A few weeks ago, Nadine Reitman (USGS) published an interesting paper about the use of Photogrammetry for Paleoseismic Trenching in BSSA. In this guest blog she shares her key findings and explains how to minimise errors without spending too much time measuring control points. Thanks Nadine!
Structure-from-motion (SfM) is now routinely used to construct orthophotos and high-resolution, 3D topographic models of geologic field sites. Here, we turn SfM on its side and use it to construct photomosaics and 3D models of paleoseismic trench exposures. Our results include a workflow for the semi-automated creation of seamless, high resolution photomosaics designed for rapid implementation in a field setting and a new error analysis of SfM models. more
The Canyonlands National Park, Utah, is famous for its beautiful landscape and spectacular landforms. For many geoscientists it is also well-known as a sandstone reservoir analogue and as a tourist you’ll often run into groups of geologists on field trips. It’s a matter of debate how and how fast the beautiful grabens in the Needles Fault zone formed – these are large arcuate canyons several tens of kilometres in length, paralleling the Colorado River. In a new paper we present results from remote sensing, mapping, and georadar (GPR). Our aim was to better understand the coupling between deformation, erosion and deposition in such an active system. Based on our findings we developed a model of graben formation and describe the geometry of the dilatant faults at depth. We argue that either the grabens are older than previously assumed or that sedimentation rates were much higher in the Pleistocene.
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The Sparta Fault in Greece is marked by one of the most impressive mountain fronts I’ve ever seen. A huge (yes, huge!) fault scarp has developed, traceable for kilometers; the fault itself is more than 60 km long. Ancient Sparta has been devastated by the last known major (M>7) earthquake that happened at this fault in 464 BC. Now, Papanikolaou et al. have published new data on this fault. They examined how paramaters like throw, segmentation, and catchments vary along strike and created a new seismic hazard map, showing a site-specific long-term recurrence interval of ~1.8 ka (+/- 450 a). more
In Evelyn’s one-picture-per-day-to-save-some-time-before-Christmas-series, my contribution today is from the Canyonlands, Utah. It’s a view to the north from Needles Outpost campsite, directly at the boarder of the National Park. The reddish sandstones give a beautiful contrast to the dark-blue sky. The picture was taken during the night, there were always that incredible view and millions of stars. No comparison to light-polluted Germany! The tents, which have been our home for three weeks, were completely messed with the ubiquitous red dust after that three weeks… more
