There's a link below with detail info on Mori siesmograph - here's one little bit of info:
Question 4:
The site mentions that "The full vertical range of the screen represents 0.0005 mm/s
of ground motion." For us folks on the street, what kind of everyday-events that
compare to? For instance, roughly what kind of ground motion does a passing truck
or bus cause?

Answer:
In general, what you are seeing is what we consider "noise". The sensor is quite
sensitive and will record signals generated by storm fronts moving through, by high
surf along the coast, by temperature variations from night to day, and by the
gravitational tides of the Moon and Sun. You can occasionally see instances where
our engineers have gone in to inspect the instruments. In general, however, you are
just seeing the response of the Earth. For time to time, you will see an earthquake. I
haven't managed to catch one on Memento Mori. But you see examples of these
(displayed in a different way) at
http://quake.geo.berkeley.edu/bdsn/seismograms.html Since Feb, I think the largest
signal was caused by the Balleny Islands earthquake, a magnitude 8.2 event near
Antartica. The size of the signal is a function of both the earthquake magnitude and its
distance from our recording site. A very small earthquake, right under the station,
would probably generate a larger signal. That particular earthquake generated a
maximum signal of 2 millimeters/sec. During an earthquake, both the amplitude and
the frequency content of the plot will change. The amplitude will probably exceed
the bounds of the current plot, so it may be difficult to see the event completely.

• Mori Info