A wideband magnetoresistive sensor for monitoring dynamic fault slip in laboratory fault friction experiments

Sensors
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Abstract

A non-contact, wideband method of sensing dynamic fault slip in laboratory geophysical experiments employs an inexpensive magnetoresistive sensor, a small neodymium rare earth magnet, and user built application-specific wideband signal conditioning. The magnetoresistive sensor generates a voltage proportional to the changing angles of magnetic flux lines, generated by differential motion or rotation of the near-by magnet, through the sensor. The performance of an array of these sensors compares favorably to other conventional position sensing methods employed at multiple locations along a 2 m long × 0.4 m deep laboratory strike-slip fault. For these magnetoresistive sensors, the lack of resonance signals commonly encountered with cantilever-type position sensor mounting, the wide band response (DC to ≈ 100 kHz) that exceeds the capabilities of many traditional position sensors, and the small space required on the sample, make them attractive options for capturing high speed fault slip measurements in these laboratory experiments. An unanticipated observation of this study is the apparent sensitivity of this sensor to high frequency electomagnetic signals associated with fault rupture and (or) rupture propagation, which may offer new insights into the physics of earthquake faulting.

Publication type Article
Publication Subtype Journal Article
Title A wideband magnetoresistive sensor for monitoring dynamic fault slip in laboratory fault friction experiments
Series title Sensors
DOI 10.3390/s17122790
Volume 17
Issue 12
Year Published 2017
Language English
Publisher MDPI
Contributing office(s) Earthquake Science Center
Description Article 2790; 29 p.
First page 1
Last page 29
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