david32:
I am glad to see that you have an extended interest in the geotechnical engineer's role in your project. When it comes to site analysis for seismic purposes we typically measure the shear wave velocity so that the sturctural can assign the proper site classification based on IBC, NEHRP...
mrwgeo:
Sorry for the delay, I have been away from the office - out in the field measuring shear waves.
We measure refraction microtremors generated by ambient background 'noise' such as trucks on a highway or anything that vibrates the ground a bit. The data is recorded for relatively long...
We routinely provide the IBC, NEHRP seismic site classification because the information is valuable to our clients (even though many have not yet recognized this). The problem is that assigning the classification requires judgment of conditions to 30 meter depth. Most geotechnical projects do...