Nevados de Chillán

Photo of this volcano
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 36.863°S
  • 71.377°W

  • 3212 m
    10535 ft

  • 357070
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Weekly Report: 6 December-12 December 2017 Citation IconCite this Report


POVI reported that observations of Nevados de Chillán's Volcán Arrau dome complex during 7-11 December indicated phreatic explosions, ash emissions, and a new sulfur deposit on the flank. On 11 December Servicio Nacional de Geología and Minería (SERNAGEOMIN) reported that explosive activity generated an ash plume to 3 km above the complex. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Sources: Proyecto Observación Villarrica Internet (POVI), Servicio Nacional de Geología y Minería (SERNAGEOMIN)


Most Recent Bulletin Report: October 2017 (BGVN 42:10) Citation IconCite this Report


Intermittent ash emissions from new craters along the E flanks of Volcáns Nuevo and Arrau persist through September 2017

Nevados de Chillán, in the Chilean Central Andes, is a complex of late-Pleistocene to Holocene stratovolcanoes constructed along a NNW-SSE trend (figure 5). The Nuevo and Arrau craters, active during 1906-1945 and 1973-1986, respectively, are adjacent vents on the NW cone of a large stratovolcano complex 5 km SE of Cerro Blanco; the summit 1 km SE of Arrau is named Volcán Viejo (figure 6). A short eruption during August-September 2003 created a new fissure vent between the Nuevo and Arrau craters (BGVN 29:03, figure 3). Increased seismicity and fumarolic activity were recorded during December 2015, and a new eruption started with a phreatic explosion and ash emission on 8 January 2016 from a new crater on the E flank of Nuevo cones (BGVN 41:06). This report adds information about the beginning of the event and continues with activity through September 2017. Information for this report is provided by Chile's Servicio Nacional de Geología y Minería (SERNAGEOMIN) - Observatorio Volcanológico de Los Andes del Sur (OVDAS), Oficina Nacional de Emergencia - Ministerio del Interior (ONEMI), Corporación Ciudadana Red Nacional de Emergencia (RNE), and by the Buenos Aires Volcanic Ash Advisory Center (VAAC).

Figure (see Caption) Figure 5. This photograph, taken by an astronaut aboard the International Space Station on 11 June 2013, shows three of the largest features of the Nevados de Chillán volcanic complex: Cerro Blanco, Volcán Nuevo, and Volcán Viejo. North is to the lower right. New eruptive activity began in January 2016 from craters located in between Volcán Nuevo and Volcán Viejo.
Figure (see Caption) Figure 6. Detailed location map identifying features of the Nevados de Chillán complex, and the warning zones around the volcano. The colors represent High (maroon), Medium (orange-red), and Low (gold) probabilities of pyroclastic material accumulation of more than one centimeter during a VEI 6 event. Circles with hatch marks inside represent craters. Stars are "Centro de emission,", blue ovals are hot springs. Diagonal cross-hatch is the area most susceptible to pyroclastic material greater than 6.4 cm in diameter in a radius of about 4 km around the active vents. The blue grid lines are spaced four km apart. Courtesy of SERNAGEOMIN, excerpted from Orozco et al. (2016).

Ash emissions at Nevados de Chillán began on 8 January 2016, and were intermittent through September 2017. Four new craters emerged in a NNE trend along the flanks of Volcán Nuevo and Volcán Arrau; two eventually merged into a single 100-m-diameter crater. Most plumes were brief pulses of steam and ash that rose 200-300 m above the craters. Larger events sent a few plumes as high as 2.2 km above the summit (to 5.4 km altitude). Strong prevailing winds quickly dissipated most ash plumes. Periods of multiple small explosions lasted for 1-2 weeks, separated by periods of relative quiet characterized by only steam-and-gas emissions from the active craters and nearby fumarolic centers. The first observable incandescence at the craters was noted in early March 2016. Incandescent bombs were thrown 300 m above the craters during July and September 2016, and 500 m high during March-May 2017 when blocks also fell with 500 m of the craters.

Activity during 2016. After the first explosion with ash emissions on 8 January 2016, nine more pulses of ash were emitted the next day, and small sporadic emissions were reported in the following days (figure 7). OVDAS researchers flew over the volcano on 9 January and concluded that the explosions came from a new crater on the E slope of Volcán Nuevo, about 40 m from the edge of the crater. Researchers from the University of Cambridge who visited the site on 13 January observed continuous degassing at the new 20-m-wide crater. The Buenos Aires VAAC noted puffs of steam and gas dissipating a few hundred meters above the summit (at 3.7 km altitude) in satellite imagery on 16 January 2016. ONEMI reported an ash emission on 29 January that originated from the Arrau crater (see figure 6). During an overflight on 30 January, OVDAS researchers saw occasional explosions from the new crater at Nuevo, as well as activity at a new 30-m-diameter crater about 50 m from the Arrau crater on its NE flank (figure 8). Several fumaroles were also identified on the E flank of Arrau crater.

Figure (see Caption) Figure 7. Ash emission at Nevados de Chillán on 9 January 2016 from the edifice that contains the Nuevo and Arrau craters. The peak to the right is Volcán Viejo. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Advierten nuevo pulso volcánico en el Nevados de Chillán, 9 January 2016).
Figure (see Caption) Figure 8. Photograph showing the Arrau crater at Nevados de Chillán observed during a flyover on 30 January 2016. Ash emissions from a new crater on the NE flank (at right) were reported on 29 January. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Otro cráter más se formó en Nevados de Chillán, 31 January 2016).

During the first two weeks of February 2016, there were 175 episodes of discrete tremor; webcams recorded explosions that ejected material from both craters. The Buenos Aires VAAC reported a brief ash emission on 3 February that dissipated quickly near the summit. During an overflight on 11 February coordinated with ONEMI, scientists identified a third crater, which created a 150-m-long NNE trend with the other two active craters identified during January. During the second half of February, emissions consisted mostly of steam plumes rising no more than 300 m above the crater.

Activity during March 2016 was characterized by steam plumes rising from the active craters; on 3 March, however, a small ash emission was observed. Incandescence was observed in the crater area on the night of 9 March. SERNAGEOMIN reported the beginning of an episode of long-period (LP) seismicity on 18 March, with a pulsating pattern of 3-4 events per minute. During the second half of March, LP and tremor activity was associated with ash emissions. Notably, a low-energy tremor on 30 March lasted for several hours, and concurrently a dense ash plume rose 200 m.

Ash emissions were observed on 7, 8, 9, 18, and 19 April 2016. Plumes were reported rising 400 m on 8 April, and 200 m on 18 and 19 April. Incandescence was observed along with the ash on 18 April. A significant explosion on 9 May 2016 generated an ash plume that rose 1,700 m above the summit (figure 9). The Buenos Aires VAAC reported the ash plume at 3.9 km altitude (700 m above the summit) drifting SE. An overflight by OVDAS on 9 May confirmed the presence of three active craters on the active summit, with the central one having enlarged by 50% since the previous overflight on 11 February. Only pulsating steam emissions were observed in the webcam during the remainder of May and June 2016.

Figure (see Caption) Figure 9. An ash plume rises 1,700 m above the active crater area at Nevados de Chillán after an explosion in the early morning of 9 May 2016. Courtesy of SERNAGEOMIN.

Only steam emissions were reported during the first half of July 2016, but on 21 July an ash-laden emission sent incandescent bombs 300 m above the crater. The Buenos Aires VAAC reported that the webcam showed an ash emission to 3.4 km altitude (200 m above the craters) that day. Webcam Images obtained on 25 July showed debris from an explosion scattered 300 m down the NE flank. During the next few days, ash emissions were inferred from the seismic tremors, but weather conditions prevented direct observations.

