にわたってAcross or throughout a broad range
にわたって emphasizes that an event, state, or effect covers a broad period, area, number of occasions, or set of fields.
What it emphasizes
The noun before にわたって names the range being covered. Typical ranges include a long duration, a large geographic area, several occasions, or many fields. The construction draws attention to the breadth or scale of that coverage, so it is most natural when the range is substantial or noteworthy.
Broad periods and areas
Repeated occasions and broad fields
にわたって can cover repeated occasions rather than one continuous action. It can also show that a report, activity, or issue extends across several subject areas.
Breadth versus a stretch between points
にわたって foregrounds how broadly the whole range is covered. By contrast, から～にかけて identifies an approximate stretch between two named points.
イベントは九月から十一月にかけて各地で開催される。
The events will be held in various locations from around September through November.
AnalyzeThis sentence names an approximate time stretch; it does not primarily emphasize the scale of total coverage.
More examples
豪雨による停電は四つの市にわたって発生した。
Power outages caused by the torrential rain occurred across four cities.
Analyzeチームは六回にわたって安全試験を実施した。
The team conducted safety tests on six separate occasions.
Analyze資料には半世紀にわたる地域の変化が記録されている。
The materials record half a century of change in the region.
Analyzeその作家は小説、演劇、評論など多くの分野にわたって作品を残した。
The writer produced works in many fields, including fiction, drama, and criticism.
Analyze復旧作業は四か月間にわたって続いた。
The recovery work continued over a period of four months.
Analyze百キロにわたる海岸線でごみが確認された。
Debris was found along one hundred kilometers of coastline.
Analyze