High efficiency portable seismograph for measuring seismic tremor

The tromograph is a seismograph of extremely high sensitivity aimed at recording the soil background tremor which is always present everywhere over a large frequency band. On the exact contrary, seismologists traditionally reject the soil background tremor, which consider a nuisance calling it "seismic noise". Designing an instrument aimed at measuring what is routinely discarded may seem a bizarre idea. It is not at all: recent progress in theoretical Acoustics demonstrates that seismic “noise” is composed of what theoretical physicists call "Diffuse Waves", which means waves that have completely lost all information about their source but retain accurate information on local subsoil stratigraphy or, in buildings, on their structure. The patent discloses a new class of instruments which is capable, in some minutes of totally unobtrusive recording of background tremor, to draw an "ecographic" image of subsoil down to depths of several hundred meters, as well as to accurately measure (modal analysis) the vibratory eigenfrequencies of any building.