During the first two weeks of August 2016, 14 explosions were recorded from the new craters on the E flanks of Nuevo and Arrau. The largest explosion, on 8 August, sent an ash plume 2 km above the crater, according to SERNAGEOMIN (figure 10). The Buenos Aires VAAC reported brief ash emissions on 1, 4, 8, and 9 August at altitudes of 3.7, 3.4, 4.3, and 3.7 km altitude, respectively. Fresh ashfall was visible on the flanks during a flyover on 12 August (figure 11). On the few days when the weather permitted observation of the summit during the remainder of the month, only steam plumes were observed rising no more than 400 m above the crater.

Figure (see Caption) Figure 10. An ash emission at Nevados de Chillán rises 2 km above the active craters on 8 August 2016. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Volcán Nevados de Chillán presenta nuevo pulso eruptive, 8 August 2016).
Figure (see Caption) Figure 11. Fresh ashfall coats the flanks of the active summit at Nevados de Chillán on 12 August 2016, after a large explosion on 8 August. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Registro aéreo muestra actual pulso eruptivo de volcán Nevados de Chillán, 12 August 2016).

Pulsating steam plumes, interrupted by periodic ash emissions, were typical during September 2016. During the first two weeks of the month, 37 recorded explosions were characterized by a high concentration of particulate material. The largest explosion, during the evening of 1 September, generated incandescent bombs for 20 minutes. Incandescence was observed during nighttime explosions a number of times. The Buenos Aires VAAC noted a pilot report of an ash cloud moving SW at 5.2 km altitude on 2 September. They also reported a weak emission of steam and gas with possible diffuse ash visible in the webcam that day. Another pilot report on 6 September indicated an ash cloud moving NE at 6.4 km altitude from a brief but intense emission event around 1420 UTC (figure 12). SERNAGEOMIN noted in their late September report that there had been six explosive episodes since January 2016, with the latest one that occurred during 1-10 September being the strongest.

Figure (see Caption) Figure 12. An ash plume rises from Nevados de Chillán on 6 September 2016. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Volcán Nevados de Chillán registró nuevo pulso eruptive, 6 September 2016).

Explosive activity was recorded on 3, 7, and 8 October 2016 by SERNAGEOMIN; The events were low-energy episodes that emitted small quantities of ash. The Buenos Aires VAAC noted a pilot report on 3 October of an ash cloud moving SE near the summit. It was visible in the webcam but not in satellite imagery, and dissipated quickly. The tallest emission of those days rose to 300 m above the crater on 7 October. During an overflight on 22 October, the continued presence of the three craters along the E flanks of Nueva and Arrau reported previously was confirmed. In addition, the existence of a fourth crater was noted along the same trend as the others. The Buenos Aires VAAC noted ash emissions on 26 and 28 October rising to between 3.7 and 4.3 km altitude and dissipating quickly near the summit.

Seismic activity during the first half of November 2016 included 17 explosions from the active craters. An explosion on 18 November generated an ash plume that rose 1.2 km (figure 13). The Buenos Aires VAAC noted a pilot report of possible ash emissions between 4.6 and 6.1 km altitude on 17 and 27 November, although neither were identified in satellite data.

Figure (see Caption) Figure 13. An ash emission rises 1.2 km above the active crater area at Nevados de Chillán on 18 November 2016. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Sernageomin emite reporte especial por actividad volcánica del complejo Nevados de Chillán, 18 November 2016).

Explosions associated with LP and tremor seismicity continued into December 2016. There were 14 explosive seismic events during the second half of the month, reported by SERNAGEOMIN. The largest occurred on 28 December. The Buenos Aires VAAC noted pilot reports of ash emissions that dissipated near the summit on 13, 28, and 29 December.

Activity during January-September 2017. Explosions related to LP and tremor seismicity increased again on 5 January 2017. The Buenos Aires VAAC reported a dark fumarolic plume drifting E at 4.5 km altitude on 6 January that was observed by a pilot and in the webcam. On 11 and 13 January, the webcam showed sporadic puffs of ash that dissipated very quickly. The largest event occurred on 15 January; the Buenos Aires VAAC reported a narrow plume of ash in satellite imagery at 3.9 km altitude moving W. The webcam also showed sporadic and small puffs that dissipated quickly. An event on 16 January produced an emission that rose 700 m above the crater according to SERNAGEOMIN. This was the last LP-associated explosion of the month. Scientists on a 20 January overflight noted low-intensity steam plumes from the Nuevo and Arrau craters, and from the Chudcún crater which formed in 2003 between them (see figure 6). Yellow and ocher-colored areas, indicating the presence of precipitated sulfur, were visible around the fumaroles and craters.

Low-level degassing rising less than 200 m above the crater was the only surface activity observed during February 2017. A new stage of explosive activity began on 7 March 2017 with emissions that rose as high as 300 m above the crater. The Buenos Aires VAAC noted a pilot report of an ash plume at 3.7 km altitude, and a short-lived puff of ash seen in the webcam. On 11 March, eight explosions sent incandescent blocks up to 0.5 km from the active craters, and emissions rose to 500 m above the crater. Another series of eight explosions on 14 March produced incandescent material and sent an ash plume 1.5 km above the craters. The Buenos Aires VAAC reported intermittent emissions rising up to 4.9 km altitude that day, followed by continuing steam emissions. The following day they noted a small plume near the volcano at 3.9 km altitude visible in satellite data.

During a flyover on 15 March, OVDAS scientists noted that two of the craters (craters 3 and 4) had merged into a single crater 100 m in diameter (figure 14). They also observed five explosions within the space of an hour, the highest resulting plume rose 900 m above the active crater. Webcam images during 16-17 March showed ash emissions rising to 2 km above the crater. The Buenos Aires VAAC reported an ash emission visible in satellite imagery at 5.5 km altitude moving SW on 16 March. For the remainder of the month, only weak degassing under 200 m above the crater was observed. Beginning on 24 March, low-level incandescence at night was reported for the rest of the month.

Figure (see Caption) Figure 14. OVDAS scientists photographed two merged craters (3+4) at Nevados de Chillán on 15 March 2017. They also witnessed five explosions from one crater within an hour (yellow arrow). Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Complejo Volcánico Nevados de Chillán tiene cráter de 100 metros de diámetro, 24 March 2017).

Between 1 and 12 April 2017, there were 56 intermittent explosions marking a new phase of activity according to SERNAGEOMIN. The webcams around the complex imaged emissions up to 3 km above the crater throughout the month. The Buenos Aires VAAC reported sporadic emissions of ash visible in the webcam on 3 and 6-8 April. A faint emission at 3.7 km altitude was spotted in satellite imagery on 10 April. From 16 to 30 April, there were 79 intermittent explosions recorded. During dusk and dawn, incandescent material was observed traveling 600 m down the flanks, with some episodes lasting for 60 minutes. The Buenos Aires VAAC reported a brief ash emission and incandescent material visible in the webcam on 17 April, and sporadic ash emissions that rose to 3.9 km altitude on 21, 29, and 30 April (figure 15).

Figure (see Caption) Figure 15. An ash emission on 30 April 2017 at Nevados de Chillán rose to 3.9 km altitude (700 m above the craters), and was photographed by a twitter user near the volcano. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Nuevo pulso eruptivo de volcán Nevados de Chillán preocupa en la región del Bío Bío, 30 April 2017).

Nine intermittent explosions occurred between 1 and 11 May 2017. The webcams showed emissions from the explosions rising generally 300 m above the craters according to SERNAGEOMIN. Intermittent explosions increased again during 27-31 May. Emissions rose to 1.5 km above the craters and incandescent blocks could be seen traveling 600 m down the flank. Periods of constant incandescence lasted for 30 minutes.

