Abstract
An examination of regionally extensive hill-shaded Shuttle Radar Topography Mission (SRTM) 90 m resolution and Department of Land Information (DLI) 10 m resolution digital elevation data, and discussions with government and industry geologists familiar with the local geology, has resulted in the identification of 38 previously unrecognized linear topographic scarps in the southwest and central west of Western Australia. I contend that most of these relate to Quaternary surface-rupturing earthquakes. If validated, this more than doubles the number of Quaternary fault scarps known from this area, bringing the total to 60. The newly recognized scarps average between 25 and 50 km in length and from ∼1.5 to 20 m in height. The geometric, recurrence and spatial attributes of these features make it possible to propose a model describing the causative seismicity. The model contends that uniform contractional strain in the ductile lithosphere manifests as localized, transient and recurrent brittle deformation in zones of pre-existing crustal weakness in the upper lithosphere. The data presented allow for ready calculation of the maximum probable magnitude earthquake for the southwest of Western Australia, and identify ‘earthquake-prone’ regions of interest to seismic hazard assessors.
Published Version
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