VOLCANIC ASH TRANSPORT SIMULATION AND DAMAGE ESTIMATION ON CROPS DUE TO VOLCANIC ERUPTION: CASE STUDY OF SINABUNG VOLCANO

• Main Author: YUDHISTIKA NIM: 12314057, ANDRE
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25544
• Institution: Institut Teknologi Bandung

<p align="justify">The Sinabung Volcano has been erupting since 2010 until now. The eruptions have paralyzed the agricultural sector, which is the most important sector in the Karo Regency, North Sumatra Province. Ironically, the majority of the people are farmers, thus, the Sinabung eruption affects directly both, the financial and the social sectors in the region. Quantitative damage estimation caused by Sinabung eruption is needed and damage needs to be analyzed in order to know how powerful its eruption affects the economy. A volcanic ash transport simulator called FALL3D is used to produce an ash isopach map. The inputs for the simulator are coordinates of the modelling area, TGSD (Total Grain Size Distribution), wind data, ESP (Eruption Source Parameter), aggregation factor, terminal velocity, and diffusion coefficient. The TGSD from Soufriere Hills September 26th 1997 eruption is used due to the incompleteness of Sinabung eruption TGSD on February 19th 2018. The approach is used because their eruption style is similar. The wind data is taken from ERA-Interim reanalysis, which is accessible trough internet. The ESP must also be determined, especially the duration of the eruption, column height, and MFR (Mass Flow Rate) of the erupted materials. The duration of the eruption is adapted from BNPB (Indonesian National Board for Disaster Management) publication and the column height is obtained from satellite observation. The simulation result is displayed as contours of ash thickness in the vicinity of the volcano. The result of FALL3D depicts that the ash isopach of eruption on February 19th 2018 ranges from 1-25 mm. the ash extends to NW and affects six districts: Munte, Kuta Buluh, Payung, Tiganderket, Simpang Empat, and Namanteran. The ash isopachs of 1 mm reaches ~20 km from the vent, and the total area affected is ~233 km2. The simulation result is overlaid with maps of rice fields and crops which are downloaded from BIG (Indonesian Geospatial Information Agency). The data such as productivity of crops per hectare and commodity’s price are obtained from BPS (Indonesian Statistical Agency) of each affected district. Therefore, the damage on crops and rice field is estimated to approximately 18 billion IDR.<p align="justify">