The structures we build on Mars will be made to anticipate the Martian conditions. Most of the structures we have here on earth were not built to anticipate an

The structures we build on Mars will be made to anticipate the Martian conditions. Most of the structures we have here on earth were not built to anticipate an asteroid impact. Usually it is known beforehand when an asteroid will collide. We might not manage to build structures quickly enough to save all humans, and the resulting scramble for the few spots in the bunkers might destroy them. There also won't be any time to test the design and subsequently improve it. On Mars we have plenty of opportunity to measure the environment. Even if the worst happens, we can still repopulate the colony from earth, as long as our society is not being scared by such failures and stops manned Martian efforts completely.