Sangeang Api

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  • 8.2°S
  • 119.07°E

  • 1949 m
    6393 ft

  • 264050
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18 June-24 June 2014

PVMBG reported seismic and visual monitoring of Sangeang Api during 1-17 June. During clear conditions, incandescence at the summit and white-and-gray plumes (100-1,500 m above the summit) were visible. On 1 June seismicity dramatically decreased, and as of 17 June was still declining. The Alert Level was reduced from 3 to 2 (on a scale of 1-4) on 17 June.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Index of Weekly Reports


2014: May | June
2013: May | June
2012: October | December
2009: June

Weekly Reports


18 June-24 June 2014

PVMBG reported seismic and visual monitoring of Sangeang Api during 1-17 June. During clear conditions, incandescence at the summit and white-and-gray plumes (100-1,500 m above the summit) were visible. On 1 June seismicity dramatically decreased, and as of 17 June was still declining. The Alert Level was reduced from 3 to 2 (on a scale of 1-4) on 17 June.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


11 June-17 June 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 14 June an ash plume from Sangeang Api rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 55 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


4 June-10 June 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 4-7 June ash plumes from Sangeang Api rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 45-110 km W and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


28 May-3 June 2014

PVMBG reported that during January-29 May diffuse white plumes rose at most 25 m above Sangeang Api's crater. On 30 May seismicity increased, with tremor starting at 0500 and becoming continuous at 1348. An eruption at 1555 generated an ash plume that rose 3 km and drifted W, causing ashfall over the sea. The Alert Level was raised to 3 (on a scale of 1-4). The island has no permanent settlements, and is only occupied during the growing and harvest seasons; civil authorities evacuated 135 people to the mainland. Based on satellite images, pilot observations, and the Indonesian Meteorological Office, the Darwin VAAC reported that on 30 May an ash plume rose to an altitude of 15.2 km (50,000 ft) a.s.l. and drifted 440 km E and 750 km SE.

BNPB reported that on 31 May two larger explosions occurred at 1330 and 2242. According to the VAAC, ash plumes from those explosions rose to altitudes of 13.7-15.2 km (45,000-50,000 ft) a.s.l. and drifted 280 km NW and other various directions. Later in the day the ash plumes became detached. Ashfall affected many areas in the Bima Regency on the mainland, including Wera, and prompted the evacuation of 7,328 people from four villages within a radius of 8 km from Sangeang Api. The Bima and Tambolaka airports were temporarily closed. According to a news article, all flights to and from the Darwin International Airport in Australia on 31 May were canceled.

The VAAC noted that ash plumes rose to an altitude of 4.3 km (14,000 ft) a.s.l. on 1 June and drifted W and SW. During 2-3 June ash plumes rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l. and drifted 45 km W.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM); Badan Nacional Penanggulangan Bencana (BNPB); Darwin Volcanic Ash Advisory Centre (VAAC); The Guardian News


12 June-18 June 2013

CVGHM reported that during May through 13 June diffuse white plumes rose 10 m above Sangeang Api's crater. Both the lava dome and surrounding areas showed no changes since November 2012. The Alert Level had been increased to 3 (on a scale of 1-4) on 19 May due to a trend of increasing seismicity; as many as 77 shallow earthquakes and 66 deep earthquakes had been detected daily. Residents and tourists were advised to stay away from the craters within a radius of 5 km. Since then seismicity decreased; 15 shallow earthquakes and three deep earthquakes were recorded on 13 June. The Alert Level was lowered to 2 on 14 June. The public were advised not to approach the craters within a radius of 1.5 km.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


15 May-21 May 2013

CVGHM reported that during 1-19 May diffuse white plumes rose 10 m above Sangeang Api's crater. Both the lava dome and surrounding areas showed no changes since November 2012. Seismicity had increased on 26 April and remained high. The Alert Level was raised to 3 (on a scale of 1-4) on 19 May. Residents and tourists were advised not to approach the craters within a radius of 5 km.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


