[Someone]

https://wildfiretoday.com/2022/01/17/hunga-tonga-volcano-tri...: “a ground-based lightning detection system recorded nearly 400,000 strikes with 200,000 occurring in a one-hour period.”

Lightning causes EMPs (https://en.wikipedia.org/wiki/Lightning#Transient_currents_d...) , so there were EMPs. I think/guess each one was a lot less powerful than that of a nuclear explosion, though.