The Notifications timeline in Twitter by default shows everyone who has interacted with your tweets.
This means any of your tweets that are liked, retweeted and username mentions by other users which are not even on the followers list are displayed. This can often generate a lot of notifications activity.
So this setting can be changed by which only activity of people from the followers list is displayed.
Here is how :
Access Settings from the Twitter profile drop-down menu.
Go to Notifications.
Enable the option Only people you follow. Finally, click on Save changes.