26 December-1 January 2013

CVGHM reported that during November through mid-December observers at the Sangeang, Bima observation post (50 km SW) noted occasional diffuse white plumes rising 5-15 m above Sangeang Api's crater. The lava dome and surrounding areas had not changed compared to October observations. Avalanches had occurred on the W and SW flanks. Earthquakes had declined. The Alert Level was lowered to 2 (on a scale of 1-4) on 21 December.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


10 October-16 October 2012

CVGHM reported that during 1-10 October Sangeang Api was often not visible due to fog; occasionally plumes were visible and rose as high as 20 m above the crater. The lava dome and surrounding areas had not changed compared to the beginning of the year. Both the number and magnitude of earthquakes increased on 5 October, declined during 6-8 October, then again increased on 9 October. The Alert Level was raised to 3 (on a scale of 1-4) on 10 October.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


3 June-9 June 2009

CVGHM reported that on 4 June the Alert Level for Sangeang Api was raised to 2 (on a scale of 1-4) due to recent increases in the number of earthquakes. White plumes rose 5-25 m during 1 May-3 June.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)


Index of Monthly Reports

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.

07/1985 (SEAN 10:07) Explosions eject tephra, lava flow; island evacuated

08/1985 (SEAN 10:08) Eruption declines; 4.5 km lava flow

09/1985 (SEAN 10:09) 30 July eruption plume seen on satellite images

10/1985 (SEAN 10:10) Lava advance stops; fewer and smaller explosions

11/1985 (SEAN 10:11) Strombolian explosions; lava flow in growing channel; pyroclastic flow deposit

12/1985 (SEAN 10:12) Summit explosions in July and December

01/1986 (SEAN 11:01) Continued gas explosions and lava ejection

03/1986 (SEAN 11:03) Small explosions increase slightly

04/1986 (SEAN 11:04) Continued small explosions; glow

05/1986 (SEAN 11:05) Explosions and lava flow advance continue

06/1986 (SEAN 11:06) Explosions and crater glow continue

07/1986 (SEAN 11:07) Ash clouds; red glow above crater

09/1986 (SEAN 11:09) Fewer explosions

10/1986 (SEAN 11:10) Explosions continue

11/1986 (SEAN 11:11) Numerous explosions

12/1986 (SEAN 11:12) Small explosions but no seismicity

02/1987 (SEAN 12:02) Frequent small gas explosions

03/1987 (SEAN 12:03) Small gas explosions continue

04/1987 (SEAN 12:04) About 50 small explosions daily

06/1987 (SEAN 12:06) Frequent explosions continue

07/1987 (SEAN 12:07) Activity continues; plumes to 600 m

08/1987 (SEAN 12:08) Small explosions continue

09/1987 (SEAN 12:09) Small explosions continue

10/1987 (SEAN 12:10) Fewer explosions

12/1987 (SEAN 12:12) Eruptive activity continues at steady rate

02/1988 (SEAN 13:02) Explosions and earthquakes end

05/1999 (BGVN 24:05) March to May plumes are thin and rise to 150 m above the summit

07/2009 (BGVN 34:07) Increased seismicity, including explosion earthquakes, during May-June 2009

12/2009 (BGVN 34:12) Explosive eruptions during 1997-1999 were previously unreported

07/2013 (BGVN 38:07) Fumarolic emissions and variable seismicity during 2012-2013

02/2014 (BGVN 39:02) Ashfall from 30 May 2014 eruption causes evacuations, airline delays


Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

All times are local (= UTC + 8 hours)

07/1985 (SEAN 10:07) Explosions eject tephra, lava flow; island evacuated

"Sangeang Api . . . began to erupt on 30 July, with a series of explosions from the summit crater (Doro Api). The first explosion occured at about 0900 and produced a plume of tephra and gas to about 3,500 m altitude. Additional explosions occurred at 1130 (6,500 m), 1320 (6,500 m), and 1800 (1,500 m). Ashfall in Bima (50 km SW of the volcano), the capital of Sumbawa, totaled about 2 mm, and ashfall along the NE coast of Sumbawa, in the vicinity of the village of Wera, totaled about 2 cm. Between 30 July and 1 August, the 1,242 inhabitants of Sangeang Api island were evacuated to Sumbawa. Numerous additional Vulcanian explosions took place during the following week, reaching a maximum altitude of 2,500 m. Poor weather prevented systematic observations 1-5 August. On 6 August at 1939, a 0.7-km-long aa flow was observed advancing W from the region of Doro Api crater, toward the village of Doro Sangeang. By 9 August, the flow was 1.7 km long.

