Bulletin of the Global Volcanism Network

All reports of volcanic activity published by the Smithsonian since 1968 are available through a monthly table of contents or by searching for a specific volcano. Until 1975, reports were issued for individual volcanoes as information became available; these have been organized by month for convenience. Later publications were done in a monthly newsletter format. Links go to the profile page for each volcano with the Bulletin tab open.

Information is preliminary at time of publication and subject to change.

 Bulletin of the Global Volcanism Network - Volume 41, Number 04 (April 2016)


Managing Editor: Edward Venzke

Bagana (Papua New Guinea)

Ongoing ash plumes and thermal anomalies through early 2016

Kanlaon (Philippines)

Sporadic ash explosions during November-December 2015 and March 2016



Bagana (Papua New Guinea) — April 2016 Citation iconCite this Report

Bagana

Papua New Guinea

6.137°S, 155.196°E; summit elev. 1855 m

All times are local (unless otherwise noted)


Ongoing ash plumes and thermal anomalies through early 2016

Bagana is one of the most active volcanoes in Papua New Guinea, and has been in eruption since at least early 2000 (BGVN 39:06). It is monitored by the Rabaul Volcano Observatory (RVO) and the Darwin Volcanic Ash Advisory Centre (VAAC), though reports are often fragmentary and based on distant observers or satellite remote sensing. The last recorded lava flow was emplaced sometime between March 2011 and February 2012 (BGVN 39:06), and an ash plume on 10 August 2014 rose to 7.6 km altitude (BGVN 39:12). Intermittent ash plumes rising to 2.5 km were reported for the rest of 2014.

During January 2015 thru February 2016 there were no reports from RVO, so the primary data sources for activity at the volcano were Darwin VAAC, MODIS/MODVOLC, and MIROVA data. The volcano exhibited intermittent low level eruptive activity characterized by ash plumes and thermal anomalies, and was not quiet for more than a month at a time during this period.

During 20-21 January 2015, ash plumes to 3.7 km, drifting up to 35 km NE and SW, were reported by Darwin VAAC. MODVOLC thermal anomalies were also observed on 18 and 20 January. While no activity was recorded for February, there were continuous VAAC reports from 25 March through 1 April. The ash plumes were reported at 2-3 km altitude, and drifting 35-75 km N, NE, and SE. Only one thermal anomaly, on 16 March, was reported that month. Although no VAAC reports or MODVOLC thermal data were recorded in April and early May, MIROVA data (figure 25) indicated a low level of ongoing activity during this time.

Activity picked up again in late May 2015 with more extensive MODVOLC thermal anomalies of multiple pixels on 21 and 22 May, and then more intermittent data on 23, 24, 26, 28, 30 May and 2 June. The first VAAC report during this interval was on 27 May with a plume reported to 3 km, drifting 160 km NW. Additional thermal activity recorded on 4 and 6 June corroborates with VAAC reports from 3-5 June of an ash plume rising to 2.4 km and drifting 45-65 km SW. Numerous thermal anomalies were also recorded by MIROVA during early June.

Even though no more ash plumes were reported until September, thermal anomalies were recorded on 15 June, and 10, 15, and 19 July by MODVOLC, and also show intermittently in the MIROVA data during the late June through September window. September brought more reports of ash plumes on 23-24 and 26-27 and MODVOLC thermal anomalies on days 8, 15, 26 and 28. The ash plumes rose to 1.8 to 2.4 km and drifted 35-100 km N, NE, E, and SE.

While MODVOLC thermal anomalies were only recorded on 14 and 19 October, VAAC ash reports were issued three separate times, over 16-20, 24-26, and 29-30 October. None of the ash plumes rose higher than 2.4 km or drifted farther than 95 km; plumes went in all wind directions during these events. Although there were no more VAAC reports through February 2016, MODVOLC thermal anomalies on 20 November and 6 December 2015, as well as 7 and 23 January 2016 are all consistent with ongoing low level eruptive activity. These data are supported by MIROVA thermal anomalies during this time as well (figure 25).

Figure (see Caption) Figure 25. MIROVA data at Bagana for the period 1 April 2015 to 18 March 2016. Note continued intermittent activity within a few kilometers of the summit during this period. Intervals of increased activity in late May-early June, late September and late October 2015 correspond with VAAC reports and/or MODIS thermal data, confirming ongoing activity. Courtesy of MIROVA.

