It's in the Seafloor Cavern, but it can also be found with the ability Pickup (no doubt somewhat rare though). The Pickup method is Emerald only for Gen 3 games.
u find it at the seafloor cavern
You don't talk to anyone to find TM 26 Earthquake you find the TM in the seafloor carvern.
Only by Tm
You find the TM Earthquake inside Victory Road.
NOWHERE.The TM trick is not available as a TM in Pokemon Emerald
you have to have a pokemon that hates you on the left
i dont now:Z
salamance didn`t learn earthquake but you can teach it using TM
you can buy it at lillicove departmeant store at TM floor
you can only find TM 25-thunder at lilicove department store.
U get it from the fossil maniac
the fossil maniacs brother