相あい次ついで

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い

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で

Meanings

Describes events or actions occurring repeatedly in a short period, often with a sense of urgency or rapid sequence.

〈事こと〉が相あい次ついで起おこるfor incidents to occur one after another
今年ことしに入はいって事じ故こが相あい次ついで起おこっている。
Accidents have been occurring one after another since the start of this year.
〈人ひと〉が相あい次ついで辞じ任にんするfor people to resign one after another
大だい臣じんが相あい次ついで辞じ任にんした。
The ministers resigned one after another.
〈物もの〉が相あい次ついで発はつ売ばいされるfor products to be released one after another
新あたらしいスマートフォンが相あい次ついで発はつ売ばいされている。
New smartphones are being released one after another.
〈事こと〉が相あい次ついで発はっ生せいするfor problems or incidents to occur in quick succession
台たい風ふうの影えい響きょうで被ひ害がいが相あい次ついで発はっ生せいしている。
Damage has been occurring one after another due to the typhoon.

次つぎ々つぎにN1
次々に is a neutral term for things happening one after another in any context, while 相次いで often implies a rapid or alarming series of events like accidents or resignations.
続つづけて
続けて simply means 'in a row' or 'continuously' without any implication of urgency, while 相次いで often carries a sense of alarming or notable repetition.
続ぞく々ぞくN2
相次いで is more formal and often used for a series of events happening closely together, whereas 続々 suggests an ongoing, continuous flow.
次つぎ々つぎN3
相次いで is a slightly formal word often used in news reports for successive events (e.g. accidents), while 次々 is more general and casual.

相あい変かわらずN3
相変わらず means 'as usual, still the same' and shares the あい- sound with 相次いで, but the two have completely unrelated meanings.

Compound of 相 (mutual, together) and the て-form of 次ぐ (to follow, to come next), literally 'mutually following'.