Geologic Background. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. This massive symmetrical, roughly 1850-m-high cone was largely constructed by an accumulation of viscous andesitic lava flows. The entire edifice could have been constructed in about 300 years at its present rate of lava production. Eruptive activity is frequent and characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides. Satellite thermal measurements indicate a continuous eruption from before February 2000 through at least late August 2014.

Information Contacts: Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: ftp://ftp.bom.gov.au/anon/gen/vaac/); 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://hotspot.higp.hawaii.edu/); MIROVA, 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/).


Kanlaon (Philippines) — April 2016 Citation iconCite this Report

Kanlaon

Philippines

10.412°N, 123.132°E; summit elev. 2435 m

All times are local (unless otherwise noted)


Sporadic ash explosions during November-December 2015 and March 2016

According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), after an ash explosion at Kanlaon on 23 July 2006 and a series of earthquakes the day after (BGVN 32:02), activity subsided. Only non-eruptive activity was reported between the 2006 explosion and 24 November 2015, when ash emission began following strong seismicity and steam explosions the day before; intermittent ash emissions continued through 30 December. Activity resumed briefly with explosions and ash plumes during 29-31 March 2016.

Reports during 2008-2010. During 26 July-2 November 2006, no ash explosions occurred, and both steam emissions and seismicity were low, prompting PHIVOLCS to lower the Alert Level from 1 to 0 (out of 5).

PHIVOLCS reported that during 7-10 February 2008, the seismic network detected a significant rise in earthquakes, prompting them to raise the Alert Level from 0 to 1 on 10 February. Cloud cover prohibited visual observations of the summit. According to a news account (Sun Star News), seismic activity returned to background levels during 5 March-25 April (0-3 earthquakes/day), persuading PHIVOLCS to lower the Alert Level to 0 on 25 April 2008.

During 23 August-1 September 2009 the PHIVOLCS seismic network detected a significant rise in the number of earthquakes. A few of the earthquakes were felt as far away as Bago City, 30 km NW. The epicenters clustered on the NW flank.

Based on a pilot observation, the Tokyo Volcanic Ash Advisory Center (VAAC) reported that on 15 May 2010 an ash plume rose to an altitude of 2.4 km and drifted W. Ash was not identified in satellite imagery. PHIVOLCS later confirmed that the plume originated from a fire and not an eruption. No further reports were issue by PHIVOLCS until November 2015.

Activity during November-December 2015. At 0930 on 23 November 2015 the seismic network detected an explosion-type signal, culminating with an 8-minute-long steam explosion. Observers reported that a white plume rose 1-1.5 km above the crater and drifted SW, and rumbling was heard in local areas. Only four volcanic earthquakes had been recorded during the previous week, but after the explosion, the network detected volcanic tremor that lasted for five hours. The Alert Level was raised to 1. Continuous steam emissions with minor ash content were observed the next morning. During 24-25 November, the seismic network detected 11 volcanic earthquakes; on 25 November, gas-and-ash emissions rose 150 m above the crater and drifted SW.

According to PHIVOLCS, two volcanic earthquakes accompanied by a one-minute, low-energy, gray ash emission occurred at 0513 on 11 December 2015. Observers also noted ash emissions at 0951, 1008, 1140, and 0101 on 13 December that rose 200-300 m and drifted SW. The emissions were not detected by the seismic network, indicating a shallow source. Trace amounts of ashfall were reported in nearby communities on the W and SW flanks. At 2138 on 15 December a low-frequency earthquake lasted 45-47 seconds. Inclement weather prevented visual observations of the crater. Rumbling was heard in neighborhoods on the SE flank. On 17 December white steam plumes rose 50 m above the crater. Poor weather conditions prevented further views of the crater through 22 December.

PHIVOLCS reported that at 1457 on 23 December 2015, the seismic network detected an explosion. The event was not visually observed due to dense weather clouds around the summit area, but rumbling was heard in nearby barangays (villages) including Cabagnaan, La Castellana (16 km SW), and Ara-al and Yubo, La Carlota City (14 km W). Minor amounts of ash fell in Ara-al, Haguimit, and La Granja, La Carlota City, and a sulfur odor was noted in barangay Tres Elis, La Castellana. Another explosive event was detected at 2109 on 24 December, but was again not visually observed. Trace amounts of ash fell in Ara-al, Haguimit, and La Granja, and a sulfur odor was reported in Tres Elis. On 26 December, white steam plumes rose 100 m above the crater and drifted SW. A five-minute long ash event that began at 1329 on 27 December was accompanied by rumbling heard in a few local barangays. An eruption plume, viewed from the SE flank, rose 1 km above the crater, and may have risen as high as 4.5 km based on pilot observations. Minor ashfall was noted in nearby communities as far as 58 km WNW. About 1230 on 30 December, a low-energy explosion produced an ash plume that rose 100 m above the crater and slowly drifted SW.