"The most recent eruption of Sangeang Api was in 1966; earlier eruptions occurred in 1512, 1715, 1821, 1860, 1911, 1912, 1927, 1953, [1954-1958 (six eruptions)], and 1964. Typical activity begins with strong Vulcanian explosions followed within a few days by Strombolian explosions. Eruptions in 1953 and 1964 ended with a lava flow and weak Strombolian explosions. Lavas from Sangeang Api are of basaltic composition (49-51% SiO2)."

Information Contacts: VSI.

08/1985 (SEAN 10:08) Eruption declines; 4.5 km lava flow

"Sangeang Api continued to erupt in early September. Activity consisted of a single lava flow that has moved approximately 4.5 km W from Doro Api. The frequency of explosions has declined steadily from ~150/day in early August to ~50/day in early September. The maximum explosion cloud height was ~1 km. From 9 to 14 August, the number of small (M < 1) shallow volcanic earthquakes ranged from 190-400/day. By 6-11 September the number of volcanic earthquakes had decreased to 12-40/day."

"A gas plume has been continuously emitted from the volcano since activity began on 30 July. In late August, the gas plume rose less than 0.5 km and was carried W by steady winds. The plume was translucent with a bluish gray to bluish white color. The larger explosions contributed dark gray clouds of fine tephra to the plume. Its SO2 content was in the range of 50-100 metric tons/hour when measured on 23 August."

"The evacuation of the approximately 1,250 inhabitants from Sangeang Island was completed in early August. Inhabitants are in the process of moving their homes to Sumbawa Island."

Information Contacts: J. Matahelumual and T. Casadevall, VSI.

09/1985 (SEAN 10:09) 30 July eruption plume seen on satellite images

GMS images showed plumes from the initial 30 July activity (figure 1). Digital data analyses of temperatures at the tops of the plumes compared with radiosonde altitude profiles suggested that they reached a maximum altitude of 14.1 km (table 1), below the tropopause. However, Yosihiro Sawada notes that for both this and other eruptions, altitudes calculated with this technique seem to be consistently higher than estimates from ground observers.

Figure 1. Surface temperatures (in °C) of eruption clouds from Sangeang Api (left), 30 July 1985, 1400 (top) and 1700 (bottom) Zones of plume surface from Sangeang Api (right) with temperatures <10°C on 30 July at 1400, 1700, 1830, and 2000. The volcano is indicated by a solid triangle. Courtesy of Yosihiro Sawada.

Table 1. Sangeang Api eruption cloud data from GMS satellite images on 30 July, 1985. Maximum altitude of the eruption cloud is estimated by comparing the GMS digital temperature data with temperature/altitude data profiles from nearby radiosondes. No plume was evident on the image returned at 1100. A plume could be detected from 30 July at 1400 until 31 July at 0200, but none was visible 3 hours later. Maximum plume extent was reached at 1900.

    Time  Length  Width  Min      Max    Remarks
	   (km)    (km)  Temp   Alt (km)

    1400   135     105   -71°C    14.1   emerging from volcano
    1700   315     100   -50°C    11.8   detached from volcano
    1800   385     150   -37°C    10.2   detached from volcano
    1830   405     160   -30°C     9.4   detached from volcano
    1900   425     130   -24°C     8.5   detached from volcano

Information Contacts: Y. Sawada, MRI, Tsukuba.

10/1985 (SEAN 10:10) Lava advance stops; fewer and smaller explosions

"Sangeang Api entered into eruption on 30 July. The main features of the activity included an initial phase of mild Vulcanian explosions, followed by Strombolian explosions, a lava flow, and a persistent plume of water vapor and gas. The initial explosions on 30 July were accompanied by a small nuée ardente that followed the drainage of the Sori Kawangge 4 km down the SSW flank to ~200 m altitude, and produced a dark-colored, hornblende-bearing pumice. The eruption has continued through the first week of November but at a greatly reduced level from August. The frequency of explosions has declined steadily from ~150/day in early August to ~50/day in early September and fewer than 6/day in early November. The maximum height of the explosion cloud was ~1 km above the vent in August and <300 m above the vent by early November.

