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Ogata, Manabu; King, G. E.*; Herman, F.*; Yamada, Ryuji*; Omura, Kentaro*; Sueoka, Shigeru
no journal, ,
Optically stimulated luminescence (OSL)-thermometry can be used to reconstruct the thermal structure in slowly denuded regions where infrared stimulated luminescence (IRSL) signals of samples obtained from deep boreholes are measured and evaluated with depth. Only one study had explored this approach, using a target mineral of Na-feldspar. We applied multi-OSL-thermometry to K-feldspar obtained from deep borehole core samples drilled at the Tono (MIZ-1) and Rokko regions (Kabutoyama), which are well-documented thermally stable crustal environment. For the K-feldspar obtained from the MIZ-1 core, the inverted temperatures for the IRSL50 
C of the samples at a depth of 
1 km (40 C) were consistent with the in-situ temperatures. The results suggest that the application of OSL-thermometry to K-feldspar in a borehole is useful to reconstruct the palaeothermal condition. In this presentation, we will also show the results of the Kabutoyama core to draw more comprehensive conclusions.
Bartz, M.*; King, G. E.*; Herman, F.*; Anderson, L.*; Sueoka, Shigeru; Tsukamoto, Sumiko*; Tagami, Takahiro*
no journal, ,
' center by experimental fault slipsTanaka, Kiriha; Ohashi, Kiyokazu*; Muto, Jun*; Oka, Toshitaka
no journal, ,
Electron spin resonance (ESR) dating of a fault assumes that charge trapping centers in quartz in a fault material have been completely annihilated by the seismic fault slip (ESR signal zeroing). There is little understanding of the relationship between the signal zeroing and fault parameters. The previous high-velocity friction (HVF) experiments have implied that the E' center in quartz could be correlated with frictional power density and begin to decrease at a power density of 0.60.9 MW/m
. However, the data was lacking to confirm the signal zeroing at higher power density. We performed HVF experiments for simulated quartz gouges with a slip rate of 1 m/s, a displacement of 10 m, and normal stresses of 1.02.5 MPa. ESR measurements were conducted for gouges before and after experiments. The peak-to-peak height of the E' center calibrated by that of the standard material was calculated as the ESR intensity (ESR intensity ratio) of the E' center. The ESR intensity ratio of the E' center decreased with increasing frictional power density of 0.961.4 MW/m. The maximum temperatures near the sliding surface were 260C at 0.96 MW/m, 600C at 1.0 MW/m, and 480C at 1.6 MW/m. The E' center is thermally unstable at 
300C and more unstable at higher temperatures. Hence, the ESR intensity ratio might decrease due to larger frictional heating with increasing power density. Comparing our results with those in the previous study, the ESR intensity ratio clearly decreased with increasing power densities of 0.61.4 MW/m. HVF experiments mimic seismic fault slips of earthquakes with a moment magnitude of 89 at shallow depths of 
100 m. Seismic fault slip of an earthquake at a depth of at least one hundred meters under the earth's surface can be required for ESR signal zeroing of the E' center.
King, G. E.*; Wen, X.*; Bartz, M.*; Bossin, L.*; Tsukamoto, Sumiko*; Li, Y.*; Herman, F.*; Ogata, Manabu; Sueoka, Shigeru
no journal, ,