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.

When a nuclear test explosion was detonated recently in the Pacific Ocean, its substantial blast, which would be deemed magnitude 5.1 on the Richter scale for an earthquake, yielded 7.3 kilotons.