Does the trigger effect of Geartown activate if another field spell is activated in Yu-Gi-Oh?

No, Geartown's trigger effect does not activate if another field spell is activated.

Here's why:

* Geartown's effect: Geartown's effect triggers when a "Gear" monster is Special Summoned to your field.

* Other field spells: Activating a field spell does not involve Special Summoning a "Gear" monster.

Therefore, activating a field spell, even if it's a "Gear" themed field spell, will not trigger Geartown's effect.