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Merapi volcano, Java, Indonesia
volcano number: 0603-25= (according to Volcanoes of the World, 1994 edition)
summit elevation: 2911 m
location: 7.542°S, 110.442°E
Merapi, one of the most active and most dangerous volcanoes on Earth, entered a new eruptive cycle on 20 January 1992, with the extrusion of viscous lava onto the top of a lava dome emplaced between 1984 and 1990. The new dome soon filled much of a breach formed by repeated lava dome collapse since 1961 on the upper SW flank and began spreading more towards the SSW flank, unaffected by eruptions since more than 30 years.
Growth of the new dome occurred in several pulses, each of which culminated in the production of numerous glowing avalanches (pyroclastic flows or nuées ardentes). A particularly vigorous pulse of dome growth occurred in November 1994, leading to rapid destabilization of the dome's oversteepened SSW face and subsequent collapse. The largest pyroclastic flows in many years rushed down the Boyong, Krasak and Bebeng valleys, causing devastation in the Kaliurang recreational area and killing at least 64 people.
This event was the most devastating eruption at Merapi since the death of more than 60 people in 1954 when pyroclastic flows ravaged the NNW and NW flanks of the volcano, a sector only rarely affected by Merapi eruptions during history.
Following the November 1994 disaster, Merapi remained active, sending numerous pyroclastic flows down the SSW flank as the dome continued to grow, and a tongue of viscous lava slowly moved downslope. The most recent report of this activity is of December 1995 when the number of pyroclastic flows falling from the lava flow front temporarily increased. In March 1996, the volcano was described as "very quiet", with low seismicity and no significant surface activity.
According to news agencies and newspaper reports, Merapi became active again on 11 August 1996. Initial reports spoke of "lava" moving towards the Bebeng, Krasak and Boyong valleys. Residents were ordered to prepare for possible evacuation. The mentioning of "lava" is probably erroneous, it is more likely that the volcano has entered a new period of accelerated dome growth causing numerous pyroclastic flows, similar to the activity characteristic of the volcano during its history.
A new episode of highly increased activity occurred in late October-early November 1996. Vigorous dome growth was accompanied by numerous pyroclastic flows into valleys on the southern and southwestern flanks, prompting evacuation of hundreds of villagers from threatened areas. The renewed activity has been the subject of numerous articles in the on-line Kompas newspaper. For those capable of reading Indonesian, this source offers reports on the Merapi activity of 25 October 1996, 26 October 1996, 1 November 1996, 2 November 1996, 3 November 1996, and 4 November 1996. A report in English will surely appear in one of the future issues of the Bulletin of the Global Volcanism Network.
This impressive view shows successive pyroclastic flows rushing down the south flank of Merapi on 22 November 1994. At least 64 people died in these glowing avalanches that affected a sector of the volcano spared from these phenomena since decades. The southeastern (right hand) flank of the volcano can be seen still fully green (=undamaged vegetation) almost up to the summit, giving testimony to the sharp boundaries of the areas affected by pyroclastic flows. Photo was widely published in the German press the day after (23 Nov 1994), courtesy of Reuters. Click on image to get large (110 kb) version.
Nice shot of Merapi in eruption on 3 November 1996. Incandescent rockfalls from the growing lava dome are leaving yellow-orange streaks on the southwestern flank of the volcano. The lights of the outskirts of Yogyakarta are in the foreground. Photo was published in the German newspaper "Hannoversche Allgemeine" on 5 November 1996, courtesy of Reuters. Click on image to get large (35 kb) version.
Reports in various issues of the GVN Bulletin