|Type of parameter||Main Recommendations|
|Recording duration||Minimum expected f0(Hz)||Recommended minimum recording duration (min)|
|Measurement spacing||Microzonation: start with a large spacing and, in case of lateral variation of the results, densify the grid point.|
Single site response: never use a single measurement point to derive f0 value, make at least three measurement points.
|Recording parameters||Level the sensor as recommended by the manufacturer.|
Fix the gain level at the maximum possible without signal saturation.
|In situ soil-sensor coupling||Set the sensor down directly on the ground, whenever possible.|
Avoid setting the sensor on “soft grounds” (mud, plowed soil, tall grass, etc.) or soil saturated after rain.
|Artificial soil-sensor coupling||Avoid plates from “soft” materials such as foam rubber, cardboard, etc.|
On steep slopes that do not allow correct sensor leveling, install the sensor in a sand pile or in a container filled with sand.
On snow or ice, install a metallic or wooden plate or a container filled with sand to avoid sensor tilting due to local melting.
|Nearby structures||Avoid recording near structures such as buildings, trees, etc. in case of wind blowing (faster than about 5 m/s). It may strongly influence H/V results by introducing some low frequencies in the curves.|
Avoid measuring above underground structures such as car parks, pipes, sewer lids, etc.
|Weather conditions||Wind: protect the sensor from the wind (faster than approx. 5 m/s). This only helps if there are no nearby structures.|
Rain: avoid measurements under heavy rain. Slight rain has no noticeable influence.
Temperature: check sensor and recorder manufacturer’s instructions.
Meteorological perturbations: indicate on the field sheet whether the measurements are performed during a low-pressure meteorological event.
|Disturbances||Monochromatic sources: avoid measurements near construction machines, industrial machines, pumps, generators, etc.|
Transients: in case of transients (steps, cars, etc) increase the recording duration to allow for enough windows for the analysis, after transient removal.