Buildings built using unreinforced masonry, like solid brick buildings, are among the most unsafe types of buildings during an earthquake. These buildings are weak, and their walls can fall away during a strong earthquake. But how do you recognize solid brick buildings?
Header rows: Solid brick buildings will have header rows, or rows of "shorter bricks", every four to seven rows. These are also called "king rows":
Tie plates: you can see rafter tie plates on the exterior of the building:
Recessed windows: the windows of buildings with unreinforced masonry look like they've "sunk" into the building:
These are some of the more obvious indicators of unreinforced masonry. You can learn more about how to identify unreinforced masonry, and the problems unreinforced masonry can cause during an earthquake, here.