The trolls' worst enemy is a simple ditch around your base and spike traps. I've had a few hordes attack my base a long time ago (as in a good dozen at once) and I never had to do anything, they just slipped down the ditch and died from the spike extremely fast.
Just needed to repair the spikes from time to time.

"The Ground is Shaking" is an invasion event. Like all invasion events, drop everything and run outside of your base defences. I have killed more than 4 trolls during one of these events. I am pretty sure invasion event duration is based on time, it seems the quicker one kills the more there is to kill. When it ended I ran into the forest around my base and killed 3 more that were moving off.

I've experienced troll invasions, but they never get as far as actually reaching the base. Even an upgraded flint spear can tear through a staggered troll.

No I dont think troll caves are mobile, perhaps take your medication?

That's probably the 'The Ground Is Shaking'-event if there are two trolls. Other possibility is that you just have nasty neighbours.

a troll attack my base

i ddnt know it was possible

Originally posted by Mexican:

No I dont think troll caves are mobile, perhaps take your medication?

Lol.

Originally posted by ProFx:

i ddnt know it was possible

Welcome to Valheim :)

You just take it and rebuild after.
If you have tamed animals, well, you might not have them anymore after that event.

to prevent troll attacking my base i have to tame animals?

Originally posted by ProFx:

to prevent troll attacking my base i have to tame animals?

maybe have a look here , under Base-Protection/Raids

You didn't pay the troll toll.

You can prevent it by raising the ground like a wall around your base or alternatively dig a deep enough mote around it or even both. There are a numer of youtube videos on how to do it. It requires quite a bit of stone though to raise a wall so the mote idea is much easier to do.

Originally posted by ProFx:

a troll attack my base

Great materials delivered to your doorstep is always welcome
Just stay within the red circle and kite them away from your base. The event lasts couple of minutes so you can a) kill as many as you can within that time or b) kite them away from your base and kill only after the event is ended so that no more trolls spawn in.

There are many different events for your amusement
https://valheim.fandom.com/wiki/Events

Originally posted by sneakyweazel:

Originally posted by ProFx:

a troll attack my base

Great materials delivered to your doorstep is always welcome
Just stay within the red circle and kite them away from your base. The event lasts couple of minutes so you can a) kill as many as you can within that time or b) kite them away from your base and kill only after the event is ended so that no more trolls spawn in.

There are many different events for your amusement
https://valheim.fandom.com/wiki/Events

Troll event lasts 80 seconds. Its the shortest of all the events.

Originally posted by Qrazy:

You didn't pay the troll toll.

LOL