Luminescence and Esr Dating of Fault Gouge Materials from the Nojima Fault -

This study is the first part of a comprehensive palaeoseismic study in the Nojima fault-Japan, which explores the use of the luminescence dating techniques and Electron Spin Resonance (ESR), focusing on methodological aspects of the techniques and reports on a series of luminescence and ESR ages of fault gouge samples. Our approach in this preliminary study was to date fine and medium size quartz and feldspar grains using Optically Stimulated Luminescence (OSL), Isothermal-Thermoluminescence (ITL) and ESR.

Our analysis suggests that both OSL and ITL can produce reliable dating results and are potentially excellent methods for direct dating fault gouges. Luminescence ages indicated the occurrence of neotectonic activity with repeated raptures at the Nojima fault, with ages ranging from 16.8 ± 1.4 ka to 59.1 ± 6.9 ka.

At the same time ESR dating appeared inappropriate for dating fault gouge materials using the E₁' and OHC centers, while the employment of the Al center was also proven to be problematic and should be considered only when resetting of the Al signal could be established. In this regard, it appears that luminescence signals can be reset at much lower temperatures than ESR Al centre, thus making luminescence more appropriate for dating fault gouge materials for which heating conditions at the time of rapture could not be clearly established.