Emergency alerts

If you mean the government emergency alerts, yes, they will sound even if the phone is on silent or do not disturb.

About emergency and government alerts on iPhone and Apple Watch - Apple Support

Dear Motdarnoc,

You can allow certain contacts to reach you in the event of an emergency, even when you have a Focus set up. Here's how: 

1. Open Contacts and select a contact.
2. Tap Edit, tap Ringtone or Text Tone, then turn on Emergency Bypass.
3. Tap Done.

Best regards,

Adam

Dear IdrisSeabright,

Your post is so helpful. This feature is not available in my region and I didn’t know about this.

Thank you! :)

Adam

I'm glad it help both you and the OP. I've learned so much hanging around these forums.

I would add that your answer is also quite good. I just guess better this time. ;-)