Rational people likes categorizing things. Landslides and earthquakes are two phenomenon which are distinct, and when you focus on earthquake you don't take into account the role that mass movements may induces.

This is untrue. Since the prior works of many geologists (synthetized first in 1984 by Keefer) it is now well known that seism trigger mass movements. The example of the 2008 Beichuan earthquake is exemplary. A large ratio of fatalities are due to landslides following the main shock. The picture below are self explicit ...