Zero average velocity

Looking at the data of some older shake 1d, I do see that the velocity on graphs is centered around 0.0

The recent v8 1d do show an offset of 16000 is raw data and 4.1E-5 M/S in velocity.

Is this on purpose, is there a way to get it zeroed ?

thank you

Hello benoitschillings,

Thank you for bringing this matter to our attention. I have passed your observations to our hardware and software teams so that they will be able to focus on what could be causing this.

I will update you as soon as I have some data from them.

Thank you again!

bonjour benoit,

the first version of the 1D has a sample rate of 50hz. for all subsequent versions and other Shake models, data is delivered at 100hz. due to this change in sampling rate, and because of how ADCs work, this offset is, in fact, necessary.

normally, when processing raw seismic data, software will demean the data to remove any offset which may or may not exist since there is no guarantee that incoming data will be centered around zero.

if you want to demean this data yourself, you can take the average of the data points over some period of time and remove this value from all the data points in the time window of data being processed.


thank you. I see that this is now zero centered ! Just took place in the last day or so.