“Email marketing” is a term that’s often used to describe marketing tactics that involve one-to-many messaging. In other words: “blasting” out emails to a list of subscribers.
“Marketing automation” is a term of confused with “inbound marketing”, which is a strategy far more focused on 1:1 conversations. Email is a perfectly good channel for making that happen, but there’s also text messages, or chats, amongst many others.
If you’d like a bit more clarity around the topic, I highly recommend this excellent guide written an international expert on the topic: Email Marketing vs Marketing Automation.
(Okay, really though: I wrote it. ;))