Just like Earth, movement of tectonic plates can lead to seismic activity, and just like on Earth there are different locations where this activity can occur. On the 25th of August 2021, InSight found two Marsquakes - one magnitude 4.2 event which occurred around 8500 KM away from the lander, and one magnitude 4.1 event which was around 925 km away. These different quakes at different distances can tell scientists a lot about the depth and thickness of the planet’s crust plus the size of its molten core.
Although there’s evidence of quakes on the Moon, and evidence of historical quakes on Venus, it wasn’t until InSight lander in 2019 that marsquakes were definitively observed. The Viking program in the 70’s operated for several years, but due to the seismographs being top mounted it was difficult to determine the differences between seismic activity or strong winds and nothing could be confirmed. Some marsquakes can also be caused by meteorite impacts and the ground tremors they in turn cause, with larger impacts causing a bigger disturbance and more extreme damage.
Marsquakes have both the highest minimum and maximum intensity of all hazards, and on top of this they deal more damage than other hazards too. All cards are vulnerable to marsquakes, so a powerful quake can cripple the colony and lead to a significant drop in earning power until cards have been repaired and reactivated.
Marsquake hazards inflicts 75 points of damage each time they damage an ownership/sponsorship card.