". . . The daily earthquake count shows a steadily decreasing trend, and in early November the number of earthquakes was <30/day. The lava flow, first observed on 6 August flowing W from the region of Doro Api crater (toward the village of Doro Sangeang), had advanced to about 4.7 km from the summit by 1 October. The flow showed no additional growth during October."

Photographs taken by astronauts from Space Shuttle mission 61A (30 October-5 November) showed a fairly dense plume extending roughly 50-100 km from Sangeang Api (figure 2).

Figure 2. Space Shuttle photograph (no. 61A-40-062), taken 5 November 1985, showing a plume emerging from Sangeang Api, plus a portion of Sumbawa Island. Note that north is to the left. Courtesy of Charles A. Wood.

Information Contacts: J. Matahelumual, Suparto S., and T. Casadevall, VSI; C. Wood, NASA.

11/1985 (SEAN 10:11) Strombolian explosions; lava flow in growing channel; pyroclastic flow deposit

"Sangeang Api continued to erupt with 10-30 Strombolian explosions/day in November and the first week in December. The 1985 lava channel had not lengthened from the 4.7 km observed in late September. However, the volume of the main channel has grown because of a considerable increase in height during the past 2 months. A slow-moving lava flow in the central channel is located atop the main feeder tube. Periodic overflows of this channel add both fluid lava and rubble to the outer flanks of this tube. On 5 December, four separate overflows of fluid lava and rock rubble were observed rolling down the sides of the central channel.

"A brief visit was made to the central crater on 4 December during a period of quiet. The active vent was a large cinder cone in Doro Api Crater. This central cone, which previously rose about 40 m from the floor of Doro Api, was estimated to be approximately 180-200 m above the floor during the 4 December visit. Thundering detonations were heard almost continuously during the 15 minutes spent in the crater and 1 mild Strombolian explosion hurled incandescent blocks. At night, a continuous reddish glow at the bottom of the gas plume over the crater suggested that a small lava lake may exist within Doro Api or the central cone. Fountaining of fluid lava, sheets, or ribbons was observed to accompany some of the larger Strombolian explosions at night.

"We also confirmed the existence of a small-volume pyroclastic flow that was probably produced during the initial activity of 30 July. Local residents reported that the activity caused a number of small fires in the vicinity of Doro Montoy crater (just N of Doro Api) and the Sori Mbere drainage on the S flank of the volcano. A small block and ash flow, still hot to the touch, was found in the Sori Mbere drainage in December. Lahars generated by heavy rainfall and unconsolidated material on the upper slopes of the volcano have been common during and immediately after previous episodes. Outcrops along the shoreline indicate that a number of lahars and possibly also pyroclastic flows have entered the sea. Small mudflows were produced by heavy rains on 2 December. One travelled down the Sori Mbere drainage while a second mudflow entered the sea at Oi Nono Jara on the S side of Sangeang Island.

"This pattern of activity conforms to that of previous 20th century eruptions of Sangeang Api. The 1911 activity included numerous explosions and a lava flow from the summit crater that moved more than 6 km down the W flank. The activity that began in March 1953 produced a lava flow and intermittent explosions through 1954. The 1964 eruption began on 29 January with strong explosions from the 1954 crater, and a lava flow first observed on 3-4 February moved N and E to about 750 m elevation. Explosions and outflow of lava continued for at least several months and possibly until the end of 1965."

Information Contacts: T. Casadevall and L. Pardyanto, VSI.

12/1985 (SEAN 10:12) Summit explosions in July and December

"Sangeang Api continued to erupt in December. Compositions of 30 July pumice and mid-August dense lava bombs are given in table 2."

