Answer:
Magnitude of claimed earthquake = 10.363 (Approx)
Step-by-step explanation:
Magnitude of claimed earthquake = log√133,680 +  7.8
Magnitude of claimed earthquake = [1/2] log 133,680 + Â 7.8
Magnitude of claimed earthquake = 2.563 + Â 7.8
Magnitude of claimed earthquake = 10.363 (Approx)