This explosive episode continued into June 2017, with 23 intermittent explosions between 1 and 5 June. The largest emission event on 5 June sent a plume 2.2 km above the craters (figure 16). The Buenos Aires VAAC observed the ash plume at 4.6 km altitude in satellite imagery. During 6-15 June, only steam emissions rising to 300 m were reported. Intermittent explosions on 20, 22, 25, and 26 June produced plumes that rose only 200 m above the craters; cloudy weather prevented observation from the webcams during these events.

Figure (see Caption) Figure 16. Twitter users in Chile shared this image of an ash plume rising from the active craters at Nevados de Chillán with regional authorities on 5 June 2017. The Buenos Aires VAAC reported the plume rising to 4.6 km altitude. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Volcán Nevados de Chillán emite nuevo pulso eruptive, 5 June 2017).

No explosive events were observed in the webcams during the first half of July 2017; only steam plumes rising 200 m were reported. A single low-energy explosion was recorded on 31 July; the emission rose to only 100 m above the crater. During August 2017, there were 83 intermittent explosions associated with ash emissions recorded by SERNAGEOMIN. The emissions rose to about 300 m above the active craters; a few larger emissions rose 1,000 m. The Buenos Aires VAAC noted a pilot report of ash emissions on 17 August; the webcam captured a brief emission that dissipated rapidly.

About 150 intermittent explosions were reported during September 2017. The highest plumes, generally composed of steam and ash, rose 2,000 m above the craters. The Buenos Aires VAAC observed a narrow plume of ash in satellite imagery moving N at 3.9 km altitude and dissipating rapidly on 15 September, and a similar plume moving SE near the summit on 26 September 2017.

Reference: Orozco, G.; Jara, G.; Bertin, D. 2016. Peligros del Complejo Volcánico Nevados de Chillán, Región del Biobío. Servicio Nacional de Geología y Minería, Carta Geológica de Chile, Serie Geología Ambiental 28: 34 p., 1 mapa escala 1:75.000. Santiago.

Information Contacts: Servicio Nacional de Geología y Minería, (SERNAGEOMIN), Observatorio Volcanológico de Los Andes del Sur (OVDAS), Avda Sta María No. 0104, Santiago, Chile ( URL: http://www.sernageomin.cl/); Oficina Nacional de Emergencia - Ministerio del Interior (ONEMI), Beaucheff 1637/1671, Santiago, Chile (URL: http://www.onemi.cl/); Corporación Ciudadana Red Nacional de Emergencia (RNE, Citizen Corporation National Emergency Network), Avda. Vicuña Mackenna Nº3125, San Joaquín, Santiago de Chile, Chile (URL: http://www.reddeemergencia.cl/); Buenos Aires Volcanic Ash Advisory Center (VAAC), Servicio Meteorológico Nacional-Fuerza Aérea Argentina, 25 de mayo 658, Buenos Aires, Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/inicio.php?lang=es).

Weekly Reports - Index


2017: January | March | April | May | August | September | October | December
2016: January | April | May | July | August | September | October | November | December
2015: December
2009: January


6 December-12 December 2017 Citation IconCite this Report


POVI reported that observations of Nevados de Chillán's Volcán Arrau dome complex during 7-11 December indicated phreatic explosions, ash emissions, and a new sulfur deposit on the flank. On 11 December Servicio Nacional de Geología and Minería (SERNAGEOMIN) reported that explosive activity generated an ash plume to 3 km above the complex. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Sources: Proyecto Observación Villarrica Internet (POVI); Servicio Nacional de Geología y Minería (SERNAGEOMIN)


11 October-17 October 2017 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that a series of six pulsating gas-and-tephra emissions from low-energy explosions began at 0843 on 11 October. The plumes rose 1 km and drifted SW. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


20 September-26 September 2017 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that a phreatic explosion at Nevados de Chillán's Volcán Arrau dome complex was recorded by a webcam on 21 September. An explosion ejected gas and tephra on 23 September. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


6 September-12 September 2017 Citation IconCite this Report


According to Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that during 16-31 August phreato-magmatic explosions at Nevados de Chillán's Volcán Arrau dome complex had decreased. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Source: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)


30 August-5 September 2017 Citation IconCite this Report


Based on webcam views, Volcanes de Chile reported that an eruption at Nevados de Chillán occurred around 0925 on 30 August.

Source: Volcanes de Chile


3 May-9 May 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 3 May a webcam recorded a puff rising from Nevados de Chillán and dissipating rapidly.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


26 April-2 May 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 29 April a webcam recorded a puff rising from Nevados de Chillán and dissipating rapidly

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


19 April-25 April 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 21 April a webcam recorded a steam, gas, and ash puff rising from Nevados de Chillán to 4 km (13,000 ft) a.s.l. and dispersing rapidly near the summit.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


12 April-18 April 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 17 April a webcam recorded the ejection of incandescent material from Nevados de Chillán, and a possible ash plume that rose to 3.7 km (12,000 ft) a.s.l.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


5 April-11 April 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 6 and 8 April a webcam recorded ash emissions rising from Nevados de Chillán and dissipating quickly. On 6 April the emissions rose as high as 4 km (13,000 ft) a.s.l. Minor ash emissions were observed on 10 April.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


29 March-4 April 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 3 April a webcam recorded a strong ash puff from Nevados de Chillán rising to an altitude of 4.9 km (16,000 ft) a.s.l. and drifting E.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


22 March-28 March 2017 Citation IconCite this Report


On 24 March OVDAS-SERNAGEOMIN reported that during an overflight of Nevados de Chillán scientists observed a single 100-m-diameter crater, the result of two active craters merging together sometime between 7 and 15 March. In addition there were five explosions in the period of about an hour, ejecting tephra 900 m high which dispersed SE. The pattern of activity changed on 17 March with increased frequency and magnitude of the explosions. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


15 March-21 March 2017 Citation IconCite this Report


Based on satellite and webcam views, the Buenos Aires VAAC reported that during 15-17 March gas-and-ash plumes from Nevados de Chillán rose to altitudes of 4-5.5 km (13,000-18,000 ft) a.s.l. and sometimes drifted NE and SW.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


8 March-14 March 2017 Citation IconCite this Report


OVDAS-SERNAGEOMIN reported that the number of phreatomagmatic explosions at Nevados de Chillán increased on 7 March, after a month and a half of no explosive activity. Explosions from the craters on the E side of Volcán Nuevo and the Volcán Arrau dome complex produced plumes that rose 300 m on 7 March, and then subsequently seismicity and surficial activity gradually increased. On 11 March there were eight explosions detected. Plumes rose as high as 500 m and incandescent material was ejected 500 m away from the craters. A series of eight explosions beginning at 0617 on 16 March generated ash plumes that rose 1.5 km and again ejected incandescent material. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


11 January-17 January 2017 Citation IconCite this Report


The Buenos Aires VAAC reported that on 13 January an ash puff recorded by a webcam rose from Nevados de Chillán and quickly dissipated. On 15 January a narrow ash plume observed in satellite images, by a pilot, and recorded by a webcam drifted W and dissipated.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


4 January-10 January 2017 Citation IconCite this Report


Based on a pilot observation, the Buenos Aires VAAC reported that on 6 January a dark-colored fumarolic plume rose from Nevados de Chillán to an altitude of 2.9 km (9,500 ft) a.s.l. and drifted 4.5 km E. The webcam recorded the event as a small, sporadic puff that quickly dissipated; the emission was not identified in satellite images.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


14 December-20 December 2016 Citation IconCite this Report


According to ONEMI on 16 December, OVDAS-SERNAGEOMIN reported that in recent days there had been sporadic explosions at craters formed at Nevados de Chillán in 2016. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.

