stable continental region
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This investigation uses high-resolution optical satellite imagery to quantify vertical surface offsets associated with the intraplate 20 May 2016 Mw 6.0 Petermann Ranges earthquake, Northern Territory, Australia. The ~20 km long NW-trending rupture resulted from reverse motion on a northeast-dipping fault. We measure vertical surface offsets by differencing pre- and post-earthquake digital elevation models (DEMs) derived from in-track stereo Worldview images. This analysis resolves a maximum vertical deformation of 0.8 ? 0.2 m. We validate these results via comparison to field-based observations and interferometric synthetic aperture radar (InSAR). This new method may be particularly useful for remote characterization of earthquake ruptures with larger (>1 m) vertical deformation, where near-rupture InSAR observations are often compromised by decorrelation.
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<p>The mechanisms that lead to the localisation of stable continental region (SCR) seismicity, and strain more generally, remain poorly understood. Recent work has emphasised correlations between the historical record of earthquake epicentres and lateral changes in the thickness, composition and/or viscosity (thermal state) of the lithospheric mantle, as inferred from seismic velocity/attenuation constraints. Fluid flow and the distribution of heat production within the crust have also been cited as controls on the location of contemporary seismicity. The plate margin-centric hypothesis that the loading rate of crustal faults can been understood in terms of the strain rate of the underlying lithospheric mantle has been challenged in that a space-geodetic strain signal is yet to be measured in many SCRs. Alternatives involving the release of elastic energy from a pre-stressed lithosphere have been proposed. <p>The Australian SCR crust preserves a rich but largely unexplored record of seismogenic crustal deformation spanning a time period much greater than that provided by the historical record of seismicity. Variations in the distribution, cumulative displacement, and recurrence characteristics of neotectonic faults provide important constraint for models of strain localisation mechanisms within SCR crust, with global application. This paper presents two endmember case studies that illustrate the variation in deformation characteristics encountered within Australian SCR crust, and which demonstrate the range and nature of the constraint that might be imposed on models describing crustal deformation and seismic hazard.