Helicorder Comparison


From time to time I compare my helicorder to a station that is maybe several miles away from mine. I assume our data would be similar in regard to P and S wave arrivals. I compared the following and the appearance of the seismogram at the same selected times look different. The one on the left is my station. Any possible reasons as to why?


Hello mcesaire,

P and S waves arrivals can depend on many different factors (such as soil composition, bedrock depth, etc.) but yes, in general, close stations will ‘see’ very similar arrival times.

However, the case that you have shown does not seem to represent a natural event (I cannot be sure without seeing the spectra data), and the station you are comparing your trace to seems to have been put in a noisier environment compared to yours. Most likely, what are you seeing in the second helicorder is the result of local noise (such as traffic, machinery, plants, etc.) and thus not comparable with your Shake recordings.

I can advise you to wait for a strong enough earthquake to be recorded by both the stations you are looking via SWARM, and the comparison will be much easier.