TITLE:
Understanding of Earthquake Damage Pattern through Geomorphological Approach: A Case Study of 2006 Earthquake in Bantul, Yogyakarta, Indonesia
AUTHORS:
Dwi Wahyuni Nurwihastuti, Junun Sartohadi, Djati Mardiatno, Udo Nehren, Restu
KEYWORDS:
Earthquake Damage Pattern, Geomorphology, Subsurface Characteristic
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.2 No.3B,
September
18,
2014
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 geo-morphological 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.