I need help this is worth 15 points! sorry about the quality in advance!

So the star goes on Breckenridge, Colorado
1. The earthquake started in Colorado but it looks like it spread to Nevada and Arizona.
2. I would only say one because you can see that the color of the big ring is red and that shows the biggest point of where the earthquake is.

I might not be correct but those are just the answers that I would put. Hope this helped :)

Answer decreased soil salinity;