Fig. 6

Applications of TSpin for a stepwise thermal demagnetization for a historical 1763 scoria and b Thellier paleointensity measurement for a recent 1983 lava flow in Miyakejima, Japan. In the Zijderveld diagrams, directions are shown in the sample coordinates, and solid and open circles denote vector end points projected on horizontal and vertical planes, respectively. In an Arai diagram, open squares show points of partial thermoremanence (pTRM) checks. Numerals in the diagrams denote the temperature in \(^{\circ }\)C, and \({J_0}\) indicates the magnetization intensity before demagnetization. For a \({J_0}\) is \(5.11\, \times \, 10^{-4}\, \hbox {Am}^2\), and the maximum angular deviation for the 150–\(575\,^{\circ }\)C interval is \(0.8^{\circ }\). For b \({J_0}\) is \(2.36\, \times \, 10^{-4}\, \hbox {Am}^2\), the maximum angular deviation for the 20–\(580\,^{\circ }\)C interval is \(0.8^{\circ }\), and paleointensity statistical parameters are \(f = 0.992\), \(g = 0.808\), and \(q = 121.3\) (Coe et al. 1978)