Horizontal Vertical Spectral Ratio – EASY HVSR

Description

Software for HVSR processing

Customizing analysis
The user can choose different ways in which process the data, choosing the more appropriate methods for the directional sum of the traces in the horizontal directions, for the smoothing and for the frequency band to be analyzed. Among the directional sums available the user can choose from the most simple arithmetic mean to the amean square or geometric mean. Among the methods for data smoothing suggested by the SESAME project can be chosen: Konno & Ohmachi, Triangular constant and Triangular proportional. The user can choose the time windows to include or exclude with a simple checkmark, seeing in real time the changes made. The input data can be automatically filtered.

Displaying Data
All results are displayed in customizable charts. The available charts are: the traces in the three directions analyzed with the representation of the time windows chosen; the average spectrum of the traces; the map for the verification of the recording’s stationarity; the map for the verification ot the recording’s directional isotropy; the spectral ratio H/V with its confidence interval, having the with possibility to overlap the ellipticity curve of more stratigraphic models not only of the fundamental mode but also higher ones; he graphical representation of the stratigraphic profile; the velocity profile associated with the stratigraphy.

Results
The software automatically evaluates a first estimate of the stratigraphic model that best approximates the H/V spectral behavior recorded in situ and analyzed so the user can refine it with greater rapidity.Is thus obtained, in addition to the natural vibration frequency of the stratigraphy typical to HVSR technique, the immediate assessment of Vs30 and of the shear wave velocity profile of the stratigraphic model assumed. On the chart of the spectral ratio H/V are visible, in addition to the H/V curve with its confidence interval, all the ellipticity curves of the of the various modes of each stratigraphic model that the user can decide to add. In this way it is possible to compare the differences from a qualitative point of view, and in addition also a quantitative comparison with the estimate the mismatch function between the ‘fundamental’ ellipticity curve and the curve of the spectral ratio H/V. All accompanied by the checks on the reliability of the H/V curve and its peak suggested by the SESAME project.