If you're worried about detecting earthquakes, I suggest a koi pond. Seriously.

Back in 1998, I was in Tokyo for a working group meeting.
One evening, three of us were admiring the garden and pond
behind the hotel (the Takanawa Prince, for the record). The
pond was fairly full of large koi - up to about 18 inches.

Suddenly - EVERY FISH IN THE POND LEAPED OUT OF THE WATER!
This was followed closely by three startled humans leaping
into the air! THAT was followed closely by the sudden sound
of everything - and I mean EVERYTHING - rattling, and the
ground swinging back and forth under our feet.

I estimate it lasted about 10 seconds, and something big
and metallic kept banging away for several seconds after
that. Given that nothing big seemed to be falling in or
down, we went back in the hotel. Several employees were
rushing about in an almost panic stricken state, worried
that customer service and elevators might be disrupted.
(They were no longer worried about the quake, just its
consequences...)

Anyway - I recommend the garden and koi pond. Relaxing
most of the time, and an earthquake warning when you
really need it.