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| Corona Heights playground, San Francisco is located in an abandoned quarry. |
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| The quarry excavated back to a slickenside (fault surface) that is now exceptionally well exposed. |
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| The whole wall in the photo above is polished and covered in slickenlines of various types. |
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| I am studying the orientation of the slickenlines to investigate the stresses that drive opposing sides of the fault past each other during slip events. To do this, I scanned the cliff with a ground based LiDAR. The slickenlines typically have amplitudes smaller than the precision of the range measurements by the LiDAR. To enable detection of the slickenlines in the LiDAR data Nicholas (left) and I rappelled down the cliff placing Duct tape along the slickenlines. |
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| The height of the cliff is around 18m. We placed several hundred pieces of tape. |
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| The LiDAR in action. It collects measurements of the position of millions of points on the fault surface to define the shape of the surface. |
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| The fault cuts Franciscan chert that forms a hill close to down town San Francisco. The view from the top is great (as long as the fog stays away!). |
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