help me answer this about richter magnitude?

Question

http://www.sciencecourseware.org/VirtualEarthquake/php/DoRichter3.php?quakeregion=SA&dis0=345&theirsp0=35&dis1=384&theirsp1=39&dis2=594&theirsp2=61

Answer 1

Magnitude is
343
242
48

Richter magnitude is 6.7
you can still contact me if you want to learn how to read this

Answer 2

Amplitude and the distance found from seismograph is used to calculate the magnitude in Richter scale. The method differs for the intensity of quake to quake and place to place. The modern improved method is using moment magnitude method. Just for rough idea you can calculate like this for S wave. The amount of shaking will be 0.1 mm for Richter scale 3 when measured from the distance of 100 Kilometers. This shaking will increase by ten fold for each Richter scale. The distance will reduce the amplitude according the inverse square of the distance from epicenter. But more complicated calculations are adopted. Nothing gives exact result. We get only fairly reliable results. See the chart for energy release.
1. 30 lbs Approximate TNT for Seismic Energy Yield
2. 1 ton
3.29 ton
4.1000 ton
5.32000 ton
6.1 million ton
7.32 million ton
8.1 billion ton
9.32 billion ton