The ReMi (Refraction Microtremor) method is a geophysical test used to determine the distribution of shear wave propagation velocity values with depth.

The Vs30 value is required for seismic soil classification of the foundation ground, as established in DS N°61, which modified the seismic design standard for buildings NCh 433 Of.96.

The method essentially consists of equipment that includes: a 24-channel digital seismograph, low-frequency geophones, special connection cables, and software such as Vscope, ReMi Spect 4.0, and ReMi Dipsert V4.0.

From the Vs values, some geotechnical properties can be estimated, and immediately the dynamic shear modulus (G), using the expression G = γ × Vs², where “γ” is the soil density.

Depending on the soil material properties, the ReMi method can reach depths ranging from 30 up to 100 m using standard instrumentation.

The seismic wave source is ambient noise, and the ReMi method uses Rayleigh surface waves generated by microtremors.

Decree DS61 requires obtaining dispersion curves and the results of velocity profiles with depth for two preferably orthogonal measurements. Specifically, for the ReMi method, it must include one measurement with an active source of known location. The shear wave velocity profile that characterizes the site will correspond to the one that results in the most unfavorable case.