Source: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)


16 November-22 November 2016 Citation IconCite this Report


The Buenos Aires VAAC reported that on 18 November an ash puff from Nevados de Chillán was recorded by the webcam. SERNAGEOMIN reported that two explosions, detected at 0536 on 18 November, generated a plume that rose 1.2 km above the crater rim.

Sources: Buenos Aires Volcanic Ash Advisory Center (VAAC); Servicio Nacional de Geología y Minería (SERNAGEOMIN)


26 October-1 November 2016 Citation IconCite this Report


Based on webcam images, the Buenos Aires VAAC reported that on 28 October an ash puff from Nevados de Chillán rose to an altitude of 4.3 km (14,000 ft) a.s.l. and quickly dissipated near the summit.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


28 September-4 October 2016 Citation IconCite this Report


Based on webcam images and pilot observations, the Buenos Aires VAAC reported that on 3 October an ash emission from Nevados de Chillán drifted SE.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


31 August-6 September 2016 Citation IconCite this Report


The Buenos Aires VAAC reported that on 2 September steam-and-gas emissions from Nevados de Chillán possibly contained minor amounts of ash. On 6 September the webcam recorded a short-duration, intense ash emission.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


3 August-9 August 2016 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that the seismic stations monitoring Nevados de Chillán recorded an increase in seismic signals indicating explosions and increased emissions from new craters on the E side of Volcán Nuevo and the Volcán Arrau dome complex. During 1-9 August there were 11 explosions detected; the highest energy signal was recorded at 1656 on 8 August and was accompanied by an emission that rose 2 km. That same day the Buenos Aires VAAC reported that a gas-and-ash puff rose to an altitude of 4.2 km (14,000 ft) a.s.l. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius which had been extended due to the recent activity increase.

Sources: Buenos Aires Volcanic Ash Advisory Center (VAAC); Servicio Nacional de Geología y Minería (SERNAGEOMIN)


27 July-2 August 2016 Citation IconCite this Report


The Buenos Aires VAAC reported that on 1 August a webcam recorded an ash puff from Nevados de Chillán that rose to an altitude of 3.6 km (12,000 ft) a.s.l., and then emissions of gas and minor amounts of ash at crater level.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


20 July-26 July 2016 Citation IconCite this Report


The Buenos Aires VAAC reported that on 21 July a webcam recorded an ash puff from Nevados de Chillán that rose to an altitude of 3 km (10,000 ft) a.s.l., and then continuous emissions of gas and minor amounts of ash that rapidly dissipated at crater level.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


4 May-10 May 2016 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that the seismic stations monitoring Nevados de Chillán's Volcán Arrau dome complex recorded an explosion at 1303 on 9 May; an associated plume rose 1.7 km above the crater rim. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 2-km radius.

Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI); Servicio Nacional de Geología y Minería (SERNAGEOMIN)


13 April-19 April 2016 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that during 1-15 April mostly white vapor emissions rose above Nevados de Chillán's Volcán Arrau dome complex; a small amount of ash was present in the emissions during 7-9 April, rising at most 400 m. The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 2-km radius.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


27 January-2 February 2016 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that at 1425 on 29 January a phreatic explosion at Nevados de Chillán's Volcán Arrau dome complex generated an ash emission that was associated with a seismic tremor signal. During an overflight on 30 January volcanologists observed that the series of recent phreatic explosions had formed a new crater about 50 m from Arrau Crater, on the E flank. The new crater was 25-30 m wide and at a similar elevation as the crater formed on 8 January. The Alert Level remained at Yellow, the middle level on a three-color scale.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


13 January-19 January 2016 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that at 1755 on 8 January a phreatic explosion at Nevados de Chillán generated a short-duration ash emission and was associated with a long-period seismic event. At least one phreatic explosion occurred on 9 January, generating ash emissions. During an overflight that same day volcanologists observed a new crater on the E flank of the Volcán Nuevo lava-dome complex, about 40 m from the edge of the crater. The Alert Level remained at Yellow, the middle level on a three-color scale.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


30 December-5 January 2016 Citation IconCite this Report


Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that increasing seismicity at Nevados de Chillán and increased activity of the hydrothermal system prompted an Alert Level increase to Yellow, on a three-color scale. During 1-31 December the seismic network recorded 1,259 seismic events, including 186 volcano-tectonic events with a maximum local M (LM) of 1.8 located 17 km NNW at a depth of 4 km, 1,030 long-period earthquakes with a maximum LM 1.7, 40 short episodes of spasmodic tremor, and three tornillo-type events. The webcam recorded a small white plume rising from the crater on 9 December.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)


21 January-27 January 2009 Citation IconCite this Report


Based on a SIGMET and analysis of satellite imagery, the Buenos Aires VAAC reported that during 21-22 January ash plumes from Nevados de Chillán rose to altitudes of 3.7-6.1 km (12,000-20,000 ft) a.s.l. and drifted 50-80 km SE. The VAAC also reported that an ash plume from Callaqui, a nearby volcano 120 km S, drifted NE on 22 January.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)


Bulletin Reports - Index


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

07/1979 (SEAN 04:07) Eruption continuing since 1973

03/2004 (BGVN 29:03) A small eruption, the first since 1986, during August-September 2003

06/2016 (BGVN 41:06) Eruptive episode begins in January 2016 with phreatic explosions

10/2017 (BGVN 42:10) Intermittent ash emissions from new craters along the E flanks of Volcáns Nuevo and Arrau persist through September 2017




Information is preliminary and subject to change. All times are local (unless otherwise noted)


July 1979 (SEAN 04:07) Citation IconCite this Report


Eruption continuing since 1973

When visited by Oscar González-Ferrán on 21 February 1979, the eruption of Nevados de Chillán that began in July 1973 was continuing. An explosion lasting 1.5 hours produced a cloud, containing bombs, [blocks], and ash, that rose almost 2 km before reaching a windy layer that prevented further upward movement. The new cone had grown to about the same height as the adjacent 1906 cone [Volcán Nuevo], where fumarolic activity persisted (figure 1).

Figure (see Caption) Figure 1. Sketch of the Nevados de Chillán complex; the upper sketch shows details of the area active on 21 February 1979. Courtesy of Oscar González-Ferrán.

[Hugo Moreno reports that by 1983 the phreatomagmatic eruption had almost ended. From 1983 to 1987, only a few explosions have been reported (about one every 2 months). These generated small pyroclastic flows, by column collapse, over the snow cover. By late 1987, the dome extruded earlier in the eruption had been covered by tephra that built a new cone (named Tata) about 30 m higher than neighboring Volcán Nuevo.]

Further Reference. Deruelle, B., 1977, New activity of the Nevados de Chillán: C.R. Acad. Sci. Paris, serie D, v. 284, p. 1651-1654.

Information Contacts: O. González-Ferrán, Univ. de Chile, Santiago.


March 2004 (BGVN 29:03) Citation IconCite this Report


A small eruption, the first since 1986, during August-September 2003

Nevados de Chillán was active from 1973 through 1983; after that, phreatomagmatic eruptions were reported to have almost ended. A small (VEI 1) eruption, the first since 1986, was noted by local inhabitants and tourists in August-September 2003. Low magnitude explosive events occurred over the week ending 27 August 2003, sending brown-gray to white gas-and-ash columns up to heights of 500 m for periods of up to 25 minutes. Resulting deposits were ~ 1 cm deep over a sharply defined 2.2 km wide zone to the SSE. Prevailing winds were strong around the time of the eruption (figure 2). Explosions then became more sporadic, occurring at 2-3 day intervals, until ceasing in mid-September.

