2 things:
- your screenshot shows that your overall traffic is dropping but doesn't show how much of your actual search traffic is dropping.
- It's almost impossible for anyone here to pin point reason(s) for your search traffic drop from Google update unless they are well aware of both your site and Google update.
I read and replied cuz one of my sites dropped search traffic as well, then i fixed few things and it jumped back up but then again it's below average now.