitude. On 4 July, a plume was observed in satellite imagery 25 km NE of the summit at 7.6 km altitude. An ash emission observed in the webcam early on 6 July was not visible in satellite imagery due to weather clouds, but a larger emission that evening was spotted with difficulty at 7.6 km altitude, in spite of the weather clouds. CENAPRED reported that the plume was clearly visible nearly 2 km above the summit. The next day, clouds obscured the summit from the webcam, but an ash emission was clearly visible in satellite imagery at 7.6 km altitude moving NW. The webcam recorded additional emissions on 9 and 11 July; they were obscured from satellite images by weather clouds. A plume of mostly gas and steam with a small amount of ash near the summit extended 55 km W of the summit on 31 July at 6.4 km altitude.
|Figure 93. An ash emission at Popocatépetl on 2 July 2017 as seen from the Altzomoni webcam, 10 km N of the volcano. Courtesy of CENAPRED.|
MODVOLC thermal alerts were reported on 13-15, 21, 23 (2) and 28 July. Sulfur dioxide plumes with densities between one and two Dobson Units were captured by the Aura Instrument on the OMI satellite almost every day of the month.
Geologic Background. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time.
Information Contacts: Centro Nacional de Prevención de Desastres (CENAPRED), Av. Delfín Madrigal No.665. Coyoacan, México D.F. 04360, México (URL: http://www.cenapred.gob.mx/), Daily Report Archive (URL: https://www.gob.mx/cenapred/archivo/articulos?order=DESC&page=1); Washington Volcanic Ash Advisory Center (VAAC), Satellite Analysis Branch (SAB), NOAA/NESDIS OSPO, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ospo.noaa.gov/Products/atmosphere/vaac/, archive at: http://www.ssd.noaa.gov/VAAC/archive.html); 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/); 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/); NASA Goddard Space Flight Center (NASA/GSFC), Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/).