as is said+一个句子是个什么结构，分析主语，谓语，定语什么的。

Question

原句是as is said there has been a serious earthquake there.
翻译这句话，并指出结构和用法。
谢谢各位了。

Answer 1

据说那儿曾发生一次严重的地震。
as 主语 is said 谓语 there has been a serious earthquake there 真正主语

Answer 2

as is said 是固定形式 ，意为“据说”
there be "有…………"
has been 是根据想要表达的意思确定的，曾经发生过，所以用过去完成。
整句的意思是：据说那里曾经发生过大地震

Answer 3

这如传言那样，那里曾发生过一次大地震。
as is said 可以算作一种固定用法，意思是传说，据说等。