Kelud volcano is considered as one of the most dangerous volcanoes of ... Small
lateral parasitic vents are also present on the flanks of the volcano; they have.
Kelud volcano The Kelud (or Kelut) is a relatively small stratovolcano with a summit elevation at 1731m above sea level or 1650m above the densely populated and fertile plains of Kediri and Blitar that surround the volcano. Kelud volcano is located at about 27 km from the city of Kediri (population: 1,300,000) and lies between the volcanic massif of Gunung Wilis to the West and the complex of Kawi and Butak volcanoes to the East. Kelud volcano is considered as one of the most dangerous volcanoes of Java because of its frequent eruptions. The eruptive activity has typically generated deadly lahars, pyroclastic flows and surges that have claimed more than 15,000 lives since 1500 AD and caused widespread fatalities and destruction. The crater lake of Kelud is famous for its potential to release devastating lahars whenever an eruption occurs. The 1586 eruption produced one of the worst lahar in the historical record of volcanic eruptions and took the lives of about 10,000 people. Extensive works to control lahars have been achieved around the volcano. A system of drainage of the crater lake was completed in 1926. Today, this drainage tunnel still works and maintains the volume of the lake at a low level (2 million m3). Several dams were also built on the slopes of this volcano in order to protect the largest towns.
Figure 2.1 Map of eastern Java. Kelud is on the west side of the N-S alignment of Welirang-Arjuna and Kawi-Butak volcanoes.
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Geological Setting Gunung Kelud is a composite stratovolcano built by the accumulation of numerous lava flows (eastern and northeastern flanks) pyroclastic flows, pyroclastic surges and lahar deposits from the youngest activity of the volcano. Debris-avalanche deposits, several hundred meters thick underlie these deposits, and were produced by slope failures of the western side of the volcano (Thouret et al., 1998). Several andesitic lava domes (Sumbing, Gajah Mungkur) are present in the sommital area, some present spectacular columnar joint structure. Small lateral parasitic vents are also present on the flanks of the volcano; they have erupted mostly lava flows. The most recent eruption (1990) produced medium-K basaltic andesite pumice and scoria with plagioclase, orthopyroxene, clinopyroxene and magnetite as phenocrysts (Bourdier et al., 1997). Their composition (Table 2.1) is comparable to magmas produced by the eruptive activity during the last centuries. Eruptive activity More than 30 eruptions have been recorded in historical times. Kelud’s 1000 AD eruption is the oldest in the historical record of eruptions for the entire Indonesian archipelago. Since AD 1300, the periods of inactivity between eruptions range from 9 to 75 years (Kusumadinata, 1979, Thouret al. 1998). During the past century, eruptions occurred in 1901, 1919, 1951, 1966 and 1990. All these recent eruptions were very similar and were characterized by a very short duration (a few hours) and a low volume of eruptive products (0.1-0.2km3) with VEI = 3-4. Explosive activity typically started with a phreatomagmatic outburst followed by a short plinian eruption with convective columns reaching altitude of more than 10 km. These eruptions produced devastating lahars, pyroclastic surges and flows as well as ashfall deposits (see figures 2.2 and 2.3).
Figure 2.2 dispersion of ashfall deposits from the 1901 and 1919 eruptions of Kelud volcano. Adapted from Kemmerling (1921). During the 1919 eruption, the volcanic ash was distributed in two lobes. The low altitude ash cloud was dispersed eastward and extended as far as Bali and the high altitude cloud dispersed to the West.
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Table 2.1: Composition of the Kelud eruption products.
SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 L. I.
1 55.19 0.58 18.2 7.51 0.17 3.85 8.86 2.42 0.57 0.08 1.73
2 56.15 0.57 18.28 6.46 0.16 3.43 8.48 2.39 0.59 0.07 2.7
3 56.06 0.58 18.48 8.23 0.2 3.94 9.15 3.3 0.53 0.08 0.16
4 55.24 0.62 18.7 8.71 0.2 3.5 9.09 3.11 0.83 0.08
5 55.05 0.62 18.5 8.84 0.21 3.74 9.2 3.05 0.79 0.26
Total
99.15
99.28
100.71
100
100
