Suitability of Short-Period Sensors for Retrieving Reliable H/V Peaks for Frequencies Less Than 1 Hz

Seismic response of an 8-story RC-building from ambient vibration analysis

“…The PDF shows that, for frequencies above 1Hz, the level of noise during the measurements is close to the upper limit of Peterson noise model (Peterson, 1993), and well above the self-noise of the instrument (e.g. Strollo et al, 2008a., Strollo et al, 2008b. The narrow spread around the mode values shown by the PDF evaluated for the roof recordings confirms the stability of the spectral features over the analyzed time window.…”

On the suitability of 1 s geophone for ambient noise measurements in the 0.1–20Hz frequency range: experimental outcomes

“…More recently, a systematic comparison of H/V results obtained combining several different sensors and acquisition systems was done by Guillier et al (2007), while Strollo et al (2008), using a theoretical approach, and Marzorati et al (2006) who used empirical analysis, focused their attention on the influence of the short-period sensors spectral ratio results for frequencies lower than 1 Hz. Although the authors stated that this problem might come from a malfunctioning of the instrument they had at hand "It can however be a problem linked only to this particular seismometer used for the tests and no to any M1 seismometers" (Guiller et al 2007, paragraph 5.4), we were somewhat alarmed since most of our previous studies were carried out with this kind of geophone.…”

“…Data were recorded with a sampling rate of 100 samples per sec and a gain of 10 was set for the channels occupied by the Mark sensors, since this value was shown to be optimal for increasing the signal-to-noise ratio in the frequency band lower than 1 Hz by Strollo et al (2008). The acquisition design is shown in Figure 1.…”

Improving the spatial resolution of ground motion variability using earthquake and seismic noise data: the example of Bishkek (Kyrgyzstan)

“…According to Strollo et al (2008), the HVSR of the noise peak at lower frequencies obtained by such a sensor is always biased due to the strong filtering effect of the geophone, leading to lower spectral ratio amplitudes at frequencies less than 0.5 Hz. Hence, this station is not considered in further analysis.…”

“…In fact, the resonance frequency of the studied area is expected to be around 0.1-0.2 Hz, considering the thickness of the sedimentary cover underlying the city. Strollo et al (2008) has shown the reliability of the H/V results down to frequencies of about 0.1 Hz when using 1 Hz sensors combined with EDL digitizers. Also, the comparison of the self-noise of the instrument with the measured seismic noise (not shown here) confirmed the reliability of the results down to frequencies about 0.1 Hz.…”