题目选项分析

A nuclear test explosion detonated recently in the Pacific Ocean created a substantial blast with a yield of 7.3 kilotons; an earthquake with that force would measure as magnitude 5.1 on the Richter scale.

A nuclear test explosion detonated recently in the Pacific Ocean created a substantial blast with a yield of 7.3 kilotons, or magnitude 5.1 on the Richter scale as an earthquake.