Figure (see Caption) Figure 2. Strong prevailing winds blowing over the Nevados de Chillán complex caused the resulting plume to remain at low altitude. This photo was taken in early September 2003. The plume blew towards the SSE. Courtesy Servicio Nacional de Geoligica y Mineria.

An inspection of the eruption site on 22 January 2004 by Servicio Nacional de Geoligica y Mineria scientists revealed a new compound, fissure-like, double crater in the saddle between the cones Nuevo (which erupted during 1906-1945) and Arrau (which erupted during 1973-1986) (figure 3). This new ~ 64 m long double crater consisted of a NW situated, 25 x 14 m crater and a SE situated, 39 x 28 m crater. These craters lie to the NW of Arrau cone and become surrounded by an area of intense fumaroles towards Nuevo cone. The fumaroles are water-vapor rich but give off a weak sulfur odor. On Nuevo's E side they had temperatures of up to 88°C (table 1). While no previous measurements were available, this area showed more intense fumarolic activity than seen during a January 1994 visit and 1998 air photographs. During the recent visit the local heat-flow appeared concentrated adjacent to Nuevo cone, rather than Arrau cone. This, and the fissure-like form of the 2003 crater, were taken as evidence for possible future eruptions closer to Nuevo cone.

Figure (see Caption) Figure 3. Aerial view and cross section of the Nevados de Chillán complex, showing the new crater in relation to Nuevo and Arrau cones, and indicating SSE-oriented ash dispersal. Courtesy Servicio Nacional de Geoligica y Mineria.

Table 1. Site names, locations (as UTM coordinates), and fumarole temperatures describing conditions at Nevados de Chillán on 22 January 2004. The fumaroles were located near the 2003 vent. Courtesy of J.A. Naranjo and L.E. Lara, SERNAGEOMIN.

Site UTM N UTM W Temperature (°C ± 0.5)
SW Nuevo flank 288.086 5916.963 87.2
E Nuevo rim 288.138 5917.522 87.9
Between craters 288.263 5917.547 57.4

In addition to dispersal and deposition of loose ash, the January inspection noted agglutinates forming a series of 2 m long ridges or 'dunes' (figure 4). The agglutinates consisted of wet black clusters of ash spheres with 0.5- to 1-cm diameters. A large number of dead insects in the agglutinated ash suggested extreme conditions such as the presence of toxic gasses. When dry, the ash was dark gray with a lithic-rich polymodal composition. Particle sizes ranged from dust to 4-5 mm, of which 5-10% was coarse-grained, lithic-rich lapilli composed of black, gray, and red aphyric andesites and ~ 60% was fine- to medium-grained lapilli composed of lithic clasts, quartz, and plagioclase crystals. Below the 1 mm size range, black glassy shards appeared with cleaved vesicle surfaces and blocky or plate-like shapes. The remnant fraction was light-gray fine ash.

Figure (see Caption) Figure 4. January 2004 view of dried ash deposits from Nevados de Chillán's 2003 eruption. The darker deposits lay atop remnant snow pack. Courtesy Servicio Nacional de Geoligica y Mineria.

Reference. Naranjo, J.A., and Lara, L.E., 2004, August-September 2003 small vulcanian eruption at the Nevados de Chillán Volcanic Complex (36°50'S), Southern Andes (Chile). Revista Geológica de Chile, Vol. 31, No. 2, p. 359-366. DOI: 10.4067/S0716-02082004000200011.

Information Contacts: Jose A. Naranjo and Luis E. Lara, Servicio Nacional de Geoligica y Mineria (SERNAGEOMIN), Av. Santa Maria 0104, Santiago, Chile.


June 2016 (BGVN 41:06) Citation IconCite this Report


Eruptive episode begins in January 2016 with phreatic explosions

A small eruption from Nevados de Chillán during August-September 2003 was the first since 1986 (BGVN 29:03). Subsequent activity included ash plumes in 2009, and since December 2015, heightened seismic activity, phreatic explosions, and gas and steam emissions from fumaroles. Nevados de Chillán is a group of stratovolcanoes with Cerro Blanco (Volcán Nevado) at the NW end, Volcán Viejo (Volcán Chillán) at the SE end, with a group of lava domes known as Volcán Nuevo in the middle; the 1973-1986 Volcán Arrau dome complex is SE of Volcán Nuevo.

This report covers activity from 2009 through May 2016. With the exception of the Buenos Aires Volcanic Ash Advisory Center (VAAC) report in January 2009, all of the information has been provided by Chile's Servicio Nacional de Geología y Minería (SERNAGEOMIN) - Observatorio Volcanológico de Los Andes del Sur (OVDAS).

Based on Significant Meteorological Information (SIGMET) and analysis of satellite imagery, the Buenos Aires VAAC reported that during 21-22 January 2009, ash plumes rose to altitudes of 3.7-6.1 km and drifted 50-80 km SE. No other information or ground confirmation of ash emission is available about this activity, and no other activity was reported over the next seven years.

The webcam recorded a small white plume on 9 December 2015 rising from the crater. On 31 December 2015, SERNAGEOMIN-OVDAS reported that both seismicity and hydrothermal system activity had increased, prompting an elevation of the Alert Level to Yellow (on a 3-color scale). They also noted the installation of two new seismic stations as well as three GPS stations, with real-time transmission. During December 2015 the seismic network recorded 1,259 seismic events, including 186 volcano-tectonic (VT) earthquakes, 1,030 long-period (LP) earthquakes, 40 short episodes of spasmodic tremor, and three tornillo-type events. The majority of these events were concentrated around the southern cone of the complex at a depth of less than 5 km.

A phreatic explosion at 1755 on 8 January 2016, associated with an LP earthquake, generated a short-duration ash emission. At least one additional phreatic ash explosion occurred on 9 January. During an overflight that same day, volcanologists observed a new crater on the E flank of the Volcán Nuevo lava-dome complex, about 40 m from the edge of the crater. On 29 January a phreatic explosion at 1425 from the Arrau dome complex generated an ash emission that was associated with a seismic tremor signal. During an overflight on 30 January, volcanologists observed that the series of recent phreatic explosions had formed a new crater about 50 m from Arrau Crater, on the E flank. The new crater was 25-30 m wide and at a similar elevation as the crater formed on 8 January.

Monitoring stations registered a VT earthquake at 0635 on 11 February 2016, located 5.3 km SE of Chillán at a depth of 1 km. During 16-29 February 2016, the seismic network recorded 579 seismic events, including 65 VT earthquakes, 510 LP earthquakes, and four discreet tremors. Webcams showed steam emissions from a small fumarole rising to a maximum height of 300 m above the crater.

On 18 March 2016 the number of LP earthquakes increased to 3-4 events per minute starting at 0844. During 1-15 April steam rose from the Arrau dome complex; a small amount of ash was present in the emissions during 7-9 April, rising at most 400 m. On 9 May at 1303, seismic stations recorded an explosion that generated a plume that rose 1.7 km above the crater rim.

Information Contacts: Servicio Nacional de Geología y Minería (SERNAGEOMIN) (URL: http://www.sernageomin.cl/volcanes.php); Observatorio Volcanológico de los Andes del Sur (OVDAS), Temuco (URL: http://www.sernageomin.cl/volcan-observatorio.php); Oficina Nacional de Emergencia Ministerio del Interior (ONEMI) (URL: http://www.onemi.cl/); Buenos Aires Volcanic Ash Advisory Center (VAAC), Servicio Meteorológico Nacional-Fuerza Aérea Argentina, 25 de mayo 658, Buenos Aires, Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/inicio.php?lang=es).


