Possible Clues:

• Pianist identified with scale?
• Scale measuring magnitude of earthquakes
• Eponymous seismologist Charles
• Pianist better off keeping time
• Scale on which earth tremors are measured
• American seismologist
• Earthquakes are measured on this scale
• Scale for measuring earth tremors
• This scale measures the strength of earthquakes
• Wife dumped by author outside church — I understood the quaking!