Sorry. Of course I misread your post. No earthquake -- that I know of -- at ZJJ. But then ZJJ didn't do much for me either, especially given the time it takes to get there. Huashan near Xi'an is a much nicer bet, and easy to reach. If you can get by in Chinese, Guoliang Cun and surrounds is spectacular, and not too far from Zhengzhou. Or maybe Wutaishan, with a stop at Pingyao.
Kaifeng has been redeveloped and lacks historical presence these days.
If you want awful modern urbanism, then skip Zhengzhou and head straight to Lanzhou. But make the trip worthwhile by dropping down to Xiahe, with a stopover in Linxia.
I've been to Kashgar a couple of times, but not for over a decade. Everything I've read suggests much of interest there has been destroyed and that the situation is tense. Indeed, Xinjiang as a whole is quite a tense place these days. You may have trouble finding a place to stay, at least if you're on a budget, and will always feel you are being watched. Don't take photos and be prepared to have your phone examined on departure. Security and cameras are everywhere. Not a fun place!