Authors / CoAuthors
McPherson, A.A. | Clark, D.J.
Abstract
Tectono-geomorphic landscape features in Australia, many of which are neotectonic, can be interpreted in the context of long-term patterns of large earthquake occurrence and used to inform contemporary earthquake hazard science. Such features often represent our only means of defining seismic source parameters such as fault slip-rate, large earthquake recurrence and magnitude. They therefore provide an avenue for extending the short historic catalogue of seismicity to timeframes commensurate with the slow strain accumulation rates characteristic of intraplate environments. In addition to being a key input to seismic hazard assessment, there is a growing realisation that analyses of tectono-geomorphic landscape features might also be used to inform mineral exploration, groundwater resource assessment and agricultural land use planning. The Avonmore Scarp in the Campaspe River valley of north-central Victoria is one such example of a tectono-geomorphic (and neotectonic) landscape feature. The controlling fault displaces Ordovician basement, a Paleogene `deep lead paleovalley (including a valley-fill basalt flow), and overlying sediments. The north-south oriented fault scarp (excluding two en echelon segments to the north-east) has a 35 km long surface expression and a maximum vertical topographic offset of 45 m, preserving evidence of perhaps 23 surface-rupturing earthquakes of around magnitude seven (Mw7.0). Displacement involving bedrock at (or near) the surface at the southern end of the scarp is likely to preserve a larger number of events than in the younger alluvium further north, owing to possible reworking within the valley. The potential for strain sharing with other structures in the region has implications for the spatial and temporal occurrence of large earthquakes in central Victoria, and consequently for seismic hazard. The fault system, particularly the more recently reactivated shallowly west-dipping faults, is spatially associated with ?Paleozoic mineralised structures within basement rocks. Neotectonic deformation is likely to have influenced the physical and chemical dispersion of pathfinder elements and prospective materials. In addition, the Avonmore Scarp and its associated faulting have implications for groundwater resources within the Campaspe River valley. In particular, structural deformation may be influencing the distribution, quality, and thus sustainability of local groundwater systems. The fault-related reorganisation of drainage systems has also exerted controls over the distribution and properties of agricultural soils within the valley.
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nonGeographicDataset
eCat Id
89956
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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- GA Publication
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2016-01-01T00:00:00
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