I was inspired by @samjshah to create an activity using logarithms and earthquakes for my algebra 2 classes. Sam wrote about Earthquakes, Richter Scale, and Logarithms here.
I did a little googling and ended up with this activity. I still had some questions, so I emailed USGS and got a quick and through reply. The reply resulted in this activity. I have not tried it with students yet, but I'm really excited to do so next year. Please feel free to check it out and give me feedback before I try it in the classroom.
Here is the student document if you'd like to use it.