A study on crustal shear wave splitting in the western part of the Banda arc-continent collision
- Graduate Research on Earthquake and Active Tectonics-ITB, Jl. Ganesha 10, Bandung 40132 (Indonesia)
- Research Centre for Geotechnology -LIPI, Jl. Sangkuriang (Kompleks LIPI) Bandung 40135 (Indonesia)
- Faculty of Mining and Petroleum Engineering ITB, Jalan Ganesha 10, Bandung 40132 (Indonesia)
- Research Centre for Physics - Indonesian Institute of Sciences (LIPI), Puspiptek Serpong 15314,Indonesia (Indonesia)
We analyzed shear wave splitting parameters from local shallow (< 30 km) earthquakes recorded at six seismic stations in the western part of the Banda arc-continent collision. We determined fast polarization and delay time for 195 event-stations pairs calculated from good signal-to-noise ratio waveforms. We observed that there is evidence for shear wave splitting at all stations with dominant fast polarization directions oriented about NE-SW, which are parallel to the collision direction of the Australian plate. However, minor fast polarization directions are oriented around NW-SE being perpendicular to the strike of Timor through. Furthermore, the changes in fast azimuths with the earthquake-station back azimuth suggest that the crustal anisotropy in the study area is not uniform. Splitting delay times are within the range of 0.05 s to 0.8 s, with a mean value of 0.29±0.18 s. Major seismic stations exhibit a weak tendency increasing of delay times with increasing hypocentral distance suggesting the main anisotropy contribution of the shallow crust. In addition, these variations in fast azimuths and delay times indicate that the crustal anisotropy in this region might not only be caused by extensive dilatancy anisotropy (EDA), but also by heterogeneity shallow structure such as the presence of foliations in the rock fabric and the fracture zones associated with active faults.
- OSTI ID:
- 22590888
- Journal Information:
- AIP Conference Proceedings, Vol. 1719, Issue 1; Conference: 4. international conference on theoretical and applied physics (ICTAP) 2014, Bali (Indonesia), 16-17 Oct 2014; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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