The Fracture Induced Electromagnetic Radiation (FEMR) technique as a tool for stress mapping: A case study of the Ramon Crater

This study explores the application of Fracture-Induced Electromagnetic Radiation (FEMR) for stress analysis in the Ramon Crater, a tectonically “stable” region in southern Israel. FEMR, an innovative geophysical method, detects electromagnetic pulses emitted during micro-fracturing events to infer stress orientations. Unlike traditional seismic techniques, FEMR is sensitive to subtle stress changes, making it suitable for regions with limited seismicity. Field measurements were conducted at nine locations using the ANGEL-M device, capturing high-sensitivity electromagnetic signals to determine the stress azimuth. The results revealed a dominant mean stress azimuth of 308°, aligning closely with the acute bisector of two principal joint sets in the region, WNW-ESE and NNW-SSE. These orientations correspond to historical compressional stress from the Syrian Arc Stress (SAS) regime and more recent extensional stress from the Dead Sea Stress (DSS) field. The superimposition of these regimes has created a complex tectonic environment, evidenced by features such as joint sets, fault planes, and basaltic dikes. FEMR measurements correlate with these geological indicators, confirming the technique’s ability to detect regional stress directions and their evolution over time. In the past decade, the method of FEMR has progressively gained impetus as a viable, non-invasive, cost-effective, real-time geophysical tool for stress analysis in various parts of the world. Its range lies in delineating tectonically active zones, landslide-prone weak slip planes, highlighting stress accumulation in mines and tunnels, etc. This study highlights FEMR’s viability for stress field analysis, especially in stable tectonic zones. Its ability to capture micro-crack activity and subtle stress shifts offers a detailed understanding of how tectonic forces shape regional geodynamics. While FEMR enhances stress detection capabilities, careful calibration with geological models is essential to differentiate transient stress changes from long-term tectonic trends. This research advances FEMR’s application in geophysical studies, particularly for monitoring stress fields in regions influenced by ancient and ongoing tectonic forces.