Mapping Dangerous Zone of Galung-gung Volcanic Mountain Using ArcGIS

Introduction

• Location7°15′0″S 108°3′0″E

• Brief Information/historyMount Galunggung, is an active stratovol-cano 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 Galung-gung was in 1982, which had a Vol-canic 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

• IdeasRecent 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 vol-canic activities related with Merapi’s erruption. Eventhough government already anticipate the recent situation, appar-ently 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 manage-ment, the adequate data is one requirement to make right decision. To help “decision maker” doing their job, we cre-ate the dangerous zoning map of Galunggung Mountain.

• Data and Tools Requirements1. Geographical Map of Galunggung2. GIS Software (I use ArcMap and ArcCatalog version 9)3. Computer.

• Concepts1. Mapping dangerous zone is based on lava movement2. 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