Table 2. Whole rock analyses of samples collected from Sangeang Api. X-ray fluorescence analyses by the USGS Laboratory, Denver, Colorado. Sample 1: pumice from eruption on 30 July 1985. Sample 2: ejected block, dense lava explosion mid-August 1985. Total iron expressed as Fe203; loss on ignition at 900°C.

    Element    No. 1    No. 2
	
    SiO2       53.8     49.3
    Al2O3      18.9     17.9
    Fe2O3       7.23    11.1
    MgO         2.51     4.60
    CaO         7.30    10.2
    Na20        4.33     3.07
    K20         3.60     2.40
    TiO2       [0.66]    1.03
    P2O5        0.38     0.32
    MnO         0.22     0.23
    LOI         1.09     0.05
    Total    [100.02]  100.2

Information Contacts: Suparto S. and T. Casadevall, VSI.

01/1986 (SEAN 11:01) Continued gas explosions and lava ejection

"Activity started on 30 July [1985] from the main summit crater (Doro Api . . .). At about 0900 a thick plume rose to 3,500 m height. The eruption continued with explosions at 1130 (6,500 m), 1320 (6,500 m) and 1800 (1,500 m). About 2 mm of ash fell in Bima, 50 km SW of the volcano. Between then and 5 August explosions occurred every 30-60 minutes. Black plumes reached 2,000-2,500 m height. On 6 August at 1939 lava was observed flowing W from Doro Api crater. At the end of September the lava flow had advanced ~4,750 m. Numerous explosions took place from September to November, producing columns ~400-500 m high. On 17 November an explosion ejected incandescent lava fragments to ~250 m height and a plume rose to 1,200 m above the crater [see also 10:7-12]. During December and January, gas explosions, sometimes accompanied by ejection of incandescent lava fragments, averaged ~80 events/day. The 1,242 inhabitants of the island were evacuated to the main island of Sumbawa. There were no casualties."

Information Contacts: A. Sudradjat, VSI.

03/1986 (SEAN 11:03) Small explosions increase slightly

". . . By comparison with activity in December and January, the frequency of small explosions increased slightly during February and March to ~80/day [but see 11:1]. The height of the eruption clouds averaged ~900 m. Since December 1985, no visits have been made to examine the 1985 lava flow, but continued lava production is suspected."

Information Contacts: Olas, A. Sudradjat, and T. Casadevall, VSI.

04/1986 (SEAN 11:04) Continued small explosions; glow

". . . Activity consisted of small explosions with eruption clouds reaching <1 km above the crater. Persistent glow has been observed above the summit crater during the night, suggesting the presence of lava within the crater and in the 1985 lava channel which drains W from the crater."

Information Contacts: Olas, Suratman, Suparto, Kaswanda, and A. Sudradjat, VSI.

05/1986 (SEAN 11:05) Explosions and lava flow advance continue

Observers at Sangeang Api reported no changes in the eruption . . . . Several explosions/hour at Doro Api crater and slow growth of the lava flow continued. Only rockfall earthquakes were recorded.

Information Contacts: A. Sudradjat, L. Pardyanto, and T. Casadevall, VSI.

06/1986 (SEAN 11:06) Explosions and crater glow continue

The eruption continued through June with several explosions/day that produced clouds reaching ~1 km above the summit. A persistent reddish glow continued to be visible at night above Doro Api crater.

Information Contacts: L. Pardyanto, Olas, Kaswanda, A. Sudradjat, and T. Casadevall, VSI.

07/1986 (SEAN 11:07) Ash clouds; red glow above crater

Sangeang Api has been in continuous eruption for a year. Activity in July included several explosions/day, producing eruption clouds . . . ~1 km above the summit. A persistent reddish glow was visible at night above the Doro Api crater.

Information Contacts: L. Pardyanto, Olas, Kaswanda, Suratman, A. Sudradjat, and T. Casadevall, VSI.

09/1986 (SEAN 11:09) Fewer explosions

"Explosions from the summit crater decreased in frequency during September."

Information Contacts: L. Pardyanto, Olas, Kaswanda, Suratman, A. Sudradjat, and T. Casadevall, VSI.

10/1986 (SEAN 11:10) Explosions continue

Summit explosions . . . were continuing in October.

