I’m not concerned merely about the earthquake, but about the tsunami. ne anlama geliyor?

Bir çeviriye bakın

Merely means 'only' or 'just'.

I'm not merely concerned about earthquake, but also the tsunami.
Same meaning:
I'm not only concerned about the earthquake, but also the tsunami.
I'm not just concerned about the earthquake, but also the tsunami.

Using 'the' here is a little unnatural without the context. if you are talking generally, I would say: ...about earthquakes, but also tsunamis.

But the 'the' here could mean 'the potential big one that we have been talking about':

A: We're due for a massive earthquake at some point. It's scary thinking about it, right?
B: Yeah, but living on the coast, I'm not merely concerned about the earthquake, but also the tsunami.