October 2017 (BGVN 42:10) Citation IconCite this Report


Intermittent ash emissions from new craters along the E flanks of Volcáns Nuevo and Arrau persist through September 2017

Nevados de Chillán, in the Chilean Central Andes, is a complex of late-Pleistocene to Holocene stratovolcanoes constructed along a NNW-SSE trend (figure 5). The Nuevo and Arrau craters, active during 1906-1945 and 1973-1986, respectively, are adjacent vents on the NW cone of a large stratovolcano complex 5 km SE of Cerro Blanco; the summit 1 km SE of Arrau is named Volcán Viejo (figure 6). A short eruption during August-September 2003 created a new fissure vent between the Nuevo and Arrau craters (BGVN 29:03, figure 3). Increased seismicity and fumarolic activity were recorded during December 2015, and a new eruption started with a phreatic explosion and ash emission on 8 January 2016 from a new crater on the E flank of Nuevo cones (BGVN 41:06). This report adds information about the beginning of the event and continues with activity through September 2017. Information for this report is provided by Chile's Servicio Nacional de Geología y Minería (SERNAGEOMIN) - Observatorio Volcanológico de Los Andes del Sur (OVDAS), Oficina Nacional de Emergencia - Ministerio del Interior (ONEMI), Corporación Ciudadana Red Nacional de Emergencia (RNE), and by the Buenos Aires Volcanic Ash Advisory Center (VAAC).

Figure (see Caption) Figure 5. This photograph, taken by an astronaut aboard the International Space Station on 11 June 2013, shows three of the largest features of the Nevados de Chillán volcanic complex: Cerro Blanco, Volcán Nuevo, and Volcán Viejo. North is to the lower right. New eruptive activity began in January 2016 from craters located in between Volcán Nuevo and Volcán Viejo.
Figure (see Caption) Figure 6. Detailed location map identifying features of the Nevados de Chillán complex, and the warning zones around the volcano. The colors represent High (maroon), Medium (orange-red), and Low (gold) probabilities of pyroclastic material accumulation of more than one centimeter during a VEI 6 event. Circles with hatch marks inside represent craters. Stars are "Centro de emission,", blue ovals are hot springs. Diagonal cross-hatch is the area most susceptible to pyroclastic material greater than 6.4 cm in diameter in a radius of about 4 km around the active vents. The blue grid lines are spaced four km apart. Courtesy of SERNAGEOMIN, excerpted from Orozco et al. (2016).

Ash emissions at Nevados de Chillán began on 8 January 2016, and were intermittent through September 2017. Four new craters emerged in a NNE trend along the flanks of Volcán Nuevo and Volcán Arrau; two eventually merged into a single 100-m-diameter crater. Most plumes were brief pulses of steam and ash that rose 200-300 m above the craters. Larger events sent a few plumes as high as 2.2 km above the summit (to 5.4 km altitude). Strong prevailing winds quickly dissipated most ash plumes. Periods of multiple small explosions lasted for 1-2 weeks, separated by periods of relative quiet characterized by only steam-and-gas emissions from the active craters and nearby fumarolic centers. The first observable incandescence at the craters was noted in early March 2016. Incandescent bombs were thrown 300 m above the craters during July and September 2016, and 500 m high during March-May 2017 when blocks also fell with 500 m of the craters.

Activity during 2016. After the first explosion with ash emissions on 8 January 2016, nine more pulses of ash were emitted the next day, and small sporadic emissions were reported in the following days (figure 7). OVDAS researchers flew over the volcano on 9 January and concluded that the explosions came from a new crater on the E slope of Volcán Nuevo, about 40 m from the edge of the crater. Researchers from the University of Cambridge who visited the site on 13 January observed continuous degassing at the new 20-m-wide crater. The Buenos Aires VAAC noted puffs of steam and gas dissipating a few hundred meters above the summit (at 3.7 km altitude) in satellite imagery on 16 January 2016. ONEMI reported an ash emission on 29 January that originated from the Arrau crater (see figure 6). During an overflight on 30 January, OVDAS researchers saw occasional explosions from the new crater at Nuevo, as well as activity at a new 30-m-diameter crater about 50 m from the Arrau crater on its NE flank (figure 8). Several fumaroles were also identified on the E flank of Arrau crater.

Figure (see Caption) Figure 7. Ash emission at Nevados de Chillán on 9 January 2016 from the edifice that contains the Nuevo and Arrau craters. The peak to the right is Volcán Viejo. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Advierten nuevo pulso volcánico en el Nevados de Chillán, 9 January 2016).
Figure (see Caption) Figure 8. Photograph showing the Arrau crater at Nevados de Chillán observed during a flyover on 30 January 2016. Ash emissions from a new crater on the NE flank (at right) were reported on 29 January. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Otro cráter más se formó en Nevados de Chillán, 31 January 2016).

During the first two weeks of February 2016, there were 175 episodes of discrete tremor; webcams recorded explosions that ejected material from both craters. The Buenos Aires VAAC reported a brief ash emission on 3 February that dissipated quickly near the summit. During an overflight on 11 February coordinated with ONEMI, scientists identified a third crater, which created a 150-m-long NNE trend with the other two active craters identified during January. During the second half of February, emissions consisted mostly of steam plumes rising no more than 300 m above the crater.

Activity during March 2016 was characterized by steam plumes rising from the active craters; on 3 March, however, a small ash emission was observed. Incandescence was observed in the crater area on the night of 9 March. SERNAGEOMIN reported the beginning of an episode of long-period (LP) seismicity on 18 March, with a pulsating pattern of 3-4 events per minute. During the second half of March, LP and tremor activity was associated with ash emissions. Notably, a low-energy tremor on 30 March lasted for several hours, and concurrently a dense ash plume rose 200 m.

Ash emissions were observed on 7, 8, 9, 18, and 19 April 2016. Plumes were reported rising 400 m on 8 April, and 200 m on 18 and 19 April. Incandescence was observed along with the ash on 18 April. A significant explosion on 9 May 2016 generated an ash plume that rose 1,700 m above the summit (figure 9). The Buenos Aires VAAC reported the ash plume at 3.9 km altitude (700 m above the summit) drifting SE. An overflight by OVDAS on 9 May confirmed the presence of three active craters on the active summit, with the central one having enlarged by 50% since the previous overflight on 11 February. Only pulsating steam emissions were observed in the webcam during the remainder of May and June 2016.

Figure (see Caption) Figure 9. An ash plume rises 1,700 m above the active crater area at Nevados de Chillán after an explosion in the early morning of 9 May 2016. Courtesy of SERNAGEOMIN.

Only steam emissions were reported during the first half of July 2016, but on 21 July an ash-laden emission sent incandescent bombs 300 m above the crater. The Buenos Aires VAAC reported that the webcam showed an ash emission to 3.4 km altitude (200 m above the craters) that day. Webcam Images obtained on 25 July showed debris from an explosion scattered 300 m down the NE flank. During the next few days, ash emissions were inferred from the seismic tremors, but weather conditions prevented direct observations.

During the first two weeks of August 2016, 14 explosions were recorded from the new craters on the E flanks of Nuevo and Arrau. The largest explosion, on 8 August, sent an ash plume 2 km above the crater, according to SERNAGEOMIN (figure 10). The Buenos Aires VAAC reported brief ash emissions on 1, 4, 8, and 9 August at altitudes of 3.7, 3.4, 4.3, and 3.7 km altitude, respectively. Fresh ashfall was visible on the flanks during a flyover on 12 August (figure 11). On the few days when the weather permitted observation of the summit during the remainder of the month, only steam plumes were observed rising no more than 400 m above the crater.

Figure (see Caption) Figure 10. An ash emission at Nevados de Chillán rises 2 km above the active craters on 8 August 2016. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Volcán Nevados de Chillán presenta nuevo pulso eruptive, 8 August 2016).
Figure (see Caption) Figure 11. Fresh ashfall coats the flanks of the active summit at Nevados de Chillán on 12 August 2016, after a large explosion on 8 August. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Registro aéreo muestra actual pulso eruptivo de volcán Nevados de Chillán, 12 August 2016).