Information Contacts: Suratman and T. Casadevall, VSI.

11/1986 (SEAN 11:11) Numerous explosions

During November >130 explosions were recorded from Dori Api crater. The maximum height of eruption columns was 700 m. Continued extrusion of lava was suspected but not confirmed. No volcanic earthquakes were recorded.

Information Contacts: VSI; ANS.

12/1986 (SEAN 11:12) Small explosions but no seismicity

Explosions continued from Doro Api Crater, ranging from 40 to 70/day from December through the first week in January. Maximum plume height was 800 m. No volcanic earthquakes were recorded.

Information Contacts: VSI.

02/1987 (SEAN 12:02) Frequent small gas explosions

About 60 small gas explosions/day continued to occur through February. Plumes reached maximum heights of 600 m. No volcanic seismicity was recorded.

Information Contacts: VSI.

03/1987 (SEAN 12:03) Small gas explosions continue

March eruptive activity consisted of ~250 small gas explosions with plumes reaching a maximum height of 600 m above the crater rim. Of the 22 earthquakes recorded during March, 17 were of tectonic origin (deep) and five were volcanic (shallow).

Information Contacts: VSI; T. Casadevall, USGS & VSI.

04/1987 (SEAN 12:04) About 50 small explosions daily

Sangeang Api continued in eruption with an average of ~50 small explosions/day during April. The maximum plume height was 600 m. No earthquakes were detected during April.

Information Contacts: T. Casadevall, USGS & VSI.

06/1987 (SEAN 12:06) Frequent explosions continue

Eruptive activity continued during May and June with ~50 explosions/day . . . . Plumes reached ~600 m above the crater rim. No earthquakes accompanied the explosions.

Information Contacts: VSI.

07/1987 (SEAN 12:07) Activity continues; plumes to 600 m

Eruptive activity continued during July with ~45 explosions/day producing plumes to 600 m above the crater rim. No earthquakes accompanied the explosions. No VSI geologist has been able to visit the island to inspect the activity since early 1986.

Information Contacts: VSI.

08/1987 (SEAN 12:08) Small explosions continue

The eruption . . . continued in August, with ~25 explosions/day ejecting plumes to ~600 m above the crater rim. A seismometer 5 km from the summit recorded no earthquakes accompanying the explosions.

Information Contacts: VSI.

09/1987 (SEAN 12:09) Small explosions continue

September activity was similar to . . . August, with ~25 explosions/day. Plumes reached ~600 m above the crater rim.

Information Contacts: VSI.

10/1987 (SEAN 12:10) Fewer explosions

Eruptive activity continued in October at a rate of ~18 explosions/day, with plumes reaching ~600 m above the crater rim. The number of daily explosions has declined steadily from 50-70/day in early 1987, and the October rate is the lowest since the eruption started in July 1985.

Information Contacts: VSI.

12/1987 (SEAN 12:12) Eruptive activity continues at steady rate

Eruptive activity continued during November and December at ~18 explosions/day, about the same rate as in October.

Information Contacts: VSI.

02/1988 (SEAN 13:02) Explosions and earthquakes end

The number of explosions . . . declined steadily from 50-70/day in early 1987 to ~15/day at the end of the year. By February, explosions had stopped, although fuming continued from the summit crater, producing a whitish plume. No earthquakes were reported during February.

Information Contacts: VSI.

05/1999 (BGVN 24:05) March to May plumes are thin and rise to 150 m above the summit

As of 21 February the seismograph was under repair so the volcano was monitored visually. During 9 March-24 May a "white ash plume" rose 10-150 m above the summit. During 27 April - 3 May the plume remained thin, but after 4 May it vacillated between thick and thin.

Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large volcanic cones, 1,949-m-high Doro Api and 1,795-m-high Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent historical eruptions have been recorded since 1512, most of them during in the 20th century.

Information Contacts: Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).

