Igan Supriatman Sutawidjaja
Center for Volcanology and Geological Hazard Mitigation, Jalan Diponegoro 57, Bandung

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Characterization of volcanic deposits and geoarchaeological studies from the 1815 eruption of Tambora volcano Sutawidjaja, Igan Supriatman; Sigurdsson, Haraldur; Abrams, Lewis
Indonesian Journal on Geoscience Vol 1, No 1 (2006)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (319.283 KB) | DOI: 10.17014/ijog.v1i1.8

Abstract

http://dx.doi.org/10.17014/ijog.vol1no1.20066aThe eruption of Tambora volcano on the island of Sumbawa in 1815 is generally considered as the largest and the most violent volcanic event in recorded history. The cataclysmic eruption occurred on 11 April 1815 was initiated by Plinian eruption type on 5 April and killed more than 90,000 people on Sumbawa and nearby Lombok. The type plinian eruptions occurred twice and ejected gray pumice and ash, to form stratified deposits as thick as 40-150 cm on the slopes and mostly distributed over the district west of the volcano. Following this, at about 7 pm, on 11 April the first pyroclastic surge was generated and progressively became greater extending to almost whole direction, mainly to the north, west, and south districts from the eruption center. The deadliest volcanic eruption buried ancient villages by pyroclastic surge and flow deposits in almost intact state, thus preserving important archaeological evidence for the period. High preservation in relatively stable conditions and known date of the eruptions provide approximate dating for the archaeological remains. Archaeological excavations on the site uncovered a variety of remains were relieved by ground penetrating radar (GPR) to map structural remains of the ancient villages under the pyroclastic surge and flow deposits. These traverses showed that GPR could define structures as deep as 10 m (velocity 0.090 m/ns) and could accurately map the thickness of the stratified volcanic deposits in the Tambora village area.    
Pertumbuhan Gunung Api Anak Krakatau setelah letusan katastrofi s 1883 SUTAWIDJAJA, IGAN SUPRIATMAN
Indonesian Journal on Geoscience Vol 1, No 3 (2006)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (857.567 KB) | DOI: 10.17014/ijog.v1i3.16

Abstract

http://dx.doi.org/10.17014/ijog.vol1no3.20063Since its appearance in 1929, Anak Krakatau Volcano has been growing fastly. The elevation of Anak Krakatau Volcano from 1930 to 2005, within 75 years, has reached 315 m high. The growth rate is approximated to be four meters per year in average. Based on calculation, the volume of the body from the sea fl oor since 1927 until 1981 was 2.35 km3, and then in 1983 was 2.87 km3 and then in 1990 it reached 3.25 km3. The latest volume measurement in 2000, was 5.52 km3. Between 1992 up to 2001, within nine years, the eruption of Anak Krakatau took place almost every day, and it had caused its elevation to increase more than 100 m, and its area extent to become 378,527 m2. If the increase in height and the increase in volume are consistent, it is expected that in 2020, the volume of Anak Krakatau’s edifi ce will proceed the volume of Rakata Volcano, Danan Volcano, and Perbuwatan Volcano (11.01 km3) shortly before catastrophic eruption in 1883. Since this volcano appeared above the sea level, the succession of vegetation never came up to a climax, except some of the species, such as Saccharum sp. and Casuarina sp. those are growing faster after the eruption stopped. The growth of coral reef on the lava fl ows that entered the sea about ten years ago, was much slower than those which are growing around the Rakata, Panjang and Sertung Islands. This case is probably due to the slow rate of cooling process of the lava fl ows, although the lava surfaces are blocky.  
Hydrothermal system of the Papandayan Volcano, West Java, Indonesia and its geochemistry evolution of thermal water after the November 2002 eruption Mazot, Agnes; Bernard, Alain; Sutawidjaja, Igan Supriatman
Indonesian Journal on Geoscience Vol 2, No 1 (2007)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1346.064 KB) | DOI: 10.17014/ijog.v2i1.25

Abstract

http://dx.doi.org/10.17014/ijog.vol2no1.20072Papandayan is a strato volcano situated in West Java, Indonesia. After the last magmatic eruptionin 1772, only few phreatic explosions have been occurring. At the present time, the activity is centeredin the northeast crater manifested by the presence of fumaroles and hot springs. In November 2002an explosive eruption occurred and ejected ash and altered rocks. Study of the altered rocks revealedthat an advanced argillic alteration took place in the hydrothermal system by an interaction betweenacid fl uids and rocks. Four zones of alteration have been formed as a limited extension along faults oracross permeable structures at different levels beneath the active crater of the volcano.Two types of acid fl uids are distinguished in the crater of the Papandayan Volcano: (1) acidsulphate-chloride water with pH values between 1.6 and 4.6, and (2) acid sulphate water with pHvalues between 1.2 and 2.5. The samples collected after the eruption revealed an increase in the SO4/Cl and Mg / Cl ratios. This evolution is likely explained by an increase in the neutralization of acidfl uids which tends to show that water-rock interactions were more signifi cant after the eruption. Thechanges in chemistry observed in 2003 were the consequence of the opening of new fractures whereunaltered or less altered volcanic rocks were in contact with the ascending acid water. The high δ34Svalues (9-17‰) observed in the acid sulphate-chloride water before the November 2002 eruptionsuggest that dissolved sulphates were mainly formed by the disproportionation of magmatic SO2. Onthe other hand, the low δ34S values (-0.3-7 ‰) observed in acid sulphate-chloride water sampled afterthe eruption suggest that the origin of dissolved sulphates for these waters is the surfi cial oxidation ofhydrogen sulphide.
Multi-geohazards of Ende city area Sutawidjaja, Igan Supriatman; Sugalang, Sugalang
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2564.059 KB) | DOI: 10.17014/ijog.v2i4.40

Abstract

http://dx.doi.org/10.17014/ijog.vol2no4.20073The Ende City is a steep mountainous area, of which the height of their peaks are above 1500 m asl. It has the limited extent of plain places, without coastal plains. Due to this condition, large parts of the area are vulnerable to mass-movements mainly debris flows, rock-falls and shallow translational and rotational landslides. On the other hand, Flores Island is a segment of the Banda Arc that contains eleven very active volcanoes and numerous inactive volcanic cones. Two of them, Mount Iya and Mount Kelimutu are included to Ende Regency. The northern foot of Mount Iya is only about 1 km away from the southern outskirts of Ende city. But the presence of Mount Meja and Mount Roja as the barrier, and the orientation of the active crater (K2), the highly explosive eruption of Iya Volcano may not directly endanger the city of Ende. Most pyroclastic flows of previous eruptions and other eruptive material emplaced into the sea, but due to a short horizontal distance between Mount Iya and Ende City, the ejected rock fragments can endanger the city of Ende especially its southern parts. A crack has developed around the active crater (K2) of Iya Volcano. It seems that the crack indicates a major weakness within the volcano, which could result in a giant landslide, entering the sea in future eruptions of Iya Volcano. The kinetic energy which is transmitted through the water may probably generate a tsunami. The Ende City also experienced significant damages in the 1992 earthquake. Luckily this city is located on a solid rock instead of alluvial sediments which can potentially undergo liquefaction. Â