The phrase "affected prefecture" is correct and usable in written English.
It can be used in contexts discussing regions or administrative divisions that have been impacted by an event, such as a natural disaster or policy change.
Example: "The government has allocated funds to assist the residents of the affected prefecture following the recent earthquake."
Alternatives: "impacted region" or "stricken area".
Just 15% of the 29,000 permanent homes planned for survivors and nuclear evacuees have been completed in the three worst affected prefectures of Iwate, Miyagi and Fukushima.
A very similar or even more pronounced picture is shown in Fukushima's neighboring (or affected) prefectures.
Thus, although the prefectural and municipality government workers were working as public servants in the same disaster-affected prefecture and the former were investigated at a time closer to the disaster, severe psychological distress was more common in municipality workers.
South Korea has forbidden food imports from the Japanese prefectures affected by the nuclear crisis.
Similarly, Japan today is working towards building national memorials in the three prefectures affected by the earthquake, tsunami and radiation disasters of March , 2011
Thanks to these efforts, all prefectures affected by violence in the north of the country have access to UNICEF-sponsored water, sanitation and hygiene programmes.
The Japanese prefectures affected by the March 2011 Tohoku earthquake and tsunami are struggling to recover, but the infrastructure for disposing of an estimated 21.83 million tons of debris is not yet available.
Most stay in parts of Fukushima prefecture not affected by the evacuation order; the remainder are scattered among all but two of Japan's 46 other prefectures, according to village records.
Industrial structure and population differ among prefectures, affecting the efficiencies of individual prefectures.
It cannot do this by itself, and there is opposition in the rural prefecture chiefly affected.
