A formidable tool for microtremor and site response

Microzoning site effects, resonance frequency HV

Vs30 bound to fit the H / V curve

Use a regular notebook PC

It weighs 1,560 grams (the weight is an important element)

.saf file format suitable for all post-processing software on the market

With the purchase will have a 40% discount on HVSR Geostru software

For italian customers is recommended the following book:

MODELLAZIONE DEL SOTTOSUOLO CON LA GEOFISICA APPLICATA ALLE ONDE DI SUPERFICIE (Edito EPC)

Just follow www.winmasw.it 

SURFACE WAVE ANALYSIS FOR NEAR SURFACE APPLICATIONS

ONDE DI SUPERFICIE IN GEOFISICA APPLICATA  di Giancarlo Del Moro

INVESTIGATIONS OF PASSIVE SEISMIC - HVSR 
This technique is essentially based on the spectral ratio H / V of environmental noise (seismic noise) and it allows to evaluate the local effects of the site. To measure provides for the registration, without the use of energization, the environmental seismic microtremor in the time domain on te components of the JEATROM space.

The JEATROM has the following specifications:

3D transducers (N-S, E-W, vertical Z) low frequency 2.0 Hz and 4.5 Hz

Frequece from 250-500 Hz sampling always> 50Hz

converter 24-bit A / D  a few hours of recording time> 15 minutes

METHOD EXECUTIVE

The JEATROM must be oriented before - east / west - fitted with spikes, to be anchored to the ground and leveled.

Note the presence of buildings, underground utilities, wind, roots, since they create disorder in the H / V signal.

The recorded file is .saf type and can be processed by software on the market and enables the determination of the resonant frequencies of the subsurface through technical spectral ratios according to guideline of european SESAME project.

The main steps of the processing are as follows:

FFT (including tapering)

operator smooothing

mergin of horizontal components

H / V Spectral Ratio for more window  (> 10)

average of the spectra H / V

vlutazione standard deviation.

DOCUMENTATION

the criteria of reliability of the measurement criteria of validity of the peak the threshold values ​​of the stability conditions analysis of criter iin particolar  occurs with respect to the frequency of the sensor and to the presence of noise of industrial origin interpretation of  the H / V spectrum in terms of site features evaluation homogenuity of site in relation to the resonance frequencies thickness of the cover layer.

NEW PRODUCTION 3 COMPONENTS WITH MEMS XYZ 

FROM 0.1 Hz TO 800 Hz