(a) ISS basemap of the SPT on which has been plotted the color-coded relative magnitudes of predicted time-averaged shear stresses. Yellow is the largest, and purple is the smallest. An isolated region of high shear stress is circled. (b) ISS basemap of the SPT on which has been plotted the color-coded relative magnitudes of predicted maximum normal stresses. Yellow is the largest, and purple is the smallest. See the text.