Inauguration+N or Inaugural+N ?

Hi. As I watched the inauguration ceremony yesterday, I am confused about making up the word related to inauguration.
here are example. I have seen these words on TV.
1.inauguration - inauguration address, inauguration buzz
2.inaugural - inaugural address, inaugural concert, inaugural safety

Some use inauguration+N. while some use inaugural+N. Are there any differences?
I also know that inaugural can be both noun and adjective. So from the example above, does inaugural really act as N. or adjective.?

Thanks.