Developing stress-monitoring sites using cross-hole seismology to stress-forecast the times and magnitudes of future earthquakes

A review of shear-wave splitting in the compliant crack-critical anisotropic Earth

“…7, and in changes before earthquakes [25,35,46], the criticality is implied. The only direct observations of extreme compliance are from a prototype stress-monitoring site (SMS) [71] measuring shear-waves in cross-hole seismics between boreholes, adjacent and parallel to the Húsavík-Flatey transform fault of the Mid-Atlantic Ridge in northern Iceland [7]. A calibration test measuring travel times horizontally at 500 m depth between boreholes 315 m-apart happened to coincide with a 4-day swarm of small earthquakes with energy equivalent to a single M ≈ 3.5 earthquake on a parallel transform fault 70 km NNW [7].…”

A review of the New Geophysics: a new understanding of pre-fracturing deformation in the crack-critical crust with implications for hydrocarbon production

“…The expected sensitivity and compliance of the New Geophysics has been directly confirmed by a cross-hole experiment in a prototype borehole Stress-Monitoring Site (SMS) for stress-forecasting earthquakes (Crampin, 2001). The "SMSITES" SMS near the Húsavík-Flatey transform fault of the Mid-Atlantic Ridge in Northern Iceland recorded horizontal seismic travel times at 500 m-depth between boreholes offset 315 m .…”

Shear-wave splitting in a critical crust

“…The European Commission-funded SMSITES Project is developing a stress-monitoring site (Crampin, 2001) on the onshore extension of the Húsavík-Flatey Fault (HFF), which is a transform fault in the Tjörnes Fracture Zone of the Mid-Atlantic Ridge in Northern Iceland. The aim was to transmit shear waves along specific stress-sensitive directions in order to try to identify the small changes in microcrack geometry, which APE shows are the most immediate effects of accumulating stress, before failure by fracturing occurs.…”