Felsignals

Felsignals is a term used in geophysics to describe seismic and acoustic signals generated by deformation, cracking, and failure in rocks. The concept appears in certain mining and regional seismology literatures and is not universally adopted as a formal category in mainstream seismology.

Typical sources of felsignals include microcracking within rock masses, imminent rockbursts in underground mines, and faulting-related crack propagation in crustal rock. They are recorded using geophones, accelerometers, or broadband seismometers and are analyzed in time, frequency, and waveform domains to infer damage processes and estimate energy release.

Measurement and analysis rely on standard signal-processing techniques, including filtering, waveform polarization, and event detection. Common workflows employ short-term/long-term average detectors, spectral analysis, and, when possible, event relocation to map active zones. Amplitude scaling and calibration relate signal strength to relative fracture effort.

Applications focus on monitoring rock stability in mining, civil engineering, and deep excavation projects, where felsignals can contribute to early-warning schemes or post-event assessment of damage. In research contexts, they help illuminate fracture mechanisms and the temporal evolution of rock failure under varying stress conditions.

Limitations include noise contamination, heterogeneous media, and ambiguity in source mechanics. The term remains informal in many regions, and researchers often prefer broader categories such as microseismicity or rock-mquake signals. Ongoing work seeks standardized definitions, improved instrumentation, and robust interpretation frameworks.