trip ****
actuate
trigger **
activate *
set off *
spark off
spark **
trigger off
touch off

The news touched off a drop of nearly 14 percent in the company's stock.

The only question is, why'd they touch that one off?

The action is certain to touch off a legal battle.

In fact, any such effort is likely to touch off a big political storm.

What the first attack hadn't done to touch off a national panic, the second did.

I would then have no further chance to influence the series of events that we touched off.

Even a season of bad crops could touch it off.

The very idea of journalism touched off something in him.

"If we started shooting at each other here, it could even touch off a war back home."

And actually going through one may touch off another fit.