Subject: Re: NEVADA EVENT ??? M2.7 ??? seen in Apache Junction ??


It is odd but I am unable to get a flat velocity response cheaply.
I guess my waveform is displacement below 1 Hz
nd Acceleration Above 1Hz,
nly right at 1Hz might you call it velocity.
What kind of seismometer is that ?
Hi Geoff,
    If you put your 1 Hz geophone onto a high impedance=20
non inverting amplifier input, you get a velocity=20
response above the resonant frequency. You then increase=20
the damping to ~critical by loading the geophone with=20
a damping resistor. This is necessary to flatten out the=20
high frequency response.=20
Regards,
Chris Chapman





=
Subject: Re: NEVADA EVENT ??? M2.7 ??? seen in Apache Junction ??





It is =
odd but I am unable to get a flat velocity response cheaply.

I guess my waveform is displacement below 1 Hz
and Acceleration Above 1Hz,
Only right at 1Hz might you call it velocity.

What kind of seismometer is that ?

Hi Geoff,
    If you put your 1 Hz geophone onto a high impedance 
non inverti=
ng amplifier input, you get a velocity 
response above the resonant frequency. You then increase 
the damping to ~critical by loading the=
 geophone with 
a damping resistor. This is necessary to flatten out the 
high frequency resp=
onse. 
Re=
gards,
Ch=
ris Chapman