segmentation fault (core dumped) example
Example 1: python segmentation fault (core dumped)
You might be working with a lot of data and your RAM is full
Example 2: segmentation fault (core dumped) ubuntu
See AU: What is a segmentation fault? post and also this post which have some examples how reproduce it, SO: What is segmentation fault?.
The simplest description I can come with (may be not the perfect):