Thermal alerts indicate possible activity during August-October 2002

Thermal alerts detected by MODIS within the 2001-2002 period occurred only during August-October 2002 (figure 3) in the summit area. The first alert occurred on 13 August 2002 when a single alert-pixel had an alert ratio of -0.542. On 10 October the anomaly consisted of two alert-pixels with a maximum alert ratio of -0.409, and on 21 October the anomaly was characterized by six alert-pixels (clustered SW of the summit) with a maximum alert ratio of -0.571.

Figure 3. MODIS-detected alerts on Arjuno-Welirang during May-December 2002. Thermal alerts collated by Diego Coppola and David Rothery; data courtesy of the Hawaii Institute of Geophysics and Planetology's MODIS Thermal Alert Team.

The Volcanological Survey of Indonesia reported that the volcano was at Status Level I (no activity) in October 2002. No observations were reported, but only distant tectonic earthquakes were detected at the seismograph station.

An explosive eruption took place in the NW part of Gunung Welirang in October 1950, and eruptive activity was reported on the NW flank (Kawah Plupuh) in August 1952. Steam plumes from the summit of Welirang were photographed from space on 13 September 1991 (BGVN 16:08) and in mid-November 1994.

Information Contacts: Dali Ahmad, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Diego Coppola and David A. Rothery, Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, UK. Thermal alerts courtesy of the HIGP MODIS Thermal Alerts Team (URL: http://modis.higp.hawaii.edu/).

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

August 1991 (BGVN 16:08) Cite this Report

White plume from Welirang summit

A plume from the summit area of Welirang . . . was photographed by Space Shuttle astronauts on 13 September at [1535] (photo no. S48-151-064) (figure 1). The dense portion of the apparently ash-poor plume extended roughly 50 km N and more diffuse material continued for another 65 km. The summit area was white and apparently de-vegetated. A plume was observed again on direct video downlink from the spacecraft on [17] September at [1306]. No ground reports were available at press time.

Figure 1. Space Shuttle photograph showing a steam plume from Welirang (just east of the central cloud mass). Also, the lack of vegetation at the peak indicates volcanic activity. Volcanoes on Java form an E-W line of peaks the length of the island; five are in this image. NASA Photo ID: STS048-151-064, 13 September 1991.

Information Contacts: C. Evans and D. Helms, NASA-SSEOP.

November 1994 (NASA STS 66)

Steam plume in mid-November seen from space

A photograph taken from the Space Shuttle in mid-November 1994 showed a possible steam plume originating from the summit of Arjuno (figure 2).

Figure 2. This is a striking, oblique view to the south of the Indonesian islands of Java (right), Bali and Lombok (upper left). The linear array of dark regions across the photo is a chain of volcanoes. Plumes of steam can be seen rising from the summits of Arjuno (eastern Java, near the center of the photo) and Merapi (central Java, near the right of the photo). The region appears hazy due to an extended drought over Indonesia, New Guinea, and Australia resulting in huge fires and a regional smoke pall. NASA Photo ID: STS066-154-157. Approximate date: 14 November 1994.

Information Contacts: NASA JSC Digital Image Collection (URL: http://images.jsc.nasa.gov/).

March 2003 (BGVN 28:03) Cite this Report

Thermal alerts indicate possible activity during August-October 2002

Thermal alerts detected by MODIS within the 2001-2002 period occurred only during August-October 2002 (figure 3) in the summit area. The first alert occurred on 13 August 2002 when a single alert-pixel had an alert ratio of -0.542. On 10 October the anomaly consisted of two alert-pixels with a maximum alert ratio of -0.409, and on 21 October the anomaly was characterized by six alert-pixels (clustered SW of the summit) with a maximum alert ratio of -0.571.

Figure 3. MODIS-detected alerts on Arjuno-Welirang during May-December 2002. Thermal alerts collated by Diego Coppola and David Rothery; data courtesy of the Hawaii Institute of Geophysics and Planetology's MODIS Thermal Alert Team.

The Volcanological Survey of Indonesia reported that the volcano was at Status Level I (no activity) in October 2002. No observations were reported, but only distant tectonic earthquakes were detected at the seismograph station.

An explosive eruption took place in the NW part of Gunung Welirang in October 1950, and eruptive activity was reported on the NW flank (Kawah Plupuh) in August 1952. Steam plumes from the summit of Welirang were photographed from space on 13 September 1991 (BGVN 16:08) and in mid-November 1994.

Information Contacts: Dali Ahmad, Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/); Diego Coppola and David A. Rothery, Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, UK. Thermal alerts courtesy of the HIGP MODIS Thermal Alerts Team (URL: http://modis.higp.hawaii.edu/).