Pulsating steam plumes, interrupted by periodic ash emissions, were typical during September 2016. During the first two weeks of the month, 37 recorded explosions were characterized by a high concentration of particulate material. The largest explosion, during the evening of 1 September, generated incandescent bombs for 20 minutes. Incandescence was observed during nighttime explosions a number of times. The Buenos Aires VAAC noted a pilot report of an ash cloud moving SW at 5.2 km altitude on 2 September. They also reported a weak emission of steam and gas with possible diffuse ash visible in the webcam that day. Another pilot report on 6 September indicated an ash cloud moving NE at 6.4 km altitude from a brief but intense emission event around 1420 UTC (figure 12). SERNAGEOMIN noted in their late September report that there had been six explosive episodes since January 2016, with the latest one that occurred during 1-10 September being the strongest.

Figure (see Caption) Figure 12. An ash plume rises from Nevados de Chillán on 6 September 2016. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Volcán Nevados de Chillán registró nuevo pulso eruptive, 6 September 2016).

Explosive activity was recorded on 3, 7, and 8 October 2016 by SERNAGEOMIN; The events were low-energy episodes that emitted small quantities of ash. The Buenos Aires VAAC noted a pilot report on 3 October of an ash cloud moving SE near the summit. It was visible in the webcam but not in satellite imagery, and dissipated quickly. The tallest emission of those days rose to 300 m above the crater on 7 October. During an overflight on 22 October, the continued presence of the three craters along the E flanks of Nueva and Arrau reported previously was confirmed. In addition, the existence of a fourth crater was noted along the same trend as the others. The Buenos Aires VAAC noted ash emissions on 26 and 28 October rising to between 3.7 and 4.3 km altitude and dissipating quickly near the summit.

Seismic activity during the first half of November 2016 included 17 explosions from the active craters. An explosion on 18 November generated an ash plume that rose 1.2 km (figure 13). The Buenos Aires VAAC noted a pilot report of possible ash emissions between 4.6 and 6.1 km altitude on 17 and 27 November, although neither were identified in satellite data.

Figure (see Caption) Figure 13. An ash emission rises 1.2 km above the active crater area at Nevados de Chillán on 18 November 2016. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Sernageomin emite reporte especial por actividad volcánica del complejo Nevados de Chillán, 18 November 2016).

Explosions associated with LP and tremor seismicity continued into December 2016. There were 14 explosive seismic events during the second half of the month, reported by SERNAGEOMIN. The largest occurred on 28 December. The Buenos Aires VAAC noted pilot reports of ash emissions that dissipated near the summit on 13, 28, and 29 December.

Activity during January-September 2017. Explosions related to LP and tremor seismicity increased again on 5 January 2017. The Buenos Aires VAAC reported a dark fumarolic plume drifting E at 4.5 km altitude on 6 January that was observed by a pilot and in the webcam. On 11 and 13 January, the webcam showed sporadic puffs of ash that dissipated very quickly. The largest event occurred on 15 January; the Buenos Aires VAAC reported a narrow plume of ash in satellite imagery at 3.9 km altitude moving W. The webcam also showed sporadic and small puffs that dissipated quickly. An event on 16 January produced an emission that rose 700 m above the crater according to SERNAGEOMIN. This was the last LP-associated explosion of the month. Scientists on a 20 January overflight noted low-intensity steam plumes from the Nuevo and Arrau craters, and from the Chudcún crater which formed in 2003 between them (see figure 6). Yellow and ocher-colored areas, indicating the presence of precipitated sulfur, were visible around the fumaroles and craters.

Low-level degassing rising less than 200 m above the crater was the only surface activity observed during February 2017. A new stage of explosive activity began on 7 March 2017 with emissions that rose as high as 300 m above the crater. The Buenos Aires VAAC noted a pilot report of an ash plume at 3.7 km altitude, and a short-lived puff of ash seen in the webcam. On 11 March, eight explosions sent incandescent blocks up to 0.5 km from the active craters, and emissions rose to 500 m above the crater. Another series of eight explosions on 14 March produced incandescent material and sent an ash plume 1.5 km above the craters. The Buenos Aires VAAC reported intermittent emissions rising up to 4.9 km altitude that day, followed by continuing steam emissions. The following day they noted a small plume near the volcano at 3.9 km altitude visible in satellite data.

During a flyover on 15 March, OVDAS scientists noted that two of the craters (craters 3 and 4) had merged into a single crater 100 m in diameter (figure 14). They also observed five explosions within the space of an hour, the highest resulting plume rose 900 m above the active crater. Webcam images during 16-17 March showed ash emissions rising to 2 km above the crater. The Buenos Aires VAAC reported an ash emission visible in satellite imagery at 5.5 km altitude moving SW on 16 March. For the remainder of the month, only weak degassing under 200 m above the crater was observed. Beginning on 24 March, low-level incandescence at night was reported for the rest of the month.

Figure (see Caption) Figure 14. OVDAS scientists photographed two merged craters (3+4) at Nevados de Chillán on 15 March 2017. They also witnessed five explosions from one crater within an hour (yellow arrow). Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Complejo Volcánico Nevados de Chillán tiene cráter de 100 metros de diámetro, 24 March 2017).

Between 1 and 12 April 2017, there were 56 intermittent explosions marking a new phase of activity according to SERNAGEOMIN. The webcams around the complex imaged emissions up to 3 km above the crater throughout the month. The Buenos Aires VAAC reported sporadic emissions of ash visible in the webcam on 3 and 6-8 April. A faint emission at 3.7 km altitude was spotted in satellite imagery on 10 April. From 16 to 30 April, there were 79 intermittent explosions recorded. During dusk and dawn, incandescent material was observed traveling 600 m down the flanks, with some episodes lasting for 60 minutes. The Buenos Aires VAAC reported a brief ash emission and incandescent material visible in the webcam on 17 April, and sporadic ash emissions that rose to 3.9 km altitude on 21, 29, and 30 April (figure 15).

Figure (see Caption) Figure 15. An ash emission on 30 April 2017 at Nevados de Chillán rose to 3.9 km altitude (700 m above the craters), and was photographed by a twitter user near the volcano. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Nuevo pulso eruptivo de volcán Nevados de Chillán preocupa en la región del Bío Bío, 30 April 2017).

Nine intermittent explosions occurred between 1 and 11 May 2017. The webcams showed emissions from the explosions rising generally 300 m above the craters according to SERNAGEOMIN. Intermittent explosions increased again during 27-31 May. Emissions rose to 1.5 km above the craters and incandescent blocks could be seen traveling 600 m down the flank. Periods of constant incandescence lasted for 30 minutes.

This explosive episode continued into June 2017, with 23 intermittent explosions between 1 and 5 June. The largest emission event on 5 June sent a plume 2.2 km above the craters (figure 16). The Buenos Aires VAAC observed the ash plume at 4.6 km altitude in satellite imagery. During 6-15 June, only steam emissions rising to 300 m were reported. Intermittent explosions on 20, 22, 25, and 26 June produced plumes that rose only 200 m above the craters; cloudy weather prevented observation from the webcams during these events.

Figure (see Caption) Figure 16. Twitter users in Chile shared this image of an ash plume rising from the active craters at Nevados de Chillán with regional authorities on 5 June 2017. The Buenos Aires VAAC reported the plume rising to 4.6 km altitude. Courtesy of Corporación Ciudadana Red Nacional de Emergencia (RNE) (Volcán Nevados de Chillán emite nuevo pulso eruptive, 5 June 2017).

