Hi Rebecca, which earthquake do you refer to? The earthquake in 2008? The road from Chengdu to Jiuzhaigou and Huanglong has never been blocked. Feel free to visit it. There is nothing barrier at all.

I was there in end of May. The road to Huanglong is under construction and was not a very nice time in the coach. Also after the 2 hour ride we found that Huanglong di not have any water at all. That may have changed since then so best try to check with local before you put your self to the travel. If the water is there I think it would look fantastic. Enjoy your trip.