To change the time zone in GeoNet follow these steps:
1. Click on your Avatar and locate the Preferences option
2. On the Preferences page, in the General Preferences tab, scroll down to the timezone option and set you time zone.
3. Click Save once you have finished
If you would like to learn more about discussion view styles be sure to check out: What Are Flat and Threaded Views.
And if you would like to learn more about setting your email preferences read: Setup and Change GeoNet Email Preferences.