No explosive events were observed in the webcams during the first half of July 2017; only steam plumes rising 200 m were reported. A single low-energy explosion was recorded on 31 July; the emission rose to only 100 m above the crater. During August 2017, there were 83 intermittent explosions associated with ash emissions recorded by SERNAGEOMIN. The emissions rose to about 300 m above the active craters; a few larger emissions rose 1,000 m. The Buenos Aires VAAC noted a pilot report of ash emissions on 17 August; the webcam captured a brief emission that dissipated rapidly.

About 150 intermittent explosions were reported during September 2017. The highest plumes, generally composed of steam and ash, rose 2,000 m above the craters. The Buenos Aires VAAC observed a narrow plume of ash in satellite imagery moving N at 3.9 km altitude and dissipating rapidly on 15 September, and a similar plume moving SE near the summit on 26 September 2017.

Reference: Orozco, G.; Jara, G.; Bertin, D. 2016. Peligros del Complejo Volcánico Nevados de Chillán, Región del Biobío. Servicio Nacional de Geología y Minería, Carta Geológica de Chile, Serie Geología Ambiental 28: 34 p., 1 mapa escala 1:75.000. Santiago.

Information Contacts: Servicio Nacional de Geología y Minería, (SERNAGEOMIN), Observatorio Volcanológico de Los Andes del Sur (OVDAS), Avda Sta María No. 0104, Santiago, Chile ( URL: http://www.sernageomin.cl/); Oficina Nacional de Emergencia - Ministerio del Interior (ONEMI), Beaucheff 1637/1671, Santiago, Chile (URL: http://www.onemi.cl/); Corporación Ciudadana Red Nacional de Emergencia (RNE, Citizen Corporation National Emergency Network), Avda. Vicuña Mackenna Nº3125, San Joaquín, Santiago de Chile, Chile (URL: http://www.reddeemergencia.cl/); Buenos Aires Volcanic Ash Advisory Center (VAAC), Servicio Meteorológico Nacional-Fuerza Aérea Argentina, 25 de mayo 658, Buenos Aires, Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/inicio.php?lang=es).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History


There is data available for 32 Holocene eruptive periods.


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2016 Jan 8 2017 May 3 Confirmed 2 Historical Observations
[ 2009 Jan 21 ] [ 2009 Jan 22 ] Uncertain    
2003 Aug 29 2003 Sep 15 ± 5 days Confirmed 1 Historical Observations Saddle between Nuevo & Arrau volcanoes
1973 Jul 16 ± 15 days 1986 Jul 2 ± 182 days Confirmed 2 Historical Observations Volcán Arrau (SE flank of Volcán Nuevo)
[ 1972 Jul 2 ± 182 days ] [ Unknown ] Uncertain     Volcán Nuevo
[ 1965 Jul 2 ± 182 days ] [ Unknown ] Uncertain     Volcán Nuevo
1946 1947 Confirmed 2 Historical Observations Volcán Nuevo
[ 1945 ] [ Unknown ] Uncertain     Volcán Nuevo
1935 Jul 2 Unknown Confirmed 2 Historical Observations West flank of Volcán Viejo
1934 Jan 17 Unknown Confirmed 2 Historical Observations Volcán Nuevo
1928 Nov 30 1929 Confirmed 2 Historical Observations Volcán Nuevo
1927 Apr 10 Unknown Confirmed 2 Historical Observations Volcán Nuevo
[ 1923 ] [ Unknown ] Uncertain 2   Volcán Nuevo
1914 Unknown Confirmed 2 Historical Observations Volcán Nuevo
1907 Unknown Confirmed 1 Historical Observations Volcán Nuevo
1906 Aug 6 1906 Dec Confirmed 2 Historical Observations Volcán Nuevo
1898 Unknown Confirmed 2 Historical Observations Volcán Viejo
1893 Mar 4 Unknown Confirmed 2 Historical Observations Volcán Viejo
1891 Feb Unknown Confirmed 2 Historical Observations Volcán Viejo
[ 1883 Jan 21 ] [ Unknown ] Uncertain 2   Volcán Viejo (Volcán las Aguilas?)
1877 Feb 12 (?) Unknown Confirmed 2 Historical Observations Volcán Chillán
1872 Jul 22 Unknown Confirmed 2 Historical Observations Volcán Chillán
1864 Nov 30 1865 Feb 3 ± 1 days Confirmed 3 Historical Observations NW flank of Cerro Blanco (Santa Gertrudis)
1861 Jun 1863 Confirmed 2 Historical Observations NW flank of Cerro Blanco (Santa Gertrudis)
1860 Jul 25 Unknown Confirmed 2 Historical Observations W flank of Volcán Viejo (Volcán Renegado)
1752 Jan 30 Unknown Confirmed 2 Historical Observations Cerro Blanco and Volcán Viejo?
1749 (?) 1751 Confirmed 3 Historical Observations Volcán Viejo
1650 ± 50 years Unknown Confirmed 3 Historical Observations Volcán Viejo
0320 BCE ± 75 years Unknown Confirmed   Radiocarbon (uncorrected) Volcán Viejo
1510 BCE ± 50 years Unknown Confirmed   Radiocarbon (uncorrected) Volcán Viejo
3660 BCE ± 500 years Unknown Confirmed   Radiocarbon (uncorrected) Volcán Viejo
6890 BCE ± 500 years Unknown Confirmed   Radiocarbon (uncorrected) Volcán Viejo

Deformation History


There is data available for 1 deformation periods. Expand each entry for additional details.


Deformation during 2010 Feb 27 - 2010 Feb 27 [Subsidence; Observed by InSAR]

Start Date: 2010 Feb 27 Stop Date: 2010 Feb 27 Direction: Subsidence Method: InSAR
Magnitude: 12.000 cm Spatial Extent: 15.00 km Latitude: -37.000 Longitude: -71.000

Remarks: Short-lived subsidence triggered by the Mw 8.8 2010 Maule earthquake

Volcanic ground subsidence observed in interferogram stacks spanning the earthquake (with earthquake effects removed). We assume the ground displacement is of short duration compared to the interferogram time span, so we compute the stack by summing the interferograms and dividing by the number of measurements in the stack for each pixel.

From: Pritchard et al. 2013.


Reference List: Pritchard et al. 2013.

Full References:

Pritchard, M. E., J. A. Jay, F. Aron, S. T. Henderson, and L. E. Lara, 2013. Subsidence at southern Andes volcanoes induced by the 2010 Maule, Chile earthquake. Nature Geoscience, 6: 632-636. http://dx.doi.org/10.1038/ngeo1855

Emission History


There is no Emissions History data available for Nevados de Chillán.

Photo Gallery


Volcán Nuevo, the newest cone of the three-peaked Nevados de Chillán volcano, was formed beginning in 1861. It grew between Cerro Blanco and Volcán Viejo, which anchor the NW and SE ends of the complex, respectively. Volcán Nuevo has been the most active volcano of the complex since its birth. In 1973, the year of this photo, a long-term eruption began on the SE flank of Volcán Nuevo, producing a cone that by 1987 had grown above Volcán Nuevo. Nevados de Chillán is one of the most active volcanoes of the Central Andes of Chile.

Photo by Hugo Moreno, 1973 (University of Chile).
See title for photo information.
Long-term phreatomagmatic eruptions accompanying formation of a new lava dome on the SE flank of Volcán Nuevo began in 1973. This photo shows a small explosive eruption on February 21, 1979. Activity died down in 1983, when intermittent explosions (about one every two months) began. This continued into 1987, by which time the new cone was about 30 m taller than Volcán Nuevo.

Photo by Oscar González-Ferrán, 1979 (University of Chile).
See title for photo information.

Smithsonian Sample Collections Database


There are no samples for Nevados de Chillán in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites