High magnetic susceptibility produced in high velocity frictional tests on core samples from the Chelungpu fault in Taiwan

Geophysical Research Letters Volume 34 Page L15304- published_at 2007
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Title ( eng )
High magnetic susceptibility produced in high velocity frictional tests on core samples from the Chelungpu fault in Taiwan
Creator
Tanikawa Wataru
Mishima Toshiaki
Hirono Tetsuro
Lin Weiren
Shimamoto Toshihiko
Soh Wonn
Song Sheng-Rong
Source Title
Geophysical Research Letters
Volume 34
Start Page L15304
Abstract
We carried out high-velocity frictional tests on crushed fault gouge from core samples from Hole B of the Taiwan Chelungpu-fault Drilling Project to investigate the cause of high magnetic susceptibilities in the fault core. Black ultracataclasite resembling that observed in Hole B formed during the experiments, even under low axial stress of 0.5 to 1.5 MPa. The bulk magnetic susceptibility of the tested samples was proportional to the frictional work applied and increased as slip increased. Thermomagnetic analysis of the samples before frictional testing revealed that magnetization increased at temperatures above 400 °C, probably because of thermal decomposition of paramagnetic minerals. Both the thermally and mechanically induced formation of ferrimagnetic minerals by high velocity friction might have caused a magnetic susceptibility anomaly. Our experimental results support the assumption that heat generation of short duration, even if it is below the melting point, can increase magnetic susceptibility.
Keywords
magnetic susceptibility
the Chi-Chi earthquake
frictional heating
NDC
Earth sciences. Geology [ 450 ]
Language
eng
Resource Type journal article
Publisher
American Geophysical Union
Date of Issued 2007
Rights
Copyright (c) 2007 American Geophysical Union
Publish Type Author’s Original
Access Rights open access
Source Identifier
[ISSN] 0094-8276
[DOI] 10.1029/2007GL030783
[NCID] AA00657102
[DOI] http://dx.doi.org/10.1029/2007GL030783