Answer: What you're seeing are ground nesting wasps. They can be aggressive if they feel threatened. The way that I deal with them is to wait until dusk when all the critters are in the nest and then turn a glass jar or glass bowl upside down over the hole. Glass allows you to see when the activity stops but you could use a metal can and just wait longer. The nest has only one entrance/exit hole. If you close the hole, the colony will die out - they won't dig another exit hole. Covering it with soil doesn't seem to work as well as covering it with a jar or bowl.
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