Applied Geophysics : Seismics

Frequency Response of a Seismometer

Applet ( in separate window, ca. 420 x 410 Pixel )

The applet displays amplitude and phase of the normalized frequency response of
  a displacement transducer ( DSP_OUT )
  and / or
  a velocity transducer ( VEL_OUT )
with respect to
  ground displacement, velocity and / or acceleration
for different damping values of the system.

( Background : see Seismometer Documentation )

HowTo Screenshots Download

- HowTo -

Dialogue Window :
( Screenshot )

The Parameters of the response to be displayed are selected in the parameter dialogue ( background light blue ) :

> The damping of the seismometer is
>   selected from ALP= 0.2 ... ALP= 2.0
> or
>   adjusted ( ADJUST ) between 0.001 and 99.999
>   ( DEC / INC, in steps of 10.0 ... 0.001 ).

> The output signal of the seismometer is selected from SEISMO OUT :
>   DSP_OUT = displacement transducer
> or
>   VEL_OUT = velocity transducer.

> The type of ground motion the response refers to is selected from RESP. TO... :
>   DISPLACEMENT
>   VELOCITY
> or
>   ACCELERATION.

> Comparison of response curves :

> With DAMPING = 0.2 ... 2.0, the response curves
>   of one type of output ( SEISMO OUT ) and
>   for one type of ground motion ( RESP. TO... )
> are displayed simultaniously
>   for five different values of seismometer damping,

> with SEISMO OUT = DSP+VEL, the curves
>   for one damping value ( DAMPING ) and
>   for one type of ground motion ( RESP. TO... )
> are displayed
>   for both displacement and velocity output,

> and with RESP TO... = DSP + VEL + ACC, the curves
>   for one damping value ( DAMPING ) and
>   for one type of output ( SEISMO OUT )
> are displayed siultaneously
>   for ground displacement, velocity and acceleration.

CLEAR TEXT ...
  clears the text area of the applet,
  lists the actually selected transfer functions with 16 values per decade in the range 1.E-3 ... 1.E3 of normalized frequency ( LIST RESP. ),
  and
  displays the frequency normalization and the fomulae used for calculating the transfer fuctions ( DISP NORM. ).

HIDE ...
shows / hides the graphic display of response curves :
  AMPL => amplitude response,
  PHAS => phase response,
  and
  A + P => both.

INFO and HELP refer to the graphic display windows, where
  informations to the actual cursor position ( INFO )
and / or
  hints to actually possible mouse actions ( HELP )
are displayed.

Top of Page HowTo Screenshots Download

Graphic Display :
( Screenshots RESP. TO... = DSP+VEL+ACC )

The frequency scale is normalized to the natural frequency F_0 of the ( undamped ) seismometer
( see screenshot text area, below ).

( Background : see Seismometer Documentation )

Text Area :
( Screenshot DISP NORM. )

- Download -

Class and html files for a local installation of the applet are available as a zip file and as a tar.gz file.

More applets at : Geophysics Department TU Clausthal

Rev. 12-nov-2012

Comments to Fritz Keller
( ned gschempfd isch globd gnueg )

Top of Page HowTo Screenshots