Activity during March-April 2016. According to PHIVOLCS, at 1820 on 29 March 2016, the seismic network detected a 12-minute explosion that was accompanied by a booming sound heard in nearby communities. Observers to the SE reported an ash plume that rose 1.5 km above the crater, and minor amounts of ash fell in areas downwind. Incandescent ejecta caused a small fire on the upper flank. A 25-second-long explosion was detected at 1918. On 30 March at 0130, a long-duration tremor began that was accompanied by gas-and-steam plumes that rose 600-700 m and drifted SW and SSW. On 31 March 2016, minor ashfall was reported in areas downwind, including in parts of La Carlota City (14 km W), La Castellana, and Bago City in Negros Occidental. The tremor continued during 2-4 April, though the energy decreased, and steam plumes rose 400-500 m. On 5 April steam plumes rose 800 m and drifted SW. The Alert Level remained at 1.

According to a 30 March 2016 news account (The Manila Times), PHIVOLCS said that GPS monitoring had detected slight inflation between December 2015 and 14 March 2016

Geologic Background. Kanlaon volcano (also spelled Canlaon), the most active of the central Philippines, forms the highest point on the island of Negros. The massive 2435-m-high andesitic stratovolcano is dotted with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km to the SW from Kanlaon. The summit of Kanlaon contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller, but higher, historically active vent, Lugud crater, to the south. Historical eruptions from Kanlaon, recorded since 1866, have typically consisted of phreatic explosions of small-to-moderate size that produce minor ashfalls near the volcano.

Information Contacts: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Department of Science and Technology, PHIVOLCS Building, C.P. Garcia Avenue, Univ. of the Philippines Campus, Diliman, Quezon City, Philippines (URL: http://www.phivolcs.dost.gov.ph/); Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Sun Star News (URL: http://www.sunstar.com.ph/); The Manila Times (URL: http://www.manilatimes.net/).

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 Atmospheric Effects


The enormous aerosol cloud from the March-April 1982 eruption of Mexico's El Chichón persisted for years in the stratosphere, and led to the Atmospheric Effects section becoming a regular feature of the Bulletin. Descriptions of the initial dispersal of major eruption clouds remain with the individual eruption reports, but observations of long-term stratospheric aerosol loading will be found in this section.

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 Special Announcements


Special announcements of various kinds and obituaries.

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 Additional Reports


Reports are sometimes published that are not related to a Holocene volcano. These might include observations of a Pleistocene volcano, earthquake swarms, or floating pumice. Reports are also sometimes published in which the source of the activity is unknown or the report is determined to be false. All of these types of additional reports are listed below by subregion and subject.

Turkey


False Report of Sea of Marmara Eruption


Africa (northeastern) and Red Sea


False Report of Somalia Eruption


Africa (eastern)


False Report of Elgon Eruption


Kermadec Islands


Floating Pumice (Kermadec Islands)

1986 Submarine Explosion


Tonga Islands


Floating Pumice (Tonga)


Fiji Islands


Floating Pumice (Fiji)


New Britain


Likuranga


Andaman Islands


False Report of Andaman Islands Eruptions


Sangihe Islands


1968 Northern Celebes Earthquake

Kawio Barat


Mindanao


False Report of Mount Pinokis Eruption


Southeast Asia


Pumice Raft (South China Sea)

Land Subsidence near Ham Rong


Ryukyu Islands and Kyushu


Pumice Rafts (Ryukyu Islands)


Izu, Volcano, and Mariana Islands


Mikura Seamount

Acoustic Signals in 1996 from Unknown Source

Acoustic Signals in 1999-2000 from Unknown Source


Kuril Islands


Possible 1988 Eruption Plume


Mongolia


Har-Togoo


Aleutian Islands


Possible 1986 Eruption Plume


Mexico


False Report of New Volcano


Nicaragua


Apoyo


Colombia


La Lorenza Mud Volcano


Ecuador


Altar


Pacific Ocean (Chilean Islands)


False Report of Submarine Volcanism


Central Chile and Argentina


Estero de Parraguirre


West Indies


Mid-Cayman Spreading Center


Atlantic Ocean (northern)


Northern Reykjanes Ridge


Azores


Azores-Gibraltar Fracture Zone


Antarctica and South Sandwich Islands


Jun Jaegyu

East Scotia Ridge



 Special Announcements


Special Announcement Reports