The magnitude between Haiti and Chile is far different. 7 and 8.5 respectively. You have to take into consideration however Haiti's construction standards is mediocre so that would have cost the lives of thousands of Haitians even if Haiti would not be densely populated. In this modern world, the building structures should meet the standards strong enough to withstand frequent earthquakes. Look at Bam, Iran when earthquake struck it in 2004. The houses toppled were mostly made of bricks or mud. Naturally, the structure is very weak in itself and it is understandable the death toll would rise as a result of that.