07/2009 (BGVN 34:07) Increased seismicity, including explosion earthquakes, during May-June 2009

According to the Center of Volcanology and Geological Hazard Mitigation (CVGHM), restlessness began at Sangeang Api in May and June 2009. In early May 2009 white emissions reached heights of ~ 5-25 m. In addition, occasional explosion earthquakes and generally minor seismicity continued (table 3). In addition, an earthquake struck on 1-2 June 2009 that was felt at a Modified Mercali intensity of MM I.

Table 3. Summary of reported volcanic activity at Sangeang Api. Courtesy of the Center of Volcanology and Geological Hazard Mitigation (CVGHM).

    Date               Explosions      Tremor and          Deep volcanic    Shallow volcanic
                                       amplitude           earthquakes      earthquakes

    01-17 May 2009     Avg. ~ 3/day    continuous, 3 mm    Avg. ~ 2/day     ~ 1/day
    18-31 May 2009     ~ 13/day        continuous,7 mm     ~ 4/day          ~ 2/day
    01-02 June 2009    ~ 21/day        continuous, 5 mm    ~ 2/day          1/day
    03 June 2009       11              continuous, 6 mm    7                --

On 4 June the Alert Level was raised to 2 (on a scale of 1-4) due to the increases in the number of explosion earthquakes, tremor, and other local earthquakes. Residents and visitors were prohibited from climbing the volcano. No thermal anomalies have been seen in MODIS imagery between 1999 and August 2009.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://portal.vsi.esdm.go.id/joomla/).

12/2009 (BGVN 34:12) Explosive eruptions during 1997-1999 were previously unreported

A recent translation of an older report from the Center of Volcanology and Geological Hazard Mitigation (CVGHM) discussed previously undocumented interval of eruptions at Sangeang Api (figure 3) during 1997-1999. These eruptions were described, along with other known eruptions, in broad terms in their report. They were generally explosive, with lava domes and lava discharges, similar to the eruptions of 1911, 1953, 1954, 1985-1988.

Figure 3. A photograph of the 13-km-wide Sangeang Api taken on 15 October 2002 by Space Shuttle astronauts (photo STS-112-E-5628). A wide channel running W from provides a path for inferred lava and pyroclastic flows. Courtesy of NASA Earth Observatory.

Dali Ahmad confirmed the occurrence of explosive activity during the 1997-1999 period. These took place without causing casualties because, since 1989, all of the island residents had departed to the nearby Sumbawa Island. No additional eruptions were indicated through at least 2009. In recent times the island's summit crater has produced intermittent steam clouds.

Turner and others (2003) used Uranium-series isotopes to provide insights into Sangeang Api magma evolution. The volcano erupts potassic lavas (SiO2 ~47–55%) with a spectrum of xenoliths that record the liquid line of descent. The scientists estimated that the Sangeang Api magma chamber was about 6-10 km3 in volume and underwent cooling rates of ~0.05°C/year.

Reference. Turner, S., Foden, J., George, R., Evans, P., Varne, R., Elburg, M., and Jenner, G., 2003, Rates and processes of potassic magma evolution beneath Sangeang Api volcano, East Sunda Arc, Indonesia: Journal of Petrology, v. 44, no. 3, pp. 491-515.

Information Contacts: Dali Ahmad, Center of Volcanology and Geological Hazard Mitigation (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (Email: dali@vsi.esdm.go.id, URL: http://www.vsi.esdm.go.id/); NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/).

07/2013 (BGVN 38:07) Fumarolic emissions and variable seismicity during 2012-2013

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02/2014 (BGVN 39:02) Ashfall from 30 May 2014 eruption causes evacuations, airline delays

