Matrix imaging as a tool for high-resolution monitoring of deep volcanic plumbing systems and fault areas

Volcanic eruptions necessitate precise monitoring of magma pressure and inflation for improved forecasting. Imaging the structure of major fault zones is essential for our understanding of crustal deformations and their implications on seismic hazards. Yet imaging those systems is challenging due to complex heterogeneities that disrupt standard seismic migration techniques. Here we map the magmatic system of the La Soufrière volcano in Guadeloupe 1 and the subsurface structure of the San Jacinto Fault zone (SJFZ) in California 2 by analyzing seismic noise data from a geophone array under a matrix formalism. Seismic noise interferometry provides a reflection matrix containing the signature of echoes from deep heterogeneities. Using wave correlations resistant to disorder, matrix imaging successfully unscrambles wave distortions, revealing La Soufrière and SJFZ’s internal structure down to 10 km with 100 m resolution. This method surpasses the diffraction limit imposed by the geophone array aperture, providing crucial data for modeling and high-resolution monitoring. We see matrix imaging as a revolutionary tool for understanding the dynamics at work in volcanic systems and fault areas as well as for forecasting eruptions and earthquakes. 1 E. Giraudat et al., Commun. Earth Environ. 5, 509 (2024). 2 R. Touma et al., Geophys. J. Int., 2021, 780–794 (2021).