TY  - JOUR
A1  - Muksin, Umar
A1  - Haberland, Christian
A1  - Nukman, Mochamad
A1  - Bauer, Klaus
A1  - Weber, Michael H.
T1  - Detailed fault structure of the Tarutung Pull-Apart Basin in Sumatra, Indonesia, derived from local earthquake data
JF  - Journal of Asian earth sciences
N2  - The Tarutung Basin is located at a right step-over in the northern central segment of the dextral strike-slip Sumatran Fault System (SFS). Details of the fault structure along the Tarutung Basin are derived from the relocations of seismicity as well as from focal mechanism and structural geology. The seismicity distribution derived by a 3D inversion for hypocenter relocation is clustered according to a fault-like seismicity distribution. The seismicity is relocated with a double-difference technique (HYPODD) involving the waveform cross-correlations. We used 46,904 and 3191 arrival differences obtained from catalogue data and cross-correlation analysis, respectively. Focal mechanisms of events were analyzed by applying a grid search method (HASH code). Although there is no significant shift of the hypocenters (10.8 m in average) and centroids (167 m in average), the application of the double difference relocation sharpens the earthquake distribution. The earthquake lineation reflects the fault system, the extensional duplex fault system, and the negative flower structure within the Tarutung Basin. The focal mechanisms of events at the edge of the basin are dominantly of strike-slip type representing the dextral strike-slip Sumatran Fault System. The almost north south striking normal fault events along extensional zones beneath the basin correlate with the maximum principal stress direction which is the direction of the Indo-Australian plate motion. The extensional zones form an en-echelon pattern indicated by the presence of strike-slip faults striking NE SW to NW SE events. The detailed characteristics of the fault system derived from the seismological study are also corroborated by structural geology at the surface. (C) 2014 Elsevier Ltd. All rights reserved.
KW  - Focal mechanism
KW  - Seismicity
KW  - Structural geology
KW  - Extensional duplex
KW  - Flower structure
KW  - Sumatran fault
KW  - Pull-Apart Basin
Y1  - 2014
U6  - https://doi.org/10.1016/j.jseaes.2014.09.009
SN  - 1367-9120
SN  - 1878-5786
VL  - 96
SP  - 123
EP  - 131
PB  - Elsevier
CY  - Oxford
ER  -