Complex sentence: On 12 March 2011, in the immediate wake of the 2011 Tōhoku earthquake and tsunami, several reactors were badly struck by the tsunami and the Japanese government declared an "atomic power emergency" and evacuated thousands of residents living close to TEPCO's Fukushima I plant.
Split into simpler sentences: On 12 March 2011, in the immediate wake of the 2011 Tōhoku earthquake and tsunami, several reactors were badly struck. The Japanese government declared an "atomic power emergency" and evacuated thousands of residents living close to TEPCO's Fukushima I plant.