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Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-tranchyandesitic volcanic cones, 1949-m-high Doro Api and 1795-m-high Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent historical eruptions have been recorded since 1512, most of them during in the 20th century.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2014 May 30 2014 Jun 9 ± 8 days Confirmed 3 Historical Observations Summit crater
[ 2009 May 1 ] [ 2009 Jun 3 ] Uncertain    
1997 1999 Confirmed 2 Historical Observations
1985 Jul 30 1988 Feb Confirmed 3 Historical Observations Doro Api
1966 Feb 28 1966 Nov Confirmed 2 Historical Observations
1964 Jan 29 1965 Dec 1 ± 30 days Confirmed 2 Historical Observations Doro Api
1958 Unknown Confirmed 1 Historical Observations
1957 Unknown Confirmed 1 Historical Observations
1956 Dec Unknown Confirmed 1 Historical Observations
1955 Unknown Confirmed 1 Historical Observations
1954 Nov 4 Unknown Confirmed 2 Historical Observations
1954 Apr 26 Unknown Confirmed 2 Historical Observations
1953 Mar 19 1953 May 15 (in or after) Confirmed 3 Historical Observations Doro Api
1927 Unknown Confirmed 2 Historical Observations
1912 Apr Unknown Confirmed 2 Historical Observations
1911 Feb 13 1911 Mar 2 Confirmed 2 Historical Observations Doro Api
1860 Sep 11 1860 Oct Confirmed 2 Historical Observations
1821 Mar 23 Unknown Confirmed 2 Historical Observations
1715 Unknown Confirmed 2 Historical Observations
1512 Unknown Confirmed 3 Historical Observations

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.



Synonyms
Sangean Api | Gunungapi Bima


Cones
Feature Name Feature Type Elevation Latitude Longitude
Doro Api
    Kalubu Crater
Cone 1949 m
Doro Mantai
    Doro Mantoi
Cone 1795 m
Sangeang Api is a small volcanic island off the NE coast of Sumbawa Island. Two large volcanic cones, Doro Api in the center and Doro Mantoi on the right, were constructed within and on the south rim of a largely obscured caldera. Intermittent eruptions have been recorded since 1512, but the volcano has been frequently active in the 20th century.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey).
An eruption column rises above Doro Api peak of Sangeang Api volcano on August 25, 1985. The eruption, which began on July 30 and lasted until February 1988, included explosive activity, pyroclastic flows, and a lava flow that traveled 4-5 km down the western flank.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey).
A lava flow descends the west flank of Doro Api at Sangeang Api volcano on December 4, 1985. The eruption began on July 30; pyroclastic flows forced the evacuation of the island's 1242 inhabitants. The lava flow eventually traveled 4-5 km before stopping in June 1986. Explosive activity continued until February 1988.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey).
Islanders prepare to evacuate on August 25, 1985, as Sangeang Api volcano erupts in the background. The eruption began on July 30, and included pyroclastic flows that eventually forced the evacuation of the island's entire 1242 inhabitants.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey).
An eruption of Doro Api at Sangeang Api volcano is observed from the village of Doro Mewanga on September 18, 1964. The eruption began on January 29, 1964 and lasted until the end of 1965. During the eruption strong explosions took place from the summit crater and a lava flow traveled down to 750 elevation.

Photo courtesy of Volcanological Survey of Indonesia, 1964.
A column of "smoke" rises in 1985 above Doro Api, one of the two large post-caldera cones of Sangeang Api volcano. Doro Mantoi appears at the right in this view from Sori Buntu on the southern flank. An eruption that included both explosive activity and the effusion of lava flows down the western flank began in July 1985 and lasted until February 1988.

Photo by Samud W., 1990 (Volcanological Survey of Indonesia).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Kusumadinata K, 1979. Data Dasar Gunungapi Indonesia. Bandung: Volc Surv Indonesia, 820 p.

Neumann van Padang M, 1951. Indonesia. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 1: 1-271.

Turner S, Foden J, George R, Evans P, Varne R, Elburg M, Jenner G, 2003. Rates and processes of potassic magma evolution beneath Sangeang Api volcano, East Sunda Arc, Indonesia. J Petr, 44: 491-515.

Varne R, Foden J D, 1986. Geochemical and isotopic systematics of eastern Sunda arc volcanics; implications for mantle sources and mantle mixing processes. In: F-C Wezel (ed), {The Origin of Arcs}, Amsterdam: Elsevier, 159-189.

Volcano Types

Complex
Stratovolcano

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Trachybasalt / Tephrite Basanite
Trachyandesite / Basaltic trachy-andesite
Basalt / Picro-Basalt

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
204
1,155
39,301
809,132

Affiliated Databases

Large Eruptions of Sangeang Api Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.