Smithsonian Institution
Global Volcanism Network Bulletin v. 19, no. 10, October 1994
Merapi (Indonesia)  Pyroclastic flows on 22 November kill at least
      41 people on the SSW flank

central Java, Indonesia (7.54 S, 110.44 E)
All times are local (= GMT + 7 hours)
Collapse of the active summit dome on 22 November produced
pyroclastic block-and-ash flows and glowing surges that traveled
SSW up to 7.5 km from the summit (figure 1). As of 28 November, 41
people had died and another 43 were at hospitals in serious
condition. All of the victims lived in areas near the banks of the
Boyong River. That river flows off Merapi's S flanks and, at ~28 km
map distance from the summit, passes through the city of Yogyakarta
(population ~50,000). The threats to areas on Merapi's S flank were
noted in February 1994, when rockfalls were first observed and
reported along the Boyong River. Every month since March, the
possibility of SW-flank destruction had been mentioned in Berita
Merapi (Merapi News) informing local governments, including Sleman
Regency (where this disaster took place), of hazards posed by nuees
ardentes. Rockfalls from the dome have recently traveled down the
Boyong and other rivers for distances of 500-1,500 m.
The eruption was preceded by low-frequency earthquakes on 20
October. Multiphase seismic events and rockfalls continued to be
recorded at normal levels, with occasional low-frequency events,
but one tremor episode occurred on 3 November. On 4 November this
change in seismic behavior was reported to the Chief of Regencies.
During 21-22 November, a team from the Merapi Volcano Observatory
(MVO) climbed to the summit to observe dome development and to
install an extensometer station to measure the offset along cracks.
The first nuee ardente was recorded instrumentally at 1014 on 22
November, and was observed visually from the Plawangan, Ngepos,
Babadan, and Jrakah observation posts. The team at the summit saw
a vertical plume that originated from a location somewhere on the
S part of the dome.
The intensity of the nuees ardentes increased at 1020, prompting
the observer at Plawangan to send a warning to the forestry officer
at Kaliurang (figure 1), a well-known tourist resort. The officer
then yelled a warning to the local people. Five minutes later
(1025) MVO instructed all observation posts and radio stations of
the Regional Task Force that the alert status had been raised to
the highest level (Level 4), and that evacuations should begin. At
1045 the observer at Plawangan sent a message to the Chief of Pakem
District, but he was already in the field, probably because he had
heard the previous warning. Another evacuation warning was radioed
to regional task forces at 1100. By 1215 the first victim had been
discovered. The Plawangan observation post was abandoned at 1508
and the personnel temporarily moved to Kaliurang. The nuees
ardentes had diminished by 1720 that evening.
A NOAA/NESDIS volcano hazards alert stated that at 1346 on 22
November a plume rose to ~10 km. At that time winds aloft were
toward the W at 18 km/hour. These same points were repeated in an
aviation safety alert ("Notice To Airmen," or NOTAM).
A United Nations Department of Humanitarian Affairs (DHA) report on
23 November stated that 25 of 40 employees building a water
treatment facility were still missing, while 15 were found dead.
Evacuees totalled 6,026 from the neighboring villages in the
subdistrict of Pakem. Evacuation and emergency response measures
had been undertaken by the local authorities and community members.
The DHA reported that local volcanology officials advised
authorities and local people to remain on alert for 7 days.
A 23 November Tokyo Kyodo broadcast (in English) reported
"Indonesia's team for disaster safety in Yogjakarta said ash rain
has reached Temanggung, about 45 km NW of Merapi."  A UPI news
report stated that, on the morning of 23 November, an official of
the natural disasters office in Sleman said that 118 people were in
three hospitals suffering from serious burns. The report further
stated that "hundreds of homes have collapsed and thousands of
cattle were buried by ash."  On 26 November UPI reported that
>4,700 people remained in evacuation centers.
According to press accounts and other information collected by the
U.S. Embassy and issued on 23 and 25 November, most of the
casualties occurred when superheated gases swept through two small
villages (Desa Purwobinangun and Desa Hargobinangun in the Sleman
district). The eruption ignited ~500 hectares of rainforest near
Kaliurang, which press reports said had been damaged by ashfall.
Embassy reports on 25 November stated that an estimated 34-200
people were still missing (there had been no communication with
some affected villages on the slopes of the volcano). Well over 500
injured persons had been treated at local hospitals. The 25
November Embassy report said that "Local authorities are now
concerned about an accumulation of volcanic material [on Merapi's
flanks]. It is feared that the approaching rainy season could
dislodge this material (estimated in the range of 11 million m^3)
causing dangerous [mudflows] in the villages below. City officials
in Yogyakarta . . . are reported to be constructing a third
catchment dam to regulate volcanic material entering the Code
river, which runs through the city."
A 23 November Reuters press report stated that "The official Antara
news agency said that despite warnings, local people were reluctant
to leave the area, regarding the volcano as sacred and likely to
offer some supernatural signs if it were to cause a major
Merapi is one of the most active volcanoes in Indonesia. The
stratovolcano has an exposed, summit lava dome, the source of
abundant glowing blocks that continue to tumble down its S-SW
slopes, a region settled by at least 50,000 people. In historical
time, instability of the growing dome has led to nuees ardentes
that have caused many fatalities, disasters described in many
popular books on volcanology.
Information Contacts: Sukhyar, MVO, Volcanological Survey of
Indonesia, Jalan Diponegoro No. 57, Bandung, Indonesia; Synoptic
Analysis Branch, NOAA/NESDIS, Camp Springs, Maryland, USA; DHA
Disaster Administrator, Geneva, Switzerland; Associated Press;
Reuters News Services, United Press International; Antara News
Correction:  The last report on Merapi (Bulletin v. 19, no. 8)
discussed seismic data. Unfortunately, the reported low-frequency
signal was later found to be caused by instrumental problems not
recognized at the time of submission.
Figure 1. Deposits of the Merapi eruption of 22 November 1994 shown
on a 500-m-contour base map of the SW quadrant with the primary
drainages and some towns labeled. Courtesy of Sukhyar, MVO.