Report on Ebulobo (Indonesia) — November 2013
Bulletin of the Global Volcanism Network, vol. 38, no. 11 (November 2013)
Managing Editor: Richard Wunderman.
Ebulobo (Indonesia) August 2013–glowing areas and hot plumes
Please cite this report as:
Global Volcanism Program, 2013. Report on Ebulobo (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 38:11. Smithsonian Institution.
8.817°S, 121.191°E; summit elev. 2096 m
All times are local (unless otherwise noted)
Our last report (CSLP 19-69) discussed a summit eruption at Ebulobo stratovolcano, near the S coast of Central Flores island, that in 1969 had emitted ash and steam as well as "fire" (generally taken as incandescence but also possibly flames). CVGHM (Center for Volcanology and Mitigation of Geologic Disasters), issued a report on Ebulobo on 26 August 2013 informing readers that during August 2013, observers noted one or more hot emissions escaping from the crater. The resulting plume was of sparse consistency, white in color, under weak pressure, and it rose to 5-30 m above the peak. "Smoke" was noted.
The CVGHM report noted that on the night of 21 August 2013, observers on the volcano's N side saw incandescence at the summit area. Observations during the night of 22-23 August revealed points of glowing remained unchanged. The glowing was considered anomalous, having not been seen since 2011. The exact cause of the incandescent regions was not reported No new fissures, lava flows or pyroclastic flows were reported. The glowing later terminated as discussed in an October follow up report.
During June 2013, the system recorded the earthquakes shown in table 1.
Table 1. A summary of seismicity recorded at Ebulobo. Dashes signify cases without reported data. Extracted from the 26 August and 17 October CVGHM reports.
|Month (2013)||Shallow (VB)||Deep volcanic (VA)||Low-frequency (long period)||Local tectonic (TL)||Long distance (TJ)|
During 1-22 August 2013, the seismic system also recorded tremor with maximum amplitudes in the range of 0.5-15 mm.
Ebulobo (figure 1) has a dedicated observation post and two seismic instruments as discussed further below.
Glow diminishes and Alert Level drops (to I). During September-October white plumes rose as high as 100 m above the crater. Despite that, the glowing area had remained absent after 27 August. On 17 October CVGHM scaled back the Alert from II to I (Normal, on a scale that reaches IV).
More background. The following was extracted from CVGHM reporting.
"Ebulobo Volcano is located in the district of Nagekeo, province of Nusa Tenggara Timur. Eruptions of Ebulobo generally have consisted of lava streams that quickly formed mounds but have never so far resulted in sudden eruptive outbursts that produced a symmetrically shaped mass to the volcano. Ebulobo's eruptions have occurred between 3 and 58 years. In its historical record, its latest eruptive activity took place in 1941 and consisted of a lava stream.
"Observation of Ebulobo's activity is carried out from its monitoring post in the village of Ekowolo, sub-district of Boa Wae and is done visually and according to tremor events. The monitoring is done by means of a Type VR-60 seismograph and a Type L4C seismometer. The readings are transmitted by a telemetric system."
Geologic Background. Ebulobo, also referred to as Amburombu or Keo Peak, is a steep-sided symmetrical stratovolcano in central Flores Island. The Watu Keli lava flow traveled down the N flank to 4 km from the summit in 1830, the first of only four recorded historical eruptions of the volcano.
Information Contacts: Center for Volcanology and Mitigation of Geologic Disasters (CVGHM), Jalan Diponegoro 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); and theNational Agency for Disaster Management (BNPB), Gedung Graha 55 Jl. Tanah Abang II No. 57 Postal Code: 10120, Jakarta Pusat, Indonesia (URL: http://www.bnpb.go.id/).