Abstract
The seismic activity of a planet can be described by the corner
magnitude, events larger than which are extremely unlikely, and the
seismic moment rate, the long-term average of annual seismic moment
release. Marsquake S1222a proves large enough to be representative of
the global activity of Mars and places observational constraints on the
moment rate. The magnitude-frequency distribution of relevant Marsquakes
indicates a b-value of 1.17, but with its uncertainty and a volcanic
region bias, b=1 is still possible. The moment rate is likely between
1.5e15 Nm/a and 1.6e18 Nm/a, with a marginal distribution peaking at
4.9e16 Nm/a. Comparing this with pre-InSight estimations shows that
these tended to overestimate the moment rate, and that 30 % or more of
the tectonic deformation may occur silently, whereas the seismicity is
probably restricted to localized centers rather than spread over the
entire planet.