As of this writing, Alexa routines (The ones you set up In the Alexa app) can only be triggered by a motion sensor, contact sensor, lock, flic button, or echo button. A vibration sensor won’t do it. So you have to look beyond the Alexa system itself to get this done.
This forum is for people who are using the Samsung SmartThings ™ home automation system, so all of the questions and answers are assumed to be in that context. It’s a very busy forum so it often comes up near the top of general home automation Google searches, but it’s not a general forum.
If you are interested in setting up a Samsung SmartThings system, then there are several vibration sensors that you can use to turn the light on, whether you have Alexa set up or not. And you can still use Alexa for voice control as desired.
But getting into the SmartThings options would require buying a hub and setting up a whole new system, which might be more than you’re interested in.
If you are interested in knowing more about that option, let us know, and we can talk about next steps.
Otherwise you might want to ask your question in the Amazon forums and see what suggestions people have for a simpler approach.