Phase tensor ellipses and induction vectors. Large ellipses denote observed phase tensor ellipses, whereas small ones in the background denote synthetic ellipses at respective virtual sites, which were calculated from the 3-D resistivity model. The color of the ellipse denotes Φmin, Φmin, and β for (a), (b), and (c), respectively. Purple arrows in (c) denote the observed real part of Parkinson's induction vectors (Parkinson 1962). Note that we exclude observed values showing large error exceeding 5°, 5°, 2°, and 0.05 for Φmin, Φmax, β, and induction vector, respectively.