Explore Westonci.ca, the leading Q&A site where experts provide accurate and helpful answers to all your questions. Join our Q&A platform and get accurate answers to all your questions from professionals across multiple disciplines. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

All are necessary except the following for determining the Richter magnitude for earthquakes
a. distance to the epicenter
b. time difference between the arrival of the P and S waves
c. a seismogram the depth of the focus
d. the greatest amplitude on the seismogram