Remote sensing of tectonic induced stress across faults using high energy muon beams

Abstract

We illustrate a theoretical study of a newly conceived technique using high-energy muon beams (TeV-class) propagating through thick (km-long) crystalline rock layers subject to tectonic-induced stress, potentially capable of actively monitoring the temporal evolution of the pressure rise in seismic fault zones associated with earthquake triggering when the induced tectonic pressure reaches and overcomes the rock elasto-plastic deformation limit. This technique could contribute to improving earthquake forecasting statistics in seismically active regions, offering support for seismic hazard assessment and prevention strategies. Active monitoring of the induced tectonic stress and its time evolution is achieved by remote sensing of the electric field generated in quartz crystals embedded in crystalline rocks by piezoelectric effects. In this context, tectonic pressure refers to the time-dependent stress field acting on the rock body due to tectonic forces, which adds to the time-independent lithostatic pressure resulting from the weight of overlying materials. High-energy muon beams transmitted through a rock layer subject to tectonic pressure will be affected in their transverse phase space distributions by the piezoelectric fields, therefore transferring to a detector the information on the applied tectonic stress. Finally, we illustrate the design of a proof-of-principle experiment to be conducted in a standard accelerator laboratory, using moderate-energy muons (GeV-class) propagating through granite slabs subject to a press-induced stress reaching the rupture limit. A zero-generation proof-of-principle test can also be performed using 20-150\,MeV electron beams transmitted through single quartz crystals subject to variable pressure.