Applet    ( in separate window, ca. 440 x 410 Pixel )

The applet displays

the displacement ( DSP_OUT )

and / or

the velocity ( VEL_OUT )

of the free motion of the moving mass of a seismometer

for different damping values of the system

and

for different initial condiditions

( displacement X(+0) and velocity V(+0) ).

The time axes is normalized to

T_0, the natural period of the ( undamped ) seismometer,

the velocity to

the circular natural frequency W_0 ( = 2 × π / T_0 ).

( Background : see Seismometer Documentation )

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Dialogue Window :
( Screenshot )

The Parameters of the output signals 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 initial displacement and velocity of the moving mass are selected from INITIAL CONDITIONS :

X(+0) = 1 / V(+0) = 0,

X(+0) = 0 / V(+0) = 1,

X(+0) = 1 / V(+0) = 1,

or

X(+0) = 1 / V(+0) = -1.

Comparison of output signals :

With DAMPING = 0.2 ... 2.0, the output signals

of one type of output ( SEISMO OUT ) and

for one initial state ( INITIAL CONDITIONS )

are displayed simultaniously

for five different values of seismometer damping,

with SEISMO OUT = DSP+VEL, the signals

for one damping value ( DAMPING ) and

for one initial state ( INITIAL CONDITIONS )

are displayed

for both displacement and velocity output,

and with INITIAL CONDITIONS = X/V: 1/0+..., the signals

for one damping value ( DAMPING ) and

for one type of output ( SEISMO OUT )

are displayed siultaneously

for four sets of initial conditions.

CLEAR TEXT ...

clears the text area of the applet,

lists the actually selected output signals in the range 0.00 ... 4.00 of normalized time ( LIST OUTP. ),

and

displays the time and velocity normalization ( DISP NORM. ).

PLOT

shows / hides the graphic display of output signals.

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.

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Graphic Display :
( Screenshot SEISMO OUT = DSP+VEL )

The time scale is normalized to

the natural period T_0 of the ( undamped ) seismometer,

the velocity to

the circular natural frequency W_0 = 2 × π / T_0

( see screenshot text area, below ).

( Background : see Seismometer Documentation )

Text Area :
( Screenshot DISP NORM. )

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

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