Regional geological mapping commonly records the dip and dip direction of dominant layering such as bedding and foliation but not the orientation of joints. It is common for joints to form an orthogonal pattern relative to the dominant layering. In that case, the three-dimensional possibilities can be extrapolated allowing inferences to be made about kinematically feasible structural failure mechanisms. The resulting planar sliding, wedge sliding and toppling kinematic assessment can be integrated on a stereograph. The analysis of extrapolated joint sets can be conducted in the initial desk-top stage of a site investigation. The method is demonstrated using field data from Devonian sandstones in eastern Victoria, Australia. The sandstones have joint sets and partings on axial cleavage orthogonal to bedding. The range of potential structural failure mechanisms is extrapolated from the known bedding orientation and slope face direction.

区域地质测绘通常记录主要分层（例如层理和页岩）的倾角和倾角方向，而不记录节理的方向。关节相对于主要层形成正交图案是很常见的。在那种情况下，可以对三维可能性进行推断，从而可以推断出在运动学上可行的结构破坏机制。所得的平面滑动，楔形滑动和倾覆运动学评估可以集成在立体图上。外推关节组的分析可以在现场调查的初始台式阶段进行。使用澳大利亚维多利亚州东部泥盆纪砂岩的现场数据证明了该方法。砂岩在与地层正交的轴向开裂处有节理和分形。