Gede Suantika
Center for Volcanology and Geological Hazard Mitigation (CVGHM)

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Numerical Simulation of Pyroclastic Flow of Karangetang Volcano Based on 2015 Eruption Activity Banggur, Willi FS; Patria, Cahya; Kriswati, Estu; Abdurrachman, Mirzam; Suantika, Gede; Syahbana, Devy Kamil; Korompis, Richard; Adriansyah, David; Gurasali, Aditya; Wenas, Alfred; Praja, Kurnia; Sentosa, Imam; Kusnadi, Iing; Shimomura, Makoto
Journal of Geoscience, Engineering, Environment, and Technology Vol. 9 No. 1 (2024): JGEET Vol 09 No 01 : March (2024)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2024.9.1.14217

Abstract

On May 7-9, 2015 the eruptive activity of Mount Karangetang released pyroclastic flows towards the Batuawang River for 3.6 km and hit Kora kora village which is located south of the Main Crater. This pyroclastic flow originated from lava flows during the effusive eruption period. MODIS satellite image hotspot data shows the lava flow extrusion rate and total volume at the peak began to increase since April 2015 and continued to show an increase until December 2015, with the estimated volume and lava extrusion rate on  April 22, 2015 reaching 4.16x106 m3 and 0.53 m3/s, respectively, and on December 9, 2015 the volume reached 1.67x107 m3 with a lava extrusion rate of 1.97 m3/s. The results of field checks show that this pyroclastic flow is dominated by block and ash, and by using numerical simulations show the deflection of pyroclastic flow in accordance with the flow field of the Batuawang river, and the splash of pyroclastic flow towards Kora kora village in addition to the location adjacent to the river flow and also controlled by the narrowing of the river channel due to the accumulation of material in the flow field. A total of 8 numerical simulation cases have been carried out, and in our opinion with an input volume of 500 x103 m3 and a flow material friction of 0.5 is a case that corresponds to a flow event that reaches a distance of 3.6 km from the Main Crater.  Taking into account the current activity conditions we used the same parameters to estimate the area that could be affected by pyroclastic flows in the future. Numerical simulation show that the pyroclastic flow traveled 5 km in a south-southwest direction from the top of the main crater.
Performance of zero water discharge (ZWD) system with nitrifying bacteria Bacillus megaterium and microalgae Chaetoceros calcitrans components in super intensive pacific white shrimp Litopenaeus vannamei culture at low salinity Rahim, Rahim; Suantika, Gede; Muhammad, Harish
Jurnal Akuakultur Indonesia Vol. 17 No. 2 (2018): Jurnal Akuakultur Indonesia
Publisher : Indonesian Society of Scientific Aquaculture (ISSA)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3542.02 KB) | DOI: 10.19027/jai.17.2.137-146

Abstract

ABSTRACTThis research aimed to obtain the performance of super intensive white shrimp rearing using zero water discharge (ZWD) system. This study consisted of four steps, (1) activation and cultivation of nitrifying bacteria, microalgae C. calcitrans and B. megaterium; (2) acclimatization of Pacific white shrimp PL10 with 30 g/L of salinity and decreasing salinity at 2–3 g/L/day; (3) conditioning of ZWD system; (4) white shrimp rearing in 400 L of tank for ten weeks. The experiment used three treatments, (a) shrimp reared without any addition of microbial agent with water exchange conducted every week as much as10–20% of total rearing volume as control (K); (b) ZWD systems with the applications of nitrifying bacteria, (C. calcitrans and B. megaterium) without water discharge  (P1); and (c) ZWD system with the application of microalgae C. calcitrans and B. megaterum without water discharge (P2). According to the results, application of nitrifying bacteria, microalgae C. calcitrans and B. megaterium were able to improve the performance of ZWD system performance of white shrimp rearing at low salinity. In addition, the ZWD system was also able to increase the growth rate and survival rate of shrimp when it compared to control. The best rearing performance was found in ZWD system with application of microalgae C. calcitrans and B. megaterium. Keywords: Litopenaeus vannamei, ZWD, low salinity, microalgae, nitrification bacteria.   ABSTRAKPenelitian ini bertujuan untuk mengetahui kinerja budidaya udang putih super intensif bersalinitas rendah menggunakan sistem zero water discharge (ZWD).  Penelitian ini terbagi dalam tiga, yaitu (1) aktivasi dan kultur bakteri nitrifikasi, mikroalga C. calcitrans dan B. megaterium; (2) aklimatisasi udang putih PL10 salinitas 30 g/L dan penurunan salinitas 2–3 g/L/hari; (3) pengondisian dari sistem ZWD; (4) pemeliharaan udang putih selama 10 minggu di bak bervolume 400 L. Penelitian ini menggunakan tiga perlakuan ; (a) perlakuan kontrol tanpa penambahan  mikroba dan pergantian air setiap minggu sebanyak 10–20% (K) ; (b) sistem ZWD dengan bakteri nitrifikasi, mikroalga C. calcitrans dan B. megaterium tanpa pergantian air (P1); (c) sistem ZWD dengan  mikroalga C. calcitrans dan B. megaterum tanpa pergantian air (P2). Berdasarkan hasil yang didapat, aplikasi bakteri nitrifikasi, mikroalga C. calcitrans dan B. megaterum mampu meningkatkan kineja sistem ZWD pada budidaya udang putih L. vannamei bersalinitas rendah. Selain itu, aplikasi bakteri nitrifikasi, mikroalga C. calcitrans dan B. megaterum pada sistem ZWD juga mampu meningkatkan laju pertumbuhan dan sintasan udang putih dibanding dengan kontrol. Kinerja pemeliharaan terbaik dijumpai pada sistem ZWD dengan aplikasi mikroalga C. calcitrans dan B. megaterum. Kata kunci: bakteri nitrifikasi, Litopenaeus vannamei, mikroalga, salinitas rendah, ZWD