| Abstrak/Abstract |
The last major earthquake in Bantul causing severe damage occurred on May 27th, 2006. The damages in the flat area of Bantul had a certain pattern. The damages pattern controlled the subsurface characteristic below the flat area. Understanding earthquake damage pattern through geomorphological approach is important for earthquake hazard analysis. The techniques of remote
sensing and Geographical Information Systems were applied to analyze earthquake damage pattern and geomorphological characteristics. Gravity analysis was used to identify the subsurface
structure and the basement depth while geoelectric analysis was used to identify sediment depth.
Moreover, spatial correlation analysis was used to identify the relationship between the earthquake damage, geomorphological characteristics, and subsurface characteristics. The results
show that fluvial, marine, and aeolian landforms have low rock density value based on gravity
analysis. These indicate that they were composed by thick unconsolidated material of quaternary
alluvium. While denudational, structural, and solutional landforms composed by material of tertiary rocks have high rock density value. The severe damage occurred in the area that has a lower
value of local gravity and deeper basement. In contrast, the slight damage occurred in the area
that has higher values of local gravity and shallower basement. Moreover, the severe damage occurred in areas of thicker sediment that consist of unconsolidated material. Consequently, the
area of unconsolidated material that has deeper basement and thicker sediment is prone to
earthquake. They were located on fluvial, marine, and aeolian landforms.
|
