Journal article
Interacting Intraplate Fault Systems in Australia: The 2012 Thorpdale, Victoria, Seismic Sequences
J Attanayake, D Sandiford, LS Schleicher, A Jones, G Gibson, M Sandiford
Journal of Geophysical Research Solid Earth | AMER GEOPHYSICAL UNION | Published : 2019
DOI: 10.1029/2018JB016945
Abstract
Using a new seismic waveform data set, we locate 234 earthquakes and estimate source parameters (focal mechanisms, magnitude, and stress drop) of the two largest earthquakes (E1 and E2) in the 2012 seismic sequence in Thorpdale, Victoria. The focal mechanisms suggest thrust faulting, consistent with previous observations in southeast Australia. The estimated magnitudes are Mw 4.9 ± 0.14 (E1) and 4.3 ± 0.1 (E2). The estimates of stress drop 57 ± 7.4 MPa (E1) and 28 ± 2.4 MPa (E2) reflect strength of faults in an intraplate environment. By analyzing spatiotemporal distribution of aftershocks, we show that E1 and E2 reflect two separate seismic sequences about a month apart. E1 and E2 ruptured ..
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Awarded by Australian National Low Emissions Coal Research and Development
Funding Acknowledgements
The authors wish to acknowledge financial assistance provided through Australian National Low Emissions Coal Research and Development (ANLEC R&D) and the Education Investment Fund (EIF) for the project 7-1115-0284. ANLEC R&D is supported by Australian Coal Association Low Emissions Technology Limited and the Australian Government through the Clean Energy Initiative. Seismic monitoring equipment used in this study is part of AuScope's Australian Geophysical Observing System (AGOS) Subsurface Observatory and is funded through an Education Investment Fund (EIF) Round 3 grant. We acknowledge the many landowners who hosted temporary seismographs during this study and also thank the Seismology Research Centre (SRC) for providing data from private monitoring networks. Seismicity data in Figure 1 are obtained from IRIS Wilber 3. SAC (Goldstein et al., 2003), Taup Toolkit (Crotwell et al., 1999), and GMT5 (Wessel et al., 2013) were used for data processing and visualization. All data except those from the SR network can be accessed from the website (http://meiproc.earthsci.unimelb.edu.au/eqserver/).Access to SR data is restricted but can be obtained by contacting the authors. We also thank an anonymous reviewer, Takuji Yamada, and Editor Martha Savage for their comments that improved this manuscript significantly.