After more than 15 years covering everything Apple, it’s with a heavy heart we announce that we will no longer be publishing new content on iMore and the iMore forums will be closing as of November 1st, 2024.
How can I stop the loud alert sounds that occur unannounced
Try going into Settings>Notifications, then scrolling down until you reach two toggle switches: one for AMBER alerts, and the other for Emergency alerts. Make sure that both of these are off, if you don't want to receive (hear) the alert notifications for these.
Welcome to iMore! Are there any accompanying notifications? It's odd that you would hear an audible sound with nothing coming up on the screen. Perhaps it's a emergency or amber alert? These can be turned off in Settings > Notifications.
When you pull down Notification Center do you get any indication of what the alerts could be?