Geology 492/692 Field Project Hoping to put Fernley and Hazen on the Fault Map ReMi Data

Refraction Microtremor (ReMi) Method Developed to provide quick an easy site specific shaking hazard assessment. Uses microtremor noise as source. Rayleigh-wave phase-velocity dispersion curves are picked to determine the slowest surface wave velocities at any given frequency. Forward modeled to produce a shear-velocity-depth sounding. Can estimate shear velocity with 20% accuracy to depths of up to 100m. Average V 30 can be estimated.

Using ReMi to Find Faults? Theoretically possible if fault offset displaces units with observably different shear wave velocities. Might be able to detect rubble zones or flower structures. Likely not a marketable method for fault hunting.

This Study Characterized V 30 at 20 sites. –8 Northern Fernley Hills –12 Hazen Flat Fernley studies conducted with 24 channel, 10 m spacing, Bison line. Hazen Studies conducted with a 20 Texan, 10 m spacing array.

Location

Results (Fernley)

Results (Hazen)

Data Comparison (Fernley West)

Data Comparison (Fernley East)

Data Comparison (Hazen South)

Data Comparison (Hazen North)

Conclusions ReMi “anomalies” do align themselves with observed anomalies from other techniques about 75% of the time. However, ReMi did not confidently determine the location of any structures. Best as a corroborative technique for fault hunting.