Seismology at Caltech: Name the seismologist who created the magnitude scale commonly used to measure earthquake size. Identify the inventor of the Richter magnitude scale (1935). Choose the correct name.

Given data

• The question asks for the Caltech seismologist who invented the magnitude scale.

Concept / Approach
Charles F. Richter introduced the local magnitude scale in 1935; Beno Gutenberg collaborated and later extensions generalized magnitude concepts.

Why the others are incorrect
Mercalli created an intensity scale (damage-based), not a magnitude scale; Turner was an astronomer/seismologist but not the inventor of the magnitude scale.

Final Answer
Charles F. Richter.