Understanding the Earthquake Threat to Bandung from the Lembang Fault
Eko Yulianto, Indonesian Institute of Sciences (LIPI)
Eko Yulianto, Indonesian Institute of Sciences (LIPI)
Improving the accuracy of earthquake risk assessments for the city of
Bandung and surrounding population centers will allow more accurate
mapping of disaster prone areas to support the development of
appropriate contingency measures. For this purpose, understanding the
threat is a necessity. An earthquake geology study of the Lembang Fault
has been conducted to identify the geological signatures of large
earthquakes that have occurred in the past. Analyses of geomorphology,
stratigraphy and sedimentology, resistivity have been applied to reveal
the geology and paleoseismology of the Lembang Fault. Results of this
study show that the Lembang Fault is a transpressional fault, consists
of two segments separated by a ~200 m transpression zone.
Within the
last 2000 years, this fault has been capable of producing two big
earthquakes of 4 earthquakes those were recorded in sagpond deposit. The
first earthquake of 6.77±0.12 moment magnitude and the second
earthquake of 6.61±0.09 moment magnitude occurred respectively at ca.
2000 yr BP and ca. 500 yr BP and implies a recurrence interval of ca.
1500 years. Those earthquake might have ruptured the Lembang Fault as a
whole.
