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arXiv · 1901.01219

On the origin of thigh-frequency radiation in experimental earthquakes

S. Marty·F. X. Passelègue·J. Aubry·H. S. Bhat·A. Schubnel·R. Madariaga
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Abstract

We monitor dynamic rupture propagation during laboratory stick-slip experiments performed on saw-cut Westerly granite under upper crustal conditions (10-90 MPa). Spectral analysis of high-frequency acoustic waveforms provided evidence that energy radiation is enhanced with stress conditions and rupture velocity. Using acoustic recordings bandpass filtered to 400-800 kHz (7-14 mm wavelength) and highpass filtered above 800 kHz, we back projected high-frequency energy generated during rupture propagation. Our results show that the high-frequency radiation originates behind the rupture front during propagation and propagates at a speed close to that obtained by our rupture velocity inversion. From scaling arguments, we suggest that the origin of high-frequency radiation lies in the fast dynamic stress-drop in the breakdown zone together with off-fault co-seismic damage propagating behind the rupture tip. The application of the back-projection method at the laboratory scale provides new ways to locally investigate physical mechanisms that control high-frequency radiation.

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BibTeXRIS

S. Marty, F. X. Passelègue, J. Aubry, H. S. Bhat, A. Schubnel, R. Madariaga. 2019-01-04. On the origin of thigh-frequency radiation in experimental earthquakes. https://doi.org/10.1029/2018gl080519

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