That earth looks a little dry.
Perhaps add water to lower its impedance.
I found a metal light fitting in my place with the ground wire wrapped arround a screw and screwed into the douglas fur framing.
The light circuits in NZ were often unearthed when my place was built in the 70s to save money on wire. This fitting was a later addition and I guess running a earth wire to meet modern rules was too hard for someone.