Mapping Dangerous Zone of Galunggung Volcanic Mountain Using ArcGIS

Introduction Location 7°15′0″S 108°3′0″E Brief Information/history Mount Galunggung, is an active stratovolcano in West Java, Indonesia, part of the Sunda Arc Extending through Sumatra, Java, and Bali, which has resulted from the subduction of the Indian oceanic plate and the Australian plate beneath the Eurasian Plate.

The last major eruption on Galunggung was in 1982, which had a Volcanic Explosivity Index of 4 and killed 68 peoples. This eruption also brought the dangers of volcanic ash to aviation worldwide attention. It was reported, some airplanes were affected by the volcanic ash and cause the emergency landings.

Eruption photo of Galunggung in 1982

Mapping Dangerous Zone of Galunggung Mountain Ideas Recent eruption happened on Merapi Volcano Mountain has impacted to other volcano mountains. It was reported, the volcanic activities around several mountains were increased soon after the Merapi’s erruption happened. Galunggung Mountain was noted to have increasing volcanic activities related with Merapi’s erruption. Eventhough government already anticipate the recent situation, apparently they don’t provided with any adequate data such as “Dangerous zoning” map of Mount Galunggung. It is important to note, in the volcanic disaster management, the adequate data is one requirement to make right decision. To help “decision maker” doing their job, we create the dangerous zoning map of Galunggung Mountain.

Data and Tools Requirements 1. Geographical Map of Galunggung 2. GIS Software (I use ArcMap and ArcCatalog version 9) 3. Computer. Concepts 1. Mapping dangerous zone is based on lava movement 2. Lava is considered as the liquid phase like the water that flow through the earth surface (hill, and valey) and then gather at the catchment area. 3. Thus, we made the map based on the slope of the mountain, run-off, catchment area, the distance from the main crater

Procedure of Works Load the contour map

Create TIN layer

From TIN we create the Slope Map

Create Catchment Map using ArcHydro tools

Created Weighted Flow Accumulation by using ArcHydro tools

Reclassify the Slope layer

Reclassify the elevation layer

Convert Raster to Features, Slope

Convert Elevation layer to feature

Convert catchment into feature

Convert weighted flow accumulation to feature

Add the zoning layer

Using Union tools to combine all the feature layers

Using dissolve tools, we get result of zoning map based on value that existed on every area